Customer UMTS RF TAN U03.03 Power Control

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Use pursuant to Company instructions. Page 1 of 1

Subject: UMTS RF Translation Application Notes: Power Control U03.03 Version 8.01 Date: June 2006

Abstract This document provides with the description and implementation of power control algorithms for the UMTS Network Release U03.03 and covers the relevant translation parameters and their recommended values. Power Control is in charge of the regulation of the transmitted power level of the Node B and the User Equipment. It ensures that the quality of service required for every radio link is achieved irrespectively of the radio channel conditions and that the interferences are reduced. The new feature introduced in this document mainly consists in 384k uplink bearers. The Translation Application Notes specifically dedicated to HSDPA will contain information related to the Power Control for that feature.

Subject: UMTS RF Translation Application

Notes – Power Control – U03.03 Date: June 2006

Lucent Technologies - Proprietary Use pursuant to Company instructions.

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Version History Version Date Changes

1.0 11.15.2003 Draft version U01.03 Author: Sébastien Fritsch

1.1 02.01.2004 Correction of the parameter values based on the latest Release of U01.03.07.01 and opened MRs. Insertion of the comments provided by Stefan Brueck

2.0 02.20.2004 Correction of some Glossary terms. Insertion of the comments provided by Hussein Fawaz Final Release of the document.

3.0 02.25.2004 Draft version U01.04 Author: Sébastien Fritsch

4.0 06.15.2004 Final version U01.04: Set default Parameters values according to latest certified load

5.0 12.06.2004 Draft Version U02.01 Author: Sébastien Fritsch

7.0 06.01.2005 Draft Version U03.01 Author: Sébastien Fritsch

7.1 06.13.2005 Insertion of comments provided by reviewers. 8.0 05.15.2006 Version U03.03

Author: Sébastien Fritsch 8.01 05.17.2006 Change dLReferencePower from -20dB to -10dB (voice:

UEGTFCS=2)




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TABLE OF CONTENTS

1. GLOSSARY OF TERMS AND ABBREVIATIONS ..........................................................................6 2. REFERENCES...................................................................................................................................... 10 3. INTRODUCTION TO POWER CONTROL.................................................................................... 11

3.1. POWER CONTROL FOR DOWNLINK DEDICATED CHANNELS ......................................................... 11 3.1.1. Downlink Open Loop Power Control ...................................................................................... 11 3.1.2. Downlink Outer Loop Power Control ..................................................................................... 11 3.1.3. Downlink Inner Loop Power Control ...................................................................................... 12 3.1.4. Power Imbalance ..................................................................................................................... 12 3.1.5. DPCCH and associated DPDCHs........................................................................................... 13 3.1.6. Deactivation of the downlink inner loop power control ......................................................... 13 3.1.7. Downlink power control in compressed mode ........................................................................ 14

3.2. POWER SETTINGS FOR DOWNLINK COMMON CHANNELS ............................................................. 15 3.3. POWER CONTROL FOR UPLINK DEDICATED CHANNELS ............................................................... 17

3.3.1. Uplink Open Loop Power Control........................................................................................... 17 3.3.2. Uplink Outer Loop Power Control .......................................................................................... 17 3.3.3. Uplink Inner Loop Power Control........................................................................................... 17 3.3.4. Impact of Compressed Mode on uplink transmit power control............................................. 19

3.4. POWER CONTROL FOR UPLINK COMMON CHANNELS ................................................................... 20 3.5. POWER OVERLOAD CONTROL ....................................................................................................... 20

4. POWER CONTROL FOR DOWNLINK DEDICATED CHANNEL ........................................... 21 4.1. DOWNLINK DEDICATED CHANNEL FRAME STRUCTURE ............................................................... 21 4.2. INITIAL TRANSMIT POWER FOR DOWNLINK DEDICATED CHANNEL ............................................. 21

4.2.1. Downlink DCH Open Loop Power Control ............................................................................ 21 4.2.1.1. Downlink DCH Open Loop Power Control at Call set-up ............................................................21 4.2.1.2. Downlink DCH Open Loop Power Control in Cell_DCH state ....................................................22 4.2.1.3. Translation Settings ........................................................................................................................23

4.3. OUTER LOOP POWER CONTROL FOR DOWNLINK DEDICATED CHANNELS ................................... 23 4.3.1. Downlink DCH Outer Loop Power Control Principle............................................................ 23 4.3.2. Translation Settings ................................................................................................................. 24 4.3.3. Outer Loop Power Control and User Elements ...................................................................... 24

4.4. INNER LOOP POWER CONTROL FOR DOWNLINK DEDICATED CHANNEL ...................................... 25 4.4.1. Downlink DCH Inner Loop Power Control Principle ............................................................ 25 4.4.2. SIR Estimation and TPC Command Generation..................................................................... 26

4.4.2.1. TPC bit patterns ..............................................................................................................................26 4.4.2.2. TPC pattern during Radio Link synchronization ...........................................................................27 4.4.2.3. Downlink Inner Loop Timing.........................................................................................................28 4.4.2.4. Downlink Inner Loop Power Control Modes.................................................................................29 4.4.2.5. Translation Settings ........................................................................................................................29

4.4.3. Downlink Transmit Power Limits ............................................................................................ 29 4.4.3.1. Principle ..........................................................................................................................................29 4.4.3.2. Transition between xx_inactive and xx_active states ....................................................................30 4.4.3.3. Downlink Inner Loop Power Control Algorithm and Execution ..................................................31 4.4.3.4. Downlink Inner Loop Transmit Power Step Size ..........................................................................32




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4.4.3.5. Translation Settings ........................................................................................................................33 4.4.4. Downlink Dynamic Range ....................................................................................................... 33

4.4.4.1. Downlink Transmit power limits from the NodeB ........................................................................33 4.4.4.2. Downlink Transmit power limits from the RNC ...........................................................................34 4.4.4.3. Downlink Transmit Power Limits in Softer Handover..................................................................34 4.4.4.4. Tuning of Pmax and Pmin ..............................................................................................................34 4.4.4.5. Translation settings .........................................................................................................................35

4.4.5. Downlink power control in compressed mode ........................................................................ 36 4.4.5.1. Impact of compressed mode on the Power Control function.........................................................36 4.4.5.2. DL power step size in compressed mode .......................................................................................37 4.4.5.3. Calculation of PSIR(k)......................................................................................................................37 4.4.5.4. DL transmit power range aspects ...................................................................................................38 4.4.5.5. Impact of DL compressed mode on the behavior of the UE..........................................................38 4.4.5.6. Translation Settings ........................................................................................................................39

4.4.6. Power Imbalance ..................................................................................................................... 39 4.4.6.1. Introduction.....................................................................................................................................39 4.4.6.2. Power Balance Procedure at the RNC............................................................................................41 4.4.6.3. Imbalance correction at the Drift RNC ..........................................................................................42 4.4.6.4. Estimation of Pbal ............................................................................................................................43 4.4.6.5. Limitation at the NodeB .................................................................................................................44 4.4.6.6. Translation Settings ........................................................................................................................46

4.4.7. Power Offset between Downlink DPCCH and its DPDCHs .................................................. 46 4.4.7.1. Principle ..........................................................................................................................................46 4.4.7.2. Impact of PO1 and PO3 on the radio link ......................................................................................47 4.4.7.3. Dynamic management of the downlink power offset PO2............................................................47 4.4.7.4. Translation settings .........................................................................................................................48

4.4.8. Deactivation of the downlink ILPC ......................................................................................... 49 5. POWER SETTINGS FOR DOWNLINK COMMON CHANNELS.............................................. 51

5.1. INTRODUCTION .............................................................................................................................. 51 5.2. POWER CONTROL PROCEDURES .................................................................................................... 51 5.3. COMMON PILOT CHANNEL AND SYNCHRONIZATION CHANNEL POWER....................................... 52 5.4. PRIMARY COMMON CONTROL PHYSICAL CHANNEL POWER ........................................................ 53 5.5. SECONDARY COMMON CONTROL PHYSICAL CHANNEL POWER ................................................... 53 5.6. PAGING INDICATOR AND ACQUISITION INDICATOR CHANNELS POWER....................................... 55 5.7. DOWNLINK LOAD DUE TO COMMON CHANNELS POWER SETTINGS ............................................. 56 5.8. TRANSLATION SETTINGS ............................................................................................................... 57

6. POWER CONTROL FOR UPLINK DEDICATED CHANNELS................................................. 58 6.1. UPLINK DEDICATED CHANNELS FRAME STRUCTURE ................................................................... 58 6.2. INITIAL TRANSMIT POWER FOR UPLINK DEDICATED CHANNELS ................................................. 58

6.2.1. Uplink DCH Open Loop Power Control ................................................................................. 58 6.2.2. Uplink DPCCH Power Control Preamble .............................................................................. 59 6.2.3. Translation Settings ................................................................................................................. 60

6.3. OUTER LOOP POWER CONTROL FOR UPLINK DEDICATED CHANNELS........................................... 61 6.3.1. Uplink DCH Outer Loop Power Control Principle ................................................................ 61 6.3.2. Inter-RNC soft handover.......................................................................................................... 62




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6.3.3. Radio Link Quality Estimation ................................................................................................ 63 6.3.3.1. BLER metric ...................................................................................................................................63 6.3.3.2. Quality Estimation metrics .............................................................................................................63

6.3.4. Frame Selector Function ......................................................................................................... 66 6.3.5. Uplink Outer Loop Power Control Algorithm......................................................................... 66

6.3.5.1. Principle ..........................................................................................................................................66 6.3.5.2. Translation settings .........................................................................................................................69

6.3.6. Outer Loop Power Control Execution..................................................................................... 70 6.4. INNER LOOP POWER CONTROL FOR UPLINK DEDICATED CHANNELS.............................................. 72

6.4.1. Uplink Inner Loop Power Control Principle........................................................................... 72 6.4.2. SIR Estimation and TPC Commands Generation ................................................................... 72

6.4.2.1. SIR Estimation................................................................................................................................72 6.4.2.2. Transmit Power Control commands...............................................................................................73

6.4.3. Uplink Inner Loop Power Control Algorithms........................................................................ 74 6.4.3.1. Overview.........................................................................................................................................74 6.4.3.2. Algorithm 1 for processing TPC commands..................................................................................75 6.4.3.3. Algorithm 2 for processing TPC commands..................................................................................76 6.4.3.4. Translation settings .........................................................................................................................78

6.4.4. Uplink Inner Loop Power Control Execution ......................................................................... 78 6.4.4.1. Principle ..........................................................................................................................................78 6.4.4.2. Transmit Power Step Size...............................................................................................................79 6.4.4.3. Transmit power limits – Maximum transmit power ......................................................................79 6.4.4.4. Transmit power limits – Minimum transmit power .......................................................................79 6.4.4.5. Translation Settings ........................................................................................................................79

6.4.5. Uplink DPCCH/DPDCH power gains .................................................................................... 80 6.4.5.1. Effect of bit rate variability on uplink power control ....................................................................80 6.4.5.2. Gain factors controlling procedures ...............................................................................................82 6.4.5.3. Translations settings .......................................................................................................................84

6.4.6. Impact of Compressed Mode on uplink transmit power control............................................. 86 6.4.6.1. Impact at the UE .............................................................................................................................86 6.4.6.2. Impact on the uplink SIR target......................................................................................................89

6.4.7. Translation Settings ................................................................................................................. 90 7. POWER CONTROL FOR UPLINK COMMON CHANNELS..................................................... 90 8. POWER OVERLOAD CONTROL ................................................................................................... 91

8.1. UPLINK OVERLOAD CONTROL........................................................................................................ 91




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1. Glossary of Terms and Abbreviations 3GPP 3rd Generation Partnership Project AI Acquisition Indicator AICH Acquisition Indicator Channel AOC Aggregate Overload Control BCCH Broadcast Control Channel BCH Broadcast Channel BER Bit Error Rate BLER Block Error Rate CFN Connection Frame Number CM Compressed Mode CN Core Network CPICH Common Pilot Channel CRC Cyclic Redundancy Checksum CRCI CRC Indicator C-RNC Control-RNC CS Circuit Switched DCH Dedicated Channel DL Downlink DPCCH Dedicated Physical Control Channel DPCH Dedicated Physical Channel DPDCH Dedicated Physical Data Channel D-RNC Drift-RNC DSP Digital Signal Processor DTX Discontinuous Transmission FACH Forward Access Channel FP Framing Protocol HSDPA High Speed Downlink Packet Access IAOC Improved Aggregate Overload Control ID Identity IE Information Element ILPC Inner Loop Power Control ITP Initial Transmit Power LMT Local Maintenance Tool / Terminal MAC Medium Access Control MAOC Modified Aggregate Overload Control MIB Master Information Block NBAP NodeB Application Part NDP Network Data Provision OAM Operation And Maintenance OLPC Outer Loop Power Control OMC Operations and Maintenance Centre OMC-U OMC for UMTS P-CCPCH Primary Common Control Physical Channel PCH Paging Channel PCA Power Control Algorithm PCP Power Control Preamble P-CPICH Primary CPICH




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PHY Physical layer PICH Page Indicator Channel PS Packet Switched P-SCH Primary SCH QE Quality Estimation QoS Quality of Service QPSK Quadrature (Quaternary) Phase Shift Keying RAB Radio Access Bearer RACH Random Access Channel RF Radio Frequency RLC Radio Link Control RLS Radio Link Set RNC Radio Network Controller RNSAP Radio Network Subsystem Application Part RPL Recovery Period Length RPP Recovery Period Power Control Mode RRC Radio Resource Control RSCP Received Signal Code Power SAE System Architecture and Performance Engineering S-CCPCH Secondary Common Control Physical Channel S-CPICH Secondary CPICH SER Symbol Error Rate SIB System Information Block SIR Signal-to-Interference Ratio S-RNC Serving RNC S-SCH Secondary Synchronization Channel TFC Transport Format Combination TFCI Transport Format Combination Indicator TFCS Transport Format Combination Structure TPC Transmit Power Control UE User Equipment UEGTFC User Equipment Group Transport Format Combination UEGTFCS User Equipment Group Transport Format Combination Set UL Uplink UMTS Universal Mobile Telecommunications System UTRAN UMTS Terrestrial Radio Access Network Note on the UMTS ParCat Attributes: RNC-CLI the parameter is a local RNC parameter accessible via CLI script RW-EL read-write parameter only when the top-level object locked RW-LO read-write parameter only when locked RW-PL read-write parameter only when parent object locked OMC the parameter is accessible via OMC-U RW-LO read-write parameter only when locked RW-PL read-write parameter only when parent object locked Note on the Parent Objects with Multiple Instances:




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The parameters related to power control parameters can be defined differently either on a radio bearer or service combination basis. The instances related to defined radio bearer (via object DedicatedTransportChannel) and service combination (via object UEGTFCS) are reported in Table 2 and Table 1.

Logical Object UEGTFCS Instances

Service Combination Uplink

Service Combination Downlink

1 3.4kbps signalling alone 3.4kbps signalling alone 2 3.4kbps signalling + speech 12kbps 3.4kbps signalling + speech 12kbps 3 3.4kbps signalling + CS 64kbps 3.4kbps signalling + CS 64kbps 4 3.4kbps signalling + PS 64kbps 3.4kbps signalling + PS 64kbps 5 3.4kbps signalling + PS 64kbps 3.4kbps signalling + PS 384kbps 6 3.4kbps signalling + PS 64kbps

+ speech 12kbps 3.4kbps signalling + PS 64kbps + speech 12kbps

7 3.4kbps signalling + PS 64kbps + speech 12kbps

3.4kbps signalling + PS 384kbps + speech 12kbps

9 3.4kbps signalling + PS 64kbps 3.4kbps signalling + PS 128kbps 11 3.4kbps signalling + PS 64kbps


13 3.4kbps signalling + PS 8kbps 3.4kbps signalling + PS 8kbps 14 3.4kbps signalling + PS 8kbps


19 3.4kbps signalling + PS 64kbps 3.4kbps signalling + HSDPA 23 3.4kbps signalling + PS 64kbps

+ speech 12kbps 3.4kbps signalling + HSDPA + speech 12kbps

26 3.4kbps signalling + PS 128kbps 3.4kbps signalling + HSDPA


3.4kbps signalling + HSDPA + speech 12kbps

31 3.4kbps signalling + PS 128kbps 3.4kbps signalling + PS 64kbps 32 3.4kbps signalling + PS 128kbps 3.4kbps signalling + PS 128kbps 33 3.4kbps signalling + PS 128kbps 3.4kbps signalling + PS 384kbps










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Logical Object

UEGTFCS Instances Service Combination

Uplink Service Combination

Downlink 47 3.4kbps signalling + PS 384kbps 3.4kbps signalling + PS 64kbps 48 3.4kbps signalling + PS 384kbps 3.4kbps signalling + PS 128kbps 49 3.4kbps signalling + PS 384kbps 3.4kbps signalling + PS 384kbps 50 3.4kbps signalling + PS 384kbps 3.4kbps signalling + HSDPA








3.4kbps signalling + HSDPA + speech 12kbps

Table 1: UEGTFCS Instances and associated service combination.

Object number Defines

1 Standalone Signalling 3.4kbps 2 Speech 12kbps RAB sub flow #1 3 Speech 12kbps RAB sub flow #2 4 Speech 12kbps RAB sub flow #3 5 64kbps CS 6 64kbps PS 7 384kbps PS 9 128kbps PS

19 DL HSDPA UL 128k PS Int/BG 20 DL 64k UL 128k PS Int/BG 21 DL 128k UL 128k PS Int/BG 22 DL 384k UL 128k PS Int/BG 27 DL 64k UL 384k PS Int/BG 28 DL 128k UL 384k PS Int/BG 29 DL 384k UL 384k PS Int/BG 30 DL HSDPA UL 384k PS Int/BG

Table 2:DedicatedTransportChannel instances and associated radio bearer.




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2. References [1] 3GPP TS25.211 “Physical channels and mapping of transport channels onto physical channels

(FDD)” [2] 3GPP TS25.214 “Physical Layer Procedures (FDD)” [3] 3GPP TS25.215 “Physical Layer; Measurements (FDD)” [4] 3GPP TS25.101 "User Equipment (UE) Radio transmission and reception (FDD)" [5] 3GPP TS25.104 "Base Station (BS) Radio transmission and reception (FDD)" [6] 3GPP TS25.133 "Requirements for Support of Radio Resource Management (FDD)" [7] 3GPP TS25.331 “Radio Resource Control (RRC) protocol specification” [8] 3GPP TS25.423 “UTRAN Iur interface Radio Network Subsystem Application Part (RNSAP)

signalling” [9] 3GPP TS25.427 “UTRAN Iub/Iur interface user plane protocols for DCH data streams” [10] 3GPP TS25.433 “UTRAN Iub interface NBAP Specification” [11] 3GPP TS25.321 “Medium Access Control (MAC) protocol Specification” [12] 3GPP TS34.108 “Common Test Environments for User Equipment (UE) Conformance Testing” [13] UMTS RF Translation Application Notes: Load Control Algorithms [14] UMTS RF Translation Application Notes: Handover [15] UMTS RF Translation Application Notes: Access Procedures [16] UMTS RF Translation Application Notes: HSDPA




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3. Introduction to Power Control Power Control is implemented in the Downlink Dedicated Channels, Downlink Common Channels, Uplink Dedicated Channels and Uplink Common Channels. At radio link establishment, the transmit power level is estimated without any information from the counter part. This procedure is known as open loop power control. Once a link is established, the power is continuously optimized using a loop including UE, NodeB and RNC. This procedure is known as closed loop and is split into two sub-control loops, the inner loop and the outer loop.

