After a couple of years of deadlocked negotiations over standards in the IEEE, developers of ultra-wideband (UWB) radios now have a more solid regulatory landscape against which to develop products.

The European Electronics Communications Committee (ECC) has approved the use of UWB devices in the range from 6-8.5GHz, subject to the technical limits stipulated by the FCC in the US, without requiring the use of interference mitigation techniques. The separate national regulators now have to approve the recommendation.

“They have decided to only adopt the decision for the band above 6GHz and the rest has all gone back a bit to the drawing board,” says James Page, manager for radio spectrum regulations at Nokia UK. “I don’t think there’s anything more to do on that [above 6GHz].”

This means Europe, the US and Japan now have a common chunk of the FCC’s original 3.1-10.6GHz spectrum available, so the same products can theoretically be sold into all three regions. However, at the moment there is not actually much product using that spectrum – many UWB developers have been concentrating on the lower frequencies, which represent an easier technical challenge, certainly for CMOS, and offer better range.

Freescale has been quick to produce UWB silicon

Any products working in these lower bands are currently illegal in Europe, although there is ongoing consultation that should clear up the situation later this year. Questions to be answered include how to implement the detect and avoid (DAA) and low duty cycle (LDC) mitigation techniques, and whether to allow radios without these to operate in a section of spectrum at 4.2-4.8GHz for a limited time period.

“Our current offering is from 3GHz to about 4.8GHz – it’s what we can achieve in CMOS,” says Jason Ellis, senior manager of business development at US firm Staccato Communications.

“But having built a single chip [device], what we’re able to conclude is that, because the RF is such a small part of the overall implementation, we believe we can do higher frequencies in a single chip in CMOS. No one has pushed the envelope quite like this in CMOS. That’s why most people do SiGe for the front end.”

Another recent announcement – the selection of the multiband OFDM version of UWB by the Bluetooth Special Interest Group (SIG) – will drive developers to build chips operating at the higher frequencies. The SIG wants the UWB-based high data rate version of Bluetooth to operate above 6GHz.

Hard on the heels of that announcement, Cambridge UWB firm Artimi said last week that it had taped out UWB RF silicon that supports 3-5GHz and 6-9GHz operation. The ECC limit at 8.5GHz, chosen to protect a certain class of military radar, will be re-examined in the current consultation leading up to its July meeting and could be extended to 9GHz as it is elsewhere.

Moore: European radios will be "performance impaired"

“We would have liked it to be 6‑9GHz. It makes it more difficult to build a completely simple radio that operates anywhere in the world. Effectively, what it means is that European versions of global radios will probably be performance impaired compared with US and Asian counterparts,” says Mark Moore, CTO of Artimi.

“At CEPT [the European Conference of Postal and Telecommunications Administrations] there was a huge volume of lobbying against the low-frequency bands from all kinds of people, most prominently the cellular operators and manufacturers, but in the high band there was almost no objection at all.”

The Bluetooth SIG’s decision to go with the multiband OFDM version of UWB (which is being developed by the WiMedia Alliance) means WiMedia has now been chosen as the basis for two major consumer UWB markets – Bluetooth and certified Wireless USB.

Although US networking devices manufacturer Belkin has opted to use the alternative direct sequence technology from the UWB Forum group as the basis for its own CableFree USB products, interoperability between devices from different manufacturers should be a certain guarantee of a larger total available market.

WiMedia therefore has a potentially powerful position and, after abandoning the deadlocked, three-year-old IEEE standards process in favour of the European organisation ECMA, it has a route to ISO standardisation. The primary reason for cheerfulness within the UWB Forum is the fact that direct sequence products are already available, albeit currently for the US market only. Moore is of the opinion that the Forum could align more closely with the IEEE work on a UWB front end for ZigBee.

A UWB demo for high definition TV

Following the Bluetooth decision, WiMedia member Staccato says it will proceed down a route to integrating more than one protocol into a single radio chip.

The first step towards this will involve combining existing Bluetooth technology with Staccato’s certified Wireless USB product, which uses its Ripcord devices based on one card, and USB dongle reference designs for use in PCs.

It will then port Bluetooth-over-UWB software profiles on to Ripcord silicon, and eventually integrate any new silicon blocks required by the Bluetooth-over-UWB specification into the chip.

Staccato’s Ellis says its MAC is divided into a hardware lower MAC and an upper MAC in firmware that boots from memory, to enable it to support extra protocols.

“The key reason why we’ve been promoting ourselves as Wireless USB until this point is that’s the only market that will happen in 2006,” he says.

Pulsers

A major 36-partner European project to develop UWB technology entered its second phase in February. Pulsers II, which has total funding of €22m, will concentrate on developing applications. The first, two-year period of the project focused on technology exploration, including the interference mitigation techniques that are likely to be required in the lower bands.

“We have work packages now organised following different application streams,” says Dr Sven Zeisberg, who is coordinating the project. “Some are for very high data rates, and each of them will implement a verification platform, and… build up a demonstration platform. We will also have three work packages for low data rate — two dedicated to low data rate communication together with location tracking functionality, and one package without location tracking, just robust near-field communication.”

Pulsers is among the organisations that will submit evidence to the European Radio Spectrum Committee, and Zeisberg says it is currently embarking on some more detailed measurement experiments to determine more accurately how UWB emissions affect other wireless services.

www.pulsers.info