huawei wcdma power control & parameters

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WCDMA Power Control and Relevant Parameters N-0

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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




Contents

1. Power Control Overview

2. Open Loop Power Control

3. Closed Loop Power Control




Contents







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

� CDMA system have the embedded characteristics of self-interference, for uplink one

user’s transmission power become interference to others.

� The more connected users, the higher interference. Generally the capacity is limited by

interference level.

� WCDMA suffer from Near-far effect, which means if all UE use the same transmission

power, the one close to the NodeB may block the entire cell.

� Uplink power control can guarantee the service quality and minimize the required

transmission power. It will resolve the near-far effect and resist fading of signal

propagation. By lowering the uplink interference level, the system capacity will be

increased.




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

� The downlink has different characteristics from the uplink, for downlink interference is

caused by multi-path, part of one user’s power also become interference to others.

� Downlink power from adjacent cells also is one part of interference to the own cell.

� Transmission power of NodeB is shared by all users channels, so downlink capacity

usually is considered to be limited by transmission power.

� Downlink power control also can guarantee the service quality and minimize the

required transmission power, so the capacity is maximized in case that interference is

lowered.




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

� Because of channel fading in mobile communication system, the radio signal is

deteriorated and fluctuated, the fast power control become one key technology to resist

this phenomenon.

� In this figure, the channel fading is compensated by the transmitting power, which is

adjusted by the fast power control, so the receiving power is almost constant and the

radio propagation condition is improved.




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

� In WCDMA system, power control includes open loop and closed loop power control.

� Open loop power control is used to determine the initial transmission power, and the

closed loop power control adjusts the transmission power dynamically and

continuously during the connection.

� For uplink, the UE’s transmission power is adjusted; and for downlink, the NodeB’s

transmission power is adjusted.




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

� Open loop power control is used in two cases:

� 1. to decide the initial transmission power of PRACH preamble.

� 2. to decide the initial transmission power of DPCCH / DPDCH.

� Closed loop power control is only applied on DPCCH and DPDCH

� For other common channels, power control is not applied, they will use fixed

transmission power:

� The PCPICH power is defined by the PCPICH TRANSMIT POWER parameter

as an absolute value in dBm.

� All other common channels power is defined in relation with the PCPICH

TRANSMIT POWER parameter, and measured in dB.




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


� MAXTXPOWER

� Parameter name: Max transmit power of cell

� Value Range: 0 to 500

� Physical Value Range: 0dBm to 50 dBm, step 0.1dB


� Content: The sum of the maximum transmit power of all DL channels in a cell.

� Set this parameter through ADD CELLSETUP, query it through LST CELL and modify it

through MOD CELL

� PCPICHPOWER

� Parameter name: PCPICH transmit power

� Value Range: -100 to 500

� Physical Value Range: -10dBm to 50 dBm, step 0.1dB


� Content: This parameter should be set based on the actual environment and the

downlink coverage should be guaranteed firstly. If PCPICH transmit power is configured

too great, the cell capacity will be decreased, for power resources is occupied by

common channel and the interference to traffic channels is also increased.

� Set this parameter through ADD PCPICH, query it through LST PCPICH and modify it

through MOD CELL





� PSCHPOWER or SSCHPOWER

� Parameter name: PSCH / SCCH transmit power

� The recommended value is -50, namely -5dB

� BCHPOWER

� Parameter name: BCH transmit power


� PSCHPOWER or SSCHPOWER

� Parameter name: PSCH / SCCH transmit power

� Value range: -350 to 150.

� Physical value range: -35 to 15, step 0.1dB


� Content: The offset between the PSCH / SSCH transmit power and PCPICH transmit

power.

� For PSCH Power, set it through ADD PSCH, and query it through LST PSCH; for SSCH

Power, set it through ADD SSCH, and query it through LST SSCH. And modify it through

MOD CELL

� BCHPOWER

� Parameter name: BCH transmit power

� Value Range：-350 to 150

� Physical Value Range：-35 to 15 dB, step 0.1dB


� Content: The offset between the BCH transmit power and PCPICH transmit power.

� Set this parameter through ADD BCH, query it through LST BCH, and modify it through

MOD CELL





� MAXFACHPOWER

� Parameter name: Max transmit power of FACH

� The recommended value is 10, namely 1dB

� PCHPOWER

� Parameter name: PCH transmit power


� MAXFACHPOWER

� Parameter name: Max transmit power of FACH

� Value range : -350 to 150



� Content: The offset between the FACH transmit power and PCPICH transmit power.

� Set this parameter through ADD FACH, query it through LST FACH, and modify it through MOD SCCPCH

� PCHPOWER

� Parameter name: PCH transmit power




� Content: The offset between the PCH transmit power and PCPICH transmit power.

