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LTE eRAN3.0 Power Control Feature
Confidential Information of Huawei. No
Spreading Without Permission 1
www.huawei.com
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
LTE eRAN6.0 Power Control Feature
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Objectives
� Upon completion of this course, you will be able to:
� Describe the object of power control in LTE
� Describe the strategy and parameters of DL power control
� Describe the strategy and parameters of UL power control
� Implement the command for the parameters modidicaiton
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LTE eRAN3.0 Power Control Feature
Confidential Information of Huawei. No
Spreading Without Permission 2
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Power control overview
2. Downlink power control feature and parameters
3. Uplink power control feature and parameters
Page2
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Why Power Control in LTE
� Compensate path loss , including shadow fading and multiple
path fading
� Reduce interference on the edge cell
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LTE eRAN3.0 Power Control Feature
Confidential Information of Huawei. No
Spreading Without Permission 3
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Classification of Power Control
� According to the direction, power control is performed both
on downlink and uplink
Downlink power control Uplink power control
Cell-specific reference signalSounding RS
Synchronization signal
PBCHPRACH
PCFICH
PDSCH PUSCH
PDCCHPUCCH
PHICH
Page4
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Power control overview
2. Downlink power control feature and parameters
3. Uplink power control feature and parameters
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
DL Power Distribution
Total DL Power
Fixed setting Dynamic power control or fixed setting
RS
PSS+SSS
PBCH
PCFICH
PDCCH (SIBs/Paging/RA response scheduling
PDSCH (SIBs/Paging/RA rsponse)
PHICH
PDCCH (Dedicate UE scheduling)
PDSCH(Dedicated UE data)
Page6
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Cell Specific RS Power Setting
� EPRE: Energy Per Resource Element
� The power setting is based on EPRE
Type A Symbol: without RS REs Type B Symbol: RS REs
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Cell Specific RS Power Setting (Cont.)
� RS Power = Total power per channel(dBm) – 10lg(total
subcarrier)+10lg(PB + 1)
Bandwidth PB PRS ( dBm)
10M 1 18.2
15M 1 16.4
20M 1 15.2
3/4 1 13/4 1 1X 1 1 X3/4 1 13/4 1 1R 1 1 R3/4 1 13/4 1 1X 1 1 X3/4 1 13/4 1 1R 1 1 RPB=2 , 2 Antennas
compensate
compensate
PB Power of type B symbol / Power of type
A Symbol
1 ANT port 2 or 4 ANT ports
0 1 5/4
1 4/5 1
2 3/5 3/4
3 2/5 1/2
2 antennas, 20w per antenna
Page8
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Synchronization Signal Power Setting
� PowerSCH= ReferenceSignalPwr +SchPwr
Radio Frame
Slots
0 1 2 3 4 5 6
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Bandwidth
72
Subcarriers
PSS (Primary Synchronization
Sequence)
Repeated in
slots 0 and 10
SSS (Secondary
Synchronization Sequence)
0 1 2 3 4 5
Bandwidth
62 Subcarriers
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PBCH/PCFICH Power Setting
� PowerPBCH=ReferenceSignalPwr + PbchPwr
� PowerPCFICH= ReferenceSignalPwr + PcfichPwr
Page10
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PDCCH/PDSCH Power Setting
� In the following two status, the power for PDCCH and
PDSCH power is fixed setting
� When PDCCH carry scheduling information of common control
information (RACH response /paging indicator )
� When PDSCH carry the common info (RACH
response/SIB/paging message)
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Dynamic Power Control - PHICH
� A high probability of the UE incorrectly demodulating the
PHICH will severely affect user throughput. Power control
ensures the performance of the PHICH for all UEs while
meeting the requirements for the BER.
Estimate SINR_RS
Compare it with target SINR_RS
Adjust PHICH power
CQI Report
Page12
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Dynamic Power Control - PDCCHPDCCH dynamic power control switch
Off
Set PDCCH with fixed power
eNB measure BLER
Target BLER+
_
On
Result>0 <0
Decrease Power Increase Power
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PDSCH Power Presentation
Symbol
PPDSCH_A (power of symbol type A on PDSCH) = ρA + ReferenceSignalPwr
PPDSCH_B (power of symbol type B on PDSCH) = ρB + ReferenceSignalPwr
PA = ρA
PB = ρB / ρA
X XR RX XR Rsymbol type A on PDSCH
Su
b_
ca
rriers
symbol type B on PDSCH
Power control for the PDSCH is performed to determine PA for each UE.
