07 HandoverControl 2006 Partner

1 © NOKIA RANPAR Version 2.0 / 09.02.2006 / rlim

Course Content

• Radio Resource Management Overview

• Parameter Configuration

• Common Channels & Power Control

• Load Control

• Admission Control

• Packet Scheduling

• Handover Control

• Resource Manager


Course Objectives

At the end of the course you will be able to:

• Name and describe the different Handover types

• Describe and list the steps of the Handover procedure for each Handover type

• Name and describe the main RAN parameters related to Handover reporting triggering

• Describe the main difference between inter system Handover and other Handover types

• Name and describe the main RAN parameters related to inter system Handover


Handover Control• Handover Types• Intra-Frequency Handover:

• Parameters Mapping• SHO Events and Measurements• Hard Handover & RRC Connection Release

• Traffic Balancing• Compressed-Mode• Inter-Frequency & Inter-System Handover:

• Measurement triggering• Measurements• HO decisions

• GSM ISHO• Load Based Handover to WCDMA• Emergency Inter-System Handover to GSM• Forced AMR voice call handover to GSM• Cell Reselection

• SRNS Relocation• IMSI Based Handover


• Intra-Frequency Handovers• Softer Handover

• Handover between sectors of the same Node B (handled by BTS)• No extra transmissions across Iub interface• Maximum Ratio Combining (MRC) is occurring in both the UL and DL

• Soft Handover• MS simultaneously connected to multiple cells (from different Node Bs)• Extra transmission across Iub, more channel cards are needed (compared to non-SHO)• Mobile Evaluated Handover (MEHO)• DL/UE: MRC & UL/RNC: Frame selection combining

• Hard Handover• Arises when inter-RNC SHO is not possible (Iur not supported or Iur congestion)• Decision procedure is the same as SHO (MEHO and RNC controlled)• Causes temporary disconnection of the (RT) user

• Inter-Frequency Handover• Can be intra-BS, intra-RNC, inter-RNC • Network Evaluated Handover (NEHO)• Decision algorithm located in RNC

• Inter-RAT Handover• Handovers between GSM and WCDMA (NEHO)

Handover Types




• Traffic Balancing • Compressed-Mode• Inter-Frequency & Inter-System Handover:

• Measurement triggering• Inter-Frequency & Inter-System Measurements• Inter-Frequency HO decision• Inter-System HO decision




HC Parameter Database Structure

• RNC = Radio Network Controller level parameters

• WBTS = Node B level parameters

• WCELL = Cell level parameters

• FMCx = Frequency Measurement Control parameters (S=intra-frequency set; I=inter-frequency; G=inter-RAT)

• ADJx = Adjacent Cell parameters (S=intra-frequency set; I=inter-frequency; G=inter-RAT)

• HOPx = Handover Path parameters (S=intra- frequency set; I=inter-frequency; G=inter-RAT)

S:Intra-FrequencyS:Intra-

Frequency

I:Inter-FrequencyI:Inter-

Frequency

G:Inter-System

G:Inter-System

WCELL

ADJG

ADJI

ADJS

WBTS

RNC

FMCS

FMCI

FMCG

100

100

100

HOPS 100

HOPI 100

HOPG 100

32

48

32


SHO: Neighbour Cell Definition

ADJS

ADJS

ADJS

FMCS(NRT)

FMCS(RT)

HOPS(RT)

HOPS(NRT)

HOPS(NRT)

HOPS(NRT)

HOPS(RT)

HOPS(RT)

HOPSid = 5

HOPSid = 10

FMCSid = 3

FMCSid = 40

ADJSid = 1

ADJSid = 2

ADJSid = 3

WCELWCELWCEL

WCEL

WCELWCELWCELWBTS

NrtFmcsIdentifier = 3

RtFmcsIdentifier = 40

NrtHopsIdentifier = 5RtHopsIdentifier = 10

Each WCEL has associated 1 FMCS for NRT & 1 for RT, both can be reused for other cells. Different FMCS’scould be defined for the different type of cells (urban, rural, macro/micro/pico)

Each ADJS has associated 1 HOPS for NRT & 1 for RT, both can be reused for other cells. Different HOPS’sparameters could be defined for the different type of cells (urban, rural, macro/micro/pico)


ADJS, HOPS & FMCSHO Parameter Categories

Intra-Frequency

Inter-Frequency

Inter-System

Handover Control ParametersRNC parametersWCEL parametersHOPS parameters FMCS parametersADJS parameters HOPI parameters FMCI parametersADJI parameters HOPG parameters FMCG parameters ADJG parameters

100HOPS parametersCell Re-selection HCS PriorityCell Re-selection HCS ThresholdCell Re-selection Minimum QualityCell Re-selection Minimum RX LevelCell Re-selection Penalty TimeCell Re-selection Quality Offset 1Cell Re-selection Quality Offset 2Cell Re-selection Temporary Offset 1Cell Re-selection Temporary Offset 2CPICH Ec/No Averaging WindowEnable Inter-RNC Soft HandoverEnable RRC Connection ReleaseHHO Margin for Average Ec/NoHHO Margin for Peak Ec/NoRelease Margin for Average Ec/NoRelease Margin for Peak Ec/No

Define Target Cell Selection

1100

FMCS parametersActive Set Weighting CoefficientAddition Reporting IntervalAddition TimeAddition WindowCPICH Ec/No Filter CoefficientCPICH Ec/No HHO CancellationCPICH Ec/No HHO Cancellation TimeCPICH Ec/No HHO ThresholdCPICH Ec/No HHO Time HysteresisCPICH RSCP HHO CancellationCPICH RSCP HHO Cancellation TimeCPICH RSCP HHO Filter CoefficientCPICH RSCP HHO ThresholdCPICH RSCP HHO Time HysteresisDrop TimeDrop WindowMaximum Active Set SizeReplacement Reporting IntervalReplacement TimeReplacement Window

Define Adjacent Cell Measurement Control

1

In GSM: Define HO TriggerHoThresholdsLevDL Rx (LDR): -92 dBm Px (LDP): 3 Nx (LDN): 4

Define Target Cell SelectionRx Lev Min Cell: -95 dBm

Define Adj Cell

31ADJS parameters Cell Identifier CPICH Ec/No Offset Disable Effect on Reporting Range Location Area Code Maximum UE TX Power on RACH Mobile Country Code Mobile Network Code Mobile Network Code LenPrimary CPICH power NRT HOPS Identifier Primary Scrambling Code RNC Identifier Routing Area Code RT HOPS Identifier Tx Diversity Indicator

Define Adj Cell

1


• Separate Handover Parameter Set (HOPS) identifiers for real time(RT) & non-real time(NRT) traffic

• RtHopsIdentifier - real time

• NrtHopsIdentifier - non-real time

• Each HOPS object is identified by a unique HOPSid (HOPS) in the RNC - on to which the RtHopsIdentifier and/or NrtHopsIdentifier parameters are mapped to identify the appropriate HOPS parameter set for that particular neighbor cell

• Primary scrambling code for neighbor cell specified using AdjsScrCode

• AdjsTxDiv specifies whether the neighbor cell is using Tx diversity

• AdjsTxPwrRACH determines the maximum power the UE can use on the PRACH when accessing the neighbor cell

Neighbour Cell Definition


SHO: Neighbour Cell Definition• Each intra-frequency neighbor (ADJS) is identified using ADJSid (ADJS)

• The ADJS parameters provide information on the identity of each neighbor cell together with its properties (i.e. Handover parameter set identifier, scrambling code etc..)

• Each neighbor cell is defined using the UTRAN cell identifier which comprises

UTRAN Cell Identifier = MCC + MNC + RNC identifier + Cell identifierUTRAN Cell Identifier = MCC + MNC + RNC identifier + Cell identifier

• Each neighbor cell is defined using the UTRAN cell identifier which comprises;

MCC (Mobile Country Code) = AdjsMCCMNC (Mobile Network Code) = AdjsMNCRNC Identifier = AdjsRNCidCell Identifier = AdjsCI

• The LAC (AdjsLAC) & RAC (AdjsRAC) are also in ADJS parameter set

ADJS Parameters


SHO: Neighbour Cell Definition

AdjsMCCAdjsMNCAdjsRNCidAdjsCI

UTRAN Cell ID

ADJSid

MaxActiveSetSizeRNCAdjsScrCodeAdjsTxDivAdjsTxPwrRACH

• RT HO Control Parameter: RtHopsIdentifier• NRT HO Control Parameter: NrtHopsIdentifier









Soft Handover

• HC supports the following measurement reporting events:• Event 1A: A primary CPICH enters the reporting range (Ncell addition)

• Event 1B: A primary CPICH leaves the reporting range (Ncell deletion)

• Event 1C: A non-active CPICH becomes better than an active primary CPICH (Ncellreplacement)

• Cell individual offsets for modifying measurement reporting behaviour

• Mechanism for forbidding a neighbor ing cell to affect the reporting range

• Handover decision performed by RNC based on measurements and available resources

• Admission Control can reject the branch addition in case the maximum load is achieved in DL (threshold + offset), valid both for RT and NRT bitrates.

• Hard blocking may prevent branch addition


• The Handover measurement is based on CPICH Ec/Io

• The accuracy of pilot Ec/Io measurements is important for Handover performance

• Measurement accuracy depends on the filtering length and mobile speed.• When a MS moves slowly or is stationary, filtering length (in ms) has to be just long enough to

avoid fast fades leading to errors and causing unnecessary Handovers within a short period.• Long filtering length will cause Handover delays to fast moving MS

• UE can perform averaging on EC/IO measurement prior to the event reporting process

• EcNoFilterCoefficient (FMCS) defines the measurement period for intra-frequency CPICH EC/IO measurements used by UE (default = 600ms). In the CELL_DCH state the UE physical layer measurement period for intra frequency CPICH Ec/No measurements is 200 ms. The Filter Coefficient parameter controls the higher layer filtering of physical layer CPICH Ec/No measurements before the event evaluation and measurement reporting is performed by the UE.

• RNC averages CPICH Ec/Io measurements using EcNoAveragingWindow (HOPS) - defines the number of event triggered periodic intra-frequency measurement reports used by RNC to calculate averaged CPICH EC/IO (default = 8 Measurements)

SHO: Measurement Control

Wei Yun

Note

if UE measurement period is 200ms, means that within the 600ms of EcNoFilterCoefficient, 3 measurement will be taken for averaging, after that, event will be triggered, for example e1a, then will wait for addition time of 100ms to confirm if condition still meet then will add cell into AS. Question: the 100ms of addition time is less than one measurement period (200ms), so is it means that UE will take reference the last measurement result during addition time to check if condition still meet, as setting the addition time within 0-199ms seems no difference?


SHO: Measurement Control

Node B

UTRAN

RNCUE

Measurement Control [ ]

I am in the CELL_DCH sub-state

Measurement Type: Intra-frequency measurements• Reporting events:

1A: A primary CPICH enters the reporting range 1B: A primary CPICH leaves the reporting range 1C: A non-active CPICH becomes better than an active primary CPICH

• Event triggered / Periodical reporting • Measurement quantity: CPICH Ec/No• etc.

System Information [ ]

SIB 11/12• EcNoFilterCoefficient

Measurement accuracy depends on• speed &• Filter Coefficient

EcNoAveragingWindow


1A: A Primary CPICH Enters the Reporting Range• Reporting range defined by offset (point 1 on next slide) from either

(i) best CPICH Ec/Io in the AS, or(ii) sum of the AS measurement resultsset using ActiveSetWeightingCoefficient (FMCS) (0 = use best CPICH : <>0 = use sum)

• Offset defined using AdditionWindow (FMCS)

• Event 1A triggered when CPICH3 Ec/Io enters UE reporting range (point 2)

• If CPICH3 Ec/Io remains within reporting range for a time period defined by AdditionTime (FMCS) , and the AS is not full, UE sends measurement report to RNC which adds Ncell3 to AS if possible (point 3)

• AdditionTime defines the 'time-to-trigger' interval between the Ncell first entering the reporting range and the UE sending the measurement report to the RNC

• If RNC is unable to add Ncell to AS, UE will wait for a period of time, defined by AdditionReportingInterval (FMCS) (point 4) after the first measurement report, before sending further reports periodically, with interval AdditionReportingInterval, until (a) Ncell moves out of reporting range, or (b) RNC adds Ncell to AS.


4

Strongest CPICH in AS

1A: A Primary CPICH Enters the Reporting Range

time

Ec/Io

P CPICH 3

P CPICH 1

P CPICH 2

1

2

3

AdditionWindow

AdditionTime

AdditionReportingInterval

RNC

MeasurementReport

Add tothe AS?

no

ActiveSetWeightingCoefficient


• Reporting criteria of event 1A in 25.331/RRC Measurement Control :

• Reporting Cell Status: All active cells + 2 monitored cells.

• Triggering Condition: Monitored Set cells

• Reporting Range Constant AdditionWindow / 4 dB

• Cells forbidden to affect Reporting range: AdjsDERR / Enable

• W: ActiveSetWeightingCoefficient / 0

• Time to trigger: AdditionTime / 0 = 0 ms

• Reporting deactivation threshold: MaxActiveSetSize = 3

• Amount of reporting: infinity

• Reporting interval: AdditionReportingInterval / O.5 s





1B: A Primary CPICH Leaves the Reporting Range

• Event 1B triggered when CPICH3 EC/I0 drops out of the UE reporting range for a defined period of time (point 1 on next slide)

• Reporting range = Strongest CPICH in AS - DropWindow (FMCS) (point 2)

• Time-to-trigger period set using DropTime (FMCS) (point 3)

• UE sends RNC measurement report on expiry of DropTime to remove Ncell (CPICH3) from AS.