� Set this parameter through ADD PCH, query it through LST PCH, and modify it through MOD SCCPCH





� AICHPOWEROFFSET

� Parameter name: AICH power offset

� The default value of this parameter is -6, namely -6dB

� PICHPOWEROFFSET

� Parameter name: PICH power offset


� AICHPOWEROFFSET

� Parameter name: AICH power offset

� Value Range： -22 to 5

� Physical Value Range： -22 to 5 dB, step 1dB


� Content: The offset between the AICH transmit power and PCPICH transmit power.

� Set this parameter through ADD CHPWROFFSET, query it through LST CHPWROFFSET, and modify it through MOD AICHPWROFFSET

� PICHPOWEROFFSET

� Parameter name: PICH power offset


� Physical Value Range：-10 to 5 dB , step 1dB


� Content: The offset between the PICH transmit power and PCPICH transmit power.

� Set this parameter through ADD CHPWROFFSET, query it through LST CHPWROFFSET, and modify it through MOD PICHPWROFFSET




Contents







Contents


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




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.

� In downlink open loop power control, the initial transmission power is calculated

according to the downlink path loss between NodeB and UE.

� In uplink, since the uplink and downlink frequencies of WCDMA are in the same

frequency band, a significant correlation exists between the average path loss of the

two links. This make it possible for each UE to calculate the initial transmission power

required in the uplink based on the downlink path loss.

� However, there is 90MHz frequency interval between uplink and downlink frequencies,

the fading between the uplink and downlink is uncorrelated, so the open loop power

control is not absolutely accurate.




Contents









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

� In access procedure, the first signaling “RRC CONNECTION REQUEST” is

transmitted in message part on PRACH.

� Before PRACH message part transmission, UE will transmit PRACH preamble, and

the transmission power of first preamble is calculated by this 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

� In this formula, where

� PCPICH TRANSMIT POWER defines the PCPICH transmit power in a cell. It is

broadcast in SIB5.

� CPICH_RSCP means received signal code power, the received power

measured on the PCPICH. The measurement is performed by the UE.

� UL interference is the UL RTWP measured by the NodeB. It is broadcast in SIB7.

� CONSTANT VALUE compensates for the RACH processing gain. It is broadcast

in SIB5.

� The initial value of PRACH power is set through open loop power control. UE operation

steps are as follows:

� 1. Read “Primary CPICH DL TX power”, “UL interference” and “Constant value”

from system information.

� 2. Measure the value of CPICH_RSCP;

� 3. Calculate the Preamble_Initial_Power of PRACH.




PRACH Open Loop Power Control Parameters

� CONSTANTVALUE

� Parameter name: Constant value for calculating initial TX

power


� CONSTANTVALUE

� Parameter name: Constant value for calculating initial TX power

� Value range : -35 ~ -10

� Physical Value Range：-35 to -10 dB

� Content: It is used to calculate the transmit power of the first preamble in the

random access process.

� Recommended value: -20

� Set this parameter through ADD PRACHBASIC, query it through LST PRACH,

and modify it through MOD PRACHUUPARAS





� 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.

� After UE transmit the first Preamble on PRACH, it will wait for the corresponding AI

(Acquisition Indicator) on the AICH. The timing relationship of PRACH and AICH is

shown in above figure.

� There will be 3 parameters used to define the timing relationship:

� ττττp-p: time interval between two PRACH preambles. τp-p is not a fixed value, it is

decided by selecting access slot of PRACH preambles,

Here τp-p has one restriction, it must be longer than a minimum value ττττp-p min ,

namely τp-p ≥ τp-p min.

� ττττp-a: time interval between PRACH preamble and AICH Acquisition Indicator. If

UE sends the PRACH preamble, it will detect the responding AI after τp-a time.

� ττττp-m: time interval between PRACH preamble and PRACH message part. If UE

sends the PRACH preamble and receives positive AI from the AICH, it will send

the message part after τp-m time.





� AICHTXTIMING

� Parameter name: AICH transmission timing

� Content:

� When AICHTXTIMING = 0,

ττττp-p,min = 15360 chips, ττττp-a = 7680 chips, ττττp-m = 15360 chips



� The recommended value is 1

� Parameter AICHTXTIMING is used to define the set of τp-p min, τp-a, τp-m.

� AICHTXTIMING

� Parameter name: AICH transmission timing

� Value range：0,1

� Content:





� Recommended value: 1

� Set this parameter through ADD AICH, query it through LST AICH, and modify it

needs de-activated the cell through DEA CELL. After the old configuration of

AICH is deleted through RMV AICH , a new AICH can be established through

ADD AICH





� 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

� After UE transmit the first Preamble,

� If no positive or negative AI on AICH is received after τp-a time,

� UE shall increase the preamble power by POWER RAMP STEP, and retransmit the preamble.

