Post on 05-Jul-2015
1 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Slowing Down the Inter RAT Cell Reselections; Parameter Tuning & Monitoring GuideVersion 1.0
23.09.2007 Reunanen Jussi
2 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Agenda
• Treselection
• Hysteresis between 3G->2G and 2G->3G cell reselections
• PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble
• PrxAlpha
• PrxTarget
3 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Treselection – Introduction
Treselection: how long the reselection conditions must be fulfilled before reselection is triggered
• Impacts all cell reselections : Inter RAT, intra frequency and inter frequency
• The UE reselects the new cell, if the cell reselection criteria (R-criteria, see next slide) are fulfilled during a time interval Treselection
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Treselection – Introduction
First ranking of all the cells based on CPICH RSCP WCDMA and RSSI GSM( ) ( )
Rs = CPICH RSCP + Qhyst1Rn = Rxlev n ( ) - Qoffset1
First ranking of all the cells based on CPICH RSCP WCDMA and RSSI GSM( ) ( )
Rs = CPICH RSCP + Qhyst1Rn = Rxlev n ( ) - Qoffset1
Rn GSM Rs WCDMA( ) > ( )And
Rxlev GSM ( ) >QrxlevMin
Rn GSM Rs WCDMA( ) > ( )And
Rxlev GSM ( ) >QrxlevMin
YesNo
Cell re-selection to GSM
Cell re-selection to GSM
Neighbour WCDMA or GSM cell calculation with offset
parameter
Serving WCDMA cell calculation, with
hysteresis parameter
UE starts GSM measurements if CPICH Ec No / < qQualMin + sSearchRAT
UE starts GSM measurements if CPICH Ec No / < qQualMin + sSearchRAT
SintraSearch
SinterSearch
SsearchRAT
CPICH EcNo
qQualMin
Second ranking only for WCDMA cells based on CPICH Ec No/
Rs CPICH Ec No Qhyst2= / +Rn CPICH Ec No n -Qoffset2= _ / ( )
Second ranking only for WCDMA cells based on CPICH Ec No/
Rs CPICH Ec No Qhyst2= / +Rn CPICH Ec No n -Qoffset2= _ / ( ) Cell re-selection to
WCDMA cell of highest R value
Cell re-selection to WCDMA cell of highest
R value
5 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Treselection – Recommended Values
As this parameter impacts on all the cell reselections too long Treselection timer might cause problems in high mobility areas but too short timer causes too fast cell reselections and eventually causes also cell reselection ping pongRecommended value 1s should work in every conditions i.e. enough averaging to make sure that correct cell is selectedHowever careful testing is needed to check the performance of different areas• (Dense) Urban area, slow moving UEs with occasional need for fast and
accurate (to correct cell) reselections e.g. outdoor to indoor scenarios or city highways – in some cases cell by cell parameter tuning is performed to find most optimal value between 0s and 2s but typically 1s is optimal value when workload is considered as well
• Highways, fast moving UEs must reselect correct cell – typically 1s works the best (however occasionally also 0s might be needed in fast speed outdoor to indoor cell reselections e.g. tunnels)
• Rural areas, slow or fast moving UEs need very often reselect between different RATs and make proper cell reselections even when the coverage is poor – typically 1s works the best
• Location Area Borders, usually the coverage is fairly poor – typically 1s works the best but sometimes to reduce location area reselection ping pong 1s is used when going from LA1 to LA2 and 2s from LA2 to LA1
6 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Treselection – KPIs and Analysis
RRC connection request amount for inter RAT cell reselection ratio to all RRC Connection request causes
• When Treselection is increased this KPI should decrease
RRC connection request amount for registrations ratio to all RRC Connection request causes
