Utran kpi analysis guide 20051010-b-1.0

4,382 views

Published on

Published in: Self Improvement
0 Comments
4 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
4,382
On SlideShare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
705
Comments
0
Likes
4
Embeds 0
No embeds

No notes for slide

Utran kpi analysis guide 20051010-b-1.0

  1. 1. UTRAN KPI Analysis Guide For Internal Use OnlyHuawei Technologies Co., Ltd Document name Confidentiality level UTRAN KPI Analysis Guide For Internal Use Only RAN Maintenance Dept. Total 46 Pages UTRAN KPI Analysis Guide Prepared by RAN Maintenance Dept. Date Aug. 10, 2005 Reviewed by Date Reviewed by Date Approved by Date Huawei Technologies Co., Ltd. All Rights Reserved
  2. 2. UTRAN KPI Analysis Guide For Internal Use Only Revision Edition Date Version Description AuthorAug. 10, 2005 The first version is complete. Wang Wei
  3. 3. UTRAN KPI Analysis Guide For Internal Use Only Table of Contents1. OVERVIEW..........................................................................................................................................5 1.1 INTENDED AUDIENCE.......................................................................................................................5 1.2 OBJECTIVES......................................................................................................................................52. INTRODUCTION TO NASTAR..........................................................................................................63. UTRAN KPI ANALYSIS.....................................................................................................................6 3.1 NASTAR TASKS................................................................................................................................64. UTRAN KPI ANALYSIS.....................................................................................................................8 4.1 CALL COMPLETION RATE................................................................................................................8 4.1.1 RRC Setup Analysis.....................................................................................................................8 4.1.2 RAB Setup Analysis...................................................................................................................12 4.2 SOFT HANDOVER ANALYSIS..........................................................................................................19 4.2.1 Overview.....................................................................................................................................20 4.2.2 Cell SHO Prepare Failure Analysis............................................................................................22 4.2.3 Cell SHO Failure Analysis.........................................................................................................23 4.3 CS INTER-RAT HANDOVER ANALYSIS.........................................................................................25 4.3.1 Overview.....................................................................................................................................26 4.3.2 CS Inter-RAT Handover Prepare Failure Analysis....................................................................27 4.3.3 CS Inter-RAT Handover Failure Analysis..................................................................................29 4.3.4 Cell Inter-RAT Handover Analysis............................................................................................31 4.4 PS INTER-RAT HANDOVER ANALYSIS..........................................................................................31 4.4.1 Overview.....................................................................................................................................31 4.4.2 PS Inter-RAT Handover Failure Analysis..................................................................................32 4.4.3 Cell Inter-RAT Handover Analysis............................................................................................34 4.5 CELL UPDATE ANALYSIS...............................................................................................................34 4.5.1 Overview.....................................................................................................................................34 4.5.2 Cell Update Failure Analysis......................................................................................................36 4.6 CALL DROP ANALYSIS...................................................................................................................36 4.6.1 Overview.....................................................................................................................................36 4.6.2 CS Call Drop Analysis................................................................................................................37 4.6.3 PS Call Drop Analysis................................................................................................................39 4.6.4 Cell Call Drop Analysis..............................................................................................................40 4.7 TRAFFIC LOAD ANALYSIS..............................................................................................................42 4.7.1 Overview.....................................................................................................................................42 4.7.2 Cell Traffic Analysis...................................................................................................................445. ANALYZING COMPLICATED PROBLEMS..................................................................................46 5.1 NARROWING DOWN AREA RANGE AND TIME RANGE...................................................................46 5.2 ANALYZING ABNORMAL LOGS......................................................................................................46 5.3 ANALYZING REPEATED PROBLEMS................................................................................................46 Aug. 10, 2005 Confidential Information of Huawei Page 3 of 46 No Spreading Without Permission
  4. 4. UTRAN KPI Analysis Guide For Internal Use OnlyAug. 10, 2005 Confidential Information of Huawei Page 4 of 46 No Spreading Without Permission
