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www.huawei.com
Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
WCDMA Power Control and
Relevant Parameters
Page1Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Objectives
� Upon completion of this course, you will be able to:
� Describe the purpose and function of power control
� Explain open loop power control and parameters
� Explain inner loop power control and relevant parameters
� Explain outer loop power control and relevant parameters
Page2Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Power Control Overview
2. Open Loop Power Control
3. Closed Loop Power Control
Page3Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Power Control Overview
2. Open Loop Power Control
3. Closed Loop Power Control
Page4Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Purpose of Uplink Power Control
� Uplink Transmission Character
� Self-interference system
� Uplink capacity is limited by interference level
� Near-far effect
� Fading
� Uplink Power Control Function
� Ensure uplink quality with minimum transmission power
� Decrease interference to other UE, and increase capacity
� Solve the near-far effect
� Save UE transmission power
Page5Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Purpose of Downlink Power Control
� Downlink Transmission Character
� Interference among different subscribers
� Interference from other adjacent cells
� Downlink capacity is limited by NodeB transmission power
� Fading
� Downlink Power Control Function
� Ensure downlink quality with minimum transmission power
� Decrease interference to other cells, and increase capacity
� Save NodeB transmission power
Page6Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Effect of Power Control
Time (ms)0 200 400 600 800
-20
-15
-10
-5
0
5
10
15
20
Rel
ativ
e po
wer
(dB
)Channel Fading
Transmitting power
Receiving power
Page7Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Power Control Classification
� Open Loop Power Control
� Uplink / Downlink Open Loop Power Control
� Closed Loop Power Control
� Uplink / Downlink Inner Loop Power Control
� Uplink / Downlink Outer Loop Power Control
Page8Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Power Control For Physical Channels
� Power control methods are adopted for these physical channels:
� “√" – can be applied, “×" – not applied
√√√√×××SCH
√√√√×××PICH
√√√√×××AICH
×××√√√√PRACH
√√√√×××SCCPCH
√√√√×××PCCPCH
×√√√√√√√√√√√√DPCCH
×√√√√√√√√√√√√DPDCH
Outer Loop
Power Control
Inner Loop
Power Control
No Power
Control
Closed Loop Power ControlOpen Loop
Power
Control
Physical
Channel
Page9Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Common Physical Channel Power Parameters
� MAXTXPOWER
� Parameter name: Max transmit power of cell
� The recommended value is 430, namely 43dBm
� PCPICHPOWER
� Parameter name: PCPICH transmit power
� The recommended value is 330, namely 33dBm
Page10Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Common Physical Channel Power Parameters
� PSCHPOWER or SSCHPOWER
� Parameter name: PSCH / SCCH transmit power
� The recommended value is -50, namely -5dB
� BCHPOWER
� Parameter name: BCH transmit power
� The recommended value is -20, namely -2dB
Page11Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Common Physical Channel Power Parameters
� MAXFACHPOWER
� Parameter name: Max transmit power of FACH
� The recommended value is 10, namely 1dB
� PCHPOWER
� Parameter name: PCH transmit power
� The recommended value is -20, namely -2dB
Page12Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Common Physical Channel Power Parameters
� AICHPOWEROFFSET
� Parameter name: AICH power offset
� The default value of this parameter is -6, namely -6dB
� PICHPOWEROFFSET
� Parameter name: PICH power offset
� The default value of this parameter is -7, namely -7dB
Page13Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Power Control Overview
2. Open Loop Power Control
3. Closed Loop Power Control
Page14Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
2. Open Loop Power Control
2.1 Open Loop Power Control Overview
2.2 PRACH Open Loop Power Control
2.3 Downlink Dedicated Channel Open Loop Power Control
2.4 Uplink Dedicated Channel Open Loop Power Control
Page15Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Open Loop Power Control Overview
� Purpose
� Calculate the initial transmission power of uplink / downlink channels
� Principle
� Estimates the downlink signal power loss on propagation path
� Path loss of the uplink channel is related to the downlink channel
� Application
� Open loop power control is applied only at the beginning of connection
setup to set the initial power value.
