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Changing WiFi physics: Vivato's "antenna for every packet" switch

What is a WiFi switch? We'll find out this quarter, when startup company, Vivato stops doing wireless networking by broadcasting all packets continuously in all directions, and instead, offers a new technology which beams each Ethernet packet directly, in a tight beam, towards each client network node. And it will work on most versions of 802.11 wireless, they promise. However, exciting though it promises to be, it may well be illegal in the UK.

Vivato has announced that it will deliver "a complete family of innovative Wi-Fi infrastructure products" - featuring what it has called WiFi switches, for both indoor and outdoor use. They'll operate in the licence-exempt 2.4 GHz and 5 GHz bands, used by 802.11a, 11b and 11g standards.

The secret of the technology is described as a "planar phased array antenna" - which creates highly directed, narrow beams of WiFi transmissions. The WiFi beams are created on a packet-by-packet basis. Vivato calls this technology PacketSteering.

This beam is effectively a high-gain antenna that is formed for the duration of a packet transmission. The result is extreme range - extending the reach of Wi-Fi from tens of meters to kilometers. Indoors, the company says, it allows them to send this tight beam across the whole area of an office floor. Out of doors, it can reach up to seven kilometers.

This is likely to be the cause of some delay in getting the technology approved for use in the UK (and some European countries). There are strict limitations on the intensity of signal which is permissible under UK 2.4 GHz regulations; and a tightly-focused beam - however it is produced - can breach these regulations.

In the past, however, this sort of problem has arisen - and been overcome - by a protocol of transmit power control (TPC). For example, the first 802.11a specifications were rejected in Europe - for political reasons! - and the pretext was that they were unable to limit transmit power. The new 802.11a specification was drawn up to make TPC required - which had, of course, the side-effect of making 11a far more efficient at close range for battery-powered units. There's no obvious reason to suppose that Vivato can't design TPC restrictions into its switches.

Vivato claims that its network switches are changing the "physics" and economics of wireless LANs, because it will be possible to cover large areas with single switches, where conventional designs would require several access points.

Indoor switches are designed to be installed in the corner of a building and provide coverage for an entire floor. "One manageable network element, instead of many, controls the entire Wi-Fi network."

The most efficient way to provide WLAN coverage for an entire building is from the outside. "A single Vivato switch can provide wireless coverage for a multiple story building when placed on an adjacent building, an ideal solution for campus deployments of WiFi."

The company's press release goes on to assure prospective customers that its switches "are built on industry standards and are designed to be flexible enough to seamlessly integrate into the existing management framework of enterprise customers." Normally, this phrase needs careful reading; "built on" is not the same as "conform to" and usually implies non-standard extensions; in this case, they look pretty obvious.

One area where there may well be innovations, is in security, which the company has extended beyond the standard Wired Equivalency Protocol (WEP) and Temporal Key Integrity Protocol (TKIP) with 802.1X authentication with per station keys. It also includes higher-level security mechanisms normally found in add-on products such as Virtual Private Networks (VPNs) and Virtual LANs (VLANS) built into each switch.

Vivato also is introducing Rogue AP detection with its switches. This allows a network administrator to discover and pin-point any wireless access point which individual staff may have attached to the wired Ethernet for the enterprise.

It would be easy enough for the system to discover other wireless systems, because of the highly directional nature of the switch phased array antenna. Whether this will be an accurate way of pin-pointing them, remains to be seen; reflections of a signal could make it confusing in many offices.

Vivato's initial product introduction is expected in the first quarter of 2003.

Vivato is the inventor and first manufacturer of Wi-Fi switches for enterprises and service providers designed to enable high bandwidth Wi-Fi wireless networks everywhere: in the enterprise, across campuses and throughout metropolitan areas. Vivato is headquartered in San Francisco with a research and development center in Spokane, Washington State. For more information, please visit the Vivato web site; or call +1 415 495 1111.