Successful network connections?

[mbbest]

I am scrolling through a lot of posts relating to difficulties in achieving a connection to LTE Cat-M1 networks. To encourage me to focus on my problem I am keen to know what networks/countries are currently connecting to the FiPy modules via CAT-M1. This will provide me with confidence in the module and encourage me to determine my path to a successful connection. Maybe a table of setups (Firmware, SIM source, Network provider, APN, CID, Antenna, Band, Expansion board/connection to module, etc) to assist others in achieving a connection in the same environment? Should I be able to find this in documentation?

[paulS]

@timh (and anyone else trying to reset)
I'm using nbiot have managed to attach and connect to the vodafone network but seem to be able to get the module in a state that it won't accept any at commands frequently - just returns empty strings to all attempts to talk to it or reset it? Is there any way to avoid a machine.reset()?

lte.send_at_cmd('AT+CSQ')
''
lte.send_at_cmd('AT^RESET')
''
lte.send_at_cmd('AT^RESET')
''
lte.send_at_cmd('AT+CFUN=0')
''
lte.send_at_cmd('AT+CPIN?')
''
machine.reset()
ets Jun 8 2016 00:22:57

rst:0x7 (TG0WDT_SYS_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff8028,len:8
load:0x3fff8030,len:1728
load:0x4009fa00,len:0
load:0x4009fa00,len:14584
entry 0x400a059c
+CSQ: 99,99+CESQ: 99,99,255,255,255,255 <<- modem talking again
False
getting an nbiot connection
attach attempt: 0
OK+CEREG: 5,"2332","024C8C21",7+CEREG: 0OKOKOKOKOK

[timh]

@mbbest One thing to note. I found that if the link goes down, a modem reset is required (AT^RESET).
This allows reconnection, often without machine.reset(). What I also found is even with a machine.reset() a modem reset is required.

[mbbest]

@mbbest Happy to report that with the help of the Pycom Team we have success with attaching to the Telstra CAT-M1 network - Australia. Thanks Daniel, Telstra and other forum contributors for your efforts at working to resolve the issues that had us at a dead end. We are now moving forward and discovering the potential of these modules. Won't bother posting the solution in this thread, as I assume it will be posted in a more relevant topic elsewhere.

[Redferne]

Whoups ;-) Didn't realize that there was a complete overhaul on the Sequans support code. Anyway I changed to DL-EARFCN=1925 and got below result. It still does not register, in fact, there are no operators at all found:

>>> send_at_cmd_pretty('AT+CFUN?')
+CFUN: 1
OK
>>> send_at_cmd_pretty('AT+CPIN?')
+CPIN: READY
OK
>>> send_at_cmd_pretty('AT+CEREG?')
+CEREG: 4,4
OK
>>> send_at_cmd_pretty('AT+COPS=?')
+COPS: ,,(0,1,2,3,4),(0,1,2)
OK
>>> 
>>> send_at_cmd_pretty('AT!="fsm"')
SYSTEM FSM
==========
    +--------------------------+--------------------+
    |            FSM           |        STATE       |
    +--------------------------+--------------------+
    | RRC TOP FSM              |SCANNING            |
    | RRC SEARCH FSM           |WAIT_CELL_ID        |
    | RRC ACTIVE FSM           |NULL                |
    | PMM PLMN FSM             |NORM_WAITCELL       |
    | EMM MAIN FSM             |NULL                |
    | EMM AUTH FSM             |KASME_DEFINED       |
    | 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
>>> send_at_cmd_pretty('AT!="showphy"')
DL SYNCHRO STATISTICS
=====================
    Synchro state                         : CELL SEARCH
    PPU SIB1 ACQ watchdog                 : 2
    Frequency Hypothesis RF  (Hz)         : 0
    RSRP (dBm)                            : -21474836.00
    RSRQ  (dB)                            : 0.00
    Channel estimation state (Cell-spec.) : LOW CINR
    Channel estimation state (UE-spec.)   : LOW CINR
    Channel estimation state (MBSFN)      : LOW CINR
    Channel estimation CINR               : 0.00
    Channel length                        : SHORT
  AGC
    AGC RX gain (dB)                      : 48.31
    RX PSD BO (dBFs)                      : -29.32
    RX PSD (dBm)                          : -112.72
    Noise level RS (dBm)                  : -128.24
    Digital gain (dB)                     : 16.69
    CINR RS (dB)                          : 0.00
  NARROWBANDS
    Last DL NB                            : Central
    Last UL NB                            : 0
  AFC
    Frequency offset RF  (Hz)             : 0
    Frequency offset BB  (Hz)             : 0
  PBCH
    MIB received quantity                 : 620
    MIB timeout quantity                  : 0
OK

[jmarcelino]

@redferne

We expect EARFCN=1575 for band 3.

You can change it if you changes this line and build a custom firmware: https://github.com/pycom/pyupython/blob/master/esp32/mods/modlte.c#L313

[Redferne]

Upgraded GPY to latest firmware, but still cannot get it to register on our inhouse Cat-M1 testnetwork on band 3 (EARFCN=1925). How can I check whether it even finds and tries to register on our network? AT+CEREG? returns 4, which means "unknown".

[jmarcelino]

@mbbest
Some networks like Verizon do require certification, the devices just don't connect if the IMEI is not in the approved list. Most carrier support teams won't tell "home" users this, those details are only know by specific staff members.

There is also some confusion around what "certified" means. Some uncertified devices use modules which have been certified, have the module makers own IMEIs etc so they can connect.

The FiPy however custom built from a chip-on-board solution and using our own IMEIs so there different certification layers involved.

[mbbest]

@jmarcelino
Good to know about APN "changeability". My discussions so far indicated that certification was not a requirement to get operational - but more to guarantee long term compatibility with the network provider, but I'm happy to be better informed.

Have also acquired SIMs that were said to be setup for use on CAT-M1 network, but not sure how that translates to use with the FiPy or Gpy as I assume the necessity to 'enable' the modem. Initially just looking to get a 'TRUE' condition for connection to a cell tower as a first step to an endorphin rush! Once that is achieved we can progress to unicorns and rainbows.

[jmarcelino]

Hi @mbbest,

The FiPy is currently only certified with Verizon US so your experience with other carriers may vary.

Our latest firmware 1.17 is a huge step towards better support and since you can use AT commands you can also specify alternative APNs with:

lte.send_at_cmd('AT+CGDCONT=1,"IP","myAPNhere"')

We've also enabled scanning in more frequency bands.

We are building up more information and will have it up soon.