238828694 Lte High Capacity Event Parameters

Lte Lte High High capacity capacity event parameters

Prepared By: RAJESH KUMAR

Focus areas •

LTE High Capacity Focus Areas 1.

Con Control trol Chan Channe nell Dime Dimens nsio ioni ning ng PUCCH Resources

•

PDCCH Resources

2.

UL Noise Rise

3.

PRB PRB Uti Utili lizzatio ation n / Cell Cell Thr Through oughpu putt Cap Capac acit ity y

4.

MP Load •

5. •

•

RRC Connection Setup Intensity  –

Due to UE releases by Inactivity

 –

Due to UE releases by RLC Supervision

•

Incoming Handover Intensity

•

Hardware expansion Conn onnecte cted User sers Lic License ense

Summary of High Capacity Parameter Parameter Settings Settings

Focus areas •

LTE High Capacity Focus Areas 1.

Cont Co ntro roll Ch Chan anne nell Di Dime mens nsio ioni ning ng

PUCCH Resources

•

PDCCH Resources

2.

UL Noise Rise

3.

PRB PRB Uti Utili lizzatio ation n / Cell Cell Thr Through oughpu putt Cap Capac acit ity y

4.

MP Load •

5. •

•

RRC Connection Setup Intensity  –

Due to UE releases by Inactivity

 –

Due to UE releases by RLC Supervision

•

Incoming Handover Intensity

•

Hardware expansion Conn onnecte cted User sers Lic License ense

Summary of High Capacity Parameter Settings

Control channel resources •

UL Control Channel Resources  –

PUCCH •

 –

Focus Area for High

PRACH •

•

nRB,PUCCH depends on number of SR and CQI resources resources Capacity Parameters

nRB,PRACH in 1 radio frame is independent of bandwidth and is fixed for different cell range

DL Control Channel Resources  –

PDCCH •

 –

nRE,PCFICH in 1 radio frame is 160, independent of bandwidth and # of antenna ports

PHICH •

 –

Focus Area for High Capacity Parameters

PCFICH •

 –

nRE,PDCCH depends on CFI

nRE,PHICH in 1 radio frame depends on bandwidth and is fixed for different different bandwidth

PBCH •

nRE,PBCH in 1 radio frame is 240, independent of bandwidth and # of antenna ports

Pucch resources intro

•

•

PUCCH is used for transmitting  –

SR, HARQ ACK/NACK (PUCCH Format 1)

 –

CQI, RI (PUCCH Format 2)

UE is allocated SR and CQI resources during setup procedure, and the resources are kept as long as UE is UL synchronized. synchronized.  –

•

•

UE is not allowed to connect to a cell if there’s no free SR resources

noOfPucchSrUsers and noOfPucchCqiUsers determine number of resources for SR and CQI per cell PUCCH is allocated by  –

2 RB at the band edges (RB-pair)

 –

Time domain sharing, each PUCCH is assigned as signed to

a UE with a periodicity deciding which sub-frame UE can access PUCCH (default periodicity for CQI is 80ms, SR is 10ms) •

Current setting  –

noOfPucchSrUsers, noOfPucchCqiUsers = 320

Pucch resources highest pucch resources for sr &TCQI  = 10ms (SR periodicity) SR

nSF,PUCCH = 10 (# sub-frames s ub-frames for PUCCH) ncap = 4 (CQI resources/RB pair) TCQI = 80ms (CQI periodicity)

•

1st attempt (nRB,format1 = nRB,format2 = 4)

›

3rd attempt (nRB,format1 = 6, nRB,format2 = 2)

nSR,res = (36*4-44)*10*10/10 = 1000 (>810)

nSR,res = (36*6-44)*10*10/10 = 1720 (>810)

nCQI,res = 4*4*80*10/10 = 1280 (>880)

nCQI,res = 2*4*80*10/10 = 640 (810) nCQI,res = 3*4*80*10/10 = 960 (>880)

noOfPucchSrUsers (limited by nCQI.res )=noOfPucchCqiUsers=640 This setting will reduce peak UL throughput

Pucch resources number of pucch rb-pairs

› •

Current setting (noOfPucchSrUsers = noOfPucchCqiUsers = 320)

Recommended setting (noOfPucchSrUsers = noOfPucchCqiUsers = 640)

nPUCCH,SR = [640/10 * 10/10] = 64

nPUCCH,SR = [320/10 * 10/10] = 32

nRB,Format1 = [(64+44)/36] = 3

nRB,Format1 = [(32+44)/36] = 3

nRB,Format2 = [640/(4*80) * 10/10] = 2

nRB,Format2 = [320/(4*80) * 10/10] = 1

nRB,PUCCH = 3 + 2 = 5 (even  6, < max RB pair per DU)

nRB,PUCCH = 3 + 1 = 4

 Odd

number will leave 1 RB-pair unused by PUCCH and PUSCH

Pucch resources observability

•

pmPucchSrCqiResCongCqi  –

•

The number of times a PUCCH allocation request for CQI resource(s) could not be granted granted

pmPucchSrCqiResCongSr  –

The number of times a PUCCH allocation request for SR resource(s) could not be granted

