Communication errors in LTE


#1

Hello:
I’m using LTE connectivity through Hologram with a SIM7000A modem, and even when I’m able to connect, send and receive TCP data over the network, I 'm still not convinced about the robustness of the communication. Of course, I’m not comparing it to ethernet or even WiFi, but I see communication errors very often, making very difficult to deploy this into a production environment…
I usually get TCP connection timeouts, or SEND FAIL messages, or timeout in send operations. I’m using very high values for timeout in every operation, but so far, there are always some errors in a middle of something making the overall experience very poor… Packet sizes are ~ 400 bytes.

Signal quality is 21 (+CSQ). Not sure if this is a problem with my modem, or environment, etc.

Is there someone really using this cellular data in a real environment (out of a testing environment)? Are you also getting communication errors very often? If so, how do you deal with this?

Thanks in advance.
Gus


#2

Hi Gus,

Is it something that seems to degrade under heavy throughput or over time? At approximately what rate are you sending your ~400-byte packets?

Thanks


#3

Hi:

No, it’s happening at anytime… Sometimes at the very beginning, sometimes after working for some time… It’s random actually, but it happens very often. I would be Ok if errors occur once in a while, and I could deal with them when happen; but my concern is they occur very often.

The rate is perhaps a packet every 5 seconds or so… So this is not the issue.
I created a test of iterate 50 or 100 times a simple tcp connection, sending ~ 50 bytes to a server which echos the data, reading this data back and closing the connection. I would say 6 out of 10, this test does not complete without errors.

Thanks
Gus


#4

BTW, this is not related with Hologram as I also test Aeris and I have same results (at the end, I guess the carriers are the same; AT&T, Verizon, etc).

Would you have a module to recommend? I would like to be sure this is not related with the SIMCOM 7000A module… I’m using an embedded environment, so it should support UART communications with AT commands.

Thanks
Gus