Please excuse my intrusion to this forum.
I can't comment about the devices currently in use, but I can speculate about where I think they are going. I think 4G technology will be used extensively within 18 months.
The devices/networks will support the convergence of 3G and 4G technologies.
http://grouper.ieee.org/groups/802/16/
http://www.80216news.com/
Just my .02