3 RAN Performance Tuning NOKIA

1 © NOKIA RAN_c_pe.PPT / 18-03-2004 / JRe

RAN Performance Tuning

Reunanen Jussi

18.03.2004


IntroductionUE is powered up

• The call performance is divided into 7 sections starting from the initial cell search all the way to call release

• In each section:• relevant counters for performance evaluation and

trouble shooting • parameters for performance improvement

• are presented

Cell search

Cell Selection and Cell Reselection

RRC Connection Establishment

RAB Establishment

Handovers; SHO, ISHO, IFHO

RRC Active Releases

RAB Active Releases


UE is powered up

Idle Mode PerformanceCell search

• DL Scrambling code info is needed for cell search procedure & frame syncronization

• Each cell has own DL primary scramling code (cell identification)

• Codes are divided to Primary and secondary Scrambling codes • Each cell is allocated one and only one primary scrambling code. The

primary CCPCH, primary CPICH, PICH, AICH and S-CCPCH carrying PCH are always transmitted using the primary scrambling code.

• The total number DL primary scrambling codes is 512, subdivided into 64 groups each of 8 primary scrambling codes

• Each Primary Scrambling code could have up to 15 secondary scrambling codes


UE is powered up


• The allocation of DL Scrambling code in neighbouring cells is possible in two ways:

• Random code planning approach: Use any of the 512 codes• Use of 64 SC groups i.e. allocating SC groups cell by cell

• Which ever planning approach is used, large enough separation (reuse 64) between two cells using the same scrambling code must be guaranteed

• The best code planning strategy depends on the UE algorithm

• However the cell search performance difference between the two primary SC methods is negligible

• Cell search performance gain decreases when the number of neighbours are increased


UE is powered up


C256,0

C256,1

CPICH

BCH

S-SCH

P-SCH

Allchannels

CSF,n

Scrambling Code

∑

∑


UE is powered up


When searching cells:

The UE measures the impulse response first by using the P-SCH , which is unique in the whole system.

! By finding a delay, which produces a local maximum correlation with this code, the UE gets slot and symbol synchronisation with a base station/sector (matched filter).

! The correlation peaks of different cells appear with different delays. This is achieved by offsets in the transmission time of the search symbols and partly by different propagation delays.


UE is powered up


After the UE gets the slot/symbol synchronisation it can use the S-SCH to find the frame synchronisation and to identify the code group to which the cell's scrambling code belongs to.

! This is required at least in the initial power on.

! The 2nd Synchronisation channel's code changes from slot to slot in a sequence which has a period of 15 slots (i.e. 1 frame). There are 64 sequences chosen each defining a code group for the actual scrambling code of the cell.

! By solving this sequence the UE gets the frame synchronisation with the BS and identifies the code group from which the scrambling code of the BS has been taken.


UE is powered up


UE knows the scrambling codes of each scrambling code group and finally after finding the right code, which is given on P-CPICH UE can start decoding the BCH.

! If the UE has a neighbour list available the search procedure may be different.

! The cell is found when its primary scrambling code has been identified.


UE is powered up


Cs1 Cs2 Cs15

Cp = Primary Synchronisation CodeCs = Secondary Synchronisation Code

CP CP CP

2560 Chips 256 Chips

Slot 1 Slot 14Slot 0

10 ms Frame


UE is powered up


64 D

iffe

rent

com

bina

tion

Sequence of length 15 Matrix made by 16 different codes

5th row matches with the secondary

SCH channel


UE is powered up


8 Di

ffer

e nt

C od e

s

64 Different group

5th row, theCell Scrambling code is

within that group

Total number of Scrambling Code 64 x 8 = 512


Idle Mode Performance Cell Selection and Cell Reselection

• The UE should always be connected to the best cell: highest CPICH RSCP and Ec/No to avoid several consecutive RRC Connection Request

• The more RRC Connection Requests are sent by the UE the worse is the call setup delay cumulative distribution function



• The UE should always be connected to the best cell: highest CPICH RSCP and Ec/No to avoid several consecutive RRC Connection Request

• Call setup failure performance gets worse by the decreasing CPICH RSCP & Ec/No

QqualMin = -20dB

Calls setups failures

Calls setups difficult

Calls setups ok

Calls setups very successful

Recommended area

CPICH RSCP CPICH Ec/No

QqualMin+Sintrasearch+Qhyst2= -16dB + 4dB = -12dBQqualMin+Sintrasearch=-20dB + 4dB = -16dB

Time



Initial cell selection/Stored InformationCell Selection to find suitable cell

Initial cell selection/Stored InformationCell Selection to find suitable cell

UE scans all RF channels in UTRA band of the selected PLMN or stored info is used

Suitable cell is checked with S-criteria Suitable cell is checked with S-criteria Both level & quality should be checked.

After camped normally to suitable cell re-selection process can start

After camped normally to suitable cell re-selection process can start UE measures the cells from neighboring

list of the own cell

Cell are prioritized with H-criteria in case HCS is used

Cell are prioritized with H-criteria in case HCS is used

If HCS is not used R-criteria is useddirectly

Cells are ranked with R- Criteria for highest HCS prio (not for fast moving UE)

Cells are ranked with R- Criteria for highest HCS prio (not for fast moving UE)

Ranking is starting from Highest HCS priorities & cells passing the H-criteriaFor fast moving UEs ranking starts fromlowest HCS priorities

Cell re-selection to Highest R is done forall the cells that fulfill S-criteria

Cell re-selection to Highest R is done forall the cells that fulfill S-criteria

After this cell will be selected by the UE and it will be checked if the cell will be suitable to camp on



HCS in use: HCS not in use:

S-Criteria OK

Cells with Highest HCSPriorities &

H > 0

Serving + measuredneighboring cells

S-Criteria OK

Serving cell+ measuredneighboring cells

Cells with Lower HCSPriority than

in Serving cell

Fast MSIf No Cellwith H>0accept allneighbors

BestR

BestR

BestR



• The cell selection criteria S are defined as:

• The cell selection criterion S for a suitable cell is fulfilled when:

• Where:

Squal = Qqualmeas – QqualMinSrxlev = Qrxlevmeas – QrxlevMin - Pcompensation

Squal > 0 AND Srxlev > 0

dBmMaximum RF output power of the UEP_MAX

21-50 .. 33dBmDefines the maximum transmission power level a UE can use on PRACH. Parameter is part of SIB 3

UEtxPowerMaxPRACH

dBmax(UEtxPowerMaxPRACH – P_MAX,0)Pcompensation

-115-115 .. -252dBm step

dBmThe minimum required RX level in the cell (RSCP). Parameter is part of SIB 3QrxlevMin

-20-24 ..01dB step

dBThe minimum required quality level in the cell (Ec/N0). Parameter is part of SIB 3QqualMin

dBmMeasured cell Rx level. For FDD cells it CPICH RSCP, for GSM cells RxLEV and for TDD cell P-CCPCH RSCP

Qrxlevmeas

dBMeasured cell quality value, it is expressed in CPICH Ec/No. Not applicable for GSM or TDD cellls.

Qqualmeas

dBCell Selection Rx level value.Srxlev

dBCell Selection quality value. Not applicable for GSM or TDD cells.Squal

DefaultRangeUnitDescriptionName



First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)

Rs = CPICH RSCP/GSM RSSI + Qhyst1Rn= CPICH_RSCP(n) or RXLEV(n) - Qoffset1 -

temp_offset1_during_penalty

R - criteria Serving WCDMA cell calculation, with

hysteresis parameter

No

Second ranking only for WCDMA cells based on CPICH Ec/No

Rs = CPICH Ec/No + Qhyst2Rn= CPICH Ec/No -Qoffset2 -temp_offset2_during_penalty

Neighbour WCDMA or GSM cell calculation with offset

parameter

Rn higher in GSM cellYes

Penalty & temp_offset1is used in case HCS is used

and neighbour is having same priority.

Cell re-selection to GSM

Temp offset2 is used only in case HCS is used and

neighbour is having same priority

Cell re-selection to WCDMA cell of highest

R value



• Parameters Sintrasearch, Sintersearch and SsearchRAT are compared with Squal (CPICH Ec/No -Qqualmin) in S-criteria for cell re-selection

Sintrasearch Sintersearch SsearchRAT

?WCDMA

CELL

1234

Region Condition Neighbour cells to be measured

1 Squal > Sintrasearch None

2 Sintersearch < Squal ≤ Sintrasearch Intra-frequency cells

3 SsearchRATm < Squal ≤Sintersearch

Intra- and inter-frequency cells

4 Squal ≤ SsearchRATm Intra-, inter-frequency and inter-RAT cells



Qmeas (CPICH Ec/No)

t

Serving Cell

Neighbor Cell

Qhyst2

R

Qoffset2

SintersearchSsearchRAT

Rn > Rs => Cell re-selection

Rs

Rn Qoffset2 and Qhyst2 define the total margin that neighbour cell quality needs to be higher

than serving cell quality



• Best performance can be found by tuning the following parameters and maximising the CSSR and minimising the number of consecutive RRC Connection Requests sent by the UE

• Cell reselection triggering time (e.g. Treselection = 0s)• Reselection takes place immediately when the UE notices that there is

difference between the cells’ Ec/No values (in worst case scenario there can be up to 3dB + Qhyst difference based on the measurement accuracy requirement before the UE performs cell reselection)

• Cell reselection hysteresis 2 (e.g. Qhyst2 = 4dB)• This will add 4dB hysteresis to the neighboring cell evaluation (target for

the cell reselection)• Note that Qhyst1 is used only in case the cell selection and re-selection

quality measure is set to CPICH RSCP (default is CPICH Ec/No so Qhyst 1 is not used in intra-FDD reselection)

