The first system I encountered was a 450 MHz conventional system when I worked for the city of Orlando police department in 1984. It was a standalone police system; the city had a similar system for the fire department and an 800 MHz public-works system. The situation mirrors what I’m doing right now in Houston. It’s really funny; it’s like stepping back in time coming here.
In Orlando, we attempted to do a joint procurement with the county that surrounded the city, but that didn’t really work out because we couldn’t quite come together. Ultimately, we moved in two phases for the city. We moved police and fire onto a new 800 MHz trunked system in 1993. A few years later, we expanded that system and brought public works onto it, so that we had one system for the entire city. And we also were connected to the county’s Motorola SmartZone system at that time.
In Houston, we are building a 700 MHz, trunked P25 Phase II system that everyone will be on. One reason Houston chose P25 was interoperability. The second part is that we don’t really like the proprietary world. We want as much competition as we can get. We want the freedom to be able to buy subscriber units from different manufacturers and — eventually — even base stations from different manufacturers. P25 is the only option for that, unless you want to go back to conventional — but there’s just not enough frequencies for that.
If I were building a system like this five or 10 years from now, I think convergence would be a reality for us. Although a lot of public-safety people won’t like me saying this, I think IP is going to have to come into our world. When that happens, we’re going to see convergence onto IP wireless networks.
I believe that you’re going to see public-safety communications on broadband, if the networks can evolve into being as reliable as land mobile radio. There are challenges to it, but you’ve got people already out there doing demonstration projects to try to address those challenges.
I see our city spending $100-150 million to buy a radio system that integrates voice and data. But the transmission rates are so low that, as the data applications evolve — and they already have — that data rate is not going to be viable for much. If I could spend a third of that money improving my wireless network that I use for all of my other data stuff and make it robust enough to support my land-mobile stuff, why wouldn’t I do that?
I believe the computer world is going wireless, and computer IT departments already are inheriting the land-mobile systems that we have out there. I think you’re going to start hearing them say, “Hey, this is a network and that’s a network. What are the unique capabilities that this has that the other doesn’t. Is there a way to make this other network do that?” They’ll do so because such convergence will make their jobs easier.
I see all kinds of different forces that are going to keep pushing this convergence, and I don’t see how we’re not going to get there. But it’s going to take awhile.
— as told to Donny Jackson
Tom Sorley is the deputy director of radio communications services for the city of Houston.