USB without wires

It’s not that long since hooking up peripherals to computer was a fraught affair. Connectors were physically cumbersome, attaching devices meant shutting everything down, and data transfer rates were slow. Seasoned computer users will remember the serial and parallel ports required to connect modems, scanners, printers and the like.

Times change and we now have the universal serial bus (USB) by which bandwidth-hungry hard drives, analog-to-digital audio converters, video cameras and more can shunt their data back and forth with hardly a glitch. Aside from USB’s high connection speed, currently a maximum 480Mbps (megabits per second), a major bonus is that a USB device is ‘hot swappable’, in that it can be connected and disconnected without having to power down the computer.

Today’s operating systems will recognise the peripheral, request the driver disc if necessary (which it usually isn’t) and start communicating within moments. The bus can also supply power to such peripherals as mice and keyboards - in fact, with the appropriate cable, you can use USB to charge the cell in your mobile phone or digital camera. So successful is the technology that industry analysts reckon there’ll be five billion USB-equipped devices worldwide by 2008.

It’s not all roses, however. For all USB’s convenience, peripherals still have to be connected with wires and the specification supports a maximum cable length of five metres for high-powered devices; 3m for low-powered. It’s to do with the way the cable handles electromagnetic fields, although chaining hubs together can extend the range to a maximum 30 metres. But wires are not the way forward. Various companies are working on methods of transmitting USB data streams via short-range radio signals. One such developer is Alereon Inc (www.alereon.com), a provider of ultra-wideband (UWB) technology for mobile computing.

Alereon director Mike Krell says: “Wireless USB is a cable-replacement technology for personal area networks. It is meant to replace USB cables out to approximately 10 metres.” The aim is to create a system that behaves exactly like USB, but without wires. And UWB could take transfer rates way beyond those of USB 2.0 - up to 1Gbps (gigabits per second), and without hammering the batteries of portable devices. “UWB is the most power-efficient wireless technology available today,” says Krell. “We measure our effectiveness in gigabytes transferred per AA battery. We are at least 10 times more power efficient than Wi-Fi and at least 50 times Bluetooth. This allows us to provide the convenience of wireless without draining a battery.”

Anyone with a Wi-Fi or Bluetooth-equipped mobile phone or laptop will attest to the power-hungry nature of radio-based data transfer, and those using Bluetooth will be aware of how slow it can be. Current Wi-Fi technology (labelled 802.11g, as you’ll see printed on the packaging of consumer-orientated wireless products) takes the ceiling to 54Mbps and this looks set to increase by a factor of 10 with the next-generation 802.11n. Whenever, that is, the alliance developing the technology gets around to finalising the standard, which is unlikely to happen before 2008. Krell sees wireless USB turning up a little sooner.

“The initial products will be in typical add-on form factors such as Cardbus cards, ExpressCard/34 cards and USB adapters, along with wireless hubs. Mid-year [2007] you will start to see laptops with this technology built in. Typical PC applications will include wireless disk drives for backup storage and printers, while in the handheld market you will see digital still cameras, mobile phones, MP3 players and personal medial players, all with this technology built in.”

Naturally, for we consumers, there’s the issue of cost to consider, but industry pundits do not predict huge prices in the longer term. “Like any new technology, it will start in the higher end devices then migrate to the lower end,” predicts Krell. “For example, you will see smart phones and PDAs with the technology integrated first, then lower end phones. Over time, wireless USB costs no more to add to a device than Wi-Fi.”

It’s as yet unclear when we’ll be able to get our hands on the first generation of wireless USB devices. Various peripherals, including hubs and hard drives, have been displayed at conferences and shows in the past year, but there’s nothing available to buy just yet. As has happened in many fields of technology, different manufacturers have been working on different solutions and there’s still a need for standardisation. There is momentum, however, and it seems certain that the speed advantages of wireless USB will make it a strong contender in the wireless-connectivity stakes.