This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Contents
1. CALL DROP DEFINITION and MEASUREMENT POINTS ............................................................................................................ 2
2. CALL DROP COUNTERS ................................................................................................................................................................ 3
2.1 CALL DROP COUNTERS RELATIONS ....................................................................................................................................... 3
2.2 CALL DROP COUNTERS DEFINITIONS .................................................................................................................................... 4
2.3 CALL DROP COUNTERS INCREMENT LOGIC .......................................................................................................................... 4
3. CALL DROP TROUBLESHOOTING ................................................................................................................................................. 5
3.1 CALL DROP CAUSE ANALYSIS ................................................................................................................................................ 5
3.2 CALL DROP REASONS for GENERAL CALL DROP TYPES ......................................................................................................... 6
3.3 TROUBLESHOOT STEPS FOR CALL DROP ............................................................................................................................... 6
Sum of CM33:Call Drops on Traffic Channel(times) 16135 100,0
Sum of CM33C:Call Drops on Radio Interface (Traffic Channel)(times) 16081 100,0 99,7
Sum of CM330:Call Drops on Radio Interface in Stable State (Traffic Channel)(times) 14505 100,0 90,2
Sum of CM3300:Call Drops on Traffic Channel in Stable State (Error Indication)(times) 4947 100,0 34,1
Sum of M3100A:Cal l Drops due to ERR IND Received on TCHF (Traffic Channel ) in Stable State (T200 Expired)(times) 4554 92,1
Sum of M3100B:Cal l Drops due to ERR IND Received on TCHF (Traffic Channel ) in Stable State (Unsol ici ted DM Response)(times) 0 0,0
Sum of M3100C:Cal l Drops due to ERR IND Received on TCHF (Traffic Channel ) in Stable State (Sequence Error)(times) 1 0,0
Sum of M3200A:Cal l Drops due to ERR IND Received on TCHH (Traffic Channel ) in Stable State (T200 Expired)(times) 392 7,9
Sum of M3200B:Cal l Drops due to ERR IND Received on TCHH (Traffic Channel ) in Stable State (Unsol ici ted DM Response)(times) 0 0,0
Sum of M3200C:Cal l Drops due to ERR IND Received on TCHH (Traffic Channel ) in Stable State (Sequence Error)(times) 0 0,0
Sum of CM3301:Call Drops on Traffic Channel in Stable State (Connection Failure)(times) 9553 100,0 65,9
Sum of M3101A:Cal l Drops due to CONN FAIL Received on TCHF (Traffic Channel ) in Stable State (Radio Link Fa i lure)(times) 9079 95,0
Sum of M3101B:Cal l Drops due to CONN FAIL Received on TCHF (Traffic Channel ) in Stable State (HO Access Fa i lure)(times) 6 0,1
Sum of M3101C:Cal l Drops due to CONN FAIL Received on TCHF (Traffic Channel ) in Stable State (OM Intervention)(times) 0 0,0
Sum of M3101D:Cal l Drops due to CONN FAIL Received on TCHF (Traffic Channel ) in Stable State (Radio Resource Unavai lable)(times) 0 0,0
Sum of M3101E:Cal l Drops due to CONN FAIL Received on TCHF (Traffic Channel ) in Stable State (Other Causes)(times) 0 0,0
Sum of M3201A:Cal l Drops due to CONN FAIL Received on TCHH (Traffic Channel ) in Stable State (Radio Link Fa i lure)(times) 468 4,9
Sum of M3201B:Cal l Drops due to CONN FAIL Received on TCHH (Traffic Channel ) in Stable State (HO Access Fa i lure)(times) 0 0,0
Sum of M3201C:Cal l Drops due to CONN FAIL Received on TCHH (Traffic Channel ) in Stable State (OM Intervention)(times) 0 0,0
Sum of M3201D:Cal l Drops due to CONN FAIL Received on TCHH (Traffic Channel ) in Stable State (Radio Resource Unavai lable)(times) 0 0,0
Sum of M3201E:Cal l Drops due to CONN FAIL Received on TCHH (Traffic Channel ) in Stable State (Other Causes)(times) 0 0,0
Sum of CM3302:Call Drops on Traffic Channel in Stable State (Release Indication)(times) 5 100,0 0,0
Sum of M3102:Cal l Drops due to REL IND Received on TCHF (Traffic Channel )(times) 5 100,0
Sum of M3202:Cal l Drops due to REL IND Received on TCHH (Traffic Channel )(times) 0 0,0
Sum of CM331:Call Drops on Radio Interface in Handover State (Traffic Channel)(times) 1576 100,0 9,8
Sum of H3027Ca:Fa i led Internal Intra-Cel l Handovers (Timer Expired) (TCHF) (Traffic Channel )(times) 1 0,1
Sum of H3028Ca:Fa i led Internal Intra-Cel l Handovers (Timer Expired) (TCHH) (Traffic Channel )(times) 4 0,3
Sum of H3127Ca:Fa i led Outgoing Internal Inter-Cel l Handovers (Timer Expired) (TCHF) (Traffic Channel )(times) 1472 93,4
Sum of H3128Ca:Fa i led Outgoing Internal Inter-Cel l Handovers (Timer Expired) (TCHH) (Traffic Channel )(times) 97 6,2
Sum of H3327Ca:Fa i led Outgoing External Inter-Cel l Handovers (T8 Expired) (TCHF) (Traffic Channel )(times) 2 0,1
Sum of H3328Ca:Fa i led Outgoing External Inter-Cel l Handovers (T8 Expired) (TCHH) (Traffic Channel )(times) 0 0,0
Sum of CM332:Call Drops due to No MRs from MS for a Long Time (Traffic Channel)(times) 2 0,0
Sum of CM333:Call Drops due to Abis Terrestrial Link Failure (Traffic Channel)(times) 0 0,0
Sum of CM334:Call Drops due to Equipment Failure (Traffic Channel)(times) 45 0,3
Sum of CM335:Call Drops due to Forced Handover (Traffic Channel)(times) 7 0,0
3.2 CALL DROP REASONS for GENERAL CALL DROP TYPES
Other drops like Abis Terrestrial Link Failure drop caused by Transmission Link broken, Equipment Failure drops caused by
HW problems and Forced Handover drops caused by OM Intervention. These drops should be handled by separately.
