UWB Clearing the hurdles but its a long race

Ultra-Wideband or UWB technology was first given the green light by the US Federal Communications Commission (FCC) back in 2002. It became an important milestone for UWB as it provides a reference for the technology’s proponents seeking similar endorsement from other regulators. However, UWB-enabled devices are still far from common, particularly outside the US, even though the technology can be used for many applications.

With a much higher data rate (up to 480 Mbps), lower power requirements and the ability to accommodate more devices within a given area, UWB is being touted as a better technology than Bluetooth for short-range connectivity.

Furthermore, companies developing UWB solutions envisage that the technology eventually will be used to connect most electronics products such as computers, mobile phones, digital cameras, printers, game consoles, HDTV, DVD players, audio hi-fi and so on. Some companies are also using the technology to develop wireless USB solutions.

In addition, there are other more specialised applications for UWB which including radar and imaging systems. With the ability to penetrate obstacles and to provide precise positioning and tracking, UWB can also be used to develop systems for search and rescue operations, surveillance and health purposes. These include ground penetration radar, wall imaging, through-wall imaging, surveillance and medical imaging.

Automotive manufacturers have also embraced UWB, using it for collision detection radar systems. These, unlike comms systems, operate at very high
frequency bands (typically 24 GHz and 79 GHz) and have met with fewer regulatory obstacles an, what's more, vehicles equipped with UWB-enabled automotive radar are already available in some parts of Europe.

As well as the high data rate, equipment manufacturers are also drawn to UWB because its low power to noise emissions mean the technology is unlikely to interfere with other RF equipment and can usually be exempted from licensing conditions.

However, UWB radios do generate pulses that cause signals that spread across a wide bandwidth range. Thus UWB signals can be regarded as occupying a very wide range of radio frequency spectrum albeit at very low power.

In point of fact, regulators do use bandwidth as a key parameter for UWB definition (typically more than 500MHz). As some measure of comparison it should perhaps be borne in mind that every WiFi channel occupies about 20MHz, each 3G channel occupies 5MHz and each GSM channel occupies 0.2MHz.

Because of the ultra-wide bandwidth, existing radio frequency users (e.g., mobile, radio navigation and satellite) have raised concerns about the possible interference to their systems, particularly when there are multiple UWB devices operating nearby. These objections have tended to impede the development of UWB products as regulatory authorities try to address the concerns of all existing radio users. Moreover, most countries are not prepared to adopt the FCC’s rules and the International Telecommunications Union (ITU) has been unable to harmonise the power limits for UWB.

As a result, most regulators are taking a cautious approach and could well apply more stringent power limits in certain frequency bands. They may also impose additional rules such as limiting the use to indoor only, allowing only specific group of users (for imaging systems, for example), or requiring devices to have specific features (such as detect and avoid). These will add complexity to the design of UWB devices and could result in both poorer performance and higher costs.

Apart from the US, some countries in Europe, as well as Japan and Korea, have already formulated the regulations pertaining to the use of UWB devices. Japan’s Ministry of Internal Affairs and Communications indicated recently that it will review the technical conditions for UWB communications systems while the Infocomm Development Authority of Singapore (IDA) is also in the process of firming-up its regulatory framework for the technology.

One of the major concerns for UWB is the current lack of a global standard and most of the UWB products on the market are proprietary. However, there are two industry organisations leading the push to promote and standardise UWB worldwide for wireless personal area networking – the WiMedia Alliance (Multi- band OFDM) and UWB Forum (Direct Sequence UWB) and increasing numbers and varieties of WiMedia-based UWB products are beginning to appear.

Of course, UWB is not the only technology for high-speed short-range connectivity. The IEEE 802.11n, an enhanced wireless LAN specification, will see data rate increased to 100 Mbps and while 802.11n is not yet commercialised, it has a long range and is also a suitable wireless interface for home digital equipment. So, even though the environment for UWB may be encouraging, it is still too early to say if the technologycan or will become a huge success.