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Ultra Wideband:FAQs

1. What is UWB?

UWB is a technology developed to transfer large amounts of data wirelessly over short distances, typically less than ten metres. Unlike other wireless systems, which utilise spectrum in discrete narrow frequency bands, UWB operates by transmitting signals over a very wide spectrum of frequencies.

It is an alternative to other wireless technologies such as Bluetooth and WiFi that create Personal Area Networks (PAN). The principal advantages of UWB over these technologies are much faster data transfer rates (100 Mbps or greater) and extended device battery life. It may also offer cost advantages if chipset production volumes are sufficiently high.

2. How does it work?

Ultra wideband is a new standard for devices that send very short pulses of information over small distances. Such devices broadcast signals over a wide range of different frequencies at the same time, meaning that they can use relatively simple equipment to transport huge data files.

3. Where would I use it?

UWB might be used to deliver wireless connections between electrical devices, simplifying installation and removing the need for unsightly wires.

For example, it could link:

DVD players with displays and speakers,
Digital cameras/camcorders with personal computers
PCs and monitors
PDAs, smart phones and other computing devices in a local area.

Other more specialised applications of UWB include radars that can allow fire-fighters to see through walls or safety engineers to probe the ground to find anomalies such as cracks in runways. UWB could also enable wireless sensors, asset tracking and automotive systems.

4. What are its benefits?

An independent report has found that UWB has the potential to make a substantial contribution to the UK economy, generating significant revenue from new goods and services over the next 15 years.

Consumers will benefit from new and exciting applications in their home that will allow their electronic devices to talk to each other without wires, making life easier and more clutter-free.

This will create a new market for businesses of all sizes to develop and market innovative new products and services in a licence-free environment.

5. What is Ofcom proposing?

Ofcom is seeking industry views on whether to allow Ultra Wideband devices in the UK, potentially on a licence-exempt basis. We recognise the risk that interference caused by UWB may affect existing spectrum users so we plan to impose a restrictive mask that will limit this interference as much as possible. Finally, we will work with the EC to develop and adopt an appropriate mask in a harmonised approach across the region.

6. What is the basis for Ofcom’s involvement in this?

Under current UK law, it is illegal to install or operate wireless devices unless those devices are subject to a specific licence or licence exemption. If UWB devices are to become lawful in the UK, Ofcom needs to issue licences, or licence exemptions, for those devices. No relevant licences or licence exemptions currently exist.

As part of its thinking as to whether such licences or licence exemptions should be issued, Ofcom must take account of the Communications Act, which requires us to secure

The optimal use of the radio spectrum
Availability of a wide range of electronic communications services
Availability and use of high speed data transfer services
Investment and innovation wherever possible

It is our provisional opinion that allowing UWB will allow us to achieve each of these things.

However, the same Act also requires us to take into account the different needs and interests of all persons wishing to make use of the spectrum, which is why we are conscious of the need to guard against interference.

7. What is the risk of allowing UWB?

UWB does transmit in areas of the spectrum used by others. However, its transmissions are at such a low level that in general Ofcom considers that it is unlikely to be material.

The likely impact of UWB devices on their environment has been tested regularly, dating as far back as 1999. The first tests in the UK revealed negligible interference on cellular systems, home TV receivers and aircraft navigation.

In 2002 the Radiocommunications Agency commissioned an independent report which demonstrated that UWB may have a detrimental effect on a nearby 3G handset.

This report also made the point that the level of interference would depend on how UWB was being used. If, for example, a digital TV signal was being sent across a room, the interference to nearby devices would be high. On the other hand, if you were just downloading music files to a HiFi the level of interference would be drastically reduced.

It is important to bear in mind that after five years of testing and reports from around the world, there is still little consensus on the level of interference likely to be caused by UWB. In the consultation document we set out our views on the testing and modelling performed to date.

8. Will the risk of interference increase if there are a lot of UWB devices?

There seems to be a correlation between the concentration of UWB devices in an area and the likely risk of interference to other spectrum users in that area. However, we intend to design the technical mask in such a way that interference will be kept to a minimum.

9 .What is a mask?

A mask is a graph showing how much power a UWB transmitter can radiate in each area of the radio spectrum. Most power is concentrated in the central part of the graph - the inband portion - with much stricter restrictions on radiation in the outband part on either side.

10. How will this one be defined?

Ofcom has proposed a mask which it considers to be appropriate based on the need to balance the risk of potential interference with allowing UWB to work cost-effectively and on a global basis.

11. Which users will be most affected by interference?

At this stage we are consulting on the potential introduction of UWB devices and whether our present assumptions as to the likely effects of UWB are reasonable. The results of this consultation and the additional studies we have commissioned will put us in a better position to understand the scale of any potential effects.

12. Would it not be better to wait until we know for sure what the effects may be?

We feel strongly that we need to form a policy approach to UWB as soon as possible. The debate is gathering speed across Europe and we want the UK to have a firm line on it so that we can lobby strongly for an optimum result for the UK as part of any harmonisation across Europe .

13. What were the recommendations of the report commissioned from Mason Consultancy?

That Ofcom pursues a policy within Europe of promoting the draft ETSI mask for UWB emissions, possibly subject to modifications of the roll-off below 3GHz. This recommendation is based on the consultants’ understanding from manufacturers that UWB chipsets can meet the tighter limits applying at the edge of the mask relative to the FCC mask, such that benefits predicted in this study are not affected.
There appears to be scope for tightening the roll off of the ETSI mask below 3 GHz to a level of –85 dBm/MHz without eroding UWB benefits. At this PSD level, the consultants calculated that costs to UMTS operators will be minimal. Therefore, there does not appear to be any compelling reason for applying power restrictions below this level.
Both the upper and lower bands should be made available for UWB^(-1-). Restricting UWB to the lower band would potentially constrain future value for no obvious benefits. Restricting UWB to the upper band only would be value destructive.
There is scope for further investigations into the interference effects of UWB on various services, including wireless broadband, UMTS and aeronautical radar. This might lead to additional insights in relation to the detailed regulation of UWB emissions. However, the consultants think it unlikely that such analysis would have any significant impact on the overall conclusions.

14. Have you considered how this will affect future systems and technologies?

We decided not to consider the potential cost of interference from UWB to future systems such as 4G. This is because we believed it would not be possible to quantify the cost to systems which in some cases have not yet been invented and for which there are no specific deployment plans.

We have however decided it would be appropriate to investigate further the likely impact on services in the 2500-2690 MHz frequency band (sometimes called ‘the 3G expansion band’), and have commissioned a further study in this area. Ofcom intends to publish the results of this study once available in the spring.

15. Have other countries allowed UWB? What were the results?

On 14 February the US Federal Communications Commission (FCC) authorized the commercial deployment of UWB technology, though subject to technology and operational constraints.

No devices have yet been brought to market in the US so it is too early to say whether the new technology has been a success or not.

Footnotes:

1.- This recommendation is based on consideration of existing uses of this spectrum; it is outside of the scope of this study to consider whether there are any future uses of spectrum in either the upper or lower bands that might be constrained by UWB deployment.