FiPy trouble with CatM1 AND NBIoT



  • Hello all, could use some real help from the community.
    I've been trying for weeks (months maybe) to get my FiPy successfully connected to any LTE network in the US. Have tried numerous combinations of NBIoT with TMobile and Twilio NBIoT as well as CatM with AT&T and even 1oT (https://1ot.mobi) with the same results. Essentially after scouring the forums for the best debugging code, I encounter the same loop where I get this encouraging info:

    +--------------------------+--------------------+
    |            FSM           |        STATE       |
    +--------------------------+--------------------+
    | RRC TOP FSM              |CONNECTING          |
    | RRC SEARCH FSM           |CAMPED              |
    | RRC ACTIVE FSM           |WAIT_SMC            |
    | PMM PLMN FSM             |NORM_CAMPED         |
    | EMM MAIN FSM             |REGISTERED_INIT     |
    | EMM AUTH FSM             |KASME_DEFINED       |
    | EMM CONN FSM             |AS_ESTABLISHED      |
    | EMM TAU FSM              |NULL                |
    | EMM TEST FSM             |NULL                |
    | ESM BEARER FSM           |BEARER_NULL_PENDING_ACTIVE|
    | SMS MT FSM               |IDLE                |
    | SMS MO FSM               |IDLE                |
    | HP MAIN FSM              |IDLE                |
    | HP USIM FSM              |READY               |
    | HP SMS MO FSM            |IDLE                |
    | HP SMS MT FSM            |IDLE                |
    | HP CAT FSM               |IDLE                |
    +--------------------------+--------------------+ 
    

    Only to immediately receive:

    +--------------------------+--------------------+
      |            FSM           |        STATE       |
      +--------------------------+--------------------+
      | RRC TOP FSM              |SCANNING            |
      | RRC SEARCH FSM           |WAIT_CELL_ID        |
      | RRC ACTIVE FSM           |NULL                |
      | PMM PLMN FSM             |NORM_CAMPED         |
      | EMM MAIN FSM             |NULL                |
      | EMM AUTH FSM             |NULL                |
      | EMM CONN FSM             |NULL                |
      | EMM TAU FSM              |NULL                |
      | EMM TEST FSM             |NULL                |
      | ESM BEARER FSM           |BEARER_NULL         |
      | SMS MT FSM               |IDLE                |
      | SMS MO FSM               |IDLE                |
      | HP MAIN FSM              |IDLE                |
      | HP USIM FSM              |READY               |
      | HP SMS MO FSM            |IDLE                |
      | HP SMS MT FSM            |IDLE                |
      | HP CAT FSM               |IDLE                |
      +--------------------------+--------------------+
    

    It looks like the modem finds a tower, tried to negotiate and then drops and camps.

    Here is a video of the loop I've been seeing for weeks across a miriad of different networks and SIMs.
    Any ideas???
    Really eager to get this working as we're interested in testing cellular as a failover protocol if Lora fails.

    Pycom Console terminal readout video



  • @Gijs Thanks. Emailed you just now.

    Meantime, I don't want to give up hope as this user seems to have made this work somehow:

    https://stackoverflow.com/questions/62791167/how-connect-to-lte-cell-network-with-pycom-fipy


  • Global Moderator

    Hi,
    Thanks @claus for the great advice!~
    My knowledge of the whole LTE thing only goes as far as the guide in the documentation unfortunately. I know we are working on publishing new LTE modem firmwares (hang tight!) but I'm not sure that will solve the issue here (we did have some succes with a beta NB-IoT firmware for other customers, you could contact me at support@pycom.io and I could send it to you!)

    Gijs



  • @claus I had high hopes! Unfortunately I'm seeing the same. Thanks for all your help!