� This ramping process stops until the number of transmitted preambles has

reached the MAX PREAMBLE RETRANSMISSION within an access cycle,

or when the maximum number of access cycles has reached MAX

PREAMBLE LOOP.

� If a negative AI on AICH is received by the UE after τp-a time,

� which indicates rejection of the preamble, the UE shall wait for a certain “Back-off Delay” and re-initiate a new random access process.

� When a positive AI on AICH is received by UE after τp-a time,

� it will transmit the random access message after the uplink access slot of the last preamble.

� The transmit power of the random access message control part should be POWER OFFSET higher than the power of the last transmitted preamble.





� POWERRAMPSTEP

� Parameter name: Power increase step


� PREAMBLERETRANSMAX

� Parameter name: Max preamble retransmission

� The Recommended value is 20

� POWERRAMPSTEP

� Parameter name: Power increase step

� Value range : 1 to 8

� Physical Value Range: 1 to 8 dB

� Content: The power increase step of the random access preambles transmitted

before the UE receives the acquisition indicator in the random access process.




� PREAMBLERETRANSMAX

� Parameter name: Max preamble retransmission


� Content: The maximum number of preambles transmitted in a preamble ramping

cycle.








� 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

� MMAX

� Parameter name: Max preamble loop

� Value range: 1 to 32

� Content: The maximum number of random access preamble loops.


� Set this parameter through ADD RACH, query it through LST RACH, and modify

it first de-activated the cell through DEA CELL, then MOD RACH.

� NB01MIN / NB01MAX

� Parameter name: Random back-off lower / upper limit


� Content: The power offset between the last access preamble and the message

control part. The power of the message control part can be obtained by adding

the offset to the access preamble power.

� The recommended value: 0 for both NB01MIN / NB01MAX

� Set this parameter through ADD RACH, query it through LST RACH, and modify

it first de-activated the cell through DEA CELL, then MOD RACH.





� POWEROFFSETPPM

� Parameter name: Power offset

� The default value:

-3dB for signalling transmission;

-2dB for service transmission.

� POWEROFFSETPPM

� Parameter name: Power offset

� Value range: -5 to 10dB

� Content: The power offset between the last access preamble and the message

control part. The power of the message control part can be obtained by adding

the offset to the access preamble power.

� The recommended value of this parameter is -3dB for signalling transmission ,

and that -2dB for service transmission

� Set this parameter through ADD PRACHTFC, query it through LST PRACH, and

modify it de-activated the cell through DEA CELL . After the old configuration of

PRACH is deleted through RMV PRACHTFC , a new parameters can be

established through ADD PRACHTFC

� The PRACH message also consists of control part and data part, here the POWER

OFFSET is the difference between the PRACH preamble and the message control part.

� The PRACH message uses GAIN FACTOR to set the power of control / data part:

� GAIN FACTOR BETAC ( βc ) is the gain factor for the control part.

� GAIN FACTOR BETAD ( βd ) is the gain factor for the data part.




Contents




2.3 Downlink Dedicated Channel Open Loop Power Cont rol





DL DPDCH Open Loop Power Control


UE Node BServing

RNC

DCH - FP


RRCRRC










DCH - FP

DCH - FP

DCH - FP



� According to the RRC connection establishment procedure, after RNC received the

“RRC CONNECTION REQUEST” message, and NodeB set up the radio link for UE,

then Iub interface resources is established between NodeB and RNC.

� When DCH-FP of Iub interface finished downlink and uplink synchronization, the

downlink DPCH starts to transmit, and DPDCH initial transmission power is calculated

through 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

� In this formula, where

� R is the requested data bitrate by the user

� W is the chip rate

� (Eb/No)DL is the Eb/No target to ensure the service quality. RNC searches for

the (Eb/No)DL dynamically in a set of pre-defined values according to specific cell

environment type, coding type, bitrate, BLER target and etc.

� (Ec/Io)CPICH is the CPICH signal quality measured by UE, then it is sent to RNC

through RACH.

� αααα is the orthogonality factor in the downlink. In Huawei implementation, α is set

to 0.

� Ptotal is the total carrier transmit power measured at the NodeB

� The initial transmission power of downlink DPDCH could be calculated through this

formula, then, initial transmission power of downlink DPCCH can be obtained

according to the power offset: PO1, PO2 and PO3.





Data1 TPC TFCI Data2 Pilot

DownlinkTransmit

Power

DPCCHDPDCH DPDCH DPCCH

PO2PO1

PO3

1 timeslot

� This figure shows the power offset of downlink DPCH :

� PO1 is the power offset of DPCCH TFCI bits to DPDCH data bits.

� PO2 is the power offset of DPCCH TPC bits to DPDCH data bits.

