Clearwire Plans Silicon Valley 'sandbox' WiMax Network

The network will cover the three companies' campuses and the region in between them and will span roughly 20 square miles (52 square kilometers), Clearwire cofounder and Co-Chairman Ben Wolff said in a keynote address at the CTIA Wireless trade show in Las Vegas.

Clearwire plans to reach 120 million U.S. residents with a national WiMax network by the end of next year, but today it has only announced commercial service in two cities. There are only about 30 devices approved to work on that network, though the company expects 100 to be available by year's end. As the first carrier to roll out the new technology on a network of this scale, Clearwire needs to encourage attractive applications for subscribers to use.

Intel has been the biggest single vendor backing WiMax and plans to bring the new system into device chipsets alongside Wi-Fi. Like Intel, Google was a major investor in the creation of the new Clearwire, which was formed last year through the merger of the original startup Clearwire and Sprint Nextel. Google will be delivering online applications as part of Clearwire's service.

But Cisco hasn't been closely associated with Clearwire, though the network equipment giant has gotten into WiMax through its acquisition of Navini Networks in 2007. At that time, the company said it saw the greatest potential for WiMax in the developing world.

Application developers will have free access to the network for at least a year. Wolff did not discuss any public access to the Silicon Valley network. Clearwire has forecast expanding its commercial WiMax service, called Clear, to the San Francisco Bay Area next year.

WiMax is designed to deliver multiple megabits per second to stationary and mobile users. In tests on its Portland, Oregon, network, Clearwire found an average downstream data rate of 6.5Mb per second and at peak rates of 19Mbps in moving vehicles, Wolff said in the keynote. Actual speeds to commercial subscribers can vary based on how carriers divide up coverage.

But the key to mobile competition now is capacity, not speed, Wolff said. A carrier can deliver more speed to fewer subscribers or serve more customers with less bandwidth, but either way, more capacity means a greater ability to offer service, he said.

That attitude fits Clearwire's position as the holder of vast amounts of spectrum, the result of Clearwire and Sprint combining their holdings in the 2.5GHz range. The carrier has an average of 120MHz of spectrum across the U.S. In cities where it has that much capacity, Clearwire theoretically can deliver 540Mbps of peak downlink bandwidth per sector, Wolff said. A provider with 40GHz, the minimum for 4G service, will be able to deliver just 180Mbps, he said. In addition, Clearwire's WiMax provides one-quarter to one-third of the latency of 3G networks.