3.1. POWER CONTROL FOR DOWNLINK DEDICATED CHANNELS

3.1.1. Downlink Open Loop Power Control

At radio link establishment, the initial downlink transmit power of the DCH is determined by the open loop power control, depending on whether the UE has already another existing radio link or not. The parameters related to the downlink open loop power control are listed in Table 3.

Top Object: Parent Object

Parameter name Short Description Default

EcNotarget (prev. slRTarget)

Used for the calculation of the initial transmit power of the first radio link.

dLPowerMargin This margin is used in order to allow changes in the linkbudget between the time the CPICH measurements are performed at the UE and the time the first radio link is active.

UEGTFCS: DLDPCHInfo

newLegPowerOffset Used for the calculation of the initial transmit power of the radio links other than the first one.

See 4.2.1.3

Table 3: Power control at radio link establishment – downlink related parameters

3.1.2. Downlink Outer Loop Power Control

The downlink outer loop power control sets the target Signal to Interference Ratio that needs to be achieved at the UE to ensure the performances, in terms of Block Error Rate, requested for the downlink DCH. The parameter is described in Table 4 and can be set on a per radio bearer basis.

Parent Object Parameter name Short Description Default DedicatedTransportChannel bLERQualityTarget It provides the Downlink BLERtarget. See 4.3.2

Table 4: Downlink outer loop power control - Performance target parameter




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3.1.3. Downlink Inner Loop Power Control

The inner loop power control generates the transmit power control commands based on the SIRtarget provided by the outer loop power control. This ensures a fast adaptation of the NodeB transmit power for the considered downlink DCH. Different downlink power control modes can be supported by the UE to reduce the rate at which the NodeB adjust the power based on the TPC commands. In order to restrict the downlink interference, a maximum and minimum transmit power level with respect to the P-CPICH are defined per radio link for the downlink DCH irrespectively of the TPC commands. The minimum downlink power level can also be used e.g. to artificially maintain the call at a higher-than-needed level in order to improve the performances of the system (reduce call drop rates etc…). The parameters controlling the downlink inner loop power control are listed in Table 5.


Parameter name

Short Description Default

DedicatedTransportChannel

limitedDLPowerIncrease

Indicates whether DL power increase limitation is allowed for the DPDCH where it is mapped

PowerRaiseLimit Parameter for the DL Power Increase Limitation algorithm.

LCell DLPowerAvWindowSize

Parameter for the DL Power Increase Limitation algorithm.

tPCStepSize It defines the adjustment step specified in the downlink power control commands.

See 4.4.3.5

dPCMode It defines the Downlink Power Control modes supported by the UE.

See 4.4.2.5

minDLPower Minimum downlink power level for a given code power.

UEGTFCS: DLDPCHInfo

maxDLPower Maximum downlink power level for a given code power.

PminCorrectionFactor

Local correction to the value of minDLPower used to define the DL dynamic range of dedicated radio links on a cell basis.

LCell PmaxCorrectionFactor

Local correction to the value of maxDLPower used to define the DL dynamic range of dedicated radio links on a cell basis.

See 4.4.4.5

Table 5: Downlink inner loop power control - DPC mode parameter.

3.1.4. Power Imbalance

In some conditions the error rate of the power control command detection becomes high on the weakest link of a connection. When such an error occurs, the power control




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command may be interpreted as a “Power_Up” (wrong value) whilst on the other leg(s) it is interpreted as a “Power_Down” (correct value); this results in downlink DCH power levels diverging by twice the power adjustement step size (e.g. 2dB). This effect is known as power imbalance. The parameters involved in the procedure to correct it are listed in Table 6.

Top Object:

Parent Object Parameter name Short Description Default

ImbalanceCorrection Defines if imbalance correction of downlink transmit power should be activated or not.

maxAdjustmentStep Defines a time period, in terms of number of slots, in which the accumulated power adjustment shall be maximum 1dB. This value does not include the DL inner loop PC adjustment.

adjustmentPeriod Maximum time allowed for the application of the balance correction which value has been calculated at the beginning of the correction period.

scaleAdjustmentRatio Defines the convergence rate used for the associated Adjustment Period.

UEGTFCS: DLDPCHInfo

dLReferencePower Reference Power level for imbalance correction algorithm

See 4.4.6.6

Table 6: Power Imbalance

3.1.5. DPCCH and associated DPDCHs

The downlink transmit power control procedure controls simultaneously the power of a Dedicated Physical Common Control Channel and the corresponding Dedicated Physical Data Control Channels. The power of the DPCCH is adjusted with respect to the power of DPDCHs using the parameters listed in Table 7.

3.1.6. Deactivation of the downlink inner loop power control

The downlink Inner Loop Power Control can be deactivated at the NodeB for a group of radio links belonging to the same Node B communication context. This feature is not expected to be used in the Lucent Technologies RRM strategy. However the message could be generated by a non-Lucent Technologies Drift-RNC or could be of some use for test purposes. This is done using the parameter innerLoopPCStatus described in Table 8.




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Top Object:

Parent Object Parameter name Short Description Default

pO1 Power offset for the TFCI bits. Values greater than zero for TFCI power offset may improve the BLER performances.

pO2ForOneRLSet Power offset for the TPC bits when there is only one radio link set connected to the UE. Values greater than zero for this offset may reduce the TPC command error detection rate.

pO2ForTwoRLSet Power offset for the TPC bits when there are two radio links set connected to the UE. Values greater than zero for this offset may reduce the TPC command error detection rate.

pO2ForThreeRLSet AndMore

Power offset for the TPC bits when there are three radio links set connected to the UE. Values greater than zero for this offset may reduce the TPC command error detection rate.

UEGTFCS: DLDPCHInfo

pO3 Power offset for the pilot bits. Current default value for pilot power offset improves the UE synchronization and increases the downlink capacity gain.

See 4.4.7.4

Table 7: Downlink inner loop power control - Power offsets parameters



UEGTFCS: DLDPCHInfo

innerLoopPCStatus Activate / deactivated the inner loop power control feature.

See 4.4.8

Table 8: Activation / Deactivation of the Inner Loop Power Control

3.1.7. Downlink power control in compressed mode

The downlink power control procedure in compressed mode has for purpose to recover as fast as possible a signal-to-interference ratio close to the EcNotarget after each transmission gap. The UE is behaving on a similar way as it does in non-compressed mode, generating the TPC commands based on a comparison of the DL EcNoestimate and the DL EcNotarget.

However during the radio frames when compressed mode idle period takes place an alternative EcNo target value is used. This is calculated using a new variable DELTA SIR, which is calculated based on the new parameters delta SIR1, delta SIR1After, delta SIR2 and deltaSIR2After introduced in Table 9.




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Parent Object Parameter

name Short Description Default

Value deltaSIR1 Delta SIR target value to be set in the NodeB

during the frame containing the start of the first transmission gap in the transmission gap pattern (without including the effect of the bit-rate increase). This Delta will be applied to the uplink/downlink transmission power control procedure.

deltaSIRAfter1 Delta SIR target value to be set in the Node-B one frame after the frame containing the start of the first transmission gap in the transmission gap pattern.

deltaSIR2 Delta SIR target value to be set in the Node-B during the frame containing the start of the second transmission gap in the transmission gap pattern (without including the effect of the bit-rate increase). When omitted, DeltaSIR2 = DeltaSIR1.

LRNC: Transmission GapPattern

deltaSIRAfter2 Delta SIR target value to be set in the Node-B one frame after the frame containing the start of the second transmission gap in the transmission gap pattern. When omitted, DeltaSIRAfter2 = DeltaSIRAfter1

See 4.4.5.6

Table 9 – Compressed Mode Parameters

3.2. POWER SETTINGS FOR DOWNLINK COMMON CHANNELS

The following common channels for physical downlink are supported in U03.03: • Common Pilot Channel with sub-channels Primary CPICH (P-CPICH) • Primary Common Control Physical Channel (P-CCPCH) that carries the BCH • Secondary Common Control Physical Channel (S-CCPCH) that carries the FACH

and PCH. • Synchronization Channel (SCH) with sub-channels Primary SCH and Secondary

SCH. • Paging Indicator Channel PICH • Acquisition Indicator Channel AICH

The power level of all the downlink common channels is controlled using the parameters listed in Table 10.




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pCPICHpower Primary CPICH power, in dBm The setting strongly depends on the cell planning. This setting influence the power of the other DL common channels, the DL DCH power limits values and the IAOC scaling factors. CPICH power has also strong impact on synchronization as well as on soft/softer handover procedures.

pSCHpower Primary SCH power, in dB with respect to P- CPICH power Current setting ensures high success rate in different steps of cell search/synchronization procedure as well as low DL power consumption (duty cycle 10%).

sSCHpower Secondary SCH power, in dB with respect to P-CPICH power. Current setting ensures high success rate in different steps of cell search/synchronization procedure as well as low DL power consumption (duty cycle 10%).

LCell

bCHPower BCH power , in dB with respect to P-CPICH power Current setting ensures high success rate in decoding SIB and MIB messages as well as low DL power consumption (duty cycle 90%).

See 5.8

secondaryCCPCH.powerOffset1

Power offset of the Secondary CCPCH TFCI field relative to the transmission power of the data part (PCH or FACH). Values greater than zero for TFCI power offset may improve the BLER performances


Power offset of the Secondary CCPCH pilot field relative to the transmission power of the data part (PCH or FACH). Values greater than zero for pilot power offset may help the UE to achieve synchronization and perform a better reception of the S-CCPCH.

pCHPower PCH power, in dB with respect to P-CPICH power

LCell: SCCPCHPch

pICHPower PICH power, in dB with respect to P-CPICH power fACHTrafPower FACH power, in dB with respect to P-CPICH power. fACHSigPower FACH power, in dB with respect to P-CPICH power secondaryCCPCH.powerOffset1

Same as for the SCCPCHPch

LCell: SCCPCHFach


Same as for the SCCPCHPch

LCell: PRACH

aICHPower Defines the output power level of the AICH physical channel, in dB with respect to P-CPICH power. Current setting ensure successful decoding at the UE of AI messages along RACH Access procedures.

See 5.8

Table 10: Downlink common channels power parameters




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3.3. POWER CONTROL FOR UPLINK DEDICATED CHANNELS

As described for the downlink channels, an open loop and a closed loop power control are used for the uplink dedicated channels.

3.3.1. Uplink Open Loop Power Control

During the radio link establishment the open loop control procedure sets an initial transmitted power in the UE for the uplink dedicated channel. Additionally a power control preamble following the transmission of uplink DPCCH can be used to make sure that the ILPC has converged before the start of the uplink DPDCH transmission. The related parameters are included in Table 11.

3.3.2. Uplink Outer Loop Power Control

In the NodeB(s), the uplink outer loop sets and adjusts the SIRtarget in order to achieve the performance targeted for the uplink DCH. This target is expressed in terms of Block Error Rate. The method used to calculate the optimal SIR target value for providing the requested BLER is Lucent Technologies proprietary and the parameters related to this algorithm are listed in Table 12. Except for the first parameter all the other parameters are set on a per radio bearer basis.



dPCCHPowerOffset Used to determine initial transmit power of a new DTCH. Value expressed in dB.

UEGTFCS: ULDPCHInfo

pCPreamble Indicates length of power control preamble. Expressed in number of radio frames. No PC preamble is currently used to delay uplink DPDCH transmission after uplink DPCCH transmission. The reason is that some UEs crash if the value is other than 0.

See 6.2.3

Table 11: Power control at radio link establishment – uplink related parameters.

3.3.3. Uplink Inner Loop Power Control

The uplink inner loop power control adjusts the transmit power of the UE in order to achieve the SIRtarget provided by the uplink outer loop for a considered uplink DCH. The NodeB generates transmit power control commands that are sent to the UE. Irrespectively of the commands, the transmit power of the UE must remain within a power range defined by a minimum power and the maximum power. The minimum power depends only on the UE capability while the maximum power is specified by the RNC per radio bearer combination. There are two algorithms supported by the UE to combine different TPC commands when in soft/softer handover into a single one. The related parameters are listed in Table 13.




Page 18 of 18



qESelector It defines the metric to be selected for radio link quality estimation. This settings means that the selected metric for radio link quality estimation is the Physical Channel BER.

See 6.3.3.2.3

downSIRStep It defines the uplink SIRtarget decrement step in dB. Current values ensure quick OLPC reaction in highly variable RF environment without causing spikes in SIRtarget.

upSIRStep It defines the uplink SIR target increment step in dB. Current values ensure quick OLPC reaction in highly variable RF environment without causing spikes in SIRtarget.

qEThreshold It defines the QE threshold for allowing decrement of SIRtarget in dB. This value disables the check in OLPC on the Quality Estimation, thus OLPC decision on SIRtarget calculation are based only on CRC check results.

sIRAllowance It defines the hysteresis factor used to restrict SIR target update in dB.

sIRDownAdditional Extra UPLINKSIR target decrement when a Transport block is received with CRCI = ok. Used when High Speed SIR Target Decrease is active.

DedicatedTransportChannel

NbOfConsecutiveGoodFramesThreshold

Threshold for activation of High Speed SIR Target Decrease

See 6.3.6

initialSIRTarget Initial SIRtarget for the considered radio bearer expressed in dB. Setting depends on power imbalance and DL OLPC issues. Should be further optimized in order to minimize the convergence time, hence the uplink power consumption & noise rise during the transient period.

minSIRTarget Minimum SIR target for considered radio bearer in dB.

UEGTFCS: ULDPCHInfo

maxSIRTarget Maximum SIR target for considered radio bearer in dB.

See 6.3.5.2

Table 12: Uplink outer loop power control parameters.




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tPCStepSizeUL Adjustment step specified in the uplink power control commands 0 means 1dB, 1 means 2dB steps.

maxULDPCHPower This is the highest permitted value ensuring maximum uplink coverage. It may be decreased in case of uplink interference issues.

See 6.4.4.5 UEGTFCS:

ULDPCHInfo

PowerControlAlgorithm It specifies the algorithm to be used by UE to interpret TPC commands

See 6.4.3.4

Table 13: Uplink inner loop power control - TPC related parameters.



gainFactorBc It defines the DPCCH gain given for the highest rate of the Transport Format Combination Structure (TFCS). Current values help to mitigate the power imbalance effects by increasing both DPCCH and DPDCH performances without causing high uplink power consumption.

gainFactorBd It defines the DPDCH gain given for the highest rate of the TFCS. Current values help to mitigate the power imbalance effects by increasing both DPCCH and DPDCH performances without causing high uplink power consumption

gainFactorType It defines the method to either directly signalling or computing the gain factors.

UEGTFC

referenceTFC It defines the reference number in case computed method is used.

See 6.4.5.3

Table 14: Uplink inner loop power control - DPCCH/DPDCH power gains parameters.

In order to make the quality of service provided to a DPCH independent from the instant data rate, power gains between the uplink DPDCH and DPCCH have been introduced for every uplink service combination. The parameters are listed in Table 14.

3.3.4. Impact of Compressed Mode on uplink transmit power control

As in the Downlink the principle of the Power Control in the uplink when in compressed mode is not fundamentally different from the normal case. The power will be adapted before and after the transmission gaps in order to ensure the continuity of the service and the recovery. The SIR Target will, as for the Downlink, be adapted during the transmission gaps using new parameters as defined in Table 15




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Parent Object Parameter name

Short Description Default Value

deltaSIR1 Delta SIR target value to be set in the UE during the frame containing the start of the first transmission gap in the transmission gap pattern (without including the effect of the bit-rate increase). This Delta will be applied to the uplink/downlink transmission power control procedure.

deltaSIRAfter1 Delta SIR target value to be set in the UE one frame after the frame containing the start of the first transmission gap in the transmission gap pattern.

deltaSIR2 Delta SIR target value to be set in the UE during the frame containing the start of the second transmission gap in the transmission gap pattern (without including the effect of the bit-rate increase). When omitted, DeltaSIR2 = DeltaSIR1.

LRNC: Transmission GapPattern

deltaSIRAfter2 Delta SIR target value to be set in the UE one frame after the frame containing the start of the second transmission gap in the transmission gap pattern. When omitted, DeltaSIRAfter2 = DeltaSIRAfter1

See 4.4.5.6


3.4. POWER CONTROL FOR UPLINK COMMON CHANNELS

The power control procedure for the uplink common channels applies only to the RACH channel since this is the only uplink common channel supported in U03.03. All the RACH procedures including the power control mechanism are covered in [15].

3.5. POWER OVERLOAD CONTROL

A power overload control function has been introduced in order to keep the total downlink transmitted power level in the short term within an acceptable range. This function is located in the NodeB and is implemented by the use of the Improved Aggregate Overload Control procedures. These functions are controlled by NodeB internal parameters and by the UTRAN parameter listed in Table 16.



LCell maxTransmissionPower Maximum downlink power, in dBm allowed in the cell. 43.0dBm

Table 16: Power overload control parameter.




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4. Power Control for Downlink Dedicated Channel

4.1. DOWNLINK DEDICATED CHANNEL FRAME STRUCTURE

As specified in [1] the Dedicated Physical Channel is the only type of downlink dedicated physical channel. Within one downlink DPCH, dedicated data generated at RLC/MAC Layer and upper layers, i.e. the Dedicated Transport Channel, is transmitted in time-multiplex with control information generated at Physical Layer. This control information includes known pilot bits, the Transmit Power Control commands and an optional Transport Format Combination Indicator. Figure 1 shows the frame structure of the downlink DPCH.

One radio frame, Tf = 10 ms

TPC NTPC bits

Slot #0 Slot #1 Slot #i Slot #14

Tslot = 2560 chips, 10*2k bits (k=0..7)

Data2 Ndata2 bits

DPDCH TFCI

NTFCI bitsPilot

Npilot bits Data1

Ndata1 bits

DPDCH DPCCH DPCCH

Figure 1: Downlink DPCH frame structure. Each frame of length 10 ms is split into 15 slots, each of length Tslot = 2560 chips, corresponding to one power-control period. Therefore the maximum rate of power control commands is equal to 1500 Hz. The parameter k in Figure 1 determines the total number of bits per downlink DPCH slot. More information concerning DPCH frame structure can be found in [1].

4.2. INITIAL TRANSMIT POWER FOR DOWNLINK DEDICATED CHANNEL

4.2.1. Downlink DCH Open Loop Power Control

4.2.1.1.Downlink DCH Open Loop Power Control at Call set-up

At call set-up, the RNC creates a new link for a UE without any existing radio link. The downlink transmit power is derived using measurements reported by the UE and RNC parameters. In particular the RNC extracts from the RRC Connection Request message the primary measurement reported by the UE and then calculates the initial downlink transmit power according to (1)




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.ARGINDL_POWER_M /ICPICH_E - EcNoTarget

,P ,P

Min =power TX DL Initial

oc

Min

Max

+

Max (1)

Where • Initial DL TX Power is expressed in dB with respect to the P-CPICH power • PMin and PMax define the minimum and maximum allowed downlink transmitted

power for the considered radio bearer configuration. They are expressed in dB with respect to the P-CPICH power

• EcNoTarget is referred to the considered radio bearer configuration and expressed in dB.

• CPICH_Ec/Io is the primary measurement reported by the UE within the RRC Connection Request message and is expressed in dB upon proper mapping as specified in [6]

• DL_Power_Margin is a safety margin value allowing some change in the link budget between the time the measurement is performed and the time the radio link is actually active. It is expressed in dB

As described in [14] the UE in idle state receives the measurement quantity to be measured via SIB11 message broadcasted on the BCCH. In the case where there is no CPICH Ec/Io measurement available in the RRC Connect Request or the Cell Update message, the maximum allowed transmit power level should be set to PMax.

