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What will make or break Wi-Fi?
It’s all reliant on the client, stupid

By Ben King

Published: Tuesday 25 March 2003

Wi-Fi, wireless LAN, AirPort. Call it what you will, the wireless technology officially known as 802.11b is surfing the top of a veritable hype tsunami. Ben King asks what is driving the revolution...

With chip giant Intel splashing £300m on the launch of its new processor-with-Wi-Fi-package, Centrino, you might think that everyone is on the brink of using it.

However, the amount of coverage that Wi-Fi is getting in the press isn’t really matched by the coverage of Wi-Fi networks, and while most computer users get articles about it in their in-boxes, relatively few actually have Wi-Fi cards in their laptops.

If they don’t, it’s not for lack of money. A Wi-Fi card costs less than £60 now, and a base station no more than £90 - less than a year’s 3G subscription or a 3G phone, and certainly less than a mobile base station. But that's another story.

Ease of use is not a great strong point (remember the wireless LAN of constant sorrow) but it hasn’t proved an insurmountable hurdle to business users, who are a large part of target market for mobile data, and generally have access to technical help for the awkward configuration process.

However, 802.11b’s Achilles heel is its greedy power consumption.

Ovum research director Richard Dineen says: “Wi-Fi was designed for use in an office environment where mains power is always available. So it wasn’t designed with power consumption in mind. Wi-Fi consumes orders of magnitude more than a cellular phone.”

For a deskbound user, it’s not a problem – which means that power use is no barrier to the take-up of Wi-Fi for home networks. But for mobile workers, it’s a headache. There’s not much point untying a user from their wired LAN if they’re still tethered by a power cable.

Chip makers AMD, Intel and Transmeta have been responding to this challenge with low-voltage processors for a number of years. Transmeta’s Crusoe was arguably the first but it appeared in relatively few actual production models. But a processor only represents a small part of the power consumption of a typical laptop.

The biggest power drain is the screen and specifically the backlights which power the TFT displays on most modern laptop computers, consuming between 45 to 60 per cent of the power, while the processor consumes between 25 and 30 per cent.

Cutting the voltages and power consumption of processors is therefore only a partial solution to extending battery life.

Intel’s recent launch of Centrino is an attempt to address this. Intel executives have dubbed it the company’s most significant launch since the Pentium and it’s interesting in a number of ways.

Products will only have the right to bear the name Centrino if they combine the Pentium-M processor (previously known to semiconductor buffs as Banias), specific low-power chipsets (855, for those that care) and an Intel Wi-Fi network card.

The Pentium-M extends the power capacities of Intel’s earlier mobile processor, with the confusingly similar name Pentium4-M, by improving its ability to slow itself down when there’s less work to do.

According to Toshiba, which has an acknowledged track record in squashing computers into small packages, the Centrino package of processor and associated chipsets allows for a 15 to 20 per cent extension of battery life on its own.

And here's the kicker: it enables manufacturers to build in other features that save more battery life.

Centrino’s Pentium-M runs at a slower speed than top-of-the-range non-Centrino chips but a 1.6GHz Centrino processor can outperform a 2.5GHz rival by up to 12 per cent, despite the slower clock speed - which has been widely taken by consumers to be the gold standard for measuring their computers’ muscle.

That lower clock speed means lower power consumption, and a smaller, less power-greedy fan to cool it.

As Gary Evans, head of business development at Toshiba UK's computer systems division, explains: “Implementing Centrino, which runs significantly cooler than Pentium4-M, has enabled us to get cleverer on allocation of real estate within the chassis.

“Which in turn enables us to fit a larger capacity battery - 80 per cent more power density but only 30 per cent bigger physically.”

A 1.4GHz Centrino system can therefore reach a quoted battery life of five hours compared to a 2GHz.

Ironically, it’s better batteries rather than cunning chips which will provide the bulk of the added stamina in most of the first-generation Centrino systems – but there’s still a long way to go.

Tony Lock, chief analyst at Bloor Research, says: “Battery technology hasn’t improved as rapidly as processor speed and applications – but fuel cells could be a way to change that.” A fuel cell, instead of storing power like current lithium-ion batteries, generates it by effectively ‘burning’ a liquid fuel like methanol. Current technology can get five hour’s battery life out of 50ml of methanol. The same volume as a double measure in a pub. Future versions could provide even longer life - and a new option for road warriors in desperate need of a drink.

Ultimately improved screen and battery technology could make a larger contribution to achieving what many consider to be the magic battery life figure of eight hours – equal to a transatlantic flight or a day’s work and currently only available with bulky extension packs.

Dumping TFT display technology and replacing it with a system that doesn’t need those juice-guzzling backlights is a key item on every OEM’s agenda. Likewise, improved battery life is a key concern.

Tweaks to the specifications for the 802.11 standards will also reduce the power drain on batteries. Texas Instruments has a Wi-Fi chip that it claims can extend the battery life of a connected PDA by 25 per cent, and reduce the power drain on a laptop by 75 per cent in typical usage scenarios. Longer term, ultra wideband networks offer the possibility of faster network at very low power levels indeed.

However, in the next few years, most peripatetic computer users will find their quest for uninterrupted email access scotched not by lack of battery power but by the fact that there simply isn’t an 802.11b network available.

There are only around 250 hot spots in the UK at the moment, according to one recent estimate. While BT and others have aggressive plans to deploy more, there is still a long way to go before users can be confident of showing up to a hotel or airport and logging on as casually as they might dial a number on their mobile phones.

The launch of Centrino is not just a bid to increase laptop’s battery life. The fact that the Wi-Fi card is included as an essential part of the Centrino marketing package is an attempt to solve the catch-22 situation: With no network, why buy Wi-Fi? And with no users, why deploy a network?

If Intel succeeds in getting Wi-Fi included as standard in most business laptops, the user population will grow almost unawares – and the problem will basically be solved.

The only question remaining will be – who needs 3G?