Page16Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
2. Open Loop Power Control
2.1 Open Loop Power Control Overview
2.2 PRACH Open Loop Power Control
2.3 Downlink Dedicated Channel Open Loop Power Control
2.4 Uplink Dedicated Channel Open Loop Power Control
Page17Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control
5. Downlink Synchronization
UE Node BServing
RNC
DCH - FP
Allocate RNTISelect L1 and L2parameters
RRCRRC
NBAPNBAP3. Radio Link Setup Response
NBAPNBAP2. Radio Link Setup Request
RRCRRC7. CCCH: RRC Connection Set up
Start RX description
Start TX description
4. ALCAP Iub Data Transport Bearer Setup
RRCRRC9. DCCH: RRC Connection Setup Complete
6. Uplink Synchronization
NBAPNBAP8. Radio Link Restore Indication
DCH - FP
DCH - FP
DCH - FP
Open loop powercontrol of PRACH
1. CCCH: RRC Connection Request
Page18Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control
� Initial Power Calculation for the First Preamble
� When UE needs to set up a RRC connection, the initial power of
uplink PRACH can be calculated according to the following
formula:
Power Tx Initial gCalculatin For Value Constant+ceInterferen UL+
CPICH_RSCP-Power Transmit PCPICH=ernitial_PowPreamble_I
Page19Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control Parameters
� CONSTANTVALUE
� Parameter name: Constant value for calculating initial TX power
� The recommended value is -20, namely -20dB
Page20Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control
� Timing relationship of PRACH and AICH
AICH
PRACH
1 access slot
ττττ p-a
ττττ p-mττττ p-p
Pre-amble
Pre-amble
Message part
Acq. Ind.
Page21Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control Parameters
� AICHTXTIMING
� Parameter name: AICH transmission timing
� Content:
� When AICHTXTIMING = 0,
ττττpppp----p,minp,minp,minp,min = 15360 chips, ττττpppp----aaaa = 7680 chips, ττττpppp----mmmm = 15360 chips
� When AICHTXTIMING = 1,
ττττpppp----p,minp,minp,minp,min = 20480 chips, ττττpppp----aaaa = 12800 chips, ττττpppp----mmmm = 20480 chips
� The recommended value is 1
Page22Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control
� Power Ramping for Preamble Retransmission
Power Ramp Step
Power Offset P p-m
Preamble_Initial_Power
Message part
Pre-amblePre-
amble……
Pre-amblePre-
amble
####1 ####3 ####N####2
Page23Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control Parameters
� POWERRAMPSTEP
� Parameter name: Power increase step
� The recommended value is 2, namely 2dB
� PREAMBLERETRANSMAX
� Parameter name: Max preamble retransmission
� The Recommended value is 20
Page24Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control Parameters
� MMAX
� Parameter name: Max preamble loop
� The recommended value is 8
� NB01MIN / NB01MAX
� Parameter name: Random back-off lower / upper limit
� The recommended value: 0 for both NB01MIN / NB01MAX
Page25Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
PRACH Open Loop Power Control Parameters
� POWEROFFSETPPM
� Parameter name: Power offset
� The default value:
-3dB for signalling transmission;
-2dB for service transmission.
Page26Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
2. Open Loop Power Control
2.1 Open Loop Power Control Overview
2.2 PRACH Open Loop Power Control
2.3 Downlink Dedicated Channel Open Loop Power Control
2.4 Uplink Dedicated Channel Open Loop Power Control
Page27Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
DL DPDCH Open Loop Power Control
5. Downlink Synchronization
UE Node BServing
RNC
DCH - FP
Allocate RNTISelect L1 and L2parameters
RRCRRC
NBAPNBAP3. Radio Link Setup Response
NBAPNBAP2. Radio Link Setup Request
RRCRRC7. CCCH: RRC Connection Set up
Start RX description
Start TX description
4. ALCAP Iub Data Transport Bearer Setup
RRCRRC9. DCCH: RRC Connection Setup Complete
6. Uplink Synchronization
NBAPNBAP8. Radio Link Restore Indication
DCH - FP
DCH - FP
DCH - FP
1. CCCH: RRC Connection Request
DL DPDCH Open Loop Power Control
Page28Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
DL DPDCH Open Loop Power Control
� When a dedicated channel is set up, the initial power of
downlink DPDCH can be calculated according to the following
formula:
−××= Total
CPICH
CPICHDLInitial P
)No/Ec(
P)
No
Eb(
W
RP α
Page29Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
DL DPDCH Open Loop Power Control
Data1 TPC TFCI Data2 Pilot
DownlinkTransmit
Power
DPCCHDPDCH DPDCH DPCCH
PO2PO1
PO3
1 timeslot
Page30Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
DL DPDCH Open Loop Power Control Parameter
� TFCIPO
� Parameter name: TFCI power offset
� The recommended value is 0, namely 0dB
� TPCPO
� Parameter name: TPC power offset
� The recommended value is 12, namely 3dB
Page31Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
DL DPDCH Open Loop Power Control Parameter
� PILOTPO
� Parameter name: Pilot power offset
� The recommended value is 12, namely 3dB
Page32Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Power Control Restriction
� The power of downlink dedicated channel is limited by an
upper and lower limit for each radio link.