• RNC drops the cell from the AS and UE drops the cell from the AS to the Neighbour Set


Strongest CPICH in AS

time

Ec/Io

P CPICH 3

P CPICH 1

P CPICH 2

1

2

3

DropWindow

DropTime

MeasurementReport

1B: A Primary CPICH leaves the Reporting Range

Remove the reported cell from the AS


• Reporting criteria of event 1B in 25.331/RRC Measurement Control :

• Reporting cell Status: 3 active cells

• Triggering Condition: Active cells

• Reporting Range Constant: DropWindow / 4 dB

• Cells forbidden to affect Reporting range AdjsDERR / Enable

• W : ActiveSetWeightingCoefficient / 0

• Time to trigger: DropTime / 320 ms





Soft and Softer Handover (case1)

reportCriteria intraFreqReportingCriteria : {eventCriteriaList {{event e1a : {

triggeringCondition monitoredSetCellsOnly,reportingRange 4,w 0,reportDeactivationThreshold t2,reportingAmount ra-Infinity,reportingInterval ri0-5},hysteresis 0,timeToTrigger ttt100,reportingCellStatus allActiveplusMonitoredSet :

viactCellsPlus2}

event e1b : {triggeringCondition activeSetCellsOnly,reportingRange 6,w 0},hysteresis 0,timeToTrigger ttt640,reportingCellStatus withinActiveSet : e3},

• SIB 11 contains the relevant parameters to read when in idle mode

• These are valid in connected mode prior to receiving the measurement control that overwrites them

• In this example:• Addition window= 2 dB (factor of 2

mapping between the signalled value and the actual value, TS 25.331 defines this mapping)

• Addition time = 100 ms

• Reporting interval = 500 ms

• Drop window = 3 dB (factor of 2 mapping between the signalled value and the actual value)

• Drop time = 640 ms

Extract from SIB 11


SIB11 length limitation• 3GPP has inconsistent requirements concerning the maximum number of neighbouring

cells that can be broadcasted in the SIB 11 and 12• SIB 11 and 12 can contain information on the maximum of 96 cells (32 intra-

frequency cells, 32 inter-frequency cells and 32 GSM cells)• On the other hand, the physical size of SIB data (no more than 3552 bits) has capacity

only for 47 cells!!

• If too many adjacencies are declared, the cell will go blocked by system with alarm: 7771 WCDMA CELL OUT OF USE (BCCH scheduling error) in RAN04

• As a rule of thumb, assuming that …

ADJS=15, ADJG=15, ADJI=15

… and “realistic worst case values”, SIB11 length = 3187.5 < 3552 -> OK!!

• Some sites might need additional neighbors and might pose a problem with the SIB11 limitation

• Avoid setting AdjsQoffset2 values, different CPICH values or other parameters used to tune cell reselection or handover

Further information Technical Note No. 046 / Restriction on number of cells in SIB11/12 due to inconsistency problem in 3GPP TS 25.331


1C: A non-active CPICH becomes better than an active primary CPICH

• UE AS full (MaxActiveSetSize = 3)

• Event 1C triggered when CPICH4 EC/IO > CPICH3 in AS by a defined margin, ReplacementWindow (FMCS). (point 1 in next slide)

• Sending of measurement report to RNC can be delayed by using 'time-to-trigger' period set by ReplacementTime (FMCS)

• If 'time-to-trigger' is used difference between CPICH4 and CPICH3 must be ≥ReplacementWindow for the period of ReplacementTime (point 2)

• If the RNC is not able to replace the Ncells, the UE continues to send measurement reports periodically, with interval ReplacementReportingInterval, to the RNC until (a) CPICH4 falls out of ReplacementWindow or (b) RNC replaces CPICH4 by CPICH3 (point 3)


time

weakest CPICH3 in AS

Ec/Io

P CPICH 3

P CPICH 1P CPICH 2P CPICH 4

AS has 3 cells

ReplacementReportingInterval3

1

2

ReplacementWindow

ReplacementTime

MeasurementReport

RNC

ASupdate?

no



• Reporting criteria of event 1C in 25.331/RRC Measurement Control :

• Reporting cell Status: All active cells + 2 monitored cells.

• Hysteresis: ReplacementWindow / 2 dB

• Time to trigger: ReplacementTime / 0 = 0 ms

• Replacement activation threshold : MaxActiveSetSize / 3

• Amount of reporting: infinity

• Reporting interval: ReplacementReportingInterval / 0.5s





Soft and Softer Handover (case 2)

event e1c : {replacementActivationThreshold t3,reportingAmount ra-Infinity,reportingInterval ri0-5},hysteresis 4,timeToTrigger ttt100,reportingCellStatus withinActiveSet : e3}

• In this example:• Replacement window = 1 dB

• Replacement time = 100 ms

• Reporting interval = 500 ms

• Replacement window requires mapping to its true value according to:

4/(2*2) = 1 dB

• There are two mappings – first is the signalled value to actual value mapping and second is the way in which hysteresis is applied in the event triggering equation (TS25.331)

• Once in connected mode the networks sends the same set of information elements via a measurement control message

• Nokia’s implementation is that the values in the measurement control message are the same as those within SIB 11

• Events 6F and 6G are configured in a similar fashion i.e. within SIB 11 and subsequently

Extract from SIB 11 cont.

with a measurement control message


Individual Ncell Offset &Forbidding Neighbour Cell from Reporting Range

Individual Ncell Offset

• cell individual offsets for modifying measurement reporting behaviour

• effectively 'moves' cell border (shrinks or enlarges cell)

• offset set using AdjsEcNoOffset (= CPICH Ec/No Offset) (ADJS)

• offset applied to Primary CPICH measurements before event evaluation by the UE

Forbidding Neighbour Cells from Reporting Range

• the primary CPICH of certain cells can be forbidden from reporting range calculation in some instances

• cells can be forbidden from reporting range using AdjsDERR (ADJS)


Individual Ncell Offset

time

P CPICH 1

P CPICH 2

P CPICH 3

Reporting Range

Reporting Event 1B

Reporting Event 1A

AdjsEcNoOffset

Artificially EnlargingCell 3 by x dB

Ec/Io


Forbidding Neighbour Cell from Reporting Range

Time

P CPICH 1

P CPICH 2

P CPICH 3

PCPICH3 is forbidden to affect the reporting range as its quality is quite unstable.

Reporting Range

AdjsDERR

Ec/Io


Event 1A(Add)

Event 1B(Drop)

Event 1C(Replace)

Active set cells +2 monitored set

cells

Monitored set cells

Addition Window/4 dB

Active set cells Active set cellsDrop Window/

6 dB

Active set cells +2 monitored set

cells- Replacement

Window/4 dB

Addition Time/0 ms

AdditionReportingInterval/0.5 s

Drop time/320 ms -

Replacementtime/0 ms

ReplacementReportingInterval/

1s

Event Reporting cell status

Triggering Condition

Reporting Range/Hysteresis Time to Trigger Reporting

Interval

• 3GPP reporting events 1A, 1B and 1C (also 6F and 6G)• CPICH Ec/Io is used as a measurement quantity rather than CPICH RSCP

• CPICH Ec/Io measurements are more accurate• 1A and 1B reporting range is defined by strongest active set cell• 1C reporting range is defined by weakest active set cell

SHO Summary

Wei Yun

Note

max 5 cells


• SHO for synchronisation reason:• Event 6F: The UE Rx-Tx time difference for a Radio Link (RL) included in the active set

becomes larger than an absolute threshold Reporting• Reporting event 6G: The UE Rx-Tx time difference for a RL included in the active set

becomes smaller than an absolute threshold

• Estimation of these events:• Based on UE Rx-Tx time difference

• Measurement configuration:• Time-to-trigger: not used.• 6F: UE Rx-Tx time difference threshold: UpperRxTxTimeDiffdefault: 1174 chips, range:1152 ... 1280 chips, step 1 chip

• 6G: UE Rx-Tx time difference threshold: LowerRxTxTimeDiffdefault: 874 chips range: 768 ... 896 chips, step 1 chip

• NOTE: Some UE does not support these events

UE Internal Measurements


Node B

UTRAN

RNCUE

Measurement Control [ ] I am in the

CELL_DCH sub-state

Measurement Type: UE Internal measurements• Reporting events:

6F: The UE Rx-Tx time difference for a RL included in the active set becomes larger than an absolute threshold Reporting 6G: The UE Rx-Tx time difference for a RL included in the active set becomes smaller than an absolute threshold

DLnom

time

T0

UL DPCH

time

time

6F 6G

UE Internal Measurements

Question: what is the action after receiving MR e6f ?


• Measurement reporting criteria are cell specific

• Neighbouring cells (ADJS and HOPS parameters) are defined on a controlling cell (cell from which the call has been started or best cell in case the original cell has been deleted from the active set)

• During SHO the measurement reporting criteria are taken from the cell where the UE has started the connection

• The measurement reporting criteria are updated only when the Original (Reference) cellleaves the Active Set (Nokia Implementation), according to the strongest cell in the Active Set, by sending the MEASUREMENT CONTROL message, transmitted on the downlink DCCH. Standard would allow to update reporting criteria, according thecurrent best server.

• Note: When Reference cell (not always the best cell) leaves the Active Set, it could be easily identified since this is followed by UTRAN MOBILITY INFORMATION & UTRAN MOBILITY INFORMATION CONFIRM to indicate that AS Reference Cell has changed.

• When the UE receives a MEASUREMENT CONTROL message, the UE shall stop monitoring and measurement reporting and shall replace the measurement reporting criteria with the new information received in the MEASUREMENT CONTROL message.

Measurement Report Updating

Wei Yun

Note

how to identify the reference cell? is it the cell with ID=0 after the instance of UTRAN mobility info? No, not ID=0, the reference cell is the 1st cell within the list in measurement control message but not necessary ID=0


Measurements Reporting Criteria Updating during Soft Handover

Cell 1 Cell 2

•Neighbour ListCell1• Addition WindowCell1•Drop WindowCell1•Drop TimeCell1

1. Idle Mode

System Information

(BCCH)

BEST Server: Cell 1BEST Server: Cell 1

2. Connected Mode: Cell_DCH

The UE shall continue monitoring the list of neighboring cells assigned in System Information during Idle Mode

The UE shall continue monitoring the list of neighboring cells assigned in System Information during Idle Mode

Measurement Reporting Criteria according to Cell 1


The UE shall send the MEASUREMENT REPORT message when reporting

criteria are fulfilled.

The UE shall send the MEASUREMENT REPORT message when reporting

criteria are fulfilled.

Connected Mode: Cell_DCH

3. MEASUREMENT REPORT (DCCH)



Intra-frequency MeasurementIntra-frequency Measurement

The measurement reporting criteria are updated as soon as the original cell drops out from the Active Set (Nokia

Implementation).

The measurement reporting criteria are updated as soon as the original cell drops out from the Active Set (Nokia

Implementation).

Connected Mode: Cell_DCH

4. MEASUREMENT

CONTROL (DCCH)

•Neighbour ListCell2•Addition WindowCell2•Drop WindowCell2•Drop TimeCell2




Reporting Criteria

Updating


Neighbour List Measurement during SHO

Cell 1 Cell 2

Intra-frequency MeasurementIntra-frequency Measurement

•Addition WindowCell1•Drop WindowCell1•Drop TimeCell1

1. System Information (BCCH)


Neighbour List Cell 1Neighbour List Cell 1

Measurement Reporting Criteria according to

Cell 1


Cell 1

Active Set: Cell 1Active Set: Cell 1

2

3

5

2

3

5

3. MEASUREMENT REPORT (DCCH)

1A1B6. MEASUREMENT REPORT

(DCCH)

4. ACTIVE SET UPDATE

8. MEASUREMENT CONTROL (DCCH)

•Addition WindowCell2•Drop WindowCell2•Drop TimeCell2


Measurement Reporting Criteria according to Cell 2Measurement Reporting

Criteria according to Cell 2

Neighbour List Update

1

3

4

1

3

4

Neighbour List Cell 2Neighbour List Cell 2

Active Set: Cell 2Active Set: Cell 2Meas. Rep.

Criteria Update


Cell 1


Cell 1

3

1

4

2

5

3

1

4

2

5

Neighbour List CombinationNeighbour List Combination

Neighbour List Update

5. MEASUREMENT CONTROL (DCCH)

Active Set: Cell1 - Cell2Active Set: Cell1 - Cell2

2. Setup Call

2. Setup Call

7. ACTIVE SET UPDATE


• In Nokia RAN the measurement quantity for events 1A, B, C, E, F is P-CPICH Ec/No and for 1E,F also P-CPICH RSCP

• There are a huge number of intra-frequency measurement parameters.

• Please refer to the WCDMA Parameter Dictionary.

• See Measurement Control Parameter Set (FMCS object) which controls the intra-frequency measurements radio bearer, such as:

• 1A paramters:•ActiveSetWeightingCoefficient, AdditionReportingInterval, AdditionWindow, AdditionTime, MaxActiveSetSize, etc.

• 1B parameters:•ActiveSetWeightingCoefficient, DropTime, DropWindow, etc.

• 1C parameter:•MaxActiveSetSize, ReplacementReportingInterval, ReplacementTime, ReplacementWindow, etc.

• 1E parameter:•HHoEcNoCancel, HHoEcNoCancelTime, HHoRscpCancel, HHoRscpCancelTime, etc.

• 1F parameter:•HHoEcNoCancel, HHoEcNoTimeHysteresis, HHoRscpCancel, HHoRscpThreshold, HHoRscpTimeHysteresis, etc.

Nokia Parameters for Intra-Frequency Measurements


• In the RRC idle state and in the RRC connected sub-states CELL_FACH, CELL_PCH and URA_PCH, the UE is responsible for cell selection and re-selection.

• It camps on one cell or it is served by one cell. • By reading the System Information Block 11 and/or 12, the UE gets the

•Intra-frequency cell info list,•Inter-frequency cell info list, and•Inter-RAT cell info list,•i.e. it gets several neighbourhood lists.

• In the CELL_DCH sub-state, the RNC must be able to continuously update the neighbour cell lists in order to reflect the changing neighbourhood of a moving mobile station.

• This is part of the RNC‘s handover control. • If we have more than one active set cell, which participate in a soft handover, the handover control

of the RNC is responsible to combine the lists into one neighbour cell list which is then transmitted to the mobile station.

• The neighbour cell list combination is carried out in the steps depicted in next slide.• A soft handover only takes place with cells on the same UTRA carrier band. Consequently, the

combining of neighbourhood lists of several active set cells is only required for intra-frequency handovers and has to combined with their measurements.

Neighbour Lists


Cell 5 Cell 6 Cell 7 Cell 8



Neighbour List Cell 6:•Cell 2•Cell3•Cell 7

•Cell 11•Cell 10•Cell 5

Neighbour List Cell 7:•Cell 3•Cell4•Cell 8

•Cell 12•Cell 11•Cell 6

Cell 3Cell11

Cell 3Cell11

Neighbour cells which are common to Cell 6 and

Cell 7 Cell 4Cell 8

Cell 12Cell 6

Cell 4Cell 8

Cell 12Cell 6

Neighbour cells defined only for Cell 7

Cell 2Cell7

Cell 10Cell 5

Cell 2Cell7

Cell 10Cell 5

Neighbour cells defined only for Cell 6

Two Cells in the Active Set

Neighbourhood List Combination for Intra-frequency HOs


Cell 2Cell 5Cell 7Cell 9


Cell 41Cell 6

.....

