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Sim7080G module can't send data over TCP while using GNSS

I bought a Simcom (Sim7080G) module to use it for geolocation and send data over TCP. These modules are quite new on the market (it was first launched in mid 2019) and there is some weird functionning with it. I would like to know if people that use it struggle with the same problem.

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My goal is to take GNSS (latitude/longitude) informations, and to send them over TCP.

Activate and take GNSS informations

AT+CGNSPWR=1 returns OK

AT+CGNSINF returns +CGNSINF: 1,1,20200517191239.000,4x.xxxxxx,6.xxxxxx,473.769,0.00,,0,,1.9,2.1,1.0,,7,,7.9,6.0

Connect to any TCP server

AT+CNACT=0,1 returns OK\r\n\r\n+APP PDP: 0,ACTIVE

AT+CAOPEN=0,0,"TCP",151.101.1.69,80 (151.101.1.69 is stackoverflow.com ip address) --> Some time waiting (like +40s) and then: +CAOPEN: 0,23\r\n\r\nOK

The code 23 means: 23 Remote refuse, but in my case the connection never reached the server.

Only GNSS or TCP can be used, but not both

What is weird about all of this, is the fact that I can connect on a TCP server, but this stops to work when I activate GNSS.

Solution

  • I sent an email to Simcom technical support. After insisting that my problem be addressed by a Simcom engineer, I received an answer. I encouraged them to be more clear on their documentation because this information was nowhere (this module is pretty new so I think they missed it on documentation).

    Hope to help somebody in the same way or not to do the same pricey error:

    Hi Dardan,

    "it is not possible to use GNSS and TCP at the same time"

    This is known limitation for this module, as there are limitation for LTE and GNSS part, they can not run simultaneously because they are sharing part of RF components(SIM7070G low cost version of SIM7000G) so it is time MUX for LTE and GNSS which means the GNSS performance could not be good(if customer needs to send GNSS data to server in very short interval such as <10 seconds), for SIM7000G LTE and GNSS can work simultaneously without problem. so SIM7070G could be a good solution for "parcel tracking" etc, which do not need the continue navigation. please go for SIM7000G, thanks.

    xxxx Sun