� PO3 is the power offset of DPCCH Pilot bits to DPDCH data bits.

� The values of PO1, PO2 and PO3 are configured on RNC.




DL DPDCH Open Loop Power Control Parameter

� TFCIPO

� Parameter name: TFCI power offset


� TPCPO

� Parameter name: TPC power offset


� TFCIPO

� Parameter name: TFCI power offset


� Physical value range: 0 to 6 dB, step: 0.25

� Content: The offset of TFCI bit transmit power from data bit transmit power in each time slot of radio frames on DL DPCH


� Set this parameter through SET FRC, query it through LST FRC, and modify it through SET FRC

� TPCPO

� Parameter name: TPC power offset



� Content: The offset of TPC bit transmit power from data bit transmit power in each time slot of radio frames on DL DPCH


� Set this parameter through SET FRC, query it through LST FRC, and modify it through SET FRC




DL DPDCH Open Loop Power Control Parameter

� PILOTPO

� Parameter name: Pilot power offset


� PILOTPO

� Parameter name: Pilot power offset



� Content: The offset of pilot bit transmit power from data bit transmit power in

each time slot of radio frames on DL DPCH


� Set this parameter through SET FRC, query it through LST FRC, and modify it

through SET FRC




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.

� Note: Both downlink open loop and close loop power control will be limited by this parameter.

� RLMAXDLPWR

� Parameter name: RL Max DL TX power



� Content: The maximum downlink transmit power of radio link. This parameter should fulfill the coverage requirement of the network planning, and the value is relative to [PCPICH transmit power]

� Set this parameter through ADD CELLRLPWR , query it through LST CELLRLPWR, and modify it through MOD CELLRLPWR

� RLMINDLPWR

� Parameter name: RL Min DL TX power



� Content: The minimum downlink transmit power of radio link. This parameter should consider the maximum downlink transmit power and the dynamic range of power control, and the value is relative to [PCPICH transmit power].

Since the dynamic range of power control is set as 15dB, this parameter is recommended as [RL Max DL TX power] – 15 dB.

� Set this parameter through ADD CELLRLPWR, query it through LST CELLRLPWR, and modify it through MOD CELLRLPWR




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 Power

Service




Contents





2.4 Uplink Dedicated Channel Open Loop Power Contro l




UL DPCCH Open Loop Power Control


UE Node BServing

RNC

DCH - FP


RRCRRC










DCH - FP

DCH - FP

DCH - FP


Open Loop PowerControl of UL DPCCH

� According to the RRC connection establishment procedure, after RNC sent the “RRC

CONNECTION SETUP” message, UE will try to synchronize with NodeB, and the

uplink DPCCH starts to transmit, here DPCCH initial transmission power is calculated

through open loop power control




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 −=

� For Huawei, DPCCH_Power_Offset is calculated with the following formula:

� Where

� PCPICH Transmit Power defines the PCPICH transmit power in a cell.

� UL Interference is the UL RTWP measured by the NodeB.

� Default Constant Value reflects the target Ec/No of the uplink DPCCH

preamble.

Value ttanCons Default

ceInterferen ULPower Transmit PCPICHOffset_Power_DPCCH

++=




UL DPCCH Open Loop Power Control Parameter

� DEFAULTCONSTANTVALUE

� Parameter name: Constant value configured by default

� The recommended value is -27, namely -27dB.

� DEFAULTCONSTANTVALUE

� Parameter name: Constant value configured by default

� Value range : -35 to -10 , unit :dB

� Content: This parameter is used to obtain DPCCH_Power_Offset, which is used

by UE to calculate the initial transmit power of UL DPCCH during the open loop

power control process.

� Recommended value: -27


through SET FRC




Uplink Power Control Restriction

� During the operation of uplink power control, the UE

transmit power shall not exceed the Maximum Allowed

Uplink Transmit Power.

� MAXALLOWEDULTXPOWERFOR(SERVICE)

� Parameter name: Max allowed UE UL TX power

� The recommended value is 24, namely 24 dBm.

� MAXALLOWEDULTXPOWERFOR(CONV, STR, INT, BAC)

� Parameter name: Max allowed UE UL TX power

� Value range: -50 to 33

� Physical value range: -50 to 33 dBm. Step: 1

� Content: The maximum allowed uplink transmit power of a UE in the cell, which

is related to the network planning.


� Set this parameter through ADD CELLCAC, query it through LST CELLCAC,

and modify it through MOD CELLCAC




Contents







Contents


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




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=0 PowerTPC=1 Power

Inner Loop Power Control

� The receiver compares SIRmea (measured SIR) with SIRtar (target SIR), and decide the TPC to

send.