For these two general drop cause Radio Link Timeout and T200 Expired, the reasons are;
Coverage gaps,
Quality or Interference problems,
Unbalanced Path Losses,
HW Fault or Installation faults,
Parameter definition and OSS problems,
Missing Neighbor Relations.
Also for other big percent of drop cause Failed Outgoing Internal Inter-Cell Handovers (Timer Expired), the reasons are;
Wrong or missing neighbor definitions,
Wrong cell to cell neighbor parameters or timers,
Coverage gaps,
Quality or Interference problems,
HW Faults or Installation faults.
3.3 TROUBLESHOOT STEPS FOR CALL DROP
3.3.1 PARAMETER PROBLEMS
First of all for a proHleマatiI Iell, ┘e should IheIk geミeral paraマeters of this Iell aミd also this Iell’s ミeighHor Iells.
Cells general parameters like;
In Basic Attributes Parameter set;
LAC, Layer of Cell, Cell Priority, Cell Extension Type, Cell IUO Type, MAX TA, RXLEV_ACCESS_MIN, TCH/F Uplink DTX, TCH/H
Uplink DTX, Encryption Algorithm, UL PC Allowed, DL PC Allowed, Direct Retry, TCH/F Use Downlink DTX, TCH/H Downlink
DTX should be checked. These would affect general quality of serving cell.
If cell is a border cell or have external definitions in other BSCs or RNCs. All external definitions should be checked also.
In Idle Mode Parameter set;
BS-PA-MFRAMS, T3212, CRH, PI, CRO, TO, PT, NCC Permitted should be checked. These would affect service area of cell.
In Other Attributes Parameter set;
MS_TXPWR_MAX_CCH, STIRC Allowed, T3101, T3103A, T3103C, T7, T3107, T3121, T8, T3109, T3111, T3122 should be
checked. These would affect general quality of serving cell.
In Call Control Parameter set;
Paging Times, MS MAX Retrans, SACCH Multi-Frames, AFR SACCH Multi-Frames, AHR SACCH Multi-Frames, AFR Radio Link
Timeout, AHR Radio Link Timeout, Radio Link Timeout, T200 SDCCH, T200 FACCH/F, T200 FACCH/H, T200 SACCH TCH SAPI0,
T200 SACCH TCH SAPI3, T200 SACCH SDCCH, T200 SDCCH SAPI3, Use LAPDm N200, N200 of Establish, N200 of Release, N200
COUNTER NUMBER COUNTER NAME
S462A Number of MRs (Uplink-and-Downlink Balance Level = 1)(times)
S462B Number of MRs (Uplink-and-Downlink Balance Level = 2)(times)
S462C Number of MRs (Uplink-and-Downlink Balance Level = 3)(times)
S462D Number of MRs (Uplink-and-Downlink Balance Level = 4)(times)
S462E Number of MRs (Uplink-and-Downlink Balance Level = 5)(times)
S462F Number of MRs (Uplink-and-Downlink Balance Level = 6)(times)
S462G Number of MRs (Uplink-and-Downlink Balance Level = 7)(times)
S462H Number of MRs (Uplink-and-Downlink Balance Level = 8)(times)
S462I Number of MRs (Uplink-and-Downlink Balance Level = 9)(times)
S462J Number of MRs (Uplink-and-Downlink Balance Level = 10)(times)
S462K Number of MRs (Uplink-and-Downlink Balance Level = 11)(times)
of SACCH, N200 of SDCCH, N200 of FACH/Half rate, N200 of FACCH/Full rate should be checked. These would affect deciding
time of drop events.
In Handover Data Parameter set;
Pathloss Ho. Enable, Co-BSC/MSC Adj, Intracell HO Allowed, Intracell F-H HO Allowed, Load HO Allowed, MS Fast Moving HO
Allowed, Rx_Level_Drop HO Allowed, PBGT HO Allowed, Level HO Allowed, Fringe HO Allowed, BQ HO Allowed, TA HO
Allowed, Concentric Circles HO Allowed, Interference HO Allowed, Quick Handover Enable, UtoO Traffic HO Allowed, Penalty
Allowed, MR.Preprocessing, No Dl Mr.HO Allowed should be checked. These would affect HO performance and decision of
serving cell.