  5. 5. UTRAN KPI Analysis Guide For Internal Use Only UTRAN KPI Analysis Guide1. Overview In a commercial network, the QoS and network operation are reflected through KPI. UTRAN KPI analysis is a major method used for monitoring and evaluating network operation. UTRAN KPI analysis is also served to track the network traffic, monitor the resource distribution, and facilitate the network expansion and optimization. Huawei UTRAN traffic statistics provides sufficient KPI for network operation, algorithm management, and resource distribution. These traffic statistics can be used to locate network problems and optimize network KPI. UTRAN KPI analysis is a major method for RAN maintenance engineers and network optimization engineers to evaluate network performance. Comparing with drive tests, call detail logs, and alarms, KPI analysis can be used to monitor network operation directly and conveniently. To better locate network problems and optimize network KPI, abnormal indices, call detail logs, tracked messages, and drive tests can be used together. Huawei provides a traffic statistics analysis tool Nastar for UTRAN KPI analysis. Nastar can be used to obtain and analyze UTRAN KPI. This guide introduces how to use Nastar to analyze UTRAN KPI. For more information, refer to GENEX Nastar V400R001C01 User Manual.1.1 Intended Audience This guide, intended for network maintenance engineers and site audit engineers, introduces Nastar V400R001, which supports the KPI analysis of RNC V100R002C03B092 and RNC V100R002C03B151.1.2 Objectives This guide aims to provide guidance for network maintenance personnel to monitor network KPI on a timely basis, analyze abnormal indices, and find outAug. 10, 2005 Confidential Information of Huawei Page 5 of 46 No Spreading Without Permission
  6. 6. UTRAN KPI Analysis Guide For Internal Use Only practical solutions.2. Introduction to Nastar Nastar provides such functions as index defining, query defining, and report generating. For more information, refer to GENEX Nastar V400R001C01 User Manual.3. UTRAN KPI Analysis The QoS of communication network is defined in ITU-T E.800. Considering the features of wireless communication network, the following KPI must be considered for WCDMA RAN, as shown in Table 1-1. Network performance KPI Call completion rate RRC Setup Success Rate RAB Setup Success Rate Call drop rate Voice Call Drop Rate VP Call Drop Rate PS Call Drop Rate Mobility management Soft Handover Success Rate Inter-Frequency HO Success Rate Intra-Frequency HO Success Rate CS Inter-RAT HO Success Rate PS Inter-RAT HO Success Rate Cell Update Success Rate Traffic Equivalent User Cell Throughput Cell Resource Allocation Table 1-1 WCDMA RAN KPI3.1 Nastar Tasks Figure 1-1 shows a list of Nastar tasks.Aug. 10, 2005 Confidential Information of Huawei Page 6 of 46 No Spreading Without Permission
  7. 7. UTRAN KPI Analysis Guide For Internal Use Only Figure 1-1 Nastar tasks Perf Daily Report and Perf Weekly Report can be generated in .xls file by Nastar. An object can be a self-defined clutter or RNC. Perf Daily Report is used to monitor network performance. By default, Perf Daily Report includes the following KPI, as shown in Table 1-2. RNC Name RNC 1 : CS User Based on Equivalent User 17.13(16:00 ~ 17:00) Traffic PS User Based on Equivalent User 54.09(12:00 ~ 13:00) RRC Connection Setup Success Rate(service)(>95%) 98.64%(2468/2502) RRC Connection Setup Success Rate(other)(>95%) 96.87%(36445/37624) AMR RAB Assignment Success Rate(>95%) 99.00%(990/1000) Access Video Call RAB Assignment Success Rate(>95%) 100.00%(29/29) PS RAB Assignment Success Rate(>95%) 99.60%(997/1001) RB Setup Success Rate(>95%) 99.31%(2016/2030) Soft Handover Success Rate(>98%) 99.75%(17090/17132) Softer Handover Success Rate(>98%) 99.66%(3509/3521) Soft Handover Factor based on Radio Link Number(<40%) 18.85% HO Inter-Freq Hard Handover Success Rate(>85%) 100.00%(16/16) CS Inter-RAT Handover Success Rate( from UTRAN to GSM)(>85%) 100.00%(4/4) PS Inter-RAT Handover Success Rate( from UTRAN to GSM)(>85%) 66.67%(4/6) CS AMR Call Drop Rate(<1.5%) 1.92%(19/990) CDR Video Call Drop Rate(<1.5%) 10.34%(3/29) PS Service Drop Rate(<30%) 3.01%(30/997)Aug. 10, 2005 Confidential Information of Huawei Page 7 of 46 No Spreading Without Permission
  8. 8. UTRAN KPI Analysis Guide For Internal Use Only Table 1-2 Perf Daily Report If network performance cannot meet the previous KPI or the KPI is changed, refer to Section 4 UTRAN KPI Analysis.4. UTRAN KPI Analysis4.1 Call Completion Rate This section consists of the following parts:  RRC Setup Analysis  RAB Setup Analysis4.1.1 RRC Setup Analysis 1. Overview RRC Setup Analysis is included in Nastar, as shown in Figure 1-1. Double click RRC Setup Analysis to display the RRC setup details, as shown in Figure 1-3. RRC setup success rate is 97.3%. Most RRC setup failures result from RRC Setup Fail No Response while few RRC setup failures (seven times) result from RRC Setup Reject. 78,961 RRC_SETUP_SUCC 7 RRC_REJ 2,186 RRC_SETUP_FAIL_NO_RSP 97.3 % 2.69 % 0.01 % Figure 1-3 RRC SetupAug. 10, 2005 Confidential Information of Huawei Page 8 of 46 No Spreading Without Permission
  9. 9. UTRAN KPI Analysis Guide For Internal Use Only There are two reasons for RRC Setup Fail No Response:  Downlink FACH and RACH are covered unevenly. The networks, built during the early period, are covered poorly. In particular, inter-system reselection areas are covered poorly.  A certain area has too many subscribers or any equipment in this area is faulty. 2. RRC Setup Scenario Analysis One of the reasons for RRC Setup Fail No Response is poor coverage, so RRC setup reasons and RRC setup success rate can be used for further analysis. Start Scenario Analysis to display a pie or bar chart for presenting RNC indices. 7,451 RRC_REQ_ORG 6.97 % 5,639 RRC_REQ_TERM 51,385 RRC_REQ_CELL_RESEL 16,387 RRC_REQ_REG 9.21 % 63.55 % 20.27 % Figure 1-4 RRC setup scenario (pie chart) Use Scenario Analysis to analyze RRC setup scenarios, as shown in Figure 1-5. Most RRC setup requests are caused by:  RRC REQ CELL RESEL If network coverage is poor, inter-system reselection may occur.  RRC REQ REG If network coverage is poor, subscribers attempt to register for many times.Aug. 10, 2005 Confidential Information of Huawei Page 9 of 46 No Spreading Without Permission
