Call drop caused by access and handoff collision

Typical case:
MS origination call may be failed in poor coverage area in DT test, or call drop will happen very soon after successful origination. MS Rx level and pilot Ec/Io are all low, and MS Tx power is very high. As MS moves, MS Rx power will become larger and larger, but pilot Ec/Io is too bad to satisfy the demodulation requirement;
MS initializes again after call drop and stays in one new strong pilot; If MS originates successfully in good coverage area and passes the same DT rote, call drop will not happen;

Analyzing:
If system can not support access handoff (access handoff also need MS to support), then during MS access procedure, MS can only start handoff after finish access. The above case is belonging to call drop caused by access and handoff collision. If one MS starts origination in the edge of coverage area, because this is near to another cell, it is possible to meet handoff. But our system does not support access handoff, access and handoff will have collision and access has priority in system. Because access need some time, so MS Rx power will become higher and higher, but pilot Ec/Io will become lower and lower. At this time, the objective handoff pilot is becoming strong interference, when current pilot Ec/Io is lower enough; the forward link will become very bad and can not be demodulated successfully. The access will be failed. After access failure, MS will stay in new pilot (It is the objective handoff pilot). If MS originates successfully in good coverage area and passes the same DT rote, call drop will not happen, because at this time MS can carry the normal handoff procedure.

Note:
Access handoff can be supported after 5.4 version;
For terminals, 1X handset can support, but 95 handset can not.

Optimization method:
If system and terminals can support access handoff, this kind of problem will not happen;
Adjust network structure and soft handoff area. Extend soft handoff area in the area where the above problems are heavy, then MS will firstly handoff to another cell before access and MS will have enough time to finish access.