The 802.11a standard has failed, according to some wireless LAN (WLAN) vendors, and it will take the implementation of the IEEE's proposed 108Mbit/s 802.11n specification to persuade both WLAN equipment makers and users to invest in kit that transmits data in the 5GHz radio frequency waveband.

"I think 802.11a is just about dead," said Michael Wagner, worldwide marketing director for Linksys, a division of Cisco that currently manufactures and sells a mix of 802.11b, 802.11g and 802.11a equipment. "Less than five percent of our sales are 802.11a and it has not increased in the last two years. [But] I think 802.11n will re-ignite interest in the 5GHz spectrum."

Originally touted as a replacement for the 11Mbit/s 802.11b standard, 802.11a offers more bandwidth - up to 54Mbit/s - in the little used 5GHz radio frequency waveband, which is less likely to suffer interference or signal congestion from other equipment, such as Bluetooth-enabled devices.

This also means 802.11a kit is not backwards compatible with firms' older 802.11b equipment, which transmits in the 2.4GHz waveband, so 802.11b clients cannot connect to 802.11a access points and vice versa. In contrast, 802.11g, which offers the same maximum 54Mbit/s bandwidth as 802.11a but uses the 2.4GHz waveband, is backwards compatible and has become more popular with buyers as a result.

Andy Greenhalgh, director of marketing for Intel mobile wireless, pointed out that congestion in the 2.4GHz waveband is set to become even more of an issue if analysts' predictions about increased sales of 802.11b/g wireless equipment are accurate.

"Writing 802.11a off today is little premature," said Greenhalgh. "As more WLAN devices come onto market over the next two years, we will see more dense, complex 2.4GHz wireless environments that force 802.11g equipment to drop back to 802.11b bit rates." He argued that this would cause some organisations to implement 802.11a wireless LANs.

The proposed 802.11n specification, currently being defined by an IEEE working group, is not expected to be ratified before the end of 2006, and decisions regarding its waveband usage and bandwidth have yet to be made.

Some hardware vendors may release pre-standard equipment in mid-2006, but this leaves a window of opportunity for increased sales of 802.11a devices in the meantime, said Greenhalgh.

Linksys's Wagner also cast doubt on the performance of 802.11a equipment, criticising its low range and reduced throughput when used within buildings. "The biggest problem with 802.11a is that it does not go through walls," he commented.

Greenhalgh conceded 802.11a data rates are affected by walls and ceilings, and vary from site to site. "That's the reality of the 802.11a standard. The throughput you get is the throughput you get," he said