� If SIRmea is greater than SIRtar, the TPC is set as “0” to increase transmission power

� If SIRmea is less than SIRtar, the TPC is set as “1” to decrease transmission power

� TPC is sent to the transmitter in DPCCH, the transmitter will adjust the power according to the

value of received TPC.

� Through inner loop power control, the SIRmea can be ensured to approach SIRtar.


� The receiver compares BLERmea (measured BLER) with BLERtar (target BLER), and decide how

to set the SIRtar.

� If BLERmea is greater than BLERtar, the SIRtar is increased

� If BLERmea is less than BLERtar, the SIRtar is decreased

� The adjusted SIRtar is sent for the inner loop power control, then it will be used in previous

process to guide the transmitter power adjustment.

� Through outer loop power control, the BLERmea can be ensured to approach BLERtar.




Contents









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

� RNC sends SIRtar (target SIR) to NodeB and then NodeB compares SIRmea (measured

SIR) with SIRtar once every timeslot.

� If the estimated SIR is greater than the target SIR, NodeB sends TPC “0” to UE

on downlink DPCCH TPC field.

� Otherwise, NodeB sends TPC “1” to UE.

� After reception of one or more TPC in a slot, UE shall derive a single TPC_cmd (TPC

command, with value among -1,0,1):

� For UE is in soft handover state, more than one TPC is received in a slot, so

firstly multiple TPC_cmd is combined.

� Two algorithms could be used by the UE for deriving the TPC_cmd, those are

PCA1 and PCA2 (PCA means Power Control Algorithm).

� When deriving the combined TPC_cmd, UE shall adjust the transmit power of uplink

DPCCH with a step “UL Closed Loop Power Control Step Size“, as following:

� △DPCCH =△TPC×TPC_cmd

� This adjustment is executed on the DPCCH, then associated DPDCH transmit power

is calculated according to DPDCH / DPCCH power ratio βd / βc.




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

� When UE has single radio link, only one TPC will be received in each slot. In this case,

the value of TPC_cmd shall be derived by PCA1 as follows:

� If the received TPC is equal to 0, then TPC_cmd for that slot is –1.

� If the received TPC is equal to 1, then TPC_cmd for that slot is 1.

� According to DPCCH channel structure, there are 15 time slots in a 10ms radio frame,

and the control is performed once in each time slot, so the frequency of uplink inner

loop PCA1 is 1500Hz.




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

…… ……

� When UE has single radio link, only one TPC will be received in each slot. In this case,

the value of TPC_cmd shall be derived by PCA2 as follows:

� For the first 4 slots of a set, TPC_cmd = 0.

� For the fifth slot of a set, UE make the decisions on as follows:

� If all 5 TPC within a group are 1, then TPC_cmd = 1 in the 5th slot.

� If all 5 TPC within a group are 0, then TPC_cmd = -1 in the 5th slot.

� Otherwise, TPC_cmd = 0 in the 5th slot.

� According to DPCCH channel structure, there are 15 time slots in a 10ms radio frame,

and the control is performed once in each 5-slot group, so the frequency of uplink inner

loop PCA2 is 500Hz.




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.

� On the NodeB side, there are two phases during the soft handover state:

� Uplink synchronization phase

The NodeB should send durative “TPC = 1” to the newly-added RL before

successful synchronization.

� Multi-radio link phase

Each NodeB and each cell will estimate the SIR individually and the general

TPC individually. Therefore, the UE may receive different TPC from different

RLS.

� Especially, when UE is in softer handover state, it means UE has radio links to the

same NodeB, in this case, these RLs (Radio Link) belong to the same RLS (Radio Link

Set), and the all TPCs are the same from each RL.




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)

� When UE is in soft handover state, multiple TPC will be received in each slot from

different cells in the active set. UE will generate the TPC_cmd by PCA1 as follows:

� 1. Combine the TPC from the same RLS and derive the Wi

� When the RLs (Radio Link) are in the same RLS (Radio Link Set), they will

transmit the same TPC in a slot. In this case, the TPCs from the same RLS shall

be combined into one.

� After combination, UE will obtain a soft symbol decision Wi for each RLSi.

� 2. Combine the TPC from different RLSs and derive the TPC_cmd

� UE derives TPC_cmd, it is based on a function γ and all the N soft symbol

decisions Wi:

TPC_cmd = γ (W1, W2, … WN),

Where TPC_cmd can only take the values 1 or -1.

� In Huawei implementation, the function γ shall fulfil the following criteria:

If the TPCs from all RLSs are “1”, the output of γ shall be equal to “1” ;

If one TPC from any RLS is “0”, the output of γ shall be equal to “-1”.





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

� When UE is in soft handover state, multiple TPC will be received in each slot from

different cells in the active set. UE will generate the TPC_cmd by PCA2 as follows:

� 1. Combine the TPC from the same RLS.

