I work for a IOT company that uses nothing but LTE signals for device position acquisition. FWIW, cheaper, less POWER, and the device can report its position with the LTE modem. One of the things I am helping with is working with the modem vendors we are partnered with testing the devices. I've been able to find crashdumps and lockups in one of the vendors modems. They are getting close to finishing up their next release of firmware.
Not nearly as fun, had to take the truck, had my laptop and a fairly high precision current/power measurement box for a drive out of the urban environment. Creating a model for power consumption. Too hard to find a poor cell area in the city. And sometimes it is much easier to go for a 4 hour drive in the country than try to set up a test environment. But I am starting to get them convinced, I think, to purchase a desktop RF Anechoic Chamber.