Also the parameters related with Watch Time/Valid Time should be checked. These would affect deciding faster or slower of
HO.
Also Cell to Cell neighbor definitions should be checked. Timer, hysteresis and thresholds between cells would affect HO
performance between these cells.
3.3.2 PATH BALANCE PROBLEMS
Path Balance is a statistic
considering Uplink Path Loss and
Downlink Path Loss. It is TRX based,
so we could see unbalanced TRX or
have an opinion about feeder
connections. On left these counters
are shown.
Formula is UL Path Loss- DL Path Loss. By counter meaning, さ6ざ means difference is zero. So it is expected to be all samples in
さ6ざ ideally. More samples less than さ3ざ means there is a DL Path Loss problem more samples greater than さ8ざ means there is
a UL Path Loss problem.
These differences generally points out;
HW Problems,
TRX Power parameters differences,
Cross-connections of feeder between sectors,
RXU definitions, Send mode and Receive mode definitions problems.
You should keep in mind that, if there is a TMA installation in sector path balance would shift to さ1ざ or in use of PBT (Power
Boost Technology) path balance would shift to さ11ざ because of power changes.
Also if there is a Power difference between TRXs of cells, it would affect path balance. In TRX definitions;
Power Level,
Power Fine Tune,
Power Type parameters would decide maximum TRX output power.
COUNTER NUMBER COUNTER NAME
S4400A Number of MRs (TA = 0)(times)
S4401A Number of MRs (TA = 1)(times)
S4402A Number of MRs (TA = 2)(times)
S4403A Number of MRs (TA = 3)(times)
S4404A Number of MRs (TA = 4)(times)
S4405A Number of MRs (TA = 5)(times)
S4406A Number of MRs (TA = 6)(times)
S4407A Number of MRs (TA = 7)(times)
S4408A Number of MRs (TA = 8)(times)
S4409A Number of MRs (TA = 9)(times)
S4410A Number of MRs (TA = 10)(times)
S4411A Number of MRs (TA = 11)(times)
S4412A Number of MRs (TA = 12)(times)
S4413A Number of MRs (TA = 13)(times)
S4414A Number of MRs (TA = 14)(times)
S4415A Number of MRs (TA = 15)(times)
S4416A Number of MRs (TA = 16)(times)
S4417A Number of MRs (TA = 17)(times)
S4418A Number of MRs (TA = 18)(times)
S4419A Number of MRs (TA = 19)(times)
S4420A Number of MRs (TA = 20)(times)
S4421A Number of MRs (TA = 21)(times)
S4422A Number of MRs (TA = 22)(times)
S4423A Number of MRs (TA = 23)(times)
S4424A Number of MRs (TA = 24)(times)
S4425A Number of MRs (TA = 25)(times)
S4426A Number of MRs (TA = 26)(times)
S4427A Number of MRs (TA = 27)(times)
S4428A Number of MRs (TA = 28)(times)
S4429A Number of MRs (TA = 29)(times)
S4430A Number of MRs (TA = 30 or 31)(times)
S4432A Number of MRs (TA = 32 or 33)(times)
S4434A Number of MRs (TA = 34 or 35)(times)
S4436A Number of MRs (TA = 36 or 37)(times)
S4438A Number of MRs (TA = 38 or 39)(times)
S4440A Number of MRs (TA = 40 to 44)(times)
S4445A Number of MRs (TA = 45 to 49)(times)
S4450A Number of MRs (TA = 50 to 54)(times)
S4455A Number of MRs (TA = 55 to 63)(times)
S4463A Number of MRs (TA greater than 63)(times)
There are sample stats of TRX based path balance statistic.
As seen on the left for TRX-
1343 there is a Uplink path loss
problem. HW Check should be
done.
3.3.3 COVERAGE GAPS PROBLEMS
For finding coverage gaps;
ざNuマHers of MRs Hased oミ TA per TRXざ, さRadio Liミk Failure Measureマeミt Hased oミ TA per TRXざ, さTCHF ReIei┗e Le┗el Measureマeミt per TRXざ, さTCHH ReIei┗e Le┗el Measureマeミt per TRXざ マeasureマeミt sets should He used.
さNuマHers of MRs Hased oミ TA per TRXざ Iouミters are sho┘ミ Helo┘;
These counters are MR samples in each TA based on TRX.