• When Treselection is increased this KPI should decrease
TP_ATTRRC_CONN_SM1001C0
_ATTSELL_RE_SELINTR_RAT_C M1001C42
TP_ATTRRC_CONN_SM1001C0
ON_ATTSREGISTRATI M1001C46
7 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Treselection – KPIs and Analysis
At the same time the CSSR and especially the RRC Connection Setup and Access Complete must be monitored
• The KPIs below should remain the same despite the Treselection modification or even get better
• If the CSSRs or RRC Connection Setup and Access Complete decrease the Treselection value should be decreased
• RNC_94d: RRC Setup and Access Complete Ratio from network point of view
• RNC_565e: CSSR CS Voice (RAS05.1) or RNC_565d : CSSR CS Voice (RAS05)
• The RRC Connection Setup attempts should decrease– M1001C0 RRC_CONN_STP_ATT
8 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Treselection – KPIs and Analysis
• Following RRC Connection Setup failure causes should decrease as the amount of RRC Connection setup attempts is decreasing
– M1001C3 RRC_CONN_STP_FAIL_AC
– M1001C4 RRC_CONN_STP_FAIL_BTS
– M1001C5 RRC_CONN_STP_FAIL_TRANS
– M1001C530 RRC_CONN_STP_FAIL_IUB_AAL2
• Above indicate saved resources and more detailed analysis can be done based on counters below
– BTS CE : RAS05.1
– Iub : AAL2 Path Average Reserved Bandwidth % : RAS05
E_DLMAX_USED_C M5001C3
CE_UL MAX_USED_ M5001C4
E_DLMIN_USED_C M5001C5CE_UL MIN_USED_ M5001C6
E_DLAVG_USED_C M5001C7
E_ULAVG_USED_C M5001C8
RATEGUAR_CELL_AAL2_PATH_ M550C0
SNBR_SAMPLE M550C7ATEVED_CELL_R SUM_RESERM550C1
100% ×
9 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Hysteresis Between 3G->2G and 2G->3G Cell Reselections – Introduction & Recommended Values
Parameters for cell reselections
• Qqualmin = -18dB Ssearch_RAT =2dB -> the 3G->2G cell reselection starts when Ec/No hits -16dB
• FDDQmin/GPRSfddQmin = -14dB (6) and QsearchP/Qsearch = always
The cell reselection paramters 3G -> 2G and 2G -> 3G provide only 2dB hysteresis which is not enough and can been noticed from the RNC statistics as high amount of INTR_RAT_CELL_RE_SEL_ATTS from all the RRC Connection Setup Attempts
• Recommendation is to adjust the GFDM/FDM from -14dB to -10dB (or even up to -8dB) to provide 6 to 8 dB hysteresis between 3G to 2G cell reselection and 2G to 3G cell reselection
On top of Treselection the above parameters will slow down further the 2G to 3G and 3G to 2G cell reselections
10 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Hysteresis Between 3G->2G and 2G->3G Cell Reselections – Introduction & Recommended ValuesHowever careful testing is needed to check the performance of different areas
• UEs must reselect correct cell in case of 3G outdoor to certain 2G – in these cases adjacency based parameter Adjqoffset1 can be used to prioritize certain 2G neighbor
– Impacts the R-criteria as shown below
First ranking of all the cells based on CPICH RSCP WCDMA and RSSI GSM( ) ( )
Rs = CPICH RSCP + Qhyst1Rn = Rxlev n ( ) - Qoffset1
First ranking of all the cells based on CPICH RSCP WCDMA and RSSI GSM( ) ( )
Rs = CPICH RSCP + Qhyst1Rn = Rxlev n ( ) - Qoffset1
11 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Hysteresis Between 3G->2G and 2G->3G Cell Reselections – KPIs and AnalysisRRC connection request amount for inter RAT cell reselection ratio to all RRC Connection request causes
• When hysteresis is increased this KPI should decrease
RRC connection request amount for registrations ratio to all RRC Connection request causes
• When hysteresis is increased this KPI should decrease
TP_ATTRRC_CONN_SM1001C0
_ATTSELL_RE_SELINTR_RAT_C M1001C42
TP_ATTRRC_CONN_SM1001C0
ON_ATTSREGISTRATI M1001C46
12 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Hysteresis Between 3G->2G and 2G->3G Cell Reselections – KPIs and AnalysisAt the same time the CSSR and especially the RRC Connection Setup and Access Complete must be monitored