    Starting ..
    rsrp [ -122.8 , -92.80001 ] center: -107.8
    rsrq [ -22.2 , -7.2 ] center: -14.7
    init lte
    reset lte
    cereg ['2', '0']
    attaching..
    .
     ('STOPPED', 'NULL').
     ('SCANNING', 'WAIT_CELL_ID')...
     ('SYNCING', 'WAIT_SYNC')...........
     ('CAMPING', 'WAIT_SIBX').
     ('CONNECTING', 'CAMPED').....
     ('SYNCING', 'WAIT_SYNC')....
     ('SCANNING', 'WAIT_CELL_ID')..
     ('CAMPING', 'WAIT_SIB').
     ('SCANNING', 'WAIT_RSSI')..........................................
     ('SCANNING', 'WAIT_CELL_ID').........
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC').........
     ('CONNECTING', 'CAMPED').....
     ('SYNCING', 'WAIT_SYNC').
     ('SCANNING', 'WAIT_CELL_ID').
     ('SYNCING', 'WAIT_SYNC')....
     ('SCANNING', 'WAIT_CELL_ID').
     ('SYNCING', 'WAIT_SYNC').
     ('SCANNING', 'WAIT_RSSI')..........................................
     ('SCANNING', 'WAIT_CELL_ID').........
     ('SYNCING', 'WAIT_SYNC').....
     ('CONNECTING', 'CAMPED')......
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC')..
     ('SCANNING', 'WAIT_CELL_ID')...
     ('SYNCING', 'WAIT_SYNC')..
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC').
     ('SCANNING', 'WAIT_RSSI')..........................................
     ('SCANNING', 'WAIT_CELL_ID').........
     ('SYNCING', 'WAIT_SYNC').
     ('SCANNING', 'WAIT_CELL_ID')..
     ('SYNCING', 'WAIT_SYNC').....
     ('SCANNING', 'WAIT_RSSI').........................................
     ('SCANNING', 'WAIT_CELL_ID')..........
     ('SYNCING', 'WAIT_SYNC')..
     ('CAMPING', 'WAIT_SIB').
     ('CONNECTING', 'CAMPED').
     ('SCANNING', 'WAIT_CELL_ID').....
     ('SYNCING', 'WAIT_SYNC')....
     ('CONNECTING', 'CAMPED').
     ('SCANNING', 'WAIT_CELL_ID')...
     ('SYNCING', 'WAIT_SYNC')...
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC')..
     ('SCANNING', 'WAIT_RSSI')..........................................
     ('SCANNING', 'WAIT_CELL_ID').......
     ('SYNCING', 'WAIT_SYNC').
     ('CAMPING', 'WAIT_SIB')...
     ('CAMPING', 'WAIT_SIBX').
     ('CAMPED', 'CAMPED_ANY').........
     ('SCANNING', 'WAIT_CELL_ID')..
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC')...
     ('SCANNING', 'WAIT_RSSI')..........................................
     ('SCANNING', 'WAIT_CELL_ID').......
     ('SYNCING', 'WAIT_SYNC').....
     ('CAMPED', 'CAMPED_ANY')............
     ('SCANNING', 'WAIT_CELL_ID').
     ('SYNCING', 'WAIT_SYNC').
     ('SCANNING', 'WAIT_RSSI')..........................................
     ('SCANNING', 'WAIT_CELL_ID').......
     ('SYNCING', 'WAIT_SYNC')...
     ('CAMPING', 'WAIT_SIB')..
     ('CAMPING', 'WAIT_SIBX').
     ('CAMPED', 'CAMPED_ANY')............
     ('SCANNING', 'WAIT_CELL_ID').
     ('SYNCING', 'WAIT_SYNC')..
     ('CAMPING', 'WAIT_SIB').
     ('SCANNING', 'WAIT_RSSI')..........................................
     ('SCANNING', 'WAIT_CELL_ID')........
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC')......
     ('CAMPED', 'CAMPED_ANY')...........
     ('RESEL', 'WAIT_SIB').
     ('RESEL', 'WAIT_CELL_ID')..
     ('RESEL', 'WAIT_SYNC').
     ('CAMPED', 'CAMPED_ANY').................................
    

    Perhaps there is a deeper issue with the modem firmware that only Pycom can help diagnose. @Gijs or @administrators Can you recommend some next steps to diagnose my problems?