• Cell Re-selection Quality Offset 2 (e.g. AdjsQoffset2 = 0dB)• This parameter is used in the cell re-selection and ranking between WCDMA

cells. The value of this parameter is subtracted from the measured CPICH Ec/No of the neighbor cell before the UE compares the quality measure with the cell re-selection/ ranking criteria

• S intrasearch (e.g. Sintrasearch = 4dB)• This parameter is used by the UE to calculate the threshold (CPICH Ec/No) to

start intra frequency (SHO) measurements (Sintrasearch above QqualMin value)

• Minimum required quality level in the cell (e.g. QqualMin = -20dB)



• New set Case : Sintrasearch = 12 dB, Treselection = 0 sec and Qhyst2 =0 dB

-18

-16

-14

-12

-10

-8

-6

-4

-2

CPI

CH

Ec/

No

[dB

]

All Call Attempts: New

• Between location area borders it might be good to have some hysteresis between the adjacent LA cells -> Qhyst2 = 2dB or 4dB


Connection Establishment UE - RAN RRC Connection Establishment

• The power level for sending of the RRC Connection Request –message is set/calculated by the UE

• Uplink open loop PC take place at the random access procedure:

• UE measures the received power of the CPICH which reported back in "measured results on RACH" IE in: initial direct transfer (UTRAN must extract this IE from the NAS message), cell update / ura update, measurement report (UL traffic volume measurement report), RRC connection request, uplink direct transfer (UTRAN must extract this IE from the NAS message)

[RACH] RRC:RRC Connection Request

NBAP: RL Setup Request

NBAP: RL Setup Response

ALCAP:ERQ

ALCAP:ECF

[FACH] RRC: RRC Connection Setup

UE Node B RNC

• Transmission power of CPICH (SIB5&6), total received uplink power at BS (SIB7) and a parameter value PRACHRequiredReceivedCI are sent from BS in system information broadcast messages (SIB5&6)

• Based on this information UE calculates the transmission power of the first pre-amble of PRACH ptx

• ptx = CPICHtransmissionPower-RSCP(CPICH)+RSSI(BS)+"constant value“

where the "constant value" is the value of the RNC parameter PRACHRequiredReceivedCI

[DCH] RRC: RRC Connection Setup Complete

NBAP: Synchronisation Indication

L1 Synchronisation



• If no acquisition indicator is received UE raises the transmission power by PowerRampStepPRACHpreamble which is a broadcast parameter

• This procedure is repeated until acquisition indicator is received, after which UE sends the RACH message at power which offset by PowerOffsetLastPreamblePRACHmessagefrom the last preamble




ALCAP:ERQ

ALCAP:ECF


UE Node B RNC

DownlinkBS

P1

L1 ACK / AICH

UplinkMS Preamble

1

Not detected

Message partPreamble2

P2

• PRACH_preamble_retrans parameter determines how many times PRACH preamble can be sent (without AICH response) within one preamble ramping cycle (SIB5&6)

• RACH_tx_Max defines how many times the PRACH pre-amble ramping cycle procedure can be repeated before UE MAC reports a failure on RACH transmission to higher layers (SIB 5&6)



• Some of the early UEs are not capable of performing Open Loop PCaccurately i.e. they have problems in RRC Connection Establishment

• The UE cannot detect the SIB7 UL interference level correctly or cannot measure the CPICH RSCP accurately enough

• The situation can be corrected by increasing the parameter valuePRACH_preamble_retrans or RACH_tx_Max

• Increasing the parameter values should be made with extra care as increasing the maximum UE TX power on RACH increases the UL load is as well

• In case of problematic site which does not answer to PRACH at all due to BTS problems; increasing the power on RACH increases the UL interference on the surrounding sites


• For failed calls the UE Tx vs. CPICH Ec/No and CPICH RSCP should be investigated in order to see possible DL coverage or open loop PC problems

•In case CPICH RSCP is low but UE Tx Power is low

•There is possibility that UE open loop PC is not working correctly•Or the CPICH Tx power is pretty low and there is DL coverage problems•Or the SCCPCH power offset to CPICH power is set wrongly – too big offset

•In case CPICH Ec/No is low but the UE Tx power is low then there could be some problem in DL quality - provided that the CPICH RSCP is ok

•Some high DL loading in the cell•Pilot pollution on that area

-120-110-100-90-80

-70-60-50-40

-40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25UE Tx Power [dBm]

RSC

P [d

Bm

]

-40

-30

-20

-10

0

10

20

30

-30 -25 -20 -15 -10 -5 0

CPICH Ec/No [dBm]

UE

Tx P

ower

[dB

m]

[dB]


Connection Establishment UE - RAN



• From CPICH Ec/No vs. CPICH RSCP it can be seen that only a few call failures are having relatively good CPICH RSCP but still pretty poor CPICH Ec/No:

•indicating possibility of Pilot Pollution•Indicating possibility of relatively high DL load

• Those cells in case they constantly do have this kind of phenomena should be investigated more

-120

-110-100

-90-80

-70

-60-50

-40-30 -25 -20 -15 -10 -5 0

CPICH Ec/No [dB]

CPI

CH

RSC

P [d

Bm

]• For possible pilot pollution investigation the

amount of SCs and their strength can be plotted from the drive test data and possible the cells causing the pilot pollution can be identified and dominance optimisation can be done

Plot of RSCP and Ec/No vs Data No. in problem Area

-140

-120

-100

-80

-60

-40

-20

0

Data No.

RSC

P an

d R

SSI (

dBm

)

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

ANT1_RSSI SC97 RSCP SC106 RSCP SC103 RSCP SC69 RSCPSC174 RSCP SC180 RSCP SC97 Ec/No SC106 Ec/No SC103 Ec/NoSC69 Ec/No SC174 Ec/No SC180 Ec/No

Ec/N

o (d

B)

Pilot pollution area/poordominance area



Timer T300 is started


ALCAP:ERQ

ALCAP:ECF

NBAP: RL Setup RequestNBAP:RL Setup Request

BTS Starts sending DPCCH: Pilot and TPC & Starts UL synchronization

procedure

Start TX/RX

Start TX/RX

UE start sending DPCCH for UL sync purposes (pilot) after DL frame sync is established

RNC sends RRC Connection Setup -message



BTS sends: NBAP RADIO LINK SETUP

RESPONSE -message

S

UE Node B RNC

1UE sends RRC Connection Request -messageL1 Synchronisation



• When the UE has established the frame synchronization to the downlink DPCH, it starts the transmission of the uplink DPCH

• The DPDCH is transmitted only when there are Transport Blocks received from the UE L2


RNC receives RRC Connection Setup Complete –message ->

RRC Connection Setup Complete –message SENT

L1 Synchronization established

BTS sends NBAP: SYNCHRONIZATION

IDICATION -messageTimer T312 started

“in sync” indicators on L1

Timer T312 stopped

L1 Synchronization

established

N_INSYNC_IND indicators on L1

1


UE Node B RNC

ALCAP:ERQ

ALCAP:ECF


Start TX/RX

Start TX/RX





L1 Synchronisation

• When a physical dedicated channel establishment is initiated by the UE, the UE starts a timer T312 and wait for layer 1 to indicate N312 "in sync" indications

• On receiving N312 "in sync" indications, the physical channel is considered established and the timer T312 is stopped and reset

• On the BTS side after receiving synchronisation indicators the BTS sends NBAP: SYNCHRONIZATION INDICATION –message to RNC after which the closed loop and outer loop PC start to control the powers


Connection Establishment UE - RAN

UE initiates physical dedicated channel establishment before sending e.g. RRC Connection Setup Complete –message on DPDCH N312 L1 “in sync”

indicators

Other cases HHO, FACH=>DCH-state transitions



• In case UE is not able to establish synchronization within timer T312 it stops TX on the DCH

• In case BTS is not able to establish synchronization it does not send NBAP:Synchronization Indication –message to RNC

• The BTS tries to establish synchronization until RNC sends NBAP:Radio Link Deletion -message


ALCAP:ECF


UE Node B RNC


Start TX/RX

ALCAP:ERQ


Start TX/RX

L1 Synchronisation



• Longer time (T312 high and high N312) (T312 high and high N312) the UE has to establish the L1 synchronization the higher probability successful physical channel establishment is and better call set up success rate

• However longer the time for L1 synch the longer is call setup time

• During the test it was noted that setting N312 to 2 or 4 (between 1 and 2 there is notable difference) does not have any significant effect on the call set up success rate

• But the effect on the call set up time is significant and therefore N312 value of 2 was selected to be used

AMR performance

0%

10%

20%30%

40%

50%

60%

70%80%

90%

100%

14/0

1/03

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1/03

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15/0

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3/03

06/0

3/03

07/0

3/03MO

C /

MTC

cal

l set

up d

elay

5 s

ec P

erce

ntile

Percentile MOC call setup delay @5 sec

Percentile MTC call setup delay @5 sec

N312N312=4=4

N312N312=1=1

N312N312=2=2

17/0

3/03



• Way to improve RRC Connection success rate• Improve the UE idle mode behavior by making the intra-frequency

measurements earlier and cell reselection more aggressive • Adjust the T312 and N312 values

• RRC Connection Success rate can be low due to:• UE changing cell during RRC Connection Setup phase (cell A -> cell B) • RRC Connection Setup –message is not heard by the UE



UE RNCBTS CN

RRC Setup and Access Complete Ratio [%]100*[Sum(1001C8)/Sum(1001C0)]

