Gordon Laing

Wireless networking is one of today's fastest growing technologies and some of its supporters believe sales could soon even equal big consumer brands.

As with so many things in life though, increased popularity can lead to saturation and subsequent disappointment.

Congestion is the hot issue right now, and there can be few potential buyers who haven't heard the most common wireless networks share the same frequency as Bluetooth, cordless phones, wireless video senders and even microwave ovens. But what does this actually mean?

Well, I've got a cordless Dect phone and an 802.11b wireless network in my home, and I've never measured one having any impact on the other.

Of course this might be different if you were in a call centre with hundreds of cordless phones, or surrounded by neighbours with wireless video senders, but I'm guessing the vast majority of homes don't lose too much sleep about this.

Where congestion potentially becomes a serious issue though is when other wireless networks are nearby. The biggest shock for anyone setting up their first wireless network is realising they're not alone.

When I fired up my first wireless network, I was surprised to discover two others within close range. Nearby neighbours had beaten me to it and now the three of us were potentially conflicting.

Wireless networks can co-exist without interference, so long as they're running on channels set at least two or three apart.

But in such ideal circumstances, the 802.11b standard would only accommodate three or four wireless networks in nearby proximity, and you also might have to ask your neighbours to change their channels.

That's why a site survey is crucial when setting up a new wireless network. This essentially searches for nearby wireless networks and reveals what channels they use, allowing you to keep well out of their way.

Such surveying utilities are commonly supplied with wireless access points, or check out Netstumbler at www.netstumbler.com.

But you may have to prepare for the worst. One professional installer recently told me how he had to explain why a new client's wireless network in a shop on a busy London street was performing so badly.

One site survey later countless wireless networks within range were revealed, many using conflicting channels and affecting each other's performance.

Potential congestion is also one of the biggest arguments against the forthcoming 802.11g standard. This is being sold on higher speeds and backward compatibility with existing 802.11b networks, but by using the same 2.4GHz frequency, you've still got the same congestion issues.

It's also worth pointing out that building a new 802.11g network doesn't guarantee faster speeds. In tests with early products using the draft specification, we found that connecting just one 802.11b device to an 802.11g network reduced the performance of all devices to 802.11b speeds.

802.11g may be a cunning technology, but for the best results don't connect any 802.11b devices simultaneously.

The only solution to 2.4GHz congestion (beyond considerate installations) is to move to a different frequency altogether. This is what 802.11a offers by operating at 5GHz. This higher frequency also results in a lower range, which reduces the chance of conflicting with neighbouring networks.

That said, unless every home wants wireless networks, most users should still be fine using either 802.11b or 802.11g. Anyone in built-up areas with potential congestion, though, should consider 802.11a.

As wireless networks evolve we're likely to see more dual-band products, supporting all standards. This is important, as anyone adopting 802.11a will still want 802.11b compatibility to use the number of public hotspots springing up globally.

Which leads me to a personal rant: why are public hotspots so expensive?

BT charges £6 per hour or £15 for 24 hours of wireless access at its Openzone hotspots. This targets it at business use, yet I'll bet I'm not the only consumer with a Wi-Fi-enabled notebook or PDA who fancies checking their personal email wherever they may be.

The problem is wireless hotspots are being marketed by many as a superior and expensive business service. Surely wireless hotspots should be cheaper than cyber cafes, as the proprietor doesn't have to fit cables, provide computers, or worry about powering, insuring and maintaining them?

Many hotels now offer wireless access at roughly twice the price many business travellers pay for broadband through a wired Ethernet port. So why are we paying extra for something that costs less to deploy?

Maybe I'm naive, but I had hoped some establishments would offer wireless access for free to encourage custom, securing it to ensure only genuine customers got the benefit.

Wireless networking may be a wonderful technology, but I just hope responsible installations prevent congestion from becoming a long-term issue, and that public hotspots don't alienate a growing market by sheer greed.

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