- This topic has 14 replies, 1 voice, and was last updated 8 years, 7 months ago by mlc.
12th January 2009 at 15:38 #55335roamerGuest
Can any one know website show me the operators roaming operator let say O2 to show me the roamer.13th January 2009 at 14:32 #5533628th February 2012 at 23:52 #55337RexGuest
can anyone explain how is it possible that when MS is not far from BTS with the level of -70 dBm roams to another operator with no so strong signal. Is it radio issue or NSS issue? Any experience like that?29th February 2012 at 19:26 #55338pixGuest
if the ms is located in its home plmn, it has no reason to attach to another PLMN. The only scenario is if:
1/ the serving cell is not able to provide service to the MS (strong interfence in UL or in DL, cell is barred, low rxlev…)
2/ there is no other cell from this PLMN around.
In this case, I think the MS could detach from the current PLMN and attach to the other PLMN. However, it will periodically attempt to re-attach to its home plmn.
pix29th February 2012 at 19:50 #55339RexGuest
the problem is that the level is good, MS near the BTS, there is no interference. 7 km far from that point there’s foreign operators BTS with lower signal level than home signal level. It’s strange.
Rex1st March 2012 at 09:34 #55340pixGuest
yes, it is very strange.
Do you have the (tems?) log of this behaviour ?
if yes, then you should check some parameters of this distance cell:
Regarding MNC/MCC : are they correctly set ? or are they identical to your own PLMN’s values ?
Regarding BCCH : is this frequency the same as one of your neighbours?
You could tune the parameter NCC_permitted, in order to have only your own NCC allowed for that particular cell.
Another (far-fetched) theory : the distant PLMN is considered as a “home plmn” in your SIM card. If that’s the case, then you have a big problem, as this is a hardcoded setting (in the SIM) that cannot be modified remotely.
pix9th March 2012 at 18:47 #55341RexGuest
thanks for your answer and contribution, as always.
NCC_Permitted is disabled in all cells. After some tests made, we noticed that this phenomenon happens not with every SIM card. In few of them even if signal level was -60 or -65 dBm they roamed to the other operator (with sig level lower than -80 dBm). With the other SIM cards everything was OK, staying in homePLMN. Do you think is SIM issue?
Rex10th March 2012 at 12:19 #55342pixGuest
the tests you have done seem to indicate that it is indeed a SIM issue. The next step : read this SIM card through a SIM reader (I recall TEMS Investigation provide such functionality, doesn’t it ?)
you can read the PLMN settings of the SIM, I guess…
Both sets of SIM were inserted in the same mobile phone ? The question is whether the mobile phone could be the problem here.
pix11th March 2012 at 03:44 #55343paraHOGuest
(a) it is SIM Card issue
(b) the roaming neighbour not required
(c) is it possible for you to add roaming neighbour to FPLMN (forbidden list)
paraHO13th March 2012 at 13:24 #55344RexGuest
Thanks Pix, paraHO
Pix, I think that’s not the phone issue because we tested many SIM cards in the same phone and the problems appeared only to those SIMs which previously roamed with very good conditions in home PLMN. I tried to check PLMN settings in SIM card with SIM reader (chinese SIMMAX) but there is nothing in application for managing PLMNs. Maybe I should try with Dekart Simreader.
I’ve read somewere here in forum about creating external cell. What do you think to create the foreign cell as external. In PRC there is not possible to change the parameter “PLMN name”, it’s always “own PLMN”. Any suggestion regarding external cell?
And another question regarding NCC_permitted. In our network NCC is 0 and NCC_permitted is not_permitted (value 0). Is that OK. Should we tune that?
And the last one, home MNC is 01 and foreigner operator’s MNC is the same 01. What’s the role of MNC in these situations?
Rex13th March 2012 at 18:55 #55345pixGuest
thata’s a good idea to create an external cell, use the same BCCH BSIC than the foreign cell, and apply strong penalty to avoid reselection to those cells. Really interesting idea.
The NCC PERMITTED should allow the NCC=0 to be reselected. Normally, every cell in your network should have NCC=0 allowed.
I think that MNC mobile network code is part of the PLMN id (= NCC + MNC) ? But I’m not sure about this, it has been a long time since I looked at such parameters 🙂
Regarding the PRC : first, i think you need to define another PLMN in the OMCR. Then you should be able to create an external cell that belong to another PLMN. Creating other PLMN might be an optional feature in the OMCR, I will check it out tomorrow at the office.
Let me know how the NCC PERMITTED setting will affect your situation. Tomorrow I will tell you what it is exactly doing.
(I now have so many things to do tomorrow !)
pix13th March 2012 at 19:11 #55346RexGuest
I haven’t any document regarding NCC_Permitted to read more about that. In OMCR there are eight values of ncc_permitted: 0 to 7. In our case there is 0. When we look in logical parameters in NPO it shows ncc_permitted=not permitted. I don’t know is it the right value. Network color code is 0. If we choose, let’s say, the value 7 (most significant bits), is that mean that we permit ncc=0 or we permit another plmn which has ncc=7. It’s a bit ambiguous to me.
Rex15th March 2012 at 12:40 #55347RexGuest
day before yeaterday I saw an answer related to my previous post, now it’s not here. Is it deleted for any purpose?
Rex15th March 2012 at 13:03 #55348pixGuest
yes, my post was deleted …????
what’s going on ?11th July 2012 at 15:13 #55349mlcGuest
Did you face before to this problem:
We are implementing a Full MVNO. The problem is that when the user put his phone to avoid data roaming he took the network of our MNO as roaming and the user cant connect to internet.
The question is if we need to configure the MSC/SGSN to send a equivalent list during the LU or we need to put that list in the SIM cards User Controlled PLMN Selector with Access Technology field??
Plase send your comments..