T-Mobile NB-IoT in the Netherlands? [SOLVED]

nadvorvo

Hi @Gijs,
I really appreciate the support you’ve given me. Sorry for some delays (I was out of office several days).

I am now trying to downgrade to 1.20.2.r1 ... as you know I have some troubles:
https://forum.pycom.io/topic/1735/failed-to-connect-to-esp32-invalid-head-of-packet-x08/6

Today I have made some test with NB-IoT.
I have noticed weak signal:

>>> lte.send_at_cmd('AT+CSQ')
'\r+CSQ: 18,99\r\rOK\r'

rssi=18 ... -77dBm
Below -70 dBm: Signal is too weak, subject to external interference
Today even I could not attach (usually it takes few seconds and I get lte.isattached() = true). Could it be hint why AT+PING command get error?

>>> from network import LTE
>>> lte = LTE()
>>> lte.attach(band=20, apn="nb.zoocontrol")
>>> lte.isattached()
False

Thank you in advance for your assistance.
Regards, Vojtech

nadvorvo

Hi @Gijs,
finally I have to downgrade to 1.20.2.r1
Then I have executed testing code. Still having problems with attaching (pls see my last post regarding rssi).

Thank you in advance for your assistance.
Regards, Vojtech

>>> exec(open('./lte_test.py').read())
Sysname: GPy
Release: 1.20.2.r1
Version: v1.11-a5aa0b8 on 2020-09-09
Machine: GPy with ESP32
Query LTE modem imei... 35434**********
Query SIM iccid... 89882***************
Sent to modem: 'ATI1', delay 1000 ms
UE6.0.0.0
LR6.0.0.0-41019
OK
Sent to modem: 'AT!="showver"', delay 1000 ms
SYSTEM VERSION
==============
  FIRMWARE VERSION
    Bootloader0  : 5.1.1.0 [41065]
    Bootloader1* : 6.0.0.0 [41019]
    Bootloader2  : 5.1.1.0 [41065]
    NV Info      : 1.1,0,0
    Software     : 6.0.0.0 [41019] by robot-soft at 2018-12-13 21:41:15
    UE           : 6.0.0.0
  COMPONENTS
    ZSP0         : 1.0.99-3171
    ZSP1         : 1.0.98-3170
OK
Sent to modem: 'AT!="RRC:setDbgPerm full"', delay 1000 ms
OK
Sent to modem: 'AT!="RRC:showcaps"', delay 1000 ms
== CAPS config =============================
  .Lock UE on SRV band    : false
  .MFBI support           : true
  .TM8 TDD support        : false
============================================
== CAPS ====================================
  . access stratum: R13
  . catM          : 1
  . nb-IoT        : 1
-- 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?', delay 1000 ms
+SQNCTM: standard
OK
LTE attaching...
Attaching... 1
Attaching... 2
Attaching... 3
Attaching... 4
Attaching... 5
Attaching... 6
Attaching... 7
Attaching... 8
Attaching... 9
Attaching... 10
Attaching... 11
Attaching... 12
Attaching... 13
Attaching... 14
Attaching... 15

robert-hh

@nadvorvo I'm just using lte.attach() here with a T-Mobile NB-IoT card. attaching usually takes 12 seconds, but sometimes much longer. The response to AT+CSQ is 25,99. I'm using MicroPython 1.20.2.rc11, and the latest modem firmware 41019, and the same bootloader.
Ping to 172.27.131.100 fails in a proper manner with error, ping to e.g. 217.160.86.40 or 8.8.8.8 works.
Maybe you have a problem with the antenna or reception. Can you move close to a window?

nadvorvo

Hi @Gijs,
Today I have sold problem with lte.attach(). It was necessary to add before (select network operator):

lte.send_at_cmd('AT+COPS=1,2,"23003"')

Ping not working even after FW downgrade to 1.20.2.r1.
Thank you in advance for your assistance.
Regards, Vojtech