COUNTER NUMBER COUNTER NAME
S4400B Radio Link Fa i lures (TA = 0)(times)
S4401B Radio Link Fa i lures (TA = 1)(times)
S4402B Radio Link Fa i lures (TA = 2)(times)
S4403B Radio Link Fa i lures (TA = 3)(times)
S4404B Radio Link Fa i lures (TA = 4)(times)
S4405B Radio Link Fa i lures (TA = 5)(times)
S4406B Radio Link Fa i lures (TA = 6)(times)
S4407B Radio Link Fa i lures (TA = 7)(times)
S4408B Radio Link Fa i lures (TA = 8)(times)
S4409B Radio Link Fa i lures (TA = 9)(times)
S4410B Radio Link Fa i lures (TA = 10)(times)
S4411B Radio Link Fa i lures (TA = 11)(times)
S4412B Radio Link Fa i lures (TA = 12)(times)
S4413B Radio Link Fa i lures (TA = 13)(times)
S4414B Radio Link Fa i lures (TA = 14)(times)
S4415B Radio Link Fa i lures (TA = 15)(times)
S4416B Radio Link Fa i lures (TA = 16)(times)
S4417B Radio Link Fa i lures (TA = 17)(times)
S4418B Radio Link Fa i lures (TA = 18)(times)
S4419B Radio Link Fa i lures (TA = 19)(times)
S4420B Radio Link Fa i lures (TA = 20)(times)
S4421B Radio Link Fa i lures (TA = 21)(times)
S4422B Radio Link Fa i lures (TA = 22)(times)
S4423B Radio Link Fa i lures (TA = 23)(times)
S4424B Radio Link Fa i lures (TA = 24)(times)
S4425B Radio Link Fa i lures (TA = 25)(times)
S4426B Radio Link Fa i lures (TA = 26)(times)
S4427B Radio Link Fa i lures (TA = 27)(times)
S4428B Radio Link Fa i lures (TA = 28)(times)
S4429B Radio Link Fa i lures (TA = 29)(times)
S4430B Radio Link Fa i lures (TA = 30 or 31)(times)
S4432B Radio Link Fa i lures (TA = 32 or 33)(times)
S4434B Radio Link Fa i lures (TA = 34 or 35)(times)
S4436B Radio Link Fa i lures (TA = 36 or 37)(times)
S4438B Radio Link Fa i lures (TA = 38 or 39)(times)
S4440B Radio Link Fa i lures (TA = 40 to 44)(times)
S4445B Radio Link Fa i lures (TA = 45 to 49)(times)
S4450B Radio Link Fa i lures (TA = 50 to 54)(times)
S4455B Radio Link Fa i lures (TA = 55 to 63)(times)
S4463B Radio Link Fa i lures (TA greater than 63)(times)
As seen in below graph, cells have some overshooting and coverage gaps.
さRadio Liミk Failure Measureマeミt Hased oミ TA per TRXざ Iouミters are shown on the left;
Froマ さRadio Liミk Failure Measureマeミt Hased oミ TA per TRXざ Iouミters, ┞ou ┘ould ha┗e aミ idea of ┘here Iells drop generally
occurs. If it is gathered to one TA, it could be said that in that TA area there is a coverage problem.
さTCHF ReIei┗e Le┗el Measureマeミt per TRX ざ Iouミters are sho┘ミ Helo┘. There are ヱヲ8 Iouミter for each RxLevel between 0-
7 (-110 dBm—47 dBm), RxQuality between 0-7.
COUNTER NUMBER COUNTER NAME COUNTER NUMBER COUNTER NAME
S4100B Number of MRs on Downlink TCHF (Receive Level Rank 0 and Receive Quality Rank 0)(times) S4100A Number of MRs on Uplink TCHF (Receive Level Rank 0 and Receive Quality Rank 0)(times)
S4101B Number of MRs on Downlink TCHF (Receive Level Rank 0 and Receive Quality Rank 1)(times) S4101A Number of MRs on Uplink TCHF (Receive Level Rank 0 and Receive Quality Rank 1)(times)
S4102B Number of MRs on Downlink TCHF (Receive Level Rank 0 and Receive Quality Rank 2)(times) S4102A Number of MRs on Uplink TCHF (Receive Level Rank 0 and Receive Quality Rank 2)(times)
S4103B Number of MRs on Downlink TCHF (Receive Level Rank 0 and Receive Quality Rank 3)(times) S4103A Number of MRs on Uplink TCHF (Receive Level Rank 0 and Receive Quality Rank 3)(times)
S4104B Number of MRs on Downlink TCHF (Receive Level Rank 0 and Receive Quality Rank 4)(times) S4104A Number of MRs on Uplink TCHF (Receive Level Rank 0 and Receive Quality Rank 4)(times)
S4105B Number of MRs on Downlink TCHF (Receive Level Rank 0 and Receive Quality Rank 5)(times) S4105A Number of MRs on Uplink TCHF (Receive Level Rank 0 and Receive Quality Rank 5)(times)
S4106B Number of MRs on Downlink TCHF (Receive Level Rank 0 and Receive Quality Rank 6)(times) S4106A Number of MRs on Uplink TCHF (Receive Level Rank 0 and Receive Quality Rank 6)(times)
S4107B Number of MRs on Downlink TCHF (Receive Level Rank 0 and Receive Quality Rank 7)(times) S4107A Number of MRs on Uplink TCHF (Receive Level Rank 0 and Receive Quality Rank 7)(times)
