Probable Reasons of Bad Handover Performance

---Neighboring Cell Relation
Action:Add neighbor cell relation.


---Missed measurement frequencies in BA-list
Action:Check measurement frequencies list.


---Permitted Network Color Code problem
Action:Check NCC Permitted


---HW faults.
Action: Check BTS error log.






---Blocking on Target Cell
Action:Remove Blocking on Tager Cell



---Congestion
A high congestion might lead to dragged calls (handover performed at a not intended location) and a lot of unsuccessful handovers.
Action: Check TCH congestion.


---Timer Expire After MS is Lost
The MS never answers the base station.
Action: Check coverage. Check interference.


---Link Connection or HW Failure
Action: Check BTS error log. Perform site visit. Perform link performance measurements.


---Bad Antenna Installation
Action: Perform site survey and check antenna installation. Check antenna cabling.


---Many Neighbors Defined
Many defined measurement frequencies defined (>16) will decrease the accuracy of the mobile measurements to locate the best six servers. Many measurement frequencies mean few samples per frequency and problem for mobiles to decode the BSIC.


Action: Check number of definitions.
---Delayed Handover Decision
A delayed handover decision can be due to congestion in the target cell.
Action: Check handover parameters.



---Wrong Locating Parameter Setting
Action: Check locating parameters.



---Bad Radio Coverage
Action: Check coverage plots.



---High Interference, Co-Channel or Adjacent
The potential handover candidate is disturbed by interference. Outgoing handover due to bad uplink quality may indicate interference from co-channel another MS. On the border, the quality may be rather bad and the signal strength low. Bad downlink quality may indicate interference from another co-channel base station.
Action: Check interference. Check if many handovers are performed due to downlink or uplink bad quality.



---Receiver Antenna Problem or RBS HW problems (in candidate cell)
Action: Check antenna installation. Check RBS HW and Error log of the target cell



---Poor Inter-MSC/BSC Handover Performance
For outer or external cell, wrong definitions in either MSC or BSC may be reason for the problem.
Action: Check inter-MSC/BSC handover performance.



---Incorrect Down Tilt
Action: Perform site survey and check antenna installation.
Solution: Correct antenna tilting.