>>> exec(open('./lte_test.py').read())
Sysname: GPy
Release: 1.20.2.r1
Version: v1.11-a5aa0b8 on 2020-09-09
Machine: GPy with ESP32
Query LTE modem imei... 35434**********
Query SIM iccid... 89882***************
Sent to modem: 'ATI1', delay 1000 ms
UE6.0.0.0
LR6.0.0.0-41019
OK
Sent to modem: 'AT!="showver"', delay 1000 ms
SYSTEM VERSION
==============
  FIRMWARE VERSION
    Bootloader0  : 5.1.1.0 [41065]
    Bootloader1* : 6.0.0.0 [41019]
    Bootloader2  : 5.1.1.0 [41065]
    NV Info      : 1.1,0,0
    Software     : 6.0.0.0 [41019] by robot-soft at 2018-12-13 21:41:15
    UE           : 6.0.0.0
  COMPONENTS
    ZSP0         : 1.0.99-3171
    ZSP1         : 1.0.98-3170
OK
Sent to modem: 'AT!="RRC:setDbgPerm full"', delay 1000 ms
OK
Sent to modem: 'AT!="RRC:showcaps"', delay 1000 ms
== CAPS config =============================
  .Lock UE on SRV band    : false
  .MFBI support           : true
  .TM8 TDD support        : false
============================================
== CAPS ====================================
  . access stratum: R13
  . catM          : 1
  . nb-IoT        : 1
-- 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?', delay 1000 ms
+SQNCTM: standard
OK
LTE attaching...
Attaching... 1
Attaching... 2
Attaching... 3
Attaching... 4
Attaching... 5
LTE attach succeeded!
Sent to modem: 'AT+CEREG?', delay 1000 ms
+CEREG: 2,5,"B7B6","0003E421",9
OK
Sent to modem: 'AT+SQNMONI=9', delay 1000 ms
+SQNMONI: Vodafone@ Cc:230 Nc:03 RSRP:-93.10 CINR:-0.90 RSRQ:-14.20 TAC:47030 Id:76 EARFCN:6447 PWR:-71.12 PAGING:256
OK
Sent to modem: 'AT+CSQ', delay 1000 ms
+CSQ: 20,99
OK
Sent to modem: 'AT!="showphy"', delay 1000 ms
DL SYNCHRO STATISTICS
=====================
    Synchro state                         : CELL_ACQUIRED
    PPU SIB1 ACQ watchdog                 : 1
    Frequency Hypothesis RF  (Hz)         : 0
    RSRP (dBm)                            : -93.51
    RSRQ  (dB)                            : -14.33
    Channel estimation state (Cell-spec.) : LOW CINR
    Channel estimation state (UE-spec.)   : LOW CINR
    Channel estimation state (MBSFN)      : LOW CINR
    Channel estimation CINR               : 0.05
    Channel length                        : SHORT
  AGC
    AGC RX gain (dB)                      : 55.79
    RX PSD BO (dBFs)                      : -20.32
    RX PSD (dBm)                          : -93.14
    Noise level RS (dBm)                  : -92.36
    Digital gain (dB)                     : 1.44
    CINR RS (dB)                          : -1.15
  NARROWBANDS
    Last DL NB                            : Central
    Last UL NB                            : 0
  AFC
    Frequency offset RF  (Hz)             : -524
    Frequency offset BB  (Hz)             : 0
  PBCH
    MIB received quantity                 : 0
    MIB timeout quantity                  : 0
OK
Sent to modem: 'AT!="fsm"', delay 1000 ms
SYSTEM FSM
==========
    +--------------------------+--------------------+
    |            FSM           |        STATE       |
    +--------------------------+--------------------+
    | RRC TOP FSM              |CONNECTED           |
    | RRC SEARCH FSM           |CAMPED              |
    | RRC ACTIVE FSM           |CONNECTED           |
    | PMM PLMN FSM             |NORM_CAMPED         |
    | EMM MAIN FSM             |REGISTERED          |
    | EMM AUTH FSM             |KASME_DEFINED       |
    | EMM CONN FSM             |AS_ESTABLISHED      |
    | EMM TAU FSM              |NULL                |
    | EMM TEST FSM             |NULL                |
    | ESM BEARER FSM           |BEARER_ACTIVE       |
    | SMS MT FSM               |IDLE                |
    | SMS MO FSM               |IDLE                |
    | LPP 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+CGPADDR', delay 1000 ms
+CGPADDR: 1,"10.0.1.197"
OK
Sent to modem: 'AT+PING="172.27.131.100"', delay 5000 ms
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<string>", line 64, in <module>
OSError: LTE modem version not read

Gijs

@nadvorvo said in T-Mobile NB-IoT in the Netherlands? [SOLVED]:

Thank you for your reply.

