We called him crazy, but he just kept coming at us: Peter Judge writes about Extricom, the company that produced a barrage of what appeared to be overblown throughput claims last November, but now offers enough details to evaluate their technology. Their claims of huge throughput weren't across the entire system--that is, 1 Gbps everywhere--but rather aggregated throughput from multiple cells on the same network using the same channels.
The system promotes channel reuse by leveraging the collision detection that's at the heart of 802.11 and Ethernet systems to better use the empty spaces that are wasted in routine Wi-Fi communication. Each Extricom switch has multiple thin APs on the same channel. The switch decides which AP handles which client without switching channels, and thus the client doesn't change its connection (which means handoff latency is reduced far below any conventional system) and the switch maximizes the use of the RF space.
APs are coordinated at the switch level to avoid interference, but the 802.11 specification can handle co-channel interference as well. Between those two parts, the amount of interference is dramatically reduced. The goal is to allow many simultaneous voice conversations by bringing each client's available bandwidth as close to the maximum throughput for their particular standard.
The only complaint from a test site seems to be the current eight-AP limit on their first switch model. That model will ship in May for $8,000 to $14,000 based on quantity and options like Power over Ethernet, according to the Techworld report. A 32-port switch will follow in the fall.
It's ingenious, and I've confirmed that this could work (if implemented properly) with a Wi-Fi expert. It's too bad they didn't explain this more clearly six months ago.