Communication is the most “magical” of an AVL system’s components– it carries information over the ether from vehicle to server, and when it works, it just works. It is also the most well understood of these components, so this post will focus solely on things to watch out for.
Cellular:
Most AVL systems are now using cellular communications. Hardware is easy to acquire, costs are somewhat reasonable, and speeds are more than enough for low bandwidth applications.
One thing to watch out for is the the “sunsetting” of 2G and 3G networks. In the US, wireless carriers will be shutting down 2G and 3G networks as soon as 2016 (AT&T), and possibly as late as 2020-21 (Verizon). At this point, solutions that provide no upgrade path to 4G should not be considered for the long run.
Private/Packet Radio:
Packet radio is what has traditionally powered AVL communication. Older AVL-over-radio systems suffer from very long update intervals– often 5-10 minutes between position updates. Most new systems have much shorter intervals, but it is crucial that you know what the update interval is, regardless of technology or age. Some unscrupulous vendors are still selling systems of a previous generation.
Mesh
Long touted as the next big thing, mesh networking has never taken off commercially. The industry has not given up hope =iIt is still seeing new research. Be wary if it is proposed; the supplier better have a good testing and backup plan.