RRC: Initial Direct Transfer

RANAP: Initial UE Message

RRC Connection Active phaseUE-CN Signaling

RRC Connection Active completedTriggers: 1001C12 RRC Con Active Comp

RANAP: Iu Release Command

Special Reason: RRC Connection Active Release Due to Triggers: 1001C13 SRNC Relocation 1001C14 Pre-emption

RRC Drop Ratio [%]100-100*[Sum(1001C12+1001C13+1001C14)/Sum(1001C8)]

RRC: Connection RequestCorrectly Received messageRRC Connection Setup StartsTriggers: 1001C0 RRC Connection Attempt

RRC Connection Setup phaseResource Reservation in RNC, BTS, Transmission

RRC: RRC Connection Request SetupRRC Connection setup completedTriggers: 1001C1 RRC Con Setup Compl

RRC Connection Access phase RNC waits reply from UE

RRC: RRC Connection CompletedRRC Connection Access completedTriggers: 1001C8 RRC Con Acc Comp

RRC Setup Complete Ratio [%]100*[Sum(1001C1)/Sum(1001C0)]



RNC

RRC: Connection RequestCorrectly Received messageRRC Connection Setup StartsTriggers: 1001C0 RRC Connection Attempt

BTS




RRC: RRC Connection Completed


CN


RRC Connection Access completedTriggers: 1001C8 RRC Con Acc Comp


Failure Case:RRC Connection Active failsDue to Triggers: 1001C15 Iu interface 1001C16 Radio interface1001C17 BTS1001C18 Iur interface1001C19 Ciphering failure1001C20 Integrity check1001C21 RNC internal reasonRANAP: Iu Release Command


Special Reason: RRC Connection Active Release Due to Triggers: 1001C13 SRNC Relocation 1001C14 Pre-emption

Failure Case:RRC Connection Setup failsDue to Triggers: 1001C2 Handover control1001C3 Admission control1001C4 BTS1001C5 Transmission network1001C6 RNC internal reason1001C7 Frozen BTS

UE

Failure Case:RRC Connection Access failsDue to Triggers: 1001C9 L1 synchronization in BTS1001C10 UU interface1001C11 RNC internal reason


UE RNC

RRC: Connection Request

Correctly Received messageTriggers: 1001C0 RRC Connection Attempt

BTS




RRC: RRC Connection Completed


CN


RRC Connection Access completedTriggers: 1001C8 RRC Con Acc Comp


RANAP: Iu Release Command


RRC Connection Setup due to CauseTriggers: 1001C22 MOC conv call att1001C24 MOC stream call att1001C26 MOC interac call att1001C28 MOC backgr call att1001C30 MOC subscribed call att1001C32 MTC conv call att1001C34 MTC stream call att1001C36 MTC interac call att1001C38 MTC backgr call att1001C40 Emergency call att1001C42 Inter RAT cell reselection1001C44 Inter RAT cell chng ord1001C46 Registration attempt1001C48 Detach attempt1001C50 MOC high prior signaling1001C52 MTC high prior signaling1001C54 MOC low prior signaling1001C56 MTC high prior signaling1001C58 Call re establishment att1001C60 Terminating cause unknown

RRC Connection EstablishmentConnection Establishment UE - RAN

Failures by RRC Connection Setup CausesTriggers: 1001C23 MOC conv call failure1001C25 MOC stream call failure1001C27 MOC interac call failure1001C29 MOC backgr call failure1001C31 MOC subscribed call fail1001C33 MTC conv call failure1001C35 MTC stream call failure1001C37 MTC interac call failure1001C39 MTC backgr call failure1001C41 Emergency call failure1001C43 Inter RAT cell reselec fail1001C45 Inter RAT cell chng ord fail1001C47 Registration attempt fai1001C49 Detach attempt failure1001C51 MOC high prior sig failure1001C53 MTC high prior sig failure1001C55 MOC low prior sig failure1001C57 MTC high prior sig failure1001C59 Call re establishment fail1001C61 Terminating cause unknown failure


Correctly Received messageRRC Connection RequestTriggers: 1001C0 RRC Connection Attempt

AC to check to accept or reject RRC

Connection Request

[FACH] RRC:RRC Connection Reject : Cause Unspecified In case the UL load (measured PrxTotal) exceeds

PrxTraget + PrxOffset or Prx_nc exceeds PrxTarget

Counter M1002C1 DCH Request for Signaling Link Reject in UL in SRNC


UE Node B RNC


M1002C3 DCH Requests for RRC Connection in SRNCM1002C0 DCH Request for Signaling Link in SRNC – includes SHO

DCH allocation rejection triggers:M1001C3 RRC Connection Setup Failure due to Admission Control


Correctly Received messageRRC Connection RequestTriggers: 1001C0 RRC Connection Attempt

M1002C3 DCH Requests for RRC Connection in SRNCM1002C0 DCH Request for Signaling Link in SRNC – includes SHO

[FACH] RRC:RRC Connection Reject : Cause Unspecified


UE Node B RNC



Connection Request

In case the DL load (measured PtxTotal) exceeds PtxTraget + PtxOffset or Ptx_nc exceeds the PtxTarget

Counter M1002C2 DCH Request for Signaling Link Reject in DL in SRNCDCH allocation rejection triggers:

M1001C3 RRC Connection Setup Failure due to Admission Control





Start TX/RX

NBAP: RL Setup Failure

RL allocation rejection triggers:M1001C4 RRC Connection Setup Failure due to BTS Reasons

UE Node B RNC Correctly Received messageRRC Connection RequestTriggers: 1001C0 RRC Connection Attempt


Connection RequestM1002C0 DCH Request for Signaling Link in SRNCM1002C3 DCH Requests for RRC Connection in SRNC

Successful AC decision triggers:M1002C7 DCH Allocation for Signaling Link 3.4kbps in SRNC

M1005C0 Radio Link Setup Attempt for First Radio Link[FACH] RRC:RRC Connection Reject : Cause

Unspecified

M1005C13 Radio Link Setup Failure for First Radio Link due to Not Enough Resources

M1005C15 Radio Link Setup Failure for First Radio Link due to BTS General Reason





Start TX/RX

NBAP: RL Setup Response M1005C0 Radio Link Setup Attempt for First Radio Link

M1005C5 Radio Link Setup Success for First Radio Link

ALCAP:ERQ

ALCAP:ECF

UE Node B RNC Correctly Received messageRRC Connection Setup StartsTriggers: 1001C0 RRC Connection Attempt


Connection RequestM1002C0 DCH Request for Signaling Link in SRNCM1002C3 DCH Requests for RRC Connection in SRNCSuccessful AC decision triggers:M1002C7 DCH Allocation for Signaling Link 3.4kbps in SRNC

[FACH] RRC:RRC Connection Reject : Cause Unspecified

Failure in AAL2 connection setups triggers RRC Connection Rejectmessage and:

M1001C5 RRC Connection Setup Failure due to Transmission




ALCAP:ERQ

Start TX/RX


NBAP: RL Setup Failure

ALCAP:ECF

Failure in receiving the RRC Connection Setup Complete1) And missing NBAP Synchronisation Indication:

M1001C9 RRC Connection Access Failure due to Radio Interface Synchronisation is updated

2) NBAP Synchronisation Indication is received : M1001C10 RRC Connection Failure due to Uu Interface

UE Node B RNC


Connection Request

NBAP: RL Setup Request Sent RRC Connection Setup –message triggers:M1001C1 RRC Connection Setup Complete

Start TX/RX

L1 Synchronisation



Received RRC Connection Setup Complete –message triggers:M1001C8 RRC Connection Access Complete


RAB Establishment

Radio Link Reconfiguration Commit

AAL2SIG:ERQ

RAB Assignment Request

FacilityCall Proceeding

SetupSecurity Mode Complete

Security Mode CommandCommon ID

MGW

RRC Connection EstablishmentInitial Direct Transfer (CM Service Request) SCCP: Connection Request

SCCP: Connection ConfirmLocation Reporting Control

Radio Link Reconfigure PrepareRadio Link Reconfigure Ready

AAL2SIG:ERQAAL2SIG:ECF

FP: Downlink SyncFP: Uplink Sync

AAL2SIG:ECF

Radio Bearer SetupRadio Bearer Setup Complete

RAB Assignment Response

AlertingConnect

Connect Acknowledge

Call Established

RAB EstablishmentUE Node B RNC


RAB Establishment RAB Establishment

BTS RNC CNUE

B Ass

: R

RANAP: RAB Assignment Request

RRC: Radio Bearer Setup

RRC: Radio Bearer Setup Completed

RANAP: RAB Assignment Response

RRC: Radio Bearer Release

RRC adio Bearer Reconfiguration Complete

RANAP: RA ignment Response

RAB Setup phaseResource Reservation in RNC, BTS, Transmission

RAB Setup Complete Ratio [%]100*[Sum(1001C73…79)/Sum(1001C66…72)]

RAB Setup and Access Complete Ratio [%]100*[Sum(1001C115..121)/Sum(1001C66…72)]

RAB Connection Access phase RNC waits reply from UE

RANAP: RAB Assignment Request, with IE: RAB ReleaseRAB Drop Ratio [%]100-100*[Sum(1001C136…142+1001C143+1001C144+1001C151…154+1001C167…172)/Sum(1001C115…121)]