• The KPIs below should remain the same despite the hysteresis modification or even get better
• If the CSSRs or RRC Connection Setup and Access Complete decrease the hysteresis value should be decreased
• RNC_94d: RRC Setup and Access Complete Ratio from network point of view
• RNC_565e: CSSR CS Voice (RAS05.1) or RNC_565d : CSSR CS Voice (RAS05)
• The RRC Connection Setup attempts should decrease– M1001C0 RRC_CONN_STP_ATT
13 © Nokia Siemens Networks Presentation / Author / DateFor internal use
Hysteresis Between 3G->2G and 2G->3G Cell Reselections – KPIs and Analysis• Following RRC Connection Setup failure causes should decrease as the
amount of RRC Connection setup attempts is decreasing– M1001C3 RRC_CONN_STP_FAIL_AC
– M1001C4 RRC_CONN_STP_FAIL_BTS
– M1001C5 RRC_CONN_STP_FAIL_TRANS
– M1001C530 RRC_CONN_STP_FAIL_IUB_AAL2
• Above indicate saved resources and more detailed analysis can be done based on counters below
– BTS CE : RAS05.1
– Iub : AAL2 Path Average Reserved Bandwidth % : RAS05
E_DLMAX_USED_C M5001C3
CE_UL MAX_USED_ M5001C4
E_DLMIN_USED_C M5001C5CE_UL MIN_USED_ M5001C6
E_DLAVG_USED_C M5001C7
E_ULAVG_USED_C M5001C8
RATEGUAR_CELL_AAL2_PATH_ M550C0
SNBR_SAMPLE M550C7ATEVED_CELL_R SUM_RESERM550C1
100% ×
14 © Nokia Siemens Networks Presentation / Author / DateFor internal use
CLUSTER JBK09
0%
20%
40%
60%
80%
100%
< 50% 50-70% 70-85% 85-100%
85-100% 1 1
70-85% 3 7 1 1
50-70% 12 10 9 7 6 8
< 50% 41 39 47 50 51 48
6/ 19/ 2007 6/ 20/ 2007 6/ 21/ 2007 7/ 10/ 2007 7/ 11/ 2007 7/ 12/ 2007
BEFORE AFTER
Cluster JBK09
Count of % I NTR_RAT_CELL_ RESEL
Comparison Date
Grouping1
Cluster JBK09 Percentage Distribution after implementation:
☺Decreasing black and red colour as high percentage of Inter Rat Cell Reselection
☺Increasing green colour as low percentage of Inter Rat Cell Reselection
Decreasing
☺Before 25% of Cells having >50% of all RRC setups for inter RAT cell reselection
☺After 12% of cells having >50% of all RRC setups for Inter RAT cell reselection
Hysteresis Between 3G->2G and 2G->3G Cell Reselections – KPI Analysis Example
Hysteresis from 2dB -> 6dB
15 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble – Introduction • During drive testing it is usually noted that there are call setup failures where the
network does not seem to respond to RRC Connection Requests with RRC Connection Setup –message
• These are problems due to the spiky UL noise and due to that the power ramping is not aggressive enough to provide high enough Tx power for the terminal during open loop PC
MAJOR ROADS INNER & OUTER BLOCKED COUNT BREAKDOWN
No Immediat e Assignment , 1
No Radio Bearer Set up Complet e, 2
No Aler t ing or Connect , 1
N-300 and T-300 expiry , 4
No Set up, 1RRC Connect ion
Reject , 3
16 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble – Introduction
The parameters affecting to open loop power control are, in brackets are the recommended values:
• PRACH_preamble_retrans (7)
• RACH_tx_Max (16)
• PowerOffsetLastPreamblePRACHmessage (2 dB)
• PowerRampStepPRACHpreamble (2dB)
DownlinkBS
L1 ACK / AICH
UplinkMS Preamble
1
Not detected
Message partPreamble2
PreamblePRACH_preamble_retrans
# PRACH preambles transmitted during one PRACH cycle without receiving AICH response
UEtxPowerMaxPRACH
… … … …
RACH_tx_Max# preamble power ramping cycles that can be
done before RACH transmission failure is reported
PowerRampStepPRACHpreamble
PowerOffsetLastPreamblePRACHmessage
Ptx = CPICHtransmissionPower-RSCP(CPICH) +RSSI(BS) + PRACHRequiredReceivedCI (-20dB)
Ptx = CPICHtransmissionPower-RSCP(CPICH) +RSSI(BS) + PRACHRequiredReceivedCI (-20dB)
17 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble – Recommended Values