S4110B Number of MRs on Downlink TCHF (Receive Level Rank 1 and Receive Quality Rank 0)(times) S4110A Number of MRs on Uplink TCHF (Receive Level Rank 1 and Receive Quality Rank 0)(times)
S4111B Number of MRs on Downlink TCHF (Receive Level Rank 1 and Receive Quality Rank 1)(times) S4111A Number of MRs on Uplink TCHF (Receive Level Rank 1 and Receive Quality Rank 1)(times)
S4112B Number of MRs on Downlink TCHF (Receive Level Rank 1 and Receive Quality Rank 2)(times) S4112A Number of MRs on Uplink TCHF (Receive Level Rank 1 and Receive Quality Rank 2)(times)
S4113B Number of MRs on Downlink TCHF (Receive Level Rank 1 and Receive Quality Rank 3)(times) S4113A Number of MRs on Uplink TCHF (Receive Level Rank 1 and Receive Quality Rank 3)(times)
S4114B Number of MRs on Downlink TCHF (Receive Level Rank 1 and Receive Quality Rank 4)(times) S4114A Number of MRs on Uplink TCHF (Receive Level Rank 1 and Receive Quality Rank 4)(times)
S4115B Number of MRs on Downlink TCHF (Receive Level Rank 1 and Receive Quality Rank 5)(times) S4115A Number of MRs on Uplink TCHF (Receive Level Rank 1 and Receive Quality Rank 5)(times)
S4116B Number of MRs on Downlink TCHF (Receive Level Rank 1 and Receive Quality Rank 6)(times) S4116A Number of MRs on Uplink TCHF (Receive Level Rank 1 and Receive Quality Rank 6)(times)
S4117B Number of MRs on Downlink TCHF (Receive Level Rank 1 and Receive Quality Rank 7)(times) S4117A Number of MRs on Uplink TCHF (Receive Level Rank 1 and Receive Quality Rank 7)(times)
S4120B Number of MRs on Downlink TCHF (Receive Level Rank 2 and Receive Quality Rank 0)(times) S4120A Number of MRs on Uplink TCHF (Receive Level Rank 2 and Receive Quality Rank 0)(times)
S4121B Number of MRs on Downlink TCHF (Receive Level Rank 2 and Receive Quality Rank 1)(times) S4121A Number of MRs on Uplink TCHF (Receive Level Rank 2 and Receive Quality Rank 1)(times)
S4122B Number of MRs on Downlink TCHF (Receive Level Rank 2 and Receive Quality Rank 2)(times) S4122A Number of MRs on Uplink TCHF (Receive Level Rank 2 and Receive Quality Rank 2)(times)
S4123B Number of MRs on Downlink TCHF (Receive Level Rank 2 and Receive Quality Rank 3)(times) S4123A Number of MRs on Uplink TCHF (Receive Level Rank 2 and Receive Quality Rank 3)(times)
S4124B Number of MRs on Downlink TCHF (Receive Level Rank 2 and Receive Quality Rank 4)(times) S4124A Number of MRs on Uplink TCHF (Receive Level Rank 2 and Receive Quality Rank 4)(times)
S4125B Number of MRs on Downlink TCHF (Receive Level Rank 2 and Receive Quality Rank 5)(times) S4125A Number of MRs on Uplink TCHF (Receive Level Rank 2 and Receive Quality Rank 5)(times)
S4126B Number of MRs on Downlink TCHF (Receive Level Rank 2 and Receive Quality Rank 6)(times) S4126A Number of MRs on Uplink TCHF (Receive Level Rank 2 and Receive Quality Rank 6)(times)
S4127B Number of MRs on Downlink TCHF (Receive Level Rank 2 and Receive Quality Rank 7)(times) S4127A Number of MRs on Uplink TCHF (Receive Level Rank 2 and Receive Quality Rank 7)(times)
S4130B Number of MRs on Downlink TCHF (Receive Level Rank 3 and Receive Quality Rank 0)(times) S4130A Number of MRs on Uplink TCHF (Receive Level Rank 3 and Receive Quality Rank 0)(times)
S4131B Number of MRs on Downlink TCHF (Receive Level Rank 3 and Receive Quality Rank 1)(times) S4131A Number of MRs on Uplink TCHF (Receive Level Rank 3 and Receive Quality Rank 1)(times)
S4132B Number of MRs on Downlink TCHF (Receive Level Rank 3 and Receive Quality Rank 2)(times) S4132A Number of MRs on Uplink TCHF (Receive Level Rank 3 and Receive Quality Rank 2)(times)
S4133B Number of MRs on Downlink TCHF (Receive Level Rank 3 and Receive Quality Rank 3)(times) S4133A Number of MRs on Uplink TCHF (Receive Level Rank 3 and Receive Quality Rank 3)(times)
S4134B Number of MRs on Downlink TCHF (Receive Level Rank 3 and Receive Quality Rank 4)(times) S4134A Number of MRs on Uplink TCHF (Receive Level Rank 3 and Receive Quality Rank 4)(times)
