KPIs in B10 release15 March 2010 End to End Call Setup Success Rate Call Drop Rate Hand Over Success Rate 1 End -To-End Call Setup Success Rate . leading to improved quality . TCH allocation and assignation. giving a view of the call setup success rate from the end user point-of-view.) Benefits Operators would have a global view of the end-user perceived quality of their GSM network. Fastest detection and correction of problems would be possible. etc. This means that the event “call established” would be compared to the event “call requested”.End to End Call Setup Success Rate (1/9) Goal The goal is to provide a new metric. whatever the problems encountered. instead of combining metrics related to the protocol mechanisms like it is done today (SDCCH drops. SDCCH_drop_rate) * ( 1 .SDCCH_SMS_MT_PP_connection)+ SDCCH_traffic_Call_reestab + SDCCH_traffic_lu_for + SDCCH_traffic_other_mo + SDCCH_traffic_moc) .End to End Call Setup Success Rate (2/9) The existing indicator: Call Setup Success Rate = ( 1 .RTCH_assign_unsuccess_rate ) The new indicator: End_to_End_Call_setup_success_rate = (RTCH_assign_success + DR_Out_internal_success + DR_Out_external_success) / ((MT_SDCCH_assign_success . 058 ESTABLISH INDICATION) unknown by the BSC but transferred to the MSC MC02h: Number of SDCCHs successfully seized for Normal or Emergency call . in case of L3 Info (within 48.End to End Call Setup Success Rate (3/9) MC 718 MC142e MC142 f E2E CSSR= MC 01 MC191 MC 02e MC 02d MC 02 f MC 02h MC718: Number of TCH (HR or FR) normal assignment successes. for DTM MC142e: Number of outgoing normal or forced internal directed retry (towards a TCH channel in HR or FR usage) successes MC142f: Number of outgoing normal or forced external directed retry (towards a TCH channel in HR or FR usage) successes MC01: Number of immediate assignment plus SDCCH normal assignment successes for Mobile Terminating procedure MC191: Number of Mobile Terminating SMS connections on SDCCH MC02e: Number of SDCCHs successfully seized for Call Re-establishment MC02d: Number of SDCCHs successfully seized for LU with follow-on bit set to 1 (means that the SDCCH phase will be followed by a TCH assignment for speech call establishment) MC02f: number of immediate assignment successes for Mobile Originating procedure. This counter also takes into account normal assignment successes for TCH establishment in signalling mode (FR usage only). per TRX. End to End Call Setup Success Rate (4/9) MS BTS BSC Radio Link Establishment ESTAB IND (CM_Serv_Req) MSC SDCCH assignment success SCCP CON REQ (CM_Serv_Req) SCCP CON CONFIRM Authentification Procedure Identification Procedure Ciphering Procedure SETUP All call setup failures between MS. BTS. Normal assignment success . BSC and MSC -> End-to-end CSSR CALL PROCEEDING ASSIGNMENT REQUEST Assignment Procedure ASSIGNMENT COMPLETE ALERTING CONNECT CONNECT ACK. but if (in case of core network problem or Ater transmission fault) this message didn’t arrive to the BSC.e. Ideally. SMS/IMSI attach/LU). in case of call establishment. which means that SDCCH drop rate is not accurately representing call establishment cases Classical CSSR formula provides no “link” between the different phases of the call establishment (SDCCH phase &TCH assignment phase). SDCCH phase should be followed by a TCH assignment request message sent from MSC to BSC. E2E CSSR indicator shall take into account this core network problem .RTCH_Assign_unsuccess_rate) This takes into account all SDCCH successes even those that are not related to call establishment (i. this means that it deals with these 2 phases separately.End to End Call Setup Success Rate (5/9) The reason for this difference between classical and E2E CSSR comes from several issues. On the contrary. classical CSSR indicator will not be impacted (because RTCH_assign_unsuccess_rate is based on the reception of TCH assignment request message by the BSC.SDCCH_drop_rate) * (1. listed below: Classical CSSR