Pdcch resources adaptive pdcch (1/2) •

PDCCH is used for  –

•

•

UL/DL scheduling assignments, e.g. PUSCH/PDSCH resource indication, transport format indication, HARQ info and PUCCH/PUSCH PC commands

Number of OFDM symbols available for PDCCH in a sub-frame is CFI. Max OFDM symbols, limited by pdcchCfiMode, is not exceeded

Recommended Recommended setting:  –

 –

Bandwidth =< 10MHz : CFI_AUTO_MAXIMUM_3 CFI_AUTO_MAXIMUM_3 (current setting), to handle peaks of PDCCH load Bandwidth > 10MHz : CFI_AUTO_MAXIMUM_2, CFI_AUTO_MAXIMUM_2, since higher number of symbols for PDCCH can increase RB pairs for PUCCH, which leads to reduced UL peak rate

Pdcch resources observability •

pmPdcchCceUtil  –

•

PDF of % of CCEs utilized compared with total CCEs available (at the maximum CFI permitted by pdcchCfiMode) each subframe, considering bandwidth and antenna configuration.

pmPdcchCfiUtil  –

PDF of number of subframes each CFI value was assigned

Focus areas •

LTE High Capacity Focus Areas 1.

Con Control trol Chan Channe nell Dime Dimens nsio ioni ning ng PUCCH Resources

•

PDCCH Resources

2.

UL Noise Rise

3.

PRB PRB Uti Utili lizzatio ation n / Cell Cell Thr Through oughpu putt Cap Capac acit ity y

4.

MP Load •

5. •

•

RRC Connection Setup Intensity  –

Due to UE releases by Inactivity

 –

Due to UE releases by RLC Supervision

•

Incoming Handover Intensity

•

Hardware expansion Conn onnecte cted User sers Lic License ense

Summary of High Capacity Parameter Parameter Settings Settings

Ul noise rise pzeronominalpucch, pzeronominalpucch, pzeronominalpusch pzeronominalpusch •

•

pZeroNominalPucch and pZeroNominalPusch can be used to adjust power control target, trade off between coverage and capacity Current setting  –  –

pZeroNominalPucch pZeroNominalPucch = -117dBm pZeroNominalPusch pZeroNominalPusch = -96dBm (should be reduced to default -103dBm -103dBm to reduce UL interference interference peaks at high load)

Ul noise rise observability •

pmSinrPucchDistr  –

•

pmSinrPuschDistr  –

•

The measured Noise and Interference Interference Power on PUCCH, according to 36.214

pmRadioTbsPwrRestricted  –

•

The measured Noise and Interference Interference Power on PUSCH, according to 36.214 of the SINR values calculated for PUSCH

pmRadioRecInterferencePwrPucch  –

•

Distribution of the SINR values calculated for PUSCH

pmRadioRecInterferencePwr  –

•

Distribution of the SINR values calculated for PUCCH

The number of Transport Blocks on MAC level scheduled in uplink where the UE was considered to be power limited.

pmRadioTbsPwrUnrestricted  –

The number of Transport Blocks on MAC level scheduled in uplink where the UE was NOT considered to be power limited.

Focus areas •

LTE High Capacity Focus Areas 1.

Con Control trol Chan Channe nell Dime Dimens nsio ioni ning ng PUCCH Resources

•

PDCCH Resources

2.

UL Noise Rise

3.

PRB PR B Uti Utili liza zati tion on / Cell Cell Th Thro roug ughp hput ut Cap Capac acit ity y

4.

MP Load •

5. •

•

RRC Connection Setup Intensity  –

Due to UE releases by Inactivity

 –

Due to UE releases by RLC Supervision

•

Incoming Handover Intensity

•

Hardware expansion Conn onnecte cted User sers Lic License ense

Summary of High Capacity Parameter Settings

Prb utilization / cell throughput capacity schedulingalgorithm •

System Fairness

Current setting schedulingAlgorithm = 3 (PROPORTIONAL_FAIR_MEDIUM), propose to change to following at high load  –

4 (PROPORTIONAL_FAIR_LOW) or

 –

5 (MAXIMUM_C_OVER_I)



Higher Cell Throughput



Higher TTI utilization



Higher PRB utilization

For PFL or Max C/I, user at cell edge may have low throughput, as scheduler has higher weightage for RF condition

