best LTE modem for diagnostics?


#1

Does anyone have a recommendation for the best LTE-capable modem for diagnostic purposes? What I mean by that is a modem that has a well documented AT command set with commands to find out as much as possible about available carriers, available towers, etc.
I’m using an old Sierra Wireless 313U and it provides the typical rssi, rsrp, rsrq, snr for the current connection but I can’t find any command that would give me info on other available towers (at least not for LTE). Also there is no info on which data rate it’s using, retransmission rates or anything. I’m interested both in high data rate modems as well as Cat-M1.
I see that in the Sara-R410M the +UCGED command has up/down bandwidths.
The R404M has a couple of +VZWxxx commands that appear to retrieve info about multiple cells, but that command doesn’t seem to be available in the R410M…
Is this the best there is?


#2

I would say the line from U-Blox is probably your best bet and you found one of the commands you’ll need (+UCGED) although note not all modes are supported (only mode 0 and 5 per Table 4, the two with the least amount of information). You may also use +COPS=? and +CESQ to get some relevant information although you need to be connected to a tower for some of these to work.

At the end of the day I think what you really want is an LTE Scanner, or similar piece of test equipment, not a modem. I think modems just dont need that functionality so dont include it. What I think you want is an LTE Scanner something like: https://www.amazon.com/SureCall-Five-Band-Cellular-Installation-SC-METER-01/dp/B00EFL0OWE Or a spectrum analyzer with an LTE option that parses out the tower information (these will likely be $2k-$50k depending). There are also some open source project making LTE scanners based on software defined radios.

My suggestion would be to look at the amazon link and others like it as an economical way to get what you are looking for. These handheld things aren’t that cheap for a hobbyist but if you account for the time it would take you to make a less capable version on your own based on an LTE module then $200-$500 seems cheap, atleast to me.


#3

Thanks for the thoughtful response. I completely forgot about LTE-Cell-Scanner using an RTL-SDR! I think I’ll start there to do a survey.