Ultrawide Gap On Ultrawideband


Ultrawideband--a technology in which signals are transmitted in the form of billions of extremely short radio pulses spread over a bandwidth totaling several gigahertz--is highly anticipated because it will provide the wireless personal-area-network (WPAN) connectivity of Bluetooth, but at speeds up to 500 times faster.

Despite that promise, a growing rift between the backers of separate ultrawideband (UWB) technologies has led to a stalemate within the IEEE 802.15.3a working group for WPAN charged with finalizing a standard for ultra-wideband. The two groups at loggerheads are the Multiband-OFDM Alliance (MBOA), led by Intel Corp., in Santa Clara, Calif., and the XtremeSpectrum group, led by Motorola Inc., in Schaumburg, Ill. (Motorola recently purchased XtremeSpectrum, which was based in Vienna, Va.) Their main disagreements concern how much UWB devices might interfere with other radio users, how much power they will consume, and how much the chipsets needed to relay UWB signals between devices will cost.

Athough the groups have made repeated attempts to reach a compromise, the process has bogged down. Andreas F. Molisch (SM), a researcher at Mitsubishi Electric Research Laboratories, in Cambridge, Mass., told IEEE Spectrum that "the two proposals are so far apart technologically that, in the end, it's going to be one or the other."

At the most recent meeting of the IEEE 802.15.3a working group, held in Albuquerque, N.M., during the week that ended 14 November, MBOA's proposal received 58 percent of the votes--well short of the 75 percent needed for ratification.

10 -14seconds

The accuracy of the clock needed to measure the time intervals between the 0.2- to 1.5-nanosecond-long pulses that make up the UWB signals transmitted by the PulsON chipsets produced by Time Domain Corp. in Huntsville, Ala. Time Domain is a member of the MBOA Alliance, one of two groups vying to set the UWB standard in an IEEE working group for wireless personal area networks.

The XtremeSpectrum proposal was notvoted on because of an exacting selection process that knocked out nearly two dozen other specifications. XtremeSpectrum was eliminated for the July 2003 meeting, returned to the voters' ballots in time for the September meeting after the MBOA proposal didn't garner the three-quarters majority, and scratched again by the November gathering. Molisch admits that the process of trying to reach the 75 percent threshold could continue indefinitely.

The MBOA has publicly accused Motorola of holding up the process long enough to get its UWB chips on the market in an attempt to create a de facto standard. XtremeSpectrum has already announced plans to release products this year based on its specifications. If that happens, MBOA would, no doubt, immediately return fire, releasing its own proprietary standard without the IEEE's approval. Steve Turner, business development manager for ultrawideband at Texas Instruments Inc. in Dallas, another member of the MBOA camp, says he hopes the political process is resolved before it comes to that, but the MBOA group is still pushing forward with its draft specification. "We've heard all the concern over whether MBOA was going to pick up its toys and leave the IEEE [standards process], but we're not giving up on it."

Robert F. Heile (M), chairman of the IEEE working group, told Spectrum that, despite the fuss surrounding this process, the delay in the adoption of a UWB standard will not retard the development of the market for this technology. In fact, he said, he will encourage both parties to go ahead with the production of devices based on their proprietary specifications. "I'm hoping we can get silicon [chips] out there so we can get the experience we need to write an even better standard."

Heile defends the wait-and-see approach, noting that ultrawideband "is [still] illegal in most of the world." UWB devices, by definition, share spectrum controlled by primary users, and the regulatory bodies in Europe and Asia have not issued rules that govern its use. How UWB will be implemented over most of the world is not likely to be determined until 2005. That's when Japan's Ministry of Telecommuni-cations and the European Telecommunications Standards Institute are expected to weigh in. Furthermore, he says, "802.11g [the latest in Wi-Fi] was deadlocked for two years. We've only been deadlocked for a couple of months."

Who the eventual winner will be is hard to predict. Says Molisch: "One thing is clear. Dual-mode devices, with separate radios for each specification, will not be popular for cost reasons. Hitting the price target for one radio is hard enough."