Start-up testing auto-aiming antenna for wireless nets

Purdue profs say technology could improve mobile access to 'Net.

WEST LAFAYETTE, IND. — A group of Purdue University professors has launched a start-up to create an auto-aiming wireless antenna system that reliably links users on vehicles and boats to the Internet.

The start-up, called Broadband Antenna Tracking Solutions (BATS), uses proprietary software and off-the-shelf electronic components that let one antenna find, lock onto and track another, even when one of them is in motion.

The system lets a seeker antenna find a target one quickly, and then constantly adjusts the seeker's position to optimize signal strength and throughput. Because BATS uses directional antennas, which focus a radio signal into a narrow beam, the connection can be maintained over longer distances and is less vulnerable to interference. Tests with the current BATS prototypes have reached nearly 12 miles over water and nearly 9 miles over land.

The system is designed for 802.11 (Wi-Fi) and fixed wireless broadband radios, such as Motorola's Canopy product. In the future, WiMAX will be supported, says Lonnie Bentley, vice president with the company.

That's also the home of Purdue, where Bentley heads the university's Computer & Information Technology department. With development seed money from the university, he and two colleagues and co-founders — Anthony Smith, who did much of the work on the algorithms, and Michael Kane — developed the antenna aiming system.

The patent belongs to Purdue, but the trio negotiated exclusive global licensing rights to the technology, put up their own money, convinced former Nextel executive Phil Hockema to join as CEO, and launched the company in January. "Our CEO is doing it for free so far," Bentley says. The company is seeking investors.

Getting wireless antennas of all kinds to find each other isn't easy, according to Bentley, especially in outdoor networks, and where either the user or the access point or base station is moving. Installers working for wireless service providers, for example, may spend frustrating hours trying to align the antenna at a customer site with a base station miles away.

The BATS solution comprises three main elements. One or more off-the-shelf directional antenna is packaged with the relevant radio or access point and two standard servo motors that can tilt and swivel the antenna. The motors are managed by a programmable logic controller (PLC), which in the BATS prototypes is a separate box but in the final product will likely be a small board incorporated in the antenna-radio-motors package.

The heart of the system is a laptop software program that reads the signal strength of a target antenna and then calculates the optimal position for the seeker antenna. The program passes instructions via the PLC to the servos, which move the seeker into position. If both ends of the link are stationary, the software can lock that position. If one end is mobile, the software continually tracks the target antenna and adjusts the seeker's position as needed.

The prototypes have been tested using the 900-MHz Motorola Canopy radios, a popular wireless broadband product. In one test, the BATS system linked a moving U.S. Coast Guard boat about 10 miles offshore in Lake Michigan with a stationary radio ashore. Another test involved the BATS antenna mounted atop a moving Chevrolet Tahoe, connecting to a radio on a rooftop, at distances up to 8 miles, according to Bentley.

"We lost the signal in [dense] forests or valleys, but it re-established as soon as we had line of sight," he says. Bentley says the initial tests indicate the system could connect antennas up to 20 miles apart, depending on which radio technology is being used.

The system can be used to quickly link vehicles or ships together or to distant fixed wireless base stations, as well as pilotless drones to attack helicopters in flight. It can be used in mobile or fixed wireless networks or a combination, according to Bentley. Sensors mounted on farm tractors can use BATS to transmit data using Wi-Fi or fixed wireless radios instead of expensive and limited satellite links.

The final product will likely be a black box with the electronics, able to support wired and wireless links to a laptop or other local client, and customer-selectable radio-antenna combinations in various types of housings.

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