Cell Throughput

•

Performance comparison between different schedulers  –

Best cell throughput (from lowest to highest) •

 –

RR < ER < PFH < PFM < PFL < MCI

System fairness (from lowest to highest) •

MCI < PFL < PFM < PFL < ER < RR

Prb utilization / cell throughput capacity observability •

Average Cell Throughput UL = pmUeThpVolUl/(pmSchedActivityCellUl/1000)

•

Average Cell Throughput DL = pmPdcpVolDlDrb/(pmSchedActivityCellDl/1000)

•

pmPrbUtilUl  –

•

A distribution that shows the uplink Physical Resource Block (PRB) pair utilization (total number of used PRB pairs by available PRB pairs) on the Physical Uplink Shared Channel (PUSCH)

pmPrbUtilDl  –

A distribution that shows the downlink Physical Resource Block (PRB) pair utilization (total number of used PRB pairs by available PRB pairs) on the Physical Downlink Shared Channel (PDSCH)

•

Average # Simultaneous Active UE UL = pmActiveUeUlSum/pmSchedActivityCellUl

•

Average # Simultaneous Active UE DL = pmActiveUeDlSum/pmSchedActivityCellDl

Focus areas •

LTE High Capacity Focus Areas 1.

Con Control trol Chan Channe nell Dime Dimens nsio ioni ning ng PUCCH Resources

•

PDCCH Resources

2.

UL Noise Rise

3.

PRB PRB Uti Utili lizzatio ation n / Cell Cell Thr Through oughpu putt Cap Capac acit ity y

4.

MP Load •

5. •

•

RRC Connection Setup Intensity  –

Due to UE releases by Inactivity

 –

Due to UE releases by RLC Supervision

•

Incoming Handover Intensity

•

Hardware expansion Conn onnecte cted User sers Lic License ense

Summary of High Capacity Parameter Settings

Mp load mp load control mechanism (new in L13A)

Main contributors contributors (signaling) for MP Load • RRC Connection Setups Incoming Handovers • Paging Requests •

Mp load •

•

•

1.1 RRC Connection setup intensity (due to UE releases by inactivity) The time a UE can be inactive before it is released is controlled by tInactivityTimer Current setting for tInactivityTimer is 10s, requirement from UE vendor Recommend to change to 30s to reduce signaling load for high capacity cells

For tInactivityTimer set to 30s, E-RAB drop rate will increase due to the E-RAB drops only consider the abnormal E-RAB Releases • if there was data in buffer (i.e. active).

•

Number of UEs stay in RRC_Connected state will be larger, larger, thus lowering the number of available Connected Users License for new users

Mp load 1.2 RRC Connection setup intensity (due to UE releases by rLC Supervision)  – cont’ •

•

As part of Radio Connection Supervision, RLC failures are caused by  –

T310 expiry

 –

Max RLC re-transmissions reached

T310 is controlled by  –

After receiving N310 consecutive “out -of-sync” indications, start timer T310

 –

After receiving N311 consecutive “in-sync” indications, stop timer T310

 –

After T310 expired  Radio Link Failure

 –

Current settings: •

N310 = 20 (recommended, no change)

•

N311 = 1 (recommended, no change)

•

T310 = 2s (recommended, no change)

 UE is released after T310 (2s) + T311 (3s)

Mp load 1.2 RRC Connection setup intensity (due to UE releases by rLC Supervision) •

RLC re-transmissions are controlled by  –

 –

Max # RLC re-transmissions re-transmissions before stopping and indicating to RRC max RLC re-tx reached •

SRB/DRB :: dlMaxRetxThreshold (Current setting: 8/8, recommended, no change)

•

SRB/DRB :: ulMaxRetxThreshold (Current setting: 8/8, recommended, no change)

Poll timer for RLC re-Tx (if no status report received) •

SRB/DRB :: tPollRetransmitDl (Current: 45ms/50ms, recommend 80ms/80ms)

•

SRB/DRB :: tPollRetransmitUl (Current: 45ms/50ms, recommend 80ms/80ms)

Re-Txx count Re-T

#1

…

Increase Poll timer may reduce SE/TTI usage for re-Tx and free SE/TTI for traffic, but re-Tx time is extended from 360-400ms to 640ms (80ms x 8)

Mp load 2. incoming handovers intensity

•

•

Current setting for handover is  –

ReportConfigEUtraBestCell::a3offset = 3dB

 –

ReportConfigEUtraBestCell:: hysteresisA3 = 1dB

 –

ReportConfigEUtraBestCell:: timeToTriggerA3 = 40ms

Propose to change a3offset to 5dB (handover margin increased to 6dB) for high capacity cells to reduce signaling load. a3offsetAnrDelta remains unchanged

Increase handover margin reduces handovers and may impact retainability Will review feasibility to use alternative approach on ‘UE Level Oscillating Handover Minimization’ feature

Mp load 3. hardware expansion

•

MP capacity for DUS is higher than MP capacity on DUL

Mp load •

pmProcessorLoad  –

•

 –

The total number of failed RRC connection establishments due to overload (Procedure Latency Supervision).