4.2.1.2.Downlink DCH Open Loop Power Control in Cell_DCH state

When the RNC adds a new radio link to existing ones (i.e. UE in Cell_DCH state moves into soft/softer handover mode), the NodeB transmit power is calculated according to (2).

Initial DL TX Power = PMin + Pnew_leg_offset (2) Where:

• PMin is the minimum downlink transmit power allowed at the NodeB on for the considered UE

• Pnew_leg_offset is an offset value read from the RNC MIB

The initial downlink transmitted power information is provided to the NodeB via NBAP signalling used during e.g. Radio Link Setup or Radio Link Addition procedures. Refer to [10] for more information. Once the NodeB receives any of these NBAP messages, it applies the given power on each downlink Channelization Code of the radio link when starting transmission. Upon




Page 23 of 23

reception of a Radio Link Addition Request message, if no initial downlink Transmission Power is included, the NodeB shall use the power level currently used for the considered UE.

4.2.1.3.Translation Settings

The parameters defined in chapters 4.2.1.1 and 4.2.1.2 are summarized in Table 17. The range of these parameters is indicated as well as their default value. Since the top object for all these parameters is UEGTFCS they can all be set with different values depending on the service combination supported in the downlink.

Parent Object

Parameter name Attribute Syntax & Range

UEGTFCS Instance

Default Value

Access

1, 2, 3, 4, 5, 6, 7, 9, 11,

13, 14

-19.0dB

31, 32, 33, 34, 35, 50, 51,52,54

-18.0dB

EcNoTarget (prev. slRTarget)

Real - [dB] -24.0, -23.9...+1.5

36, 49, 53 -15.0dB All +3dB dLPowerMargin Real - [dB]

-10, -9.9, …+10 13, 14 0 1, 2, 4, 5, 6, 7

9, 11 +5dB

DLDPCHInfo

newLegPowerOffset Real - [dB] 0, 0.1, ….25.5

All others +6dB

RNC-CLIRW-EL

Table 17: Downlink open loop power control parameters

4.3. OUTER LOOP POWER CONTROL FOR DOWNLINK DEDICATED CHANNELS

4.3.1. Downlink DCH Outer Loop Power Control Principle

The downlink Outer Loop Power Control is in charge of updating the SIRtarget in order to provide the Block Error Rate performances corresponding to the requested Quality of Service. This control loop runs autonomously in the UE with a maximum speed of 100Hz. The principle is depicted in Figure 2. The target is sent by the RNC to the UE via RRC signalling, using the downlink dedicated control channel. From this provided BLER value the UE derives the initial SIRtarget value. The instant BLER is continuously monitored and the SIRtarget is re-adjusted in order to ensure the requested quality is achieved in any radio channel scenario (speed, environment, … etc.). The method on how to set SIRtarget in order to provide the requested BLER is not specified in the 3GPP standard. The algorithm is specific to the terminal manufacturers. Minimal UE performances in given RF conditions are specified in [4].




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UE Node B

Link quality estimate:BER, BLER, SIR,channel, speed ...

InnerLoop

PCSIRtarget = f(link quality)

RNC

Pmax, Pmin= f(QoS, load)

BLERtarget,

Measurements:BLER, SIR

Overall Tx power,.

up/down

data

NBAP

NBAP

DCCH

DCCH

DL Outer Loop PC

Figure 2: Downlink outer loop power control principle

4.3.2. Translation Settings

The parameter defining the BLER target value is named bLERQualityTarget. This parameter is defined per radio bearer; i.e. one for downlink signalling, and one for downlink data service. The conversion between the real values provided in the OAM format and the typical values of the BLER is provided in (3) and (4). The basic information is reported in Table 18.

Parent Object Parameter name Attribute Syntax

& Range

Parent Object

Instances

Default Value Access

1 -2 (1%) 2, 3, 4 -2.1 (0.7%)

5 -3 (0.1%)

Dedicated TransportChannel

bLERQualityTarget Real -6.3, -6.2 … 0

All others -1.3 (5%)

RNC-CLI RW-EL

Table 18: Downlink Outer loop Power control - BLER target parameter

=

100Value Value %

10OAM Log (3)

OAMValue% 10100 Value ×= (4)

4.3.3. Outer Loop Power Control and User Elements

During optimization activities it has been observed that some UE’s have Outer Loop Power Control not properly working.




Page 25 of 25

This means that the SIRtarget is not updated according to the BLER measured on the downlink DCH, i.e. the Outer Loop provides SIRtarget values to the Inner Loop based apparently on a look-up table. This results in following issues:

• In good RF conditions (i.e. pilot Ec/Io better than –7dB) the UE requests higher downlink DCH power than required to maintain around 0-2% BLER which is lower than the BLERtarget of 5% defined via parameter bLERQualityTarget.

• In poor RF conditions, the SIRTarget is not increased in order to maintain the target BLER. As a consequence, the downlink BLER shoots up even if downlink DCH power is available.

• Irrespective of the downlink BLER calculated, the UE requests higher downlink power than required which leads to higher downlink DCH power consumption and reduced downlink capacity.

This misbehavior is strongly impacting the current setting for Uplink/Downlink Closed Loop power control parameters.

4.4. INNER LOOP POWER CONTROL FOR DOWNLINK DEDICATED CHANNEL

4.4.1. Downlink DCH Inner Loop Power Control Principle

The Inner Loop Power Control purpose is fast adaptation of the NodeB transmit power in order to achieve a targeted signal to interference ratio for the considered downlink radio channel. Because of the speed of the control loop (up to 1500 Hz), the only elements involved in the inner loop power control are the UE and the NodeB. Figure 3 describes the principle of downlink inner loop power control.

UE node B

TPC = Power_upor Power_down

transmit power=

f(TPC,deltaP, Pmin, Pmax,

....)

comparewith SIRtarget

SIR estimate

TPC

c

data

Figure 3: Downlink inner loop power control principle




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The Inner Loop Power Control procedures can be separated in four basic steps: 1. The NodeB transmits user data on the downlink DCH to the UE. 2. The UE performs the SIR estimation and compares the SIRest with the SIRTarget. 3. Depending on the results of the comparison, the UE uses a dedicated uplink

control channel conveying, the Transmit Power Control commands to the NodeB. The rate of these commands is up to 1500 Hz.

According to the information included in the TPC command, the NodeB decides to either increase or decrease its transmit power. Irrespective of the TPC commands the NodeB transmit power must remain within power ranges defined by [Pmin ; Pmax].

4.4.2. SIR Estimation and TPC Command Generation

For each received downlink DCH radio frame slot (2560 chip) the UE performs the SIR estimation. The measured value SIRest is the pilot bits of the DPCCH to noise ratio. The measurement technique is not specified in the 3GPP standard but is UE vendor specific. Some performance requirements are defined in [6]. Based on the SIRest value, the UE generates TPC commands according to the following rule: If SIRest >= SIRtarget Then TPC command = "0" [requesting a NodeB transmit power decrease] Else TPC command = "1" [requesting a NodeB transmit power increase]

4.4.2.1.TPC bit patterns

Depending on the slot format the TPC command may take one of two TPC bit patterns presented in Table 19. This bit pattern is derived from the Uplink DPCCH Slot Format information element transported in the Radio Link Setup Request and Radio Link Setup Reconfiguration NBAP messages.

.TPC Bit Pattern Transmitter power control command

NTPC = 1 (TPC_BIT_PATTERN = 0)

NTPC = 2 (TPC_BIT_PATTERN = 1)

1 0

11 00

1 0

Table 19:TPC bit pattern and transmitter power control command.

The relation between the slot format value and the TPC_BIT_PATTERN values, NTPC, are defined in Table 20 extracted from [1].




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Slot Format #i Channel Bit Rate (kbps)

Channel Symbol Rate (ksps)

SF NTPC NTFCI NFBI

0 15 15 256 2 2 0 1 15 15 256 2 0 0 2 15 15 256 2 2 1 3 15 15 256 2 0 1 4 15 15 256 2 0 2 5 15 15 256 1 2 2

Table 20:Slot format value and DPCCH fields

The TPC commands are sent in TPC field of the uplink DPCCH. Only slot format number 0 is used and therefore NTPC equal to 2 is always used with the corresponding TPC bit pattern. The reason to have only one slot format is due to the limited support of closed loop diversity (therefore no FBI bits is needed) and no support of uplink blind rate detection (therefore TFCI bits are always needed).

4.4.2.2.TPC pattern during Radio Link synchronization

When commanded by NBAP signalling, the TPC commands are sent on a downlink radio link from NodeBs that have not yet achieved uplink synchronization. These TPC commands follow a pattern as specified in the downlink TPC pattern 01 count IE. If the value included in the First Radio Link Set indicator IE indicates that the radio link is part of the first radio link set sent to the UE the following procedure applies:

• A value equal to n is obtained from the downlink TPC pattern 01 count IE; • The TPC pattern consists of n instances of "01" plus one instance of "1"; • The TPC pattern continuously repeat but is forced to re-start at the beginning of

each frame where CFN mod 4 = 0. Otherwise if the First Radio Link Set indicator IE indicates the radio link is not part of the first radio link set then the TPC pattern consists of all "1".

The TPC pattern terminates once uplink synchronization is achieved. If out of sync is detected at the NodeB after establishment of uplink synchronization, the downlink transmit power that has been supplied immediately before the detection of out of sync is held supplied if power balancing is set to “Off”. In the case power balancing is activated, the power is set to the reference power as defined in the NBAP power control message. If synchronization is established again, transmit power control is started according to the TPC bit pattern.




Page 28 of 28

From U03.03 onwards this will be a tunable parameter ranging from 0 to 255. The default value is 30 (i.e. corresponding to a speed of ~ 25dB/s). The value 0 is a special value used for the request of the alternance of "0" and "1" with no extra "1" at any time.

4.4.2.3.Downlink Inner Loop Timing

The standard does not specify the timing for the application on the downlink channel of the TPC commands received from the UE. Indicative information is provided in [2]. The decision for the timing of the update of the DPCH output power is left to each NodeB manufacturer. Discussion lead on Standard Committee level recommended that in the case of the downlink the inner loop power function should update the downlink DPCH output power in the NodeB at the start of the downlink pilot field. This would allow decoding the full TPC command received from the UE as illustrated in Figure 4. The SIR measurement periods illustrated here are examples; other ways of measurement are allowed to achieve accurate SIR estimation. If there is not enough time for the UTRAN to respond to the TPC, the action can be delayed until the next slot at the beginning of the next pilot field. To be noticed that this mechanism of downlink inner loop timing has only non-tunable parameter.

Data2 Data1 Data1 TPC

Data1 T P C

PILOT PILOT

PILOT

Response To TPC

TPC

DL SIRmeasurement

PILOT TFCI TPC

DL-UL timing offset (1024 chips)

Slot (2560 chips)

PILOT PILOT Data2 Data1 TPC

PILOT PILOT TFCI TPC

Slot (2560 chips)

Propagation delay

DL DPCCH at UTRAN

Propagation delay

DL DPCCH at UE

UL DPCCH at UTRAN

UL DPCCH at UE

512 chips

TFCI

TFCI

Figure 4: Downlink inner loop power control timing




Page 29 of 29

4.4.2.4.Downlink Inner Loop Power Control Modes

According to the first versions of the 3GPP standards Release ´99 [2], there are two downlink inner loop power control modes available: • “single TPC” the UE sends a unique TPC command in each slot and the TPC

command is transmitted in the first available TPC field in the uplink DPCCH. The power control speed is equal to 1500 Hz

• “TPC triplet” the UE repeats the same TPC command over 3 slots and the new TPC command is transmitted such that there is a new command at the beginning of the frame. The power control speed thus is reduced to 500Hz.

This power control mode is configured in the UE via RRC signalling messages, i.e. Radio Bearer Reconfiguration or Radio Bearer Set-up messages. More information is included in [7].


The parameter dPCMode defines the downlink power control mode and is a UE specific parameter controlled by the UTRAN. It is used to allow the UE to reduce the rate at which the NodeB adjusts its power. Since only “single TPC” mode is supported, this parameter has a fixed setting. More information on this parameter can be taken from Table 21. Parent Object Parameter

name Attribute Syntax

& Range UEGTFCS

Instance Default Value

Access

DLDPCHInfo DPCMode Enumerated (sINGLETPC)

All sINGLETPC RNC-CLI RW-EL

Table 21:Downlink power control mode parameter

4.4.3. Downlink Transmit Power Limits

4.4.3.1.Principle

Simulations have shown that in the case of non real time transfers, i.e. when the RLC mode is set to Acknowledge Mode, a capacity gain can be achieved by limiting the increased speed of the inner power control loop. The gain is achieved by limiting the transmit power peaks whilst the resulting errors are recovered by RLC retransmissions. The two following sections describe the expected behaviour from both the RNC and the NodeB in order to support this feature. The power increase limitation is a function that uses following set of parameters that are defined on a per cell basis:

• Power_Raise_Limit • DL_power_averaging_window_size




Page 30 of 30

Upon creation of a new cell, the C-RNC shall extract both the Power_Raise_Limit and DL_power_averaging_window_size OAM parameters from the cell OAM profile and populate the corresponding fields of the Cell Setup Request NBAP message with these values. No strategy involving the dynamic management of these parameters is foreseen for U03.03. The Radio Link Reconfiguration Request message can also support this information element but it is not supported in U03.03. The actual IE that triggers the activation of this function is the “Limited Power Increase” IE. More information can be taken from [10]. This parameter can take following values:

• Limited_Power_Increase_ACTIVE [True] • Limited_Power_Increase_INACTIVE [False]

The Limited_Power_Increase_xxACTIVE state is defined in the RNC on a per call basis. The default state value is always Limited_Power_Increase_INACTIVE If, as a result of the active set update procedure, the S-RNC adds initial radio links to a NodeB/D-RNC, the "Limited Power Increase" IE shall be populated according to the procedure described in the next chapter.

4.4.3.2.Transition between xx_inactive and xx_active states

Limited Power Increase is activated when all the radio bearers mapped onto the radio link allow the use of this feature. This means that e.g. if a call supports a voice service, Limited Power Increase will not be allowed. In order to manage this requirement the boolean Limited_Power_Increase_Allowed OAM flag is defined on a per radio bearer basis. The RNC shall store the value of the parameter for each of the radio bearers of each ongoing call. When in Cell_DCH mode, upon creation or deletion of a radio bearer the RNC shall check the updated list of Limited_Power_Increase_Allowed flags associated with the call:

• If the call is in Limited_Power_Increase_INACTIVE state and all the Limited_Power_Increase_Allowed flags are set to allowed the call shall switch to Limited_Power_Increase_ACTIVE state and the RNC shall activate the Limited Power Increase function by setting the “Limited Power Increase” IE to used in the subsequent NBAP message sent to the NodeBs involved in the call.

• If the call is in Limited_Power_Increase_ACTIVE state and at least one of the Limited_Power_Increase_Allowed flags is set to not allowed the call shall switch to Limited_Power_Increase_INACTIVE state and the RNC shall de-activate the Limited Power Increase function by setting the “Limited Power Increase” IE to not used in the subsequent NBAP message sent to the NodeBs involved in the call.

When entering the Cell_DCH mode, the RNC shall check the Limited_Power_Increase_Allowed flag of each of the radio bearers mapped on the DPDCH:




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• If all the Limited_Power_Increase_Allowed flags are set to allowed the call shall switch to Limited_Power_Increase_ACTIVE state and the RNC shall activate the Limited Power Increase function by setting the “Limited Power Increase” IE to used in the subsequent Radio Link Setup Request NBAP message sent to the NodeBs involved in the call.

• If at least one of the Limited_Power_Increase_Allowed flags is set to not allowed the call shall be set to Limited_Power_Increase_INACTIVE state and the RNC shall either:

not populate, set to not used,

the “Limited Power Increase” IE to used in the subsequent Radio Link Setup Request NBAP message sent to the NodeBs involved in the call.

4.4.3.3.Downlink Inner Loop Power Control Algorithm and Execution

The algorithm is located in the NodeB and is used to update the transmitter power according to the TPC command received by the UE. For the k:th received TPC command TPCest(k), the NodeB adjusts the current downlink power P(k-1) to a new power P(k) according to (5).

P(k) = P(k-1) + PTPC(k) + Pbal(k) (5) where

• PTPC(k) is the k:th power adjustment due to the inner loop power control calculated in [dB] as follows:

If the value of Limited Power Increase is set to “False”

=−=+

=0)(TPCif∆1)(TPCif∆

)(PestTPC

estTPCTPC k

kk

(6)

If the value of Limited Power Increase is set to “True”

=−≥+=−<+=+

=0)(TPCif∆

__∆)(∆1)(TPCif∆__∆)(∆1)(TPCif∆

)(P

estTPC

TPCsumestTPC

TPCsumestTPC

TPC

kLimitRaisePowerkandkLimitRaisePowerkandk

k

(7)

where ∑

−

+−=

=1

1____TPCsum )(P)(∆

k

SizewindowAveragingPowerDLki

ik (8)

• Pbal(k) is a correction in [dB] according to the downlink power control procedure

for balancing radio link power towards a common reference power in soft/softer handover scenarios. The estimation of this parameter is described in following chapters.




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For the first (DL_Power_Averaging_Window_Size – 1) adjustments after the activation of the limited power raise method, formula (6) shall be used instead of formula (7). The NodeB shall store the value of the DL_power_averaging_window_size and Power_Raise_Limit parameters contained in the Cell Setup Request message received during the cell set up procedure. These parameter values are used each time a request for the activation of the downlink Power Increase Limitation function on one of the radio links supported by the cell is received. Upon reception of a Limited Power Increase IE set to “Used”, the NodeB shall activate for the related radio link(s) the Limited Power Increase function as described. In case of softer handover, all the softer legs associated with to the UE context shall be affected by the activation. Upon reception of a Limited Power Increase IE set to “not used”, the Node B shall de-activate for the related radio link(s) the Limited Power Increase function, if it is active. In case of softer handover, all the softer legs associated with the UE context shall be affected by the de-activation. In case of softer handover, the downlink requested transmit level shall be the same for all the softer legs. Therefore, the Limited Power Increase function shall be either active or inactive for the whole set of softer legs.

4.4.3.4.Downlink Inner Loop Transmit Power Step Size

The power step size is set by the RNC through an NBAP primitive. The value is conveyed by the “TPC DL step size” information element, which can only be found in the Radio Link Setup Request primitive. Upon reception of a TPC downlink step size information element the NodeB shall store and apply the new step size value when the message becomes effective. Upon creation of a radio link, if the TPC downlink step size IE is not available, the NodeB shall use the default value. Upon creation or reconfiguration of a radio link the RNC shall populate the TPC Downlink Step Size IE in the associated NBAP message with the value extracted from the OAM MIB table corresponding to the service profile mapped onto the downlink physical channel. The 3GPP standard states in [2] that it is mandatory for UTRAN to support TPC commands adjustments steps ∆TPC of 1dB, while support of 0.5, 1.5 and 2.0dB is optional. All the step sizes are supported in U03.03. The step size accuracy complies with the 3GPP requirements as described in [5]. These specify the transmitter power control step tolerance and the transmitter aggregate power control step range as described in Table 22 and Table 23 respectively.