So we are back here again If im correct. I tested the AT+PING again om my devices and that seems to work fine (still!). I have asked @xykon to take a look as well, so we can figure this out!

Gijs

Gijs

Hi,
Sorry for the long delay, I have since looked at your code again, and the AT+PING does not return anything for you, try the following:lte = LTE(debug=True) which will give you more insight into the sent AT commands by the lte module.

The error is with the lte.connect() which has a version check, that receives a non-applicable response from the modem.

Next, I figured out that the AT+PING has no specified timeout. This will interfere with the next AT command called (ATI1) and cause the modem version not read error, as the AT+PING has still information in the UART buffer. You can resolve the issue by setting a timeout on the AT+PING command as such:

send_at_cmd_pretty('AT+PING="172.27.131.100",1,32')

With 1 = the amount of messages, and 32 as the timeout in ms (I believe)

That should resolve the error
Best,
Gijs

nadvorvo

Hi @Gijs,
Thank you for your reply.

I have updated my testing code as suggested (also it was necessary add 5 sec sleep (there were interfere with lte.connect() comand):

# Initialize LTE object
lte = LTE()
lte = LTE(debug=True)

print('LTE ping test')
send_at_cmd_pretty('AT+PING="10.1.0.1",1,32', delay=5000)
time.sleep(5)
# Connect LTE
print('LTE connect command:')
lte.connect()

I got this output:

LTE ping test
[AT] 939910 AT+PING="10.1.0.1",1,32
[AT-OK] +9509
Sent to modem: 'AT+PING="10.1.0.1",1,32', delay 5000 ms
LTE connect command:

Could you comment, please [AT] 939910, [AT-OK] +9509 I do not know meaning.
Thank you in advance for your assistance.
Regards, Vojtech

Gijs

Im not sure exactly what you are trying to achieve with the PING (and who you are trying to ping), but a ping to 8.8.8.8 for me gives a response acknowledgement. It seems 10.1.0.1 is in the personal IP range, which might not be directly accessible from the lte service.

nadvorvo

Hi @Gijs,
10.1.0.1 is the address of the NB-IoT backend server ... UDP communication is working there.

I have tried 8.8.8.8 (result is same, My APN network is opened to internet by default, only to backend server)

LTE ping test
[AT] 80166 AT+PING="8.8.8.8",1,32
[AT-OK] +9506
Sent to modem: 'AT+PING="8.8.8.8",1,32', delay 5000 ms

Thank you in advance for your assistance.
Regards, Vojtech

Gijs

This is what I get for an IP that is not reachable: (with lte = LTE(debug=True)

>>> print(lte.send_at_cmd('AT+PING="10.0.1.2",1,32'))
[AT] 2481378 AT+PING="1.2.3.4",1,32
[AT-OK] +9503 

>>>

And this is what I get for an IP that I can reach:

>>> print(lte.send_at_cmd('AT+PING="8.8.8.8",1,32'))
[AT] 2531560 AT+PING="8.8.8.8",1,32
[AT-OK] +1568 
+PING: 1,8.8.8.8,1540,117

OK


+PING: 1,8.8.8.8,1540,117

OK
>>>

Meaning the first one did not get a response (was not reachable), and the second one is reachable, returning the round trip time etc.

Gijs

peterp

@nadvorvo said in T-Mobile NB-IoT in the Netherlands? [SOLVED]:

Could you comment, please [AT] 939910, [AT-OK] +9509 I do not know meaning.

[AT] 939910 means an AT command was submitted at timestamp 939910
[AT-OK] +9509 means an OK response was received after elapsed time 9509

both values are in milliseconds

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T-Mobile NB-IoT in the Netherlands? [SOLVED]

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