Report No. ET 98-6       ACTION IN DOCKET CASE    September 14, 1998

   INQUIRY ON UNLICENSED ULTRA-WIDEBAND TRANSMISSION SYSTEMS
                       (ET DOCKET 98-153)

     On its own motion, the Commission has initiated an inquiry to investigate permitting the
operation of ultra-wideband (UWB) radio systems on an unlicensed basis under Part 15 of its
rules.  UWB operation may provide radar systems where precise distance resolution is required
and covert voice or data communications that overcome multipath problems.  Through this
inquiry, the Commission is seeking input to evaluate UWB technology and to determine the
standards and operating requirements that are necessary to prevent interference to other users of
the radio spectrum.  Upon review of the responses to this inquiry, the Commission will determine
whether to propose any changes to the rules.

     UWB radio systems typically use extremely narrow pulse (impulse) modulation or swept
frequency modulation that employs a fast sweep over a wide bandwidth.  Because of the type of
modulation employed, the emission bandwidths of UWB devices generally exceed one gigahertz
and may be greater than ten gigahertz.  In some cases, these pulses do not modulate a carrier. 
Instead, the radio frequency emissions generated by the pulses are applied to an antenna, the
resonant frequency of which determines the center frequency of the radiated emission.

     The current Part 15 rules pose two primary obstacles to the implementation of UWB
technology.  First, the wide bandwidth of UWB systems emissions may result in their fundamental
emissions being transmitted into the TV broadcast bands and into restricted frequency bands. 
Generally, operation within these bands is prohibited under the Part 15 rules.  Second, the current
emission measurement procedures specified in the Part 15 rules were developed for narrowband
systems and may be inappropriate for, and pose unnecessary restrictions to, UWB technology. 
For example, the measurement procedures require the application of a pulse desensitization
correction factor.  This correction factor will cause UWB systems to exceed the peak emission
limits currently permitted under Part 15.



     The Commission believes that UWB technology has unique attributes that could lead to a
wide variety of new beneficial uses that may be in the public interest.  Radar systems are currently
being developed to detect buried objects such as plastic gas pipes or hidden flaws in airport
runways or highways.  Other radar systems would be used as fluid level sensors in difficult-to-
measure situations such as oil refinery tanks and other storage tanks.  Public safety personnel have
expressed a desire for radar systems that can detect people hidden behind walls or covered with
debris, such as from an earthquake.  Public safety personnel also have expressed a need for UWB
communications systems that can operate covertly.  These communications systems could also be
employed by heavy industrial manufacturers to overcome multipath and machinery-generated
radio noise.

     Action by the Commission August 20, 1998, by Notice of Inquiry (FCC 98-208). 
Chairman Kennard, Commissioners Ness, Furchtgott-Roth, Powell and Tristani.

                            - FCC -

     Office of Engineering and Technology contact:  John A. Reed at (202) 418-2455.