Power control commands in the downlink

Transmitter power control step tolerance

0.5 dB step size 1 dB, 1.5dB and 2dB step size Lower Upper Lower Upper




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Up (TPC command "1") +0.25 dB +0.75 dB +0.5 dB +1.5 dB Down (TPC command "0") -0.25 dB -0.75 dB -0.5 dB -1.5 dB

Table 22: NodeB transmitter power control step tolerance

Power control commands in the downlink

Transmitter aggregated power control step range after 10 consecutive equal commands

0.5 dB step size 1 dB, 1.5dB and 2dB step size Lower Upper Lower Upper

Up (TPC command "1") +4 dB +6 dB +8 dB +12 dB Down (TPC command "0") -4 dB -6 dB -8 dB -12 dB

Table 23:NodeB transmitter aggregated power control step range


The parameter to which the Limited Power Increase IE is mapped is limitedDLPowerIncrease. The values for this parameter as well as for the powerRaiseLimit, dLPowerAvWindowSize and tPCStepSize are described in Table 24. Additionally, information on their range and access can be found in this table. Parent Object Parameter name Attribute Syntax

& Range Instances Default

Value Access

All others Y Dedicated Transport Channel

limitedDLPowerIncrease Boolean 2, 3, 4, 5 N

DLDPCHInfo

tPCStepSize Enumerated {TPC0-5 = 0.5, TPC1-0 = 1,

TPC1-5 = 1.5, TPC2-0 = 2}

All TPC1-0 RNC CLIRW-EL

powerRaiseLimit Integer [0,10]

- 10

LCell dLPowerAvWindowSize Integer

[1,60] - 15

OMC RO-SC,

RNC CLIRO-SC

Table 24: Downlink power control step size parameter

4.4.4. Downlink Dynamic Range

4.4.4.1.Downlink Transmit power limits from the NodeB

In [5] the requirements for the downlink power control dynamic range are specified. This range is defined as the difference between the maximum and the minimum transmit output power of a downlink channelization code for a specified reference condition and should be at least 18dB. Depending on the Power Amplifier configuration, the maximum output power is equal to 46dBm (i.e. 40Watt) or 43dBm (i.e. 20Watt) per carrier. Therefore, the minimum transmit power should be lower than 25dBm for a 20Watts NodeB and 28dBm for a 40Watts NodeB.




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4.4.4.2.Downlink Transmit power limits from the RNC

In order to restrict the downlink interference generated on one sector by one call, the RNC defines a maximum transmitted power level per radio link PMax. Similarly a minimum transmitted power level PMin is defined. This can be used to maintain the call at a level higher than the one required e.g. in a zone where coverage variations are very sharp and the call drop rate is high. In most cases however it is recommended to set the minimum downlink power level to the minimum code power value than can be achieved by the NodeB hardware. Once the NodeB receives these power limits via NBAP messages (i.e. Radio Link Setup Request or Radio Link Addition Request) it will not transmit with a level outside of the range defined by [PMin ; PMax]. This applies to the average power of the data part only, i.e. the DPDCH symbols. Transmitted DPDCH symbol means here a complex QPSK symbol before spreading, which does not contain DTX. More details are provided in [10].

4.4.4.3.Downlink Transmit Power Limits in Softer Handover

In the case where two or more sectors are in softer handover, the allowed dynamic range [Pmini, Pmaxi] of each sector i is therefore defined independently from one softer sector to the other. In order to avoid downlink imbalance within a set of softer radio links, the RNC requires that the initial downlink power level of any added radio link is the same as the one of the already existing links. This is achieved by not populating the “Initial DL Tx Power” IE in any Radio Link Addition Request NBAP message. Upon creation of a new radio leg, the RNC shall populate the Maximum downlink power and the Minimum downlink power IE of the Radio Link Setup Request NBAP message. The values to be used shall be those read from the OAM MIB table corresponding to the combination of radio bearers mapped onto the downlink DPDCH. If no Maximum downlink power IE is included in the NBAP message, the Maximum downlink power value stored for already existing Radio Links for this UE shall be applied. The same procedure is applied to determine the value of the Minimum downlink power if it is not present in the Radio Link Setup Request message.

4.4.4.4.Tuning of Pmax and Pmin

A correction factor is introduced in U03.03 to correct both Maximum DL power and Minimum DL power. These correction factors are OAM parameters defined on a per cell basis. They allow to fine tune Pmin and Pmax on per cell basis thereby making possible to solve or mitigate local cell planning issues. Upon creation of a new radio leg, the S-RNC shall populate the Maximum DL power and the Minimum DL power IEs of the Radio Link Setup Request and Radio Link Addition Request NBAP messages according to (9) and (10). Minimum DL power = Pmin + PminCorrectionFactor (9) Maximum DL power = Pmax + PmaxCorrectionFactor (10)




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Upon addition, deletion or reconfiguration of one or more of the downlink radio bearers that are mapped onto the physical channel, the RNC shall populate the Maximum DL power and the Minimum DL power IEs of the related Radio Link Reconfiguration message.

4.4.4.5.Translation settings

The translations of Pmax and Pmin are mapped into parameters maxDLPower and minDLPower respectively.




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& Range UEGTFCS Default Value Access

minDLPower Real - dB -35, -34.9 … +15

All -19dB

1, 2, 13, 50, 54

+3dB DLDPCHInfo maxDLPower Real - dB -35, -34.9 … +15

Others +6dB PminCorrection Factor

Real – dB -10.0, -9.9 … +10

- 0dB LCell

PmaxCorrection Factor

Real – dB -10.0, -9.9 … +10

- 0dB

RNC-CLI RW-EL

Table 25: Downlink Power Range Parameters.

To be noted that setting downlink DCH Power to 39dBm (i.e. 8Watt) results in having 40% of the Total Downlink Power assigned to a single user assuming that the UE requests most of the time the maximum allowed downlink DCH power to the NodeB. The basic settings for both transmit power limit parameters are included in Table 25.

4.4.5. Downlink power control in compressed mode

4.4.5.1.Impact of compressed mode on the Power Control function

The aim of downlink power control in downlink compressed mode is to recover as fast as possible a signal-to-interference ratio close to the EcNotarget after each transmission gap. In every slot during compressed mode except during downlink transmission gaps, the Node B shall estimate the kth TPC command and adjust the current downlink power P(k-1) [dB] to a new power P(k) [dB] according to (11)

P(k) = P(k-1) + PTPC(k) + PSIR(k) + Pbal(k) (11) where:

• PTPC(k) is the kth power adjustment due to the inner loop power control • PSIR(k) is the kth power adjustment due to the downlink SIRtarget variation • Pbal(k) [dB] is a correction according to the downlink power control procedure for

balancing radio link powers towards a common reference power. If no uplink TPC command is received because of uplink compressed mode gaps, the value PTPC(k) derived by the Node B shall be set to zero.




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Otherwise, PTPC(k) shall be calculated the same way as in normal mode but with a step size ∆STEP, as described in section 4.4.5.2, instead of ∆TPC.

4.4.5.2.DL power step size in compressed mode

The power control step size ∆STEP shall take the value of ∆RP-TPC during RPL slots after each transmission gap and ∆STEP shall take the value of ∆TPC otherwise, where:

• RPL is the recovery period length and is expressed as a number of slots. RPL is equal to the minimum value out of the transmission gap length and 7 slots. If a transmission gap is scheduled to start before RPL slots have elapsed, then the recovery period shall end at the start of the gap, and the value of RPL shall be reduced accordingly.

• ∆TPC is the power control step size in normal mode. • ∆RP-TPC is called the recovery power control step size [dB] and defined in (12).

. . 2

3Min =

TPC

∆∆ −TPCRP (12)

4.4.5.3.Calculation of PSIR(k)

The power offset is defined in (13).

( ) prevcurr PP δδ −=kPSIR (13)

where δPcurr and δPprev are respectively the value of δP in the current slot and the most recently transmitted slot and is computed according to (14)

( ) codingPcodingP _2_1sionPn_compres , ... sion,P1_compresMax P ∆+∆+∆∆=δ (14) where

• n is the number of different TTI lengths amongst TTIs of all TrChs of the CCTrCh • ∆P1_coding and ∆P2_coding are computed from the uplink parameters

DeltaSIR1, DeltaSIR2, DeltaSIRafter1, DeltaSIRafter2 as defined in (15) and (16).

• ∆Pi_compression is defined by (17).

• ∆P1_coding = DeltaSIR1 if the start of the first transmission gap in the transmission gap pattern is within the current frame.

(15)




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• ∆P1_coding = DeltaSIRafter1 if the current frame just follows a frame containing the start of the first transmission gap in the transmission gap pattern.

• ∆P1_coding = 0 dB in all other cases

• ∆P2_coding = DeltaSIR2 if the start of the second transmission gap in the transmission gap pattern is within the current frame.

• ∆P2_coding = DeltaSIRafter2 if the current frame just follows a frame containing the start of the second transmission gap in the transmission gap pattern.

• ∆P2_coding = 0 dB in all other cases.

(16)

• ∆Pi_compression = 3 dB for downlink frames compressed by reducing the spreading factor by 2.

• ∆Pi_compression = 10 log ( 15*Fi / ( 15*Fi -TGLi)) if there is a transmission gap created by puncturing method within the current TTI of length Fi frames, where TGLi is the gap length in number of slots ( either from one gap or a sum of gaps) in the current TTI of length Fi frames.

• ∆Pi_compression = 0 dB in all other cases.

(17)

In case several compressed mode patterns are used simultaneously, a δP offset is computed for each compressed mode pattern and the sum of all δP offsets is applied to the frame. The PSIR(k) results in Node B raising its power during the compressed slots in a frame containing idle period in order to compensate the raised DL EcNo target (SIRtarget_CM) by UE.

4.4.5.4.DL transmit power range aspects

For all time slots except those in transmissions gaps, the average power of transmitted DPDCH symbols over one timeslot shall not exceed Maximum_DL_Power [dB] by more than δPcurr, nor shall it be below Minimum_DL_Power [dB].

4.4.5.5.Impact of DL compressed mode on the behavior of the UE




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The UE behavior is the same in compressed mode as in normal mode, i.e. TPC commands should be generated based on the comparison of DL EcNoestimate and DL EcNotarget. However an alternative EcNo target value is used in the radio frames where the compressed mode idle period takes place. The SIR target value is computed every radio frame and is defined in (18).

SIRnormalettCMett DeltaSIRSIR += _arg_arg (18) DeltaSIR is defined in (19).

( ) codingPcodingPDeltaSIR _2_1sionPn_compres , ... sion,P1_compresMax ∆+∆+∆∆= (19) where

• n is the number of different TTI lengths amongst TTIs of all TrChs of the CCTrCh,

• ∆P1_coding and ∆P2_coding are computed from the parameters DeltaSIR1, DeltaSIR2, DeltaSIRafter1, DeltaSIRafter2 signalled by RRC signalling.


With only one gap being used in U03.03, the relevant parameters are DeltaSIR1, DeltaSIRafter1. These parameters affect the DL/UL ILPC in the frames with transmissions gaps or the frames with gaps in previous frame. The default values are 0 dB but simulation/measurement results are required to assess BLER performance impact of DeltaSIR1/after1 parameters. The corresponding translation settings are described in Table 26.

Parent Object Parameter name Attribute Syntax & Range

UEGTFCS Instance

Default Value

Access

deltaSIR1 Integer – [dB] 0, 0.01, 3

0

deltaSIRAfter1 Integer – [dB] 0, 0.01, 3

0


0 Transmission GapPattern


All

0

RNC-CLIRW


4.4.6. Power Imbalance

4.4.6.1.Introduction

In some conditions the TPC command detection error rate becomes high on the weakest link of a connection. When such a TPC error occurs, the TPC command is interpreted as a “Power_Up” (wrong value) whilst on the other leg(s) it is interpreted as a “Power_Down”




Page 40 of 40

(correct value); this results in downlink DCH power levels diverging by twice the power adjustement step size (e.g. 2dB). The next time an error occurs, the weakest leg may diverge by an extra 2dB or converge back if the errors cancel each other. As a result the involved sector transmits with a higher power than needed. This leads to a random walk effect for the transmit power of this link, and therefore there is a non-negligible chance that their downlink transmission power reaches much higher level than needed.

This effect is known as power imbalance. An example is depicted in Figure 5. The variations in downlink Transmitted Code Power of two legs in soft handovers is caused by power imbalance. Power imbalance can also happen when one of the transmit legs has a maximum transmit power value lower than the other legs. In such cases, the power up TPC commands may be ignored on this leg whilst the TPC down commands would result in power decrease. Power imbalance does not deteriorate the performance of the “imbalanced” links; it may improve it slightly. The main issue is that the overpowered transmission pollutes unnecessarily the other radio links in the vicinity, thus leading to a lower radio network capacity. In order to correct power imbalance, the transmit power balance procedure is used.

Figure 5: Downlink Power Imbalance Effect in Soft Handover Scenario.

The NodeB shall be able to support downlink Power Control procedures initiated by the C-RNC at any time when the NodeB communication context exists, irrespective of other ongoing C-RNC initiated dedicated NBAP procedures towards this NodeB communication context. The only exception occurs when the C-RNC has requested the deletion of the last radio link via this NodeB, in which case the downlink Power Control procedure shall no longer be initiated.




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4.4.6.2.Power Balance Procedure at the RNC

The transmit power balance procedure is triggered by the S-RNC which requests to all the NodeBs involved in the active legs of a connection to activate a process that makes sure that the downlink power level of the weakest links does not shoot up to some unwanted level. From a RNC perspective, the Imbalance Correction procedure for a given UE shall be activated or deactivated at the S-RNC by setting the Imbalance Correction parameter in the RNC MIB either to “Active” or “Inactive”. There shall be one Imbalance Correction MIB parameter per downlink Radio Access Bearer combination, i.e. one for Standalone Signalling, one for Voice + Signalling, etc ... There shall be also one downlink reference Power, Adjustment Period, Adjustment Ratio and Max Adjustment Step parameters per downlink Radio Access Bearer combination. The activity or inactivity of Imbalance Correction does not depend on the number of active radio legs.

4.4.6.2.1. Activation of the Imbalance Correction

The activation of the Imbalance Correction for one particular UE shall occur either: • At the call set up • Upon modification of the number of radio bearer services multiplexed onto the

physical channel. Upon modification of the number of radio bearer services of an ongoing call where Imbalance Correction is “inactive”, or at call setup, the S-RNC shall check the Imbalance Correction MIB parameter associated with the configuration which is about to be activated. If the Imbalance Correction is set to “Active”:

• The S-RNC shall trigger an Imbalance Correction activation procedure by sending a Downlink Power Control Request message to every NodeB connected to the S-RNC and supporting one or more radio links involved in the call. If the call involves one or more D-RNC, one message shall also be sent to each of these D-RNC (one per D-RNC).

• The downlink reference Power, Adjustment Period, Adjustment Ratio and Max Adjustment Step used in the related signalling message shall correspond to those of the new setting in the RNC MIB.

• The Power Adjustment Type IE shall be set to “Common” • Imbalance Correction shall then be considered to be active for that call.

4.4.6.2.2. De-activation of the Imbalance Correction

The de-activation of the Imbalance Correction for one particular UE only occurs upon modification of the number of radio bearer services multiplexed onto the physical channel.




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Upon modification of the number of radio bearer services of an ongoing call where Imbalance Correction is active the S-NRC shall check the Imbalance Correction MIB parameter associated with the configuration, which is about to be activated. If the Imbalance Correction is set to “Inactive”:

• The S-RNC shall trigger an Imbalance Correction de-activation procedure by sending a downlink power control request message to every NodeB connected to the S-RNC and supporting one or more radio links involved in the call. If the call involves one or more D-RNC, one message shall also be sent to each of these D-RNC (one per D-RNC).

• The Power Adjustment Type IE shall be set to “none”. • Imbalance Correction shall then be considered to be inactive for that call.

4.4.6.2.3. Reconfiguration of the Imbalance Correction

The reconfiguration of the Imbalance Correction parameters for one particular UE only occurs upon modification of the number of radio bearer services multiplexed onto the physical channel. Upon modification of the number of radio bearer services of an ongoing call where Imbalance Correction is active, the S-NRC shall check the Imbalance Correction MIB parameter associated with the configuration which is about to be activated. If the Imbalance Correction is set to “Active':

• The S-RNC shall trigger an Imbalance Correction activation procedure by sending a downlink power control request message to every NodeB connected to the S-RNC and supporting one or more radio links involved in the call. If the call involves one or more drift RNC, one message shall also be sent to each of these drift RNCs (one per drift RNC).

• The downlink reference Power, Adjustment Period, Adjustment Ratio and Max Adjustment Step used in the related signalling message shall correspond to those of the new setting in the RNC MIB.

• The Power Adjustment Type IE shall be set to “Common' • Imbalance Correction shall be considered to remain active for that call

4.4.6.3.Imbalance correction at the Drift RNC

In the case where it acts as a D-RNC, the RNC has to support Imbalance Correction requests from the S-RNC in both “individual” and “common” mode. That is for the case where the S-RNC is a non-Lucent Technologies product and it requires the use of BTP in “individual” mode. At the creation of a UE context and prior to the reception of any downlink power control request RNSAP message, the D-RNC shall set its Imbalance Correction parameters to the following default values:




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• Power Adjustment Type = “none” • DL Reference Power = 0 • Max Adjustment Step = 1 • Adjustment Period = 1 • Adjustment Ratio = 0

Upon reception of a downlink power control request RNSAP message from the S-RNC with Power Adjustment set to any value, the D-RNC shall store the new Power Imbalance Correction parameters values in the related UE context. In the case where the “Power Adjustment Type” IE of the message is set to “common” or “none”, the D-RNC shall forward a copy of the "DL Power Control" RNSAP message to each NodeB involved in the call and connected to the D-RNC via a downlink power control request NBAP message. In the case where the D-RNC is aware that a NodeB is already in "none" mode, it shall not forward towards that NodeB any subsequent "DL Power Control" RNSAP message containing a Power Adjustment Type IE set to “none”, unless the “DL inner loop PC status” IE requires a change from the current "inner loop PC status" value for the call. At Radio Link Setup the BTP mode shall be assumed to be “none” and the “DL inner loop PC status” mode is provided in the “RL Setup Request” RNSAP message. In the case where the “Power Adjustment Type” IE of the message is set to “individual”, the D-RNC shall also forward a copy of the "DL Power Control" RNSAP message to each NodeB involved in the call and depending of it via a downlink power control request NBAP message. Note, that if there is more than one radio link on a NodeB, which is in the "individual" list, the RNC shall send only one message to that NodeB and that message should contain the list of all the radio links on that NodeB listed in the RNSAP message.

4.4.6.4. Estimation of Pbal

If power balancing is active on a radio link, the power balancing adjustment is superimposed on the inner loop power control adjustment as described in (20). The accuracy should be of ±0.5 dB.

))(1( initCPICHPrefbal PPPrP −+−= −∑ (20)

Where:

• The sum is performed over an adjustment period corresponding to a number of frames equal to the value of the Adjustment Period IE,

• Pref is the value of the DL Reference Power IE,




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• PP-CPICH is the power used on the primary CPICH, • Pinit is the code power of the last slot of the previous adjustment period and • r is given by the scale Adjustment Ratio IE.

4.4.6.5.Limitation at the NodeB

The RNC does not wait for the radio link to establish uplink synchronization to send the downlink power control request message to the NodeB. At call setup, if the Imbalance Correction is applied before closed loop power control synchronization is achieved, the odds are very high that the downlink power level will converge towards Pref (which is usually a low power level) and the call setup procedure will fail. As a workaround for this issue, the following implementation is required to the NodeB for U03.03.