  10. 10. UTRAN KPI Analysis Guide For Internal Use Only 0.99 0.985 0.98 0.975 Bar Value 0.97 0.965 0.96 0.955 0.95 0.945 0 Time b c d e f g RNC:41(ID:41)-RRC_SETUP_SUCC_RATE_ORG b c d e f g RNC:41(ID:41)-RRC_SETUP_SUCC_RATE_TERM b c d e f g RNC:41(ID:41)-RRC_SETUP_SUCC_RATE_INTERRAT_CELL_RESEL b c d e f g RNC:41(ID:41)-RRC_SETUP_SUCC_RATE_REG Figure 1-5 RRC setup scenario (bar chart) Figure 1-5 shows RRC setup success rates. RRC SETUP SUCC RATE ORG is very high while RRC SETUP SUCC RATE REG is very low. On Huawei networks, resident threshold Ec/Io is greater than -18 dB while inter-system reselection start threshold Ec/Io is less than -14 dB. Low RRC SETUP SUCC RATE REG indicates that many registrations are attempted within the area (Ec/Io falls between -14 dB and -18 dB), which has poor coverage. High RRC SETUP SUCC RATE ORG (99%) indicates that the network is covered by PCH and RRC SETUP SUCC RATE can be high in a well-covered network. 3. RRC Setup Reject Analysis RRC setup reject are caused by:  Admission reject due to crowded subscribers  Access failure due to equipment faults RRC setup reject may occur no matter how poor network coverage is; however, RRC setup reject occurs in a small-scale network. Therefore, only the areas of RRC setup reject must be analyzed. In RRC Setup Analysis, start Cell RRC Analysis to query the TOPN. The queried results are outputted in three pages: (1) The top ten cells that have the highest RRC setup reject times.Aug. 10, 2005 Confidential Information of Huawei Page 10 of 46 No Spreading Without Permission
  11. 11. UTRAN KPI Analysis Guide For Internal Use Only (2) The top ten cells that have the highest RRC setup success rates. (3) The top ten cells that have the highest RRC setup failure rates. For the top ten cells that have the maximum RRC setup fail rates, start Cell Scenario Analysis for further analysis. For the top ten cells that have the maximum RRC setup rejects, start Cell RRC Reject Analysis for further analysis. 2 RRC_REJ_POWER_CONG_CELL 0 RRC_REJ_CE_CONG_CELL 0 RRC_REJ_RL_FAIL_CELL 0 RRC_REJ_AAL2_FAIL_CELL 0 RRC_REJ_FP_FAIL_CELL 0 RRC_REJ_CODE_CONG_CELL 0 RRC_REJ_OTHER_CELL 100 % 0% 0% Figure 1-6 RRC setup reject analysis Figure 1-6 shows the results of Cell RRC Reject Analysis. In this figure, two RRC setup rejects are caused by Power Congestion. RRC setup reject may be caused by the following reasons: (1) Power Congestion RRM performs the admission algorithm decision but uplink or downlink admission decision is rejected, so RRC setup reject occurs. If network load is heavy, power congestion may occur. To locate the problem, start Cell Traffic Load Analysis to check whether uplink or downlink is congested by focusing on the maximum RTWP and the maximum TCP. If power congestion is confirmed, check whether the threshold is reasonable, check whether there is any interference, and check whether the network capacity is insufficient. (2) CE CongestionAug. 10, 2005 Confidential Information of Huawei Page 11 of 46 No Spreading Without Permission
  12. 12. UTRAN KPI Analysis Guide For Internal Use Only If there are many subscribers, CE resources may become insufficient in RNC. To locate the problem, start Cell Traffic Load Analysis to check the DCH user number and forecast the required CE quantity in accordance with the traffic model. (3) RL Fail During the RRC setup process, NodeB recognizes RRC setup fail because NodeB fails or NodeB resource is insufficient. To locate the problem start Cell Traffic Load Analysis to check the DCH user number. Analyze the data and logs of the boards or CEs in NodeB to check whether NodeB fails or NodeB resource is insufficient. (4) AAL2 Fail If transmission resource is insufficient or any transmission equipment is faulty, the AAL2 path setup of lub interface may fail. To locate the problem, start Cell Traffic Load Analysis to check the DCH user number and the bandwidth of AAL2 path. Check whether transmission resource is insufficient or any transmission equipment is faulty. (5) FP Fail If the transmission fails or an equipment is faulty, FP synchronization may fail. To locate the problem, check whether there is any BTS alarm. (6) Code Congestion If there is high traffic in the indoor micro cell, code resource may be insufficient. To locate the problem, start Cell OVSF Code Allocation Analysis to analyze the code allocation and confirm major services. (7) Other If there is any problem in RNC, RRC setup reject may occur. To locate the problem, analyze call detail logs.4.1.2 RAB Setup Analysis 1. OverviewAug. 10, 2005 Confidential Information of Huawei Page 12 of 46 No Spreading Without Permission
  13. 13. UTRAN KPI Analysis Guide For Internal Use Only Figure 1-7 Nastar tasks Figure 1-7 shows a list of Nastar tasks. RAB Setup Analysis is included in Nastar. Double click RAB Setup Analysis to display RAB setup details, as shown in Figure 1-8. 2,370 CS_RAB_REQ_SETUP_CONV_0_32 73.37 % 101 CS_RAB_REQ_SETUP_CONV_32_64 5 PS_RAB_REQ_SETUP_64K 5 PS_RAB_REQ_SETUP_128K 749 PS_RAB_REQ_SETUP_384K 23.19 % 3.13 % 0.15 % 0.15 % Figure 1-8 RAB setup analysis Check such RAB setup rates as CS_RAB_REQ_SETUP_CONV_0_32 (AMR), CS_RAB_REQ_SETUP_CONV_32_64 (VP), 64 K (PS), 128 K (PS), and 384 KAug. 10, 2005 Confidential Information of Huawei Page 13 of 46 No Spreading Without Permission
  14. 14. UTRAN KPI Analysis Guide For Internal Use Only (PS) to confirm major services in the network. Click Produce a Bar Chart to display the RB and RAB setup success rates, as shown in Figure 1-9. 1.1 1 0.9 0.8 0.7 Bar Value 0.6 0.5 0.4 0.3 0.2 0.1 0 0 Time b c d e f g RNC:1(ID:1)-RB_SETUP_SUCC_RATE b c d e f g RNC:1(ID:1)-CS_RAB_ SETUP_SUCC_RATE_AMR b c d e f g RNC:1(ID:1)-CS_RAB_ SETUP_SUCC_RATE_VP b c d e f g RNC:1(ID:1)-PS_RAB_SETUP_SUCC_RATE_64K b c d e f g RNC:1(ID:1)-PS_RAB_SETUP_SUCC_RATE_128K g b c d e f RNC:1(ID:1)-PS_RAB_SETUP_SUCC_RATE_384K Figure 1-9 RB and RAB setup success rates 2. RAB Setup Fail Analysis In RAB Setup Analysis, start Cell RAB Analysis to query the TOPN. The queried results are outputted in four pages: (1) The top ten cells that have the highest CS RAB setup failures. (2) The top ten cells that have the lowest CS RAB setup failures. (3) The top ten cells that have the highest PS RAB setup failures. (4) The top ten cells that have the lowest PS RAB setup failures. Low RAB setup success rate may occur in the cells that have lowest setup times. To locate the problem, focus on the cells that have the lowest setup failures because the KPI is affected mostly by these cells. If CS RAB setup fail rate is high in a cell, start Cell CS RAB Setup Fail Analysis to display the CS RAB setup fail rates, as shown in Figure 1-10.Aug. 10, 2005 Confidential Information of Huawei Page 14 of 46 No Spreading Without Permission