  • @claus Thanks for your help! I'll give your code a shot



  • @barryjump For testing the attach process I use https://github.com/clausdenk/fipy-ltesignal. You should be able to use it directly by commenting the dnsserver calls at the top of the file and adjusting ATTACH_PARAMETERS. It should be ok to only specify the apn, the band should be detected automatically by the modem. If you know the band it probably speeds up the process though. I get outputs similar to

     ('SCANNING', 'WAIT_CELL_ID').
     ('CAMPING', 'WAIT_SIBX')..
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC').
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC').
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC').
     ('CAMPING', 'WAIT_SIBX').........
     ('CONNECTING', 'CAMPED')...
     ('CONNECTED', 'CAMPED')......attached!
    rsrp,rsrq,<rsrp>,<rsrq>: -113.33 -15.89 -113.33 -15.89
    rsrp,rsrq,<rsrp>,<rsrq>: -113.19 -15.96 -113.26 -15.925
    ...
    

    I just had a problem with the CEREG setting !=2 and setting it to 2 fixed it for me. A pity it does not in your case.



  • @claus Would you be willing to share your main.py here? I'm increasingly thinking that I have the band, apn, or carrier setup wrong.



  • @claus said in FiPy trouble with CatM1 AND NBIoT:

    AT+CEREG?

    Thanks @claus running that check showed the following:

    Sent to modem: 'AT+CEREG?'
    +CEREG: 2,0
    OK
    ********************
    

    Which means it was already configured with that value. I did notice it got to connecting a bit faster than usual this time, but same problem: from connecting to searching almost immediately. :(

