Nokia 3G LBHO Trigerring

Triggering of Load based Handovers Triggers set by operator

 T   o  t    a  l    p  o  w  e  r 

Total interference load 1

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 T   o  t    a  l    i    n  t    e  r   f    e  r   e  n  c   e

 N  R   T   r   e  j    e  c   t    i    o  n  r   a  t    e

PS NRT capacity request rejection rate

 N  R   T   r   e  j    e  c   t    i    o  n  r   a  t    e

 S   p  r   e  a  d   i    n  g  c   o  d   e  u  s   a  g  e

Lack of  downlink spreading codes

 H  W  /    l    o  u  g  i    s   a  c   g  a  e  l    r   e  s   o  u  r   c   e

HW / logical resource limitation

Hard blocking ratio of  - BTS/WSP - AAL2

Uplink Downlink After ONE of the reasons is fulfilled cell is in the load based handover state

Triggering of Load based Handovers Total interference load RNC checks based on RRI interval:

PrxTotal > PrxTarget + LHOPwrOffsetUL PtxTotal > PtxTarget + LHOPwrOffsetDL When HSDPA in use in the cell:

PtxTotalNonHSDPA > PtxTargetHSDPA + LHOPwrOffsetDL LHOPwrOffsetUL = - 1.5 dB relative to PrxTarget

2

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LHOPwrOffsetDL = - 0.7 dB relative to PtxTarget

Headroom for CM triggering must be considered also

Triggering of Load based Handovers PS NRT capacity request rejection rate

Measurement Report (e4a) Capacity Request

RNC internal Capacity Request (MAC layer)

RejectedRequestsCellUL CapaReqRejRateUL = (AllCapacityRequestsCellUL + LHONRTTrafficBaseLoad ) RejectedRequestsCellDL CapaReqRejRateDL = (AllCapacityRequestsCellDL + LHONRTTrafficBaseLoad )

RNC checks based on 1 sec intervals:

3

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CapaReqRejRateUL > LHOCapaRejRateUL CapaReqRejRateDL > LHOCapaRejRateDL

Triggering of Load based Handovers Lack of downlink spreading codes C 2 (0)=(1,1,1,1) 

1 (0)=(1,1)  C 

C 2 (1)=(1,1,-1,-1)  C 0 (0)=(1)  C  2 (2)=(1,-1,1,-1)  C  1 (1)=(1,-1)  C  2 (3)=(1,-1,-1,1) 

Code Order 0 (SF 1)

Code Order 1 (SF 2)

Code Order 2 (SF 4)

ReservationRateSC(SF128) = 100 *

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 3 (SF 8)

ReservedSC NumbAvailableSC

RNC checks based on RRI interval:

4

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ReservationRate(SF128) > LHOResRateSC 

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Triggering of Load based Handovers HW orhandover logical A load-based stateresources is triggered due toare HW orlimited 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

WSP capacity

IuB AAL2 capacity

NumberOfSamplesHardBlocking

100 *

5

> LHOHardBlockingRatio (AllSamplesHWhuntDuringMeasPeriod + LHOHardBlockingBaseLoad )

© 2006 Nokia

Triggering of Load based Handovers – Parameters •

WCEL: LHOPwrOffsetUL  –

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WCEL: LHOPwrOffsetDL  –

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Range and step: 0..100 %, step 1 % (Default value: 50 %)

WCEL: LHOHardBlockingBaseLoad   –

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Range and step: 0..100 %, step 1 % (Default value: 80 %)

WCEL: LHOHardBlockingRatio  –

•

Range and step: 0..255, step 1 (Default value: 10)

WCEL: LHOResRateSC   –

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Range and step: 0..100 %, step 1 % (Default value: 70 %)

WCEL: LHONRTTrafficBaseLoad   –

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Range and step: 0..100 %, step 1 % (Default value: 70 %)

WCEL: LHOCapaRejRateDL  –

•

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

WCEL: LHOCapaRejRateUL  –

•

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

Range and step: 0..255, step 1 (Default value: 10)

© 2006 Nokia