  15. 15. UTRAN KPI Analysis Guide For Internal Use Only 1,571 CS_RAB_SETUP_SUCC_CONV_CELL 0 CS_RAB_SETUP_SUCC_STR_CELL 0 CS_RAB_SETUP_FAIL_PARAM_CELL 0 CS_RAB_SETUP_FAIL_RELOC_CELL 10 CS_RAB_SETUP_FAIL_TNL_CELL 0 CS_RAB_SETUP_FAIL_CONG_CELL 0 CS_RAB_SETUP_FAIL_POWER_CONG_CELL 99.05 % 0 CS_RAB_SETUP_FAIL_CE_CONG_CELL 0% % 0% 0.63 0 CS_RAB_SETUP_FAIL_CODE_CONG_CELL 0% 0% % 0.32 5 CS_RAB_SETUP_FAIL_OTHER_CELL 0% Figure 1-10 Cell CS RAB setup fail analysis Cell CS RAB setup failures may be caused by the following reasons: (1) PARAM_CELL RNC regards the parameters transmitted by core network as invalid parameters. This reason seldom occurs. To locate the problem, track the signaling and check the RAB setup messages in specific cells. (2) RELOC_CELL When initializing the migration process, RNC receives the RAB setup request messages but RNC does not process the request. This reason is mainly caused by the process integration related to subscriber action sequence, so this reason seldom occurs. In a core network, this situation is always avoided. (3) TNL_CELL RAB setup fails because IU transmission setup fails. To locate the problem, check the transmission capacity and operation stability. (4) CONG_CELL This may be caused by RNC resource allocation failure. To locate the problem, analyze the RNC logs and obtain the detailed resource failure information. (5) POWER_CONG_CELLAug. 10, 2005 Confidential Information of Huawei Page 15 of 46 No Spreading Without Permission
  16. 16. UTRAN KPI Analysis Guide For Internal Use Only According to RRM admission decision, new RAN cannot be set up because cell load is too heavy. To locate the problem, check whether the parameters of admission algorithm are reasonable. If yes, consider to optimize the coverage and expand the capacity. (6) CE_CONG_CELL CE resource admission fails in RNC. CE must be expanded. (7) CODE_CONG_CELL During the RAB setup process, code resource allocation fails because too many subscribers are crowded on the network or code resource allocation fails. To locate the problem, analyze the code resource of cell traffic to check whether code resource is restricted due to cell overload. (8) OTHER_CELL This may caused by RB setup failure or other reasons. To locate the problem, analyze RB setup success rates. If PS RAB setup fail rate is high, start Cell PS RAB Setup Fail Analysis to display the PS RAB setup fail rates, as shown in Figure 1-11. 0 PS_RAB_SETUP_SUCC_CONV_CELL 0 PS_RAB_SETUP_SUCC_STR_CELL 37 PS_RAB_SETUP_SUCC_INTER_CELL 84.09 % 0 PS_RAB_SETUP_SUCC_BKG_CELL 0 PS_RAB_SETUP_FAIL_PARAM_CELL 0 PS_RAB_SETUP_FAIL_RELOC_CELL 0 PS_RAB_SETUP_FAIL_CONG_CELL 3 PS_RAB_SETUP_FAIL_POWER_CONG_CELL 0% 0 PS_RAB_SETUP_FAIL_CE_CONG_CELL 0% 0 PS_RAB_SETUP_FAIL_CODE_CONG_CELL 4 PS_RAB_SETUP_FAIL_OTHER_CELL 9.09 % 0% 0% 6.82 % 0% 0% Figure 1-11 Cell PS RAB setup fail analysis Cell CS RAB setup failure may be caused by the following reasons: (1) PARAM_CELL RNC regards the parameters transmitted by core network as invalidAug. 10, 2005 Confidential Information of Huawei Page 16 of 46 No Spreading Without Permission
  17. 17. UTRAN KPI Analysis Guide For Internal Use Only parameters. This reason seldom occurs. To locate the problem, track the signaling and check the RAB setup messages in specific cells. (2) RELOC_CELL When initializing the migration process, RNC receives the RAB setup request messages but RNC does not process the request. This reason is mainly caused by the process integration related to subscriber action sequence, so this reason seldom occurs. In a core network, this situation is always avoided. (3) TNL_CELL RAB setup fails because IU transmission setup fails. To locate the problem, check the transmission capacity and operation stability. (4) CONG_CELL This may be caused by RNC resource allocation failure. To locate the problem, analyze the RNC logs and obtain the detailed resource failure information. (5) POWER_CONG_CELL According to RRM admission decision, new RAN cannot be set up because cell load is too heavy. To locate the problem, check whether the parameters of admission algorithm are reasonable. If yes, consider to optimize the coverage and expand the capacity. (6) CE_CONG_CELL CE resource admission fails in RNC. CE must be expanded. (7) CODE_CONG_CELL During the RAB setup process, code resource allocation fails because too many subscribers are crowded on the network or code resource allocation fails. To locate the problem, analyze the code resource of cell traffic to check whether code resource is restricted due to cell overload. (8) UNSUP_CELL During the RAB setup process, the QoS is not supported by RNC or RRMAug. 10, 2005 Confidential Information of Huawei Page 17 of 46 No Spreading Without Permission
  18. 18. UTRAN KPI Analysis Guide For Internal Use Only admission fails in RAB. (9) OTHER_CELL This may caused by RB setup failure or other reasons. To locate the problem, analyze RB setup success rates. In a commercial network, RAB setup is mainly caused by admission failure and RB setup failure. To analyze the RB setup failure, start Cell RB Setup Fail Analysis to display the RB setup fail rates, as shown in Figure 1-12. 1,645 RB_SETUP_SUCC_CELL 0 RB_SETUP_FAIL_CFG_UNSUPP_CELL 0 RB_SETUP_FAIL_PHYCH_FAIL_CELL 0 RB_SETUP_FAIL_SIMU_RECFG_INCOMP_CELL 0 RB_SETUP_FAIL_CELL_UPDT_CELL 3 RB_SETUP_FAIL_CFG_INVALID_CELL 1 RB_SETUP_FAIL_NO_RSP_CELL 99.76 % 0.18 % 0 RB_SETUP_FAIL_OTHER_CELL 0% % 0.06 0% Figure 1-12 Cell RB setup fail analysis Cell RB setup failure may be caused by the following reasons: (1) CFG_UNSUPP UE acknowledges the RB setup failure because of configuration unsupported. This reason seldom occurs in the network. It is mainly caused by compatibility problem of UE in some unknown scenarios. (2) PHYCH_FAIL The RB setup failure may occur if FACH is migrated to DCH but downlink physical layers are not synchronized during the RB setup process. The rooted reason is poor coverage. (3) SIMU_RECFG_INCOMP UE regards that the RB setup process and other processes simultaneously occur and they are incompatible. RNC processing ensures RRC processes nesting. This reason seldom occurs. It is mainly caused by UE defects.Aug. 10, 2005 Confidential Information of Huawei Page 18 of 46 No Spreading Without Permission
  19. 19. UTRAN KPI Analysis Guide For Internal Use Only (4) CELL_UPDT During the RB setup process, the Cell Update process occurs. The RB setup failure is caused by process nesting. (5) CFG_INVALID UE regards the configured parameters are invalid ones. This reason seldom occurs. It is mainly caused by inconsistent understanding of network and UE. (6) NO_RESPONSE UE does not acknowledge the RB setup request. This reason frequently occurs. It is mainly caused by poor coverage, so UE cannot receive the RB setup request message. (7) OTHER Cell RB setup failure is caused by other reasons. To locate the problem, analyze call detail logs.4.2 Soft Handover Analysis This section consists of the following parts:  Overview  Cell SHO Prepare Failure Analysis  Cell SHO Failure AnalysisAug. 10, 2005 Confidential Information of Huawei Page 19 of 46 No Spreading Without Permission