S4135B Number of MRs on Downlink TCHF (Receive Level Rank 3 and Receive Quality Rank 5)(times) S4135A Number of MRs on Uplink TCHF (Receive Level Rank 3 and Receive Quality Rank 5)(times)
S4136B Number of MRs on Downlink TCHF (Receive Level Rank 3 and Receive Quality Rank 6)(times) S4136A Number of MRs on Uplink TCHF (Receive Level Rank 3 and Receive Quality Rank 6)(times)
S4137B Number of MRs on Downlink TCHF (Receive Level Rank 3 and Receive Quality Rank 7)(times) S4137A Number of MRs on Uplink TCHF (Receive Level Rank 3 and Receive Quality Rank 7)(times)
S4140B Number of MRs on Downlink TCHF (Receive Level Rank 4 and Receive Quality Rank 0)(times) S4140A Number of MRs on Uplink TCHF (Receive Level Rank 4 and Receive Quality Rank 0)(times)
S4141B Number of MRs on Downlink TCHF (Receive Level Rank 4 and Receive Quality Rank 1)(times) S4141A Number of MRs on Uplink TCHF (Receive Level Rank 4 and Receive Quality Rank 1)(times)
S4142B Number of MRs on Downlink TCHF (Receive Level Rank 4 and Receive Quality Rank 2)(times) S4142A Number of MRs on Uplink TCHF (Receive Level Rank 4 and Receive Quality Rank 2)(times)
S4143B Number of MRs on Downlink TCHF (Receive Level Rank 4 and Receive Quality Rank 3)(times) S4143A Number of MRs on Uplink TCHF (Receive Level Rank 4 and Receive Quality Rank 3)(times)
S4144B Number of MRs on Downlink TCHF (Receive Level Rank 4 and Receive Quality Rank 4)(times) S4144A Number of MRs on Uplink TCHF (Receive Level Rank 4 and Receive Quality Rank 4)(times)
S4145B Number of MRs on Downlink TCHF (Receive Level Rank 4 and Receive Quality Rank 5)(times) S4145A Number of MRs on Uplink TCHF (Receive Level Rank 4 and Receive Quality Rank 5)(times)
S4146B Number of MRs on Downlink TCHF (Receive Level Rank 4 and Receive Quality Rank 6)(times) S4146A Number of MRs on Uplink TCHF (Receive Level Rank 4 and Receive Quality Rank 6)(times)
S4147B Number of MRs on Downlink TCHF (Receive Level Rank 4 and Receive Quality Rank 7)(times) S4147A Number of MRs on Uplink TCHF (Receive Level Rank 4 and Receive Quality Rank 7)(times)
S4150B Number of MRs on Downlink TCHF (Receive Level Rank 5 and Receive Quality Rank 0)(times) S4150A Number of MRs on Uplink TCHF (Receive Level Rank 5 and Receive Quality Rank 0)(times)
S4151B Number of MRs on Downlink TCHF (Receive Level Rank 5 and Receive Quality Rank 1)(times) S4151A Number of MRs on Uplink TCHF (Receive Level Rank 5 and Receive Quality Rank 1)(times)
S4152B Number of MRs on Downlink TCHF (Receive Level Rank 5 and Receive Quality Rank 2)(times) S4152A Number of MRs on Uplink TCHF (Receive Level Rank 5 and Receive Quality Rank 2)(times)
S4153B Number of MRs on Downlink TCHF (Receive Level Rank 5 and Receive Quality Rank 3)(times) S4153A Number of MRs on Uplink TCHF (Receive Level Rank 5 and Receive Quality Rank 3)(times)
S4154B Number of MRs on Downlink TCHF (Receive Level Rank 5 and Receive Quality Rank 4)(times) S4154A Number of MRs on Uplink TCHF (Receive Level Rank 5 and Receive Quality Rank 4)(times)
S4155B Number of MRs on Downlink TCHF (Receive Level Rank 5 and Receive Quality Rank 5)(times) S4155A Number of MRs on Uplink TCHF (Receive Level Rank 5 and Receive Quality Rank 5)(times)
S4156B Number of MRs on Downlink TCHF (Receive Level Rank 5 and Receive Quality Rank 6)(times) S4156A Number of MRs on Uplink TCHF (Receive Level Rank 5 and Receive Quality Rank 6)(times)
S4157B Number of MRs on Downlink TCHF (Receive Level Rank 5 and Receive Quality Rank 7)(times) S4157A Number of MRs on Uplink TCHF (Receive Level Rank 5 and Receive Quality Rank 7)(times)
S4160B Number of MRs on Downlink TCHF (Receive Level Rank 6 and Receive Quality Rank 0)(times) S4160A Number of MRs on Uplink TCHF (Receive Level Rank 6 and Receive Quality Rank 0)(times)
S4161B Number of MRs on Downlink TCHF (Receive Level Rank 6 and Receive Quality Rank 1)(times) S4161A Number of MRs on Uplink TCHF (Receive Level Rank 6 and Receive Quality Rank 1)(times)
