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................................................................................. Maximum Value.

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Presentation on theme: "................................................................................. Maximum Value."— Presentation transcript:

1 ................................................................................. Maximum Value

2 ............................................................................... Maximum Value 1.HO Failures  C0-BCCH Interference on Target Cell.  C0-BCCH Interference on Serving Cell.  DL Interference on serving cell / UL Interference on Target cell.  Data Link Failures.  Bad radio Conditions. 2.Dropped calls  Delayed HO Command  Bad Quality.  HO Failure  Bad Quality. 3.Blocked calls  NO Immediate Assignment.  NO TCH Assignment 4.Missing Neighbors 5.Data link failures

3 ................................................................................. Maximum Value Analysis summary

4 ............................................................................... Maximum Value  HO Failures :- Problem ( 1 ) CO-BCCH Interference On  HO Failure Description. Serving Cell 12592 (CI: 12592, BCCH/BSIC: 79/7-0).. Target Cell 12593 (CI: 12593, BCCH/BSIC: 67/0-7).. HO Failure occurred due to target cell suffering from C0-BCCH Interference on BCCH: 67 from cell 6403 (CI: 6403, BCCH/BSIC: 67/7-1). Recommendation Check Frequency Plane.

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6 Problem ( 2 ) CO-BCCH Interference On  HO Failure Description. Serving cell C12964 (CI: 12968, BCCH/BSIC: 722/5-0).. Target cell C12963 (CI: 12967, BCCH/BSIC: 724/2-3).. HO failure occurred due to serving cell C12964 (CI: 12968, BCCH/BSIC: 722/5-0) suffers from CO-BCCH interference on BCCH: 722 from cell C12293 (CI: 12267, BCCH/BSIC: 722/1-5).. HO command was not sufficient because there was cell 1823 (CI: 1823, BCCH/BSIC: 67/5-0) appeared with better Rx_Lev but no HO command sent, cell may be congested. Recommendation. Check FP.. Check congestion on cell 1823.

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8 Problem ( 3 ) HO Failure Description. Serving Cell C06063 (CI: 6067, BCCH/BSIC: 718/1-7). Target Cell 5901 (CI: 5901, BCCH/BSIC: 71/1-0). HO Failures occurred due to target cell didn’t send, may be due to DL decoding problem because of bad FER as figure shows or due to target cell didn’t send physical information because of UL interference. Recommendation. Check DL interference on serving cell.. Check UL interference on target cell.. Open trace for HO success rate on target cell to check main reasons for HO Failures.

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10 Problem ( 4 ) Data Link Failure  HO Failure. Description. Serving Cell 1253 (CI: 1253, BCCH/BSIC: 67/3-5).. HO Failure occurred due to Data Link Failure. Recommendation Not RF problem.

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12 Problem ( 5 ) Bad Radio Conditions  HO Failure. Description. Serving Cell 19101 (CI: 19101, BCCH/BSIC: 79/5-5).. Target Cell 15601 (CI: 15601, BCCH/BSIC: 72/1-5).. HO Failure occurred due to bad radio conditions on serving cell. Recommendation Check alarms on cell 19101.

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14 Problem ( 6 ) Adjacent Channel Interference  HO Failure. Description. Serving Cell 3393 (CI: 3393, BCCH/BSIC: 80/6-6).. Target Cell 12204 (CI: 12204, BCCH/BSIC: 66/4-1).. HO failure occurred due to target cell 12204 (CI: 12204, BCCH/BSIC: 66/4- 1) suffers from adjacent channel interference on BCCH: 66 from BCCH: 65 of cell 7771 (CI: 7771, BCCH/BSIC: 65/1-7).. HO command was a wrong one because target cell was not better than the serving cell, although there is cell 7771 (CI: 7771, BCCH/BSIC: 65/1-7) appeared with better Rx_Lev no HO command sent cell may be congested. Recommendation. Check HO parameters.. Check FP.. Check Congestion on cell 7771.