• For the radio links established with a Radio Link Setup Request message containing a “First RLS indicator” IE set to “true”, the NodeB shall delay the application the downlink power balance corrections Pbal until the uplink has reached synchronization.

• For the radio links established with a Radio Link Setup Request message containing a “First RLS indicator” IE set to “false”, the downlink power balance corrections Pbal shall be applied immediately after reception of the downlink power control request message, and independently of the uplink synchronization status. The power adjustments shall be started at the first slot of a frame with CFN modulo the value of Adjustment Period IE equal to 0, shall be repeated for every adjustment period and restarted at the first slot of a frame with CFN equal to 0, until a new downlink power control request message is received or the RL is deleted.

The algorithm presented in Figure 6 is used for application of the correction at the NodeB level.




Page 45 of 45

CFN = 0?or

CFN mod Adjustment Period = 0?

begining of a new radio frame?

Period_Correction = (1-r) (Pref + PCPICH - Pinit)Already_Corrected = 0

Pbal = sgn(Period_Correction ) x min(1/ Max Adjustment Step ,

abs(Period_Correction - Already_Corrected))

Already_Corrected = Already_Corrected + Pbal

new timeslot

yes

yes

no

no

Figure 6 Downlink Power Balance Algorithm at NodeB level

Upon reception of a downlink power control request message: • If the value of the Power Adjustment Type parameter is “Common”, the Power

Balancing Adjustment Type of the NodeB Communication Context shall be set to “Common”. As long as the Power Balancing Adjustment Type of the NodeB Communication Context is set to “Common”, the NodeB shall perform the power adjustment for all existing and future radio links associated with the context identified by the NodeB Communication Context ID IE and use a common downlink reference power level.

• If the value of the Power Adjustment Type IE is “Individual”, the Power Balancing Adjustment Type of the NodeB Communication Context shall be set to “Individual”. The Node B shall perform the power adjustment for all radio links addressed in the message using the given downlink Reference Powers per radio link. If the Power Balancing Adjustment Type of the NodeB Communication Context was set to “Common” before this message was received, power balancing on all radio links not addressed by the downlink power control request message shall remain to be executed in accordance with the existing power balancing parameters which are now considered RL individual parameters. Power balancing will not be started on future radio links without a specific request.




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• If the value of the Power Adjustment Type IE is “None”, the Power Balancing Adjustment Type of the Node B Communication Context shall be set to “None” and the Node B shall suspend on going power adjustments for all radio links for the UE Context.


The parameters involved in the downlink power imbalance correction and described in the previous chapters are presented in Table 27.

Parent Object


UEGTFCS Instance

Default Value

Access

ImbalanceCorrection Bolean All Y maxAdjustmentStep Integer

[1, …10] slots All 2

adjustmentPeriod Integer [1, 2, … 256] frames

All 1

scaleAdjustmentRatio Integer [0 … 100]

All 50

1 10dB 2, 13, 50, 54 -20dB

3, 4, 6, 10, 31, 47, 51

-14dB

5, 7, 33, 36, 49, 53

-8dB

14 -17dB 9, 32, 34, 35,

48, 52 -11dB

DLDPCHInfo dLReferencePower Real – [dB]

[-35, -34.9…+15]

11 -10dB

RNC-CLIRW-EL

Table 27: Imbalance Correction Parameters

4.4.7. Power Offset between Downlink DPCCH and its DPDCHs

4.4.7.1.Principle

The downlink transmit power control procedure controls simultaneously the power of a DPCCH and its associated DPDCHs. The power of the different channels is adjusted in a way that keeps the relative power difference between DPCCH and DPDCH constant. Figure 7 depicts the single slot structure of a downlink DPCH including the different power offsets. The power levels of TFCI, TPC and pilot fields of the DPCCH are defined as offsets relative to the DPDCHs power by PO1, PO2 and PO3 [dB] respectively.




Page 47 of 47


TPC NTPC bits



Data2 Ndata2 bits

DPDCH

TFCI NTFCI bits

Pilot Npilot bits

Data1 Ndata1 bits

DPDCH DPCCH DPCCH

PO2 PO1 PO3

Figure 7: Power offsets in downlink DCH.

These values are set by the S-RNC, which reads the values from the OAM managed tables. Upon reception of the related NBAP messages (Common Transport Channel Setup Request / Radio Link Setup Request) the NodeB applies the requested downlink power offset to the relevant DPCCH block. To be noticed that PO1 and PO3 can be signaled to the NodeB only at Radio Link Setup ([10]). This means that they cannot be modified once the radio link is set up. PO2 can be modified only through DCH Framing Protocol signalling as defined in [9]. Based on the BLERtarget sent by the RNC for the downlink DCH, the UE is able to deduce, through the Outer Loop procedure, a SIRtarget for the data part, but not for the pilot part. In order to calculate the SIRtarget for the pilot, the UE needs to add up the power offset PO3 between pilot field and data field. This is achieved via RRC signalling on the FACH as described in details in [7].

4.4.7.2.Impact of PO1 and PO3 on the radio link

In marginal conditions, increasing the value of PO1 may help to improve the BLER performance by reducing the probability of TFCI decoding errors. Note that only one TFCI per radio frame has to be decoded so the probability to fail is relatively small. Otherwise if the TFCI decoding fails the whole radio frame will be discarded. Increasing PO3 could help the UE to achieve synchronization and consequently its receiver to perform better at a given SIR set point, thus leading to downlink capacity gain.

4.4.7.3.Dynamic management of the downlink power offset PO2 4.4.7.3.1. Introduction

Experience with IS95 networks showed that the radio link quality is substantially enhanced when the power offset between the data and the TPC parts of the downlink frame increases with the number of radio link sets connected to the UE. The same strategy has been ported to the UMTS context. Three parameters are defined in the RNC MIB for each service combination supported:




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• PO2_for_one_RL_set when the number of Radio Link Active Sets is equal to 1 • PO2_for_two_RL_set when the number of Radio Link Active Sets is equal to 2 • PO2_for_three_RL_set_and_more when the number of Radio Link Active Sets is

equal to 3 and more. These values shall be passed to the TPU at call set up and each time a new service is added or removed on the downlink. This is achieved through DCH FP signalling, using the Radio Interface Parameter Update message as described in [9]. The PO2 field in the NBAP/RNSAP Radio Link Setup Request message is mandatory. Unfortunately, the serving RNC only knows the number of RLS after reception of the subsequent Radio Link Setup Response message. Therefore when it prepares the Radio Link Setup Request message, the S-RNC cannot determine which one of the PO2_xxx parameters it should use. Therefore the S-RNC populate always the PO2 IE in any NBAP/RNSAP Radio Link Setup Request message with the value of the “PO2_for_one_RL_set” corresponding to the related service profile. Once the transport bearer of the new Radio Link has established synchronization, the RNC shall calculate the number of Radio Link sets and subsequently using the Radio Interface Parameter Update DCH Framing Protocol message:

• Update PO2 for the newly created RLS if only this RLS requires to be updated • Update PO2 for all the RLS involved in the call, if they all require an update • Perform no PO2 update, if none is required.

4.4.7.3.2. Algorithm to determine the value of the PO2 field

The S-RNC will determine the value of the PO2 field according to following cases. PO2 is populated with the value PO2_for_one_RL_set when either:

• The number of radio link sets decrease and is equal to 1. • PO2_for_one_RL_set has been updated at the RNC and the number of RLS is 1

PO2 is populated with the value PO2_for_two_RL_set when either: • The number of radio link sets changed and is now equal to 2. • PO2_for_two_RL_set has been updated at the RNC and the number of RLS is 2.

PO2 is populated with the value PO2_for_three_RL_set_and more when either: • The number of radio link sets increase and is equal to 3. • PO2_for_three_RL_set_and more has been updated at the RNC and the number of

radio link sets is equal to 3 or more.


Each of the parameters defining the power offsets can be defined with different values depending on the selected downlink service combination specified through different instances of top object UEGTFCS.




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UEGTFCS Instances

Default Value

Access

pO1 Real - [dB] (0.0, 0.25…,6.0)

All 0dB

pO2ForOneRLSet Real- [dB] (0.0,0.25…,6.0)

All 0dB

pO2ForTwoRLSet Real- [dB] (0.0,0.25…,6.0)

All 3dB

pO2ForThreeRFSetAndMore

Real- [dB] (0.0,0.25…,6.0)

All 6dB

DLDPCHInfo

pO3 Real- [dB] (0.0,0.25…,6.0)

All 2dB

RNC-CLI RW-EL

Table 28: Downlink DCH power offsets parameters.

During lab optimization tests as well as in the field setting of pO3 parameter equal to 2dB has been validated for all supported service combinations. This setting helps to minimize random walk issues as well as to solve issues related to loss of downlink synchronization observed before the DPCH power reaches the upper limit. The default values of these power offsets are included in Table 28.

4.4.8. Deactivation of the downlink ILPC

The downlink Inner Loop Power Control can be deactivated at the NodeB for a group of radio links belonging to the same Node B communication context. This is achieved by the use of the Inner Loop downlink power control IE in the NBAP / RNSAP downlink Power Control Request message. There is no possibility of disabling the Inner Loop Power Control on one Radio Link and keep active the other Radio Links of the same NodeB-UE context. This feature is not expected to be used in the Lucent Technologies RRM strategy. However the message could be generated by a non-Lucent Technologies Drift-RNC or could be of some use for test purposes. For these reasons, the IE needs to be supported on the Iub / Iur interface and “DL ILPC inactivation” needs to be supported at the Node B. The S-RNC shall never populate the Inner Loop Downlink Power Control Status IE in the downlink power control request message. Upon reception over the Iur of a downlink power control request the C-RNC shall forward it to the Node Bs involved in the call If the S-RNC is a non-Lucent Technologies RNC, it may or may not have populated the Inner Loop downlink Power Control Status IE. If the IE is present, it shall be replicated in the downlink power control request message sent to the NodeB(s). If the NodeB receives a downlink power control request Message and the Inner Loop downlink Power Control Status IE is

• Present and set to “Inactive “, the NodeB shall deactivate inner loop downlink power control for all radio links for the Node B communication context.

• Set to “Active “, the NodeB shall activate inner loop downlink power control for all radio links for the NodeB communication context.

Note that [2] defines that the new power P(k) is to be calculated as follows:




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• Deactivation of downlink power control for a radio link shall be accomplished by excluding the component PTPC(k) from (6) and (7). All other components in this equations remain unaffected, especially the power imbalance correction function Pbal(k).

The parameter used to activate / deactivate the inner loop power control is described in Table 29.

Parent Object


UEGTFCS Instances

Default Value

Access

DLDPCHInfo innerLoopPCStatus Boolean All Y RNC-CLIRW-EL

Table 29: Deactivation of the Inner Loop Power Control




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5. Power Settings for Downlink Common Channels

5.1. INTRODUCTION

Following downlink physical common channels are supported: • Common Pilot Channel (CPICH) with sub-channels Primary CPICH (P-CPICH)

and Secondary CPICH (S-CPICH). • Primary Common Control Physical Channel (P-CCPCH): this channel is used to

carry the BCH. • Secondary Common Control Physical Channel (S-CCPCH): this channel is used

to carry the FACH and PCH. • Synchronization Channel (SCH) with two sub-channels the Primary SCH (P-SCH)

and the Secondary SCH (S-SCH). • Paging Indicator Channel PICH • Acquisition Indicator Channel AICH

To be noticed that S-CPICH is supported but not used in U03.x. Since in U03.03 only one S-CCPCH is supported, both PCH and FACH channels are multiplexed over this channel. More detailed information on downlink common channels can be found in [1].

5.2. POWER CONTROL PROCEDURES

The RNC controls the transmit power for all these channels. For all these channels except the FACH, there is no control loop. Therefore the transmit power values remain constant until the relevant RNC parameters are modified requiring a different transmit power. For the FACH channel, an open loop function can be implemented according to the specifications. This is not the case in U03.03. The power of the FACH channels is set to the maximum power allowed for this channel in the cell, i.e. the FACH channel is broadcast in the whole cell. The P-CPICH level is defined in dBm. The other downlink common channel power levels are defined in dB with respect to the P-CPICH level. This implies that when the P-CPICH level is modified the power level of the other downlink common channels is also modified accordingly. The configuration as well as the re-configuration (in case of changes in settings) of the transmit power of these downlink common channels is performed from the RNC by sending a Cell Setup Request NBAP message to the NodeBs to set the power of the p-SCH, S-SCH, S-CPICH and BCH channels. For the PICH and AICH, the level is set by sending a Common Transport Channel Setup Request NBAP message. All these NBAP procedures are described in detail in [10]. In the following sections a description of the downlink common channels as well as proper recommendation on the power settings are provided.




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5.3. COMMON PILOT CHANNEL AND SYNCHRONIZATION CHANNEL POWER

The P-CPICH is transmitted continuously and represents the power overhead consumed for this channel. Most descriptions give the pilot power as a ratio of the total output power of the amplifier (percentage). However the translation parameter is specified as absolute power in dBm to the system. The two synchronization channels are time multiplexed with the P-CCPCH having a duty cycle of 10% for one slot of 0.67ms. The power settings specified refer to a power on chip level and therefore must be multiplied with the duty cycle to get the real overhead powers for these channels. The power of the P-CCPCH, occupying the remaining 90% of each slot, can be specified separately.

Power P2

Power P1

Power P3

One frame (10 ms)

P-SCH:

S-SCH:

P-CPICH:

One slot (0.67 ms)

Figure 8: Frame and Slot Structure of CPICH, P-SCH and S-SCH.

Commonly both synchronization power settings are given relative to the pilot power setting. The powers P1 and P2 are equivalent to about 5% of the total amplifier power assuming a pilot power setting of 10%. To get the total overhead power of each channel the power must be multiplied by the duty cycle of 10% and thus only 0.5% of the total amplifier power is consumed for each channel (P-SCH and S-SCH). The corresponding translation parameters are provided in Table 30. All these parameter settings have a wide impact on the RF coverage as well as on basic procedures such as cell search (i.e. synchronization) and soft/softer handover. In particular the P-CPICH power should be set to a value that ensures proper RF coverage by achieving high success rate along synchronization procedures. On the other hand, too high power setting results in downlink capacity issues. The P-SCH and S-SCH power settings have to ensure high success rate along the different steps of the synchronization procedure as well as preserving system capacity though the impact is much lower than in P-CPICH case due to the low duty cycle of both channels. For this reasons current recommendations for these power settings are based on results observed along tests focused on synchronization procedures in different radio propagation environments and with different UEs.




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5.4. PRIMARY COMMON CONTROL PHYSICAL CHANNEL POWER

The P-CCPCH is the downlink physical channel used to carry the BCH transport channel. The BCH is used to broadcast information to the UE such as RRC System Information Broadcast and Master Information Block messages that includes several parameters used by the UE along idle mode procedures (e.g. RACH access and cell reselection) as well as connected mode procedures (e.g. soft/softer handover). More details on SIB and MIB procedures are provided in [7]. Figure 9 shows the frame structure of the Primary CCPCH.

Figure 9:Primary CCPCH Frame Structure.

The P-CCPCH is not transmitted during the first 256 chips of each slot. As each P-CCPCH slot consists of 2560 chips, the P-CCPCH duty cycle is equal to 90%. The power of the P-CCPCH is set through the parameter bCHPower defined with respect to the P-CPICH as presented in Table 30. Taking into account the 90% duty cycle if, e.g., P-CCPCH power is set to 30 dBm (i.e. 1 Watt or 5% of the 20W PA), the total overhead power is calculated as 90% of 1 Watt, hence it is equal to 0.9 Watt or 4.5% of the 20W PA. An optimal P-CCPCH power setting should ensure high success rate in decoding SIB and MIB messages at the UE while preserving system capacity in terms of downlink power available for Dedicated Channels. Along evaluation of achieving high decoding success rate, the time spent to decode the messages (that may consist of several Transport Blocks) as well as the time spent in decoding retransmitted messages due to CRC check failure have also to be taken into consideration. Theoretical assumptions as well as physical layer simulations have indicated that keeping BCH BLER target equal to 10% ensures the best trade-off between high decoding success rate (thus low decoding delay) and low power consumption.

5.5. SECONDARY COMMON CONTROL PHYSICAL CHANNEL POWER

The S-CCPCH is used to carry the FACH and PCH that are time-multiplexed. The FACH and the PCH channels are used to carry RRC signalling messages along, e.g., RRC Connection Establishment procedures and Paging procedures respectively. More details on these procedures are provided in [7].




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In general, as depicted in Figure 10 below, the S-CCPCH can support three different fields within its frame: the TFCI (unlikely the P-CCPCH), the data and the pilot. It is the UTRAN that determines if a TFCI should be transmitted, hence making it mandatory for all UE(s) to support the use of TFCI. Also the use of the pilot field is optional.




Data Ndata2 bits

TFCI NTFCI bits

Pilot Npilot bits

Figure 10:Secondary CCPCH Frame Structure.

When the FACH is active, DTX is enabled on the inactive channel (i.e. PCH) and vice versa. However due to the time-multiplexed structure of the FACH and PCH within S-CCPCH, there is no power saving at all if at least one of the two channels are active because the power on the data part within one Timeslot has to be the same. General optimization criteria for both FACH and PCH power settings should be based on minimizing the message error rate.


Data Ndata2 bits

TFCI NTFCI bits

Pilot Npilot bits

PO1 PO2

Figure 11: Power offsets in S-CCPCH.

Concerning FACH power settings optimization tests results have provided +4dB (i.e. 37 dBm) as the current recommended value to achieve BLERtarget of 15%. This value ensures higher decoding success rate of RRC Connection Setup message sent on the FACH along RRC Connection Establishment procedure, thus higher Network Attach as well as Call Set-Up Success Rate. This value results fairly high and in case high S-CCPCH power peaks it may occur that IAOC get activated even in medium load conditions and high BLER observed over periods longer than a UMTS frame due to IAOC. Separated power settings can be defined for FACH and PCH. The parameter k in Figure 10 and Figure 11 determines the total number of bits per downlink S-CCPCH slot. To be noted that TFCI bits are continuously transmitted but duty cycle is much lower than the one from the data field (i.e. FACH and PCH). The




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power levels of TFCI and pilot fields of the S-CCPCH can be defined as offsets relative to the power used in the data field (PCH or FACH) by PO1 and PO2 respectively. Figure 11 depicts the single slot structure of a S-CCPCH including the different power offsets. Increasing the value of the PO1 may help to improve the FACH/PCH BLER performance by reducing the probability of TFCI decoding errors. Increasing PO2 may help the UE to achieve synchronization and consequently perform a better reception of the S-CCPCH frame. Upon reception of the relevant NBAP messages the NodeB applies the requested downlink power offset to the relevant S-CCPCH block as described in [10]. The corresponding translations for power offsets PO1 and PO2 are presented in Table 30.

Figure 12:PICH Frame Structure.

