- This topic has 5 replies, 1 voice, and was last updated 12 years, 1 month ago by Pix.
20th March 2009 at 12:57 #56327RexGuest
What’s the purpose of timers:
1. WI_CR (Wait Indication for Establishment Cause=Call Re-establishment)
2. WI_EC (Wait Indication for Establishment Cause=Emergency Call)
3. WI_OC (Wait Indication for Establishment Cause=Originating Call)
4. WI_OP (Wait Indication for Establishment Cause=Location updating or Other procedures)
How important are these values?
Which are default values?
Can call setup delay reduced if WI_OC decreases?20th March 2009 at 13:56 #56328pixGuest
they are useful only if the feature IMMEDIATE ASSIGNMENT REJECT is activated.
those are important timers, they force the MS to retry a CH REQUEST on W_xxx later, instead of almost immediately.
Those timers are used only when the cell suffer SDCCH blocking. So they don’t improve the “delay” of Call setup, but they allow it in the first place !
If you reduce these timers, you reduce the chance of successful CSSR, and you increase the sDCCH Congestion.
Regards.20th March 2009 at 15:29 #56329RexGuest
Is it good to activate IMMEDIATE ASSIGNMENT REJECT? Will improve sdcch assignment failure? What’s the drawback of it?
Regards.20th March 2009 at 21:54 #56330PixGuest
No drawback, as far as i know. I always activate it.
It should/will reduce SDCCH Congestion.
don’t forget that there is no SDCCH Queue, so this is the only mechanism that help spread the resource requests and improve chances of success.
regards (and good night !)24th March 2009 at 19:45 #56331RexGuest
I activated IMM_ASS_REJ on one BSC which has more sdcch_cong, and I have to wait couple of days to see the effect, although I noticed a bit increase of LU rate in one cell (probably that’s not because of IMM_ASS_REJ). What about parameter RE (call re-establishment), it is disabled for all cells. Is that parameter related to WI_CR or not? Should I activate it?
Rex24th March 2009 at 20:28 #56332PixGuest
If call reestabilshment (CR) is activated, then a MS doing a CR will be forced to wait WI_CR between two consecutive RACH.
So that’s simple.
Now, i’m going to add something that doesn’t change what i said above 🙂 I’m not sure what is the purpose of the CR. I’ve never seen any MS that is reestablishing a call after a call drop.
Perhaps someone can enlighten me…?