Incisor overview: Ultra-wideband (UWB)
Many short range wireless technologies – Bluetooth and Wi-Fi, for instance - provide the ability to connect devices and transfer data wirelessly.
There is growing interoperability between many of the consumer electronics devices that we use – such as digital cameras and camcorders, PDAs, cell phones, portable MP3 and DVD players, HDTVs etc. Up until now, Bluetooth has been the most widely used technology for connecting devices, yet its relatively slow data transmission (maximum 3Mbps) means that it is simply too slow to be viable when it comes to transferring large volumes of data.
Today it is not unusual for portable devices such as camcorders to have files of several GB in size. Yet sending a 5GB file across Bluetooth v2.1+EDR at 3Mbps would take 15 hours, draining the battery of a cellphone, for example, and testing the patience of most users.
What is really needed is the ability to send data wirelessly from one device to another at the same or better speed than a USB cable (see below). Ultra-wideband (UWB) - potentially working alongside Bluetooth, Wi-Fi or WiMAX - can deliver the goods.
UWB is an emerging technology that operates in the 3.1 to 10.6 GHz frequency bands and communicates over short distances at high speeds and with very low power consumption, and is ideally suited for streaming multimedia in the home or office environment.
Not just another RF device
UWB is unique in the way that it operates. Other wireless technologies operate by transmitting continually at a specific frequency, whereas an UWB transmitter sends out very short - 30 picoseconds - pulses or bursts of data at ultra-low power levels. These pulses radiate outward in a wide band, using a proprietary pulse signature. Rather than using one frequency, UWB uses multiple frequencies simultaneously. The receiving device needs to know the sender’s pulse signature in order to be able to ‘listen’.
One big advantage of UWB’s ultra-low power, short bursts and proprietary pulse signatures is the fact that several UWB networks can co-exist, without interference or data security issues. It is so secure, in fact, that UWB has been in use by the military since the 1960s.
How fast?
UWB is intended to work best over relatively short distances – up to about 30 feet (10 meters), the same bubble of connectivity targeted by Bluetooth. Optimum data speeds of 480 Mbps will be possible at distances from six to ten feet (2-3 meters). As devices become further apart, so data rates drop. At 30 feet, UWB companies are aiming to provide 100 Mbps. In future, we should expect UWB to move to 2 Gbps (gigabits per second). This kind of speed is needed for so-called ‘trick-play’ features when streaming video – pause, fast-forward, rewind etc.
UWB & USB
There are more than 2 billion wired USB connections in the world today. Not only is USB the de facto standard in the PC industry, it is now also used by cameras, cellphones and many other consumer electronic devices. But a cable is a cable is a cable, and as such is old technology.
As the world goes wireless, Certified Wireless USB, which uses UWB technology, will replace the USB cable, and is intended to offer the speed and security of a cable with the ease-of-use of wireless technology. Certified Wireless USB performance is targeted at 480Mbps at 3 meters and 110Mbps at 10 meters.
Who is looking after me?
The governing body for UWB is the WiMedia Alliance – www.wimedia.org. This is a 350+ member global nonprofit organization that defines, certifies and supports enabling wireless technology for multimedia applications.
The WiMedia Alliance has overseen the specification of the WiMedia Radio, which is an implementation of Ultra-wideband (UWB) that enables short-range, high-speed (480Mbps and beyond) multimedia data transfers, typically consuming less than 2mW/Mbps. The Alliance is championing the rapid adoption and standardization of UWB worldwide and has established a certification program. Certification ensures any two WiMedia-based devices will not interfere with each other’s operation.
UWB & Bluetooth
With a view to extending Bluetooth’s role as the most popular way of connecting personal electronics devices together, the Bluetooth Special Interest Group chose to align with the WiMedia Alliance, and UWB will become a partner technology for Bluetooth. Future Bluetooth-enabled devices having the capability of switching over to an UWB radio when a large volume of data needs to be transferred quickly. Once the job is done, the UWB radio will be switched off and the device will revert to classic Bluetooth. Thankfully, all of this will be invisible to the consumer. They – the consumers – will simply find they have been able to swap whole music albums or movies with friends or colleagues in short amounts of time, and without depleting their batteries.
The UWB/Bluetooth marriage hasn’t happened quite as quickly as some would like, and so, in order to provide a ‘here and now’ solution, the Bluetooth SIG has also brought Wi-Fi into the picture. A technology called the Alternative MAC/PHY means that a Bluetooth device will be able to switch on a Wi-Fi or UWB radio to achieve high speed data transfers. In the longer term, UWB’s substantially higher data transfers and very low power consumption should see it replace Wi-Fi in the high speed Bluetooth sector.