S4162B Number of MRs on Downlink TCHF (Receive Level Rank 6 and Receive Quality Rank 2)(times) S4162A Number of MRs on Uplink TCHF (Receive Level Rank 6 and Receive Quality Rank 2)(times)
S4163B Number of MRs on Downlink TCHF (Receive Level Rank 6 and Receive Quality Rank 3)(times) S4163A Number of MRs on Uplink TCHF (Receive Level Rank 6 and Receive Quality Rank 3)(times)
S4164B Number of MRs on Downlink TCHF (Receive Level Rank 6 and Receive Quality Rank 4)(times) S4164A Number of MRs on Uplink TCHF (Receive Level Rank 6 and Receive Quality Rank 4)(times)
S4165B Number of MRs on Downlink TCHF (Receive Level Rank 6 and Receive Quality Rank 5)(times) S4165A Number of MRs on Uplink TCHF (Receive Level Rank 6 and Receive Quality Rank 5)(times)
S4166B Number of MRs on Downlink TCHF (Receive Level Rank 6 and Receive Quality Rank 6)(times) S4166A Number of MRs on Uplink TCHF (Receive Level Rank 6 and Receive Quality Rank 6)(times)
S4167B Number of MRs on Downlink TCHF (Receive Level Rank 6 and Receive Quality Rank 7)(times) S4167A Number of MRs on Uplink TCHF (Receive Level Rank 6 and Receive Quality Rank 7)(times)
S4170B Number of MRs on Downlink TCHF (Receive Level Rank 7 and Receive Quality Rank 0)(times) S4170A Number of MRs on Uplink TCHF (Receive Level Rank 7 and Receive Quality Rank 0)(times)
S4171B Number of MRs on Downlink TCHF (Receive Level Rank 7 and Receive Quality Rank 1)(times) S4171A Number of MRs on Uplink TCHF (Receive Level Rank 7 and Receive Quality Rank 1)(times)
S4172B Number of MRs on Downlink TCHF (Receive Level Rank 7 and Receive Quality Rank 2)(times) S4172A Number of MRs on Uplink TCHF (Receive Level Rank 7 and Receive Quality Rank 2)(times)
S4173B Number of MRs on Downlink TCHF (Receive Level Rank 7 and Receive Quality Rank 3)(times) S4173A Number of MRs on Uplink TCHF (Receive Level Rank 7 and Receive Quality Rank 3)(times)
S4174B Number of MRs on Downlink TCHF (Receive Level Rank 7 and Receive Quality Rank 4)(times) S4174A Number of MRs on Uplink TCHF (Receive Level Rank 7 and Receive Quality Rank 4)(times)
S4175B Number of MRs on Downlink TCHF (Receive Level Rank 7 and Receive Quality Rank 5)(times) S4175A Number of MRs on Uplink TCHF (Receive Level Rank 7 and Receive Quality Rank 5)(times)
S4176B Number of MRs on Downlink TCHF (Receive Level Rank 7 and Receive Quality Rank 6)(times) S4176A Number of MRs on Uplink TCHF (Receive Level Rank 7 and Receive Quality Rank 6)(times)
S4177B Number of MRs on Downlink TCHF (Receive Level Rank 7 and Receive Quality Rank 7)(times) S4177A Number of MRs on Uplink TCHF (Receive Level Rank 7 and Receive Quality Rank 7)(times)
As seen above, in that TRX there is some Uplink signal level problem. Cross connection, VSWR may be problem.
As a result, according to TA distribution, RLT over TA distribution and TCH Receive Level measurements;
If Iell’s TA distribution shows cell covers a big area with overshoots, coverage gap related call drop may occur.
If Iell’s RLT o┗er TA aミd TA distriHutioミ sho┘s together, Iell Io┗er a Hig area aミd drop gathers iミ oミe TA (or soマe of TA), coverage gap related call drop may occur.
If Iell’s TCH ReIei┗e Le┗el マeasureマeミts sho┘s Iells ha┗e uミHalaミIed upliミk aミd do┘ミliミk R┝Le┗els, it マeaミs Iell is a dragon cells with overshoot service areas or have HW problem.
For solutions of coverage gaps and overshoot problems, cells antenna direction, height, mechanic and electric tilt degree may
be changed or cell addition may be done. For HW problems, HW check should be done detailed.
3.3.4 QUALITY and INTERFERENCE PROBLEMS
For finding quality and interference problems;
さInterference Band Measurement per Cellざ,
さNeighbor Cell Level Measurement per Cellざ,
さTCHF ReIei┗e Le┗el Measureマeミt per TRXざ, さTCHH ReIei┗e Le┗el Measureマeミt per TRXざ マeasureマeミt sets should He used.
さIミterfereミIe Baミd Measureマeミt per Cellざ Iouミters are sho┘ミ Helo┘;
With these counters, BTS measure uplink interference according to below signal level table. If there is interference, it means
that Band5 counters should be incremented.
