In LTE after RLF UE need to carry out RACH process again for RRC connection re-establishment?
Yes it’s after t310 expiry and need to make sure it’s contention free happening.
If it sync in during t310 then no need for reestablishment.
Thanks. But contention free RACH process is during HO only and other than that it will be contention based RACH that is during rrc re-establishment during. Non HO scenario.
In Huawei there is switch for unsync ra which behaves as Contention free, this needs to be enabled.
Or else it works as contention based.
For initials access contention based is a must for remaining we have options.
After DRB sync out you can have contention free.
But not during SRB.
So in case of contention free RACH after DRB sync out UE uses dedicated preamble or preamble from groupA/B.
What is the name of the switch?
If this switch is enabled, how the preamble is allocated to the UE after RLF?
I mean in which message?
Unsync ra switch.
And ho ra switch.
In cell also switch command.
After Ho ra switch.
Both needs to be ON.
Ok. But how preamble is delivered to the UE after RLF?
eNodeB instruct UE contention-based / non-contention-based according to these parameters:
HoRaSwitch: indicates wheter the random access mode is applied during handovers.
UnsyncRaSwitch: indicates wheter the random access mode is applied when UEs are out of synchronization in the uplink.