� The DL DPDCH power could not exceed Maximum_DL_Power, nor
could it be below Minimum_DL_Power.
� RLMAXDLPWR / RLMINDLPWR
� Parameter name: RL Max / Min DL TX power
� The recommended value is shown in the following table.
Page33Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Power Restriction Parameters
� Referential configurations for typical services:
8-114384 kbps
8-132256 kbps
16-150144 kbps
32-17-264 kbps
64-19-432 kbps
128-23-88 kbps
PS Domain
32-15064 kbps
32-15056 kbps
64-17-232 kbps
64-17-228 kbps
128-18-312.2 kbps AMR
CS Domain
Downlink SFRL Min Downlink
Transmit Power
RL Max Downlink
Transmit PowerService
Page34Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
2. Open Loop Power Control
2.1 Open Loop Power Control Overview
2.2 PRACH Open Loop Power Control
2.3 Downlink Dedicated Channel Open Loop Power Control
2.4 Uplink Dedicated Channel Open Loop Power Control
Page35Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
UL DPCCH Open Loop Power Control
5. Downlink Synchronization
UE Node BServing
RNC
DCH - FP
Allocate RNTISelect L1 and L2parameters
RRCRRC
NBAPNBAP3. Radio Link Setup Response
NBAPNBAP2. Radio Link Setup Request
RRCRRC7. CCCH: RRC Connection Set up
Start RX description
Start TX description
4. ALCAP Iub Data Transport Bearer Setup
RRCRRC9. DCCH: RRC Connection Setup Complete
6. Uplink Synchronization
NBAPNBAP8. Radio Link Restore Indication
DCH - FP
DCH - FP
DCH - FP
1. CCCH: RRC Connection Request
Open Loop PowerControl of UL DPCCH
Page36Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
UL DPCCH Open Loop Power Control
� The initial power of the uplink DPCCH can be calculated according to the
following formula:
� Where
� CPICH_RSCP means the received signal code power, the received power
measured on the CPICH.
� DPCCH_Power_Offset is provided by RNC to the UE via RRC signaling.
RSCP_CPICHOffset_Power_DPCCHPower_Initial_DPCCH −=
Value Constant DefaultceInterferen ULPower Transmit PCPICHOffsetPowerDPCCH ++=__
Page37Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
UL DPCCH Open Loop Power Control Parameter
� DEFAULTCONSTANTVALUE
� Parameter name: Constant value configured by default
� The recommended value is -27, namely -27dB.
Page38Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Power Control Restriction
� During the operation of uplink power control, the UE transmit
power shall not exceed the Maximum Allowed Uplink Transmit
Power.
� MAXALLOWEDULTXPOWER
� Parameter name: Max allowed UE UL TX power
� The recommended value is 21, namely 21 dBm.
Page39Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Power Control Restriction
� In addition, there are four parameters which correspond to the maximum
allowed transmit power of four classes of services respectively:
� MAXULTXPOWERFORCONV
� Parameter name: Max UL TX power of Conversational service
� MAXULTXPOWERFORSTR
� Parameter name: Max UL TX power of Streaming service
� MAXULTXPOWERFORINT
� Parameter name: Max UL TX power of Interactive service
� MAXULTXPOWERFORBAC
� Parameter name: Max UL TX power of Background service
� The recommended value is 24, namely 24 dBm.
Page40Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
1. Power Control Overview
2. Open Loop Power Control
3. Closed Loop Power Control
Page41Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
3. Closed Loop Power Control
3.1 Closed Loop Power Control Overview
3.2 Uplink Inner Loop Power Control
3.3 Downlink Inner Loop Power Control
3.4 Outer Loop Power Control
Page42Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Closed Loop Power Control Overview
� Why closed loop power control is needed?
