6 Replies Latest reply: Mar 5, 2012 1:43 AM by Stefano Costa RSS

GPRS lock on TC65 and TC65i

Newbie

Hi,
   Has anyone come across a problem with the Seimens TC65 and 65i concerning a GPRS lock following radio network instablility?

 

We have  devices with these boards running SMS only with no problems, but we also have many which run a GPRS report once a day and upto 0.1% of these a day are locking, unable to communicate and providing old (unchanging) Creg and GsmLvl information. We have had case wher the log is showing Creg = 5, GsmLvl = 26 but the is not registered in the VLR and is purged from the HLR after 24hrs of non- activity.
Even when Creg = 0, there is no apparent attempt by the board to register in the network.

 

We finally reproduced the problem and Cinterion suggest we add an airplane mode on/off when closing GPRS sessions. This sounds like a work-around to a known problem so I was wondering if anyone else has had such a problem or know of a decent fix?

 

Regards

  • Re: GPRS lock on TC65 and TC65i
    Newbie

    Hi Rosbif,

        I haven't understood the problem clearly. Can you please elaborate on the following points?

    1. When you close the GPRS session, sometimes you loose GSM connectivity as well?

    2. You have CREG retruning 5 in good coverage (26 RSSI) but actually GSM is not registered. How did you validate that?

    3. When you say, closing the closing the GPRS session, what AT commands or sequence you use?

    4. Who purges the SIM after 24 hrs of inactivity? Is it network operator?

    5. What you mean by 'network instability'? Do you mean to say that GSM is allowed, but GPRS registration is denied? If so, how do you determine that?

     

     

     

    Regards,

    Rakesh

    • Re: GPRS lock on TC65 and TC65i
      Newbie

      Hi Rakesh,
        Thanks for taking an interest in this. I'll try to explain it as I understand it. I'm not in development but support.

       

      We have several examples with the same synptoms but slightly different outcomes.

      We noticed devices not communicating yet there was no reason (Creg=5 GsmLvl good etc ...) But the CREG is not in line with the network view and the GsmLvl never changes even if the device is taken underground, so we are assuming this is old information, not updated.

      We validate the GSM registration with the HLR data from the SIM supplier.

      It is the SIM supplier that purges the registration information if no activity or registration received in 24hrs.

      We did notice that other devices were registering on 3 different local networks which suggests that the preferred operator does not have a strong signal at this location.

      This lead us to work on the idea that the "lock" occurs when there are network fluctuations.

      We have over 10, 000 devices working but around 0.1% a day lock up. We can get them working again if the GSM board is reset but this is not a practical solution in a eurpoean wide business.

       

      When we try and reproduce the problem we simulated the netowrk fluctuations by introducing a jamming signal very quickly. The GSM signal was lost, but it never recovered and logs just show Creg=0, GsmLvl = 0 with no attempt to reaatch or any sign that the real network level is being read.

      Although it is not showing a GsmLvl, the GSM coverage is good and there is no change to this state so we assume there is no attempt to read or register on the network.

       

       

      Here is an extract of the test log showing the end of the GPRS session and the loss of GSM. From the end of this extract the Creg remaind = 0 and the GsmLvl remaind = 0 despite all other devices reading a good signal and working normally.

       