Cell 43



Cell 41Cell 6

.....

Cell 43



Cell 10Cell 56

…...

Cell 25



Cell 10Cell 56

…...

Cell 25


Cell 11Cell 50Cell 9


…...

Cell 33




…...

Cell 33

Neighbour Cells Lists Step 1Step 1

Three Cells in the Active Set

Cell2Cell 7Cell 9

Cell2Cell 7Cell 9

Common to 3 Neighbour Lists

Step 2Step 2




…..…

Cell 22


…..…

Cell 22

Max 32 Cells

Neighbour Cells defined for only 1 Neighbourlist: best Ec/No first Step 4Step 4

Common to 2 Neighbour

Lists

Step 3Step 3



• The neighbourhood lists for intra-frequency handover measurements can be composed like this:• Step 1: Active set cells

•First the handover control sets the active set cells into the neighbour cell list.• Step 2: Neighbour cells which are common to three active set cells

•During the second step of neighbour cell list combination the handover control selects those neighbour cells which are common to all three active set cells. •If the total number of relevant neighbour cells exceeds the maximum number of 32 after the second step, the handover control removes in random order those surplus cells from the combined neighbour cell list which are selected during the second step

• Step 3: Neighbour cells which are common to two active set cells•During the third step of neighbour cell list combination the handover control selects those neighbour cells which are common to two active set cells. •If the total number of relevant neighbour cells exceeds the maximum number of 32 after the third step, the handover control removes in random order those surplus cells from the combined neighbour cell list which are selected during the third step.

• Step 4: Neighbour cells which are defined for only one active set cell•During the fourth step of neighbour cell list combination the handover control selects those neighbour cells which are defined for only one active set cell (random).•If the total number of relevant neighbour cells exceeds the maximum number of 32 after the fourth step, the handover control removes those surplus neighbours from the combined neighbour cell list which are selected during the fourth step, starting from the neighbours of the weakest (CPICH Ec/Io) active set cell.



Testing Details

06Mar29 adjs Ec_no offset update_in to outdoor--a lot round.rar


AdjsEcNoOffset Testing Candidate Sites / Cells

1-way AdjsEcNoOffset = 6dB:13016 (36) 26016 (382) Rest = 0dB offset

1-way AdjsEcNoOffset = 6dB:13016 (36) 26016 (382) Rest = 0dB offset

• Testing sequence / scenario:

• 1-way AdjsEcNoOffset = 6dB defined between 11036 (36) 26016 (382). Rest of the ADJS = 0dB offset.

• UE initiate call under 16016 (374) with AS: SC374 as Reference Cell. MC indicates that SC382 (intraFreqCellID = 12) is without any AdjsEcNoOffset = 6dB

• UE moves towards 11036 (36), with SHO in between.

• When Reference cell change occurs; i.e. SC374 leaves the AS, SC36 became the newAS Reference Cell. (signified by UE receiving UMI & UMIC after MR e1b to remove Reference Cell from AS)

• DL sends MC to indicate new set of intra-frequency reporting criteria (e1a, e1b etc) ; as well as modify UE NB list; i.e. removing old NBs unique to SC374 & add new common NBs. Also, modify FreqCellID=12, SC382 with AdjsEcNoOffset=6dB.

• Individual Cell Offset works!!

Wei Yun

Note

AdjsEcNoOffset between A->B, for example 6dB: means when reference cell change to A, then B is artificially seems to be 6dB better than its original value


AdjsEcNoOffset Verification• RRC connection setup

on 16016 (374). SC374 is the Active Set (AS) Reference Cell.



on 16016 (374).

• Measurement Control sent indicating AS Reference Cell neighbour list.

• Note: intraFreqCellID = 12 SC382 has NO AdjsEcNoOffset defined.



on 16016 (374).



• UE sends MR e1b to remove Reference Cell SC374 from AS.

• This is followed by UMI & UMIC to indicate that AS Reference Cell has changed (to SC36).


AdjsEcNoOffset Verification• RRC connection setup on

16016 (374).



• UE sends MR e1b to remove Reference Cell SC374 from AS.

• This is followed by UMI & UMIC to indicate that AS Reference Cell has changed (to SC36).

• DL sends MC (based on SC36) to indicate new set of intra-frequency reporting criteria (e1a, e1b etc). As well as modify UE NB list; i.e. removing old NBs unique to SC374 & add new common NBs.

• Note: Also, modify intraFreqCellID=12, SC382 with AdjsEcNoOffset=6dB (mapping IE x 2 12).

• Individual Cell Offset works!!


Conclusion


Conclusion of Parameter Verification:• Obviously the Individual Ncell individual offsets for modifying measurement reporting

behaviour works!! Else we would be in deep shit!! ;-)• However, based on the test scenario in this report, and Nokia Implementation**, it

should be noted that the Individual Cell Ec/No Offset definition or chaining between NCells would only come into effect IF the mutual cells became the AS Reference Cell with the old Reference Cell (who did not define AdjsEcNoOffset) removed.

• So, depending on the direction of drives, it may happen that in the case of some inconsistant drop calls along the highways or byways (with consistant deep fades due to physical structures obstruction etc) may still occur, although the individual cell EcNo offset was defined mutually between 1 pair of cells. Becos the AS Reference Cell was simply not changed in time to either of the supposedly chained pair of cells to modify the NB list to reflect the Ec/No Offset.

• For those serious and consistant drop call cases with the above symptom, on a case-by-case basis, it may be so that the possible solution is to define AdjsEcNoOffset to the earlier AS Reference Cell as well, which has NB definition both the supposedly chained pair of cells. (example to be included later, ZhongSan HW 6009U case)

• ** - The measurement reporting criteria are updated only when the original cell leaves the Active Set (Nokia Implementation), according to the strongest cell in the Active Set, by sending the MEASUREMENT CONTROL message, transmitted on the downlink DCCH. Standard would allow to update reporting criteria, according the current best server.









• If RNC is not able to add (Event 1A) to or replace (Event 1C) an Ncell from the AS, UE sends periodic measurement reports (AdditionReportingInterval /ReplacementReportingInterval) until;

• Ncell is added/replaced in to AS• Ncell leaves reporting range• HO no longer required (e.g. different Ncell enters AS)

• RNC may not be able to add/replace Ncell due to (a) Iur congestion or (b) inter-RNC SHO is prevented due to setting of EnableInterRNCsho (HOPS) (Point 1 in next slide)

• If CPICH EC/NO of non-active Ncell continues to increase it will cause additional interference due to a non-optimal connection (point 2)

Hard Handover


HHO decision

• To avoid excessive uplink interference, RNC will perform an intra-frequency hard Handover if either of the following criteria are met

AveEcNoDownlink + HHoMarginForAveEcNo(n) < AvEcNoNcell(n)

EcNoDownlink + HHoMarginPeakEcNo(n) < EcNoNcell(n)

• AveEcNoDownlink and AvEcNoNcell(n) = measured values for the best AS cell and the nth NS cell, averaged over EcNoAveragingWindow measurements

• EcNoDownlink and EcNoNcell(n) = instantaneous values

• HHoMarginForAveEcNo (HOPS) = average Ec/N0 margin [-6 … 6]dB, default 1dB

• HHOMarginPeakEcNo (HOPS) = peak Ec/N0 margin [-6 … 6]dB, default 2dB


Time

Ec/Io

P CPICH 3

P CPICH 1

P CPICH 2Reporting

range


1

2

HHOMarginAverageEcNoHHOMarginPeakEcNo

1A (AdditionTime = 0)

AveEcNoDownlink + HHOMarginAveEcNo < AveEcNoNcellEcNoDownlink + HHOMarginPeakEcNo < EcNONcell

Hard Handover

3


Inter-RNC intra-frequency Hard Handover(HHO)

• Intra-frequency hard handover is required to ensure handover between cells controlled by different RNCs when an inter-RNC Soft Handover is not possible

• No Iur between RNCs• Iur congestion or failure

• Intra-frequency hard Handover is lossless for NRT radio bearer but it causes short disconnection of RT radio bearer.

• Intra-frequency hard handover decisions made by the RNC are based on the intra-frequency measurement results, which are usually applied to the SHO procedure

• Also Enable Inter-RNC SHO parameter in intra-frequency HO path defines whether intra-frequency HO from the serving cell to a specified neighbour cells is performed as soft of hard

• Mobile evaluated Handover (MEHO)

CN

RNCRNC

Iu Iu

Iur

CN

RNCRNC

Iu Iu

Iur


Inter-RNC intra-frequency Hard Handover (HHO)

• If RNC is not able to add (Event 1A) to or replace (Event 1C) an Ncell from the AS, UE sends periodic measurement reports (AdditionReportingInterval/ ReplacementReportingInterval) until;

• Ncell is added/replaced in to AS• Ncell leaves reporting range• HO no longer required (e.g. different Ncell enters AS)

• RNC may not be able to add/replace Ncell due to (a) Iur congestion or (b) inter-RNC SHO is prevented due to setting of EnableInterRNCsho (HOPS) (point1 on next slide)

• If CPICH EC/NO of non-active Ncell continues to increase it will cause additional interference due to a non-optimal connection (point 2)

• To avoid excessive uplink interference, RNC will perform an intra-frequency hard handover to the Ncell (CPICH3) if either of the following criteria are met (point 3);

AveEcNoDownlink + HHOMarginAveEcNo < AveEcNoNcell

EcNoDownlink + HHOMarginPeakEcNo < EcNONcell

Parameters :

• Enable Inter-RNC Soft Handover ( YES/NO, default = YES )

• HHO margin for Peak EcNo (-6…6 dB, default =2 dB)

• HH Margin for Average EcNo (-6…6 dB, default=1 dB)


Time

Ec/Io

P CPICH 3

P CPICH 1

P CPICH 2Reporting

range


1

2

HHOMarginAverageEcNoHHOMarginPeakEcNo

1A (AdditionTime = 0)

AveEcNoDownlink + HHOMarginAveEcNo < AveEcNoNcellEcNoDownlink + HHOMarginPeakEcNo < EcNONcellAveEcNoDownlink + HHOMarginAveEcNo < AveEcNoNcellEcNoDownlink + HHOMarginPeakEcNo < EcNONcell

3

Inter-RNC intra-frequency Hard Handover (HHO)

Wei Yun

Note

for HHO, the active cell will change from A to B directly without having B in the AS then only remove A, like example in next slides, AS change from 250 to 264.


Case #1-1 – Inter-RNC, Intra-Frequency Hardhandover (HHO)

TMSI 00 01 86 55

RNTI RN26:00 57 8 (= 1400)

RN27: 02 2E 6 (= 8934)

Time_orig 15:21:45.882

RNC_orig / CID (SC) RN26 / 22952 (258)

RNC_End / CID (SC) RN27 / 32242 (264)

• Handover Category:

• Iur Failure - Inter-RNC SRNC Relocation failure => Triggering Inter-RNC, Intra-Frequency HHO.

• Analysis:

• Iur failure was simulated / purposely disabled via blocking AAL2 User Plane, to invoke Inter-RNC, Intra-Frequency HHO.

• Solution / Action proposed:ScannerScanner

UE RSCPUE RSCP

UE Ec/NoUE Ec/No

RNTI_00000578_0157.zip

RNTI_000022E6_03EF.zip

RN26RN26

RN27RN27

Iur Failure !Iur Failure !


Case #1-2 – Inter-RNC, Intra-Frequency Hardhandover (HHO)

TMSI 00 01 86 55

RNTI RN26:00 57 8 (= 1400)

RN27: 02 2E 6 (= 8934)

Time_orig 15:21:45.882

RNC_orig / CID (SC) RN26 / 22952 (258)

RNC_End / CID (SC) RN27 / 32242 (264)

• Handover Category:

• Iur Failure - Inter-RNC SRNC Relocation failure => Triggering Inter-RNC, Intra-Frequency HHO.

• Analysis:

• Iur failure was simulated / purposely disabled via blocking AAL2 User Plane, to invoke Inter-RNC, Intra-Frequency HHO.

• Solution / Action proposed:ScannerScanner

UE RSCPUE RSCP

UE Ec/NoUE Ec/No

RN26RN26

RN27RN27


• If difference between the best AS cell and the NS cell is too high and SHO is not performed, the RRC connection is released to avoid excessive interference

• Why might an AS update not be possible?• Excessive load in the neighbor ing cell• Hard blocking in the target BTS• Unavailability of DL spreading codes• Iub transport resources unavailable

• This function is activated by EnableRRCRelease (HOPS parameter)/0=no (def),1 =yes

• The RRC connection is released if either:

AveEcNoDownlink + ReleaseMarginForAveEcNo(n) < AvEcNoNcell(n)EcNoDownlink + ReleaseMarginPeakEcNo(n) < EcNoNcell(n)

• ReleaseMarginForAveEcNo (HOPS) = average Eb/N0 margin [-6 … 6] dB, default 2.5dB• ReleaseMarginPeakEcNo (HOPS) = peak Eb/N0 margin [-6 … 6] dB, default 3.5dB

• Emergency calls are exempt from RRC Connection Release process

RRC Connection Release









Traffic Balancing

• Traffic balancing with Call setup control or during hard HO to another frequency

• Directed RRC connection setup => direct the user to the frequency with lower loading within the same sector

• A second frequency can be added for each sector/site independently as the capacity needs to be increased

f1f1 f1f1 f1f1

f2f2

f2f2 f1f1 f1f1

High capacity site

Start call on f2 Coverage reasonHandover

High capacity WCDMA sites can be utilized with RAN1.5

High capacity WCDMA sites can be utilized with RAN1.5


Directed RRC Connection Setup

If either the UL or DL load of the Source cell exceed a certain threshold value, the DRRC Connection setup process is initiated.

• CurrentCellPrxTotal > PrxTarget (default 4 dB)+ DRRCprxOffset (default -1 dB)• CurrentCellPtxTotal > PtxTarget (def. max-3 dB)+ DRRCptxOffset (default -3 dB)

• The load of the current cell (UL/DL) is compared with the load of other cells in same sector to find out cell having less load:

• CurrentCellPrxTotal > CellPrxTotal(n) - DRRCprxMargin(default -0.5 dB)• CurrentCellPtxTotal > CellPtxTotal(n) - DRRCptxMargin(default -2 dB)

• Decision of Directed RRC connection setup is done by Admission Control in RNC

• Directed RRC connection setup is used for balancing the load (UL/DL) between cells which belong to same sector

• Same sector has cells with equal primary CPICHpower, PtxTarget, PtxOffset, PrxTarget and PrxOffsetvalues

• Parameter Sector Identifier tells to which sector cellbelongs to


Site – Sector – Cell in 3G

f 1

1+1+1

2+2+2

f 1 f 2

Each WCDMA cell consits of:Load Control (LC)Admission Control (AC)Packet Scheduler (PS) / HSDPA

3 cells covering 3 sectors. 6 cells covering 3 sectors.