• Typically the parameter PRACHRequiredReceivedCI is set to -18…-20dB instead of the default -25dB (typically -20dB is enough)
• Also the parameter PowerRampStepPRACHpreamble is adjusted in case the problem of missed MT calls or call setup failures due to missing RRC Connection Setup still persists (default 2dB usually works the best but in some networks also 3dB is used)
• Check also the values for RACH_tx_Max and PRACH_preamble_retrans– They should be set accordingly as:
– PRACH_preamble_retrans (7)
– RACH_tx_Max (16)
• Also the parameters should all be set in line as below:– PowerOffsetLastPreamblePRACHmessage (2 dB)
– PowerRampStepPRACHpreamble (2dB)
– PRACHRequiredReceivedCI (-20dB)
– PRACH_preamble_retrans (7)
– RACH_tx_Max (16)
18 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble – Recommended Values
• If for example PowerRampStepPRACHpreamble is set to 3dB then other parameters should be adjusted with extra care to avoid unnecessary UL noise spikes
• Current defaults are tested to work properly without excessive increase in UL noise
19 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble – KPIs and Analysis• The impact of this parameter has to be tested with drive testing (as in case the
PRACH preambles are not heard and therefore the RRC Connection Request is not heard by the BTS/RNC no RRC connection setup attempt counter is incremented)
• From the network statistics following should be monitored– RNC_177b Noise Floor of the System– RNC_101b Average Uplink load
▪ Related to above the M1001C3 RRC_CONN_STP_FAIL_AC should not increase (if do then load level reduction actions are needed, explained in PrxAlpha tuning section)
– Secondary KPIs to follow▪ If the CSSRs or RRC Connection Setup and Access Complete decrease the hysteresis
value should be decreased▪ RNC_94d: RRC Setup and Access Complete Ratio from network point of view▪ RNC_565e: CSSR CS Voice (RAS05.1) or RNC_565d : CSSR CS Voice (RAS05)▪ The RRC Connection Setup attempts should increase but the failures should not increase
(especially AC rejections which are related to UL noise increase / Average UL load)• M1001C0 RRC_CONN_STP_ATT• M1001C4 RRC_CONN_STP_FAIL_BTS • M1001C5 RRC_CONN_STP_FAIL_TRANS • M1001C530 RRC_CONN_STP_FAIL_IUB_AAL2
20 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble – KPI Analysis Example
Two values for PRACHRequiredReceivedCI tested (drive testing)
100%
0% 0% 0%
88%
2% 5% 6%
0%
20%
40%
60%
80%
100%
1 2 3 4
# RRC Connection Request Messages per call setup
%
PRACH req. C/I = -20dB PRACH req. C/I = -25dB
Clear improvement in number of needed RRC Connection Request messages per call. For 20dB 100% –of established calls are setup with only 1 RRC Connection Request message
Clear improvement number of sent preambles per RRC Connection Request for 20dB –case. For 20dB 50% of cases –the needed number of preambles is <=4 where as for 25dB it is –~6.5
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2 3 4 5 6 7 8
PRACH req. C/I = -25dB PRACH req. C/I = -20dB
There should be significant improvement also for call setup delay
• -20dB & -25dB : UL interference conditions are at the same level (reported in SIB 7 for both cases)
21 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble – KPI Analysis Example
Clear improvement in call setup delay for 20dB case. ~65% of –the established calls are through with only 3.5 3.7s delay and the –>5.5s delay tail disappears (in this “ ”case).
Two values for PRACHRequiredReceivedCI tested (drive testing)• -20dB
• -25dB
• UL interference conditions are at the same level (reported in SIB 7 for both cases)
96.2%
100.0%
94%
95%
96%
97%
98%
99%
100%
-25dB -20dB
Call Setup Success Rate
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
120.0%
<3.5
s
3.5
s - 3
.7s
3.7
s - 3
.9s
3.9
s - 4
.1s
4.1
s-4.