5.6. PAGING INDICATOR AND ACQUISITION INDICATOR CHANNELS POWER

The PICH is a fixed rate (SF=256) physical channel used to carry the paging indicators. Figure 12 illustrates the frame structure of the PICH. One PICH radio frame of length 10 ms consists of 300 bits (b0, b1,…, b299). Of these, 288 bits (b0, b1 … b287) are used to carry paging indicators. The remaining 12 bits are not formally part of the PICH and are not transmitted. PICH is always associated with an S-CCPCH to which a PCH transport channel is mapped. Due to UE limitations PICH power settings have not been investigated in details; current default value is set to –5dB (i.e. 28 dBm). The AICH is a fixed rate (SF=256) physical channel used to carry Acquisition Indicators that corresponds to signature s on the PRACH. The phase reference for the AICH is the Primary CPICH. Figure 13 illustrates the structure of the AICH. The AICH consists of a repeated sequence of 15 consecutive access slots, each of length 5120 chips. Each access slot consists of two parts, an Acquisition-Indicator part consisting of 32 real-valued symbols a0, …, a31 and a part of duration 1024 chips with no transmission that is not formally part of the AICH. Optimization tests focused on RACH and AICH have verified that current default value equal to –5dB (i.e. 28 dBm) ensures high success rate of Acquisition Indication message received at the UE. The PICH is continuously transmitted with a duty cycle of 96% whereas AICH is transmitted only when RACH preambles need to be acknowledged.




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Figure 13:AICH Frame Structure.

Parameters pICHPower and AICHPower define the power setting of PCH and AICH respectively and are presented in Table 30.

5.7. DOWNLINK LOAD DUE TO COMMON CHANNELS POWER SETTINGS

In order to provide an indication on the power available for downlink dedicated channels, it is important to calculate the total downlink common channels load as a percentage with respect to the total downlink power defined by the PA size. Taking into consideration the Common Channels power settings and duty cycles described in previous sections, the total downlink Common Channels power (upon conversion in Watt) is equal to 8.7 Watts. This value is valid only if it is assumed that the FACH is always transmitted while PCH is inactive. In case of 20 Watts PA the total downlink Common Channels Load is given by following power ratio in Watts:

Total downlink Common Channels Load= 8.7/20 [Watts] = 43.5% This value is very high and definitely impacts the cell capacity when FACH is used. However taking into consideration that currently FACH power is transmitted only along call set-up or call re-establishment procedures (e.g. when RRC Connection Setup message is sent), re-calculation of total downlink Common Channels power without taking into consideration the S-CCPCH power results in 3.7 Watts. Therefore the downlink Common Channels load results:

Total DL Common Channels Load= 3.7/20 [Watts] = 18.5% This is the value that is normally assumed for Total downlink Load evaluation.




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5.8. TRANSLATION SETTINGS

Table 30 summarizes the different parameters involved in the power setting of the downlink common channels.

Parent Object


Default Value

Access

pCPICHpower Real – [dBm] -10, -9.9, …+50

+33.0dBm

pSCHpower Real - [dB] -35.0, -34.9, … +15.0

-3.0dB

sSCHpower Real - [dB] -35.0, -34.9, … +15.0

-5.0dB LCell

bchPower Real - [dB] -35.0, -34.9, … +15.0

-3.0dB

OMC RW-LO

RNC-CLIRW-LO

pCHPower Real - [dB] -35.0, -34.9, … +15.0

+4dB

pICHPower Integer - [dB] -10,-9.9, … +5

-5.0dB

SecondaryCCPCH. powerOffset1

Real - [dB] 0.0, 0.25, … 6.0

+0.0dB SCCPCH

Pch


Real - [dB] 0.0, 0.25, … 6.0

+0.0dB

fACHTrafPower Real - [dB] -35.0, -34.9, … +15.0

-5.0dB

fACHSigPower Real - [dB] -35.0, -34.9, … +15.0

+4.0dB


Real - [dB] 0.0, 0.25, … 6.0

+0.0dB SCCPCH

Fach


Real - [dB] 0.0, 0.25, … 6.0

+0.0dB

PRACH aICHPower Integer - [dB]

-22, -21.9, … +5 -5.0dB

OMC RW-PL

RNC-CLI RW-PL

Table 30: Power Settings for Downlink Common Channels




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6. Power Control for Uplink Dedicated Channels

6.1. UPLINK DEDICATED CHANNELS FRAME STRUCTURE

There are two types of uplink Dedicated Physical Channels DPCH, the uplink Dedicated Physical Data Channel (uplink DPDCH) and the uplink Dedicated Physical Control Channel (uplink DPCCH), which are I/Q code multiplexed within each radio frame as depicted in Figure 14. The uplink DPDCH is used to carry the Dedicated transport Channel. The number of uplink DPDCH transmitted per each radio link can vary. The uplink DPCCH is used to carry control information that consists of known pilot bits to support channel estimation for coherent detection, transmit power-control commands, feedback information, and an optional transport-format combination indicator. There is one and only one uplink DPCCH on each radio link.

Pilot Npilot bits

TPC NTPC bits

Data Ndata bits


Tslot = 2560 chips, 10 bits

1 radio frame: Tf = 10 ms

DPDCH

DPCCH FBI

NFBI bits TFCI

NTFCI bits

Tslot = 2560 chips, Ndata = 10*2k bits (k=0..6)

Figure 14: Frame structure for uplink DPDCH/DPCCH The parameter k in Figure 14 determines the number of bits per uplink DPDCH slot. More information concerning uplink DPCH are specified in [1].

6.2. INITIAL TRANSMIT POWER FOR UPLINK DEDICATED CHANNELS

At radio link establishment, an Uplink Dedicated Channel has to be set-up only at call set-up. The uplink DCH is set-up as soon as downlink DCH synchronization has been achieved. The DPCCH is always transmitted before the data part DPDCH. The initial transmit power for uplink DPCCH is determined by the open loop power control procedure. To delay the start of uplink DPDCH transmission, a power control preamble procedure can be used. In that case the transmission start between DPCCH and DPDCH is delayed.

6.2.1. Uplink DCH Open Loop Power Control

When establishing the first uplink DPCCH the UE sets the power level according to (21).




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DPCCH_Initial_power = DPCCH_Power_offset – CPICH_RSCP (21)

Where • DPCCH_Power_offset is a parameter in dB. • CPICH_RSCP is measured by the UE.

The reason to use uplink open loop power control is due to the high speed of uplink Inner Loop Power Control function. The UE calculates an initial transmit power value and once the new radio link has been synchronized, the inner loop power control function will make the uplink power converge.

6.2.2. Uplink DPCCH Power Control Preamble

During the call set-up phase, a Power Control Preamble can be used to make sure that the inner loop power control has converged before the actual start of the data transmission. This uplink DPCCH power control preamble is a period of Npcp uplink DPCCH radio frames transmitted prior to the start of the uplink DPDCH. The length Npcp of the power control preamble is a UE-specific parameter signaled by the RNC and can take the values between 0 and 7 radio frames. If the length of the power control preamble is greater than zero, the power control procedure used during the power control preamble differs from the ordinary power control that is used afterwards. After the first slot of the power control preamble, the change in uplink DPCCH transmit power is initially given by formula (22).

∆DPCCH = ∆TPC × TPC_cmd (22)

Where TPC_cmd is derived by the UE according to Algorithm1 for processing TPC commands (i.e. every timeslot) as described in 6.4.3.2. After the end of the uplink DPCCH power control preamble, the UE is expected to use the inner loop power control with one of the power control algorithms described in 6.4.3.3. Since the NodeB is not informed of the length of the Power Control Preamble period, the NodeB is designed to cope with the following requirements:

• The TFCI are filled with zeros during the PCP period as specified in [1]. • No transmission is done on the uplink DPDCH during the PCP period as specified

in [2]. The DPCCH power control preamble mode in the UE is configured by the RNC through RRC signalling as described in [7].




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The power offset defined in (21) can be set via parameter dPCCHPowerOffset. If power offset is set to high values this ensures a short synchronization time but may cause uplink power overshoot (as described in Figure 15) and result in an increase of the uplink interference. Otherwise if too low values are used, the uplink interference is minimized but synchronization time may take longer thus negatively impacting the call setup delay. Therefore optimal dPCCHPowerOffset parameter setting should ensure uplink power overshoot minimization without negative impact on call set-up delay. This needs to be verified in different RF scenarios as the initial uplink DPCCH power is calculated by the UE based also on RSCP measurements.

Figure 15:Uplink Transmitted Power with and without overshoot.

Several values have been tested for this parameter with different UE, in different RF conditions. A good compromise between overshooting and convergence time is achieved with a value of –84dBm. This does not avoid completely the overshooting (over 15dB were still measured in very good RF conditions) but some type of UE were not able to establish a connection to the network with lower values. Further testing need to be done to ensure –100dBm leads to an absence of overshoot and still good performances (Call Success Rate is 100%). The use of uplink DCH power control preamble is controlled using parameter pCPreamble. The basic information for these parameters is summarized in Table 31.


UEGTFCS Instance

Default Value

Access

ULDPCHInfo dPCCHPowerOffset Integer – [dB]

-164, -162…-6 All -84dB RNC-CLI

RW-EL




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pCPreamble Integer - 0..7 [Radio frames]

All 7

Table 31: Initial uplink power control related parameters.

6.3. OUTER LOOP POWER CONTROL FOR UPLINK DEDICATED CHANNELS

6.3.1. Uplink DCH Outer Loop Power Control Principle

The uplink Outer Loop Power Control is in charge of updating the SIRtarget in the NodeB in order to provide the Block Error Rate performances corresponding to the requested Quality of Service. The principle is depicted in Figure 16. This control loop runs in the RNC with a speed up to 100 Hz and may use various parameters to adjust the SIRtarget, such as:

• The quality estimate of the data received at the NodeB, • The number of soft legs, • The interference/load level in the uplink channel, • Measurement reports from the UE.

The new SIRtarget is then sent to the NodeB over the IuB/Iur links and is used by the inner loop function located in the NodeB as a reference against the SIRest,.

UE BTS

DCH quality estimate,CRC check reports

InnerLoopPC

RNC

Pmax, Pmin= f(QoS, load,

cell size)

inner loop algo,deltaTPC

up/down

data

NBAP

NBAP

DCCH

inner loop algo,

Measurements:RSSI, SIR...

DCH FP

UL outer Loop PC

DCH FPSIR targetupdate

Figure 16: Uplink outer loop power control principle

The method used to calculate the optimal SIRtarget value for providing the requested BLER is not specified in the 3GPP standards, where only a set of minimal NodeB performances for a set of given radio conditions is required (refer to [5]). The developed adaptation algorithm is Lucent Technologies proprietary and this approach involves a close interaction between the Radio Resource Management, the Call Admission Control, the Uplink Overload Control and the Outer Loop Power Control functions.




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6.3.2. Inter-RNC soft handover

In case of Inter-RNC soft handover the uplink Outer Loop Power Control function is located in the S-RNC, which will determine the SIRtarget for all the NodeBs involved in the connection. Figure 17 shows the location of uplink Outer Loop Power Control function within the different UTRAN Network Elements.

NodeB

NodeB

NodeB

NodeB

uplinkOLPC

Frameselector

Iub

Iur

Iub

Iub

Iub

Drift RNCServing RNC

ToCN

UE

Iu

Figure 17: Location of the uplink Outer loop function.

The Outer Loop Power Control procedures can be separated into following steps: 1. Radio link quality estimation: Each NodeB involved in the call performs an

estimation of the radio link quality on the uplink DCH; the results are provided to the S-RNC.

2. Frame selector function: the results of the radio link quality estimation are used by the Frame Selector function to provide unique quality estimation values to the outer loop power control algorithm.

3. Update of the SIRtarget: The outer loop power control algorithm uses the quality estimation values as well as other parameters to adjust the SIRtarget if required.

4. Update of the SIRtarget at the NodeB(s): The new SIRtarget value is sent to the involved NodeB(s) if required. Upon reception of this information, the NodeB applies the new SIRtarget to the related uplink Inner Loop Power Control function.

The information on the radio link quality estimation (uplink direction) as well as on the new SIRtarget (downlink direction) are transmitted using the DCH Framing Protocol.




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The DCH frames are transmitted every Transmission Time Interval whose values in general can be equal to 10, 20, 40 or 80 ms depending on the different radio channel coding.

6.3.3. Radio Link Quality Estimation

The radio link quality in the uplink can be estimated by the UTRAN using different metrics described in the 3GPP standards [3]. In the following the most relevant ones are presented and discussed.

6.3.3.1.BLER metric

The BLER metric is defined as the average error rate of transport blocks estimated on a transport channel containing a CRC check. The NodeBs send the result of the CRC check to the S-RNC over the Iub or the Iur interface, using the CRCI field of the DCH frames. For every transport block included in the data frame a CRCI bit is present, irrespective of the presence of a transport block CRC on the air interface. CRCI bit is set to “1” if CRC check failed and to “0” if either no CRC was present or CRC check passed. The BLER estimation is done after the frame selection by averaging the CRCI. Therefore this metric is computed at the S-RNC.

6.3.3.2.Quality Estimation metrics

The BLER is not an appropriate metric to evaluate the quality of transport channels with high quality requirements (e.g. BLERtarget = 10-3). Two alternative quality metrics are defined to refine estimate of the transport channel quality: the Transport BER and the Physical Channel BER. These metrics are computed at the NodeB and then forwarded to the S-RNC. More details can e found in [3].

6.3.3.2.1. Transport Channel BER metric

The Transport Channel BER is defined as the error rate of the DPDCH "bits" before decoding. The "bits" before decoding should actually be called symbols to avoid misunderstandings of the definitions. Using the above definition the "Transport Channel BER" is the SER for a given DCH. The detailed definition of the Transport Channel BER is provided in [3]. The "Transport Channel BER" is usually determined by decoding, re-coding and by comparing the re-coded symbols with the received symbols after hard-decision. The decoding and re-coding can be easily done for convolutional codes. At the point of time where the most-likely trellis path is selected, the output bit and the according input symbols are known. These symbols need to be compared with the input symbols to find the input symbols being in error. By counting the number of wrong symbols the Transport Channel BER can be determined. There is no unique mapping between the SER (bits in error before decoding) and the BER (bits in error after decoding). This mapping strongly depends on the radio environment and can change dramatically due to changes in the delay profile or UE speed. The Transport channel BER value is calculated within the range [0,1] and reported in the unit TrCh_BER_LOG as defined in [6]. The mapping between the measured quantity value and the reported value is included in Table 32. The defined range and resolution of




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the Transport Channel BER includes SER values of up to 100% while the expected value of the SER can't exceed 50% in a long term average. Thus, the high SER are quite unlikely to occur.

Reported value Measured quantity value TrCh_BER_LOG_000 Transport Channel BER = 0 TrCh_BER_LOG_001 -∞ < Log10(Transport Channel BER) < -2.06375 TrCh_BER_LOG_002 -2.06375≤ Log10(Transport Channel BER) < -2.055625 TrCh_BER_LOG_003 -2.055625 ≤ Log10(Transport Channel BER) < -2.0475 … … TrCh_BER_LOG_253 -0.024375 ≤ Log10(Transport Channel BER) < -0.01625 TrCh_BER_LOG_254 -0.01625 ≤ Log10(Transport Channel BER) < -0.008125 TrCh_BER_LOG_255 -0.008125 ≤ Log10(Transport Channel BER) ≤ 0

Table 32: Mapping of Transport Channel BER metric.

If the DCH FP includes transport blocks for the DCH, which was indicated as "selected" in the QE-selector IE, this Transport Channel BER is also mapped onto the Quality Estimation field of the DCH frame. If no Transport channel BER is available the QE field is then filled with the Physical channel BER. The conversion of the transport channel BER in the QE is performed using the formula (23). The reverse conversion is provided in (24). Many contributions to the 3GPP standards process have that the mean Transport Channel BER is not a reasonable measurement for estimating the BER or BLER after decoding.

==

≤<+

=

0 BERfor 0 QE

1 BER0for 255 0.008125

log10(BER)INT QE

(23)

==

≤<=

0 QEfor 0 BER

255 QE0for 0.008125* 10 255)-(QE BER

(24)

6.3.3.2.2. Physical Channel BER metric

The Physical Channel BER is defined as the bit error rate on the DPCCH This measurement has been included especially to provide quality information even if the DPDCH does not contain any data. As for the Transport Channel BER, the Physical




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Channel BER is related to the SER. The SER on the DPCCH can be measured by using the known pilot patterns, by decoding and re-coding of the TPC and TFCI information. The detailed definition of the Physical Channel BER is provided in [3]. The Physical channel BER is measured in the range [0,1] and reported in the unit TrCh_BER_LOG as defined in [6]. The mapping between the measured quantity value and the reported value is included in Table 33.

Reported value Measured quantity value PhCh_BER_LOG_000 Physical channel BER = 0 PhCh_BER_LOG_001 -∞ < Log10(Physical Channel BER) < -2.06375 PhCh_BER_LOG_002 -2.06375≤ Log10(Physical Channel BER) < -2.055625 PhCh_BER_LOG_003 -2.055625 ≤ Log10(Physical Channel BER) < -2.0475 … … PhCh_BER_LOG_253 -0.024375 ≤ Log10(Physical Channel BER) < -0.01625 PhCh_BER_LOG_254 -0.01625 ≤ Log10(Physical Channel BER) < -0.008125 PhCh_BER_LOG_255 -0.008125 ≤ Log10(Physical Channel BER) ≤ 0

Table 33: Mapping of Physical Channel BER metric

If the IE QE-selector equals "non-selected" for all DCHs in the FP frame, then the QE is the Physical channel BER. In case no Transport channel BER is available, then the QE is the Physical channel BER. The conversion of the physical channel BER in the QE is performed using the formula (23). The reverse conversion is provided in (24).

6.3.3.2.3. Translation settings

The parameter qESelector, described in Table 34, defines the mode to be included in the QE-selector IE in order to properly map the metrics in the QE field. The QE-selector IE is conveyed in NBAP or RNSAP messages during Radio Link Setup or Radio Link Reconfiguration procedure. Refer to [8] and [10] for more information. Current default value indicates that Physical Channel BER is the metric used for radio link quality estimation.




Page 66 of 66



& Range Parent Object

Instances Default Value

Access

All except 3 and 4 Y DedicatedTransportChannel

qESelector Boolean Y=”selected”,

N=”non-selected” 3 and 4 N

RNC-CLI RW-EL

Table 34: Metric selection parameter.

6.3.4. Frame Selector Function

Each NodeB k involved in the call performs CRC checks on each transport block. The resulting CRCIk and QEk are then sent to the S-RNC over the DCH-FP protocol. The Frame Selector uses the CRCIk and QEk values to estimate a CRCI and QE which are forwarded to the uplink outer loop power control algorithm.

6.3.5. Uplink Outer Loop Power Control Algorithm

6.3.5.1.Principle

The uplink outer loop power control algorithm uses the CRCI and QE values to evaluate if there is a need to re-adjust the SIRtarget. The information flow of the outer loop power control algorithm is depicted in Figure 18 assuming that the UE is in soft handover with two cells. In the RNC, the uplink outer loop function is made out one or more PHY entities. Each PHY entity is associated to one transport bearer (i.e. one DCH FP pipe). In the case where more than one DCH is associated to one transport bearer (e.g. “coordinated transport channels’), one single PHY entity is in charge of that group of coordinated transport channels. One example of coordinated transport channels is the case of the Voice Service where the 3 voice sub-flows are associated to one single DCH Framing Protocol pipe. Figure 19 gives an illustration of the uplink outer loop function for one call configured for “voice+64kPS+signalling” configuration. Each PHY entity can request an update of the uplink SIRtarget. This leads to the transmission of an uplink outer loop power control command to every NodeB involved in the call to update the uplink SIRtarget, as well as the re-synchronization of the SIR_calc values in the other PHY entities to that requested value.