  20. 20. UTRAN KPI Analysis Guide For Internal Use Only4.2.1 Overview Figure 1-13 Nastar Tasks Soft Handover Analysis is included in Nastar tasks, as shown in Figure 1-13. Double click Soft Handover Analysis to display the RNC soft handover details (including soft handover success rate, softer handover success rate, and soft handover prepare success rate), as shown in Figure 1-14.Aug. 10, 2005 Confidential Information of Huawei Page 20 of 46 No Spreading Without Permission
  21. 21. UTRAN KPI Analysis Guide For Internal Use Only 1.005 1 0.995 0.99 0.985 0.98 Bar Value 0.975 0.97 0.965 0.96 0.955 0.95 0.945 0.94 0.935 0 Time b c d e f g RNC:1(ID:1)-SHO_SUCC_RATE b c d e f g RNC:1(ID:1)-SOFTERHO_SUCC_RATE b c d e f g RNC:1(ID:1)-SHO_PREP_SUCC_RATE Figure 1-14 Soft Handover Analysis In the previous figure, soft handover factor is used to measure the proportion and cost of soft handover. SHO_FACTOR_RL and SHO_FACTOR_UE are defined as follows:  SHO_FACTOR_RL SHO_FACTOR_RL is used to measure average link number. SHO_FACTOR-RL can be calculated as follows: (Subscriber number of link 1 of active set*1 + Subscriber number of link 2 of active set*2 + Subscriber number of link 3 of active set*3)/Total subscriber number – 1 SHO_FACTOR_RL is used to indicate the influence of soft handover exerted on NodeB CE and to evaluate the subscriber resource utililization.  SHO_FACTOR_UE SHO_FACTOR_UE is used to measure the proportion of soft handover subscribers. SHO_FACTOR_UE can be calculated as follows: (Subscriber number of link 2 of active set + Subscriber number of link 3 of active set)/Total subscriber number SHO_FACTOR_UE is used to indicate the subscribers in the soft handover area, which is similar to the proportion of soft handover area by making drive tests. SHO_FACTOR_UE is used to measure the reasonableAug. 10, 2005 Confidential Information of Huawei Page 21 of 46 No Spreading Without Permission
  22. 22. UTRAN KPI Analysis Guide For Internal Use Only relationship between soft handover area and soft handover distribution. SHO_FACTOR_UE is greater than SHO_FACTOR_UE. The greater the difference between them is, the greater the subscriber number of link 3 of active set is. If the subscriber number of link 3 of active set is very great, SHO_FACTOR_RL is greater than 1 while SHO_FACTOR_UE is less than 1.4.2.2 Cell SHO Prepare Failure Analysis In the Soft Handover Analysis, start Cell SHO Analysis to query the TOPN. The queried results are outputted in four pages: (1) The top ten cells that have the highest soft handover failure times (2) The top ten cells that have the lowest soft handover success rates (3) The top ten cells that have the highest soft handover prepare failure times (4) The top ten cells that have the lowest soft handover prepare success rates During the early period, low soft handover success rates may exist in the cells that have less soft handover times. Attention must be paid to the cells that have the highest soft handover failure times and the highest soft handover prepare failure times because they affect the KPI of soft handover greatly. To query the cells that have the highest soft handover prepare failure times, start Cell SHO Prepare Failure Analysis to display the soft handover prepare failure details, as shown in Figure 1-15. 0 SHO_PREP_RL_SETUP_FAIL 7 SHO_PREP_AAL2_SETUP_FAIL 0 SHO_PREP_FP_SYNC_FAIL 0% 67 SHO_PREP_FAIL_OTHER_CELL 9.46 % 0% 90.54 % Figure 1-15 Cell SHO Prepare Failure AnalysisAug. 10, 2005 Confidential Information of Huawei Page 22 of 46 No Spreading Without Permission
  23. 23. UTRAN KPI Analysis Guide For Internal Use Only Cell SHO prepare failure may be caused by the following reasons: (1) SHO_PREP_RL_SETUP_FAIL The links cannot be added during the soft handover because NodeB CE resource is insufficient or NodeB is faulty. Internal NodeB logs, Cell Traffic Load Analysis, and data configuration of NodeB boards can be used to locate the problems. If NodeB CE resource is insufficient, one or more boards must be added for expansion. (2) SHO_PREP_AAL2_SETUP_FAIL When the links are added during the soft handover, the AAL2 setup of lub interface fails because the transmission bandwidth is insufficient. If the transmission bandwidth is insufficient, transmission equipments must be expanded. (3) SHO_PREP_FP_SYNC_FAIL When the links are added during the soft handover, the synchronization of AAL2 and FP of lub interface fails. To locate the problem, check whether the intermittent transmission interruption occurs or the IMA group transmission is incorrectly configured. (4) SHO_PREP_ FAIL_OTHER_CELL Soft handover prepare failure is caused by other reasons, such as insufficient RNC resource, radio resource admission reject, and RNC link state reject. To locate the problem, RNC logs must be used for further analysis.4.2.3 Cell SHO Failure Analysis In the Soft Handover Analysis, start Cell SHO Analysis to query the TOPN. The queried results are outputted in four pages: (1) The top ten cells that have the highest soft handover failure times (2) The top ten cells that have the lowest soft handover success rates (3) The top ten cells that have the highest soft handover prepare failure timesAug. 10, 2005 Confidential Information of Huawei Page 23 of 46 No Spreading Without Permission
  24. 24. UTRAN KPI Analysis Guide For Internal Use Only (4) The top ten cells that have the lowest soft handover prepare success rates During the early period, low soft handover success rates may exist in the cells that have less soft handover times. Attention must be paid to the cells that have the highest soft handover failure times and the highest soft handover prepare failure times because they affect the KPI of soft handover greatly. In the Cell SHO Analysis, start Cell SHO Failure Analysis to display the soft handover failure details, as shown in Figure 1-16. 2,797 SHO_SUCC_CELL 0 SHO_RL_ADD_FAIL_CFG_UNSUPP 0 SHO_RL_ADD_FAIL_SIMU_RECFG_INCOMP 0 SHO_RL_ADD_FAIL_CFG_INVALID 4 SHO_RL_ADD_FAIL_NO_RSP 0% % 0.11 0 SHO_RL_DEL_FAIL_CFG_UNSUPP 0 SHO_RL_DEL_FAIL_SIMU_RECFG_INCOMP 99.75 % 0% % 0.14 0 SHO_RL_DEL_FAIL_CFG_INVALID 0% 0% 3 SHO_RL_DEL_FAIL_NO_RSP 0 SHO_FAIL_OTHER_CELL 0% Figure 1-16 Cell SHO Failure Analysis Soft handover failure may be caused by the following reasons: (1) SHO_RL_ADD_FAIL_CFG_UNSUPP UE does not support to add radio links in RNC during the active set update. This reason seldom exists in a commercial network. (2) SHO_RL_ADD_FAIL_SIMU_RECFG_INCOMP UE feeds back that the soft handover process is incompatible with other concurrent processes when radio links are added in RNC. When handling the processes, RNC performs the serial connection. The problem is mainly caused by some handsets. (3) SHO_RL_ADD_FAIL_CFG_INVALID UE regards active set update of adding radio links in RNC as invalid configuration. This reason seldom occurs in a commercial network. (4) SHO_RL_ADD_FAIL_NO_RSPAug. 10, 2005 Confidential Information of Huawei Page 24 of 46 No Spreading Without Permission