Sector 1

Sector 2

Sector 3

Cell 1

Cell 2Cell 3

Site „Bonn 77“

1 site (NodeB, WBTS) with 3 cells.

high capacity-site „Bonn 99“

1 site (NodeB, WBTS) with 6 cells.

Sector is meant as geographical coverage area

Cell 1

Cell 2Cell 3

Cell 4

Cell 5

Cell 6

Sector 3Sector 2

Sector 1


RACH: RRC Connection Setup Request

Cell_2 frequency 2

Cell_1 frequency 1

FACH: RRC Connection Setup

DCCH: RRC Connection Setup Complete

Cell_1 load > Cell_2 load + load threshold-> DRRC activated

Directed RRC Connection Setup - Signalling

incl. UARFCN of target cell


Technical Background – DRRC (2)

Load of Source cell Load of Target cell

0 %

60 %

NoDRRCallowed

PrxTarget PtxTarget

DRRCprxOffset (-1 dB) DRRCptxOffset (-3 dB)

0 %

60 %

DRRCprxMargin (0dB) DRRCptxMargin (-0.5 dB)

DRRCNoDRRCneeded

CurrentCellPrxTotalCurrentCellPtxTotal

PrxTargetPtxTarget

CellPrxTotal(n)CellPtxTotal(n)

DRRC

DRRC connectionsetup

DRRC connection setup to the target cell if both of the following equations are fulfilled:CurrentCellPrxTotal (source cell) > CellPrxTotal(n) – DRRCprxMargin (default 0dB)

CurrentCellPtxTotal (source cell) > CellPtxTotal(n) – DRRCptxMargin (default –0.5dB).

If either the UL or DL load of the Source cell exceed a certain threshold value, the DRRC Connection setup process is initiated.

CurrentCellPrxTotal(s) > PrxTarget(s) + DRRCprxOffset (default –1dB)CurrentCellPtxTotal(s) > PtxTarget(s) + DRRCptxOffset (default –3dB)


Basic 2nd Carrier & DRRC Parameter Settings (Example)Parameter 1st Carrier 2nd Carrier Remark

LCR ID 1,2,3 4,5,6Ptx_CPICH 33 dBm 33 dBm Cell specific. Carrier 1 & 2 must

have same value.Ptx_Target 42 dBm 42 dBm Cell specific. Carrier 1 & 2 must

have same value.Ptx_Offset 1 dB 1 dB Cell specific. Carrier 1 & 2 must

have same value.Prx_Target 30 dB 30dB Cell specific. Carrier 1 & 2 must

have same value.Prx_Offset 1 dB 1 dB Cell specific. Carrier 1 & 2 must

have same value.Sector ID As defined As defined Carrier 1 & 2 must have same

value/ sector.DRRCptxOffset - 3 dB - 3 dBDRRCptxMargin -0.5dB -0.5 dBDRRCprxOffset -1 dB -1 dBDRRCprxMargin 0 dB 0 dB

*FMCS 7 / 8HHoRscpThreshold: -95dBmHHoRscpCancel:-92dBm*FMCI 1 / 1IFHO caused by CPICH RSCP:used

GSM HO caused by CPICH RSCP:not used

Minimum Required quality level -20 dB -20 dBMinimum Required RX level -115 dBm -90 dBmSintrasearch On/12 off Off:always measureSintersearch On/2 off Off:always measureSsearchRAT On/4 On/4

FMCG (RT/NRT) 1 / 11 NA

FMCS (RT/NRT) 2 / 12 7 / 8

FMCI (RT/NRT) 1 / 11 1 / 1

These parameters MUST BE the same for cells defined as same Sector, in order for DRRC functionality to work.

These parameters MUST BE the same for cells defined as same Sector, in order for DRRC functionality to work.









Compressed Mode in UplinkGSM BTS WCDMA BTS

DL

DL CM (this should be offwhen GSM is measured)

UL CM (needed to avoid interference)

During WCDMA transmissionsignal leakage will go to GSMRx also


Compressed Mode (CM)• CM was introduced to WCDMA to allow inter-frequency (system) Handovers• CM is used to create idle periods (gaps) in the transmission during which ncell measurements on

another frequency can be made

• The reception/transmission gap is always seven slots in RN2.0. Gaps can be created using single or double frame approach (Nokia supports both)

• Because same data amount is sent in a shorter time more power is needed during CM (both in UE and BTS)

=> affects WCDMA coverage

• Fast Power control information might be lost during the gap => higher Eb/No=> affects WCDMA capacity

• Compressed frames may be lost if power control is not set correctly=> affects WCDMA quality

• CM methods are Spreading Factor Halving and Higher Layer Scheduling (both supported in RN2.0)

Normal frame Normal frame

Measurement gapMeasurement gapPower / Data Rate

CompressedMode

Normal frame

Wei Yun

Note

the gap is to allow UE to get the GSM measurement, like RSSI, etc.


Measurement Gap

Min transmitted TSs per Frame: ≥ 8

radio frame radio frame

TGL

Length of gap:3, 4, 5, 7 timeslots

Single-frame method

radio frame radio frame

TGL

Double-frame method

Length of gap:3, 4, 5, 7, 10, or 14 timeslots

The reception/transmission gap is always 7 time slots in RN2.0.

The reception/transmission gap is always 7 time slots in RN2.0.


Measurement Gap


Compressed mode methods • Halving Spreading Factor, SF/2 for RT and NRT services (UL

and DL)• Doubles temporarily the physical channel data rate, possible for all services• Needs 3 dB more UE power due to halved spreading ratio • If new channelization code is available from code tree in DL

• WCEL: AltScramblingCodeCM/0=used (def), 1=not used

• Higher Layer Scheduling, HLS (UL and DL) • Only possible for PS services (RT or NRT)• Does not cause extra load to the cell but reduces DCH user data• HLS ¾ data rate or HLS ½ data rate possible

Double frame is used in case of HLS ¾ data rateSingle frame is used in case of spreading factor halving and HLS ½ data rate.


Compressed mode parameters

• CM can be activated/deactivated by CMmasterSwitch (RNC) /0=in use (def)

• HLS rate configurable using HLSModeSelection (RNC)/def 0=1/2 HSL , 1=3/4 HSL

• Maximum number of UEs in CM is controlled through MaxNumbUECMcoverHO (RNC)/16 (range 0..255)

• The number of UEs in DL CM depends on the PtxTotal value• The number of UEs in UL CM depends on the PrxTotal value


How many UEs in Compressed Mode ?

PtxTarget/PrxTarget

DL/ULtransmission power

Load

PtxOffset/PrxOffset

New UEs can be switched to CM when:Pxx_Total < Pxx_Target &

# of UEs in CM < MaxNumbUECMcoverHO

One new UE in CM can be allowedif the limit is not reached

No new UE can be in CM here


AMR, RT PS or CS data serviceAMR, RT PS or CS data service

SF/2 used for both UL and DL

• Selection of the compressed mode method is performed in the following way:

SF/2 used for both UL and DL •compressed mode trigger parameters have to be set so that there is room for power increase due to code splitting otherwise power increase is cut and quality of connection gets worse during the compressed frames•Usage of alternative scrambling code is possible if RNP parameter AltScramblingCodeCM enables

Transmission Gap Pattern:Single frame: 7 slot gap,

variable # of normal frames



NRT PS data serviceNRT PS data service

Higher layer scheduling is usedfor both UL and DL

Higher layer scheduling is usedfor both UL and DL

Transmission Gap Pattern:Transmission Gap Pattern:

Single frame: 7 slot gap,# of normal frames

Single frame: 7 slot gap,# of normal frames

Double frame: 7 slot gap,# of normal frames

Double frame: 7 slot gap,# of normal frames

Selection between HLS ½ and HLS ¾

Selection between HLS ½ and HLS ¾

Compressed Mode Initiate Compressed Mode

Configure GSM measurements


Multi Service : AMR + PS data, AMR + CS data,

PS data + CS data

Multi Service : AMR + PS data, AMR + CS data,

PS data + CS data

SF/2 used for both UL and DL

• Selection of the compressed mode method is performed in the following way:

SF/2 used for both UL and DL•also same power and alternative scrambling code aspects as in pure AMR or CS data service cases





• Note that same method according to service is used for all Handover triggers• Both uplink and downlink gap patterns can be used despite of whether other direction is compressed or not

• If both directions (UL and DL) are compressed, gap pattern is chosen so that both directions support it• E.g. downlink support single frame but uplink double frame, it means that double frame shall be used

• The number of normal frames between gapped frames is defined with parameters• This solution leaves the following problem in certain multi service call

• Currently UEs of certain vendor do not support in downlink DPCCH and DPDCH slot format #15B (compressed mode code splitting when SF=4)

• This means that 320 kbps PS data + AMR does not work for these terminals • This problem can be partly avoided by denying compressed mode with that high data rate

• It can be done in downlink with RNP parameter HHOMaxAllowedBitRateDL

Compressed Mode Initiate Compressed Mode

Configure GSM measurements


Compressed mode

• The normal compressed mode strategy includes fewer combinations of compressed mode configurations

• The non-configurable RNC parameter CompressedModeStrategy is used to select between the two strategies

• This parameter is configured to apply the normal strategy

• The normal strategy has been selected to minimise system complexity while the quantity of field experience is relatively low

CM Method SF/2AMR Speech RT Data

SF/2NRT Data

½ or ¾ Rate HLS









IFHO/ISHO Process Overview

HO Triggering Thresholds set in RNCHO Triggering Thresholds set in RNC

Event Triggered Coverage/Capacitybased HO fulfilled in RNC

Event Triggered Coverage/Capacitybased HO fulfilled in RNC

RNC commands selected UE(s) to startIF/IS measurements

RNC commands selected UE(s) to startIF/IS measurements

Measurements are done in Compressed Mode (CM)

Measurements are done in Compressed Mode (CM)

UE reports GSM cells withstrongest RSSI signals to RNCUE reports GSM cells with

strongest RSSI signals to RNC

RNC makes HO decision andcommands UE to target cell

RNC makes HO decision andcommands UE to target cell

RSSI measurements and BSICverification for GSM cells

RSSI measurements and BSICverification for GSM cells

Different decision methods for IF HOOnly one decision method for IS HO

5 Coverage/Capacity HO Reasons

About 25 HO parameters

Reporting cells are active set cells (max 3) + max 6 IFHO, max 6 ISHO neighb.

Max 32 neighbor s could be measured

(31 Intra-Freq neighbor s)48 Inter-Freq neighbor s 32 Inter-System neighbor s can be measured


IFHO/ISHO measurements- difference• IF measurements

• IS measurements

• BSIC verification required in case neighbor list includes multiple GSM neighbor s using the same RF carrier

WCDMA

IS-HOMeasurement

Trigger Target Cell found

RSSI meas. BSIC verification

IS-HODecision

WCDMA

IF-HOMeasurement

TriggerTarget Cell found

IF -measurements

IF-HODecision

Wei Yun

Note

e1f

Wei Yun

Note

only for CS call for PS, only need RSSI measurement and perform cell change order, BSIC verification is needed when BSIC collision happen









IF/IS Handover Triggering Reasons

4. DL DPCH approaches itsmaximum allowed powerFMCI: IFHOcauseTxPwrDLFMCG: GSMcauseTxPwrDL

5. Quality deterioration report from UL outer loop PCFMCI: IFHOcauseUplinkQualityFMCG: GSMcauseUplinkQuality

3. UE Tx power approaches itsmaximum allowed power, event 6A/6DFMCI: IFHOcauseTxPwrULFMCG: GSMcauseTxPwrUL

2 . Low measured absoluteCPICH RSCP, events 1E/1FFMCI: IFHOcauseCPICHrscp, FMCG: GSMcauseCPICHrscp

1. Low measured absolute CPICH Ec/No, event 1E/1FFMCI: IFHOcauseCPICHEcNoFMCG: GSMcauseCPICHEcNo

HO trigger

6 . Others (Not implemented in RAN 1.5):e.g. Traffic & load reason IS-HO, etc

Frequency Measuring Control for Inter-Frequency = FMCIFrequency Measuring Control for Inter-System (GSM) = FMCG

Wei Yun

Note

currently not setting this


1. Measurement trigger CPICH Ec/NoReporting event: 1E: A P-CPICH exceeds an absolute threshold (triggered if one)

1F: A P-CPICH falls below an absolute threshold (triggered if all)

time

Cell 1 Cell 2

Cell 3

absolutethreshold

e.g.

P-C

PICH

Ec/

No

1E: HHoEcNoCancel

1E: HHoEcNoCancelTime

1F: HHoEcNoThreshold

1F: HHoEcNoTimeHysteresis


1. Measurement trigger CPICH Ec/No

• RNC starts IF/IS measurement when event 1F occurs for all cells in the active set: A Primary CPICH becomes less than an absolute threshold

• RNC stops IF/IS measurement when event 1E occurs for at least one cell of the active set : A Primary CPICH becomes better than an absolute threshold

• Note:IF/IS measurements can be stopped if event 1Fs are cancelled by events 1E only when IFHO/ISHO was not successful and only inside the time between CM measurements, specified by the time InterFreqMinMeasIntervalGsmMinMeasInterval/default 10s, recommendation 2s .

• Filtering applied before event evaluation in the UE:• FMCS: EcNoFilterCoefficient/0= 200ms filtering period


1. Measurement trigger CPICH Ec/No• Event 1E parameters:

• Triggering conditions: Active set cells• Hysteresis: not used in 1F• Threshold used frequency: FMCS : HHoEcNoCancel/ -20 dB• Time-to-trigger: FMCS: HHoEcNoCancelTime/ 1280 ms• Amount of reporting: infinity• Reporting interval: not applied• Reporting cell status: max 3 active cells

• Event 1F parameters:• Triggering conditions: Active set cells• hysteresis: not used in 1F• Threshold used frequency: FMCS : HHoEcNoThreshold / - 22 dB (range 0..-24 dB)• Time-to-trigger: FMCS: HHoEcNoTimeHysteresis / 640 ms (range 0..5000ms)• Amount of reporting: infinity• Reporting interval: not applied• Reporting cell status: max 3 active cells

Wei Yun

Note

now set -12

Wei Yun

Note

now set -9


2. Measurement trigger CPICH RSCP

• UE continually monitors pilot channels of BTSs in AS

• If RSCP of a Node B falls below threshold, HHoRscpThreshold, UE sends event 1F report

• RNC starts IF/IS measurements when event 1F occurs for all cells in AS

• RNC stops IF/IS measurements when event 1E occurs for at least one cell of AS

• Note:IF/IS measurements can be stopped if event 1Fs are cancelled by events 1E only when IFHO/ISHO was not successful and only inside the time between CM measurements, specified by the time InterFreqMinMeasIntervalGsmMinMeasInterval/default 10s, recommendation 2s .

