I think I posted here a few years ago I wondered why a building could not be its own site with just a few channels instead of assuming a half dozen TGs would all be going at once. I can see CBRS being added to LMR like it is being used for carrier neutral DAS in some tests.
Exactly.
I went to a NorCal APCO presentation about a year and a half ago with mostly fire agencies in attendance and this was discussed at length. Most agreed that the current NFPA requirement for radio coverage were pretty awful and poorly thought out. BDA's were greatly discouraged and lots of good examples of their failures were given.
DAS type systems were given as the superior choice.
I brought up LTE/WiFi and got a few nods, but most seemed stuck on the idea that the LMR specific DAS system was the solution.
The downside of using a 3rd party network is the lack of control of all the devices accessing it and we are at the mercy of the network operator to respond as quickly as we do.
Yeah, that's the challenge to overcome. My experience with network wonks and emergency type services has not been without challenges.
Not an insurmountable task to overcome, but not going to be easy.
Most of this has already been solved, though, on some scale. The EduRoam system provides authentication for roaming users between many large educational institutions where devices will automatically register when it finds an eduroam network. Something similar could be set up for public safety users.
Getting building owners/LAN operators to agree would be a challenge, but probably no harder than getting those same people to actually maintain their BDA systems.