� When the RLs are in the same RLS, they will transmit the same TPC in a slot. In

this case, the TPCs from the same RLS shall be combined into one.

� 2. Calculate the TPC_tempi for each RLS

UE derives TPC_tempi through the same way in the last slide, as follows:

� For the first 4 slots of a group, TPC_tempi = 0.

� For the 5th slot of a group:

� If all 5 TPCs within a group are 1, then TPC_tempi = 1 in the 5th slot.

� If all 5 TPCs within a group are 0, then TPC_tempi = -1 in the 5th slot.

� Otherwise, TPC_tempi = 0 in the 5th slot.

� 3. Calculate the TPC_cmd

UE derives TPC_cmd through the following criteria:

� If any TPC_tempi is equal to -1, TPC_cmd is set to -1.

� If , TPC_cmd = 1

� Otherwise, TPC_cmd = 0

5.0temp_TPCN

1 N

1ii >∑

=





RLS3

RLS2

RLS1 100100000000100

100110000011111

111110000011111


…… ……

10ms/frame

Group 1 Group 2 Group 3

RLS3

RLS2

RLS1 00000-1000000000

00000-1000010000

10000-1000010000


…… ……

TPC

TPC_temp i

00000-1000010000

TS14TS13TS12TS11TS10TS9TS8TS7TS6TS5TS4TS3TS2TS1TS0…… ……

TPC_cmd

� The example of the uplink inner loop PCA2 in soft handover state.




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


� PWRCTRLALG

� Parameter name: Power control algorithm selection

� Value range: ALGORITHM1, ALGORITHM2

� Content: This parameter is used to inform the UE of the method for translating

the received TPC commands.

� Recommended value: ALGORITHM1


through SET FRC

� ULTPCSTEPSIZE

� Parameter name: UL closed loop power control step size

� Value range :1dB, 2dB

� Content: The step size of the closed loop power control performed on UL

DPDCH. This parameter is mandatory when the parameter “Power control

algorithm selection” is set as "ALGORITHM1".



through SET FRC




Contents









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

� Basically the downlink inner loop power control process is similar with uplink, UE L3

sends SIRtar to UE L1 and then UE L1 compares SIRmea with SIRtar :

� If the SIRmea is greater than the SIRtar , UE sends TPC “0” to NodeB on uplink

DPCCH TPC field.

� Otherwise, UE sends TPC “1” to NodeB.

� The UE shall check the downlink power control mode before generating the TPC, two

algorithm DPC_MODE1 and DPC_MODE2 could be used by UE to derive the TPC.

Upon receiving the TPC, NodeB shall estimate the transmitted TPC and adjust its

downlink DPCCH/DPDCH power accordingly.

� After reception of one or more TPC in a slot, NodeB shall derive the estimated TPC

TPCest(k) and calculate a PTPC(k), the power adjustment of k:th slot.

� Then NodeB shall adjust the current downlink power P(k-1) to a new power P(k), and

adjust the power of the DPCCH and DPDCH with the same amount, since power

difference between them is fixed.




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.

� The DPC_MODE parameter is a UE specific parameter and controlled by the UTRAN.

� The UE shall check the DPC_MODE (Downlink Power Control Mode) before

generating the TPC, and upon receiving the TPC, the UTRAN shall adjust its downlink

power accordingly.




Downlink Inner Loop Power Control Parameters

� DPCMODE

� Parameter name: Downlink power control mode

� The recommended value is SINGLE_TPC, namely

DPC_MODE = 0

� DPCMODE

� Parameter name: Downlink power control mode

� Value range: SINGLE_TPC (DPC_MODE=0), TPC_TRIPLET_IN_SOFT

(DPC_MODE=1), TPC_AUTO_ADJUST

� Content:

SIGNLE_TPC, a fast power control mode, indicates that a unique TPC

command is sent in each time slot on DPCCH.

TPC_TRIPLET_IN_SOFT, a slow power control mode, indicates that the same

TPC is sent in three time slots, it is applicable to soft handover and it can

decrease the power deviation.

TPC_AUTO_ADJUST, an automatically adjusted mode, indicates that the value

of DPC_MODE can be modified by sending the message “ACTIVE SET

UPDATE” to UE.

� Recommended value: SINGLE_TPC


through SET FRC





� 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 ++−=

� If DOWNLINK_POWER_BALANCE_SWITCH is OFF, then Pbal(k) equals 0.





� PTPC(k) is calculated according to the following:

� If the value of “Limited Power Increase Used” parameter is “Not

Used” , then:

Where

� TPCest (k) is uplink received TPC of the k:th slot

� ∆ ∆ ∆ ∆TPC is downlink power adjustment step size

=−=+

=0)k(TPC if

1)k(TPC if )k(P

estTPC

estTPCTPC ∆

∆





� 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

∆∆∆∆∆∆

Where,

� Power_Raise_Limit : the restriction value of power increasing within a period

� DL_Power_Average_Window_Size : the period of DL transmit power increasing.

