1 © 2006 Nokia 13-468793 v1.0

Total in

terfe

ren

ce

NR

T reje

ction

rate

Spre

adin

g cod

e u

sage

HW

/ logical re

sou

rce

usage

Uplink

Downlink

Total p

ow

er

NR

T reje

ction

rate

Total interference

load

PS NRT capacity request

rejection rate

Lack of downlink spreading

codes

HW / logical resource limitation

Triggers set by operator

After ONE of the reasons is fulfilled cell is in the

load based handover state

Hard blocking ratio of

- BTS/WSP - AAL2

Triggering of Load based Handovers

2 © 2006 Nokia 13-468793 v1.0

LHOPwrOffsetUL = - 1.5 dB relative to PrxTarget

PrxTotal > PrxTarget + LHOPwrOffsetUL PtxTotal > PtxTarget + LHOPwrOffsetDL

LHOPwrOffsetDL = - 0.7 dB relative to PtxTarget

Headroom for CM triggering must be considered also

RNC checks based on RRI interval:

Triggering of Load based Handovers - Total interference load

PtxTotalNonHSDPA > PtxTargetHSDPA + LHOPwrOffsetDL

When HSDPA in use in the cell:

3 © 2006 Nokia 13-468793 v1.0

Measurement Report (e4a) Capacity Request

RNC internal Capacity Request (MAC layer)

CapaReqRejRateUL = RejectedRequestsCellUL

(AllCapacityRequestsCellUL + LHONRTTrafficBaseLoad )

CapaReqRejRateDL = RejectedRequestsCellDL

(AllCapacityRequestsCellDL + LHONRTTrafficBaseLoad )

CapaReqRejRateUL >

LHOCapaRejRateUL

CapaReqRejRateDL >

LHOCapaRejRateDL

RNC checks based on 1 sec intervals:

Triggering of Load based Handovers - PS NRT capacity request rejection rate

4 © 2006 Nokia 13-468793 v1.0

C 0 (0)=(1)

C 1 (0)=(1,1)

C 1 (1)=(1,-1)

C 2 (0)=(1,1,1,1)

C 2 (1)=(1,1,-1,-1)

C 2 (2)=(1,-1,1,-1)

C 2 (3)=(1,-1,-1,1)

C 3 (0)=(…)

C 3 (1)=(…)

C 3 (2)=(…)

C 3 (3)=(…)

C 3 (4)=(…)

C 3 (5)=(…)

C 3 (6)=(…)

C 3 (7)=(…)

Code Order 0 (SF 1)

Code Order 1 (SF 2)

Code Order 2 (SF 4)

Code Order 3 (SF 8)

ReservationRateSC(SF128) = ReservedSC

NumbAvailableSC 100 *

ReservationRate(SF128) > LHOResRateSC RNC checks based on RRI interval:

Triggering of Load based Handovers - Lack of downlink spreading codes

5 © 2006 Nokia 13-468793 v1.0

WSP capacity IuB AAL2 capacity

> LHOHardBlockingRatio NumberOfSamplesHardBlocking

(AllSamplesHWhuntDuringMeasPeriod + LHOHardBlockingBaseLoad ) 100 *

Triggering of Load based Handovers - HW or logical resources are limited • A load-based handover state is triggered due to HW or logical resource

(WBTS WSP capacity, IuB AAL2) congestion in the cell • Hard blocking occurs when a DCH setup attempt faces congestion of the

BTS or Iub AAL2 transmission capacity • ‘All samples’ is defined to be the number of successful and unsuccessful

BTS or Iub AAL2 transmission capacity hunts in the DCH setup attempts

6 © 2006 Nokia 13-468793 v1.0

Triggering of Load based Handovers – Parameters

• WCEL: LHOPwrOffsetUL – Range and step: -10..0 dB, step 0.1 dB (Default value: -0.7 dB)

• WCEL: LHOPwrOffsetDL – Range and step: -30..0 dB, step 0.1 dB (Default value: -1.5 dB)

• WCEL: LHOCapaRejRateUL – Range and step: 0..100 %, step 1 % (Default value: 70 %)

• WCEL: LHOCapaRejRateDL – Range and step: 0..100 %, step 1 % (Default value: 70 %)

• WCEL: LHONRTTrafficBaseLoad – Range and step: 0..255, step 1 (Default value: 10)

• WCEL: LHOResRateSC – Range and step: 0..100 %, step 1 % (Default value: 80 %)

• WCEL: LHOHardBlockingRatio – Range and step: 0..100 %, step 1 % (Default value: 50 %)

• WCEL: LHOHardBlockingBaseLoad – Range and step: 0..255, step 1 (Default value: 10)