      17/08/10 04:24:00.100  [WARN ] SCD10Appli BEARER CONNECTING
      17/08/10 04:24:04.693  [INFO ] SCD10Appli ----10s----
      17/08/10 04:24:05.022  [INFO ] SCD10Appli MBat=20494 mv
      17/08/10 04:24:05.022  [INFO ] SCD10Appli Perf EvPending=0/350
      17/08/10 04:24:05.037  [INFO ] SCD10Appli ----1MN----
      17/08/10 04:24:06.803  [INFO ] SCD10Appli GprsLockCheck (0/5
      17/08/10 04:24:06.803  [INFO ] SCD10Appli ----STATUS----
      17/08/10 04:24:06.818  [INFO ] SCD10Appli Mode:2
      17/08/10 04:24:06.818  [INFO ] SCD10Appli FIFO Disp:1 Sms:0 Trip: 0 Syst: 0
      17/08/10 04:24:06.834  [INFO ] SCD10Appli GpsOn:false ID:0 Nav:090710080634:+43.62641:+007.05020:003:019:+00185:331A7C:u:03
      17/08/10 04:24:06.834  [INFO ] SCD10Appli KON:false
      17/08/10 04:24:06.834  [INFO ] SCD10Appli Diag:true
      17/08/10 04:24:06.850  [INFO ] SCD10Appli Creg=5
      17/08/10 04:24:06.865  [INFO ] SCD10Appli GsmLvl=26
      17/08/10 04:24:06.881  [INFO ] SCD10Appli CpinReady =true
      17/08/10 04:24:06.897  [INFO ] SCD10Appli Cfun=1
      17/08/10 04:24:06.897  [INFO ] SCD10Appli SmsSim=0
      17/08/10 04:24:07.006  [INFO ] SCD10Appli 000100:0002FF:0004FF:000800:001003:002001:004000:008000:010001:020000:040000:080001:100002:2000FF
      17/08/10 04:24:07.022  [INFO ] SCD10Appli ATime=1442 mn
      17/08/10 04:24:07.022  [INFO ] SCD10Appli ADist=4700 m
      17/08/10 04:24:07.037  [INFO ] SCD10Appli IATime=86665952 ms
      17/08/10 04:24:07.037  [INFO ] SCD10Appli IADist=4768 m
      17/08/10 04:24:07.053  [INFO ] SCD10Appli MBat=20480 mv
      17/08/10 04:24:07.053  [INFO ] SCD10Appli BBat= 4074 mv
      17/08/10 04:24:07.053  [INFO ] SCD10Appli GprsLocks=0
      17/08/10 04:24:07.397  [INFO ] SCD10Appli Threads= 15 MemTotal=589824 MemFree=100960
      17/08/10 04:24:14.615  [INFO ] SCD10Appli ----10s----
      17/08/10 04:24:15.162  [INFO ] SCD10Appli MBat=20494 mv
      17/08/10 04:24:15.162  [INFO ] SCD10Appli Perf EvPending=0/350
      17/08/10 04:24:21.740  [WARN ] SCD10Appli BEARER IS UP
      17/08/10 04:24:24.693  [INFO ] SCD10Appli ----10s----
      17/08/10 04:24:25.490  [INFO ] SCD10Appli MBat=20460 mv
      17/08/10 04:24:25.600  [INFO ] SCD10Appli Perf EvPending=0/350
      17/08/10 04:24:25.928  [INFO ] NetworkUtils httpRequest() finished, requestID= 255 ServerReply= 0
      17/08/10 04:24:25.943  [INFO ] Network gprsRequest() OK
      17/08/10 04:24:31.740  [INFO ] SCD10Appli #URC:+CIEV: lsta,0,4,49
      17/08/10 04:24:32.756  [INFO ] SCD10Appli #URC:+CIEV: lsta,0,3,0
      17/08/10 04:24:33.865  [INFO ] SCD10Appli #URC:+CIEV: lsta,0,2,0
      17/08/10 04:24:34.756  [INFO ] SCD10Appli ----10s----
      17/08/10 04:24:35.006  [INFO ] SCD10Appli #URC:+CIEV: lsta,0,1,0
      17/08/10 04:24:35.334  [INFO ] SCD10Appli MBat=20494 mv
      17/08/10 04:24:35.334  [INFO ] SCD10Appli Perf EvPending=0/350
      17/08/10 04:24:36.115  [INFO ] SCD10Appli #URC:+CIEV: lsta,0,0,0
      17/08/10 04:24:39.834  [INFO ] SCD10Appli #URC:+CIEV: lsta,1,26,1,52,26,150
      17/08/10 04:24:44.756  [INFO ] SCD10Appli ----10s----
      17/08/10 04:24:45.459  [INFO ] SCD10Appli MBat=20494 mv
      17/08/10 04:24:45.475  [INFO ] SCD10Appli Perf EvPending=0/350
      17/08/10 04:24:53.131  [WARN ] SCD10Appli BEARER LIMITED UP
      17/08/10 04:24:53.147  [INFO ] SCD10Appli #URC:+CIEV: service,0
      17/08/10 04:24:54.803  [INFO ] SCD10Appli ----10s----
      17/08/10 04:24:55.240  [INFO ] SCD10Appli MBat=20494 mv
      17/08/10 04:24:55.240  [INFO ] SCD10Appli Perf EvPending=0/350
      17/08/10 04:25:04.787  [INFO ] SCD10Appli ----10s----
      17/08/10 04:25:05.225  [INFO ] SCD10Appli MBat=20494 mv
      17/08/10 04:25:05.225  [INFO ] SCD10Appli Perf EvPending=0/350
      17/08/10 04:25:05.240  [INFO ] SCD10Appli ----1MN----
      17/08/10 04:25:06.459  [WARN ] SCD10Appli  Device lost the GSM coverage
      17/08/10 04:25:07.647  [WARN ] SCD10Appli GSM RX signal is too low
      17/08/10 04:25:07.647  [INFO ] SCD10Appli GprsLockCheck (0/5
      17/08/10 04:25:07.647  [INFO ] SCD10Appli ----STATUS----
      17/08/10 04:25:07.647  [INFO ] SCD10Appli Mode:2
      17/08/10 04:25:07.647  [INFO ] SCD10Appli FIFO Disp:0 Sms:0 Trip: 0 Syst: 0
      17/08/10 04:25:07.647  [INFO ] SCD10Appli GpsOn:false ID:0 Nav:090710080634:+43.62641:+007.05020:003:019:+00185:331AB7:u:03
      17/08/10 04:25:07.647  [INFO ] SCD10Appli KON:false
      17/08/10 04:25:07.647  [INFO ] SCD10Appli Diag:true
      17/08/10 04:25:07.647  [INFO ] SCD10Appli Creg=0
      17/08/10 04:25:07.647  [INFO ] SCD10Appli GsmLvl=0
      17/08/10 04:25:07.647  [INFO ] SCD10Appli CpinReady =true
      17/08/10 04:25:07.647  [INFO ] SCD10Appli Cfun=1
      17/08/10 04:25:07.647  [INFO ] SCD10Appli SmsSim=0
      17/08/10 04:25:07.647  [INFO ] SCD10Appli 000100:0002FF:0004FF:000800:001003:002001:004000:008000:010001:020000:040000:080001:100002:2000FF
      17/08/10 04:25:07.647  [INFO ] SCD10Appli ATime=1442 mn
      17/08/10 04:25:07.647  [INFO ] SCD10Appli ADist=4700 m
      17/08/10 04:25:07.647  [INFO ] SCD10Appli IATime=86665952 ms
      17/08/10 04:25:07.647  [INFO ] SCD10Appli IADist=4768 m
      17/08/10 04:25:07.647  [INFO ] SCD10Appli MBat=20480 mv
      17/08/10 04:25:07.647  [INFO ] SCD10Appli BBat= 4074 mv
      17/08/10 04:25:07.647  [INFO ] SCD10Appli GprsLocks=0
      17/08/10 04:25:07.647  [INFO ] SCD10Appli Threads= 15 MemTotal=589824 MemFree=88524

