An antenna-based alternative

A different approach to beamforming, sometimes called beam-steering, is used by some vendors, such as .  It's based on an antenna design that uses multiple components, each of which can be turned on separately, to create an array of focused energy patterns, as many as 4,000 for Ruckus access points. Software then analyzes these signal patterns and selects the one that offers the best throughput. The Ruckus access points do this continuously, for each packet with each client, says Bill Kish, Ruckus co-founder and CTO.

Kish says that such active antenna systems are more successful in rejecting radio interference than the conventional omni-directional antennas of rival access points, and there is no upper limit on the gain that can be created. He says the Ruckus products can deliver gain improvements of 5-20 bBi.

A Cisco on this distinction stresses the efficiency of chip-level technology, says that active antenna systems are "suboptimal when clients are moving," and they suffer from the drawback of being one-way only -- they improve the downlink but not the uplink performance.

Toyota's Parker likes Cisco's silicon-based approach, precisely because it does leverage continued chip improvements without impacting performance, as well as because it leverages Cisco Compatible Extensions (CCX). CCX is code that runs on client Wi-Fi adapters and integrates them tightly with the Cisco WLAN. "With CCX, they have more knowledge of and control over the [Wi-Fi] client," Parker says.