Page 67 of 67

Frame Selector

CRCI, QE

OLPC

target SIR

ILPCa

est. SIR

SIR Estimator

Receiver

Decoder

ILPCa

est. SIR

SIR Estimator

Receiver

Decoder

target SIR target SIR

CR

CI 1

, Q

E 1

ILPCb

Transmitter

TX Pwr

TPCcmd1 TPCcmd2

UE

NodeB 2 NodeB 1

SRNC

CR

CI2, Q

E2

CRCI1, QE1 CRCI2, QE2

Figure 18:Information flow for Power Control based on CRC and QE

in soft handover scenario.




Page 68 of 68

PHY entityfor DCCH

PHY entityfor 64k PS bearer

PHY entityfor voice bearer

CRCI and QE information related toDCCH transport blocks

CRCI and QE information relatedto 64k PS transport blocks

CRCI and QE information relatedto voice transport blocks

Request for updateof UL SIR target



SIRcalcsync input

SIRcalcsync input

SIRcalcsync input

Generation of OUTER LOOP PCframes

(as per 25.427)

UL SIR target commands sentto BTS(s) involved in the call

UL outer loop function

sub flow#1, #2and #3

Figure 19: Uplink outer loop function for one call configured for “voice+64kPS+signalling’




Page 69 of 69

•


The parameters involved in the uplink outer loop power control algorithm are summarized in the Table 35 and Table 37. The parameters related to the SIRtarget initial value and limits are defined by translations initialSIRTarget, minSIRTarget and maxSIRTarget on a per service combination basis (e.g. PS data & signalling, standalone signalling, etc.) as they belong to the parent object UEGTFCS. This means that a new set of these parameters is passed on to the TPU each time a service is added or dropped from the call. In general optimized settings of these parameters can be derived according to the following rules:

• InitialSIRTarget needs to be slightly above the average SIR target set point • MinSIRTarget needs to be equal or slightly below the minimum observed target. • MaxSIRTarget needs to be equal or slightly above the maximum observed target.

Furthermore the optimal initialSIRtarget value should minimize the convergence time, hence the uplink power consumption & noise rise during the transient period, while the optimal minSIRTarget and maxSIRTarget values should ensure that standard deviation of measured uplink BLER around the defined target (e.g. 5%) is minimized as well as uplink power interference.

Parent Object Parameter Name Attribute Syntax & Range

UEGTFCS Instances

Default Value

Access

All Others +7dB 2 +5dB

3, 13, 14 +6dB

initialSIRTarget Real - [dB] -8.2, -8.1, … +17.3

47, 48, 49, 50, 51, 52,

53, 54

+8dB

All Except 3 0dB minSIRTarget Real - [dB] -8.2, -8.1, … +17.3 3 +4.9dB

All +8dB 2, 13, 14 +7dB

ULDPCHInfo

maxSIRTarget Real - [dB] -8.2, -8.1, … +17.3

31, 32, 33, 34, 35, 36

+9dB

RNC-CLI RW-EL

Table 35: SIR target related parameters

Experimental results showed that the performances are degraded by using lower values for qEThreshold. Therefore the decision on how to update the SIR_calc is based only on the CRC check results.




Page 70 of 70

Optimal settings of parameters downSIRStep and upSIRStep are strictly related to the uplink BLER target that has to be achieved on the considered uplink radio bearer. The uplink BLER target on a transport channel is related to the value of the upSIRStep and downSIRStep parameters by formula (25). During lab optimization different values of downSIRStep and upSIRstep have been tested, verifying whether the standard deviation of the uplink SIR target value at the NodeB is minimized, whilst maintaining the uplink BLER performance at around 5% for PS calls.

−

×=yTargetBLERQualit1

yTargetBLERQualitpdownSIRste upSIRstep (25)

In general increasing upSIRStep values may improve the reactivity of the control loop in highly variable radio environment, however that is to the detriment of its stability resulting in SIRtarget overshoots.

6.3.6. Outer Loop Power Control Execution

When the uplink outer loop power control function generates a new SIRtarget value, it is forwarded to the NodeB(s) involved in the connection to the UE. This information is sent over Iub or Iur interface depending of the relation of the NodeB to the S-RNC. The SIRtarget value is defined in dB with range [-8.2…17.3 dB] and step value of 0.1 dB. Its transmitted values are mapped to the unit UL_SIR_TARGET as in Table 36.

SIR Transmitted values SIR Used values UL_SIR_TARGET = 000 SIR Target = -8.2 dB UL_SIR_TARGET = 001 SIR Target = -8.1 dB UL_SIR_TARGET = 002 SIR Target = -8.0 dB … UL_SIR_TARGET = 254 SIR Target = 17.2 dB UL_SIR_TARGET = 255 SIR Target = 17.3 dB

Table 36: Mapping of SIRtarget values.

The mapping of the SIRtarget value need no synchronization between the different NodeB(s) involved in the radio connection. Upon reception of a DCH control frame with an outer loop power control field, the NodeB applies (i.e. within 10 ms) the new SIRtarget value to the related uplink inner loop power control function.


Parent Object

Instance

Default Value

Access

1, 3, 4 255.0 All others 130.0

qEThreshold Real 0.0, 1,0….255.0

19, 20, 21, 22,29

150.0

Dedicated Transport Channel

downSIRStep Real - dB 1 0.002

RNC-CLI RW-EL




Page 71 of 71

2, 5, 27, 28, 29

0.001

3, 4 0

0.000,0.001… 0.512

All others 0.01

All others 0.2 2 0.15

3, 4 0

upSIRStep Real - dB 0.000,0.001… 0.512

27, 28, 29, 30 0.02 sIRAllowance Real - dB

0,0.1….10 All 0

1 0.4 2 0.025

3, 4 0 8 0.2

SIRDownAdditional Real - dB 0.000,0.001… 0.512

All others 0.05 1, 6, 7, 9, 19 120

2, 3, 4, 27, 28,29, 30

250

5 200

NbOfConsecutive GoodFramesThreshold

IntType [0,1 .255]

20, 21, 22 160

Table 37: SIR calculation related parameters.




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6.4. INNER LOOP POWER CONTROL FOR UPLINK DEDICATED CHANNELS

6.4.1. Uplink Inner Loop Power Control Principle

The Uplink Inner Loop Power Control is adjusting the transmit power of the UE in order to achieve the SIRtarget provided by the outer loop power control function for a considered uplink dedicated channel. Due to the speed of the inner loop (up to 1500 Hz), the only elements involved are the UE and the NodeB. Figure 20 describes the principle of uplink inner loop power control.

Node BUE

transmit power=

f(TPC,deltaP, Pmin, Pmax,

....)

compare withSIRtarget

SIR estimate

TPC

data

TPC = Power_upor Power_down

c

Figure 20: Uplink inner loop power control principle.

The inner loop power control procedure can be separated in four basic steps:

1. The UE transmits the user data to the NodeB on an uplink DCH. 2. The NodeB performs the SIR estimation and compares the result with the SIRtarget. 3. If required, the NodeB will send the transmit power control commands to the UE

using the downlink DPCCH. The rate of TPC commands is up to 1500 Hz. 4. According to the transmit power control commands, the UE will either keep its

transmit power constant, or increase or decrease it by ∆TPC [dB]. Irrespective of the TPC commands the UE transmit power must remain within a range defined by [Pmin;Pmax].

6.4.2. SIR Estimation and TPC Commands Generation

6.4.2.1.SIR Estimation

The algorithm implemented in the UMTS Releases from Lucent Technologies to estimated the SIRest are based on explicit estimation where the signal energy and the noise variance are estimated.




Page 73 of 73

6.4.2.2.Transmit Power Control commands 6.4.2.2.1. TPC Generation

Based on the SIRest, the NodeB generates TPC commands according to the following rule: If SIRest >= SIRtarget Then TPC command = "0" [requesting a power decrease from the UE] Else TPC command = "1" [requesting an increase of the power at the UE]

6.4.2.2.2. TPC bit pattern

Depending on the downlink slot format, the TPC command may be transmitted over the air using one of the three TPC bit patterns described in Table 38 from [1]:

TPC Bit Pattern

NTPC = 2 NTPC = 4 NTPC = 8

Transmitter power control

command 11 00

1111 0000

11111111 00000000

1 0

Table 38: TPC bit pattern

The relation between the slot format value and the NTPC values can be found in [1]. The TPC commands are sent in TPC field of the downlink DPCCH.

6.4.2.2.3. TPC timing

According to the specifications, the UE is expected to change its uplink DPCH output power at the beginning of the first uplink pilot field after the reception of the TPC command, as illustrated in the Figure 21. The SIR measurement periods illustrated are examples; other ways of measurement are allowed to achieve accurate SIR estimation. If there is not enough time for the UE to respond to a TPC, the action can be delayed until the next slot at the beginning of the next pilot field. To be noticed that this mechanism of uplink inner loop timing has only non-tunable parameter. More information on the uplink power control timing can be found in [2].




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Data2 Data1 Data1 TPC

Data1 T P C

PILOT PILOT

PILOT

Response To TPC

TPC

PILOT TFCI TPC

DL-UL timing offset (1024 chips)

Slot (2560 chips)

PILOT PILOT Data2 Data1 TPC

PILOT PILOT TFCI TPC

Slot (2560 chips)

Propagation delay

UL SIRmeasurement

In response to TPC the UE changes the power accordingly

DL DPCCH at UTRAN

Propagation delay

DL DPCCH at UE

UL DPCCH at UTRAN

UL DPCCH at UE

512 chips

TFCI

TFCI

Figure 21: Uplink inner loop timing

6.4.3. Uplink Inner Loop Power Control Algorithms

6.4.3.1.Overview

In soft handover situations the UE may receive “up” commands on some legs and “down” command on others as depicted in Figure 22. In such case the UE should decrease its transmit power, unless there is a consensus amongst the cells in the Active Set for increasing it. The softer handover case is an exception. In that case all the involved links are requested to send back to the UE the same TPC command. The UE is informed via RRC Signalling and can perform some further combining enhancing the detection of the correct TPC word. Upon creation of a new link the UE is informed, if this new link will send the same TPC command as an existing one, by reading the TPC Combination Index IE. This is sent embedded in the Downlink DPCH info RRC message as described in [7]. If the value is the same as the one of an existing link, it implies for the UE that the TPC commands sent by the 2 radio links are identical and that it can apply the related algorithm for softer combining case. The RNC stores for each of the DCH that it is supporting the TPC combination index value of each one of the supported links. Upon creation of a new link in softer handover, the RNC sets the TPC combination index value of this new link to a value equal to the other links in softer handover.




Page 75 of 75

Figure 22: TPC received commands in soft/softer handover scenario

In the case a UE is in soft(er) handover, upon reception of the TPC commands in a slot, the UE derives a single TPC command, named TPC_cmd. There are two algorithm supported by the UE to derive its TPC_cmd value from the TPC it receives from the UTRAN. The RNC controls which one is used and configures the UE through RRC signalling. The value of PowerControlAlgorithm is extracted from a related MIB profile, which is manageable by OAM.

• If “PowerControlAlgorithm” indicates “algorithm1”, then the layer 1 parameter PCA takes the value 1 and algorithm 1 is supposed to be used.

• If “PowerControlAlgorithm” indicates “algorithm2”, then the layer 1 parameter PCA takes the value 2 and algorithm 2 is supposed to be used.

Note however that the behavior of the inner loop at the NodeB does not change upon the algorithm. It always sends one TPC word per slot and the TPC value depends on the comparison between SIRestimated and SIRtarget. Therefore the description of the two algorithms is provided as information. Only the method to configure the UE is to be specified from an UTRAN point of view.

6.4.3.2.Algorithm 1 for processing TPC commands

The first algorithm, “algorithm1”, is the basic inner loop algorithm running at a speed of 1500Hz. This algorithms works differently depending on which scenario the UE is involved in.

6.4.3.2.1. TPC command received when UE not in soft/softer handover

When a UE is not in soft handover, only one TPC command, either “0” or “1”, is received in each slot. In this case, the value of TPC_cmd is derived as follows: If TPC command = "0”




Page 76 of 76

Then TPC_cmd = "-1" Else TPC_cmd = "+1"

6.4.3.2.2. TPC commands received form links in softer handover

When the UE has the knowledge that some TPC commands received in a slot are the same, e.g. when in softer handover, the UE combines these N TPC commands into one single TPC_cmdsofter.

6.4.3.2.3. TPC commands received from links in soft combining

In the case the UE receives different TPC commands from links in soft handover, it conducts a soft symbol decision Wi on each of the power control commands TPCi, (i ∈ [1..N]), where N is the number of TPC commands from radio links of different radio link sets, that may be the result of a first phase of TPC combination. The UE derives a combined TPC command, TPC_cmd, as a function γ of all the N soft symbol decisions Wi:

TPC_cmd = γ (W1, W2, … WN), TPC_cmd can take the values “+1” or “-1” depending on the following:

• If the N TPCi commands are random and uncorrelated, with equal probability of being transmitted as "0" or "1", the probability that the output of γ is equal to “+1” shall be greater than or equal to 1/(2N), and the probability that the output of γ is equal to “-1” shall be greater than or equal to 0.5. This rule means that, regardless of the value of N, the probability of having power decrease is always greater than the probability of having power increase. If N equals 2, for instance, then the probability of power increase is equal to 1/2N=1/4=0.25 that is still less than 0.5.

• If the TPC commands from all the radio link sets are reliably “+1” then the output of γ is equal to “+1”.

• If a TPC command from any of the radio link sets is reliably “0” then the output of γ is equal to “–1”.

6.4.3.3.Algorithm 2 for processing TPC commands

With the second algorithm, “algorithm2”, the inner loop speed is decreased to 300Hz. This algorithm increases the reliability of the TPC commands and enables the emulation of adjustment step sizes smaller than 1.0 dB in e.g. static radio conditions. Additionally, it allows turning off the power control by transmitting an alternating series of TPC commands. The disadvantage of this algorithm is that due to the slower inner loop speed, the tracking of fast fading channel can be affected.




Page 77 of 77

6.4.3.3.1. TPC command received for UE not in soft/softer handover

When a UE is not in soft handover, only one TPC command is received in each slot. In this case, the UE processes the received TPC commands on a 5-slot cycle, where the sets of 5 slots are aligned to the frame boundaries without any overlap between each set of 5 slots. Under such conditions, the inner loop power control runs at a rate of 300 Hz. The value of TPC_cmd is derived as follows:

• For the first 4 slots of a set, TPC_cmd = 0 regardless of the value of the TPC command received in each of these slots.

• For the fifth slot of a set, the UE uses hard decisions on each of the 5 received TPC commands as follows:

If all 5 hard decisions in the set are 1 then TPC_cmd = “+1” in the 5th slot If all 5 hard decisions in the set are 0 then TPC_cmd = “-1” in the 5th slot Otherwise TPC_cmd = “0” in the 5th slot

6.4.3.3.2. TPC command received from links in softer handover

The same procedure as the one used for algorithm1 is applied in the case the TPC commands are received from links in soft handover and a combined TPC_cmdsofter is generated.

6.4.3.3.3. TPC command received from links in soft handover

To combine the TPC commands from radio links of different radio link sets, the UE first makes a hard decision on the value of each TPCi , where this parameter is defined as in 6.4.3.2.3. The UE then follows this procedure for 5 consecutive slots, resulting in N hard decisions for each of the 5 slots. During this step, the UE assumes that:

• The sets of 5 slots are aligned on the frame boundaries and there is no overlap between them.

• The value of TPC_cmd is zero for the first 4 slots. Finally, after the 5th slots, the UE determines the value of TPC_cmd for the 5th slot according to Equation 26.




Page 78 of 78

A temporary TPC command, TPC_tempi, is determined for each of the N sets of 5 TPC commands as follows

If all 5 hard decisions within a set are "1" then TPC_tempi = +1 If all 5 hard decisions within a set are "0" then TPC_tempi = -1 Otherwise TPC_tempi = 0

A combined TPC_cmd(5th slot) is calculated for the 5th slot following:

If 5.0_1

1

>∑=

N

iitempTPC

N TPC_cmd(5th slot) is set to 1

If any of the TPC_tempi equal -1 TPC_cmd(5th slot) is set to -1Otherwise TPC_cmd(5th slot) is set to 0

Equation 26: TPC_cmd calculation when in soft handover


The parameter describing the algorithm type is powerControlAlgorithm. It is recommended to use the “algorithm 1”. The basic information is provided in Table 39. Parent Object Parameter name Attribute Syntax &

Range Default Value Access

ULDPCHInfo powerControlAlgorithm Enumerated (pCALGORITHM-1, pCALGORITHM-2)

pCALGORITHM-1 RNC-CLI RW-EL

Table 39: Uplink inner loop power control algorithm related parameter.

6.4.4. Uplink Inner Loop Power Control Execution

6.4.4.1.Principle

Upon derivation of a single TPC_cmd, the UE adjusts the transmit power of the uplink DPCH(s) according to: If TPC_cmd equals 1 then the transmit power of the uplink DPCCH and DPDCHs

shall be increased by ∆TPC dB. If TPC_cmd equals -1 then the transmit power of the uplink DPCCH and DPDCHs

shall be decreased by ∆TPC dB If TPC_cmd equals 0 then the transmit powers remain unchanged




Page 79 of 79

6.4.4.2.Transmit Power Step Size

The S-RNC sends to the UE the transmitter adjustment step size ∆TPC via RRC signalling.. The 3GPP standard specifies that the UE transmitter shall support TPC commands adjustments steps ∆TPC of 1dB, 2dB and 3dB. As the supported step size is UE specific more information on this parameter and its accuracy should be searched in the 3GPP specification ([4]).

6.4.4.3.Transmit power limits – Maximum transmit power

Because the performances of CDMA-based networks are limited by interference, it is very important that each UE never transmits with a power above a maximum allowed value. This value is set by the “Maximum allowed uplink Tx power" transmitted from the S-RNC to the UE via RRC signalling as described in [7]. In the case several radio links are involved in a connection, e.g. when in soft/softer handover, the maximum transmit power for the UE should be calculated at the S-RNC as follows: Max_UL_Tx_Power = min(Max_UL_Tx_Power1, .. Max_UL_Tx_PowerN) Where N is the number of radio links involved in the call. This limit is calculated at call-setup, at addition of a new link or at deletion of an existing one. Upon reception of the relevant RRC message, the UE keeps its uplink transmit power below the indicated power value. If the new calculated uplink transmitted power is above an indicated maximum power value, the UE is expected to adjust the power to a level below the limit.

6.4.4.4.Transmit power limits – Minimum transmit power

The minimum transmit power cannot be set by the radio network and is specified in [4]. The minimum output power is defined as an averaged power in a time slot measured with a filter that has a Root-Raised Cosine filter response with a roll off α = 0.22 and a bandwidth equal to the chip rate. The minimum output power shall be less than –50dBm.


Parameter tPCStepSizeUL defines the uplink power control step size. Its recommended value is equal to step size of 1 dB. The maximum allowed uplink transmit power in the UE is specified by parameter MaxULDPCHPower. As a default setting, it is suggested to set the value to the maximum power level achievable by the UE. This should ensure maximum uplink coverage. A tuning of this value can be performed in the case of issues with uplink interference. The maximum power value is defined via the UE Power Classes as described in Table 40. More information for these parameters is included in Table 41. Current default setting (i.e. 33dBm) ensures that the uplink power is limited by the UE H/W capability thus no adjustment is required depending on the type of UE. Currently available UEs belong to Power Class 3 or 4.




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Power Class Nominal maximum output power Tolerance 1 +33dBm +1/-3 dB 2 +27dBm +1/-3 dB 3 +24dBm +1/-3 dB 4 +21dBm ± 2 dB

Table 40: UE Power Classes.

