64250639 HSDPA Low Throughput[1]

HSDPA Introduction and Troubleshooting for Low Throughput

Sadok Ben Ali 28 Nov 2008 Ericsson Internal

1

2008-11-28

Key characteristics of HSDPA Scheduled user

high data rate

User 1 User 2

low data rate Time #1 #2 #1#2 #1 #2 #1

Scheduling

Power Total cell power

High data rate

Low data rate

HS-DSCH (rate controlled)

Dedicated channels (power controlled) Common channels

t HS-DSCH with dynamic power allocation

Fast Link Adaptation

Ericsson Internal

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Shared Channel Transmission 

(1)

A set of radio resources dynamically shared among multiple users, primarily in the time domain SF4 SF8 SF16 SF32

Cell CCH(s)

HS-PDSCH

SF64

s-CCP CH (PS32Kbps on FACH)

SF128 HS-SCCH

SF256 p-CCPCH

PICH

p-CPICH



AICH

Up to 15 codes (SF16) can be allocated and shared between the users. It also depends on what the UE can support. Ericsson Internal

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Shared Channel Transmission

(2)

HSDPA channel structure    

DL: High-Speed Downlink Shared Channel – HS-DSCH DL: High-Speed Shared Control Channel(s) – HS-SCCH (SCHEDULING) Associated Dedicated Channel – A-DCH bidirectional DCH for SRB3.4 signaling ( DPCCH+DPDCH) UL :HS Dedicated Physical Common Control Channel - HS-DPCCH (CQI, HARQ ACK/NACK) Iu

Iu

RNC

Iub

Ericsson Internal

Associated Dedicated Channels

4

RNC

Iur

Iub

2008-11-28

Fast Link Adaptation (1)

CQI – Channel Quality Indicator    



UE sends CQI info in the UL to aid rate adaptation and scheduling CQI (1-30) provides the Node B with a measure of the UE's perceived channel quality and the UE receiver performance The CQI report estimates the number of bits that can be transmitted to the UE using a certain assumed power with a block error rate of (blerQualityTargetDl =1%) UE assumes a HS- PDSCH power to calculate CQI : PHS_assumed = RSCPCPICH + hsMeasurementPowerOffset +  (3GPP 25214) CQI = 0 if SNR >> DL)

384000 }, (>>> UL)} In SGSN, check if the correct QoS profile has been linked to the IMSI series that were used in the test; In GGSN, verify the policing with the PDP context to see if there is any limitation on the downlink. The link between the GGSN and the IP router in the IP backbone has to have enabled the auto-negotiation and fixed 100 Mbit/s speed in full-duplex mod

Ericsson Internal

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HSDPA Throughput Analysis Counters : Aal2PathVccTp

pmBwErrBlocks pmBwLostCells pmBwMissinsCells pmFwErrBlocks pmFwLostCells pmFwMissinsCells pmLostBrCells pmLostFpmCells

HsDschResources

pmAckReceived pmAverageUserRate pmIubMacdPduCellReceivedBits pmNackReceived pmNoActiveSubFrames pmNoInactiveRequiredSubFrames pmReportedCqi pmSumAckedBits pmSumNonEmptyUserBuffers pmSumTransmittedBits pmTransmittedCarrierPowerNonHs pmUsedCqi

IubDataStreams

pmCapAllocIubHsLimitingRatio pmHsDataFramesLost pmHsDataFramesReceived pmIubMacdPduRbsReceivedBits pmTargetHsRate

Ericsson Internal

16

VplTp

pmReceivedAtmCells pmTransmittedAtmCells pmSecondsWithUnexp

VclTp

pmReceivedAtmCells pmTransmittedAtmCells

RncFunction

pmSentPacketDataHs1 (is stepped only if < 1kB) pmSentPacketDataHs2 (is stepped only if < 10kB but > 1kB) pmSentPacketDataHs3 (is stepped only if < 100kB but > 10kB) pmSentPacketDataHs4 (is stepped only if > 100kB). pmTotalPacketDurationHs1 - duration for data < 1kB. pmTotalPacketDurationHs2 - duration for data < 10kB but > 1kB pmTotalPacketDurationHs3 - duration for data < 100kB but > 10kB pmTotalPacketDurationHs4 - duration for data > 100kB

2008-11-28

HSDPA Throughput Analysis KPIs: RNC : 

