Based on the press release Cory linked to, they support up to 150 "simultaneous" users moving within a 100-degree field of view. The beams are 9 degrees wide, and it sounds like they can only have 3 beams going at any one instant.

I understand how this works to transmit - when you get a packet from upstream destined for user X, pick a free beam (or wait for one to become free), point the beam at the area where X was last, squirt out the packet, and listen for the ACK, then move on to the next packet/user. But how do they handle receiving from the users? Do they steer the beams rapidly to each user fast enough that when user Y starts to transmit, they're guaranteed not to miss it? Sort of "glancing" at each user very rapidly, looking for activity?

Also, how do they "track" moving users? Do they wiggle the beam, and see which side has better signal strength? It sounds like they also periodically scan the whole area, looking for new users, so that would provide a back-up if they "lose" a user. Or maybe they just rely on scanning for activity, and don't really "track" users' locations over time.

http://www.quicktopic.com/boing/H/JHd5YfvBUZqrn

"So I'd say $10k for the initial introduction. Others will probably be able to provide a more refined guess."

From discussions with wireless experts, it sounds like the price won't be coming down too much. Most of the cost in a wireless radio is in the RF amplifier circuitry, and an array has a lot of those.