UE BTS



RRC: Radio Bearer Setup

RAB Setup phaseResource Reservation in RNC, BTS, Transmission

RAB Setup startsDepending on RAB TypeTriggers: 1001C66 RAB setup att for CS Voice1001C67 RAB setup att for CS Data conv class1001C68 RAB setup att for CS Data stream class1001C69 RAB setup att for PS Data conv class1001C70 RAB setup att for PS Data stream class1001C71 RAB setup att for PS Data intera class1001C72 RAB setup att for PS Data backgr class

Failure Case:CS RAB Setup for Voice fails Due to Triggers: 1001C80 Admission control1001C81 BTS1001C82 Transmission network1001C83 RNC internal reason1001C84 Frozen BTSNote: Each RAB typehas identical failure counters

RRC: Radio Bearer Setup Completed


RAB Connection Access phase RNC waits reply from UE

RAB Access CompletedTriggers: 1001C115 RAB setup acc comp for CS Voice1001C116 RAB setup acc comp for CS Data conv class1001C117 RAB setup acc comp for CS Data stream class1001C118 RAB setup acc comp for PS Data conv class1001C119 RAB setup acc comp for PS Data stream class1001C120 RAB setup acc comp for PS Data intera class1001C121 RAB setup acc comp for PS Data backgr class

Failure Case:CS RAB Access for Voice fails Due to Triggers: 1001C122 UE1001C123 RNC internalNote: Each RAB typehas identical failure counters

RAB Active phaseUser Plane Data Transfer

RNC CN

RAB Setup CompletedDepending on RAB TypeTriggers: 1001C73 RAB setup comp for CS Voice1001C74 RAB setup comp for CS Data conv class1001C75 RAB setup comp for CS Data stream class1001C76 RAB setup comp for PS Data conv class1001C77 RAB setup comp for PS Data stream class1001C78 RAB setup comp for PS Data intera class1001C79 RAB setup comp for PS Data backgr class



UE BTS

RANAP: RAB Assignment Request, with IE: RAB reconfiguration

RRC: Radio Bearer Reconfiguration

RAB ReconfigurationResource Reconfigured in RNC, BTS, Transmission

RRC: Radio Bearer Reconfiguration Complete


RAB Active phaseUser Plane Data Transfer Special Reason:

RAB Active Release Due to Triggers: 1001C143 SRNC Relocation for CS Voice1001C144 Pre-emption for CS VoiceFor all types of RABs

RAB Reconfiguration Attempt Triggers: 1001C197 RAB reconf AttFor all types of RABs

RANAP: RAB Assignment Request, with IE: RAB Release

RRC: Radio Bearer Release

RRC: Radio Bearer Reconfiguration Complete


RAB ReleaseResource Released in RNC, BTS, Transmission

RNC CN

RAB Reconfiguration FailureTriggers: 1001C198 RAB reconf FailFor all types of RABs

RAB Active CompletedDepending on RAB TypeTriggers: 1001C136 RAB Act Comp for CS Voice1001C137 RAB Act Comp for CS Data conv class1001C138 RAB Act Comp for CS Data stream class1001C139 RAB Act Comp for PS Data conv class1001C140 RAB Act Comp for PS Data stream class1001C141 RAB Act Comp for PS Data intera class1001C142 RAB Act Comp for PS Data backgr class



AC to check to accept or reject RAB

Assignment Request

RAB Establishment

RANAP: RAB Assignment RequestTriggers: M1003C8 RAB ASS REQ BY CN1001C66 RAB setup att for CS Voice…1001C72 RAB setup att for PS Data backgr class

M1002C12 RT DCH REQ FOR CS VOICE CALL IN SRNC – includes SHOM1002C15 RT DCH INIT REQ FOR CS VOICE CALL IN SRNCM1002C16 RT DCH DHO REQ FOR CS VOICE CALL IN SRNC

In case the UL load (measured PrxTotal) exceeds PrxTraget + PrxOffset or Prx_nc + ∆ Prx_nc exceeds PrxTarget

Counter M1002C13 RT DCH REQ FOR CS VOICE CALL REJECT IN UL IN SRNC is updated – includes SHO

Same separately for:CS Conversational classCS Streaming classPS Conversational classPS Streaming classPS Interactive classPS Background class

RANAP: RAB Assignment Responsepower

load

max planned load

max planned power

?

RAB EstablishmentUE Node B RNC MGW

In case the RAB assignment fails due to AC, counters:M1003C13 RAB ASS NONSUCC DUE TO RN LAYER CAUSE and M1001C80 CS RAB SETUP FAIL DUE TO AC are updated

∆ Prx_nc



• Parameters to change in order to decrease the AC rejection of RAB (or RRC) connection.

• Each BTS measures the total received interference power (PrxTotal)

• BTS uses Alpha Trimmed Averaging Window to calculate Prx_Total values

• BTS reports the PrxTotal results to the RNC by using RADIO RESOURCE INDICATION message every RRIindicationPeriod

• RNC calculates simple arithmetic mean to obtain averaged PrxTotal values

• WinAcRabSetupUl is a BTS parameter that defines the size of the load measurement averaging window used in RNC (AC) to average PrxTotal results

• Sliding averaging window provides new av PrxTotal value every RRI period



• Frame mean of Prx_total is pre-calculated using arithmetic mean of the slot values (15 slots)

• Averaged frames are sorted based on PrxMeasAveWindow frames

• Filtered values are calculated by taking arithmetic frame mean values which are between ALPHA and (1-APLHA) defined by PrxAlpha

• N x α lowest and highest measurements removed• N x (1- 2α) measurements remain

Av. Frame measurements

Prx

• PrxMeasAveWindow = 10 & PrxAlpha = 0.2

• Frame averages are calculated for 10 frames

• 2 max. & 2 min. values excluded : 6 values remaining

• Final average Prx_total is calculated on the 6 values



The BTS is measuring:Prx Total

RADIO RESOURCE INDICATION (RRI) messagePrx Total is reported to the RNC for LC, AC and PS usage, on every RRIindicationperiod (200 ms)

Frame measurements

Prx

BTS uses ALPHA TRIMMED MEAN FILTERPrxAlphaPrxMeasAvWindow

BTS sends the LASTESTaveraged measurement result to RNC every RRI period

RNC is calculating a sliding window averaged value over the values given by RRI messages…

RRIx RRIx+1RRIx+2 RRIx+n

∑=

+⋅=m

jjntotalrx Totalx

mP

1_ _Pr1Sliding window average

result on every RRI periodWinAcRabSetupUI



• Parameter Name: PrxTarget (Prx_target = PrxTarget+PrxNoise)

• Description:An uplink RT RAB is not admitted if the estimated non-controllable power exceeds this threshold

• Default value: 4 dB

The default value is coming from the UL load i.e. 10*LOG(1-η) where η is the loading in %.

The 4dB default value corresponds to 60% loading value

Prx_target

Prx_target_BS

UL interference power

Load

Planned load area

Marginal load area

The value of the The value of the PrxTargetPrxTarget is relative to the system noise; it gives an upper is relative to the system noise; it gives an upper threshold for the noise rise (the ratio of the total received upthreshold for the noise rise (the ratio of the total received uplink power to link power to system noise) => Prx_target = system noise) => Prx_target = PrxTargetPrxTarget++PrxNoisePrxNoise



PrxTarget set too high (compared to dimensioning) -> cell shrinks and there is coverage hole -> RAB establishment fails due to not enough power from UE

Load < PrxTarget

Load => PrxTarget

Load => PrxTarget

PrxTarget set too low (compared to dimensioning) -> RAB establishment requests are denied by AC even though there is "enough" coverage in UL

• In case the value is set too low Admission control can reject RT RAB establishments due to UL load threshold exceeded too early.

• On the other hand in case the value is set too high (higher than used in dimensioning) then the AC will admit new users beyond the planned UL load limit -> cell breathing will cause coverage holes.



• Parameter Name: PrxOffset (Prx_target_BS = PrxTarget + PrxOffset + PrxNoise)

• Description: The target value of the total received power (PrxTarget) can be exceeded by the value of this parameter before the cell is considered to be overloaded in uplink

• Default value: 1 dB

The default value of this and PrxTarget gives the total noise rise as 4dB + 1dB = 5dB which corresponds to 68% load

PrxTarget + PrxOffset [dB] should be set according to dimensioning e.g. in case in dimensioning the UL load has been set to be 50% (including RT and NRT services) then the PrxTarget+ PrxOffset [dB] should be set to 3dB

PrxTarget + PrxOffset [dB] should be set according to dimensioning e.g. in case in dimensioning the UL load has been set to be 50% (including RT and NRT services) then the PrxTarget+ PrxOffset [dB] should be set to 3dB




• Together with the DL admission decision equation the maximum allowed DL transmission power per connection limits the coverage (and capacity) of certain user (using certain service)

• The maximum DL transmission power per connection is determined by the parameter CPICHToRefRABOffset and the formula belowfRabOffsetpichToC Re

CPICH coverage

PtxPrimaryCPICH

=Service Coverage

abOffsetpichtorefR

CPICHtx

refreftx C

PRI

RIP ,maxmax, ⋅

⋅⋅

=ρρ

CPICHtxP ,

The formula for the maximum link power isdefined so that the CPICH coverage and the service coverage are ALWAYS the same




• Ptx_target = max planned DL tx power• Set by RNP parameter PtxTarget• When the NC cell load exceeds the target

limit, AC rejects RAB requests that would mean immediate DL load increase (i.e. RT RABs)

Ptx_target

Ptx_target_BS

DL transmission power

Load

Planned load area

Marginal load area

• Ptx_target_BS = DL overload threshold above which BTS starts its load control actions to prevent overload

• RNC also performs preventive actions; AC rejects all RAB requests if this limit is reached

