Skip to main content

House Wants Answers on Receivers' Role in Spectrum Sharing

The House Communications Subcommittee wants industry input
on Thursday on how to allow spectrum users, like broadcasters, wireless
companies and the government, to occupy increasingly close quarters without
"stepping on each other's toes."

That is according to a majority staff memo on a Nov. 29
hearing in the subcommittee on "The Role of Receivers in a Spectrum-Scarce

The issue is growing in importance given a number of FCC
initiatives to boost spectrum efficiency and use, including allowing unlicensed
devices to share the so-called "white spaces" in the broadcast band,
moving broadcasters to make room for wireless companies, the FCC's so far unsuccessful
attempt to allow LightSquared to operate alongside GPS spectrum, and the FCC's
recent move to loosen rules on terrestrial use of satellite spectrum.

"Good fences make good neighbors," say the
staffers, "but how do you know how high to build your fence or what
materials to use if you don't know who your neighbors might be in the future or
precisely what they will be doing on their lot?"

They point out that the two main "fences" are
guard bands on the spectrum side and filters and power limits on the
transmitter/receiver side. Some of the questions that the subcommittee majority
wants answered include:

"Can smart engineering and forward-looking spectrum
strategies account for the possibility of unanticipated technologies and uses
in adjacent spectrum bands and help prevent today's decisions from limiting
flexibility in the future? How do we promote such flexibility without
unreasonably increasing the cost of services and devices," emphasizing the
receiver side of the fence.

A spotlight was put on the receiver issue by the failure of
LightSquared ultimately to secure an FCC waiver to use its satellite spectrum
to create a wholesale, terrestrial mobile broadband network. The FCC initially
granted the conditional waiver, but put that effort on hold -- and LightSquared
into bankruptcy -- after it was determined that sensitive GPS receivers in an
adjacent band were being interfered with because they were picking up in-band
transmissions, meaning that LightSquared's transmissions were within its band,
but the GPS receivers were picking them up anyway.

Government users are also being called on by the Obama
administration to find ways to share more of their spectrum with commercial

More recently, Dish network has complained that the FCC's
new proposal to loosen restrictions on terrestrial use of satellite spectrum Dish
owns would "cripple" their plans for a wireless 4G network because of
restrictions that protect an adjacent -- currently unoccupied -- band from
interference. That issue is not directly addressed in the memo, but could be
brought up in the hearing.

Scheduled to testify at the hearing are Brian Markwalter,
senior VP, Consumer Electronics Association; Ron Repasi, deputy chief, Office
of Engineering and Technology, FCC; and Pierre de Vries, senior adjunct fellow,
Silicon Flatirons Center, University of Colorado.