  25. 25. UTRAN KPI Analysis Guide For Internal Use Only RNC does not receive the acknowledgement of active set update of adding radio links. Soft handover failure is mainly caused by this reason. If network coverage is poor or soft handover area is small, soft handover failure easily occurs. Thus, the RF optimization is required. (5) SHO_RL_DEL_FAIL_CFG_UNSUPP UE does not support to delete radio links in RNC during the active set update. This reason seldom occurs in a commercial network. (6) SHO_RL_ADD_FAIL_SIMU_RECFG_INCOMP UE feeds back that the soft handover is incompatible with other concurrent processes when radio links are deleted in RNC. When handling the processes, RNC performs the serial connection. The problem is mainly caused by some handsets. (7) SHO_RL_ADD_FAIL_CFG_INVALID UE regards the active set update of deleting radio links in RNC as invalid configuration. This reason seldom occurs in a commercial network. (8) SHO_RL_ADD_FAIL_NO_RSP RNC does not receive the acknowledgement of active set update of deleting radio links. Soft handover failure is mainly caused by this reason. If network coverage is poor or soft handover area is small, soft handover failure easily occurs. Thus, the RF optimization is required. (9) SHO_FAIL_OTHER_CELL Soft handover failure is caused by other reasons; however, soft handover failure is seldom caused by other reasons. If soft handover failure is caused by other reasons, analyze the logs to locate the problems.4.3 CS Inter-RAT Handover Analysis This section consists of the following parts:  Overview  CS Inter-RAT Handover Prepare Failure Analysis  CS Inter-RAT Handover Failure AnalysisAug. 10, 2005 Confidential Information of Huawei Page 25 of 46 No Spreading Without Permission
  26. 26. UTRAN KPI Analysis Guide For Internal Use Only  Cell Inter-RAT Handover Analysis4.3.1 Overview Figure 1-17 Nastar tasks CS Inter-RAT Handover Analysis is included in Nastar tasks, as shown in Figure 1-17. Double click CS Inter-RAT Handover Analysis to display the CS inter-RAT handover details between a 2G network and a 3G network (including CS inter- RAT handover success rate, CS inter-RAT handover prepare failure rate, and CS inter-RAT handover failure rate), as shown in Figure 1-18. In a commercial network, CS inter-RAT handover between a 2G network and a 3G network seldom occurs.Aug. 10, 2005 Confidential Information of Huawei Page 26 of 46 No Spreading Without Permission
  27. 27. UTRAN KPI Analysis Guide For Internal Use Only 605 CS_INTRAT_HO_OUT_PREP_FAIL 2,735 CS_INTRAT_HO_OUT_SUCC 40 CS_INTRAT_HO_OUT_FAIL 17.9 % 1.18 % 80.92 % Figure 1-18 CS Inter-RAT Handover Analysis4.3.2 CS Inter-RAT Handover Prepare Failure Analysis In the CS Inter-RAT Handover Analysis, start CS Inter-RAT Handover Prepare Failure Analysis to display the CS inter-RAT handover details, as shown in Figure 1-19. 2,775 CS_INTRAT_HO_OUT_PREP_SUCC 0 CS_INTRAT_HO_OUT_PREP_FAIL_TARGET_FAIL 0 CS_INTRAT_HO_OUT_PREP_FAIL_TALLOC_EXPIR 82.1 % 0 CS_INTRAT_HO_OUT_PREP_FAIL_TARGET_UNSUPP 13 CS_INTRAT_HO_OUT_PREP_FAIL_RELOC_ABORT 560 CS_INTRAT_HO_OUT_PREP_FAIL_NO_RSRC_AVAIL 0 CS_INTRAT_HO_OUT_PREP_FAIL_UNKNOWTARGET 0% 0% 32 CS_INTRAT_HO_OUT_PREP_FAIL_REQINFNOTAVAI 0.95 % 0 CS_INTRAT_HO_OUT_PREP_FAIL_NO_RSP 0% 0 CS_INTRAT_HO_PREP_FAIL_OTHER 16.57 % 0.38 % 0% 0% Figure 1-19 CS inter-RAT handover prepare failure analysis CS inter-RAT handover prepare failure may be caused by the following reasons: (1) CS_INTERRAT_HO_PREP_FAIL_TARGET_FAIL CS inter-RAT handover prepare failure is caused by Relocation Failure Target CN/RNC or Target System (cause value) because the dataAug. 10, 2005 Confidential Information of Huawei Page 27 of 46 No Spreading Without Permission
  28. 28. UTRAN KPI Analysis Guide For Internal Use Only configuration of core network is incorrect or BSS does not support the handover. To locate the problem, track the signaling of core network and BSS for further analysis. (2) CS_INTERRAT_HO_PREP_FAIL_TALLOC_EXPIR CS inter-RAT handover prepare failure is caused by TRELOCalloc Expiry (cause value) because the data configuration or link connection of core network is incorrect. To locate the problem, track the signaling of core network and BSS for further analysis. (3) CS_INTERRAT_HO_PREP_FAIL_TARGET_UNSUPP CS inter-RAT handover prepare failure is caused by Relocation Not Supported in Target RNC or Target System (cause value) because BSC does not support some parameters of handover requests. To locate the problem, track the signaling of core network and BSS for further analysis. (4) CS_INTERRAT_HO_PREP_FAIL_RELOC_ABORT After sending the handover prepare request, RNC receives the release message from core network. This may be caused by two reasons: (1) Inter-RAT handover is requested during the signaling processes, such as location update. Location update process is complete before inter-RAT handover process is complete. Thus, core network initializes the release. (2) When inter-RAT handover prepare process is performed, an MS hangs up the call. Thus, core network initializes the release. Although the previous inter-RAT handover processes are incomplete, they are normal nested processes. (5) CS_INTERRAT_HO_PREP_FAIL_NO_RSRC_AVAIL CS inter-RAT handover prepare failure is caused by No Resource Available (cause value) because the data configuration of MSC is incorrect or there is no available resource in BSC. To locate the problem, track the signaling of core network and BSS for further analysis. (6) CS_INTERRAT_HO_PREP_FAIL_UNKNOWTARGETAug. 10, 2005 Confidential Information of Huawei Page 28 of 46 No Spreading Without Permission