• Ptx_target_BS is defined by the RNP parameters PtxOffset + PtxTarget




Assignment Request

RAB Establishment



In case the DL load (measured PtxTotal) exceeds PtxTraget + PtxOffset or Ptx_nc + ∆ Ptx_nc exceeds PtxTarget

Counter M1002C14 RT DCH REQ FOR CS VOICE CALL REJECT IN DL IN SRNC is updated – includes SHOM1002C17 RT DCH DHO REQ FOR CS VOICE CALL REJECT IN SRNC – includes SHO only

Same separately for:CS Conversational classCS Streaming classPS Conversational classPS Streaming classPS Interactive classPS Background class


inactivetxtxnctx PPP ,_ +∆=∆

reftxefftxtx PRIPP ,max,max, ⋅==∆


In case the RAB assignment fails due to AC, counters:M1003C13 RAB ASS NONSUCC DUE TO RN LAYER CAUSE and M1001C80 CS RAB SETUP FAIL DUE TO AC are updated refref

eff RIRIRI⋅⋅

=ρρ max

max,fRabOffsetpichTo

CPICHtxreftx C

PP

Re

,, =



ALCAP:ERQ

NBAP: RL Reconfiguration Prepare

NBAP: RL Reconfiguration Ready


Assignment Request

ALCAP:ECF

RAB Establishment



In case successful AC (UL and DL) counter M1002C18 -M1002C33 RT DCH ALLO FOR AMR x.xx KBPS IN yL IN SRNCFor different bitrates and separately for UL and DL, includes SHO as well

Same separately for:CS Conversational classCS Streaming classPS Conversational classPS Streaming classPS Interactive classPS Background classNBAP: RL Reconfiguration Commit

[DCH] RRC: Radio Bearer Setup

[DCH] RRC: Radio Bearer Setup Complete







NBAP: RL Reconfiguration Failure


Assignment Request


UE Node B RNC MGWWhen RNC starts existing RL modification procedure (to modify the RL set up for SRB) counter:M1005C79 RL RECONF PREP SYNCH FOR DCH MOD ON SRNC

In case there is a failure to setup RL with the BTS one of the failure cause counters is updated:M1005C96 RL RECONF PREP SYNCH FOR DCH MOD FAIL ON SRNC DUE TO O&M INTERVM1005C97 RL RECONF PREP SYNCH FOR DCH MOD FAIL ON SRNC DUE TO ALREADY ACTIVM1005C98 RL RECONF PREP SYNCH FOR DCH MOD FAIL ON SRNC DUE TO HW RES NOT AVAILM1005C99 RL RECONF PREP SYNCH FOR DCH MOD FAIL ON SRNC DUE TO NOT ENOUGH RESM1005C100 RL RECONF PREP SYNCH FOR DCH MOD FAIL ON SRNC DUE TO BTS NOT RESPM1005C101 RL RECONF PREP SYNCH FOR DCH MOD FAIL ON SRNC DUE TO BTS GEN REA

In case the RAB assignment fails due to AC, counters:M1003C13 RAB ASS NONSUCC DUE TO RN LAYER CAUSE and M1001C81 CS RAB SETUP FAIL DUE TO BTS are updated




ALCAP:ERQ




Assignment Request

ALCAP:ECF


NBAP: RL Reconfiguration Cancel

UE Node B RNC MGWWhen RNC starts existing RL modification procedure (to modify the RL set up for SRB) counter:M1005C79 RL RECONF PREP SYNCH FOR DCH MOD ON SRNC

In case of Successful RL Reconfiguration counter:M1005C85 RL RECONF PREP SYNCH FOR DCH MOD ON SRNC READY, is updated

In case the AAL2 connection setup fails , counters:M1003C14 RAB ASS NONSUCC DUE TO TR LAYER CAUSE and M1001C82 CS RAB SETUP FAIL DUE TO TRANSM are updated

In case the AAL2 connection setup fails , NBAP RL Reconfiguration Cancel message is sent and counter: M1005C128 RL RECONF CANC SYNCH ON SRNC DUE TO TRANSMISSION SETUP FAILis updated

In case the RAB assignment fails due to AC, counters:M1003C13 RAB ASS NONSUCC DUE TO RN LAYER CAUSE and M1001C81 CS RAB SETUP FAIL DUE TO BTS are updated




ALCAP:ERQ




Assignment Request

ALCAP:ECF

NBAP: RL Reconfiguration Commit



UE Node B RNC MGW

Successful AAL2 setup leads to NBAP: RL Reconfiguration Commit message being sent to the BTS and counterM1005C126 RL RECONF COMM SYNCH ON SRNC – includes modifications & additions

After successful RL Reconfiguration Commit the RNC tells the UE about the new DCH by sending RRC: Radio Bearer Setup message. Counter:M1006C28 RADIO BEARER SETUP is updated

THIS IS THE END OF RAB SETUP PHASE and THIS IS THE END OF RAB SETUP PHASE and STARTING POINT OF RAB ACCESS PHASE STARTING POINT OF RAB ACCESS PHASE

In case there is no RRC: Radio Bearer Setup Complete message received from the UE either counter M1001C122 RAB SETUP ACC FAIL FOR CS VOICE CALL DUE TO UE (UE failing to support new configuration) or M1001C123 RAB SETUP ACC FAIL FOR CS VOICE CALL DUE TO RNC INTERNAL is updated (the RB Setup Complete message is lost)




ALCAP:ERQ




Assignment Request

ALCAP:ECF

NBAP: RL Reconfiguration Commit


[DCH] RRC: Radio Bearer Setup Complete


UE Node B RNC MGW

In case of successful RAB Assignment counters:M1003C11 RAB ASS SUCC and M1001C115RAB SETUP ACC COMP FOR CS VOICE CALL are updated

THIS IS THE END OF RAB ACCESS PHASETHIS IS THE END OF RAB ACCESS PHASE


Handovers Handovers; SHO, ISHO, IFHO

Decision toset up new RL

RRC: Measurement Report (e1a / e1c)

NBAP: Radio Link Setup Response

Start TX/RX

ALCAP:ERQ

ALCAP:ECF

RRC: Active Set Update Complete

UE Received message RRC: Measurement Report (e1A). Triggers for RT:M1007C10 CELL ADDITION REQUEST ON SHO FOR RT TRAFFICReceived message RRC: Measurement Report (e1B). Triggers for RT:M1007C11 CELL DELETION REQUEST ON SHO FOR RT TRAFFICReceived message RRC: Measurement Report (e1C). Triggers for RT:M1007C12 CELL REPLACEMENT REQUEST ON SHO FOR RT TRAFFICReceived message RRC: Measurement Report (e1A). Triggers for NRT:M1007C27 CELL ADDITION REQUEST ON SHO FOR NRT TRAFFICReceived message RRC: Measurement Report (e1B). Triggers for NRT:M1007C28 CELL DELETION REQUEST ON SHO FOR NRT TRAFFICReceived message RRC: Measurement Report (e1C). Triggers for NRT:M1007C29 CELL REPLACEMENT REQUEST ON SHO FOR NRT TRAFFIC

A

B

NBAP: Radio Link Addition Request – for So over

NBAP: Radio Link Addition Response

BTS RNC

fter Hand

NBAP: Radio Link Setup Request – for Soft HandoverNBAP: Radio Link Setup Request – for Soft Handover

For each cell already in AS the above counters are updated i.e. in this case 2 cellsRRC: Active Set Update

At first (UE in point A) AS includes 2 cells Then UE moves to point B and reports e1A to add “blue” cell



RNC

Decision to set up new RL


NBAP: Radio Link Setup Request


Start TX/RX

ALCAP:ERQ

ALCAP:ECF


UL Synchronisation Procedure starts

UE Synchronisation Procedure starts: According to Synchronization Procedure B

NBAP: Synchronization Indication

Number of DCH requests for Diversity HO (SHO) for voice calls in SRNCM1002C16 RT DCH DHO REQ FOR CS VOICE CALL IN SRNCNumber of DCH requests for a CS Voice Call rejected by the SRNC for reasons caused by radio resources in the target cell of diversity handoverM1002C17 RT DCH DHO REQ FOR CS VOICE CALL REJECT IN SRNCNumber of DCH requests for a transparent CS Data Call with conversational class due to diversity handover in the SRNCM1002C58 RT DCH DHO REQ FOR CS DATA CALL CONV CLASS IN SRNCNumber of DCH requests for a transparent CS Data Call (on SRNC side) rejected for reasons caused by radio resources in the target cell of diversity handoverM1002C59 RT DCH DHO REQ FOR CS DATA CALL CONV CLASS REJECT IN SRNCSRNC A total number of DCH requests for a nontransparent CS DataCall with streaming class due to diversity handover in the SRNCM1002C60 RT DCH DHO REQ FOR CS DATA CALL STREAM CLASS INNumber of DCH requests for a nontransparent CS Data Call with streaming class (SRNC side) rejected for reasons caused by radioresources in the target cell of diversity handoverM1002C61RT DCH DHO REQ FOR CS DATA CALL STREAM CLASS REJECT IN SRNCSAME FOR DRNC!