Page14
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PDSCH Power Control Mechanism
Switch Setting Power Control Mechanism
DlIcicStaticSwitch: ON: or DlIcicDynamicSwitch:ON
Dynamic power control is disabled. PDSCH power is fixed setting respectively for the
Center User (CCU) and Cell Edge User (CEU).
DlIcicSwitch: OFF orDlIcicReuse3Switch:ON
andPdschPaAdjSwitch: ON
Dynamic Power control is applicable for PDSCH
DlIcicSwitch_OFF_ENUM orDlIcicReuse3Switch:ON and
PdschPaAdjSwitch: OFF
PDSCH power is fixed setting
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PDSCH Power Control - Dynamic
Page16
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Power control overview
2. Downlink power control feature and parameters
3. Uplink power control feature and parameters
Page17
LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control
ensure the random
access success
rate and latency
Minimize the
transmit power
Preamble A
Preamble B
Preamble C
eNB Initially sets PRACH preamble
expected received power
UE estimates downlink path loss
UE sets the PRACH transmit
power according eNB parameter
and path loss
If the random access preamble
attempt fails ,UE can increase the
transmit power for the next RA
preamble attempt
Page18
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Power Control
� The purpose of power control for the PRACH is to ensure the
random access success rate while minimizing transmit power
� The PRACH power is calculated using the following formula:
})1(,min{ _ stepprepreamblepreoCMAXPRACH NPLPPP ∆⋅−+∆++=
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Related Parameters
� MOD RACHCFG
� MOD CELLULPCDEDIC
Page20
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PUSCH Power Control Overview
� The purposes of power control for the PUSCH are as
follows:
� Lower interference to neighboring cells and increasing cell
throughput
� Ensure services rates for users on cell edges
� the transmit power for the PUSCH is calculated using the
following formula:
)}()())(log(10,min{)( _ ifiPLPiMPiP TFPUSCHoPUSCHCMAXPUSCH +∆+⋅++= α
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PUSCH Initial Power Determination
� The purposes of power control for the PUSCH are as
follows:
� Lower interference to neighboring cells and increasing cell
throughput
� Ensure services rates for users on cell edges
� The transmit power for the PUSCH is calculated using the
following formula:
)}()())(log(10,min{)( _ ifiPLPiMPiP TFPUSCHoPUSCHCMAXPUSCH +∆+⋅++= α
Page22
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Inner Loop Power Control- Dynamic Scheduling Service
� Inner loop
� Adjust TPC according to the transmit power density
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Closed Loop Power Control – Semi-static
� Closed loop
� Adjust TPC according to the IBLER
Page24
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Related Commands
� Algorithm Switch
� Initial power setting
Page25
LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Msg3 Power Control
� When the PUSCH carries Msg3, the transmit power of each
UE's PUSCH is calculated using the following formula:
)}()())(log(10,min{)( 3_O_pre ifiPLPiMPiP TFMsgPREAMBLEPUSCHCMAXPUSCH +∆++∆++=
Page26
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
PUCCH Power Control
� The PUCCH carries the ACK/NACK information, CQIs, and
schedule request (SR) information related to downlink data. When
the probability of incorrect demodulation on the PUCCH is high,
user throughput is severely affected.
� The purposes of power control for the PUCCH are to ensure the
PUCCH performance and reduce the interference to neighboring
cells.
� The transmit power for the PUCCH is calculated using the
following formula:
( ) )}()(,nh,min{)( _CQI_0 igFnPLPPiP PUCCHFHARQPUCCHCMAXPUCCH +∆+++=
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LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Inner Loop Power Control
� Inner loop
� Adjust TPC according to the SINR
Page28
Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Related Commands � Algorithm Switch
� Initial power setting
Page29
LTE eRAN3.0 Power Control Feature
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Copyright © 2013 Huawei Technologies Co., Ltd. All rights reserved.
Sounding RS Power Control
� The SRS is used for uplink channel estimation and uplink
timing. Power control for the SRS improves the precision in
uplink channel estimation and uplink timing.
� The SRS power is calculated using the following formula:
)}()log(10,min{)( _0_CMAX ifPLPPMPiP PUSCHOFFSETSRSSRSSRS +⋅+++= α
The same as PUSCH Power Control
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