- This topic has 5 replies, 1 voice, and was last updated 8 years, 3 months ago by pix.
18th October 2012 at 16:45 #68652SANEGuest
About interworking NSS HUAWEI and BSS ALCATEL, one MS was in LAC(1) CellID (A) with TMSI(1), and few seconds later move to LAC(2) CellID (B) with TMSI(2).
Unfortunately, the paging was sent to LAC(1) CellID (A) with TMSI(1) for a MT Call attempted after changing location.
Then, A-party received an announcement “MS is not reachable”.
Could you tell me the possible causes ?
If TMSI reallocation when MS moves from one LAC to another is a normal behavior ?
Best regards18th October 2012 at 18:57 #68653pixGuest
yes it is a usual operation during LAU.
to reduce those radio ping pongs between LAC, you could increase the Cell Reselect Hysteresis (CRH) up to 16dB on both cells.
Your scenario is quite extreme. The duration of a LAU is so short that it’s really bad luck if the MS is changing LAC while NSS is trying to page it. It’s really a matter of few seconds.
The only thing is to avoid ping pong LAU, for sure.
CRH is a good thing. Try also increase TO and PT (temp offset, penalty time), to values 4 (40dB) and 3 (40s) for example, that’s enough to avoid stupid reselections.
pix20th October 2012 at 05:27 #68654AghaGuest
Thanks for ur reply:
“The duration of a LAU is so short that it’s really bad luck if the MS is changing LAC while NSS is trying to page it”
If TMSI is reallocated so why paging on previous LAC?20th October 2012 at 11:13 #68655pixGuest
But when does this happen compared to the LAU : 1s after ? 5s after ? 10s after ? 30s after ? All the time ?
What’s for sure is that this behaviour comes from the MSC/VLR/HLR which is not properly up to date. Unfortunately, I know nothing about NSS 🙂
The TMSI realocation clearly indicates that the VLR has mapped this IMSI to the new LAC. But is the HLR aware of that yet ?
Just brainstorming 🙂
pix22nd October 2012 at 05:18 #68656AghaGuest
Agreed,thats why i call u pix ::
P— Person of
X— Xchanger…:)22nd October 2012 at 18:10 #68657pixGuest
plz share info if/when you have them !