� Open loop power control is not accurate enough, it can only
estimate the initial transmission power.
� Closed loop power control can guarantee the QoS with minimum
power. By decreasing the interference, the system capacity will be
increased.
Inner LoopOuter Loop
SIRtar
SIRmea>SIRtar→→→→ TPC=0
SIRmea<SIRtar→→→→ TPC=1
UntilSIRmea=SIRtar
TPCBLER tar
BLERmea>BLER tar→→→→SIRtar
BLERmea<BLER tar→→→→SIRtar
Until BLERmea=BLER tar
TPC=1 PowerTPC=0 Power
Page43Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
3. Closed Loop Power Control
3.1 Closed Loop Power Control Overview
3.2 Uplink Inner Loop Power Control
3.3 Downlink Inner Loop Power Control
3.4 Outer Loop Power Control
Page44Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Inner Loop Power Control
� NodeB compares the measured SIR to the preset target SIR, then derives TPC
and sends the TPC Decision to UE.
TPC Decision( 0, 1 )
Generate TPC_cmd( -1, 0, 1 )
Adjust DPCCH Tx△△△△DPCCH =△△△△TPC××××TPC_cmd
Single RL / Soft HOPCA1 / PCA2
Adjust DPDCH Tx( ββββc , ββββd )
NodeB UETransmit TPC
Inner Loop
Set SIRtar
Compare SIRmea with SIRtarSIRmea >>>> SIRtar →→→→ TPC = 0SIRmea ≤≤≤≤ SIRtar →→→→ TPC = 1
Page45Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Inner Loop PCA1 with Single Radio Link
� For single radio link and PCA1, UE derives one TPC_cmd in each time
slot as follows:
0110110110…… ……
…… ……TPC_cmd
TPC
-111-111-111-1
This control is performed in each time slot, so the power control frequency is 1500Hz
Page46Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Inner Loop PCA2 with Single Radio Link
� For single radio link and PCA2, UE derives one TPC_cmd in each 5-slot
group as follows:
This control is performed in each 5-slot group, so the power control frequency is 300Hz
110111111100000
TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS0
10ms radio frame
Group 2Group 1 Group 3
…… ……
0000010000-10000
TPC
TPC_cmd
…… ……
Page47Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Inner Loop with Soft Handover
� When UE enters soft handover state, on the NodeB side, there
are two phases :
� Uplink synchronization phase
� Multi-radio link phase
� On UE side, UE will receive different TPCs from different RLS in
one time slot. Therefore, the UE should combine all the TPCs to
get a unique TPC_CMD.
Page48Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Inner Loop PCA1 with Soft Handover
For each slot, combine TPC from the same RLS, then get Wi
CELL1 CELL2
CELL4CELL3
RL1-1 RL1-2
RLS1
RLS2 RLS3Get TPC_cmd based onTPC_cmd = γγγγ (W1, W2, … WN)
0110110110…… ……RLS1-TPC (W1)
…… ……RLS2-TPC (W2) 1010101101
…… ……
…… ……TPC_cmd
1101100100
-1-1-1-11-1-11-1-1
RLS3-TPC (W3)
Page49Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Inner Loop PCA2 with Soft Handover
Combine TPC from same RLSin each time slot
Calculate TPC_cmd� If any TPC_tempi = -1 , TPC_cmd = -1
� If , TPC_cmd = 1
� Otherwise, TPC_cmd = 0
Calculate TPC_temp i for each RLS i
5.0_1
1
>∑=
N
iitempTPC
N
CELL1 CELL2
CELL4CELL3
RL1-1 RL1-2RLS1
RLS2 RLS3
Page50Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Inner Loop PCA2 with Soft Handover
RLS3
RLS2
RLS1 100100000000100
100110000011111
111110000011111
TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS0
…… ……
10ms/frame
Group 1 Group 2 Group 3
RLS3
RLS2
RLS1 00000-1000000000
00000-1000010000
10000-1000010000
TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS0
…… ……
TPC
TPC_temp i
00000-1000010000
TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS0…… ……
TPC_cmd
Page51Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Inner Loop Power Control Parameters
� PWRCTRLALG
� Parameter name: Power control algorithm selection
� The recommended value is ALGORITHM1
� ULTPCSTEPSIZE
� Parameter name: UL closed loop power control step size
� The recommended value is 1, namely 1dB
Page52Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
3. Closed Loop Power Control
3.1 Closed Loop Power Control Overview
3.2 Uplink Inner Loop Power Control
3.3 Downlink Inner Loop Power Control
3.4 Outer Loop Power Control
Page53Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Inner Loop Power Control
� UE L1 compares the measured SIR to the preset target SIR, then derives TPC
and sends the TPC Decision to NodeB.