• UE filtering applied before event evaluation using HHoRscpFilterCoefficient (FMCS) /200ms, range 200…1600ms


2. Measurement trigger CPICH RSCP• Event 1E (A primary CPICH exceeds an absolute threshold) parameters:

• Triggering conditions: Active set cells• hysteresis: not used in 1E• Threshold used frequency: (FMCS) : HHoRscpCancel/ - 100 dBm• Time-to-trigger: (FMCS): HHoRscpCancelTime/ 1280 ms• Amount of reporting: infinity• Reporting interval: not applied• Reporting cell status: max 3 active cells

• Event 1F (A primary CPICH falls below an absolute threshold) parameters:• Triggering conditions: Active set cells• Hysteresis: not used in 1F• Threshold used frequency: HHoRscpThreshold (FMCS)/ - 105 dBm• Time-to-trigger: HHoRscpTimeHysteresis (FMCS)/ 640 ms• Amount of reporting: infinity• Reporting interval: not applied• Reporting cell status: max 3 active cells

Wei Yun

Note

now set -102dBm


Reporting Events 6A, 6B and 6D

timetime totrigger

UE T

xPo

wer

UE Transmitted Power Tx Threshold

6B6A

6Dmin(UEtxPowerMaxDPCH, P_MAX)

6A: The UE Tx power exceeds an absolute threshold 6B: The UE Tx power falls below an absolute threshold 6D: The UE Tx power reaches its maximum value

InterfreqUETxPwrTimeHystGSMUETxPwrTimeHyst


3. Measurement trigger UE Tx Pw (UL Coverage)

• RNC orders IF/IS measurements when one of the following event occurs:• Event 6A: The UE Tx power becomes larger than an absolute threshold• Event 6D: The UE Tx power reaches its maximum value

• Also GSM measurements could be measured first depending on UE Tx power values in IFHO and ISHO parameters

• Only lower threshold is send to UE, so either WCDMA or GSM is measured first, but also other RAT could be measured if not good enough neighbor is found

• In addition, the UL data rate allocated to the user must not exceed WCEL: HHoMaxAllowedBitrateUL/32 kbits/s

• RNC calls off inter-frequency measurements when event 6B occurs: the UE Tx power becomes less than an absolute threshold.

• Filtering applied before event evaluation in the UE.• FMCI : InterfreqUETxPwrFilterCoeff/8=10ms (range 10..480ms)• FMCG: GSMUETxPwrFilterCoeff/8 =10ms (range 10..480ms)

• NOTE: Not all UE vendors support 6A event


3. Measurement trigger UE Tx Pw (UL Coverage)• Event 6A parameters:

• Time-to-trigger: 0s• UE Transmitted Power threshold = min (UEtxPowerMaxDPCH, Pmax) –

UE_TX_POWER_threshold• UEtxPowerMaxDPCH is the maximum allowed UL tx power on DPCH in the active

cell (range -50..24 dBm, step 1, default 21 dBm), Pmax is the maximum RF output power

• UE_TX_POWER_Threshold depends on the type of service:• FMCI: InterfreqUETxPwrThrAMR/-3 dB (range -10..0, step1)• FMCI: InterfreqUETxPwrThrCS/-3 dB (same range and step)• FMCI: InterfreqUETxPwrThrNrtPS/-3 dB • FMCI: InterfreqUETxPwrThrRtPS/-3 dB • FMCG: GSMUETxPwrThrAMR/CS/NrtPS/RtPS -1/-3/-1/-3/ dB

• Event 6B parameters: time-to-trigger• FMCI: InterfreqUETxPwrTimeHyst/1280 ms • FMCG: GSMUETxPwrTimeHyst/1280 ms

• Event 6D parameter: time-to-trigger: 0s


DL_code_PWR > Ptx_RL_max + DL_DPCH_TXPWR_Thresholdexample: -100dBm > 33dBm+XXX+(-1dB)

4. Measurement trigger DL DPCH (DL Coverage)• RNC orders UE to make IF/IS measurements when DL TX power of a single radio link reaches threshold

defined as:

NOTE: Either WCDMA or GSM will be measured, not both systems

• DL_CODE_PWR = measured DL code power

• Ptx_RL_max = CPICH Pwr + MAX_DL_DPCH_ TXPWR• CPICH Pwr = Tx power of the CPICH of an active cell. PtxPrimaryCPICH (serving RNC) or

AdjsCPICHTxPwr (drifting RNC)/33 dBm, range -10…50 dBm, step 0.1 dBm• MAX_DL_DPCH_TXPWR = maximum transmission power level of the DPDCH symbols a

base station can use on the DPCH, expressed as a relative value to the CPICH pw

• DL_DPCH_TXPWR_Threshold = depends on the service type• FMCI: InterfreqDLTxPwrThrAMR/CS/RtPS/NrtPS -1/-3/-3/-1 dB (range -10 dB..0, step 0.5

dB)• FMCG: GSMDLTxPwrThrAMR/CS/RtPS/NrtPS -1/-3/-3/-1 dB (range -10 dB..0, step 0.5 dB)

• In Addition, the DL data rate allocated to the user must not exceed• WCEL: HHoMaxAllowedBitrateDL


4. Measurement trigger DL DPCH (DL Coverage)

Node BRNC

DCH Data Frame

IubUE

PO1TPC

Pilotbits not used

TFCIData 2 bitsData 1 bits

PO2DL_CODE_PWR

≥ Ptx_RL_max+ DL_DPCH_TXPWR_THRESHOLD

Max Power on DPCH (e.g. 33 dBm)

Serving WCDMA cell

time

It‘s time to triggerHO measurements

in the UE

e.g. Radio Link Measurement Report(e.g. Transmitted Code Power Value)

HHoMaxAllowedBitrateDL

Example Speech:Power Data Bits > 33dBm + (-3dB) + (-1dB)

Power Data Bits > 29 dBm (~1W)

Max Power on Channel


5. Measurement trigger UL Quality

• RNC starts IF/IS measurements based on UL outer-loop power control reports (see Module 3 Outer-loop PC)

• Enable reports from Outer-loop Power Control Controller to trigger IF/IS HO, RNC: EnableULQualDetRep/default 0=no, 1=yes

• Time duration for which BER/BLER target has not been reached, despite SIR target at maximum level, RNC: ULQualDetRepThreshold/0.5 s, 0.5..5, step 0.5s

• Periodic report, every RNC: ULQualDetRepThreshold seconds, while BLER/BLER target is not reached

• In addition, the UL data rate allocated to the user must not exceed WCEL: HHoMaxAllowedBitrateUL (default value: 32 kbits/s)

See Module 3 Channels & PowerControlSee Module 3 Channels & PowerControl


5. Measurement trigger UL QualityTa

rget

SIR

Max SIR target

Min SIR target

Actual SIR target

1st Quality deterioration report from PC to HC inside RNC

2nd Quality deterioration report (while the condition issatisfied the message is periodically repeated)

default 0.5s time

ΔSIRΔSIR

RNC

ULQualDetRepThreshold (recommendation 0.5s)

EnableULQualDetRepHHoMaxAllowedBitrateUL

RNC









Decision Algorithm

UE Tx Power (Event 6A\6B)•Threshold:InterFreqUETxPwrThrXX•L3 filter:InterFreqUETxPwrFilterCoeff *•Hysteresis margin (time to trigger):InterFreqUETxPwrTimeHyst *•Data rate thresholdHHOMAxAllowedBitrateUL *

UL Quality•Timer:ULQualDetRepThreshold•Data rate thresholdHHOMAxAllowedBitrateUL

DL DPCH power•Threshold:InterFreqDLTxPwrThrXX

•Data rate thresholdHHOMAxAllowedBitrateDL

(XX=AMR,NrtPS,RtPS)

CPICH RSCP (Event 1F)•Thresholds:HHoRscpThresholdHHoRscpCancel•L3 filter:HHoRscpFilterCoefficient *•Time to trigger:HHoRscpTimeHysteresis *HHoRscpCancelTime *

CPICH Ec/Io (Event 1F)•Thresholds:HHoEcNoThresholdHHoEcNoCancel•L3 filter:EcNoFilterCoefficient *•Time to trigger:HHoEcNoTimeHysteresis *HHoEcNoCancelTime *

AdjiPlossMarginAdjiMinEcNoAdjiMinRSCPAdjiTxPwrDPCHAdjiEcNoMargin

InterFreqMaxMeasPeriod *InterFreqMeasRepInterval *InterFreqNcellSearchPeriod * InterFreqMinHoInterval *InterFreqMinMeasInterval * InterFreqMeasAveWindow *

Handover Triggering

Handover Execution

IF HO meas control parameters

(* = parameters already optimised)

IF HO Parameters

(in blue = parameters under study)

1 more IFHO triggers in RAN04:

• IMSI basedIFHO


IFHO measurements• After HO triggering message is sent to RNC, a RRC message ”Measurement Control” is

sent to UE containing details of the measurement that the UE must execute. Measurement reporting is periodical. Max 6 IF cells can be reported. No filtering in measurements by UE.

• Upon reception of the measurements reported by the UE, RNC applies a sliding averaging window to the CPICH Ec/No & CPICH RSCP measurements. The averaged levels are used as input to the inter-frequency decision algorithm.

• From each cell in active set (max=3) also intra-frequency measurements are done at same time

RNCRRC: ”Measurement control ” message

("carrier 2" measurements)

UE

RNC

CPICH Ec/No and CPICH RSCP measurements are reported through ”Measurement report” messages

UE

RRC: ”Measurement report”


In one measurement report there is both intra-and inter-frequency

results, no measurement filtering is used in UEAdjiMeasRepInterval

(default 0.5s)

3 neighbor info send to UE:UTRA RF channel, cell

individual offset (Ec/No) and primary scrambling code


Measurement Control Parameters: FMCI

• InterFreqMeasRepInterval: 0.5 seconds• This is the interval between measurement reports, which are sent to BTS

• InterFreqMinMeasInterval:10 s• This is Minimum Measurement Interval, wait time when the following CM starts,

In case of an unsuccessful IFHO attempt, the network will deactivate compressed mode for a time period given by this parameter, thus better value will be 2 s to speed up the reactivation of CM.

• InterFreqMeasAveWindow: 6• This is Measurement Averaging Window size, sliding window is used

• InterFreqMaxMeasPeriod: 20 reports• This is Maximum Measurement Period which determines the maximum allowed

duration of the inter-frequency measurement• If the RNC is not able to execute an inter-frequency Handover, it shall stop the

inter-frequency measurements after the UE has sent the predefined number of measurement reports to the RNC.

Wei Yun

Note

CHT set 2s for inter-system


Measurement Control Parameters: FMCI• Maximum allowed duration of the inter-frequency measurement is calculated:

• InterFreqMeasRepInterval * InterFreqMaxMeasPeriod (0.5*20s) =10s,

• This seems to be too long time, because CM time was noticed to be about 3 seconds, so it makes senses to reduce the value of this parameter to some value about 3 seconds, otherwise, if there is failure, the network will not deactivate compressed mode until the timer of 10 seconds has expired. Thus, decreasing the parameter value will allow the UE/network to initiate a new IFHO attempt. Proposed value for GSMMaxMeasPeriod is 6

• This seems to be too long time, because the CM time was noticed to be about 3 s, thus proposed value for InterFreqMaxMeasPeriod is 6

• InterFreqNcellSearchPeriod:0 • This is neighbor cell search period parameter, IFHO is not allowed until the are

enough measurement reports given by this parameter• O means that only 1 measurement result is enough for decision making• Duration of the cell search period is calculated:

InterFreqMeasRepInterval * InterFreqNcellSearchPeriod).


Decision Algorithm

UE Tx Power (Event 6A)•Threshold:GsmUETxPwrThrXX•L3 filter:GsmUETxPwrFilterCoeff•Hysteresis margin:GsmUETxPwrTimeHyst•Data rate threshold

HHOMAxAllowedBitrateUL

UL Quality•Timer:ULQualDetRepThreshold•Data rate threshold

HHOMAxAllowedBitrateUL

DL DPCH power•Threshold:

GsmDLTxPwrThrXX•Data rate threshold

HHOMAxAllowedBitrateDL

(XX=AMR,CS,NrtPS,RtPS)

CPICH RSCP (Event 1F)•Thresholds:HHoRscpThresholdHHoRscpCancelL3 filter:HHoRscpFilterCoefficient•Timers:HHoRscpTimeHysteresisHHoRscpCancelTime

CPICH Ec/Io (Event 1F)•Thresholds:HHoEcNoThresholdHHoEcNoCancel•L3 filter:Done already for SHO•Timers:HHoEcNoTimeHysteresisHHoEcNoCancelTime

AdjgTxPwrMaxTCHAdjgRxLevMinHO (n)GsmMeasAveWindow

GsmMeasRepIntervalGsmNcellSearchPeriodGsmMinMeasIntervalGsmMaxMeasPeriod

Handover Triggering

Handover Execution2G-to-3G back prevention

GsmMinHoInterval

GSM measurement reporting

ISHO parameters

2 more ISHO triggers in RAN04:

• Emergency ISHO (EMISHO)

• IMSI basedISHO


ISHO measurements• After HO triggering message is sent to RNC, a RRC message ”Measurement Control” is

sent to UE containing details of the measurement that the UE must execute. Measurement reporting is periodical. Max 6 GSM cells could be measured by UE and reported to RNC. No filtering in measurements by UE

• Upon reception of the measurements reported by the UE, RNC applies a sliding averaging window to the RXLEV measurements. The averaged levels are used as input to the IS-HO decision algorithm.

RNCRRC: ”Measurement control ” message

(GSM RSSI measurements)

UE

RNC

RXLEV measurements are reported through”Measurement report” messages

UE



The first measurement report has info from the best GSM cell:

BCCH freq & RSSI, no filteringused in UE

GsmMeasRepInterval(default 0.5s)


ISHO Signalling

RRC: Measurement controlwith IE TGMP=”GSM RSSI”

RRC: Measurement report

. .