    Pybytes configuration read from /flash/pybytes_config.json
    Not starting Pybytes as auto-start is disabled
    Sent to modem: 'ATI1'
    UE5.0.0.0d
    LR5.1.1.0-41065
    OK
    Sent to modem: 'AT!="showver"'
    SYSTEM VERSION
    ==============
      FIRMWARE VERSION
        Bootloader0  : 5.1.1.0 [39529]
        Bootloader1* : 5.1.1.0 [41065]
        Bootloader2  : 6.0.0.0 [41019]
        NV Info      : 1.1,0,0
        Software     : 5.1.1.0 [41065] by robot-soft at 2018-12-17 13:03:40
        UE           : 5.0.0.0d
      COMPONENTS
        ZSP0         : 1.0.99-13616
        ZSP1         : 1.0.99-12376
    OK
    Sent to modem: 'AT!="RRC:setDbgPerm full"'
    OK
    Sent to modem: 'AT!="RRC:showcaps"'
    == CAPS config =============================
      .Lock UE on SRV band    : false
      .MFBI support           : true
      .TM8 TDD support        : false
    ============================================
    == CAPS ====================================
      . access stratum: R13
      . catM          : 1
      . nb-IoT        : 0
    -- EUTRA bands --
      . supported     : 66/28/26/25/20/19/18/17/14/13/12/8/5/4/3/2/1
      . board         : 1/2/3/4/5/8/12/13/14/17/18/19/20/25/26/28/66
      . admin         : 
      . pending admin : 
    -- EUTRA carriers --
      . admin         : 
      . pending admin : 
    ============================================
    OK
    Sent to modem: 'AT+SQNCTM?'
    +SQNCTM: standard
    OK
    Booting up... 
    10
    9
    8
    7
    6
    5
    4
    3
    2
    1
    No user input detected, starting
    Attempting LTE connect with:
    APN: terminal
    IMEI  35434*********
    ICCID  89310**************
    Sent to modem: 'AT+CEREG?'
    +CEREG: 2,0
    OK
    ********************
    attaching...Sent to modem: 'AT!="showphy"'
    DL SYNCHRO STATISTICS
    =====================
        Synchro state                         : CELL_ACQUIRED
        PPU SIB1 ACQ watchdog                 : 0
        Frequency Hypothesis RF  (Hz)         : 0
        RSRP (dBm)                            : -108.60
        RSRQ  (dB)                            : -10.81
        Channel estimation state (Cell-spec.) : HIGH CINR
        Channel estimation state (UE-spec.)   : LOW CINR
        Channel estimation state (MBSFN)      : LOW CINR
        Channel estimation CINR               : 5.82
        Channel length                        : SHORT
      AGC
        AGC RX gain (dB)                      : 59.61
        RX PSD BO (dBFs)                      : -21.00
        RX PSD (dBm)                          : -110.93
        Noise level RS (dBm)                  : -114.30
        Digital gain (dB)                     : 14.73
        CINR RS (dB)                          : 5.70
      NARROWBANDS
        Last DL NB                            : 3
        Last UL NB                            : N/A
      AFC
        Frequency offset RF  (Hz)             : -475
        Frequency offset BB  (Hz)             : 0
      PBCH
        MIB received quantity                 : 66
        MIB timeout quantity                  : 0
    OK
    Sent to modem: 'AT!="fsm"'
    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |CONNECTING          |
        | RRC SEARCH FSM           |CAMPED              |
        | RRC ACTIVE FSM           |WAIT_SMC            |
        | PMM PLMN FSM             |NORM_CAMPED         |
        | EMM MAIN FSM             |REGISTERED_INIT     |
        | EMM AUTH FSM             |WAITING_SIM_CONFIRM |
        | EMM CONN FSM             |AS_ESTABLISHED      |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_NULL_PENDING_ACTIVE|
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    OK
    .Sent to modem: 'AT!="showphy"'
    DL SYNCHRO STATISTICS
    =====================
        Synchro state                         : CELL_ACQUIRED
        PPU SIB1 ACQ watchdog                 : 0
        Frequency Hypothesis RF  (Hz)         : 0
        RSRP (dBm)                            : -108.99
        RSRQ  (dB)                            : -11.66
        Channel estimation state (Cell-spec.) : LOW CINR
        Channel estimation state (UE-spec.)   : LOW CINR
        Channel estimation state (MBSFN)      : LOW CINR
        Channel estimation CINR               : 5.14
        Channel length                        : SHORT
      AGC
        AGC RX gain (dB)                      : 59.61
        RX PSD BO (dBFs)                      : -20.81
        RX PSD (dBm)                          : -109.95
        Noise level RS (dBm)                  : -114.09
        Digital gain (dB)                     : 13.75
        CINR RS (dB)                          : 5.10
      NARROWBANDS
        Last DL NB                            : 3
        Last UL NB                            : N/A
      AFC
        Frequency offset RF  (Hz)             : -492
        Frequency offset BB  (Hz)             : 0
      PBCH
        MIB received quantity                 : 66
        MIB timeout quantity                  : 0
    OK
    Sent to modem: 'AT!="fsm"'
    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |CONNECTING          |
        | RRC SEARCH FSM           |CAMPED              |
        | RRC ACTIVE FSM           |WAIT_SMC            |
        | PMM PLMN FSM             |NORM_CAMPED         |
        | EMM MAIN FSM             |REGISTERED_INIT     |
        | EMM AUTH FSM             |KASME_DEFINED       |
        | EMM CONN FSM             |AS_ESTABLISHED      |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_NULL_PENDING_ACTIVE|
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    OK
    .Sent to modem: 'AT!="showphy"'
    DL SYNCHRO STATISTICS
    =====================
        Synchro state                         : CELL_SEARCH
        PPU SIB1 ACQ watchdog                 : 0
        Frequency Hypothesis RF  (Hz)         : 0
        RSRP (dBm)                            : -21474836.00
        RSRQ  (dB)                            : -11.97
        Channel estimation state (Cell-spec.) : LOW CINR
        Channel estimation state (UE-spec.)   : LOW CINR
        Channel estimation state (MBSFN)      : LOW CINR
        Channel estimation CINR               : 4.30
        Channel length                        : SHORT
      AGC
        AGC RX gain (dB)                      : 59.59
        RX PSD BO (dBFs)                      : -20.54
        RX PSD (dBm)                          : -105.79
        Noise level RS (dBm)                  : -128.24
        Digital gain (dB)                     : 5.41
        CINR RS (dB)                          : -0.01
      NARROWBANDS
        Last DL NB                            : Central
        Last UL NB                            : 0
      AFC
        Frequency offset RF  (Hz)             : -480
        Frequency offset BB  (Hz)             : 0
      PBCH
        MIB received quantity                 : 73
        MIB timeout quantity                  : 0
    OK
    Sent to modem: 'AT!="fsm"'
    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |SYNCING             |
        | RRC SEARCH FSM           |WAIT_SYNC           |
        | RRC ACTIVE FSM           |NULL                |
        | PMM PLMN FSM             |NORM_CAMPED         |
        | EMM MAIN FSM             |NULL                |
        | EMM AUTH FSM             |NULL                |
        | EMM CONN FSM             |NULL                |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_NULL         |
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    OK
    .Sent to modem: 'AT!="showphy"'
    DL SYNCHRO STATISTICS
    =====================
        Synchro state                         : RSRP
        PPU SIB1 ACQ watchdog                 : 0
        Frequency Hypothesis RF  (Hz)         : -1000
        RSRP (dBm)                            : -21474836.00
        RSRQ  (dB)                            : -11.97
        Channel estimation state (Cell-spec.) : HIGH CINR
        Channel estimation state (UE-spec.)   : LOW CINR
        Channel estimation state (MBSFN)      : LOW CINR
        Channel estimation CINR               : 7.20
        Channel length                        : SHORT
      AGC
        AGC RX gain (dB)                      : 59.59
        RX PSD BO (dBFs)                      : -19.92
        RX PSD (dBm)                          : -103.98
        Noise level RS (dBm)                  : -128.24
        Digital gain (dB)                     : 7.80
        CINR RS (dB)                          : -0.01
      NARROWBANDS
        Last DL NB                            : Central
        Last UL NB                            : 0
      AFC
        Frequency offset RF  (Hz)             : 513
        Frequency offset BB  (Hz)             : 0
      PBCH
        MIB received quantity                 : 92
        MIB timeout quantity                  : 0
    OK
    Sent to modem: 'AT!="fsm"'
    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |SCANNING            |
        | RRC SEARCH FSM           |WAIT_CELL_ID        |
        | RRC ACTIVE FSM           |NULL                |
        | PMM PLMN FSM             |NORM_CAMPED         |
        | EMM MAIN FSM             |NULL                |
        | EMM AUTH FSM             |NULL                |
        | EMM CONN FSM             |NULL                |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_NULL         |
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    OK
    .Sent to modem: 'AT!="showphy"'
    DL SYNCHRO STATISTICS
    =====================
        Synchro state                         : CELL_SEARCH
        PPU SIB1 ACQ watchdog                 : 0
        Frequency Hypothesis RF  (Hz)         : -1000
        RSRP (dBm)                            : -21474836.00
        RSRQ  (dB)                            : -11.97
        Channel estimation state (Cell-spec.) : LOW CINR
        Channel estimation state (UE-spec.)   : LOW CINR
        Channel estimation state (MBSFN)      : LOW CINR
        Channel estimation CINR               : 1.74
        Channel length                        : SHORT
      AGC
        AGC RX gain (dB)                      : 55.73
        RX PSD BO (dBFs)                      : -33.26
        RX PSD (dBm)                          : -123.33
        Noise level RS (dBm)                  : -128.24
        Digital gain (dB)                     : 9.27
        CINR RS (dB)                          : -0.01
      NARROWBANDS
        Last DL NB                            : Central
        Last UL NB                            : 0
      AFC
        Frequency offset RF  (Hz)             : -421
        Frequency offset BB  (Hz)             : 0
      PBCH
        MIB received quantity                 : 116
        MIB timeout quantity                  : 0
    OK
    Sent to modem: 'AT!="fsm"'
    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |SCANNING            |
        | RRC SEARCH FSM           |WAIT_CELL_ID        |
        | RRC ACTIVE FSM           |NULL                |
        | PMM PLMN FSM             |NORM_CAMPED         |
        | EMM MAIN FSM             |NULL                |
        | EMM AUTH FSM             |NULL                |
        | EMM CONN FSM             |NULL                |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_NULL         |
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    OK
    


