Print
Discuss
Send to friend
RSS feedsIf as expected the UK Radiocommunications Agency (RA) this week relaxes restrictions on commercial use of the 5GHz radio frequency waveband, faster 54Mbit/s 802.11a wireless LAN equipment will become more cost-effective and easier for IT managers to implement.
Currently, organisations wanting to use 802.11a kit required a licence from the RA. These licences cost £300 for six months and could take up to six weeks to acquire. It is anticipated that this licence requirement will now be scrapped.
However, concerns about signal interference with government and military communications mean the RA will only allow companies to transmit data in the 5.15GHz to 5.25GHz part of the radio frequency waveband, leaving the 5.25GHz to 5.35GHz free for other traffic. This limit of only four 20MHz channels restricts the range and number of users that can be supported by each 802.11a-based WLAN. Even so, compared with 802.11b systems, 802.11a promises faster transmission speeds and less risk of signal interference.
Michael Wall of analyst firm Frost & Sullivan agreed that allowing use of only four channels would limit the range and scalability of 802.11a WLANs: "When you have eight channels (as in the US), you can have eight access points all configured to a different channel. That gives a much greater coverage area because none of them overlap. Having only four channels significantly reduces the area of network coverage."
Dominant platform
Initial demand for 802.11a equipment is likely to be low. Most firms are content with proven 802.11b equipment already widely available. Ian Philips, product marketing manager at Cisco Aironet solutions, said, "There is some pent-up demand (for 802.11a) at the moment, but I think that 802.11b will continue to be the dominant WLAN platform for another 18 months."
Wall agreed, "I don't think there will be a major demand for 802.11a equipment at this moment." But he added that a small number of firms would use 802.11a kit to support high-bandwidth applications, including some companies that will want to channel voice and video traffic over the WLAN.
"There are certain bandwidth-hungry applications in the financial services market, for example, that may need the faster transmission speeds," he said.
Cisco will begin shipping its 802.11a-compatible Aironet 1200 series access point upgrade to UK customers next month, although it will be up to customers to configure the equipment so it does not use the transmission channels prohibited by the RA.
The Institute of Electronic and Electrical Engineers is working on a draft 802.11h WLAN specification, which will add the ability to switch data signals from one transmission channel to another when interference is encountered. The inclusion of this dynamic frequency selection (DFS) feature in 802.11a equipment should overcome the RA's objection to use of the 5.25GHz to 5.35GHz part of the waveband.
Have your say: contact IT Week
del.icio.us
Digg this
reddit!