3s
4.3
s-4
.5s
4.5s
-4.7
s
4.7s
-4.9
s
4.9
s-5
.1s
5.1
s-5
.3s
5.3
s-5
.5s
>5.5
s
Call Setup Delay (seconds) RRC Conn. Req. to Alerting
PRACH req. C/I = -25 PRACH req. C/I = -20
22 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble – KPI Analysis Example
AMR Voice Before 1st drive 2nd driveAverage Preamble
Counts 2.40 2.01 1.617
Average RACH_TX_Pwr -9.11 -7.09 -6.581
average UL interference -102.42 -102.07 -101.53
Video Before 1st drive 2nd driveAverage preamble
count 2.84 1.77 1.933
Average RACH_TX_Pwr -6.95 -6.45 -6.888
average UL interference -102.46 -102.15 -101.33
1. The number of resend for PRACH (Preamble Count) has reduced after the parameters changing, that mean shorter time to build the radio link. 1st drive is after PRACHRequiredReceivedCI been changed (-25dB -> -20dB), while 2nd drive is after RACH_tx_max been changed (8 -> 16)
2. Meanwhile the RACH_TX_Pwr for both AMR and Video services is increased, which mean more power is consumed by the UE .
3. The slighlty increased UL interference can be tried to be reduced by taking the alpha trimmed mean filter into use to filter the Prx measurements in BTS
23 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PRACHRequiredReceivedCI and PowerRampStepPRACHpreamble – KPI Analysis Example
AMR (MOC) Before 1st drive2nd
driveAverage CS call setup time (MOC) 2.36s 2.44s 2.38s
Call Setup Success Rate 97.87% 99.30% 100.00%
24 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxAlpha – Introduction
In case the indicators below have increased due to the open loop PC parameter modifications
• RNC_177b Noise Floor of the System• RNC_101b Average Uplink load
Or in generally if there are high amount of rejections due to following rasons• M1001C3 RRC_CONN_STP_FAIL_AC• M1001C80 RAB_STP_FAIL_CS_VOICE_AC• M1001C85 RAB_STP_FAIL_CS_CONV_AC
The BTS PrxTotal filtering parameters can be modified i.e. how the BTS averages the PrxTotal measurements before sending the results to the RNC in Radio Resource Indication messages
25 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxAlpha – Introduction
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
26 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxAlpha – Introduction
RADIO RESOURCE INDICATION (RRI) messagePrx Total is reported to the RNC for LC, AC and PS usage, on every RRIindicationperiod (200 ms)
The BTS is measuring:Prx Total
BTS sends the LASTEST averaged measurement result to RNC every RRI period
RNC is calculating a sliding window averaged value over the values given by RRI messages
Frame measurements
Prx
…RRIxRRIx+1RRIx+2 RRIx+n
Sliding window average result on every RRI periodWinAcRabSetupUI
∑=
+⋅=m
jjntotalrx Totalx
mP
1
_ _Pr1
BTS uses ALPHA TRIMMED MEAN FILTERPrxAlphaPrxMeasAvWindow
27 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxAlpha – Recommended Values & Example
PrxAlpha=0.1
PrxMeasAveWindow=10
RRIPeriod=200ms
PrxAlpha=0
PrxMeasAveWindow=10
RRIPeriod=200ms
Clearly some impact when changing the PrxAlpha -> suggests that the interference conditions are somewhat spiky and the PrxTotal values could be further reduced adjusting the PrxAlpha
The PrxAlpha parameter value should be adjusted in 0.1 step intervals and KPIs monitored for each parameter value
28 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxAlpha – KPIs and Analysis
Following indicators should be monitored for each PrxAlpha value
• RNC_177b Noise Floor of the System
• RNC_101b Average Uplink load
• M1001C3 RRC_CONN_STP_FAIL_AC
• M1001C80 RAB_STP_FAIL_CS_VOICE_AC
• M1001C85 RAB_STP_FAIL_CS_CONV_AC