  • @barryjump Your signal strength should not be a problem, I have RSRP around -115 and RSRQ at -15 and I can attach. Could you please check the following: Print the output of the AT command "AT+CEREG?" after lte.init(). If the first integer value is different from "2" ( say for example "+CEREG: 0,2" - the first value is "0") then include a "AT+CEREG=2" after lte.init(). Your "AT+CEREG?" should now give "+CEREG: 2,x". Now try to attach.



  • Quick update, I brought my FiPy on the road and parked right beneath a cell tower to see if perhaps my problem originated from poor signal.

    As I mentioned before, my original signal reported as follows:
    RSRQ (dB) : -10.82 (-3 Excellent to -19 Poor)
    RSRP (dBm) : -104.80 (-44 Excellent to -140 Poor)
    CINR : 10.31 (12.5 Excellent to 7 Poor)

    Underneath the tower I was seeing excellent signal stats:
    RSRQ (dB) : -6.2 (-3 Excellent to -19 Poor)
    RSRP (dBm) : -59.02 (-44 Excellent to -140 Poor)
    CINR : 28.22 (12.5 Excellent to 7 Poor)

    Unfortunately that did not resolve the issue, so all I can imagine I'm left with is some configuration problems with the Band, APN, or Network settings in lte.init() and lte.attach(). Perhaps @Gijs you have some suggestions?

