Government, industry reach accord on WLANs

The US government and the wireless technology industry have resolved a dispute that threatened to curtail the deployment of the next generation of wireless networking and communications technology that uses the 802.11a standard.

CEO and president of Atheros Communications, Rich Redelfs, said that as part of an agreement reached last week, the government would open 255MHz in the middle of the 5GHz spectrum to unlicensed use, creating 11 additional channels on which 802.11a wireless devices can operate.

Atheros Communications had previously lobbied the government for changes in the spectrum rules.

The dispute between the wireless industry and the government, represented by the Commerce Department’s National Telecommunications and Information Administration (NTIA), arose over concerns voiced by the US Department of Defense (DoD) that devices using the 802.11a standard would interfere with military radars that also use that spectrum.

The NTIA couldn't be reached immediately for comment.

As opposed to devices that use the 802.11b standard and transfer data at up to 11M bps, 802.11a devices can exchange data at faster rates, up to 54M bps, but have a more limited range.

With the rapid adoption of wireless technology that uses the 802.11a standard, especially wireless Ethernet devices, the DOD was concerned that the use of radar in future military operations would be hampered by interference from civilian wireless devices operating in the 5GHz range.

The debate between the NTIA and industry hinged on the use of dynamic frequency selection (DFS) technology that allows 802.11a wireless devices to detect the presence of radar beams on a particular channel in the 5GHz range and automatically switch to a different channel.

The DOD wanted to increase the sensitivity of 802.11a wireless devices that use the DFS technology but the wireless industry was worried that too much sensitivity to radar devices would make their technology unreliable.

With the addition of 11 new, non-interfering channels to 13 existing channels in the 5GHz range, however, there would be more breathing room for both radar and wireless devices that use DFS, reducing the likelihood of conflicts, Redelfs said.

The agreement will also allow the US to present a united front at the upcoming World Radio Conference in Geneva, Switzerland, in June, when representatives from different countries will meet to agree on spectrum allowances and rules.

Without an agreement, the US might have had a tough time getting backing for its own plan, especially because the same 255 MHz band was already open to unlicensed use in Europe, Redelfs said.

Although regulations regarding how the new space in the 5GHz spectrum will be implemented in the US haven't been finalised, Redelfs, whose company makes wireless chipsets and software for wireless networking devices, was confident that change will warrant only minor adjustments.

"We're already shipping products that support (DFS) in Europe. We're confident that with only a software upgrade we will be able to meet the requirement," he said.

To the consumer of wireless technology, the changes - built in to a new generation of wireless access point hardware and software - would be transparent, Redelfs said.

"We think its a great win for the [wireless] industry," he said. "It's a recognition of the importance of the wireless LAN industry and it gives us room to grow. If we don't have enough spectrum and channels, the growth of wireless could all come to a screeching halt -- like a tower of Babel."