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16  Dropped Calls :- Problem ( 1 ) Delayed HO  Bad Quality  Dropped Call Description. Dropped call occurred on cell 1541 (CI: 1541, BCCH/BSIC: 66/1-5) due to delayed HO which leads to very bad radio condition, although cell K31281 (CI: 1969, BCCH/BSIC: 67/2-5) appeared with a better Rx_Lev, No HO command has been sent, cell may be congested. Recommendation. Check outgoing HO parameter of serving cell.. Check congestion and HO parameter of cell K31281.

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18 Problem ( 2 ) HO Failure  Bad Quality  Dropped call Description. Serving cell: 7751 (CI: 7751, BCCH/BSIC: 66/5-5).. Target cell: K31284 (CI: 1978, BCCH/BSIC: 72/3-7)..HO failure occurred due to:  Co channel interference on BCCH: 72 of target cell from BCCH: 72 of cell 6543 (CI: 6543, BCCH/BSIC: 72/0-6).  Adjacent channel interference on BCCH: 66 of serving cell from BCCH: 65 of cell 7713 (CI: 7713, BCCH/BSIC: 65/1-1).. Dropped call occurred due to bad quality of serving cell. Cell 7714 (CI: 7714, BCCH/BSIC: 81/5-6) was nearer to the MS, but it appeared with a very bad Rx_Lev. This cell suspected to be down. Recommendation. Check FP.. Check alarms on cell 7714.

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20  Blocked Calls :- Problem ( 1 ) No Immediate Assignment  Blocked call Description. A Blocked call occurred while Cell 1513 (CI: 1513, BCCH/BSIC: 77/4-4) due to No Immediate assignment. Recommendation Check SDCCH Congestion on serving cell. Check Dynamic SDCCH allocation availability.

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22 Problem ( 2 ) No TCH Assignment  Blocked call Description. A Blocked call occurred while Cell 13471 (CI: 13471, BCCH/BSIC: 121/4-3) due to No TCH Assignment. Recommendation Check TCH Congestion on serving cell. Check Half Rate Availability to overcome congestion.

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24  Missing Neighbors :- Problem Missing Neighbors  Coverage Gap  Dropped call Description. Dropped call occurred on cell 12203 (CI: 12203, BCCH/BSIC: 64/5-5) due to very bad radio condition.. Cell K25861 (CI: 395, BCCH/BSIC: 83/5-2) and cell C06093 (CI: 6097, BCCH/BSIC: 728/4-7) supposed to serve in this area, but they are Missing neighbors.. Cell 41142 (CI: 41142, BCCH/BSIC: 79/0-2) appeared with a better Rx_Lev, but No HO command sent, cell may be congested. Recommendation. Add cells K25861 & C06093 to neighbor list of serving cell.. Check congestion and HO parameter of cell 41142.

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27  Data Link Failures :- Problem Data Link Failure  HO Failure. Description. Serving Cell 1253 (CI: 1253, BCCH/BSIC: 67/3-5).. HO Failure occurred due to Data Link Failure. Recommendation Not RF problem. Check SAPM Timer adjustments.

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29 1.HO from UTRAN Failure  Bad radio conditions on 2G target cell.  Bad radio conditions on 3G serving cell. 2.Pilot pollution 3.Dropped Calls  Missing Neighbor  Bad Quality  Dropped Call.  DL Bad Quality / RL congestion  Bad Quality  Dropped call. 4.Blocked calls  RRC Connection Abnormal release.  NO Radio Bearer Setup. 5.Missing Neighbors 6.Coverage Misbehavior  Fast 2d Event triggering  Unnecessary HO from UTRAN.  Fast 2d Event triggering  Ping Pong compressed Mode entering.