� From the definition above, ∆ ∆ ∆ ∆sum (k) indicates the sum of downlink power adjustment in

the latest DL_Power_Average_Window_Size time slots.





� 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

� INNER_LOOP_DL_LMTED_PWR_INC_SWITCH

� This is one switch in PcSwitch (Power control algorithm switch) parameter.

� Value range：1 (ON) , 0 (OFF)

� Content: When it is checked, limited power increase algorithm is applied in the inner loop power control. limited power increase algorithm means that when the DL transmit power is increased, there is a limit for the step, that is, each increase is limited.

� Recommended value (default value): 0

� Set this parameter through SET CORRMALGOSWITCH, query it through LST CORRMALGOSWITCH, and modify it through SET CORRMALGOSWITCH

� POWERRAISELIMIT

� Parameter name: Power increase limit

� Value range: 0 to 10 dB

� Content: The increase of DL transmit power within DL_Power_Average_Window_Size cannot exceed this parameter value.


� Set this parameter through ADD CELLSETUP, query it through LST CELL, and modify it through MOD CELLSETUP





� 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

� DLPOWERAVERAGEWINDOWSIZE

� Parameter name: DL power average window size

� Value range: 1 to 60 time slots

� Content: UTRAN calculates the increase of DL transmit power within the period defined

via this parameter to determine whether the increase exceeds “Power Raise Limit”. If so,

UTRAN will not increase the power even when it receives the command to raise the

power


� Set this parameter through ADD CELLSETUP, query it through LST CELL ,and modify it

through MOD CELLSETUP

� FDDTPCDLSTEPSIZE

� Parameter name: FDD DL power control step size

� Value range: STEPSIZE_0.5DB, STEPSIZE_1DB, STEPSIZE_1.5DB, STEPSIZE_2DB

� Physical value range: 0.5, 1, 1.5, 2 dB

� Content: The step size of the closed loop power control performed on DL DPCH in

Frequency Division Duplex (FDD) mode.

� Recommended value: STEPSIZE_1DB

� Set this parameter through SET FRC, query it through LST FRC, and modify it through

SET FRC




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

� During soft handover, the UL TPC is demodulated in each RLS, then due to

demodulation errors, the DL transmit power of the each branch in soft handover will

drift separately, which causes loss to the macro-diversity gain.

� The DL Power Balance (DPB) algorithm is introduced to reduce the power drift

between links during the soft handover.




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.

� DOWNLINK_POWER_BALANCE_SWITCH

� This is one switch in PcSwitch (Power control algorithm switch) parameter.


� Content: When it is checked, Downlink Power Balance (DPB) algorithm is applied to RNC. Downlink power drift among different RLs, which is caused by TPC bit error or other reasons, could reduce the gain of soft handover. DPB is mainly used to balance the downlink power of different RLs for an UE in order to achieve the best gain of soft handover.

� Recommended value (default value): 0

� Set this parameter through SET CORRMALGOSWITCH, query it through LST CORRMALGOSWITCH, and modify it through SET CORRMALGOSWITCH

� DPBSTARTTHD / DPBSTOPTHD

� Parameter name: DPB start threshold / DPB stop threshold

� Value range: 0~255

� Physical value range: 0~127.5dB; step: 0.5

� Content: The threshold of start / stop DL power balancing in soft handover. When the difference of the power values of every two paths is greater / smaller than or equal to this threshold in soft handover, the RNC shall start / stop DL power balancing; otherwise, shall not.

� The recommended value is DPB start threshold 8, namely 4dB; DPB stop threshold 4, namely 2dB;

� Set this parameter through SET DPB, query it through LST DPB and modify it through SET DPB




Contents










� Why we need outer loop power control?

SIR

BLER

Different curves correspond to different multi-path environment

� The reason of outer loop power control

� The QoS which NAS provides to CN is BLER, not SIR

� The relationship between inner loop power control and outer loop power control

� SIRtar should be satisfied with the requirement of decoding correctly. But

different multi-path radio environments request different SIR

� Therefore, the outer loop power control can adjust the SIR to get a stable BLER

in the changeable radio environment




Uplink Outer Loop Power Control

NodeB UE

Transmit 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

� Uplink outer-loop power control is performed in the SRNC. The SRNC measures the

received BLER and compares it with the BLERtar. If the BLERmea is greater than the

BLERtar, the SRNC increases the SIRtar; otherwise, the SRNC decreases the SIRtar.





� 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

� According to the formula above,

� SIRtar(n) is the target SIR used for the n:th adjustment period.

� MAX means the maximum value among the total i transmission channels.