In case of RNC sends to BTS NBAP: RL Setup Request/RL Addition RequestM1005C1: RL SETUP ATT FOR SHO ON SRNCM1005C3:RL SETUP ATT FOR SHO ON DRNCM1005C42: RL BRANCH ADD ATT FOR SHO ON SRNCM1005C43: RL BRANCH ADD ATT FOR SHO ON DRNC

In case BTS responses back to RNC by NBAP: RL Setup Response/RL Addition ResponseM1005C6: RL SETUP SUCC FOR SHO ON SRNCM1005C8:RL SETUP SUCC FOR SHO ON DRNCM1005C44: RL BRANCH ADD SUCC FOR SHO ON SRNCM1005C45: RL BRANCH ADD SUCC FOR SHO ON SRNC

BTSUE

RRC: Active Set Update



Decision toset up new RL



Start TX/RX

ALCAP:ERQ

ALCAP:ECF

RRC: Active Set Update CompleteRRC: Active Set Update Failure

BTS RNCUEReceived message RRC: Active Set Update Complete. Triggers:M1007C15 SUCCESSFUL ACTIVE SET UPDATES ON SHO FOR RT TRAFFICReceived message RRC: Active Set Update Complete. Triggers:M1007C32 SUCCESSFUL ACTIVE SET UPDATES ON SHO FOR NRT TRAFFIC



For each cell in the AS the above counter(s) are updated (including the cell to be deleted from AS in case of e1B)

Received message RRC: Active Set Update Failure. Triggers: M1007C16 UNSUCCESSFUL ACTIVE SET UPDATES ON SHO FOR RT TRAFFICReceived message RRC: Active Set Update Failure. Triggers:M1007C33 UNSUCCESSFUL ACTIVE SET UPDATES ON SHO FOR NRT TRAFFIC



1

2

A

UE is in Spot A i.e. not in soft handover -> AS size = 1

UE in Spot B sends Measurement report indicating e1A to add cell 2 -> M1007C10 CELL ADDITION REQUEST ON SHO FOR RT TRAFFIC is updated in cell 1

RNCBTS


UE

1

2B


RNC sends NBAP: RL Setup Request to BTS –updates M1005C1: RL SETUP ATT FOR SHO ON SRNC counter in cell 2

RNC Makes AC/RM for the SHO – updates M1002C16 RT DCH DHO REQ FOR CS VOICE CALL IN SRNC counter in cell 2



ALCAP:ERQ

ALCAP:ECF

UL SynchronisationProcedure starts

BTS receives the NBAP; RL Setup Request, if RL Setup Is successful, starts TX/RX and UL Synchronization procedure and sends NBAP: RL Setup Response to RNC

Start TX/RX




RNC Sends RRC: Active Set Update –message to the UE

1

2B

When receiving RRC: Active Set Update Complete, the RNC updates M1007C15 SUCCESSFUL ACTIVE SET UPDATES ON SHO FOR RT TRAFFIC or M1007C32 SUCCESSFUL ACTIVE SET UPDATES ON SHO FOR NRT TRAFFIC counter. Counter updated for cell 1.

RNCBTS


UE




ALCAP:ERQ

ALCAP:ECF

UL SynchronisationProcedure startsStart TX/RX


After receiving RRC: Active Set Update from RNC the UE checks the Update message and if ok UE starts Synchronization Procedure B and and sends RRC: Active Set Update Complete message without waiting for the completion of the Physical Layer synchronization procedure B(according to 25.214/25.331)




• The Active Set Update success rate can be calculated as:

%

))161007()151007(())151007((*100)(

CMTrafficRTForSHOOnUpdatesSetActiveulUnsuccessfCMTrafficRTForSHOOnUpdatesSetActiveSuccessfulsumCMTrafficRTForSHOOnUpdatesSetActiveSuccessfulsumRTRatioSuccessUpdateSetActive

+=

%

))331007()321007(())321007((*100)(

CMTrafficNRTForSHOOnUpdatesSetActiveulUnsuccessfCMTrafficNRTForSHOOnUpdatesSetActiveSuccessfulsumCMTrafficNRTForSHOOnUpdatesSetActiveSuccessfulsumNRTRatioSuccessUpdateSetActive

+=


RNCBTS


UE




ALCAP:ERQ

ALCAP:ECF




1



RNCBTS


UE




ALCAP:ERQ

ALCAP:ECF




• In case also RL Setup Procedure and AC decision are needed to be included then the SHO Success Rate could be counted as:

• (M1007C15)/(M1007C10 + M1007C11 + M1007C12) – for RT traffic• (M1007C32)/(M1007C27 + M1007C28 + M1007C29) – for NRT traffic

• SUCCESSFUL ACTIVE SET UPDATES ON SHO FOR RT TRAFFIC (M1007C15) divided by ADDITION/DELETION/REPLACEMENT REQUEST ON SHO FOR RT TRAFFIC (M1007C10 + M1007C11 + M1007C12)

2

%M1005C8M1005C6M1005C45M1005C44M1005C3M1005C1 M1005C43 M1005C42*100

)(/

++++++=SHOSuccessAdditionUpSetLinkRadio

• And separate failure reasons can be identified based on M1005C16 – M1005C21, M1005C28 – M1005C33, M1005C46 –M1005C57 and M1005C58 – M1005C65

• Then in case the SHO Success Rate formula 1 and 2 are giving different results the problem spot can be identified by analysing:

• Iub Radio Link Set up & Addition success rate (either combined as below or separately)


Handovers



• Then in case the SHO Success Rate formula 1 and 2 are giving different results the problem spot can be identified by analysing:

• DCH allocation success rate for SHO purposes


RNCBTS


UE




ALCAP:ERQ

ALCAP:ECF




%100M1002C108M1002C106M1002C104M1002C102M1002C60M1002C58M1002C16

10910021071002105100210310026110025910021710021

)(

⋅

++++++++++++

−

=

CMCMCMCMCMCMCMSHOSuccessAllocationDCH

• Where nominator is stating the number of DCH allocation requests in the target cellfor Diversity Handover (SHO) for RT traffic classes (Speech+Conversational CS data + Streaming CS Data) and NRT traffic classes (Conversational PS data + Streaming PS data + Interactive PS data + Background PS data)

• Where denominator is the allocation rejections due to lack of radio resources in target cell


Handovers• RL SETUP ATT FOR SHO ON SRNC (M1005C1)

• A number of radio link setup attempts for soft HO on SRNC side• UPDATED when a common NBAP signaling entity sends a RADIO_LINK_SETUP_REQUEST

message to a BTS

• RL SETUP ATT FOR SHO ON DRNC (M1005C3)• A number of radio link setup attempts for soft HO on DRNC side• UPDATED when a common NBAP signaling entity sends a RADIO_LINK_SETUP_REQUEST

message to a BTS

• RL SETUP SUCC FOR SHO ON SRNC (M1005C6)• A number of radio link setup successes for SHO (=first RL)• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_RESPONSE

message from a BTS

• RL SETUP SUCC FOR SHO ON DRNC (M1005C8)• A number of radio link setup successes for SHO (=first RL)• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_RESPONSE

message from a BTS

• RL SETUP FAIL FOR SHO ON SRNC DUE TO O&M INTERV (M1005C16)• A number of radio link setup failures for soft HO on SRNC side due to O&M intervention• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE

message from a BTS



Handovers• RL SETUP FAIL FOR SHO ON SRNC DUE TO ALREADY ACTIV (M1005C17)

• A number of radio link setup failures for soft HO on SRNC side due to a context that is already activated

• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE message from a BTS

• RL SETUP FAIL FOR SHO ON SRNC DUE TO HW RES NOT AVAIL (M1005C18)• A number of radio link setup failures for soft HO on SRNC side caused by the fact that there

are no available HW resources• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE

message from a BTS

• RL SETUP FAIL FOR SHO ON SRNC DUE TO NOT ENOUGH RES (M1005C19)• A number of radio link setup failures for soft HO on SRNC side caused by the fact that there

are not enough resources• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE

message from a BTS

• RL SETUP FAIL FOR SHO ON SRNC DUE TO BTS NOT RESP (M1005C20)• A number of radio link setup failures for soft HO on SRNC side caused by the fact that the BTS

is not responding• If the BTS does not respond in the allowed time• UPDATED when a common NBAP signaling entity does not receive any response from a BTS

to a RADIO_LINK_SETUP message



Handovers• RL SETUP FAIL FOR SHO ON SRNC DUE TO BTS GEN REA (M1005C21)

• A number of radio link setup failures for soft HO on SRNC side due to a general reason of a BTS• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE

message from a BTS

• RL SETUP FAIL FOR SHO ON DRNC DUE TO O&M INTERV (M1005C28)• A number of radio link setup failures for soft HO on DRNC side due to O&M intervention• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE

message from a BTS

• RL SETUP FAIL FOR SHO ON DRNC DUE TO ALREADY ACTIV (M1005C29)• A number of radio link setup failures for soft HO on DRNC side due to a context that is already

activated• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE

message from a BTS

• RL SETUP FAIL FOR SHO ON DRNC DUE TO HW RES NOT AVAIL (M1005C30)• A number of radio link setup failures for soft HO on DRNC side caused by the fact that there are

no available HW resources• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE

message from a BTS

• RL SETUP FAIL FOR SHO ON DRNC DUE TO NOT ENOUGH RES (M1005C31)• A number of radio link setup failures for soft HO on DRNC side caused by the fact that there are

not enough resources• UPDATED when a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE

message from a BTS



Handovers• RL SETUP FAIL FOR SHO ON DRNC DUE TO BTS NOT RESP (M1005C32)

• A number of radio link setup failures for soft HO on DRNC side caused by the fact that the BTS is not responding