  29. 29. UTRAN KPI Analysis Guide For Internal Use Only CS inter-RAT handover prepare failure is caused by Unknown Target RNC (cause value) because the data configuration of MSC is incorrect or the LAC of target cell is not configured. To locate the problem, check whether any data is incorrectly configured in the core network. This problem frequently occurs if a 2G network is adjusted. (7) CS_INTERRAT_HO_PREP_FAIL_ REQINFNOTAVAI CS inter-RAT handover prepare failure is caused by Requested Information Not Available because the data configuration is incorrect or target BSC does not support the handover. To locate the problem, track the signaling of core network and BSS for further analysis. (8) CS_INTERRAT_HO_PREP_FAIL_NO_RSP CS inter-RAT handover prepare failure occurs because core network does not respond to the handover prepare request. This may be caused by incorrect data configuration or link connection of core network. To locate the problem, track the signaling of core network and BSS for further analysis.4.3.3 CS Inter-RAT Handover Failure Analysis In the CS Inter-RAT Handover Analysis, start CS Inter-RAT Handover Failure Analysis to display the CS inter-RAT handover details (including CS inter-RAT handover success and failure rates), as shown in Figure 1-20. 0 CS_INTRAT_HO_OUT_FAIL_UNSPEC 0 CS_INTRAT_HO_OUT_FAIL_NO_RSP 12 CS_INTRAT_HO_OUT_FAIL_RELOC_ABORT 1 CS_INTRAT_HO_FAIL_OTHER 2,735 CS_INTRAT_HO_OUT_SUCC 0 CS_INTRAT_HO_OUT_FAIL_CFG_UNSUPP 27 CS_INTRAT_HO_OUT_FAIL_PHYCH_FAIL 0.43 % 0.04 % 98.56 % 0% 0% 0% % 0.97 Figure 1-20 CS inter-RAT handover failure analysisAug. 10, 2005 Confidential Information of Huawei Page 29 of 46 No Spreading Without Permission
  30. 30. UTRAN KPI Analysis Guide For Internal Use Only CS inter-RAT handover failure may be caused by the following reasons: (1) CS_INTERRAT_HO_ FAIL_UNSPEC CS inter-RAT handover failure is caused by Unspecified (cause value). This reason seldom occurs in a network. (2) CS_INTERRAT_HO_ FAIL_PHYCN_FAIL CS inter-RAT handover failure is caused by Physical Channel Failure (cause value). CS inter-RAT handover failure is mainly caused by:  The signals of 2G network are weak or UE fails to access the network due to serious interference.  Some parameters (such as ciphering mode) transmitted to UE are inconsistent with that of BSC. To locate the problem, compare the parameters of UE with that of BSC. (3) CS_INTERRAT_HO_ FAIL_ CFG_UNSUPP CS inter-RAT handover failure is caused by Configuration Unsupported (cause value) because UE does not support the handover request. This reason may be mainly caused by abnormal UE. (4) CS_INTERRAT_HO_ FAIL_ RELOC_ABORT After sending the handover request message to UE, RNC receives the release message from core network. However, the cause is not Normal Release because the link is released abnormally due to other reasons. This reason is caused by the nesting of handover process and release process. (5) CS_INTERRAT_HO_ FAIL_NO_RSP After RNC sends the handover request message to UE, UE does not acknowledge the request because network coverage is poor. (6) CS_INTERRAT_HO_ FAIL_OTHER CS inter-RAT handover failure is caused by other reasons. To locate the problem, analyze the RNC logs.Aug. 10, 2005 Confidential Information of Huawei Page 30 of 46 No Spreading Without Permission
  31. 31. UTRAN KPI Analysis Guide For Internal Use Only4.3.4 Cell Inter-RAT Handover Analysis In the CS inter-RAT Handover Analysis, start Cell inter-RAT Handover Analysis to query the TOPN. The queried results are outputted to list: (1) The cell that have the lowest CS inter-RAT handover success rate (2) The cell that have the greatest CS inter-RAT handover prepare failure times (3) The cell that have the greatest CS inter-RAT handover failure times (4) The cell that have the greatest CS inter-RAT handover times Through the previous results, you can find the cell that has the greatest CS inter- RAT handover times. Thus, the network coverage must be improved. In addition, you can find the cell that has the greatest CS inter-RAT handover failure times. Thus, the data configuration must be checked.4.4 PS Inter-RAT Handover Analysis This section consists of the following parts:  Overview  PS Inter-RAT Handover Failure Analysis  Cell Inter-RAT Handover Analysis4.4.1 Overview PS inter-RAT Handover Analysis is included in Nastar tasks. Double click PS Inter-RAT Handover Analysis to display the PS inter-RAT handover details between a 2G network and a 3G network, as shown in Figure 1-21. PS inter-RAT handover from a 2G network to a 3G network need not be analyzed because PS inter-RAT handover from a 2G network to a 3G network cannot be identified in access network.Aug. 10, 2005 Confidential Information of Huawei Page 31 of 46 No Spreading Without Permission
  32. 32. UTRAN KPI Analysis Guide For Internal Use Only 10 PS_INTRAT_HO_OUT_UTRAN_REQ 0 PS_INTRAT_HO_OUT_UE_REQ 100 % 0% Figure 1-21 PS inter-RAT handover analysis Figure 1-22 shows PS_INTRAT_HO_OUT_UTRAN_REQ and PS_INTRAT_HO_OUT_UTRAN_UE. PS_INTRAT_HO_OUT_UTRAN_REQ indicates that the PS inter-RAT handover is initialized by the UE in a dedicated channel. PS_INTRAT_HO_OUT_UTRAN_UE indicates that the PS inter-RAT handover is initialized by combined services or the PS inter-RAT reselection is initialized by the UE that is not in a dedicated channel. 0.9 0.8 0.7 0.6 Bar Value 0.5 0.4 0.3 0.2 0.1 0 0 Time b c d e f g RNC:41(ID:41)-PS_INTRAT_HO_OUT_UTRAN_SUCC_RATE b c d e f g RNC:41(ID:41)-PS_INTRAT_HO_OUT_UE_SUCC_RATE Figure 1-22 PS inter-RAT handover success rate4.4.2 PS Inter-RAT Handover Failure Analysis In the PS inter-RAT Handover Analysis, start PS inter-RAT Handover FailureAug. 10, 2005 Confidential Information of Huawei Page 32 of 46 No Spreading Without Permission
  33. 33. UTRAN KPI Analysis Guide For Internal Use Only Analysis to display the PS inter-RAT handover success and failure rates, as shown in Figure 1-23. 8 PS_INTRAT_HO_OUT_UTRAN_SUCC 0 PS_HO_OUT_FAIL_CFG_UNSUPP 0 PS_HO_OUT_FAIL_PHYCH_FAIL 80 % 0 PS_HO_OUT_FAIL_UNSPEC 0 PS_HO_OUT_FAIL_NO_RSP 2 PS_HO_OUT_FAIL_OTHER 20 % 0% 0% Figure 1-23 PS inter-RAT handover failure analysis PS inter-RAT handover failure may be caused by the following reasons: (1) PS_INTERRAT_HO_ FAIL_UNSPEC PS inter-RAT handover failure is caused by Unspecified (cause value). This reason seldom occurs in a network. (2) PS_INTERRAT_HO_ FAIL_PHYCN_FAIL PS inter-RAT handover failure is caused by Physical Channel Failure (cause value) because the signals of 2G network are weak or UE fails to access the network due to serious interference. (3) PS_INTERRAT_HO_ FAIL_ CFG_UNSUPP PS inter-RAT handover failure is caused by Configuration Unsupported (cause value) because UE does not support the handover request. This reason may be mainly caused by abnormal UE. (4) PS_INTERRAT_HO_ FAIL_NO_RSP After RNC sends the handover request message to UE, UE does not acknowledge the request because network coverage is poor or UE does not support the handover.Aug. 10, 2005 Confidential Information of Huawei Page 33 of 46 No Spreading Without Permission