As seen above, generally this TRX has less interference
If Band5 numbers is high, it means cell have uplink interference and frequency change should be considered. (Keep in mind
that BB Hopping will affect this result, for test hopping should be closed)
COUNTER NUMBER COUNTER NAME
AS4200A Mean Number of SDCCHs in Interference Band 1(number)
AS4200B Mean Number of SDCCHs in Interference Band 2(number)
AS4200C Mean Number of SDCCHs in Interference Band 3(number)
AS4200D Mean Number of SDCCHs in Interference Band 4(number)
AS4200E Mean Number of SDCCHs in Interference Band 5(number)
AS4207A Mean Number of TCHFs in Interference Band 1(number)
AS4207B Mean Number of TCHFs in Interference Band 2(number)
AS4207C Mean Number of TCHFs in Interference Band 3(number)
AS4207D Mean Number of TCHFs in Interference Band 4(number)
AS4207E Mean Number of TCHFs in Interference Band 5(number)
AS4208A Mean Number of TCHHs in Interference Band 1(number)
AS4208B Mean Number of TCHHs in Interference Band 2(number)
AS4208C Mean Number of TCHHs in Interference Band 3(number)
AS4208D Mean Number of TCHHs in Interference Band 4(number)
AS4208E Mean Number of TCHHs in Interference Band 5(number)
Interference Band Level Threshold of the Interference Band
Interference band 1 -105 dBm to -98 dBm
Interference band 2 -98 dBm to -90 dBm
Interference band 3 -90 dBm to -87 dBm
Interference band 4 -87 dBm to -85 dBm
Interference band 5 -85 dBm to -47 dBm
INNER PARAMETER Name Value
Neighbour Cell Interference Level Threshold 0 0
Neighbour Cell Interference Level Threshold 1 49
Neighbour Cell Interference Level Threshold 2 55
Neighbour Cell Interference Level Threshold 3 61
Neighbour Cell Interference Level Threshold 4 64
Neighbour Cell Interference Level Threshold 5 67
Neighbour Cell Interference Level Threshold 6 73
Neighbour Cell Interference Level Threshold 7 79
さNeighHor Cell Le┗el Measureマeミt per Cellざ Iouミters are sho┘ミ Helo┘.
According to inner BSC parameter settings, these counters
incremented when measured Neighbor Cell signal level and serving
cell signal level difference greater than related threshold. These
thresholds are shown on the left.
As seen below, serving cell measures all BCCH in its active Ba List
and decodes BSIC (not needed to be neighbor, but BCCH frequency
should be in active Ba List). According to thresholds, co-channel and adjacent channel interferer of serving cells could be
found.
COUNTER NUMBER COUNTER NAME
S363Number of MRs in Which the Signal Strength Difference Between the Serving Cell and the
Neighbor Cell is Smaller Than the Neighbor Cell Interference Level Threshold 1(number)
S364Number of MRs in Which the Signal Strength Difference Between the Serving Cell and the
Neighbor Cell is Greater Than the Neighbor Cell Interference Level Threshold 1(number)
S365Number of MRs in Which the Signal Strength Difference Between the Serving Cell and the
Neighbor Cell is Greater Than the Neighbor Cell Interference Level Threshold 2(number)
S366Number of MRs in Which the Signal Strength Difference Between the Serving Cell and the
Neighbor Cell is Greater Than the Neighbor Cell Interference Level Threshold 3(number)
S367Number of MRs in Which the Signal Strength Difference Between the Serving Cell and the
Neighbor Cell is Greater Than the Neighbor Cell Interference Level Threshold 4(number)
S368Number of MRs in Which the Signal Strength Difference Between the Serving Cell and the
Neighbor Cell is Greater Than the Neighbor Cell Interference Level Threshold 5(number)
S369Number of MRs in Which the Signal Strength Difference Between the Serving Cell and the
Neighbor Cell is Greater Than the Neighbor Cell Interference Level Threshold 6(number)
S370Number of MRs in Which the Signal Strength Difference Between the Serving Cell and the
Neighbor Cell is Greater Than the Neighbor Cell Interference Level Threshold 7(number)
さTCHF ReIei┗e Le┗el Measureマeミt per TRXざ Iouミter マa┞ He used for deteItiミg iミterfereミIe proHleマ also. Qualit┞ proHleマs like high Rxquality may be caused by low signal level. But interference means quality is bad in good signal level also. As seen
below with these counters, quality in good and bad signal levels for uplink and downlink could be detected.
distribution. From the graphs, it could be said that, there is
an uplink signal level problem but no interference
problem.
As a result, if quality problems exist in a cell, with help of
above stats we should define is there an adjacent or
cochannel frequency or is it related with signal level.
If it is frequency, with help of neighbor cell level
measurement we could find the best frequency for cell.
If it is a signal level problem we should analysis for
coverage gap and HW problems.
3.3.5 MISSING NEIGHBOR PROBLEMS
Another cause of high drop rate is missing neighbor. Missing neighbor may be a real closer cell to serving cell or because of
serving cell overshoot there is a far away cell that should be neighbor.
Best way to find missing neighbor is analysis with help of さNeighHor Cell Le┗el Measureマeミt per Cellざ counters.
These counters collects all BCCH-BSIC reported by MS in MRs for serving cell. By thresholds in BSC Parameters, related
counter is incremented according to signal level difference between serving cell and measured BCCH-BSIC.
For finding missing ミeighHor, ┘e should IolleIt さNeighHor Cell Le┗el Measureマeミt per Cellざ for a period (keep iミ マiミd that active ba list of serving cell should be modified as contain all BCCHs). Than with help of MRs on TCHs counter, you could find
which BCCH-BSICs are measured above a certain threshold. Than in these measured BCCH-BSICs, which ones are defined as
neighbor which ones are not, you could find. (Keep in mind that same BCCH-BSIC in an area may affect reliability of result. So
try to give same BCCH-BSIC to cells that distance between them are as far as you can).
For example from analysis this cell should be defined as neighbor with serving cell.