HsTputAverg = 8 * 1000 * ( pmSentPacketDataHs1 / 1000 + pmSentPacketDataHs2 / 1000 + pmSentPacketDataHs3 + pmSentPacketDataHs4 ) / ( pmTotalPacketDurationHs1 + pmTotalPacketDurationHs2 + pmTotalPacketDurationHs3 + pmTotalPacketDurationHs4 )



HsTputGt100KbAverg = 8 * 1000 * (pmSentPacketDataHs4) / (pmTotalPacketDurationHs4) HsTputAverg is looking at HS throughput over all data transmission sizes, even if a small amount of data is sent. HsTputGt100KbAverg is for data transmissions > 100kB, the HsTputGt100KbAverg should give a better indication of the performance achieved with HS because you'd be most interested in the speed when performing large downloads rather than when using smaller transmission sizes where you may not be utilizing the full 2ms air interface frame.

RBS :    

The average MAC-hs throughput per PS Interactive HSDPA user: pmSumAckedBits / (TTI * pmSumNonEmptyUserBuffers) The average MAC-hs Data rate per PS Interactive HSDPA user: pmSumTransmittedBits / (TTI * pmSumNonEmptyUserBuffers) The MAC-hs throughput on cell level: pmSumAckedBits / (TTI * pmNoActiveSubFrame) The MAC-hs data rate on cell level: pmSumTransmittedBits / (TTI * pmNoActiveSubFrame)

Ericsson Internal

17

If MAC-hs Data rate mush bigger than MAC-hs throughput per user there is a high NACK subframe, we need to check BLER, R99 used power…

2008-11-28

HSDPA Throughput Analysis IubDataStreams Is to check capacity limitation in the Iub Interface :  pmCapAllocIubHsLimitingRatio : is the relative number of occurrences when the calculated Capacity Allocation figure is limited by the Iub HS bandwidth during a 100 ms period (compared to the total number of 100 ms periods in the PM interval. This is related to Physical throughput, so it will include all the overheads, retransmissions, and the HSDSCH throughput is not mapped to this counter directly. If the counter is pegging, that means the Iub bandwidth limit as been met sometimes, so the configuration of the Iub, i.e., the AtmTrafficDescriptor on AAL2 VC's should be verified.



pmtargetHsRate : is real capacity of the Iub interface is calculated by the Iub Flow Control according to retransmission ratio and MaxHsRate

Transport Network  

VplTp and VclTp counters are used to verify that everything is sent from RNC is received in RBS. Is to check the quality of transport network.

Ericsson Internal

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HSDPA PARAMETRS MO Class ChannelSwitching ChannelSwitching ChannelSwitching Rcs RncFunction RncFunction RncFunction RncFunction RncFunction RncFunction UeMeasControl UeMeasControl MO Class IubDataStream NodeBFunction NodeBFunction

Parameter downswitchThreshold downswitchTimerThreshold hsdschInactivityTimer hsDschRcLostT hsCellChangeAllowed hsOnlyBestCell hsToDchTrigger. servHsChangeInterRnc hsToDchTrigger. servHsChangeIntraRnc hsToDchTrigger. changeOfBestCellIntraRnc hsToDchTrigger. poorQualityDetected hsQualityEstimate hsTimeToTrigger1d Parameter maxHsRate flexibleSchedulerOn supportOf16qam

Ericsson Internal

Value 29 TRUE TRUE

19

(1) According to… E/// Default BaseLine 1.6 BaseLine 1.6 E/// Default BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6

Value 0 1 8 100 1 1 ON ON ON ON 1 1280 According to… BaseLine 1.6, 2 E1s links BaseLine 1.6 BaseLine 1.6

2008-11-28

HSDPA PARAMETRS (2) MO Class Carrier Carrier Carrier HsDsch HsDsch HsDsch HsDsch HsDsch HsDsch HsDsch HsDsch HsDsch RbsLocalCell RbsLocalCell RbsLocalCell UtranCell UtranCell UtranCell

Parameter cqiAdjustmentOn hsScchMaxCodePower queueSelectAlgorithm codeThresholdPdu656 deltaAck1 deltaAck2 deltaCqi2 deltaNack1 deltaNack2 hsMeasurementPowerOffset numHsPdschCodes numHsScchCodes dynamicHsPdschCodeAdditionOn maxNumHsdpaUsers maxNumHsPdschCodes beMarginDlCode dlCodeAdm hsdpaUsersAdm

Ericsson Internal

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Value 1 -20 1 0 5 7 6 5 7 80 5 3 1 16 15 1 85 12

According to… BaseLine 1.6 E/// Default BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 E/// Recommended BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6 BaseLine 1.6

2008-11-28

Ericsson Internal

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