indicator is calculated as follows: CSSR = (1. End to End Call Setup Success Rate (6/9) If this message is lost. TCH assignment phase will not be triggered SDCCH phase for Originatin g Call . End to End Call Setup Success Rate (7/9) . This leads to inaccurate estimation of SDCCH drop rate. it was seen that number of SDCCH success for TCH establishment purpose is much less than the total number of SDCCH success with all causes.End to End Call Setup Success Rate (8/9) In the study shown in previous slide. that is why a modification was done on SDCCH drop rate to only consider the SDCCHs used for TCH establishment. the values are very close to E2E CSSR (E2E CSSR is better in many cases) . Accordingly. with the modified formula of classical CSSR. End to End Call Setup Success Rate (9/9) Results E2E CSSR is less than classical CSSR by 2% to 3% The values provided by E2E CSSR is always less than that provided by classical CSSR . 2 Call Drop Rate . Radio problems can be due to coverage. .A TC problem can usually be a bad quality of the transmission on the Abis interface (Micro Wave) or a faulty hardware component in the TransCoder or even sometimes BSS software/hardware problems. .A BSS problem can be a BTS/BSC hardware or software failure.Call Drop Rate (1/7) Call Drop Call Drop Radio Call Drop BSS BSS internal Call Drop HO TC . interference and sometimes BSS malfunction which is not detected as a system alarm by the O&M Fault Management application. . Call Drop Rate (2/7) Call drop rate = call drop / RTCH success end RTCH success end= RTCH assignment success + RTCH incoming (HO+DR) success – RTCH Outgoing HO . Call Drop Rate (3/7) QSCDN = call drop = drop radio + drop TC + drop internal BSS + drop HO (+ drop Preemption) = MC736 + MC739 + MC14C + MC621 (+ MC921C) TCQHCCN = RTCH success end = assignment success + incoming (HO+DR) success outgoing HO = MC718 + (MC717A+MC717B) .MC712 . site re-engineering.) to each call drop radio or call drop handover. frequency planning. and therefore to know which actions should be taken (parameters tuning. etc.Call Drop Rate with specific radio causes (new in B10) (4/7) Goal This feature consists in associating a specific radio cause (too low level. Benefits This feature would provide key information to operators for radio network optimization.) to solve these call drop issues . etc. too bad quality. It would indeed provide a fast and efficient way to know the cause of radio related call drops. Call Drop Rate with specific radio causes (new in B10) (5/7) Nine (9) new counters were introduced: TCH drops due to Cause 2 (Too low quality in UL): MC928a TCH drops due to Cause 3 (Too low level in UL): MC928b TCH drops due to Cause 4 (Too low quality on the DL): MC928c TCH drops due to Cause 5 (Too low level in DL): MC928d TCH drops due to Cause 6 (Too long MS-BS distance): MC928e TCH drops due to Cause 22 (Too short MS-BS distance): MC928f TCH drops due to Cause 15 (Too high interference level on the UL): MC928g TCH drops due to Cause 16 (Too high interference level on the DL): MC928h TCH drops due to other causes: MC928i The above counters are triggered by BOTH TCH drop due to radio link failure (radio drops) AND TCH drop during internal/external handover without reversion to old channel (handover drops) . Contribution of Level HO is very small .Call Drop Rate with specific radio causes (new in B10) (6/7) From the above split. we can deduce that most emergency HOs are caused by quality problem. Call Drop Rate with specific radio causes (new in B10) (7/7) From the above split. it is clear that DL quality drops are most common. followed by UL quality. The only level drops (although few ones) are in UL direction Results inline with emergency split . 3 Hand Over Success Rate . Hand Over Success Rate (1/4) . Hand Over Success Rate (2/4) Hand Over Success Case . Hand Over Success Rate (3/4) Hand Over Failure Case: ROC . Hand Over Success Rate (4/4) Hand Over Failure Case: Drop Radio . Thank you .