The number of Handover Preparation Failure messages sent by the target eNodeB due to high load (MP Load Ccontrol).

 pmHoPrepRejInOverload  –

•

The total number of failed RRC connection establishments due to high load (MP Load Control).

pmHoPrepRejInHighLoad  –

•

The number of discarded S1AP paging messages messages not routed to any cell due to high load (MP Load Control).

pmRrcConnEstabFailOverload  –

•

This counter counts the number of received S1AP paging messages in the RBS.

pmRrcConnEstabFailHighLoad  –

•

This counter also includes CPU load consumption from execution on priorities below traffic priorit y. This includes CPU load from performance management and some O&M tasks.

pmPagS1Discarded  –

•

A distribution of the CPU load of the MP corresponding to the definition of the CPU load used by MP Load Management.

pmPagS1Received  –

•

The average CPU load on the whole MP system (all the CPU cores).

pmProcessorLoadDistr  –

•

observability

The number of Handover Preparation Failure messages sent by the target eNodeB due to overload (Procedure Latency Supervision).

Focus areas •

LTE High Capacity Focus Areas 1. Con Control trol Chan Channe nell Dimen Dimensi sion onin ing g •

PUCCH Resources

•

PDCCH Resources

2. UL Noise Ri Rise 3. PRB Utiliz Utilizat ation ion / Cell Cell Through Throughput put Capacit Capacity y 4. MP Load •

RRC Connection Setup Intensity  –

Due to UE releases by Inactivity

 –

Due to UE releases by RLC Supervision

•

Incoming Handover Intensity

•

Hardware expansion

Connecte users icense ›

Current Connected Users Users License is 800 per DUL

›

Connected Users license should be topped-up for high traffic sites on demand basis

DUL

Rrc Conn user

DUL21

1500

DUL31

2500

DUL41

3000

Increase Connected Users License may have impact on signaling load

Connected Users License check is part of RRC Setup procedure

Connected users observability

•

pmRrcConnEstabFailLic  –

The total number of failed RRC Connection Establishments Establishments due to lack of connected users license

Focus areas •

LTE High Capacity Focus Areas 1.

Cont Contrrol Chan Channe nell Dime Dimens nsio ioni ning ng PUCCH Resources

•

PDCCH Resources

2.

UL Noise Rise

3.

PRB PRB Uti Utili lizzat atio ion n / Cell Cell Throu Through ghpu putt Cap Capaci acity ty

4.

MP Load •

5. •

•

RRC Connection Setup Intensity  –

Due to UE releases by Inactivity

 –

Due to UE releases by RLC Supervision

•

Incoming Handover Intensity

•

Hardware expansion Conn Connec ectted Use Users Lice Licens nse e

Summary of High Capacity Parameter Settings Settings

Parameter

Summary of high cap parameters Current

Recommended

noOfPucchSrUsers

320

640

Maximize number of allowed SR users

noOfPucchCqiUsers noOfPucchCqiUsers

320

640

Maximize number of allowed CQI users

CFI_AUTO_MAXIMUM CFI_AUTO_MAXIMUM  _3

CFI_AUTO_MAXIMUM_3 (no change)

pZeroNominalPucch

-117

-117 (no change)

pZeroNominalPusch

-96

-103

schedulingAlgorithm

3 (PROPORTIONAL_FAIR  _MEDIUM)

4 (PROPORTIONAL_FAIR_LOW) (PROPORTIONAL_FAIR_LOW) or 5 (MAXIMUM_C_OVER_I) (MAXIMUM_C_OVER_I)

tInactivityTimer

10s

30s

SRB/DRB::dlMaxRetxThreshold SRB/DRB::ulMaxRetxThreshold

8/8 8/8

8/8 (no change) 8/8 (no change)

45ms/50ms 45ms/50ms

80ms/80ms 80ms/80ms

T310 / T311

20 / 1

20 / 1 (no change)

Recommended setting is already set, for RLC supervision

N310 / N311

2s / 3s

2s / 3s (no change)

Recommended setting is already set, for RLC supervision

30 (3dB)

50 (5dB) (low priority)

pdcchCfiMode (10MHz)

SRB/DRB::tPollRetransmitDl SRB/DRB::tPollRetransmitUl

a3Offset

Objective

Recommended setting is already set, just monitor CCE and CFI usage Recommended setting is already set Reduce UL noise rise at high load Increase cell throughput and PRB utilization

Reduce signaling load Max # RLC re-Tx in UL/DL (control signaling load). Recommended setting is already set Increase poll timer for RLC re-Tx (if no status report received) to avoid RLC failures, reduce signaling load

Reduce signaling load. Will review feasibility to use alternative approach on ‘UE Level Oscillating Handover Minimization’ feature

THNAK YOU