802.11n

The 802.11n standard brings several improvements to Wi-Fi networking, including faster speeds and new antenna technology implementations.

The 802.11n specification requires all but hand-held devices to use multiple antennae to implement a feature called multiple in/multiple out (MIMO), which enables the devices to make multiple simultaneous connections. With up to four antennae, 802.11n devices can do amazing speeds. (The official standard supports throughput of up to 600 Mbps, although practical implementation drops that down substantially.)

Many 802.11n WAPs employ transmit beamforming, a multiple-antenna technology that helps get rid of dead spots-or at least make them not so bad. The antennae adjust the signal once the WAP discovers a client to optimize the radio signal.

Like 802.11g, 802.11n WAPs can support earlier, slower 802.11b/g devices. The socalled "dual-band" WAPs can run at both 5 GHz and 2.4 GHz simultaneously; some support 802.11a devices as well as 802.11b/g devices. Nice! Table below gives you the 802.11n summary.

NOTE Products that use the 802.16 wireless standard-often called WiMax-are expected on the market any time now. Although speed for 802.16-compliant devices is about the same as 802.11b, manufacturers claim a range of up to 30 miles! This kind of range would be perfect for so-called metropolitan area networks (MANs). Before you get too excited, though, keep in mind that the speed of the network will almost certainly decrease the farther away from the base station (the WAP) the nodes are. Effective range could be as little as three miles.