*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netContentsPower Control Overviewopen loop Power Control closed loop Power Control

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.net Purpose of uplink power controlUplink transmission characterSelf-interferenceCapacity is limited by interferenceNear-far effectFading Uplink power controlEnsure uplink quality with minimum transmission powerDecrease interference to other UE, and increase capacitySolve the near-far effectSave UE transmission power

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netDownlink transmission characterInterference among different subscribers since the orthogonality is influenced by transmission environmentInterference from other adjacent cellsDownlink capacity is limited by NodeB transmission power(DL power congestion)Fading Downlink power controlEnsure Downlink quality with minimum transmission powerDecrease interference to other cells, and increase capacitySave NodeB transmission power

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netPower Control ClassificationPower control classificationopen loop power controlclosed loop power controlUplink inner-loop power controlDownlink inner-loop power controlUplink outer-loop power controlDownlink outer-loop power control

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.net Open loop Power Control OverviewPurposeUE estimates the power loss of signals on the propagation path by measuring the downlink channel signals, then calculates the transmission power of the uplink channel

principlePath loss of the uplink channel is related to path loss of the downlink channel

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netDisadvantageThis power control method is not accurate as their 190MHZ between uplink and downlink Application scenariosIn a cell, signal fading caused by fast fading is usually more serious than that caused by propagation lossopen loop power control is applied only at the beginning of connection setup, generally in setting the initial power value Open loop Power Control Overview

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.net Open loop Power Control OverviewPRACH open loop power controlDPCCH open loop power control

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netOpen loop Power Control of PRACH

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netOpen loop Power Control of PRACHThe initial value of PRACH power is set through open loop power controlPreamble_Initial_Power = PCPICH DL TX power - CPICH_RSCP + UL interference + Constant Value

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.net

NO.ParameterParameter meaning1Power Offset Pp-m The power offset of the last access preamble and message control part. This value plus the access preamble power is the power of the control part 2Constant Value This parameter is the correction constant used for the UE to estimate the initial transmission power of PRACH according to the open loop power 3PRACH Power Ramp Step This parameter is the ramp step of the preamble power when the UE has not received the capture indication from NodeB 4Preamble Retrans Max This parameter is the permitted maximum preamble repeat times of the UE within a preamble ramp cycle

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netopen loop power control overviewThe characteristics of open loop power controlThe results from open loop power control are not accurate enoughopen loop power control can only decide the initial powerThe advantages of open loop power controlGuarantee the QoSDecrease the interferenceIncrease the system capacity

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netClosed loop power control overviewInner loopOuter loopBLERmea>BLERtarSIRtar

BLERmeaSIRtarTPC=0

SIRmea

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netDownlink closed loop power controlPage*

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netDownlink Inner loop power controlNodeBSet SIRtarTransmit TPC in each TSMeasure SIR and compare it with SIRtarAdjust Tx power with 0.5, 1, 1 or 2dB1500HzL3

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netUplink outer loop power controlNodeBUETransmit TPCMeasure and compare SIRInner-loopSet SIRtarOut loopRNCMeasure received data and compare BLER in the TrCHSet BLERtar10-100Hz

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netUplink-inner loop power controlTPC Decision(01)TPC_CMD-1, 0, 1Adjust DPCCH TxDPCCH=tpcTPC_cmdPCA1 PCA2Adjust DPDCH Tx(c,d)Compare SIRmeas with SIRtarSIRmea>SIRtarTPC=0SIRmea

*Confidential Information of Brilliance Tech. No Spreading without Permission. Security Level: Internal www.brilliancetech.netDownlink outer loop power control

Thank Youwww.brillaincetech.net

*******The random access procedure of PRACH is shown in above figure: UE transmits a preamble using the selected uplink access slot, signature, and preamble transmission power. After that ,UTARN will response AI if the preamble is received. Then the UE will transmit the message part if the AI is received. But, if UE does not receive the AI from UTRAN in p-p period, a next preamble will be transmitted. The process wont stop until the AI is received by UE or the maximum preamble retransmission number or the maximum transmission power is reached.

*Parameters explanation :The values of PCPICH DL TX power, UL interference and Constant value are given in system information.The value of CPICH_RSCP is measured by UE.PCPICH DL TX power is very related to the downlink coverage ability, which is already given in cell setup.UL interference can be measured by NodeB, then broadcasted in system information.Constant Value is the threshold of preamble message. This value has to be analysed very carefully.

The initial value of PRACH power is set through outer loop power control. UE operation steps are as follows:(1) Read IE Primary CPICH DL TX power , UL interference and Constant value from system information .(2) Measure the value of CPICH_RSCP;*****Firstly, UE should estimate the downlink DPDCH/DPCCH power and the SIR, then UE can generate TPC by comparing the estimated SIR to target SIR:If the estimated SIR is greater than the target SIR, TPC is 0 (decrease power)If the estimated SIR is less than the target one, TPC is 1 (increase power)

*For uplink, the RNC will estimate Bit Error Rate (BER) or Block Error Rate (BLER), and adjust the SIRtar in inner loop power control to accomplish the goal of power control. Since this kind of power control is accomplished through upper layer, it is called outer loop power control. When the measured BLER becomes bad, the RNC will increase the SIRtar to improve the quality of received signals; on the other hand, if the measured BLER is too good, the RNC will decrease the SIRtar.

**For downlink, the upper layer of UE will estimate BER or BLER, and adjust the SIRtar in inner loop power control to accomplish the goal of power control. When the measured BLER becomes bad, the upper layer of UE will increase the SIRtar to improve the quality of received signals; on the other hand, if the measured BLER is too good, the upper layer of UE will decrease the SIRtar.

**