E******* Directed Retry

[boo3000boo]

Attached a small presentation about the feature Directed Retry.


Directed Retry to GSM attempts to off-load traffic from the WCDMA RAN to a co-sited GSM RAN. Speech call that has no ongoing packet connection is the only service that is targeted since it is also the only one that is safe to divert to GSM. The decision is triggered by a RAB Assignment Request from the core network. This message contains the information needed to identify the call as a speech-only call. Incoming calls are screened for suitable candidates according to the following criteria.
The call is a speech-only call with no ongoing packet connection.
The UE can be handed over to GSM.
If a call is chosen for Directed Retry to GSM, the request for the speech RAB will be rejected with cause “Directed retry” and then a request is made to the core network to relocate the UE to a specific GSM cell, using the Inter-RAT handover procedure


Hope its useful.

[mojash]

When there is a co-existing GSM RAN, excess traffic in a WCDMA cell may be offloaded to GSM If a call is chosen for Directed Retry to GSM, the request for the speech RAB will be rejected with cause "Directed retry" and then a request is made to the core network to relocate the UE to a specific GSM cell, using the Inter-RAT handover procedure. This handover is a blind one since the target cell is chosen not based on UE measurements.

Direct Retry is not best solution. E******* feature Load Handover to GSM is much better.

[babak1349]

Hello Mojesh,
You are right But there is a point here:
1) directed Retry to GSM is during RAB assignment procedure, it means there is NO CS RAB assigned and Radio Link setup for speech So it is actually is for RRC in WCDMA to TCH assignment in GSM
2) in Load based HO to GSM, the CS RAB already established and then the MS will be handed over to GSM(in this case you may have still high load)

Based on my experiences Directed Retry to GSM is not bad feature Even though the load is based on Used power in Cell only


Cheers