- This topic has 26 replies, 1 voice, and was last updated 11 years, 2 months ago by pix.
19th September 2008 at 14:47 #47186pixGuest
well… i can’t really help, but you should double check the definition of your external cells within the iBSC’s OMCR. The BSC just follows OMC-R configuration. Have you put the correct BCCH and BSIC ? The correct LAC ? Correct CI ?
I forgot to tell you that during drivetest, you should also check whether the MS measures the RXLEV of these external neighbors or not. In the SI2 and SI5 (system info msg that contain the list neighbors BCCH), do you see the BCCH of the external cells ?
If the BCCH are not present in SI2 and SI5, then it means the external cells are not defined as neighbors in the OMCR.
You can read the SI2 & SI5 in TEMS investigation “layer 3” window.
If you feel everything is correctly defined, then ask for ZTE support.
They are here to support you, aren’t they? 🙂
Let me know how it goes.
Pix24th September 2008 at 11:43 #47187MaheshGuest
i want to know wht is the effect of Extra neighbour addition on HOSR..& WHY25th September 2008 at 13:03 #47188EugeGuest
I got a problem with HOs between some cells in a new ericsson BSC we recently intergrated.
All HO failures we get are due to PROTOCOL ERROR.
For some cells we cant even do cell reselection. the measurement reports C1 and C2 are invalid for neigbouring cells.
We have checked all C1 & C2 parameters are ok, Neihbour relations are defined together with MFs.
Please help as this has increased dropped calls & congestion on some cells.26th September 2008 at 02:43 #47189turdGuest
Hi Pix, I’ve also experience what euge had experience.Im using nokia metrosite site with 2TRx.When ever i camped to the BCCH of the metrosite, the cell selection/cell reselection C1/C2 of the neighboring cells are not present in our TEMS. Conversely,if i camped to any of the neighbor cells of the metrosite, the metrosite C1/C2 is now the one not present with all other neighbors’ C1/C2 present.
InterCell hand-over to other cells except to the BCCH of metrosite is OK.
Also in idle mode,if our Rx Lev is -55dBm,whenever we are engaged to call/dedicated mode,Rx level fluctuates/degrades to atmost 20dB.
Can you suggest what can we do? We already check the functionalities of the TRx’s.Cable VSWR is also acceptable.26th September 2008 at 08:01 #47190PixGuest
Sorry, I’m quite in a hurry:
Euge > if there is HO failures, it means the neighbors are well defined in the BSC but there is an issue within the BSC itself.
You confirm that the HO fails between 2 cells within the same BSC ?
During drivetests, the MS receives a HO CMD. Then the MS sends HO ACCESS to the target cell.
Could you analyze both messages in TEMS, what are the contents you see ? Do they match the actual description of the neighbor cell ?
If you can, try to perform some Abis interface on serving and target cell. If you see that the BTS sends a message to the BSC, and receives a response = HO FAILURE, then you can simply assume the BSC has a problem… so raise the issue to your ericsson support26th September 2008 at 08:04 #47191pixGuest
Turd > could you read the system information 5, 5bis (on BCCH, in idle mode) and 2, 2bis (on SACCH, in dedicated mode) in TEMS ? You can see them in layer 3 messages.
You should see the list of all neighbor BCCH that shall be measured by the MS.
If you see some BCCH are missing, you should double-check your adjacencies definition in OMC-R. If it was correct (good neighbours definition), then you must assume your BSC is going crazy (database corrupted).
If BCCH are well defined in the SI msg, then check the content of the MEASUREMENT REPORT. The 6 strongest BCCH shall be reported. Do you see the “BCCH index” of the metrosite for instance? At which RXLEV ?
I’m just giving you some leads, hopefully you’ll find something useful in there 🙂
Pix29th September 2008 at 00:30 #47192TurdGuest
Thanks for your reply.I’ll try to check when i go back to the site.The site is 5-hr trip away from from me.I’ll give you feedback on what will happened.29th September 2008 at 00:39 #47193TurdGuest
The BCCH of all the neighbors are present.Just the C1/C2 and the BSIC of the metrosite is present if i was camped on the BCCH,this time 837, the metrosite.Neighbors BCCH list are 9,17,110,5,20,109.If I camped to any of the neighbors a make a force hand-over to 837,no HO attempts has ever made.But if HO will be made to other BCCH except 837,attempts is OK.
Previous history of the site has made some modification on its parameters before this situation happens.I am planning to make delete/recreate on all its parameters.Maybe there are already discrepancies on the entries of the database,.
Regards,29th September 2008 at 06:11 #47194pixGuest
thx for the details. It’s not clear though 🙂
MS camps on a neighbor: Can you see 837 in the SI msg n°5 or n°5bis/ter ?
When camping on a BCCH, the MS shall receive a SI msg that contains GSM900 neighbors, and another SI msg that contains DCS1800 neighbors (SI5 & SI5 bis or ter, i forgot)
do you see those 2 different SI msg ?
Let me know what happens after you recreate the cell. Check also that you allow multiband operation (by allowing the transmission of the second set of neighbor list), this should be a radio parameter.
Pix8th October 2008 at 08:54 #47195eugeGuest
Thanks for the response.
Actually the problem was sorted out. The sites involved are multiband cells and had problems with synchronisation hence HO failures & no cell reselection.
Thank you very much for your reply.
eugene14th February 2010 at 08:09 #47196RamuGuest
When BSC sends the System Information 5bis to BTS.pto my knowledge when the BCCH neighboring cells doesn’t fit into SI5,then SI 5bis will be sent. I have done two cases(separately) for the same:
1.defined 26 neighboring cells
2.Defined 1023(which doesn’t fit in 0-123 bit map)
In both cases 5bis not sent by BSC and don’t know, when will BSC sends 5bis to BTS.
Can anybody tell when BSC sends 5bis to BTS ??14th February 2010 at 08:47 #47197pixGuest
5bis is sent for neighbours that belongs to another frequency band than the serving cell. (DCS1800 neighbours when serving is GSM900, for example)