UE

ISHO triggered: Event 6A/1F/

RRC: Measurement controlwith IE TGMP=”GSM BSIC”

Handover from UTRAN

... .

RRC: Measurement report : BSIC decoded

RRC: Measurement report: BSIC no decoded

RNC

Wei Yun

Note

between this 2 steps should have network send reconfig message to UAE for compresses mode


Measurement Control Parameters: FMCG• GSMMeasRepInterval: 0.5 seconds

• This is the interval between measurement reports, which are sent to BTS• This parameter should be kept to 0.5 seconds. Increasing the reporting interval

would increase the IS-HO process delay.

• GSMMinMeasInterval:10 s• This is Minimum Measurement Interval, wait time when the following CM starts.

In case of an unsuccessful IS-HO attempt, the network will deactivate compressed mode for a time period given by this parameter, thus better value will be 2 s to speed up the reactivation of CM.

• GSMMeasAveWindow: 6• This is Measurement Averaging Window size, sliding window is used

• GSMMaxMeasPeriod: 20 reports• This is Maximum Measurement Period which determines the maximum allowed

duration of the inter-sytem measurement• If the RNC is not able to execute an inter-system Handover, it shall stop the

inter-system measurements after the UE has sent the predefined number of measurement reports to the RNC.


Measurement Control Parameters: FMCG• Maximum allowed duration of the inter-system measurement is calculated:

• GSMMeasRepInterval * GSMMaxMeasPeriod (=0.5*20s) =10s,

• This seems to be too long time, because based on field measurements BSIC and RSSI delays are about 3 seconds, so it makes senses to reduce the value of this parameter to some value about 3 seconds, otherwise, if the BSIC or RSSI measurements fail or if the IS-HO execution is not possible to due low GSM RSSI levels, the network will not deactivate compressed mode until the timer of 10 seconds has expired. Thus, decreasing the parameter value will allow the UE/network to initiate a new IS-HO attempt. Proposed value for GSMMaxMeasPeriod is 6

• GSMNcellSearchPeriod: 0 • This is neighbor cell search period parameter, ISHO is not allowed until the are

enough measurement reports given by this parameter• O means that only 1 measurement result is enough for decision making• Duration of the cell search period is calculated: • GSMRepInterval * GSMNcellSearchPeriod).

Wei Yun

Note

error!! According Nokia calculation, should be (GSMMeasRepInterval*GSMMaxMeasPeriod) + (4*GSMMeasRepInterval) = (0.5*20) + (4*0.5) = 12s


ISHO: BSIC Verification• After the selection of the target GSM cell, the RNC sends to UE the RRC message

"Measurement control” which includes details to measure ”BSIC” .

• UE stops RSSI measurements and updates the transmission gap pattern to the pattern used for BSIC decoding. The measurement reports are sent periodically to RNC.

• If the UE is unable to decode the BSIC during the given period, the BSIC measurement operation is aborted.

RNC

RRC: ”Measurement control ” message (BSIC decoding)

WCDMA

IS-HO trigger Target Cell foundIS-HO

command

RSSI meas. BSIC verification

•Numbers of GSM cells in the neighbor cell list

•Reporting interval•Sliding averaging window•Transmission gap pattern forRSSI measurements

TBSIC depends on :

•Transmission gap pattern forBSIC decoding

TRSSI depends on


Inter System Handover 3G -> 2G TuningRNC


RRC: ”Measurement report”GsmMeasRepInterval (default 0.5s)GSMMaxMeasPeriod

Max 6 GSM cells reported RRC: ”Measurement report”


RRC: ”Measurement Control”

Handover Command

Handover CompleteHandover Failure

•Inter-system measurement stops if RNC has not been able to perform inter-system handover after GSMMaxMeasPeriod (value 10, default =20, 1…20, step 1 meas report)•RNC could not initiate inter-system measurements if:

•The UE has « recently » performed an inter-system HO:GSMMinHoInterval / 10s, 0…60, step 1s•An inter-system HO « recently » fails for this UE: GSMMinMeasInterval /10s, 0…60, step 1s

Triggering

Details about the measurements

The first measurement report has info from the best GSM cell:

BCCH freq & RSSI, no filteringused in UE


ISHOInter System Handover 3G -> 2G Tuning

• There is a large number of parameters to optimize• However, part of the inter-system handover optimization was done empirically, based on

verification measurements done previously

2. GSM Measurement reporting process• GsmMeasRepInterval (default value=0.5 seconds)

• The GSM measurement reporting interval given by this parameter should be kept to 0.5 seconds (default value)

• Increasing the reporting interval would increase the IS-HO process delay• Besides, accuracy requirements related to the GSM measurements in compressed mode

are given for a reporting interval of 0.5 seconds (480ms TS 25.133)

• GsmMaxMeasPeriod ( default value = 20 measurement reports)• This parameter controls the maximum compressed mode duration time for each GSM

RSSI and BSIC decoding measurement process. The duration of this parameters in seconds is given by:

max_meas_time (s) = GsmMaxMeasPeriod x GsmMeasRepInterval + 4 x GsmMeasRepInterval

• Thus, the default value of max_meas_time in seconds is 12sec• it was found (based on field measurements) that BSIC and RSSI delays are below 3 seconds, it makes

senses to reduce the value of this parameter to some value about 3 seconds, otherwise, if the BSIC or RSSI measurements fail or if the IS-HO execution is not possible to due low GSM RSSI levels, the network will not deactivate compressed mode until the timer of 12 seconds has expired

• Thus, decreasing the parameter value will allow the UE/network to initiate a new IS-HO attempt

AMR









It is not sufficient to have triggers, which detect that a Handover has to be done. Criteria are required to decide, whether to carry out an intra-frequency, inter-frequency, or inter-RAT Handover – if there is the possibility for a Handover at all!

Conditions shown here have to be satisfied, before an inter-frequency Handover can be conducted. The best neighbor ing cell must fulfil following criteria („best“ according to Ec/No):

• Quality Criterion in case trigger was DL DPCH Power or CPICH Ec/No:AVE_RSCP_NCELL (n) > AdjiMinRSCP(n) + max(0, AdjiTxPwrDPCH(n) - P_MAX)

Signal level from new cell > required Signal level in new cell + adjustment due to allowed power

AVE_EcNo_NCELL (n) > AVE_CPICH_EcNo + AdjiEcNoMargin(n)EcNo on new cell better than EcNo in old cell + margin

• Pathloss Criterion in case trigger was UE Tx Power, CPICH RSCP or UL DPCH Quality:AVE_EcNo_NCELL (n) > AdjiMinEcNo(n)

EcNo on new cell better than required EcNo in new cell (default –14 dB)

CPICH_POWER - AVE_CPICH_RSCP > CPICH_POWER_NCELL (n) - AVE_RSCP_NCELL (n) + AdjiPlossMargin(n)

PathLoss in old cell > PathLoss in new cell + Margin (default 2 dB)(continued)

IFHO Decision


RRC: MEASUREMENT CONTROL (IF meas details)

UEISHO triggered: Event 6A\1F….

RNC

RRC: MEASUREMENT REPORT (Event 6A\1F..)

RRC: MEASUREMENT CONTROL (CFN, TGPS)

RRC: MEASUREMENT REPORT (CFN, TGPS)

Radio Link Setup

Periodic IF measReporting

RRC: PHYSICAL CHANNEL RECONFIGURATION (Timing Indication)

RRC: PHYSICAL CHANNEL RECONFIG COMPLETE

.

. Handover Decision

Compressed Mode Activation

RNC commandsIF measurements

and Compressed Mode

There is bad qualityconditions in the link ..

IF HO Signalling

With the informationgotten, the RNC assessthe best cell, and decides to attempt a IFHO to it


Inter-frequency HO – Quality Criteria

HO?

a) AVE_RSCP_NCELL (n) > AdjiMinRSCP(n) + max(0, AdjiTxPwrDPCH(n) – P_MAX)b) AVE_EcNo_NCELL (n) > AVE_CPICH_EcNo + AdjiEcNoMargin(n)

AdjiMinRSCP(n)

☺

max(0, AdjiTxPwrDPCH(n) - P_MAX)

b)

AdjiMinEcNo(n)

AdjiEcNoMargin(n)☺

AVE_EcNo_NCELL (n)

a)AVE_EcNo_NCELL(n) >AVE_CPICH_EcNo + AdjiEcNoMargin(n)


Inter-frequency HO – Pathloss Criteria

a) AVE_EcNo_NCELL(n) > AdjiMinEcNo(n)b) CPICH_POWER - AVE_CPICH_RSCP

> CPICH_POWER_NCELL(n) - AVE_RSCP_NCELL(n) + AdjiPlossMargin(n)

best active setcell

AdjiPlossMargin(n)

☺

best inter-frequencycell

b)AVE_EcNo_NCELL (n) > AdjiMinEcNo(n)

AdjiMinEcNo(n)

☺

a)









AdjgRxLevMinHO(n)

max(0, AdjgTxPwrMaxTCH(n) - P_max)

☺

AVE_RXLEV_NCell(n) > AdjgRxLevMinHO(n) + max(0, AdjgTxPwrMaxTCH(n) - P_max)

GSM cell

ISHO Decision








Wei Yun

Note

GSM -> WCDMA


Load based Handover GSM -> WCDMA

100%

80%

0%

Load reason Handoversfor speech

Load of GSM cell

Packet Data to WCDMAregardless of GSM load

Packet Data to WCDMAregardless of GSM load

Speech to WCDMAonly with high GSM load

Speech to WCDMAonly with high GSM load

Higher bit ratesfor data users

Higher bit ratesfor data users

More capacity for speech

More capacity for speech

Packet BCCH parameters can be usedto push GPRS mobiles to WCDMA

Packet BCCH parameters can be usedto push GPRS mobiles to WCDMA


GSMGSM

GSMGSM

Load and Coverage Reason Handover

GSMGSM

GSM highloaded

WCDMA lowloaded

GSMGSM GSMGSM

WCDMAWCDMA WCDMAWCDMA

Load reason Handover for speech and for HSCSD

Load reason Handover for speech and for HSCSD

WCDMAWCDMA GSMGSM

Load reason Handover

Coverage reason Handover

WCDMA can be usedto relieve GSM overload

GSM can be used to extend WCDMA coverage area

WCDMA can be usedto relieve GSM overload

GSM can be used to extend WCDMA coverage area

Mobile moving


Load based Handover Process: GSM-> WCDMA

Handover Triggering Thresholds set in BSCHandover Triggering Thresholds set in BSC

Inter-RAT measurements starts in case The RXLEV of the serving cell is above or

below the given threshold Qsearch_C

Inter-RAT measurements starts in case The RXLEV of the serving cell is above or

below the given threshold Qsearch_C

Handover Decision is done in case ofLoad of the serving cell > Load_Thresholdand CPICH Ec/No> min Ec/No Threshold

Handover Decision is done in case ofLoad of the serving cell > Load_Thresholdand CPICH Ec/No> min Ec/No Threshold

MS selects the target UTRAN cell based on measurement results

MS selects the target UTRAN cell based on measurement results

Handover command is send to MSCHandover command is send to MSC

In the S10.5 MS is measuring the UTRAN cells continuously if they are defined as a neighbor ,

The number of GSM neighbor reported could be 3-6 depending on the set value of parameter FDD_MULTIRAT_REPORT (0,1,2=def,3).

The load is measured in the cell level by comparing the occupied TCHs to the available TCHs (20 s interval used)

Load Threshold for Speech Calls or Transparent Data inter-RAT Handover:utranHoThScTpdc (Min Traffic Load TDHO), default = 80%minEcnoThreshold (Min CPICH EC/NO Threshold), default –15 dB

Parameters are sent from the BSC to the mobilein the Measurement Information message









Emergency ISHO (EMISHO)Directed Emergency Call Inter-system Handover directs emergency calls from UTRAN to GSM network in order to allow more accurate than Cell ID and RTT based location service.It is an optional feature and designed for US market to support FCC requirements.

Source UMTS RAN

Target GSM BSS

PSAP

GMLCGMLC

1. Emergency CallEstablishment

6. Location

2. Location Request

8. LocationRequest

9. Location

5. Positioning

3. Handover to GSM7. Location

Route of call before handover

Route of call after handover

4. Location Request

3G MSC

2G MSC


EMISHO Call-Flow

RANAP: Location Reporting Control

NBAP: Dedicated Measurement Init Req

RRC: Measurement Control UE Tx-Rx

NBAP: Dedicated Measurement Init Resp

RRC: Measurement Report Tx-Rx

Location Calculation based on CId and RTT

ISHO measurements & HO to GSM

Case a) ISHO to GSM is successful, no response to MSS

Case b) ISHO to GSM is not successful:RANAP: Location Report

Report Area IE: Geographical AreaClient Type IE: Emergency Call

SMLC

Radio Bearer setup

In case ISHO to GSM fails, RNC keeps location based on CI+RTT in mind

and sends RANAP:Location Report*

*









Forced Handover for AMR Voice Call

• Feature can be used to push

3G AMR calls to 2G

• Extreme parameter setting

for ISHO trigger cause

“UE Tx power” (event 6A)

WCDMA

GSM

AMR voice call setup in 3G

forced handoverto GSM

[..]UE RNC

RRC: RadioBearerSetup

RRC: RadioBearerSetupComplete

RRC: MeasurementControl

RRC: MeasurementReport (event 6A)

FMCG: GSMcauseTxPwrUL

FMCG: GsmUETxPwrThrAMR

ISHO measurements & HO to GSM

UE immediately answers

with Measurement Report

„push“ means Handover, not Directed-Retry !


