2G to 3G reselection

[Mdaf]

Hello,
Do we have standard time for reselection from 2G to 3G, for example if IRAT took place from 3G to 2G during decidcated mode then after normal release UE will perfom LU on 2G then the Ue starts looking for neighbors (2G &3G) do we have any standard or average time so that the UE will be back to 3G (assuming excllent RF conditions).
could we say on average mobiles need 30 seconds, 1 minute......
please share if you have any experince in this issue.
many thanks

[faisaladeem]

Hi,
The best way to speed up 2G to 3G reselection after IRAT HO on 2G is to implement Fast return from 2G to 3G feature (for R7 on wards UEs, at call release, 3G cell with best measurement result is indicated for re-selection bypassing location update and normal re-selection process). If you don't have license for this feature, try keeping 2G to 3G neighbor list short (reducing SIB 2 quarter blocks that UE has to read in order to start re-selection to 3G).

[Mdaf]

Many thanks for the valuable info how to speed the reselection, my main concern was to know the average time to reselect again under normal circumstances.

[faisaladeem]

It can take anywhere between 10s to 60s depending upon the speed of UE, neighbor list and vendor specific SIB2quarter scheduling. In one of the network I saw it was taking ~27s to get 7 blocks of SIB2quarter and when neighbor list was even longer, it was going until 8 blocks of SIB2quarter!

[Mdaf]

Could you please explain what do you mean by vendor specific sib2 quarter

[faisaladeem]

The periodicity of the SIB2 quarter appearance (or any other SIBs) follows from vendor's scheduling. It varies from vendor to vendor.

[baby2]

one more need to concern

multi RAB ,with background PS service

as faisaladeem mention ,imp fast return is the fast way

from my experience ,it take time 5-10 second