  34. 34. UTRAN KPI Analysis Guide For Internal Use Only (5) PS_INTERRAT_HO_ FAIL_OTHER PS inter-RAT handover failure is caused by other reasons. To locate the problem, analyze the RNC logs.4.4.3 Cell Inter-RAT Handover Analysis In the PS Inter-RAT Handover Analysis, start Cell Inter-RAT Handover Analysis to query the TOPN. The queried results are outputted to list: (1) The cell that have the lowest PS inter-RAT handover success rate (2) The cell that have the greatest PS inter-RAT handover prepare failure times (3) The cell that have the greatest PS inter-RAT handover failure times (4) The cell that have the greatest PS inter-RAT handover times Through the previous results, you can find the cell that has the greatest PS inter- RAT handover times. Thus, the network coverage must be improved.4.5 Cell Update Analysis This section consists of the following parts:  Overview  Cell Update Failure Analysis4.5.1 Overview Cell Update Analysis is included in Nastar tasks. Double click Cell Update Analysis to display the cell update details (including cell update times and cell update success rate). Cell update process is initialized because the links of UE are abnormal or RLC is reset. Cell update process is mainly caused by poor network coverage. This cell update process is different from that of cell reselection, so you must be familiar with diverse cell update processes. In the Cell Update Analysis, start Cell Update Scenario Analysis to display different cell update scenarios, as shown in Figure 1-24. If the state transition is disabled in a network, the cell update is caused by abnormal links or RLC reset if UE is notAug. 10, 2005 Confidential Information of Huawei Page 34 of 46 No Spreading Without Permission
  35. 35. UTRAN KPI Analysis Guide For Internal Use Only in CELL_FACH or CELL_PCH state. 0 CELL_UPDT_REENTER 0 CELL_UPDT_PAGE 0 CELL_UPDT_UL_DATA_TRANS 211 CELL_UPDT_RLC_ERR 15 CELL_UPDT_RL_FAIL 0 CELL_UPDT_PRD 0 CELL_UPDT_RESEL 93.36 % 0 CELL_UPDT_OTHER 0% 0% 6.64 % Figure 1-24 Cell update scenarios In the Cell Update Scenario Analysis, click Create a Bar Chart to display the cell update success rates, as shown in Figure 1-25. In general, the cell updates are caused by abnormal links (RL) or RLC reset (RLC_ERR), thus low cell update success rate may be caused by poor network coverage. If cell update is caused by other reasons, cell update success rate must be greater than 85%. 0.07 0.06 0.05 Bar Value 0.04 0.03 0.02 0.01 0 0 Time b c d e f g RNC:41(ID:41)-CELL_UPDT_SUCC_RATE_RESEL b c d e f g RNC:41(ID:41)-CELL_UPDT_SUCC_RATE_REENTER b c d e f g RNC:41(ID:41)-CELL_UPDT_SUCC_RATE_PAGE b c d e f g RNC:41(ID:41)-CELL_UPDT_SUCC_RATE_UL_DATA_TRANS b c d e f g RNC:41(ID:41)-CELL_UPDT_SUCC_RATE_RLC_ERR b c d e f g RNC:41(ID:41)-CELL_UPDT_SUCC_RATE_RL b c d e f g RNC:41(ID:41)-CELL_UPDT_SUCC_RATE_PRD b c d e f g RNC:41(ID:41)-CELL_UPDT_SUCC_RATE_OTHER Figure 1-25 Cell update success ratesAug. 10, 2005 Confidential Information of Huawei Page 35 of 46 No Spreading Without Permission
  36. 36. UTRAN KPI Analysis Guide For Internal Use Only4.5.2 Cell Update Failure Analysis In the Cell Update Analysis, start Cell Update Analysis to query the TOPN. The queried results are outputted to list: (1) The cell that has the lowest cell update success rate (2) The cell that has the greatest cell update failure times If a cell has the lowest cell update success rate, cell update times are less. Attention must be paid to the cell that has the greatest cell update failure times. In the queried results of Cell Update Analysis, start Cell Update Scenario Analysis for Cell to analyze the cell update failure and summarize the cell update failure scenarios.4.6 Call Drop Analysis This section consists of the following parts:  Overview  CS Call Drop Analysis  PS Call Drop Analysis  Cell Call Drop Analysis4.6.1 Overview Call Drop Analysis is included in Nastar tasks. Double click Call Drop Analysis to display the RNC call drop details. Then, click Create a Pie Chart to display the call drop details for different services (including voice, VP, CS, and PS), as shown in Figure 1-27.Aug. 10, 2005 Confidential Information of Huawei Page 36 of 46 No Spreading Without Permission
  37. 37. UTRAN KPI Analysis Guide For Internal Use Only 0% 75 RNC_CS_RAB_REL_AMR_TRIG_BY_RNC 1.34 % 8 RNC_CS_RAB_REL_CONV_64K_TRIG_BY_RNC 0 RNC_CS_RAB_REL_STR_TRIG_BY_RNC 515 RNC_PS_RAB_REL_REQ 12.54 % 86.12 % Figure 1-26 Call drop analysis In the Cell Drop Analysis, click Create a Bar Chart to display the call drop rates for different services (including voice, VP, CS, and PS), as shown in Figure 1-27. In general, the call drop rate of CS service is less than that of VP service or PS service because of their different service coverage capabilities and service process complexities, especially in the poor-covered areas. 0.65 0.6 0.55 0.5 0.45 Bar Value 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 0 Time b c d e f g RNC:41(ID:41)-CS_RAB_AMR_DROP_RATE g b c d e f RNC:41(ID:41)-CS_RAB_VP_DROP_RATE b c d e f g RNC:41(ID:41)-CS_RAB_STR_DROP_RATE g b c d e f RNC:41(ID:41)-PS_RAB_DROP_RATE Figure 1-27 Call drop rates4.6.2 CS Call Drop Analysis In the CS Call Drop Analysis, click Create a Pie Chart to display the CS call drop reasons, as shown in Figure 1-28.Aug. 10, 2005 Confidential Information of Huawei Page 37 of 46 No Spreading Without Permission
  38. 38. UTRAN KPI Analysis Guide For Internal Use Only 0% 75 RNC_CS_RAB_REL_AMR_TRIG_BY_RNC 1.34 % 8 RNC_CS_RAB_REL_CONV_64K_TRIG_BY_RNC 0 RNC_CS_RAB_REL_STR_TRIG_BY_RNC 515 RNC_PS_RAB_REL_REQ 12.54 % 86.12 % Figure 1-28 CS call drop reasons CS call drops may be caused by the following reasons: (1) RAB_CS_REL_RF_LOSS CS call drop may be caused by abnormal release caused by the lost synchronization of links because of poor network coverage (including adjacent cell missing, small handover area. As a result, UE closes the transmitter abnormally or uplink demodulation is asynchronous. To solve the problem, network coverage must be improved. In the early network, call drops are mainly caused by this reason. (2) RNC_CS_RAB_REL_TRIG_BY_RNC_SRB_RESET CS call drops may be caused by link releasing due to downlink SRB reset. This reason is mainly caused by poor network coverage (including adjacent cell missing and small handover area). To solve the problem, the network coverage must be improved. In the early network, call drops are mainly caused by this reason. (3) RNC_CS_RAB_REL_TRIG_BY_RNC_AAL2_LOSS If IU CS interface (AAL2 path) is abnormal, RNC initializes the release. In practice, this reason seldom occurs. If this reason occurs, the problem may be caused by any faulty or defective equipment. In some versions of RNC, normal release is recorded as abnormal release during the RB setup process.Aug. 10, 2005 Confidential Information of Huawei Page 38 of 46 No Spreading Without Permission

×