DEBATE ON UWB STANDARDS HEATS UP AT IEEE WORKING GROUP

The process toward a final 802.15.3a standard has divided some of the largest U.S. equipment makers (CD July 15 p3). The standard covers UWB devices for communications applications. The CDMA-based proposal developed by XtremeSpectrum and Motorola is based on a “traditional” UWB system that occupies a broad swathe of spectrum under limits set by the FCC in a Feb. 2002 order. That of the Multiband- OFDM (Orthogonal Frequency Domain Modulation) Alliance (MBOA), which includes Intel, TI, Panasonic and Samsung, relies on a frequency-hopping technology over multiple bands, which also is allowed under the FCC order, sources said. The standard will accommodate short-range UWB applications, allowing data rates of 110 Mbps at 10 m and up to 480 Mbps at shorter distances. Sources have said the debate over 802.15.3a is similar to standards wrangling in the Wi-Fi arena over 802.11b. The IEEE’s 802.11 standards focus on wireless local area networks, while 802.15 covers wireless personal area networks (PANs) -- the space around a user that extends 10 m in all directions.

“It is possible you could ultimately end up with multiple standards,” an industry source said, adding that wouldn’t be an ideal scenario. “We would like to see it get down to a single standard. That’s not likely at this meeting.”

The debate has involved whether a frequency-hopping (FH) system would have to be tested for compliance with the hopping function turned off. In July, XtremeSpectrum and Motorola asked the FCC to provide guidance on the parts of its UWB rules that covered such compliance testing (CD July 29 p8). The companies said there were 2 proposed interpretations of the rules: (1) To allow FH devices to possibly emit energy in excess of FCC limits, even if a compliance test were passed. (2) To operate at lower power levels than non-FH systems in order to comply. Backers of the MBOA proposal have said their draft standard would comply with the FCC’s rules for testing.

FCC Office of Engineering & Technology Chief Edmond Thomas said last month the Commission hadn’t decided whether it would offer guidance in response to that request. He said the agency basically had told participants in the standards debate to have their own “food fight.”

“I think the signals we have been getting from the FCC are really more that they are studying the issue and they don’t want to rule on this right now,” an industry source said. “They feel they don’t have enough information and they don’t want to rush to judgment.”

At an IEEE working group meeting in San Francisco in July, the MBOA proposal received 60% of votes cast, shy of the 75% needed for confirmation, said Chris Fisher, vp-mktg. for XtremeSpectrum. If the proposal again fails to win more than 75% in a confirmation vote at the meeting Sept. 15-19, the process “resets” and leaves on the table the 3 proposals that received the most support during the previous process of narrowing down the plans submitted for a draft standard. Under that scenario, the XtremeSpectrum-Motorola draft would be in the running as the working group would start anew on narrowing the field to a single proposal, Fisher said.

“If we reset the process, there will be lots of discussion of the performance issues that have been raised since the San Francisco meeting,” Fisher said. Among the hot points since then have been the frequency-hopping issue as it relates to FCC rules for compliance testing and the overall complexity of the implementation of the MBOA proposal, he said.

“This is a political hot potato,” Fisher said. “We believe there are real manifestations of interference effects on incumbent real-world systems,” he said. Backers of the XtremeSpectrum-Motorola approach can demonstrate there is a negative effect on TV reception from the multiband transmission contemplated by the MBOA coalition’s approach, he said. Fisher said the odds that the MBOA proposal would receive more than 75% of the votes at the Singapore meeting were “very, very low.” He said: “This issue is not going to have total clarity in that time frame.”

But Ben Manny, Intel dir.-wireless technology development, said the MBOA proposal had significant momentum. “It has a really good chance of being confirmed at the next meeting,” he said. In the somewhat arcane procedures of IEEE approval processes, the confirmation vote could come at the working group meeting this month or later, Manny said. Some of the concerns raised about the MBOA approach are more market-oriented, including those who say the approach is too complex and would delay the time-to-market of products, he said. “We had similar concerns in the group when we started to look at OFDM” in these bands, Manny said. “After studying and looking at the advantages in terms of energy capture, we decided it was a good trade-off.” Other concerns have centered on intellectual property. The MBOA backers aren’t viewing the standards work in that area “as a way to incur revenue through intellectual property,” Manny said. “We would like to adopt a zero-licensing fee.”

The other concern has been on how to measure energy from the type of multiband, FH system contemplated by the MBOA proposal, Manny said. “We should be able to address all those concerns at the September meeting,” he said. One factor that may help is that a company is undergoing a certification process now at a private lab for an UWB device that matches the MBOA proposal, he said The radio uses the chip-making technology CMOS and is close to the multiband OFDM radio technology in the Intel-TI proposal. The results from the private lab would have to be turned over to the FCC in the equipment certification process, Manny said. “This certainly would be one way to indicate to the FCC that energy can be measured from these radios the same way you would measure emissions from any UWB radio,” he said.