Derive TPCest(k)( 0, 1 )
Generate PTPC(k)
Calculate P(k)
Adjust DPCH Tx Power
DPC_MODE
NodeB
L3 Set SIRtar
Derive and transmit TPC based on DPC_MODE
Inner Loop
UE
L1 compare SIRmea with
SIRtar
Page54Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Inner Loop Power Control Mode
� Two DPC_MODE (Downlink Power Control Mode) could be used:
� If DPC_MODE = 0, UE sends a unique TPC in each slot, UTRAN shall
derive TPCest to be 0 or 1, and update the power every slot;
� If DPC_MODE = 1, UE repeats the same TPC over 3 slots, UTRAN
shall derive TPCest over three slots to be 0 or 1, and update the
power every three slots.
Page55Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Inner Loop Power Control Parameters
� DPCMODE
� Parameter name: Downlink power control mode
� The recommended value is SINGLE_TPC, namely DPC_MODE = 0
Page56Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Inner Loop Power Control
� After estimating the TPC, the UTRAN shall set the downlink power to
P(k) for k:th slot according to the following formula:
Where
� P(k-1) is downlink transmission power in (k-1):th slot
� PTPC(k) is the adjustment of downlink power in k:th slot
� Pbal (k) is correction value according to the downlink power balance
procedure. For a single radio link, Pbal (k) equals 0.
)k(P)k(P)1k(P)k(P balTPC ++−=
Page57Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Inner Loop Power Control
� PTPC(k) is calculated according to the following:
� If the value of “Limited Power Increase Used” parameter is “Not
Used” , then:
Where
� TPCTPCTPCTPCest est est est (k)(k)(k)(k) is uplink received TPC of the k:th slot
� ∆ ∆ ∆ ∆TPCTPCTPCTPC is downlink power adjustment step size
=−=+
=0)k(TPC if
1)k(TPC if )k(P
estTPC
estTPCTPC ∆
∆
Page58Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Inner Loop Power Control
� If the value of “Limited Power Increase Used” parameter is
“Used” , then:
Where ∑−
−=
=1k
Size_Window_Average_Power_DLkiTPCsum )i(P)k(∆
=−≥+=<+=+
=0)k(TPC if
Limit_Raise_Power)k( and 1)k(TPC if 0
Limit_Raise_Power)k( and 1)k(TPC if
)k(P
estTPC
TPCsumest
TPCsumestTPC
TPC
∆∆∆∆∆∆
Page59Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Inner Loop Power Control Parameters
� INNER_LOOP_DL_LMTED_PWR_INC_SWITCH
� This is one switch in PCSWITCH (Power control algorithm switch)
parameter.
� The default value is 0, namely OFF.
� POWERRAISELIMIT
� Parameter name: Power increase limit
� The recommended value is 10dB
Page60Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Inner Loop Power Control Parameters
� DLPOWERAVERAGEWINDOWSIZE
� Parameter name: DL power average window size
� The recommended value is 20 time slots
� FDDTPCDLSTEPSIZE
� Parameter name: FDD DL power control step size
� The recommended value is STEPSIZE_1DB, namely 1dB
Page61Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Power Balance
� Purpose
� The purpose of this procedure is to
balance the DL transmission powers of
more than one Radio Links.
� The start and stop of DPB
� The power offset of two RLs is greater
than the DPB start threshold, the DPB
process is started
� The power offset of two RLs is less than
the DPB stop threshold, the DPB process
is stopped
NodeB NodeB
Monitor the Tx power of NodeBs and start the DPB
process
DPB process
Page62Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Power Balance Parameters
� DOWNLINK_POWER_BALANCE_SWITCH
� This is one switch in PCSWITCH (Power control algorithm switch)
parameter.
� The default value is 0, namely OFF.
� DPBSTARTTHD / DPBSTOPTHD
� Parameter name: DPB start threshold / DPB stop threshold
� The recommended value:
DPB start threshold 8, namely 4dB;
DPB stop threshold 4, namely 2dB.