• If the BTS does not respond in the allowed time• UPDATED when a common NBAP signaling entity does not receive any response from a BTS

to a RADIO_LINK_SETUP message

• RL SETUP FAIL FOR SHO ON DRNC DUE TO BTS GEN REA (M1005C33)• A number of radio link setup failures for soft HO on DRNC side due to a general reason

caused by a BTS• UPDATED: When a common NBAP signaling entity receives a RADIO_LINK_SETUP_FAILURE

message from a BTS



• RL BRANCH ADD FAIL FOR SHO ON SRNC DUE TO O&M INTERV (M1005C46)• A number of radio link branch addition failures for softer HO on SRNC side due to O&M

intervention• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_ADDITION_ FAILURE

message from a BTS

• RL BRANCH ADD FAIL FOR SHO ON SRNC DUE TO ALREADY ACTIV (M1005C47)• A number of radio link branch addition failures for softer HO on SRNC side due to a context that

is already activated• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_ADDITION_ FAILURE

message from a BTS

• RL BRANCH ADD FAIL FOR SHO ON SRNC DUE TO HW RES NOT AVAIL (M1005C48)• A number of radio link branch addition failures for softer HO on SRNC caused by the fact that

there are no resources available• UPDATED when a Dedicated NBAP signaling entity receives a RADIO_LINK_ADDITION_FAILURE

message from a BTS

• RL BRANCH ADD FAIL FOR SHO ON SRNC DUE TO NOT ENOUGH RES (M1005C49)• A number of radio link branch addition failures for softer HO on SRNC side caused by the fact

that there are not enough resources• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_ADDITION_ FAILURE

message from a BTS

• RL BRANCH ADD FAIL FOR SHO ON SRNC DUE TO BTS NOT RESP (M1005C50)• A number of radio link branch addition failures for softer HO on SRNC side caused by the fact

that a BTS is not responding• If the BTS does not respond in the allowed time• UPDATED when a dedicated NBAP signaling entity does not receive any response from a BTS to

a RADIO_LINK_ADDITION_REQUEST message


Handovers


Handovers• RL BRANCH ADD FAIL FOR SHO ON SRNC DUE TO BTS GEN REA (M1005C51)

• A number of radio link branch addition failures for softer HO on SRNC side due to a general BTS reason

• UPDATED when a Dedicated NBAP signaling entity receives a RADIO_LINK_ADDITION_FAILURE message from a BTS

• RL BRANCH ADD FAIL FOR SHO ON DRNC DUE TO O&M INTERV (M1005C52)• A number of radio link branch addition failures for softer HO on DRNC side due to O&M

intervention• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_ADDITION_ FAILURE

message from a BTS

• RL BRANCH ADD FAIL FOR SHO ON DRNC DUE TO ALREADY ACTIV (M1005C53)• A number of radio link branch addition failures for softer HO on DRNC side due to a context

that is already activated• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_ADDITION_ FAILURE

message from a BTS

• RL BRANCH ADD FAIL FOR SHO ON DRNC DUE TO HW RES NOT AVAIL (M1005C54)• A number of radio link branch addition failures for softer HO on DRNC side due to 'HW

resource not available'• UPDATED: When a dedicated NBAP signaling entity receives a

RADIO_LINK_ADDITION_FAILURE message from a BTS



Handovers• RL BRANCH ADD FAIL FOR SHO ON DRNC DUE TO NOT ENOUGH RES (M1005C55)

• A number of radio link branch addition failures for softer HO on DRNC side due to 'not enough resources'

• UPDATED: When a dedicated NBAP signaling entity receives a RADIO_LINK_ADDITION_ FAILURE message from a BTS

• RL BRANCH ADD FAIL FOR SHO ON DRNC DUE TO BTS NOT RESP (M1005C56)• A number of radio link branch addition failures for softer HO on DRNC side caused by the fact

that a BTS is not responding• UPDATED when a dedicated NBAP signaling entity does not receive any response from a BTS

to a RADIO_LINK_ADDITION_REQUEST message

• RL BRANCH ADD FAIL FOR SHO ON DRNC DUE TO BTS GEN REA (M1005C57)• A number of radio link branch addition failures for softer HO on DRNC side due to a general

BTS reason• UPDATED: When a dedicated NBAP signaling entity receives a

RADIO_LINK_ADDITION_FAILURE message from a BTS



Handovers• Also it is very useful to check the synchronization failures for the SHO cases (RL failures

due to synchronization)• RL FAIL ON SRNC DUE TO INI SYN FAIL (M1005C58)

• A number of radio link failures on SRNC side caused by an initial synchronisation failure• If a BTS fails to establish synchronisation at L1 during the allowed time• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_FAILURE

message from a BTS• RL FAIL ON SRNC DUE TO ACT RL SYN FAIL (M1005C59)

• A number of radio link failures on SRNC side caused by an active radio link synchronisation failure

• If a BTS loses synchronisation on an active RL and is not able to re-establish synchronisation during the allowed time.

• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_FAILURE message from a BTS

• RL FAIL ON DRNC DUE TO INI SYN FAIL (M1005C62)• A number of radio link failures on DRNC side caused by an initial synchronisation

failure.• If a BTS fails to establish synchronisation at L1 during the allowed time• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_FAILURE

message from a BTS• RL FAILURE ON DRNC DUE TO ACT RL SYN FAIL (M1005C63)

• A number of radio link failures on DRNC side caused by an active radio link synchronisation failure

• If a BTS loses synchronisation on an active RL and is not able to re-establish synchronisation during the allowed time

• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_FAILURE message from a BTS



Handovers• RL FAIL ON SRNC DUE TO BTS HW OVERL (M1005C60)

• A number of radio link failures on SRNC side caused by a BTS HW overload• If a BTS reports on a HW overload.• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_FAILURE message

from a BTS

• RL FAIL ON SRNC DUE TO BTS EQUIP FAIL (M1005C61)• A number of radio link failures on SRNC side due to a BTS equipment failure• If a BTS reports on an equipment failure• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_FAILURE message

from a BTS

• RL FAIL ON DRNC DUE TO BTS HW OVERL (M1005C64)• A number of radio link failures on DRNC side caused by a BTS HW overload• If a BTS reports on a HW overload• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_FAILURE message

from a BTS

• RL FAIL ON DRNC DUE TO BTS EQUIP FAIL (M1005C65)• A number of radio link failures on DRNC side caused by a BTS equipment failure• If a BTS reports on an equipment failure• UPDATED when a dedicated NBAP signaling entity receives a RADIO_LINK_FAILURE message

from a BTS



Handovers• RL DEL ON SRNC DUE TO INI SYN FAIL (M1005C67)

• When a RADIO_LINK_DELETION_REQUEST message is sent to a BTS.• A number of radio link deletions on SRNC side due to an initial synchronisation failure• If a BTS fails to establish synchronisation at L1 during the allowed time• UPDATED when a dedicated NBAP signaling entity sends a RADIO_LINK_DELETION_REQUEST

message to a BTS

• RL DEL ON SRNC DUE TO ACT RL SYN FAIL (M1005C68)• A number of radio link deletions on SRNC side due to an active radio link synchronisation

failure• If a BTS loses synchronisation on an active RL and is not able to re-establish synchronisation

during the allowed time• UPDATED when a dedicated NBAP signaling entity sends a RADIO_LINK_DELETION_REQUEST

message to a BTS

• RL DEL ON SRNC DUE TO BTS HW OVERL (M1005C69)• A number of radio link deletions on SRNC side due to a BTS HW overload• If a BTS reports on a HW overload• UPDATED when a dedicated NBAP signaling entity sends a RADIO_LINK_DELETION_REQUEST

message to a BTS

• RL DEL ON SRNC DUE TO BTS EQUIP FAIL (M1005C70)• A number of radio link deletions on SRNC side due to a BTS equipment failure• If a BTS reports on an equipment failure• UPDATED when a dedicated NBAP signaling entity sends a RADIO_LINK_DELETION_REQUEST

message to a BTS



Handovers• RL DEL ON DRNC DUE TO INI SYN FAIL (M1005C73)

• A number of radio link deletions on DRNC side due to an initial synchronisation failure• If a BTS fails to establish synchronisation at L1 during the allowed time• UPDATED when a dedicated NBAP signaling entity sends a RADIO_LINK_DELETION_REQUEST

message to a BTS

• RL DEL ON DRNC DUE TO ACT RL SYN FAIL (M1005C74)• A number of radio link deletions on DRNC side due to an active radio link synchronisation

failure• If a BTS loses synchronisation on an active RL and is not able to re-establish synchronisation

during the allowed time• UPDATED when a dedicated NBAP signaling entity sends a RADIO_LINK_DELETION_REQUEST

message to a BTS

• RL DEL ON DRNC DUE TO BTS HW OVERL (M1005C75)• A number of radio link deletions on DRNC side due to BTS HW overload• If a BTS reports on a HW overload• UPDATED when a dedicated NBAP signaling entity sends a RADIO_LINK_DELETION_REQUEST

message to a BTS

• RL DEL ON DRNC DUE TO BTS EQUIP FAIL (M1005C76)• A number of radio link deletions on DRNC side due to a BTS equipment failure• If a BTS reports on an equipment failure• UPDATED when a dedicated NBAP signaling entity sends a RADIO_LINK_DELETION_REQUEST

message to a BTS




• SHO overhead per cell (does not apply for areas of several cells) can be calculated as:

%100*)1

)M1007C21)(M1007C2)(M1007C20)(M1007C1)(

M1007C19)(M1007C0)((3*)M1007C21)(M1007C2)((

2*)M1007C20)(M1007C1)((1*)M1007C19)(M1007C0)((

( −

++++

+++

+++

=

NRTforsetactivetheincellThreeRTforsetactivetheincellThreeNRTforsetactivetheincellTwoRTforsetactivetheincellTwo

