ARRL, IARU Contribute to ITU Ultra-Wide Band Studies:

The ARRL and the International Amateur Radio Union (IARU) have contributed to International Telecommunication Union (ITU) Radiocommunication Sector (ITU-R) studies of Ultra-Wide Band (UWB) short-range RF technology and its potential to interfere with licensed radio services. UWB devices operate by employing very narrow or short-duration RF pulses that result in very sizeable, or wideband, transmission bandwidths. In February 2002, when the FCC released its 122-page Report and Order (R&O) in the UWB proceeding, WT Docket 98-153, it expressed its belief the technology "offers significant benefits for government, public safety, businesses and consumers." But the Commission also allowed that UWB's "substantial benefits" could be outweighed if UWB devices interfered with licensed services and "other important radio operations."

"ITU-R Task Group 1/8 struggled to characterize UWB emissions, such as what frequency ranges, pulse characteristics and power levels," said ARRL Chief Technology Officer Paul Rinaldo, W4RI. Rinaldo and ARRL Technical Relations Specialist Walt Ireland, WB7CSL, served on TG 1/8, took part in many of the Task Group's US studies and preparatory meetings and served as part of the US delegations to ITU-R TG 1/8 international meetings. The League and the IARU also provided the characteristics of Amateur Radio systems.

"The FCC Report and Order on UWB was a starting point for the world body to accept it, reject it or modify it," Rinaldo explained "Whatever was submitted by ARRL had to be consistent--or at least not in disagreement--with the FCC R&O, as well as survive the vetting process for all US contributions to ITU."

Prospective UWB applications include ground-penetrating radars, through-wall imaging, medical imaging and vehicle collision-avoidance systems. The FCC says its analysis indicates that UWB devices can operate on an unlicensed basis without causing harmful interference "provided appropriate technical standards and operational restrictions" are in place.

"Having described the characteristics of UWB devices," said Ireland, "then the problem was to determine how UWB emissions propagate from the device to a radio system that might be interfered with." The wide frequency range over which UWB operates made that task more difficult, he noted.

Peter Chadwick, G3RZP, represented the IARU throughout the life of TG 1/8 and made substantial on-the-spot contributions to the technical work. "The ARRL Laboratory provided basic characteristics of Amateur Radio systems--in this case related to bands between 3.1 and 10 GHz," Ireland added. Ken Pulfer, VE3PU, also contributed to the task group's work.

In the final analysis, the US did not get the rest of the world to accept the FCC's UWB R&O without question. "The Europeans in particular came up with their own ideas on UWB systems and potential interference to systems they want to protect," said Rinaldo. "As a radio service, amateurs didn't get everything they desired either, but got the characteristics of our radio systems on record."

He says four Draft New Recommendations (DNRs) on UWB characteristics, compatibility, framework and measurement and a report with radio systems gained approval at the Task Group and Study Group levels and soon will circulate to individual administrations for their approval.

"The bottom line? UWB is capable of interfering with radio services," Ireland concluded. "If the UWB device and the radio system--including antenna--are in the same room and so forth, interference is likely." Walls or distance between a UWB device and a radio system make interference less likely, he added.

"In other words, for Amateur Radio stations, UWB interference most likely would be a self-inflicted wound," Rinaldo suggested. "That is, a computer wireless UWB mouse would probably interfere with receivers in the shack operating in the same bands."

Source:

The ARRL Letter Vol. 24, No. 48 December 9, 2005

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