       

      Regards

      Rosbif

      • Re: GPRS lock on TC65 and TC65i
        Newbie

        Hi Rosbif,

            This is a typical 'STUCK SIM' symptom, which we have seen for many years. I am jotting down the technical explanation and please check it with your technical counterparts:

         

        SIM vendor does not have access to HLR. HLR is strictly controlled by any operator. In my experience, no operator purges/unpurges the SIM if SIM is idle of couple of hours (24/48/72). To verify if CREG is giving the stale or accurate information,  please try to send the SMS to device and see if it gets delivered.

        As you indicated, device is moving across the europe, which means its hitting multiple operators. In GPRS world, if due to some reason, GPRS registration is denied on any network (due to many reasons like maintenance or wrong provisiong of network element), GPRS protocol stack goes out of order and it requires soft reset. This is as per GPRS protocol specifications.

         

         

        There are many such anomalies in GPRS/GSM world, which needs to be accounted for while designing the software.

        FYI, To assist the development community, we have recently release a software solution (www.jasperlink.com) which is capable of handling any such field anomaly and correct itself. It frees the application developer from nitty-gritty of wireless technology.

         

         

        Regards,

        Rakesh

        • Re: GPRS lock on TC65 and TC65i
          Newbie

          Hi Rakesh,
            Regarding the HLR, sorry, my explanation was not clear.
          Our SIM supplier is an operator that provides us with SIMs for european roaming.
          They provide us with information on SIMs registered or not on request. It is the VLR address where the SIM is registered that they purge after 24 hours for roaming SIM as they consider this information no longer reliable if the periodic location updates have not been performed.

           

          Regarding the GPRS stack getting out of order and needing a soft reset. This is interesting to us as we have noticed that some of the locked devices lost communication in areas where other devices changed networks so we are assuming that in these cases the network coverage was not strong enough to "hold on" to the device connetion.

           

          Do I understand you, that if the GPRS registrtion is denied from 1 operator, the device does not register to another network, but needs a reset?

          We have tried sending SMSs to locked devices if we notice the lock the same day. They are not delivered; a  "No paging response" reason code is received.

          If we try again on the same device an "Absent Subscriber" reason code is received.

           

          I have forwarded your link for the software download to our developemnt dept.

           

          Cinterion are running tests with our midlet. I'll post an update when results are received.

          Regards

           

          Matt

          • Re: GPRS lock on TC65 and TC65i
            Newbie

            Your understanding about the GPRS is correct.

             

            If you are getting ‘absent sub’, it confirms that device is not GSM registered.

             

            Next question would be, where is this device located and what operators and signal strength , it is seeing at that location.

             

            What was the data/log pattern prior to this STUCK state.

            • Re: GPRS lock on TC65 and TC65i
              Newbie

              Dear Rakesh, I know this has been discussed years ago and I don't even know if you're still here in this community. I need more info about what you mentioned here, any chance of getting in contact with you? Or anyone having knowledge about SIM / registration behaviour.

               

              Thanks S.