"The main problem [in high density deployments] is radio congestion -- the RF gets saturated," says Kish. "The spectrum is highly utilized at a fairly high power level. So there are very few 'windows' for a client to jump onto the RF link. You have to give as good a link as possible to each client, so they can get on and off quickly."

If links degrade, Wi-Fi access points automatically drop down to lower data rates to improve link quality. But that change slows the network down for all clients.

The Ruckus access points in the arena run in both the 2.4GHz and 5GHz bands. In an unusual move, the WLAN uses all 11 available 2.4GHz channels, instead of the conventional three non-overlapping channels. The reason is the way in which the 802.11 standard handles the initial signaling -- it uses a preamble to start each 802.11 transmission. The preamble is sort of like yelling at the top of your voice in a crowded room to get someone's attention, according to Kish. But this low-energy yell can be heard by a lot of access points, and when they hear it, they drop what they're doing and try to focus on the receiving process for this "shout," according to Kish.

"You want to avoid this [reaction] in a high-density environment," he says. "If someone is transmitting at a low level, you want the access points to 'not hear' that transmission," he says. "Staggering these [11] channels is one way to accomplish this." The new, narrow-sector antenna aids in this.

This additional spectrum reuse in the 2.4 band is important, says Kish, because "we're seeing now only about 10% of the Wi-Fi clients supporting 5GHz." Ruckus' built-in "band-steering" can direct clients that do support 5GHz to connect on that frequency.