Forced Handover for AMR Voice Call

• GSMcauseTxPwrUL

• Range and step: 0 (False), 1 (True)

• Indicates whether a handover to GSM caused by high UE TX power level is enabled. The handover is enabled when the value of the parameter is "Used“

• To enable feature, setting must be 1 (True)

• GsmUETxPwrThrAMR

• Range and step: -60..0 dB

• This parameter determines the UE TX power threshold for a CS voice connection. If the handover to GSM caused by high UE TX power level is enabled, the RNC starts inter-RAT (GSM) measurements when the UE TX power reaches this threshold. The UE TX power threshold is relative to the maximum TX power level an UE can use on the DPCH in the cell (or the maximum RF output power capability of the UE, whichever is lower

• To enable feature, setting must be –60 dB









Cell Reselection List

GSM MS starts WCDMA measurements if :RLA_C< F(Qsearch_I) for 0<Qsearch_I<=7

orRLA_C> F(Qsearch_I) for 7<Qsearch_I<=15

If, for suitable UMTS cell & for a period of 5 s:

CPICH RSCP > RLA_C + FDD_Qoffset

CPICH Ec/No ≥ FDD_Qmin

no prioritiesbetween WCDMA neighbor s

Measurement Updates:• RLC_C value of the serving cell• + least 6 strongest non serving GSM cells

at least every 5 s

check

and

WCDMA cellreselection

BCCH: FDD_Qmin, FDD_Qoffset

Fdd_Qoffset: selectallways (value is -infinity)

FDD_Qmin= -13 dB

Cell Reselection 2G -> 3G


• Re-selection measurements are controlled by the parameter threshold to search WCDMA RAN cells (QSRI)

• The parameter defines a threshold and also indicates whether these measurements are performed when RLA_C (a running average of received signal level) of the serving GSM cell is below or above the threshold


GSM MS starts WCDMA measurements in case running average signal (RLA_C) level is below or above

certain threshold:RLA_C # Qsearch _I (Non GPRS)


Cell Re-selection Parameters • Qsearch_I and Qsearch_P define the threshold for non-GPRS/GPRS (respectively)

capable UEs to measure 3G neighbour cells when a running average of the received downlink signal level (RLA_C) of the serving cell is below (0-7) or above (8-15) the threshold Value 0 1 … 6 7 8 9 10 … 14 15

dBm -98 -94 … -74 Always -78 -74 -70 … -54 Never

• FDD_Qoffset and FDD_GPRS_Offset the non-GPRS/GPRS (respectively) capable UEsadd this offset to the RLA_C of the GSM cells. After that the UE compares the measured RSCP values of 3G cells with signal levels of the GSM cells

Value 0 1 2 3 … 8 … 14 15

dBm -always -28 -24 -20 … 0 … 24 28

Always select irrespective of RSCP

value

Reselect in case RSCP > GSM RXLev (RLA_C) +28dB

If RLA_C>-94 UE starts 3G measurements

UE always measures 3G cells


Cell Re-selection Parameters• FDD_Qmin, defines minimum Ec/No threshold that a 3G cell must exceed, in order the UE

makes a cell reselection from 2G to 3G. This is the new mapping table

• FDD_REP_QUANT defines the reporting quantity for UTRAN cell (1=Ec/No or 0=RSCP, default 1). This parameter is hidden and it can not be tuned

• 3G_Search_PRIO parameter allows to extend the BSIC reporting interval from 10 s to 13s by checking the BSICs from non-serving BCCH carriers and also make WCDMA measurements as often as possible. Range is 0=no, 1=yes, default value .This parameter is hidden and it can not be tuned

• Defined in the SI2quater and PSI3quater if PBCCH is allocated

ParameterParameter

Name for Sys Info (SI)Name for

Sys Info (SI)

Qsearch_IQsearch_I

2quater2quater

Qsearch_PQsearch_P Qsearch_PQsearch_P

2quater2quater 3quater3quater

FDD_QMinFDD_QMin

2ter2ter

FDD_(GPRS)Qoffset

FDD_(GPRS)Qoffset

2quater2quater

FDD_REP_QUANT

FDD_REP_QUANT

2ter2ter

3G_search_PRIO

3G_search_PRIO

2(3)quarter(PBCCH)

2(3)quarter(PBCCH)

Fdd_Qmin mappingAif parameter 0 1 2 3 4 5 6 7Fdd_Qmin (old) [dB] -20 -19 -18 -17 -16 -15 -14 -13Fdd_Qmin (new) [dB] -20 -6 -18 -8 -16 -10 -14 -12


Cell Re-selection Example-Weaker WCDMANon GPRS case

t

Serving GSM Cell

Neighbour WCDMA Cell

Ec/NoRSCP/RLA_C

5 sec.

Cell re-selection to WCDMA

FDD_Qmin=0(-20 dB)

FDD_Qoffset =6 (-8 dB)

Qsearch_I=0 (-98 dBm)

RLA_C

Measurements starts (serving cell)

Minimum Quality Requirement for WCDMA Ec/N0

RSCP


Cell Re-selection Example-Weaker WCDMAGPRS case

t

Serving GSM Cell (Best)

Neighbour WCDMA Cell

Ec/NoRSCP/RLA_C

5 sec.

Cell re-selection to WCDMA

FDD_Qmin=-20 dB

FDD_GPRS_Qoffset =10 (8 dB)Qsearch_P=0(-98 dBm)

RLA_P

Measurements starts (serving cell)

Minimum Quality Requirement for WCDMA

Ec/N0

RSCP



• Whilst camping in a 3G cell the UE performs intra-frequency, inter-frequency, and inter-system measurements based on the measured CPICH EcNo of the serving cell according to the following rules:

• Serving cell parameters Sintrasearch, Sintersearch and SsearchRAT are compared with Squal (CPICH Ec/No - Qqualmin) in S-criteria for cell re-selection

• UE will measure neighbor cells depending on how parameters are set & send (if parameters are not sent UE shall measure all cells)

• 1 - None (Squal > Sintrasearch ) • 2 - WCDMA intra-frequency (Sintersearch < Squal ≤ Sintrasearch)• 3 - WCDMA intra- and inter- frequency, no inter-RAT cells (SsearchRAT < Squal ≤ Sintersearch) • 4 - WCDMA intra- and inter-frequency and inter-RAT cells (Squal ≤ SsearchRAT )

Sintrasearch Sintersearch SsearchRAT

WCDMACELL

1234

Wei Yun

Note

-8dB

Wei Yun

Note

should be in between -8 and -14dB

Wei Yun

Note

-16dB, changed to -14dB



First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)

Rs = CPICH RSCP + Qhyst1Rn= Rxlev(n) - Qoffset1

Rn (GSM) > Rs (WCDMA)And

Rxlev (GSM) >QrxlevMin

YesNo

Cell re-selection to GSM

Neighbour WCDMA or GSM cell calculation with offset

parameter

Serving WCDMA cell calculation, with

hysteresis parameter

UE starts GSM measurements if CPICH Ec/No < qQualMin + sSearchRAT

SintraSearch

SinterSearch

SsearchRAT

CPICH EcNo

qQualMin

Second ranking only for WCDMA cells based on CPICH Ec/No

Rs = CPICH Ec/No + Qhyst2Rn=CPICH_Ec/No(n)-Qoffset2 Cell re-selection to

WCDMA cell of highest R value



• UE ranks the serving cell and the measured neighboring cells to find out if reselection should be made

• All the measured suitable cells (S-criteria) are included in the ranking.

• Criteria for a suitable cell (S-criteria) is defined as • WCDMA intra-frequency neighbor cell:

– CPICH Ec/No > AdjsQqualmin and CPICH RSCP > AdjsQrexlevmin• WCDMA inter-frequency cell:

– CPICH Ec/No > AdjiQqualmin and CPICH RSCP > AdjiQrexlevmin• GSM cell:

– Rxlev > Qrxlevmin

• Ranking is done using Criteria R, and the UE reselects to the cell with highest R-criteria. R-criteria is defined as:

• For serving cell: Rs = Qmeas,s + Qhysts• For neighboring cell Rn = Qmeas,n – Qoffsetts,n

• Qmeas is CPICH Ec/No for WCDMA cell and RxLev for GSM cell



• There is no timer defined how long the GSM should be fulfilling the re-selection criteria

• However there is running average of 4 GSM measurements which provides some protection against ping – pong (time vice –based on DRX cycle length and as sliding window average)

• In case additional protection is needed it can be arranged by using the Qhyst1 parameter (for WCDMA serving cell RSCP) or AdjgQoffset1(for GSM neighbor ing cell RxLev)

First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)

Rs = CPICH RSCP + Qhyst1Rn= Rxlev(n) - Qoffset1


How to avoid ping pong ?• When phone is camped on 3G, GSM measurements can start when CPICH Ec/Io of

serving cell is below Ssearch_RAT + QqualMin.

• When phone is camped on GSM, cell reselection to 3G is possible if CPICH Ec/Io of the candidate is above FDD_Qmin.

• Therefore, to avoid ping pongs between 3G and GSM the following condition should be met:

FDD_Qmin >= QqualMin+Ssearch_RAT

QqualMin=-18 dB

Ssearch_RAT=4 dB

CPICH Ec/Io

FDD_Qmin >= -12 dB

QqualMin +Ssearch_RAT

tCamping on 3G Camping on GSM Camping on 3G









Inter-RNC Mobility• Most of the times the UE hands over among WBTS belonging to the same RNC (Intra-

RNC Handovers)• However, what happens when the target WBTS is under a different WBTS??• 3GPP gives two different options to handle inter-RNC mobility in WCDMA

• Anchoring: the UE will be connected to the CN via the “old” RNC. It is required Iur connection between the RNCs involved

• SRNS relocation: the UE will be connected to the CN via the “new” RNC. It is the Nokia implemented method

*) SRNS relocation needs core networksupport; UE support mandatory in 3GPP

CN

RNCRNC

Iu Iu

Iur

CN

RNCRNC

Iu Iu

Iur

AnchoringCN

RNCRNC

Iu Iu

Iur

CN

RNCRNC

Iu Iu

Iur

SRNS relocation *)


RNCRNCRNC

RNCRNC

RNC

RNCRNCRNC

RNC

SRNS Relocation

SRNS Relocation

SRNS Relocation

SRNS Relocation

SRNS Relocation

Call will drop

SRNC anchored

Anchor RNC (SRNC)

SRNS Anchoring


SRNC Relocation• The SRNC relocation is used for moving the SRNC functionality from one RNC to

another RNC, that is, closer to where the UE has moved during the communication. Both the radio access network and the core network are involved

• There are the following types of relocations• Relocation for circuit-switched services• Relocation for NRT PS services• Relocation for NRT services started by the Cell/Ura Update message from target

RNC(CELL_FACH state relocation)• Relocation for RT PS services

• An inter-RNC Hard Handover can be associated to the SRNS relocation, if so the relocation is UE involved, since the UE is ordered to switch to another carrier or to replace the whole active by sending s HHO command to the UE during the relocation procedure. An inter-RNC Hard Handover can be due to:

• Inter frequency HHO is needed, and the target cell is located in the DRNS• No resources (mainly Iur capacity) available between the involved RNCs (so no

inter-RNC SHO possible)• No Iur interface configured between the neighbour RNCs


UE not involved SRNC Relocation for RT UETarget RNC

SRNC Relocation Decision

SRNC operation started

CN

UP switching

User plane set -up

RANAP:Relocation Required

RANAP:Relocation Request

RANAP:Relocation Request Ack

RANAP:Relocation complete

RRC:UTRAN Mobility Information

RANAP:Relocation Command

RNSAP:Relocation Commit

RANAP:Relocation Detect

RRC:UTRAN Mobility Information Confirm

RANAP:Iu Release

RANAP:Iu Release Complete

User plane release

Source RNC SRNC Relocation is initiated in the Serving RNC when all the cells of the active set belong to a different RNC. The SRNC sends a Relocation Required

• The CN evaluates if the relocation is possible and in that case, it sends a Relocation Request to the target RNC with parameters for the bearer establishment

• Relocation Command sent from CN to Source RNC with UTRAN information and bearer parameters

• After that, the Source RNC sends Relocation Commit message over Iur to the Target RNC

• When target RNC starts to act as Serving RNC, it sends a Relocation Detect message to CN. This message has no parameters

• At the same time UTRAN Mobility Information is sent to the UE, to inform that the relocation is performed and should use the new RLs

• After the confirm, the target RNC informs CN with Relocation Complete –message that the relocation procedure was successful and Iu is released from source RNC

Start RelocPrep

Stop RelocPrep

Start RelocOverall

Start RelocOverall

Stop RelocOverall

Stop RelocOverall

RelocationSupport =1NrncRelocationSupport =1


UE involved: Combined SRNC Relocation and inter-RNC HHO for RT

UETarget RNC

SRNC Relocation Decision

L1 sync. Established between BTS and UE

CN

UP switching

User plane set -up

RANAP:Relocation Required

RANAP:Relocation Request

RANAP:Relocation Request Ack

RANAP:Relocation complete

Physical Ch Reconfig Complete

RANAP:Relocation Command

Physical Channel Reconfiguration

RANAP:Relocation Detect

RANAP:Iu Release

RANAP:Iu Release Complete

User plane release

Source RNC

• Because there is no Iur interface, combined SRNS relocation and HHO are done before the UE is completely under the target RNC

• The procedure is quite similar to the not UE involved case until Relocation Command

• The only difference in the Relocation Requiredmessage, the Relocation Type IE is set to "UE involved in relocation of SRNS"

• Instead of Relocation Commit via Iur, the serving RNC sends a Physical CH Reconfiguration, after which the UE stops transmitting and receiving on the old radio links and starts on the new radio link

RelocationSupport =1NrncRelocationSupport =1

Start RelocPrep

Stop RelocPrep

Start RelocOverall

Stop RelocOverall

Start RelocOverall

Stop RelocOverall

Wei Yun

Highlight


UE reconfiguration

UE moving

RRC: TRANSPORT CHANNEL RECONFIGURATION

RRC: TRANSPORT CHANNEL RECONFIGURATION COMPLETE

Change during HO: • User Plane, Bitrate• Spreading factor• Rate matchingor:

RRC: PHYSICAL CHANNEL RECONFIGURATION

RRC: PHYSICAL CHANNEL RECONFIGURATION COMPLETEChange during HO: • Scrambling Code

RANAP: Relocation Required

UE involvedI´m involved in

relocation procedureWhole AS will change..

SRNS relocation


SRNC Relocation Parameters• TRelocPrep : range = 1 ... 16 s, step 1 s, default = 6s

• Specifies the maximum time for Relocation Preparation procedure in the source RNC. The timer is set when a Relocation Required message is sent. The timer is stopped when a Relocation Command or a Relocation Preparation Failuremessage is received

• TRelocOverall : range = 1 ... 16 s, step 1 s, default = 8s• This timer is used in both source and target RNC. In the source RNC specifies the

maximum time for the protection of overall Relocation procedure. It is set in the source RNC when a Relocation Command message is received; and it is stopped when an Iu Release Command is received, or the relocation procedure is cancelled. The timer is set in the target RNC when a Relocation Request Acknowledgemessage is sent. The timer is stopped when a Relocation Complete message is sent, or the relocation procedure is cancelled

• T_Reloc_Inhibit_NRT : fixed to 5s• The timer is started in source RNC when a SRNC relocation procedure is triggered

for a NRT RAB(s) in a Cell_DCH state. The SRNC relocation procedure is inhibited as long as a DCH is used for the NRT RAB(s) or this timer expires

• TDataFwd : fixed to 4s• The timer is set when a SRNS Data Forward Command message (or a Relocation

Command message) is received from the PS CN. The timer is internally stopped in the SRNC when the SRNS Data Forwarding procedure has been completed


Parameters• IuPSrelWait3G2GMultiServ : range = 0 (10s), 1 (20s), 2 (30s), 3 (60s), 4 (120s), 5

(180s), 6 (300s), 7 (600s), default value= 4 • This RNC object parameter, controls the release of the Iu-PS connection after the

3G/2G inter-system handover with CS+PS multi-service.

