Check if the cell is not overshooting and power per sector is not configured too high.
Check the CRSgain parameter if needed set to zero (default value)
2. Alarms*
Need to check alarm for HW fault and Transport alarm and Mixed Mode Configuration issue.
3. High UL RSSI Issue
High UL N+I is impacting to all KPIs. UL NI values {-119 …….. -110 dBm} is considered to be good.
The cause may be Internal Sources (Check Tx & Rx antenna ports, fiber cables and connectors. All connection should be proper) and External Sources ( like repeaters, airport, power plant etc. sources resulting in high EMW in the neighborhood).
pmRadiorecInterferencePwr is checked for UL N+I values.
4. VSWR over threshold*
The cabx command provides VSWR status for RL1 & RL2 (for 2T2R). Both, RL1 and RL2 should be difference of less than 5.
5. HO failure : If a sector is having high HO Execution fail, it results in poor retainability.
Probable Solutions: -
The counter pmErabRelAbnormalEnbActHo is checked. If this counter is pegging high, it implies poor retainability and resolution of sector HOSR is required.
6. Missing Neighbour
As we implement ANR in the network, just need to make sure that Eutranfreqlrelation to 1350 already created on the EnodeB (per Eutrancell)
Counter-wise problem identification Steps :
NOTE: MME drops are also very high during Poor RET. Need to investigate at MME end.
There is a limitation in MME drops analysis, these cannot be analyzed with the help of ENIQ alone, we need MME statistics for this.
If MME drop is high, we need to investigate through the following steps :
- If BH/Core issue >>> All sectors will be impacted
- If MME issue >>> Multiple sites in the NW will be impacted.
SARR - Issues & Solutions
1. pmErabRelAbnormalEnbActCdt – The total number of abnormal ERAB releases by the eNB per cell due cell down time (manual intervention) with the pre-condition that the Initial Context Establishment procedure must first have been successfully completed and that there was data in either the UL or DL buffer (i.e. active).
Probable Solutions : - Check Outage report or Fluctuation Report.
2. pmErabRelAbnormalEnbActHo – The total number of abnormal ERAB releases per cell by the eNB due to handover execution failure and that there was data in either the UL or DL buffer (i.e. active).
Probable Solutions:-
- Check PCI Planning is correct or not, to avoid PCI collision issue. There should not be any PCI re-use in nearby cells (Tier 1, Tier 2 neighbours).
- Coverage issue(make Any PCI Dominant which should be based on Clutter as per Common sense). Make EDT, Change Azimuth
- High UL Interference issue on Target cell (PmRadiorecInterferencePwr). Check Connection b/w Antenna Connector & RRU Connector.
- Also Repeater is responsible sometimes for Hi-UL Interference. Might be due to Power Leakage.
3. pmErabRelAbnormalEnbActUeLost – The total number of abnormal ERAB releases by the eNB per cell due that the contact with the UE is lost with the pre-condition that the Initial Context Establishment procedure must first have been successfully completed and that there was data in either the UL or DL buffer (i.e. active).
Probable Solutions:-
- Solve the Poor Coverage issue by changing tilt / azimuth or appropriate parameter value setting, E.g. : - partOfSectorPower, ENB Power, P0NominalPucch / P0NominalPusch (for uplink Coverage).
- High UL NI Issue(As per earlier mentioned. Also make sure Nominal power Should not set very high otherwise it will create interference in neighbour cell).
4. pmErabRelAbnormalEnbLic – The total number of abnormal E-RAB Releases initiated by the RBS due to license reject (per cell).
5. pmErabRelAbnormalEnbActTnFail – The total number of abnormal ERAB releases per cell due to S1 interface down, "X2 interface down" or "Transport Resource Unavailable", with the pre-condition that the Initial Context Establishment procedure must first have been successfully completed and that there was data in either the UL or DL buffer (i.e. active).
Probable Solutions : - Issue can be resolved with the help of NOC / IM Team by raising the required tickets.
6. pmErabRelAbnormalEnbActHpr – The total number of abnormal ERAB releases by the eNB per cell due to handover preparation and that there was data in either the UL or DL buffer (i.e. active).
Probable Solutions:-
- MME missing issue or MME might be disabled.
- Transport issue suspected.
- License issue suspected.
- Site Configuration issue.