Page63Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Contents
3. Closed Loop Power Control
3.1 Closed Loop Power Control Overview
3.2 Uplink Inner Loop Power Control
3.3 Downlink Inner Loop Power Control
3.4 Outer Loop Power Control
Page64Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Outer Loop Power Control
� Why we need outer loop power control?
SIR
BLER
Different curves correspond to different multi-path environment
Page65Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Outer Loop Power Control
NodeB UETransmit TPC
Measure SIR and compare with SIRtar
Inner loop
Set SIRtar
Out loop
RNC
Measure BLER of received data and compare with the BLERtar
Set BLERtar
Page66Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Outer Loop Power Control
� SIRtar Adjustment
Where
� i is the i:th transmission channel.
� n is the n:th adjustment period.
××
−−+−= FactorStep
BLER
BLER)1n(BLER)1n(SIRMAX)n(SIR i
i,tar
i,tari,meastartar
Page67Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Outer Loop Power Control Parameters
� OPLC_SWITCH
� This is one switch in PCSWITCH (Power control algorithm switch)
parameter.
� The default value is 1, namely ON
� INITSIRTARGET
� Parameter name: Initial SIR target value
� The recommended value is shown in following table.
Page68Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Outer Loop Power Control Parameters
� SIRADJUSTPERIOD
� Parameter name: OLPC adjustment period
� The recommended value is shown in following table.
� SIRADJUSTFACTOR
� Parameter name: SIR adjustment coefficient
� The recommended value is 10, namely 1
Page69Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Outer Loop Power Control Parameters
� BLERQUALITY
� Parameter name: Service DCH_BLER target value
� The recommended value is shown in following table.
� SIRADJUSTSTEP
� Parameter name: SIR adjustment step
� The recommended value is shown in the following table.
Page70Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Outer Loop Power Control Parameters
� Referential configurations for typical services:
-20-20-20-20-20-20-20-20-27-20-20-20Service
DCH_BLER
target value
142122107102102102102102122102122102SIR init
target value
4444444425104SIR
adjustment
step
222222242224OLPC
adjustment
period
PS I/B
384k
PS I/B
256k
PS I/B
144k
PS I/B
128k
PS I/B
64k
PS I/B
32k
PS I/B
16k
PS I/B
8k
CSD
64k
AMR
12.2k
SRB
13.6
k
SRB
3.4kService
Page71Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Outer Loop Power Control
� The parameters MaxSirStepUp and MaxSirStepDown limit the
adjustment range of the SIRtar , and the algorithm is:
� If ∆SIRtar > 0 and ∆SIRtar > “MaxSirStepUp” ,
then SIRtar (n+1) = SIRtar (n) + MaxSirStepUp
� If ∆SIRtar < 0 and ABS( ∆SIRtar ) > “MaxSirStepDown” ,
then SIRtar (n+1) = SIRtar (n) – MaxSirStepDown
� The parameters MaxSirtarget and MinSirtarget limit the range of the
SIRtar at any time.
Page72Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Outer Loop Power Control Parameters
� MAXSIRSTEPUP / MAXSIRSTEPDN
� Parameter name: Maximum SIR increase / decrease step
� The recommended value is shown in following table.
� MAXSIRTARGET / MINSIRTARGET
� Parameter name: Maximum / Minimum SIR target
� The recommended value is shown in following table.
Page73Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Uplink Outer Loop Power Control Parameters
� Referential configurations for typical services:
4004004004004004004004001000500500400Maximum SIR
increase step
200200200200200200200200100200200200Maximum
SIR decrease step
626262626262626262626262Minimum SIR
target
172152137132132132132132152132132132Maximum SIR
target
PS I/B
384k
PS I/B
256k
PS I/B
144k
PS I/B
128k
PS I/B
64k
PS I/B
32k
PS I/B
16k
PS I/B
8k
CSD
64k
AMR
12.2
k
SRB
13.6
k
SRB
3.4kService
Page74Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Downlink Outer Loop Power Control
NodeB
set SIRtar
Transmit TPC
Measure SIR and compare with SIRtar
Measure BLER of received data and compare with the
BLERtar
Outer loop
Inner loop
L1
L3
UE
Page75Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Summary
� In this course, we have discussed function, principle and
common parameters of the following power control algorithm:
� Open loop power control
� Inner loop power control
� Outer loop power control
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