When the UE does not immediately after switching to the 2G-service initiate a routing area update procedure towards the PS-CN, the RNC can keep the Iu-PS connection and wait for the RAU and the release of the CS-service in the 2G-side

When the timer expires, the RNC sends the Iu release request to the SGSN• RelocationSupport : range = 0 (Not supported), 1 (Supported), default value = 1

• RNC object parameter, identifies whether the Core Network supports the relocation of SRNC or not

• NrncRelocationSupport : range = 0 (Not supported), 1 (Supported), default = 1 • RNC object parameter, identifies whether a neighbouring RNC supports relocation

of SRNC or not








Wei Yun

Note

currently not acivated


IMSI Based Handover – Solution Overview• IMSI based Handover is optional RAN’04 feature

• The purpose of the IMSI specific Handover feature is that a mobile subscriber in a visited network can be commanded to measure selectively only specified PLMN cells and to make Handover accordingly to those specified (home or authorised) PLMNs. The input for the selective measurement control is the PLMN id that is included in the IMSI of the subscriber.

IMSI = MCC + MNC + MSIN

MCC+MNC =PLMN IDIMSI International Mobile Subscriber IdentityMCC Mobile Country CodeMNC Mobile Network CodeMSIN Mobile Subscriber Identification NumberPLMN Public Land Mobile Network

• There are four kind of IMSI based Handover:•IMSI based Intra-frequency HO•IMSI based Inter-frequency HO•IMSI based Inter-system HO•Immediate IMSI based inter-frequency/intra-frequency HO


IMSI Based HO• There is two new Management object class related to IMSI based HO

• WANE-WCDMA authorised networks• Authorized network identifier (AuthorisedNetworkId)• List of authorized networks (AuthorisedNetworkList)• Authorised network PLMN (AuthorisedNetworkPLMN)• Technology used in the authorised network (Technology)• WANE name (WANEName)

• WSG-WCDMA Subscriber group• Subscriber home PLMN (HomePLMN)• Name of subscriber home PLMN (OperatorName)• Subscriber Group identifier (SubscriberGroupID)• Identifier of the authorised network (WSGAuthorisedNetworkId)• GSM roaming allowed (GSM roaming)

• WANE set contains PLMN ids where the UE is allowed to make Handovers• WSG object maps the subscriber (PLMN id) to certain WANE set with a WANE id. A

WSG object should be created for every subscriber (PLMN id) visiting the network. • Max Number of WANEs is 10 and max number of WSGs is 128


WSG – Selecting the list of Authorised PLMNs• The RNC shall select the desired list of authorised PLMNs for the selective

measurement control on the basis of the PLMN Id that is included in the IMSI of the subscriber

• The RNC links the PLMN ID of the subscriber with the desired list of authorised PLMNs by means of an index table

PLMN 242 07 Authorised PLMN list #2

IMSI 24207XXX

PLMN 24207

Each IMSI has hard coded the PLMN that

belongs to.The WSG associates

one list number (WANE ID) to each PLMN

WSG id PLMN id List id0 24305 (Op F 3G, border

country)1

1 24201 (Op B Shared 3G) 4… … …7 24207 (Op A 3G) 28 24208 (Op B 3G) 3… … …

127IMSI 24208XXX

PLMN 24208

PLMN 242 08 Authorised PLMN list #3

MCC MNC


WANE - Structure of the Authorised PLMN lists• A list of authorised PLMNs shall contain the maximum of six PLMN identifiers

• The radio network database shall have ten separate authorised PLMN lists (WANEs)

• It is not necessary to add the home PLMN Id of the subscriber to the list of authorised PLMNs

List # Authorised PLMNs (max. 6)#1 24210 (Op D

3G)…

#2 24206 (Op A GSM

24200 (Op C 3G

24201 (Op C GSM)

24305 (Op F 3G, border country)

…

#3 24209 (Op B GSM)

24201 (Op B Sh 3G)

24210 (Op D 3G)

24306 (Op G 3G, border country)

…

#4 24208 (Op B 3G)

24209 (Op B GSM)

…

… …

#0 All …

• 'All' in the list #0 indicates that all PLMNs are considered authorised PLMNs (RNC shall combine the neighbour cell list for the inter-frequency or inter-RAT (GSM) measurement from all neighbouring cells regardless of their PLMN identifiers)


Types of IMSI Based handover

There are five kind of IMSI based Handover:

• IMSI based Intra-frequency HO (IMSIBasedSHO=enabled)

• IMSI based Inter-frequency HO (IMSIBasedIFHO= enabled)

• IMSI based Inter-system HO (IMSIBasedGsmHO= enabled)

• Immediate IMSI based Inter-frequency HO (IMSIBasedIFHO=immediate)

• Immediate IMSI based Inter-system HO (IMSIBasedGsmHO=immediate)


IMSI based Intra Frequency HO

• If at least one of the AS cells has IMSIbasedSHO enabled, then Intra Frequency HO is possible only if the PLMN ID of the monitored cell, which needs to be added, is the same as either the home PLMN ID of the subscriber or the authorized PLMNs or an AS cell's PLMN

• If none of the AS cells has IMSIbasedSHO enabled, then the monitored cell is added into the active set regardless of the PLMN IDs

• The IMSI based Intra Frequency HO does not affect the intra frequency measurement procedure: the RNC makes the neighbour cell lists for the intra-frequency measurements regardless of the PLMN IDs of the neighbour cells

• When a cell triggers the events 1A or 1C, the RNC checks whether fulfils the PLMN requirements, in that case it is added to the AS

• If a cell, that triggers the events 1A or 1C, does not fulfil the PLMN requirements and becomes the strongest (increases the interference), the RNC may release the RRC connection


Example: IMSI based Intra Frequency HO

f1 f1f1

Op ACountry X

The RNC shall be able to perform inter-PLMN handovers (SHO and IFHO) within the RNC (otherwise it will not be possible to add the green operator cell to the active set)

f1 f1f1

RNC 1(Shared Op A - Op B)

Op BBorder Country

The IMSI Intra Frequency HO is between different PLMNs -> Intra Frequency Hard Handover (there is no Iur between those RNCs)

Example 1

Example 2


IMSI based Inter Frequency/ Inter System HO

• If at least one of the AS cells has IMSIbasedIFHO/ IMSIbasedISHO enabled, then Inter Frequency / Inter System HO is possible only if the PLMN ID of the monitored cell, which needs to be added, is the same as either the home PLMN ID of the subscriber or the authorized PLMNs

• Unlike IMSI based Intra Frequency HO, the measurement list sent by the RNC in IMSI based IF/IS HO only includes the IF/IS HO cells which fulfil the PLMN requirement

• The procedure is the same for IF/IS HO causes

1. DL DPCH approaches its maximum allowed power2. Quality deterioration report from UL outer loop PC3. Low measured absolute CPICH Ec/No4. UE Tx power approaches its maximum allowed power5. Low measured absolute CPICH RSCP


IMSI IF HO Signalling

RRC: MEASUREMENT CONTROL (IF meas details)

UEISHO triggered

RNC

RRC: MEASUREMENT REPORT (Trigger Event )

RRC: MEASUREMENT CONTROL (CFN, TGPS)

RRC: MEASUREMENT REPORT (CFN, TGPS)

Radio Link Setup

Periodic IF measReporting

RRC: PHYSICAL CHANNEL RECONFIGURATION (Timing Indication)

RRC: PHYSICAL CHANNEL RECONFIG COMPLETE

.

. Handover Decision

Compressed Mode Activation

RNC commands measurements of the authorized IF cells

There is bad quality conditions in the link ..

With the information gotten, the RNC assess the best cell, and decides to attempt a IFHO to it


Immediate IMSI based Inter Frequency/ Inter System HO

• It is new cause that triggers the Inter Frequency or Inter System HO

• If at least one of the AS cells has IMSIbasedSHO enabled and IMSIbasedIFHO/ IMSIbasedISHO is set to immediate, then RNC starts a Immediate IMSI IF/IS HO in case the RNC cannot add a cell, which triggers the event 1A or 1C, into the AS, due to it does not fulfil the requirement of home/authorised/active set PLMNs

• It is possible to monitor a cell which does not fulfil the PLMN requirements because the RNC provides information about all the intra frequency cells, regardless of the PLMN IDs

• The compress mode is started and the RNC sends in a MEASUREMENT CONTROL message only information about the inter-frequency or inter-system cells whose PLMN is the same as either the home PLMN ID of the subscriber or the authorized PLMNs

• The IF HO/ISHO takes place normally


Op A IMSI

Example 1 : IMSI Based IFHO ActivatedIMSI parameters in all

RNC 1 cells

IMSIbasedGsmHO=disabledIMSIbasedSHO=disabledIMSIbasedIFHO=enabled

Authorised PLMNs

#1 10011

#2 10010

#3 10020

f2

f1 f1f1

RNC 1(Shared Op A - Op B)

RNC 2(Op A)

f2

2100213810011231002011100100

List idPLMN id

WSG id

IMSI Objects in RNC 1

Op A own cell (PLMN 10010)

Op A controlled cell shared RNC(PLMN 10011)

Op B own cell (PLMN 10010)Op B controlled cell shared RNC (PLMN 10021)

Op A

Op A

Op BOp A

RNC reports all the intra-freq cells. There is no PLMN analysis since IMSIbasedSHO=disabled, so ->

Intra Freq HO to Op B cell

One of the IFSO causes reaches its threshold, so IMSI

IFHO triggered(IMSIbasedIFHO=enabled)

and RNC sends the list of the allowed cells-> IFHO to Op A

Notice that an Op B IMSI would

behave differently in

the very same scenario!!!


Immediate IMSI HO cause conditions

1. If at least one of the AS cells has IMSIbasedSHO=enabled and IMSIbasedIFHO/ IMSIbasedISHO=immediate

2. The AS cell in question has one or more inter-frequency/inter-system neighbour cells whose PLMN ID equals either the home PLMN ID of the subscriber or a PLMN ID in the authorised list

3. The PLMN ID of a monitored cell (that has triggered the reporting event 1A or 1C) does not fulfil the requirement of the home/authorised/active set PLMNs (that is why IMSIbasedSHO=enabled is needed , otherwise it wouldn’t be possible to detect that the cell does not fulfil the PLMN requirement)


Summarizing ….IMSI Based Intra Freq HO IMSI Based IFHO/ISHO

Immediate IMSI Based IFHO/ISHO

Settings in an active set cell

IMSIbasedSHO=enabled

IMSIbasedGsmHO= enabled/

IMSIbasedIFHO= enabled

IMSIbasedSHO= enabledAND

(IMSIbasedGsmHO=immediate /

IMSIbasedIFHO= immediate)

PLMN criteria (IMSI HO trigger)

Home\ Authorised \Active set Home\Authorised

An IMSI Intra-Freq attempt to a cell that does not fulfil the Intra Freq PLMN criteria

Neighbour list sent by the RNC

All the Intra Freq cells Only the If/IS HO cells that fulfil the PLMN criteria

Only the If/IS HO cells that fulfil the PLMN criteria

PLMN criteria applied by RNC only over a cell which is

candidate to be added in the active set

Notice the Immediate IMSI HO involves 2 cell lists: (1) To fulfil the

(IMSI Intra Freq) PLMN criteria (2)Once the Immediate IMSI is triggered, the allowed PLMN IF/IS cells where the

subscriber can hand over to

It is not required for these cells to have the IMSI feature

enabled, in order to be includedin the neighbour list. Just to

have the proper PLMN ID


• IMSI-based Handover can be used in different network sharing cases• case 1: geographical sharing• case 2: common shared RAN with gateway core• case 3: mobile virtual network operator (MVNO)

• Based on IMSI, users of each operator can be handed over to their home or authorised WCDMA network from the shared area, when coverage becomes available (cases 1 and 2)

• Based on IMSI, inter-system Handovers to the user’s home or authorised GSM network can be performed in the shared area (all cases)

- inter-frequency HO to home or authorised WCDMA cell

- inter-system HO to home or authorised GSM network

IMSI-based Handovers from the shared area:

Different neighbor cell definitions in RNC for different IMSI ranges

IMSI Based HandoverExample Cases


Case 1: IMSI Based Handover andGeographical Sharing

GSM GSM GSM

GSM

WCDMA

GSM GSM GSM

WCDMA WCDMA WCDMA

WCDMA WCDMA WCDMA WCDMA

GSM GSM GSM GSM GSM

Operator A GSM cellOperator A own WCDMA cellOperator A controlled sharedWCDMA cell

Operator B GSM cellOperator B own WCDMA cell

Operator B controlled shared WCDMA cell

Operator A user path Operator B user path

Based on IMSI, load and service-based inter-

system HOs to their own GSM network in shared

area

Separate neighbor lists for different IMSI ranges (different PLMN users)

Based on IMSI, operator A user is handed over to its

own WCDMA network when coverage

becomes available

GSM

GSM

Based on IMSI, operator B user is handed over to its

own WCDMA network when

coverage becomes available

Based on IMSI, users are handed over to

their own GSM networks when

WCDMA coverage ends


Case 2: IMSI Based Handover andCommon Shared RAN

GSM GSM GSM

WCDMA

WCDMA

GSM GSM GSM

Operator A GSM cellOperator A own WCDMA cell

Common shared WCDMA cell

Operator B GSM cellOperator B own WCDMA cell


WCDMA WCDMA

Separate neighbor lists for different IMSI ranges (different PLMN users)GSM

GSM

WCDMA

GSM

GSM



area

Based on IMSI, operator A user is handed over to its

own WCDMA network when coverage

becomes available

Based on IMSI, operator B user is handed over to its

own WCDMA network when

coverage becomes available



WCDMA coverage ends


Case 3: IMSI Based Handover andMobile Virtual Network Operator

GSM GSM

GSM GSM

WCDMA WCDMA

Separate neighbor lists for different IMSI ranges (different PLMN users)

GSM

GSM

Operator A GSM cellOperator A controlled WCDMA cell

Operator B GSM cell




area



WCDMA coverage ends

Documents

07 HandoverControl 2006 Partner