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Problem with TAU configuration for PSM mode

Hello,

Here is some information from my environment :

  1. nRF9160 DK
  2. SIM iBASIS 
  3. Country: Suisse
  4. Operator: Swissom AG 
  5. roaming mode
  6. Use LTE Link Monitor

I have some questions:

First, I configure the modem in PSM mode with a TAU of 3h and an active time of 0 sec:

We can see with the return of + CEREG that the Active time is indeed at 0 and the TAU (10min * 20 = 200min) 3.3 hours

When I read this information via the "AT%XMONITOR" command, the last two arguments are <Periodic-TAU-ext> and <Periodic-TAU>. Could someone explain to me the meaning and use of these please?

Here is my problem, I am trying to configure a TAU of 10min and an active time of 1 min:

And I end up with an inactive TAU ...

Is this due to the fact that iBASIS is limited? or Swisscom? or roaming mode?

Thank you in advance for your answers,

Have a good day !

Pierre

Parents
  • Hello Pierre,

    Well yes, the <Periodic-TAU-ext> parameter in %XMONITOR says ‘deactivated’, which is equal to what you received as answer in <Periodic-TAU> of +CEREG.

    But the <Periodic-TAU> value in %XMONITOR is ‘01001010’ (60min), which means your operator does not allow you the desired TAU of 10min but tells you it is 60min instead.

    My assumption here is:

    The first time you requested a TAU of 3h, the answer you got from the operator in +CEREG was ‘00010100’ (3.3h). Since 3.3h is greater than the max value you can receive as a <Periodic-TAU> argument in %XMONITOR (which is ‘01011111’ = 3.1h), the operator interprets your requested TAU as a <Periodic-TAU-ext> value.

    As mentioned before, the <Periodic-TAU> argument in +CEREG actually represents a <Periodic-TAU-ext> value. Since your request of 3h was interpreted as 3.3h by the operator, a <Periodic-TAU-ext> argument had to be used, which explains the answer of ‘00010100’ in +CEREG.

    Your second request of 10min was not interpreted as a <Periodic-TAU-ext> value by the operator though, which is why you received ‘11100000’ as answer in the <Periodic-TAU> field of +CEREG. Instead, you got the answer from the operator in the designated <Periodic-TAU> argument of %XMONITOR. This makes sense in a way, since <Periodic-TAU> actually not represents an extended value.

    I hope this was not too confusing after all. Unfortunately, there are no standards or common ways of use here. It is up to the operator itself and can differ quite a bit.

    Cheers!

    Markus

Reply
  • Hello Pierre,

    Well yes, the <Periodic-TAU-ext> parameter in %XMONITOR says ‘deactivated’, which is equal to what you received as answer in <Periodic-TAU> of +CEREG.

    But the <Periodic-TAU> value in %XMONITOR is ‘01001010’ (60min), which means your operator does not allow you the desired TAU of 10min but tells you it is 60min instead.

    My assumption here is:

    The first time you requested a TAU of 3h, the answer you got from the operator in +CEREG was ‘00010100’ (3.3h). Since 3.3h is greater than the max value you can receive as a <Periodic-TAU> argument in %XMONITOR (which is ‘01011111’ = 3.1h), the operator interprets your requested TAU as a <Periodic-TAU-ext> value.

    As mentioned before, the <Periodic-TAU> argument in +CEREG actually represents a <Periodic-TAU-ext> value. Since your request of 3h was interpreted as 3.3h by the operator, a <Periodic-TAU-ext> argument had to be used, which explains the answer of ‘00010100’ in +CEREG.

    Your second request of 10min was not interpreted as a <Periodic-TAU-ext> value by the operator though, which is why you received ‘11100000’ as answer in the <Periodic-TAU> field of +CEREG. Instead, you got the answer from the operator in the designated <Periodic-TAU> argument of %XMONITOR. This makes sense in a way, since <Periodic-TAU> actually not represents an extended value.

    I hope this was not too confusing after all. Unfortunately, there are no standards or common ways of use here. It is up to the operator itself and can differ quite a bit.

    Cheers!

    Markus

Children
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