30 ................................................................................. Maximum Value Analysis Summary

31 ............................................................................... Maximum Value  HO From UTRAN Failure :- Problem ( 1 ) HO from UTRAN Failure Description. Serving cell: 15211 with SC: 152.. Target cell: C02101 (CI: 2105, BCCH/BSIC: 719/0-4).. HO from UTRAN failure occurred due to bad radio condition on target cell.. HO from UTRAN command was wrong where there is a Neighbor 16143 with SC: 174 appeared with a better radio condition, but no active set update occurred, cell may be congested.. UE send event to replace cell 16143 with cell 16923 with SC: 175 and this command was not sufficient where cell 16143 appeared with better condition than cell 16923. Recommendation Check active set update parameter. Check RL Congestion on cell 16143 / SC: 174.

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33  Pilot pollution :- Problem Pilot Pollution  Unnecessary HO from UTRAN Description. Cell 12992 with SC: 358 suffer from pilot pollution within this area which leads to bad EcNo coverage occurring event triggering. Recommendation Try to make dominant server at this area by  Down tilting some sites.  Increasing power for one of the cells to be dominant.

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35  Dropped calls :- Problem ( 1 ) Missing Neighbor  Bad Coverage  Dropped call Description.A dropped call occurred while cell 19282 SC: 474 serving with bad Radio condition due to there is a missing Neighbor 15332 SC: 83 which leads to coverage Misbehavior. Recommendation Add cell 15332 to the neighbor list of cell 19282.

36 ............................................................................... Maximum Value Problem ( 2 ) DL Bad Quality / RL Congestion  Dropped Call Description. A Dropped call occurred while Cell 19653 with SC:139 serving due to delayed AS update may be coz of  DL bad quality which leads to RNC response can’t be decoded by UE.  There is RL congestion on the Neighbor 19913 with SC:218 Recommendation.Try to make a dominant server at this area to overcome pilot pollution.. Check RL congestion on cell 19913.

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38 Problem ( 1 ) RRC Connection Abnormal release  Blocked call Description. A Blocked call occurred while Cell: 17132 / CI: 54223 / SC: 94 serving with bad radio condition due to RRC Connection Abnormal release.. Although there is MN appeared with better conditions, No AS Update occurred, cells may be suffering from RL congestion Recommendation Not RF problem. Check RL Congestion on MN Neighbors.  Blocked calls :-

39 ............................................................................... Maximum Value Problem ( 2 ) No Radio Bearer Setup  Blocked call Description. A blocked call occurred while cell 53728 / CI:15301 / SC: 3 due to No RB setup complete, cell may suffering from DL interference that’s why RB setup message can’t be decoded. Recommendation Try to make dominant server at this area to over come bad coverage in order to make DL Interference limitations.

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41  Missing Neighbors :- Problem Missing Neighbor  HO from UTRAN Description.Cell 19463 / SC: 369 is A missing Neighbor to cell 17591 / SC: 366 which leads to HO from UTRAN regarding bad EcNo. Recommendation. Add cell 19463 to the neighbor list of cell 17591.

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43  Coverage Misbehavior:- Problem ( 1 ) Fast 2d Event Triggering  Unnecessary HO from UTRAN Description. There is early event threshold triggering which leads to unwanted HO from UTRAN & lost 3G coverage. Recommendation. Check 2d event triggering regarding.

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45 Problem ( 2 ) Fast 2d Event Triggering  Ping pong Compressed mode entering Description.Fast 2d event triggering which leads to ping pong compressed mode entering which leads to high RNC processing load & increases UL Interference. Recommendation. Adjust usedFreqThreshold to overcome unwanted compressed mode entering.

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47 1.No HS-DCCH Assignment  C0-BCCH Interference on Target Cell.  C0-BCCH Interference on Serving Cell. 2.Low CQI  Delayed HO Command  Bad Quality.  HO Failure  Bad Quality. 3.High DTX % 4.High NACK %

48 ................................................................................. Maximum Value Analysis Summary

49 ............................................................................... Maximum Value  No HS-DCCH Assignment:- Problem HS-PSDCCH Not Available Description. If the HS-PSDSCH is not available the UE will be assigned (resource dependent) a R99 DCH bearer. This will result in lower than expected throughput as R99 DCH bearers have a maximum bearer rate of 384kbps. Recommendation.Confirm parameter set is aligned to CIQ and HSDPA is enabled in the cell..Check for abnormally high load (UL and DL) using RNC counters over a low traffic period..Fault related loading may result in the allocation of a non-HSDPA bearer, If high load is present with low traffic, this indicates a problem with the Node B or antenna system, escalate to field operations to investigate further.