    Thanks!



  • @Gijs this is my code, I've tried several different APNs, but perhaps I've set this up wrong? One thing I may not be handling properly is the band and carrier, but that is a bit strange considering we've been testing MVNOs (like Hologram, Twilio, Soracom, etc.) that hop different carriers with different bands. I've left the band unspecified as a result - perhaps thats incorrect.

    ######################################
    #           LTE Setup
    ######################################
    
    lte = LTE()
    apn = "terminal"  ## per https://1ot.mobi
    band = "None"
    iccid = lte.iccid()
    imei = lte.imei()
    
    
    def send_at_cmd_pretty(cmd):
        response = lte.send_at_cmd(cmd).split('\r\n')
        print('Sent to modem: \'{}\''.format(cmd))
        for line in response:
            if line.strip() != '':
                print(line)
    
    # MODEM DEBUG
    send_at_cmd_pretty('ATI1')                                      # retrieve modem firmware
    send_at_cmd_pretty('AT!="showver"')                             # retrieve modem firmware
    send_at_cmd_pretty('AT!="RRC:setDbgPerm full"')
    send_at_cmd_pretty('AT!="RRC:showcaps"')
    time.sleep(5)
    send_at_cmd_pretty('AT+SQNCTM?')
    
    def lteconnect():
        print("Attempting LTE connect with:")
        print("APN: %s" % apn)
        print('IMEI ', lte.imei()[:5] + '*' * 9)
        print('ICCID ', lte.iccid()[:5] + '*' * 14)
        time.sleep(3)
    
        # Initialize the modem
        lte.init()
    
        # Attach the modem
        lte.attach(apn="terminal") 
        print("attaching..",end='')
    
        while not lte.isattached():
            # JFD time.delay(0.25)
            pycom.rgbled(0x500000)
            utime.sleep_ms(25)
            print('.',end='')
            send_at_cmd_pretty('AT!="showphy"')
            send_at_cmd_pretty('AT!="fsm"')
            #utime.sleep_ms(500)
            #print(lte.send_at_cmd('print'))
            utime.sleep_ms(500)
    
        pycom.rgbled(0x005000)
        print("attached!")
    
        lte.connect()
        print("connecting [##",end='')
        while not lte.isconnected():
            # JFD time.sleep(0.25)
            utime.sleep_ms(250)
            print('#',end='')
            #print(lte.send_at_cmd('AT!="showphy"'))
            print(lte.send_at_cmd('AT!="fsm"'))
            print(lte.send_at_cmd("ATI"))
        print("] connected!")
    
        # JFD Add delay
        utime.sleep_ms(250)
    
        # Ping Google server to test  
        print(usocket.getaddrinfo('google.com', 80))  
        print("Waiting for 60 seconds before disconnecting ...")
        time.sleep(60)
        print("OK, disconnecting now.")
        lte.deinit()
        #now we can safely machine.deepsleep()
    

  • Global Moderator

    Hi,
    So it seems you are connecting (which is good!) but then immediately being rejected by the network because of some settings mismatch probably. There could be several causes for this error (mismatch in APN, simcard, sudden loss of signal etc.)



  • @claus Hey I tripped checked sim card placement and firmware. Regarding signal and network availability, I found this reference elsewhere on this forum.

    https://usatcorp.com/faqs/understanding-lte-signal-strength-values/

    If this reference doc is correct, my results (at the time FSM shows Connecting) show that I while don't have great signal, I should have enough to reach a tower.

