Handover Success Rate (HOSR):

If HOSR will be good TCH drop will also be good.
If Handover success rate degrades call drop rate will take place.

Reasons for Poor HOSR:
Improper Neighbor planning.
CO-BCCH-BSIC issues in Neigh.
Parameter Check.
HSN clash.
SL value.
LAC boundary.
DAC value mismatch.
Syn mismatch.
Overshoot.
HW Issues.
Low Coverage

Solutions for removal of HOSR:

Arrange Drive Test:

The best way to find the real issues for HO fail make DT and check layer 3 msg for HO fail. By DT it is very easy to find the fail between cells.

Neighbor Tuning:

Try to retune neighbors
Avoid CO-BCCH-BSIC neighbors.
Avoid extra neighs.
Delete long distance neighs.
Check neighs are defined form both ends.
If there are high fail delete and recreate neighs.

Parameter Check:
1. Retune SL.It can change bw -90,-95,-105.
2. Check HSN.
3. Check SYN.
4. Retune LDR, LUR, IDR, IUR.
5. Retune LMRG, QMRG, PMRG.

DAC value Check:

Check DAC value. If DAC value is high or low tune it at the TH value. It should be 2050.

Overshoot:

When neighs are far away then chances of HO fail increases. In this case ping-pong HO takes place by which fail takes place. So if the inter distance is high its better to delete that kind of neighbour.

LAC Boundary-

Check LAC boundry.
High fail takes place there will be Inter BSC cells.
High fail takes place there will be Inter MSC cells.
Define proper LAC in neigh cells.

HW Issues:
Clear HW issues.
Check TRXs.
Check outages.
Check BOIA Card. Because if it is faulty incoming and outgoing HO will be fail.

Clear Reports:

Clear ZEAT.
Clear 60.
Clear 67.
Clear 61.

Reports for HOSR :
153 reports for HO fail bw two cells.
154 HO analyses.
60 for discrepancy.
67 for Sync report.
61 for one way neigh.
    ZEAT for CO-BCCH-BSIC neighs
74 for HO definition report.
ZELO for inter MSC HO report.
150 for high HO fail.
157 for high HO attempt and call ratio.
158 for intra BSS HO observation.
62 for Adj cell having same or adj freq.