50 ............................................................................... Maximum Value  LOW CQI:- Problem Low CQI Observed Description. CQI – Channel Quality Indicator – is a measure of channel quality, estimated and reported by the UE and possibly adjusted by the NodeB before being used with lookup tables to determine the appropriate TFRC to use in the next scheduled TTI. As the NodeB does may not directly use the reported CQI values, discrepancy between the allocated TFRC and expected TFRC is possible..Low CQI results in a TFRC with low user data throughput and a high CQI results in high throughput within the capability of the UE and network. Recommendation. low CQI indicates poor channel quality, resulting from low RSCP and or Ec/No. Optimize the downlink coverage in the area of concern to improve coverage and or dominance.

51 ............................................................................... Maximum Value  High DTX %:- Problem Missing Neighbor  HO from UTRAN Description. DTX – The DTX percentage is a measure of the percentage of available TTI’s a given UE has not been scheduled for, that is, a high value near to 100% indicates that the UE is rarely being scheduled, a value close to 0% indicates that the UE is nearly always being scheduled. The following are possible causes of high DTX: a. UE is incapable of receiving subsequent TTI’s as defined by UE class. b. UE is being starved (under-scheduled) by an unfair scheduler. c. Lack of data to transmit, ie. The Node B’s buffer for the given UE is empty at or for a number scheduling intervals. i. Congestion on the Iub preventing the NodeB buffer from being replenished. ii. Slow or congested application server. d. UE does not receive scheduling indications on the HS-SCCH due to poor downlink coverage/interference. e. Level of sharing on the HS-PDSCH – ie. Number of users. If there are two active HSDPA users in a cells coverage area, DTX will approximate 50% per user (assuming round robin scheduling) and throughput will be halved. Recommendation. Where a consistently high DTX rate is observed in good RF across a wide area of a cells footprint it is probable that there is a hardware issue at the NodeB, this should be escalated to field operations to investigate further on site. It may be necessary to re-commission HSDPA on the site.. Where high DTX is observed sporadically throughout a session it is probable that there is insufficient data in the buffers for the UE to be continuously scheduled, this can be due to congestion in the Iub or an under-performing FTP server. Verify the performance of the FTP server with static testing and check RNC counters for Iub congestion events.

52 ............................................................................... Maximum Value  HIGH NACK %:- Problem High NACK % Observed Description. ACK vs. NACK – For every TTI in which a UE is scheduled to receive data, the UE will respond by sending an ACK or NACK depending on whether or not the transmission was correctly received or not.. As each NACK requires a physical layer retransmission of the transport block a high percentage of NACK’s can cause low throughput.. A consistently high NACK % indicates that the link adaptation algorithm is not able to adequately track the radio environment, this can result from: a. NodeB or ATS problem – when a site or cell is consistently showing high NACK % for all sessions on the site / cell, this can indicate a problem with the NodeB configuration or antenna system. b. UE is over reporting CQI – less likely scenario as CQI reporting accuracy is standardized. There is still a possibility that a UE under performs in this area however and this will cause a reduction in system throughput when more than one user is active in a cell. Recommendation. If the problem is observed on all HSDPA connections in a particular cell escalate to a field technician to verify the antenna system and antenna system settings in the NodeB for the affected cell/cells, and to confirm the HSDPA commissioning parameters, these should align to the CIQ data.. To overcome UE CQI over reporting it is possible to use the This activates the NodeB CQI adjustment algorithm which targets a NACK% of 10%. Warning – this can result is reduced user throughput in good RF. This parameter should not be changed without prior approval, if high NACK % observed :-  BER < 10 %  CQI is real so increase CQI  BER > 10 %  CQI Not Real so Decrease CQI

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