NRTforsetactivetheincellOneRTforsetactivetheincellOnesumNRTforsetactivetheincellThreeRTforsetactivetheincellThreesum

NRTforsetactivetheincellTwoRTforsetactivetheincellTwosumNRTforsetactivetheincellOneRTforsetactivetheincellOnesum

overheadSHO


HandoversReporting nt Ec/No is triggered etc. triggered

: COMPRESSED MODE COMMAND

: RADIO LINK RECONFIGURATION PREPARE

: RADIO LINK RECONFIGURATION READY

: RADIO LINK RECONFIGURATION COMMIT

TRANSPORT CHANNEL RECONFIGURATION

RRC: TRANSPORT CHANNEL GURATION COMPLETE

Handover desicion. BSIC verification required

•M1010 C3 NBR OF STARTED INTER SYST HHO MEAS WITH COM MOD DUE TO UL DCH QUAL FOR RT•M1010 C4 NBR OF STARTED INTER SYST HHO MEAS WITH COM MOD DUE TO UE TX PWR FOR RT•M1010 C5 NBR OF STARTED INTER SYST HHO MEAS WITH COM MOD DUE TO DL DPCH FOR RT•M1010 C6 NBR OF STARTED INTER SYST HHO MEAS WITH COM MOD DUE TO CPICH RSCP FOR RT•M1010 C7 NBR OF STARTED INTER SYST HHO MEAS WITH COM MOD DUE TO CPICH ECNO FOR RT

•M1010C18 INTER SYST HHO ATTEMPTS CAUSED BY UL DCH QUAL FOR RT•M1010C22 INTER SYST HHO ATTEMPTS CAUSED BY UE TX PWR FOR RT•M1010C26 INTER SYST HHO ATTEMPTS CAUSED BY DL DPCH PWR FOR RT•M1010C30 INTER SYST HHO ATTEMPTS CAUSED BY CPICH RSCP FOR RT•M1010C34 INTER SYST HHO ATTEMPTS CAUSED BY CPICH ECNO FOR RT


eve

NBAP

NBAP

NBAP

NBAP

RRC:

RECONFI

BTS1 RNC MSCUE

RRC: MEASUREMENT REPORT (event 1F)

Decision to activate inter-RAT measurement.Determination of CM pattern.

RRC: MEASUREMENT CONTROL

RRC: MEASUREMENT REPORT (GSM RSSI, BCCH ARFCN)

RRC:MEASUREMENT REPORT (GSM RSSI, BCCH ARFCN)

NBAP: COMPRESSED MODE COMMAND (CFN, TGPSI 3)

RRC: MEASUREMENT CONTROL (BSIC,CFN,TGPSI 3)

RANAP: RELOCATION REQUIRED

RANAP: RELOCATION COMMAND

•M1009C235 INTER SYST HHO OUT PREP REQ CONTR BY MSC

RRC: MEASUREMENT REPORT (BSIC, GSM cell index)

RRC: HANDOVER FROM UTRAN COMMAND

RANAP: IU RELEASE COMMAND

RANAP: IU RELEASE COMPLETENBAP: RADIO LINK DELETION REQUEST

NBAP: RADIO LINK DELETION RESPONSE



Reporting nt Ec/No is triggered etc. triggered

RANAP: RELOCATION REQUIRED

RANAP: RELOCATION COMMAND

RANAP: IU RELEASE COMMAND

: COMPRESSED MODE COMMAND (CFN, TGPSI 3)

MEASUREMENT CONTROL (BSIC,CFN,TGPSI 3)

RRC: MEASUREMENT REPORT cell index)

HANDOVER FROM UTRAN COMMAND

: RADIO LINK RECONFIGURATION COMMIT

TRANSPORT CHANNEL RECONFIGURATION

RRC: TRANSPORT CHANNEL GURATION COMPLETE

RRC:MEASUREMENT REPORT SI, BCCH ARFCN)

Handover desicion. BS verification required

•M1009C236 INTER SYST HHO OUT PREP SUCC CONTR BY MSC

•M1006C63 HO FROM UTRAN COM

•M1010C19 SUCCESSFUL INTER SYST HARD HANDOVRS CAUSED BY UL DCH QUAL FOR RT•M1010C22 INTER SYST HHO ATTEMPTS CAUSED BY UE TX PWR FOR RT•M1010C26 INTER SYST HHO ATTEMPTS CAUSED BY DL DPCH PWR FOR RT•M1010C30 INTER SYST HHO ATTEMPTS CAUSED BY CPICH RSCP FOR RT•M1010C34 INTER SYST HHO ATTEMPTS CAUSED BY CPICH ECNO FOR RT

eve

NBAP

RRC:

(BSIC, GSM

RRC:

NBAP

RRC:

RECONFI

(GSM RS

BTS1 RNC MSCUE

RRC: MEASUREMENT REPORT (event 1F)

NBAP: COMPRESSED MODE COMMAND

RANAP: IU RELEASE COMPLETE

RRC: MEASUREMENT CONTROL

RRC: MEASUREMENT REPORT (GSM RSSI, BCCH ARFCN)

NBAP: RADIO LINK DELETION REQUEST

NBAP: RADIO LINK DELETION RESPONSE

NBAP: RADIO LINK RECONFIGURATION PREPARE

NBAP: RADIO LINK RECONFIGURATION READY

IC

Decision to activate inter-RAT measurement.Determination of CM pattern.



GSM900

WCDMA Continuous coverage for each layer: GSM900, GSM1800 and WCDMA

Continuous coverage for: GSM900 and GSM1800 and no WCDMA coverage (typically indoor)GSM1800

Continuous coverage for GSM900 and GSM1800 layers. For WCDMA coverage holes exist (even outdoor)

Continuous coverage for GSM900 and GSM1800 layers. Coverage border for WCDMA



• UE camps in a 3G cell• If UE moves out of 3G service area (or enters a 3G “hole”) it starts 2G

neighbor measurements when CPICH Ec/N0 < Qqualmin + SsearchRAT (-18dB +4dB = -14 dB)

• UE reselects to a 2G cell ifRXLEV > CPICH RSCP + Qhyst1 and RXLEV > AdjgQrxlevminRXLEV > CPICH RSCP + 2 dB and RXLEV > -95 dBm

• And the above criteria are met for 5 consecutive seconds.



• UE camps in a 2G cell• UE measures 3G neighbors all the time (if neighbors defined)

• Threshold to search WCDMA RAN cells (QSRI) = 7• GPRS Threshold to search WCDMA RAN cells (QSRP) = 7

• When UE enters 3G service area it re-selects to 3G cell if• CPICH RSCP > RXLEV + FDD and b) CPICH Ec/No >= FDM• CPICH RSCP > RXLEV + -Infinity and b) CPICH Ec/No > = -13 dB• CPICH RSCP > -Infinity and b) CPICH Ec/No >= -13 dB

• And the above criteria are met for 5 consecutive seconds (3GPP TS 05.08)



Note: No ISHO defined between WCDMA and GSM1800

GSM1800

GSM900

WCDMATwo-Way neighborOne-Way neighbor• For every WCDMA Cell, 2-4 outgoing GSM G9 neighbours are

to be defined based on the predicted overlapping areas• These GSM neighbours need not necessary be from the

same site as the WCDMA cell

• During drive test measurements, additional GSM neighbours might need to be added in places where there is no WCDMA coverage


Handovers• On the 3G coverage border:

• Cell re-selection quantity CPICH Ec/No is not fading so fast outside the real 3G service area

• This would mean that very many (up to 5th tier) neighbours should be defined

• To avoid excessive number of 2G neighbours, 2G measurements are started already at CPICH Ec/No = -10 dB

• This aggressive set-up would introduce a high inter-RAT ping-ponging risk -> neighbour plan based hysteresis is introduced


If required.



• The number of WCDMA neighbours to be defined for the GSM cells will depend on

• How aggressive we want the UE to re-select back to the WCDMA network and

• is there any impact on GSM neighbour measurement as more WCDMA neighbours are defined

• A Nokia WCDMA cell may have up-to 32 GSM neighbors defined



• 3G to 2G ISHOs are enabled for • AMR 12.2 conversational class voice calls• Multi-RAB, one AMR voice + one PS data

• Possible service downgrade with PS data• Whilst AMR call is on-going the PS data transfer is suspended on

2G side.

• 3G to 2G CCO is enabled for • PS domain services• Service downgrade in 2G GPRS



• The triggers for ISHO are:• CPICH Ec/NO, CPICH RSCP • Not enabled: UE Tx Power, UL Quality, DL Quality

CPICH Ec/No

HHO CPICH RSCP Threshold = -95 dBm (Cancel: -90 dBm)

CPICH RSCP

HHO CPICH Ecno Threshold = -13 dB (Cancel: -12 dB)

Measurement report

RXLEV

-95 dBm

Note:FMCS group parameters are common for ISHO and IFHO



• To guarantee seamless service and to avoid excessive number of 2G neighbors special settings are required:

• Cell re-selection• SSearchRAT = 6 dB (-16 + 6 = -10; start 2G measurements when

CPICH Ec/No <-10dB)• AdjgQoffset1 = 0 dB (GSM cell has to be stronger than WCDMA cell)• AdjgQrxlevmin = -95 dBm (minimum criteria for GSM rxlevmin to

reselect to)• Pay attention to 2G neighbor definitions.

• Handovers• HHOEcnoThreshold/Cancel -13 dB/-12 dB• HHORSCPThreshold/Cancel -95 dBm/ -90 dBm• AdjqRxlevMinHO -95 dBm

Documents

3 RAN Performance Tuning NOKIA