29 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxTarget – Introduction
If the received Non-controllable power (RT) + the estimated power increase caused by the to be established RAB is above the PrxTarget, the RT RAB setup is rejectedIf the received Non-controllable power (RT) is above the PrxTarget limit then the RRC Connection Setup is rejected• However note that for the following RRC Connection Request
cause values the AC limits are not used (in UL nor in DL)– Emergency call– Registration– Detach– Originating High Priority Signaling– Terminating High Priority Signalling– Inter-RAT cell re-selection– Inter-RAT cell change order
30 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxTarget – Recommended Values & Example
TOTAL NUMBER OF RRC CONN STP FAIL AC
0
1000
2000
3000
4000
5000
6000
6/1/
200
7
6/2/
200
7
6/3/
200
7
6/4/
200
7
6/5/
2007
6/6/
2007
6/7/
2007
6/8/
2007
6/9/
2007
6/10
/200
7
6/11
/200
7
6/12
/200
7
6/13
/200
7
6/14
/200
7
6/15
/200
7
6/16
/200
7
6/17
/200
7
6/18
/200
7
6/19
/200
7
6/20
/200
7
6/21
/200
7
6/22
/200
7
6/23
/200
7
6/26
/200
7
6/27
/200
7
6/28
/200
7
6/29
/200
7
6/30
/200
7
7/1/
2007
Total Moving Avg
WCELL Name (All) Batch 4th Batch
Sum of RRC_CONN_STP_FAIL_AC
Date
In case the PrxAlpha tuning does not reduce the AC rejections then the PrxTarget can be increased to reduce the AC rejectionsTypically just 2dB increase provides significant reduction on the AC rejections
Starting 16 June 2007 PtxTarget modified 4dB -> 6dB
Starting 16 June 2007 PtxTarget modified 4dB -> 6dB
31 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxTarget – Recommended Values
First the following counters should be checked • RNC_177b Noise Floor of the System
– The above should be compared with the parameter value PrxNoise (WCEL)
– Max(RNC_177b, PrxNoise) = A
• RNC_101b Average Uplink load
• M1000C0 AVE_PRXTOT_CLASS_0, M1000C1 PRXTOT_DENOM_0
• M1000C2 AVE_PRXTOT_CLASS_1, M1000C3 PRXTOT_DENOM_1
• M1000C4 AVE_PRXTOT_CLASS_2, M1000C5 PRXTOT_DENOM_2
• M1000C6 AVE_PRXTOT_CLASS_3, M1000C7 PRXTOT_DENOM_3
• M1000C8 AVE_PRXTOT_CLASS_4, M1000C9 PRXTOT_DENOM_4
32 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxTarget – Recommended Values
First the following counters should be checked • The PrxTotal distribution should be calculated from above and the needed
PrxTarget distribution and average– Average needed PrxTarget; A – RNC101b
– Distribution can be calculated the same way A-AVE_PRXTOT_CLASS_X and the % of samples for each class PRXTOT_DENOM_X/(PRXTOT_DENOM_1+ PRXTOT_DENOM_2+ PRXTOT_DENOM_3+ PRXTOT_DENOM_4+ PRXTOT_DENOM_5)
• Then the PrxTarget parameter tuning should be performed in steps of 2dB towards the highest calculated PrxTotal value
• Max PrxTarget value should not exceed 10dB (in normal conditions without any special interferer)
33 © Nokia Siemens Networks Presentation / Author / DateFor internal use
PrxTarget – KPIs and Analysis
When the PrxTarget is modified following KPIs should be monitored• RNC_177b Noise Floor of the System
• RNC_101b Average Uplink load
• M1001C3 RRC_CONN_STP_FAIL_AC
• M1001C80 RAB_STP_FAIL_CS_VOICE_AC
• M1001C85 RAB_STP_FAIL_CS_CONV_AC
• M1000C0 AVE_PRXTOT_CLASS_0, M1000C1 PRXTOT_DENOM_0
• M1000C2 AVE_PRXTOT_CLASS_1, M1000C3 PRXTOT_DENOM_1
• M1000C4 AVE_PRXTOT_CLASS_2, M1000C5 PRXTOT_DENOM_2
• M1000C6 AVE_PRXTOT_CLASS_3, M1000C7 PRXTOT_DENOM_3
• M1000C8 AVE_PRXTOT_CLASS_4, M1000C9 PRXTOT_DENOM_4
• RNC_94d: RRC Setup and Access Complete Ratio from network point of view
• RNC_565e: CSSR CS Voice (RAS05.1) or RNC_565d : CSSR CS Voice (RAS05)