� BLERmeas,i (n) is measured for the i:th transmission channel in the n:th

adjustment period.

� BLER tar,i is the target BLER of the i:th transmission channel.

� Step i is the adjustment step of the i:th transmission channel.

� Factor is the adjustment factor.




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.

� OPLC_SWITCH

� This is one switch in PCSWITCH (Power control algorithm switch) parameter.


� Comments: When it is checked, RNC updates the uplink SIR TARGET of RLs

on the NodeB side by Iub DCH FP signals

� Default value: 1

� Set this parameter through SET CORRMALGOSWITCH, query it through LST

CORRMALGOSWITCH, and modify it through SET CORRMALGOSWITCH

� INITSIRTARGET

� Parameter name: Initial SIR target value


� Physical value range: -8.2 to +17.3 dB, step 0.1

� Content: Defining the initial SIR target value of outer loop power control.

� Recommended value: refer to the following table.

� Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it

through LST TYPSRB / LST TYPRAB, and modify it through MOD

TYPSRBOLPC / MOD TYPRABOLPC





� SIRADJUSTPERIOD

� Parameter name: OLPC adjustment period


� SIRADJUSTFACTOR

� Parameter name: SIR adjustment coefficient

� The recommended value is 10, namely 1

� SIRADJUSTPERIOD

� Parameter name: OLPC adjustment period.


� Physical value range: 10 to 1000 ms, step 10

� Comments: Outer loop power control varies with radio environment. A fast changing radio environment leads to a shorter outer loop power control adjustment period, while a slower changing one makes the period longer.

� Default value: 40

� Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it through LST TYPSRB / LST TYPRAB, and modify it through MOD TYPSRBOLPC / MOD TYPRABOLPC

� SIRADJUSTFACTOR

� Parameter name: SIR adjustment coefficient


� Physical value range: 0.1 to 1 , step: 0.1

� Content: It is used to adjust the best OLPC step for different cells when the OLPC algorithm is given.

� Recommended value: 10, namely 1

� Set this parameter through SET OPLC / ADD CELLOLPC, query it through LST OPLC, and modify it through SET OPLC / MOD CELLOLPC





� BLERQUALITY

� Parameter name: Service DCH_BLER target value


� SIRADJUSTSTEP

� Parameter name: SIR adjustment step

� The recommended value is shown in the following table.

� SIRADJUSTSTEP

� Parameter name: SIR adjustment step


� Physical value range: 0 to 10 , step: 0.001dB

� Content: Step of target SIR adjustment in outer loop power control algorithm.

� Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it through LST TYPSRB / LST TYPRAB ,and modify it through MOD TYPSRBOLPC / MOD TYPRABOLPC

� BLERQUALITY

� Parameter name: Service DCH_BLER target value

� Value range: -63 to 0

� Physical value range: 5×10-7 to 1

� Content: This QoS-related parameter is used by CRNC to decide the target SIR value that influences access and power control. Use the formula below to get the integer value of the parameter: 10×Log 10(BLER).

� Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it through LST TYPSRB / LST TYPRAB, and modify it through MOD TYPSRBOLPC / MOD TYPRABOLPC






-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 13.6k

SRB 3.4k

Service

� Where,

� CSD: CS domain Data service

� I/B: Interactive and Background.





� 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.

� Where,

� ∆SIRtar is the adjustment of SIRtar, and ∆SIRtar = SIRtar (n+1) - SIRtar (n)

� ABS( ∆SIRtar ) means absolute value of ∆SIRtar





� MAXSIRSTEPUP / MAXSIRSTEPDN

� Parameter name: Maximum SIR increase / decrease step


� MAXSIRTARGET / MINSIRTARGET

� Parameter name: Maximum / Minimum SIR target


� MAXSIRSTEPUP / MAXSIRSTEPDN

� Parameter name: Maximum SIR increase / decrease step



� Content: Maximum allowed SIR increase/ decrease step within an outer loop power control adjustment period.



� MAXSIRTARGET / MINSIRTARGET

� Parameter name: Maximum / Minimum SIR target


� Physical value range: -8.2 to17.3 dB, step: 0.1

� Content: Define the maximum /minimum SIR target value of outer loop power control algorithm.








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 12.2k

SRB 13.6k

SRB 3.4k

Service

� Where,

� CSD: CS domain Data service

� I/B: Interactive and Background.




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

� The downlink outer loop power control is implemented inside the UE. Therefore, this

algorithm is specified by UE manufacturer.

� Generally, the UE L3 measures the received BLER and compares it with the BLERtar. If

the BLERmea is greater than the BLERtar, the L3 increases the SIRtar and send it to UE

L1; otherwise, the L3 decreases the SIRtar.




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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huawei wcdma power control & parameters

Documents

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