Parent Object Parameter name Attribute Syntax

& Range UEGTFCS

Instance Default Value

Access

All 0 tPCStepSizeUL Integer 0 (1.0dB), 1 (2.0dB) 50, 54 1 ULDPCHInfo

maxULDPCHPower Integer - dBm -50, ..,+33

All 33dBm RNC-CLI RW-EL

Table 41: Uplink power control step size and UE transmit power limit parameters.

6.4.5. Uplink DPCCH/DPDCH power gains

6.4.5.1.Effect of bit rate variability on uplink power control

On the uplink the DPDCH spreading factor and the amount of puncturing/repetition is a function of the amount of data to be transmitted over a radio frame. Therefore if the DPDCH power level is kept constant, signal energy per symbol will vary with the instant data rate. Considering as an example the service combination “uplink 64kbps + signalling” as defined in [12]. Table 42 gives the DPDCH Energy per Symbol, assuming the UE transmit power level is kept constant. The ratio of energy per symbol is calculated using (27).

⋅

⋅=

∑∑

iii

iii

NRM

NRMR

TFC referencefor

TFC consideredfor log10 (27)

Where The reference TFC is TFCI number 9 Ni is the number of channel coded bit on DCHi RMi is the associated rate matching value (i.e. 140 for signalling, 160 for 64kbps) At the same time, the uplink DPCCH is used by the uplink inner loop as reference sequence on which the SIRtarget has to be achieved. Given the results in Table 42, if the SIRtarget remains constant and if the power ratio between the uplink DPDCH and DPCCH were to be constant, the SIR on the DPDCH (hence the QoS) would be a function of the radio frame TFCI value, which is not acceptable.




Page 81 of 81

TFCI TFC

64kbps bearer

TFC signalling bearer

Number of bits / radio frame for 64kbps

Number of bits / radio frame for signalling

SF DPDCH Energy per symbol

0 TF0 TF0 0 0 No Tx No Tx 1 TF1 TF0 534 0 64 X + 6.3 dB 2 TF2 TF0 1062 0 32 X + 3.3 dB 3 TF3 TF0 1590 0 16 X + 1.5 dB 4 TF4 TF0 2118 0 16 X + 0.3 dB 5 TF0 TF1 0 129 256 X + 11.9 dB 6 TF1 TF1 534 129 32 X + 5.2 dB 7 TF2 TF1 1062 129 16 X + 2.7 dB 8 TF3 TF1 1590 129 16 X + 1.2 dB 9 TF4 TF1 2118 129 16 X

Table 42: DPCH energy per symbol figure per "uplink 64kbps+signalling"

In order to make the quality of service provided to a DPCH independent of the instant data rate, the concept of power gain between the uplink DPDCH and DPCCH has been introduced, allowing compensation for the fluctuations of processing gain inherent to rate fluctuations. The mechanism is based on the fact that the uplink DPCCH and DPDCH(s) are transmitted on different codes as illustrated in the Figure 23.

I

j

cd,1 βd

Sdpch,n

I+jQ

DPDCH

cc βc

DPCCH

S

jQ

Figure 23: Uplink DPDCH and DPCCH transmission.

After channelization, the real-valued spread signals are weighted by power gain factors βc for the DPCCH and βd for all DPDCHs. At every instant in time, at least one of the values βc and βd has the amplitude of 1.0. The β-values are quantized into 4 bit words as described in Table 43.




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Signalling values for

βc and βd Quantized amplitude ratios

βc and βd 15 1.0 14 14/15 13 13/15 12 12/15 11 11/15 10 10/15 9 9/15 8 8/15 7 7/15 6 6/15 5 5/15 4 4/15 3 3/15 2 2/15 1 1/15 0 Switch off

Table 43:Quantization of the gain factors.

6.4.5.2.Gain factors controlling procedures 6.4.5.2.1. Principle

In order to compensate for the DPDCH processing gain fluctuations, there is a set of βc and βd values defined per combination of the TFCS. They are transmitted by the RNC to the UE via RRC signalling and to the NodeB via NBAP messages. Beside of the gain factor values to be signaled in explicitly signalling case or to be taken as reference values in computing case, a Reference TFC ID is included in order to calculate the gain factors for the specific TFC. There are two ways of controlling the gain factors of the DPCCH code and the DPDCH codes for different TFCs in normal (non-compressed) frames:

• βc and βd are signaled for the TFC, or • βc and βd are computed for the TFC, based on the signaled settings for a

reference TFC. Several reference TFCs may be signaled. To be noticed that the update of the relative gain factors between DPDCH and DPCCH occurs at a rate of once per radio frame and it is independent from the uplink inner loop power control that updates every timeslot the DPCCH absolute power level with steps of ±∆TPC dB.

6.4.5.2.2. Signalling the gain factors

When the gain factors βc and βd are signaled for a certain TFC, the signaled values are used directly for weighting of DPCCH and DPDCH(s). The gain factor values shall be




Page 83 of 83

populated with the values extracted from the OAM MIB table corresponding to the radio bearer combination mapped onto the uplink DPDCH.

6.4.5.2.3. Computing the gain factors

Instead of being explicitly signaled, the gain factors βc and βd may be computed for certain TFCs, based on the signaled settings for a reference TFC. An overview of this method is provided as information in the next paragraphs. First, the computed method introduces following variables:

• βc,ref and βd,ref denote the signaled gain factors for the reference TFC • βc,j and βd,j denote the gain factors used for the j:th TFC • Lref denote the number of DPDCHs used for the reference TFC • L,j denote the number of DPDCHs used for the j:th TFC.

Then it defines the variable Kref and Kj as defined in (28) and (29) and a nominal power relation Aj computed as in (30).

∑ ⋅=i

iiref NRMK

(28)

where: • RMi is the semi-static rate matching attribute for transport channel i, • Ni is the number of bits output from the radio frame segmentation block for

transport channel i • the sum is taken over all the transport channels i in the reference TFC

∑ ⋅=i

iij NRMK

(29)

where the sum is taken over all the transport channels i in the j:th TFC.

ref

j

j

ref

refc

refdj K

KLL

A ⋅=,

,

ββ

(30)

The gain factors for the j:th TFC are then computed as follows:




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If Aj > 1 then βd,j=1. and βc,jis the largest quantized-value, for which the condition βc,j ≤ 1/Aj holds1

If Aj ≤ 1 then βd,jis the smallest quantized-value, for which the condition βd,j≥ Aj holds and βc,j = 1.0

The RNC shall support the RRC signalling of βc and βd values based on the “signaled gain factors” method. In the case where the gain factors of all the combinations are not explicitly given, at least one of the given values shall be used as a reference to derive the gain factor of the other combinations according to the “computed gain factors” method.

6.4.5.3.Translations settings

The gain factors signalling method, the gain factors βc and βd are defined respectively by the parameter gainFactorType, gainFactorBc and gainFactorBd. Information on the gain factors related parameters is available in Table 44: The prescribed method for the signalling of beta gain factor, in case of the computing method, is the following:

• explicitly declare the gain factor corresponding to the highest data rate of the TFCS through the parameter referenceTFC and use this TFC as the reference

• declare the other factor as computed using the above reference. Due to the limitation of the UE2 not supporting the computed method, the recommended value for gainFactorType is “sIGNALLED”. With the latest UE versions3, supporting the computed method, the parameter gainFactorType could also take the value “cOMPUTED”. Both parameters gainFactorBc and gainFactorBd can be defined with different values depending on the selected service combination specified through different instances of parent object UEGTFC. These parameter should ensure an optimal trade-off between low BLER on both DPDCH and DPCCH and uplink power consumption. As major performance issues were observed in soft/softer handover scenarios (due to downlink outer loop power control not working, power imbalance, and soft/softer handover delay) retune of gain factors has helped to mitigate the downlink DCH power imbalance. This was achieved by increasing the gainFactorBc with respect to gainFactorBd, i.e. from 8 and 15 to respectively 12 and 15. TPC detection success rate has improved without causing higher uplink power consumption.

1 Since βc,j may not be set to zero, if the above rounding results would equal zero, βc,j shall be set to the lowest quantized amplitude ratio of 1/15 as specified in Table 43. 2 This concerns mainly the Qualcomm TM5200, FM6208 3 This is for instance the case of the Qualcomm TM6200, WZ4220




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Parent Object


Service Combination

Default Value Access

gainFactorBc Integer - 0…15 gainFactorBd Integer - 0…15 referenceTFC Integer UEGTFC

gainFactorType Enumerated (sIGNALLED, cOMPUTED)

See default values in load RNC-CLI RW-EL

Table 44: Gain factors related parameters

In the case the UE supports it, the “computed gain factors” method can be used and the gain factor set according to Table 45. Note that due to the high number of parameters to be tuned and their impact on the system performances, it is highly not recommended to modify the beta values. The default values provided in the loads should be kept and only modified after testing in the Swindon Lab and verification in test environment.

Service profile βc βd Number of reference TFC (as per SRD-UTRAN-RCC-1)

DCCH signalling alone 15 8 1 [i.e. (TF1)] 64 kbps PS data+DCCH signalling 8 15 9 [i.e. (TF4)(TF1)] Voice+DCCH signalling 11 15 5 [i.e. (TF2)(TF1)(TF1)(TF1)] Voice+64kbps PS data+DCCH signalling 5 15 29 [i.e. (TF2)(TF1)(TF1)(TF4)(TF1)] 64 kbps CS Data+DCCH signalling 8 15 3 [i.e. (TF1)(TF1)]

Table 45: Default gain factors

Table 46: Gain factor tunings

For reference TFC: UEGTFC:gainFactorType set to signalled UEGTFC:isReferenceTFC set to true UEGTFC:ReferenceTFC and TFCNumber set to 0 UEGTFC:Bc and Bd set as per table Table 45 (depends on service combination) For other TFCs: UEGTFC:gainFactorType set to computed UEGTFC:isReferenceTFC set to false UEGTFC:ReferenceTFC and TFCNumber set to 0 UEGTFC:Bc and Bd set to any value




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6.4.6. Impact of Compressed Mode on uplink transmit power control

Uplink power control remains essentially the same as in the normal case, using the same UTRAN supplied parameters for Power Control Algorithm and step size (∆TPC), but with additional mechanism designed to help the recovery of the interrupted control loop after each transmission gap. Due to the transmission gaps in compressed frames for both uplink DPDCH(s) and DPCCH, there may be missing TPC commands in the downlink. If no downlink TPC command is transmitted, the corresponding TPC_cmd derived by the UE is set to zero.

6.4.6.1.Impact at the UE 6.4.6.1.1. Impact of the change of number of pilot bits

Compressed and non-compressed frames in the uplink DPCCH may have a different number of pilot bits per slot due to change in slot format. A change in the transmit power of the uplink DPCCH is needed in order to compensate for the change in the total pilot energy. Therefore at the start of each slot the UE derives the value of a power offset ∆PILOT. If the number of pilot bits per slot in the uplink DPCCH is different from its value in the most recently transmitted slot, ∆PILOT [dB] is given in (31)

=∆

currPILOT

prevPILOTPILOT N

NLog,

,10*10 (31)

where

• NPILOT,prev is the number of pilot bits in the most recently transmitted slot • N PILOT,,curr is the number of pilot bits in the current slot.

Otherwise, including during transmission gaps in the downlink, ∆PILOT is set to zero.

6.4.6.1.2. Impact of compressed mode on the uplink power control step size

Unless otherwise specified, in every slot during compressed mode the UE is expected to adjust the transmit power of the uplink DPCCH with a step of ∆DPCCH [dB] which is given in (32).

PILOTcmdTPCTPCDPCCH ∆+∆=∆ _* (32)




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6.4.6.1.3. Initial transmit power after an Uplink transmit gap

At the start of the first slot after an uplink or downlink transmission gap the UE applies a change in the transmit power of the uplink DPCCH by an amount ∆DPCCH [dB], with respect to the uplink DPCCH power in the most recently transmitted uplink slot according to (33).

PILOTRESUMEDPCCH ∆+∆=∆ (33) The value of ∆RESUME [dB] is determined by the UE according to the Initial Transmit Power mode. The ITP is a UE specific parameter, which is signaled by the network with the other compressed mode parameters. The different modes are summarized in Table 47.

Initial Transmit Power mode Description 0

gapTPC cmdTPCRESUME _*δ=∆ 1 lastRESUME δ=∆

Table 47 - Initial Transmit Power modes during compressed mode

In the case of a transmission gap in the uplink, TPC_cmdgap is the value of TPC_cmd derived in the first slot of the uplink transmission gap, if a downlink TPC_command is transmitted in that slot. Otherwise TPC_cmdgap equals zero. δlast is the most recently computed value of δi, which is updated according to the following recursive relations, which is executed in all slots in which both the uplink DPCCH and a downlink TPC command are transmitted, and in the first slot of an uplink transmission gap if a downlink TPC command is transmitted in that slot.

scTPCiii kcmdTPC **_*96875.0*9375.0 1 ∆−= −δδ (34) Where:

• TPC_cmdi is the power control command derived by the UE in that slot. • ksc = 0 if additional scaling is applied in the current slot and the previous slot and

ksc =1otherwise. • δi-1 is the value of δi computed for the previous slot. The value of δi-1 is initialized

to 0 o when the uplink DPCCH is activated, o at the end of the first slot after each uplink transmission gap, o at the end of the first slot after each downlink transmission gap.

• The value of δi is set to zero at the end of the first slot after each uplink transmission gap.




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6.4.6.1.4. Recovery period on the UE side

After a transmission gap in either the uplink or the downlink, the period following resumption of simultaneous uplink and downlink DPCCH transmission is called a recovery period. RPL is the recovery period length and is expressed as a number of slots. RPL is equal to the minimum value out of the transmission gap length and 7 slots. If a transmission gap is scheduled to start before RPL slots have elapsed, then the recovery period ends at the start of the gap, and the value of RPL is reduced accordingly. During the recovery period, 2 modes are possible for the power control algorithm. The Recovery Period Power control mode (RPP) is signaled with the other compressed mode parameters. The different modes are summarized in Table 48.

Recovery Period power control mode

Description

0 Transmit power control is applied using the algorithm determined by the value of PCA, with step size ∆TPC

1 Transmit power control is applied using algorithm 1 with step size ∆RP-TPC during RPL slots after each transmission gap

Table 48 – Recovery Period Power Control modes during compressed mode

For RPP mode 0, the step size is not changed during the recovery period and ordinary transmit power control is applied, using the algorithm for processing TPC commands determined by the value of PCA. Default PCA is PCA-1. Mode 0 is the default RPP mode. For RPP mode 1, during RPL slots after each transmission gap, power control algorithm 1 is applied with a step size ∆RP-TPC. The change in uplink DPCCH transmit power (except for the first slot after the transmission gap) is given in (35).

PILOTcmdTPCTPCRPDPCCH ∆+−∆=∆ _* (35) ∆RP-TPC [dB] is called the recovery power control step size.

• If PCA has the value 1, ∆RP-TPC is equal to the minimum value of 3dB and 2 ∆TPC.

• If PCA has the value 2,∆RP-TPC is equal to 1dB.




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After the recovery period, ordinary transmit power control resumes using the algorithm specified by the value of PCA and with step size ∆TPC. If PCA has the value 2, the sets of slots over which the TPC commands are processed shall remain aligned to the frame boundaries in the compressed frame. Hence, for both RPP mode 0 and RPP mode 1, if the transmission gap or the recovery period results in any incomplete sets of TPC commands, TPC_cmd shall be zero for those sets of slots, which are incomplete.

6.4.6.2.Impact on the uplink SIR target

When compressed mode is active the target SIR becomes a function of the presence, in the current radio frame, of uplink compressed mode gap and of the number of pilots bits. When compressed mode is active, the Node B shall calculate the uplink SIR target SIRcm_target as defined in (36).

codingSIRcodingSIRSIRSIRSIR PILOTettettcm _2_1argarg_ ∆+∆+∆+= (36) Where

• SIRtarget is the uplink SIR target value sent by the RNC • ∆SIR1_coding and ∆SIR2_coding shall be computed using the uplink parameters

DeltaSIR1, DeltaSIR2, DeltaSIRafter1, DeltaSIRafter2 sent by the SRNC through NBAP/RANSAP signaling, according to (37) and (38).

• ∆SIR1_coding = DeltaSIR1 if the start of the first transmission

gap in the transmission gap pattern is within the current uplink frame.

• ∆SIR1_coding = DeltaSIRafter1 if the current frame just follows a frame containing the start of the first transmission gap in the transmission gap pattern.

• ∆SIR1_coding = 0 dB in all other cases

(37)

• ∆SIR2_coding = DeltaSIR2 if the start of the second

transmission gap in the transmission gap pattern is within the current uplink frame.

• ∆SIR2_coding = DeltaSIRafter2 if the current frame just follows a frame containing the start of the second transmission gap in the transmission gap pattern.

• ∆SIR2_coding = 0 dB in all other cases.

(38)

=∆

framecurrPILOT

NPILOTPILOT N

NLogSIR_,

,10*10 (39)




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∆SIRPILOT shall be calculated as defined in (39), where: • Npilot,N is the number of pilot bits per slot in a normal uplink frame without a

transmission gap. • Npilot,curr_frame is the number of pilot bits per slot in the current uplink frame.

In case several compressed mode patterns are used simultaneously, ∆SIR1_coding and ∆SIR2_coding offsets shall be computed for each compressed mode pattern and all ∆SIR1_coding and ∆SIR2_coding offsets shall be summed together.


The corresponding translation settings are described in Table 49.


UEGTFCS Instance

Default Value

Access


0


0


0 Transmission GapPattern


All

0

RNC-CLIRW


7. Power control for Uplink Common Channels The only uplink common channel supported in U03.03 is the Random Access Channel. The power control technique used on this channel is a mix of open loop and a crude version of inner loop power control based on preamble power ramp up technique. Since this topic belongs to procedures in the RACH channel it is described in details in the TAN Access Procedures [15].




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8. Power Overload Control As sector/carrier power utilization is approaching the upper limit of sector/carrier power, the demanded power on the downlink may exceed the rated power of the amplifier. In order to maintain the signal quality of the existing calls and to protect the amplifier from overheating and shutting down, the UTRAN act on existing calls, new calls and/or incoming handover. The overload control can be basically separated into following categories:

• Power Overshoot Control (downlink only): This is a fast process with a reaction time of the order of a radio frame. It is based on the estimation of the overall transmit power on a given sector/carrier. If the measured value is higher than the rated power of the amplifier, various quick actions can be taken in order to reduce the aggregate transmit power of the sector. These actions consist of procedures as gain clipping, Aggregate Overload Control (AOC) and Modified Aggregate Overload Control (MAOC).

• Amplifier protection (downlink only): These strategies are based on the measurement of the temperature of the power amplifier. If a given critical temperature is reached, the amplifier enters a cool-down state involving a given set of transmit power limiting actions, such as power overshoot and call admission control. The sector transmitter resumes to its normal behavior when it switches back to the normal state.

• Load control algorithms (uplink and downlink): This is a slow process consisting in three main different algorithms, i.e. Call Admission Control, Dynamic Bearer Control and Congestion Control that respectively deny access to new incoming calls, deny RAB establishment or take actions on the already connected users. On the downlink the load evaluation is based on the downlink aggregate transmitted power.

8.1. UPLINK OVERLOAD CONTROL

Different procedures are implemented to control the overload in uplink. For more information refer to the Translation Application Note dealing with the Load Control Algorithms [13] as well as to the Access Procedures [15].

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Customer UMTS RF TAN U03.03 Power Control