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CES 2007: USB goes wireless
12:56AM
The technology uses the Ultra Wide Band (UWB) WiMedia wireless technology to transmit data at speeds of up to 480Mbit/s at a range of three metres and 110Mbit/s at 10 metres. Products that conform to the specification will be known as Certified Wireless USB to distinguish them from proprietary forms of wireless connections.
The initial products to be shipped will be Wireless USB dongles that plug into PCs' existing USB ports, and Wireless USB hubs that other devices, such as printers, will connect to. In the future, though, Mini PCI and PCI Wireless USB adaptors will be available for PCs, while devices will ship with integrated Wireless USB, which will give the best performance.
"Dongles and USB hubs are not native Wireless USB," said Jeff Ravencraft, chairman and president of the USB Implementers Forum. "Performance won't be optimal, but you'll still get good performance of around 100Mbit/s."
The WiMedia UWB technology that Wireless USB uses requires more power than Bluetooth, but Wireless USB is more efficient.
"Wireless USB uses more power than Bluetooth, but then we're sending data at 500 times the speed," said Preston Hunt, technology marketing manager of Wireless USB and UWB at Intel. "We don't use 500 times the power, though, so it's more efficient than Bluetooth."
Wireless USB has one important feature that Bluetooth doesn't: a sleep mode. When the connection isn't being used, the host can tell a device to go into a sleep mode that barely drains any power.
Bluetooth still has its place in the world, though, particularly for low bandwidth applications, such as headsets. Wireless USB will, instead, be the preferred method for large data transfers.
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"We chose not to define things to strictly at this point in order to let the market innovate," said Hunt.
One of the big problems with Bluetooth was that it was often difficult to use. This is something that Wireless USB hopes to overcome with two methods of pairing devices together: cable and numeric compare. The cable connection requires connecting a Wireless USB device to a PC's wired USB port to configure the wireless connection. Once done, the cable never has to be used again. Numeric compare automatically generates a code between two and four digits. User intervention requires that the code is accepted in some way on both the host and device. The USB Implementers Forum also requires that any device with a screen has to support numeric compare. Security is another issue that has been covered, with the requirement that every Certified Wireless USB device has to have a secure connection using 128bit AES encryption.
The use of UWB as the wireless standard means that Wireless USB devices won't interfere with existing 802.11 wireless kit, which operates in the 2.4GHz band. In the US Wireless USB devices will operate between 3GHz and 10GHz.
"The lower frequencies are preferable, as they have higher ranges," said Hunt.
The use of UWB frequencies in Europe is a different issue, though. The interim solution is that products sold in the UK will initially operate in frequencies above 6GHz. The lower frequencies will eventually be used, but European law requires the implementation of Detect and Avoid (DAA). This technology scans the available frequencies and builds a map of what's being used. It then switches to a free channel to prevent interference. For these reasons, products won't start being shipped in the UK until around April/May time.