    RSRQ (dB) : -10.82 (-3 Excellent to -19 Poor)
    RSRP (dBm) : -104.80 (-44 Excellent to -140 Poor)
    CINR : 10.31 (12.5 Excellent to 7 Poor)

    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |CONNECTING          |
        | RRC SEARCH FSM           |CAMPED              |
        | RRC ACTIVE FSM           |WAIT_SMC            |
        | PMM PLMN FSM             |NORM_CAMPED         |
        | EMM MAIN FSM             |REGISTERED_INIT     |
        | EMM AUTH FSM             |NULL                |
        | EMM CONN FSM             |AS_ESTABLISHED      |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_NULL_PENDING_ACTIVE|
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    OK
    .Sent to modem: 'AT!="showphy"'
    DL SYNCHRO STATISTICS
    =====================
        Synchro state                         : CELL_ACQUIRED
        PPU SIB1 ACQ watchdog                 : 0
        Frequency Hypothesis RF  (Hz)         : 0
        RSRP (dBm)                            : -104.80
        RSRQ  (dB)                            : -10.82
        Channel estimation state (Cell-spec.) : HIGH CINR
        Channel estimation state (UE-spec.)   : LOW CINR
        Channel estimation state (MBSFN)      : LOW CINR
        Channel estimation CINR               : 10.31
        Channel length                        : SHORT
      AGC
        AGC RX gain (dB)                      : 59.51
        RX PSD BO (dBFs)                      : -21.19
        RX PSD (dBm)                          : -107.63
        Noise level RS (dBm)                  : -114.59
        Digital gain (dB)                     : 11.53
        CINR RS (dB)                          : 9.79
      NARROWBANDS
        Last DL NB                            : 0
        Last UL NB                            : N/A
      AFC
        Frequency offset RF  (Hz)             : -492
        Frequency offset BB  (Hz)             : 0
      PBCH
        MIB received quantity                 : 49
        MIB timeout quantity                  : 0
    OK
    Sent to modem: 'AT!="fsm"'
    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |CONNECTING          |
        | RRC SEARCH FSM           |CAMPED              |
        | RRC ACTIVE FSM           |WAIT_SMC            |
        | PMM PLMN FSM             |NORM_CAMPED         |
        | EMM MAIN FSM             |REGISTERED_INIT     |
        | EMM AUTH FSM             |KASME_DEFINED       |
        | EMM CONN FSM             |AS_ESTABLISHED      |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_NULL_PENDING_ACTIVE|
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    OK
    .Sent to modem: 'AT!="showphy"'
    DL SYNCHRO STATISTICS
    =====================
        Synchro state                         : SIB1_ACQ
        PPU SIB1 ACQ watchdog                 : 0
        Frequency Hypothesis RF  (Hz)         : 0
        RSRP (dBm)                            : -104.71
        RSRQ  (dB)                            : -11.23
        Channel estimation state (Cell-spec.) : HIGH CINR
        Channel estimation state (UE-spec.)   : LOW CINR
        Channel estimation state (MBSFN)      : LOW CINR
        Channel estimation CINR               : 11.44
        Channel length                        : SHORT
      AGC
        AGC RX gain (dB)                      : 59.51
        RX PSD BO (dBFs)                      : -20.95
        RX PSD (dBm)                          : -107.41
        Noise level RS (dBm)                  : -114.74
        Digital gain (dB)                     : 11.31
        CINR RS (dB)                          : 10.03
      NARROWBANDS
        Last DL NB                            : Central
        Last UL NB                            : N/A
      AFC
        Frequency offset RF  (Hz)             : -493
        Frequency offset BB  (Hz)             : 0
      PBCH
        MIB received quantity                 : 56
        MIB timeout quantity                  : 0
    OK
    Sent to modem: 'AT!="fsm"'
    SYSTEM FSM
    ==========
        +--------------------------+--------------------+
        |            FSM           |        STATE       |
        +--------------------------+--------------------+
        | RRC TOP FSM              |SYNCING             |
        | RRC SEARCH FSM           |WAIT_SYNC           |
        | RRC ACTIVE FSM           |NULL                |
        | PMM PLMN FSM             |NORM_CAMPED         |
        | EMM MAIN FSM             |NULL                |
        | EMM AUTH FSM             |NULL                |
        | EMM CONN FSM             |NULL                |
        | EMM TAU FSM              |NULL                |
        | EMM TEST FSM             |NULL                |
        | ESM BEARER FSM           |BEARER_NULL         |
        | SMS MT FSM               |IDLE                |
        | SMS MO FSM               |IDLE                |
        | HP MAIN FSM              |IDLE                |
        | HP USIM FSM              |READY               |
        | HP SMS MO FSM            |IDLE                |
        | HP SMS MT FSM            |IDLE                |
        | HP CAT FSM               |IDLE                |
        +--------------------------+--------------------+
    OK
    .Sent to modem: 'AT!="showphy"'
    DL SYNCHRO STATISTICS
    =====================
        Synchro state                         : FRAME_UPDATE
        PPU SIB1 ACQ watchdog                 : 0
        Frequency Hypothesis RF  (Hz)         : 0
        RSRP (dBm)                            : -21474836.00
        RSRQ  (dB)                            : -11.23
        Channel estimation state (Cell-spec.) : HIGH CINR
        Channel estimation state (UE-spec.)   : LOW CINR
        Channel estimation state (MBSFN)      : LOW CINR
        Channel estimation CINR               : 7.97
        Channel length                        : SHORT
      AGC
        AGC RX gain (dB)                      : 59.51
        RX PSD BO (dBFs)                      : -21.32
        RX PSD (dBm)                          : -110.56
        Noise level RS (dBm)                  : -128.24
        Digital gain (dB)                     : 5.49
        CINR RS (dB)                          : 10.03
      NARROWBANDS
        Last DL NB                            : Central
        Last UL NB                            : N/A
      AFC
        Frequency offset RF  (Hz)             : -483
        Frequency offset BB  (Hz)             : 0
      PBCH
        MIB received quantity                 : 70
        MIB timeout quantity                  : 0
    OK
    


