Just when we thought the wireless LAN industry was in shake-out mode, with all the existing players due to be bought up, a new startup has popped out of "stealth mode", claiming to have packed a whole WLAN system in one unit, that has better capacity and coverage than the competition, and planning to bring the products to Europe this Autumn.

Xirrus uses directional antennas to put sixteen non-interfering access points in one box, along with a Wi-Fi switch. This allow more users to connect, and minimises installation. The idea is somewhat similar to the directional approach of Vivato, although it does not steer the radio beam.

"Xirrus is currently going through the certification process of our family of WLAN Arrays for sale into Europe," said John DiGiovanni, director of marketing at Xirrus. "We do not anticipate any regulatory issues that would prevent Xirrus from selling our products outside of the United States and plan to roll out our products in Europe in the third quarter this year."

The Xirrus XS-3900 Wireless LAN Array combines up to 16 802.11a radios, smart antennas and a WLAN switch in a package that looks like an oversized smoke detector. Xirrus software coordinates the 16 WLAN radios, boosting capacity by giving users sixteen separate 54Mbit/s channels, compared with just one channel on a conventional, one-radio access point.

The effect is like taping together 16 802.11a access points, but adding a special multi-sector antenna that directs the radio energy, thereby extending its range, and adding software to block interference between the radios so users can use adjacent channels without interference.

One of the 3900 arrays is being used to cover a two-story, 7,800 square foot classroom building on the campus of the Viewpoint School, an independent primary school in California. The single array mounted centrally on the second floor ceiling handles coverage for the entire building and extends the WLAN roughly 150 feet outside the building, says Paul Rosenbaum, the school's director of technology.

Previously, the building had four Cisco Aironet access points to cover the same area with adequate performance.

Rosenbaum is considering the array for a new 40,000 square foot building under construction, because the Xirrus products will reduce WLAN installation and maintenance costs. "Lots of client devices can associate with one [Xirrus] device. That's a huge plus," he said. Using the Xirrus DC power option will eliminate the need to install AC power lines to each array.

The array comes in four, eight and 16-radio models, looking somewhat like an 18-inch dinner plate with the radios mounted around the diameter. The array can have up to 12 802.11a radios and up to four dual-frequency radios, which can support either 802.11a or 11b/g clients.

Each radio has a sectorised antenna, which in effect, concentrates the radio's energy in a specific sector, instead of letting it radiate in all directions as in a conventional access point. By concentrating the energy, the array extends the radio's range, so that at any given distance, the available WLAN throughput is higher than with a conventional device. Xirrus executives say that the typical range for an 802.11a access point is less than 100 feet, but the Xirrus array can reach 175 to 200 feet. The company says the array has about twice the range, at any given data rate, of rival access points from Cisco/Airespace, Aruba and Trapeze.

One radio can be designated as a radio monitor, constantly sweeping the airwaves to check signal strength and detect unauthorised WLAN signals.

The built-in WLAN switch, which Xirrus calls an array controller, carries Xirrus software that creates a media access control layer that spans all the radios, instead of each radio having its own MAC address as in conventional access points. In effect, the Xirrus software creates one radio with 16 channels, all of which can operate at the same time.

The switch has two Gigabit Ethernet uplinks to connect upstream to the nearest wiring closet switch. It is powered by an 800MHz PowerPC with 640MB of RAM.

The products will ship in the US in May, costing $4,000 for the four-radio 3500 model, $7,000 for the eight-radio 3700 array, and $12,000 for the 16-radio 3900 array. The management models range from $5,000 to $25,000, depending on the number of arrays being controlled. The remote power system starts at $2,000 for the chassis and one expansion module, which powers four arrays.