Cognitive radio hits the fast track

For the military, the ability to communicate in hostile environments is paramount in order to achieve missions and to minimize fatalities and damage to critical assets. In many cases, spectrum usage cannot be assured, and signal jamming in a battleground scenario is an accepted practice.

With this in mind, the Defense Advanced Research Projects Agency (DARPA) has been developing dynamic spectrum-access technologies that would allow military forces to utilize whatever airwaves are available in a geographic region on a split-second notice, which would greatly decrease the need for spectrum planning as troops make advances.

This capability has been a hallmark of DARPA's Wireless Network after Next (WNaN) project, which is being sponsored by the U.S. Army to provide personnel with integrated voice and data information. This system also features ad-hoc networking between the cognitive radios with sub-100-millisecond latency, so the network can operate without traditional infrastructure.

Because the WNaN cognitive radios are able to access the best available spectrum at a moment's notice, the devices do not have to include expensive components designed to overcome interfering traffic, which is how the Army plans for these radios to cost less than $500 per unit when built in quantities of 100,000 or more.

Last year, DARPA successfully conducted a 10-node test of the WNaN technology, which also demonstrated disruption-tolerant networking technology that is designed to ensure that no packets are lost during data transmission. This year, DARPA expanded its WNaN testing by conducting a 52-node demonstration in the summer and a 100-node demonstration in the fall.

To date, the military has declined to release the results of this year's WNaN tests, but DARPA last month began soliciting proposals for a $22 million project called Advanced Wireless Networks for the Soldier (AWNS) that “will use the cost-effective radio developed under the WNaN program as the base platform,” the agency said in a press announcement.

In the announcement, DARPA emphasizes its desire to leverage commercial technology in AWNS to give soldiers access to mission-critical information at all times and to help ensure that the system can integrate the latest communications capabilities in the future.

“AWNS communication systems adapt to changing conditions and mission requirements by adjusting frequency, modulation scheme, operating power, and topology of the network, particularly at the physical and link layers, to create and maintain a rich, multiply-connected network fabric,” the announcement states. “This rich interconnection provides superior battlefield communications at lower system cost and enhances survivability by ensuring information, applications, and services are readily available.”

Continuing its theme of leveraging commercial technologies, the Army reportedly will begin testing secure cellular technology from Sirran Communications by the end of the year. Early next year, the Army will test the commercial cognitive-radio solution from xG Technology in the field at Fort Bliss and in the lab at Fort Monmouth.

Historically, many wireless technologies — particularly those used for mission-critical public safety and enterprise applications — have been developed initially for military use. With military officials actively seeking technologies that can be adapted for domestic use — increasing the size of the potential market, which could lessen per-unit costs — many industry observers believe the transition time from military application to domestic usage for cognitive radio could be shorter than it has been for previous technologies.

— Donny Jackson