  • @claus I did check both, but I'm going to double and triple check now. Will report back.
    Thanks for helping!



  • @barryjump These are the states I get after a lte.reset():

    init lte
    reset lte
    attaching..
     ('SCANNING', 'WAIT_CELL_ID').
     ('CAMPING', 'WAIT_SIB').
     ('CAMPING', 'WAIT_SIBX').
     ('CAMPING', 'WAIT_SIB').
     ('SYNCING', 'WAIT_SYNC')....
     ('CAMPING', 'WAIT_SIB').
     ('CAMPING', 'WAIT_SIBX')...
     ('CONNECTING', 'CAMPED')......
     ('CONNECTED', 'CAMPED')........................attached!
    

    Your states look exactly like what I had before changing the modem firmware. The docs say

    If the system returns multiple times from SYNCING to CAMPED, check the network availability, simcard placement and / or the firmware version. 
    

    You have checked the other two hints I guess? Has 1oT provided you with the band and apn parameters?



  • Thanks for the reply @claus. I did indeed update the modem firmware. First update was from stock firmware to latest NBIoT (6.0.x etc) and tested with NB specific SIM from Twilio without success. Then recently switched to latest CatM firmware and tested with CatM specific SIM from 1oT.

    Cylce as follows:

    RCC_TOP_FSM: Scanning
    RRC_SEARCH_FSM: Wait cell ID

    RCC_TOP_FSM: Syncing
    RRC_SEARCH_FSM: Wait Sync

    RCC_TOP_FSM: Connecting
    RRC_SEARCH_FSM: Camped

    RCC_TOP_FSM: Scanning
    RRC_SEARCH_FSM: Wait cell ID

    RCC_TOP_FSM: Syncing
    RRC_SEARCH_FSM: Wait Sync

    RCC_TOP_FSM: Connecting
    RRC_SEARCH_FSM: Camped

    RCC_TOP_FSM: Camping
    RRC_SEARCH_FSM: Wait SIB1

    RCC_TOP_FSM: Syncing
    RRC_SEARCH_FSM: Wait Sync

    RCC_TOP_FSM: Scanning
    RRC_SEARCH_FSM: Wait RSSI

    And on and on.

    It seems to enter Connecting state very quickly after reinitializing modem. But only stays there for a few seconds before bailing to the other states (Syncing, Scanning, etc).



  • @barryjump Have you changed your modem firmware accordingly when switching from Cat-M1 to NB-IoT? I had a similar problem and the cause was that the device came with Cat-M1 firmware shipped, but my SIM was NB-IoT. Also, check the "LTE Troubleshooting guide at https://docs.pycom.io/tutorials/networks/lte/, it gives a few solutions to common cases. I could not see your video, you should describe what the first 2 fields are doing (RRC_TOP_FSM and RRC_SEARCH_FSM).


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