> Document IWG-2/004

Author: A. Renshaw

18 April 2001

UNITED STATES

**PRELIMINARY VIEWS ON WRC-03**

WRC-03 Agenda Item 1.16: to consider allocations on a worldwide basis
for feeder links in bands around 1.4 GHz to the non-GSO MSS with service
links operating below 1 GHz, taking into account the results of ITU-R
studies conducted in response to Resolution 127 (Rev.WRC-2000), provided
that due recognition is given to the passive services, taking into
account No. S5.340

**ISSUE:** Additional allocations to the non-GSO MSS for feederlinks in
the bands 1390-1393 MHz and 1429-1432 MHz at WRC-03.

**BACKGROUND:** A total of l.525 MHz (space-to-Earth) and l.9 MHz
(Earth-to-space) are presently allocated on a worldwide primary basis to
the MSS below l GHz and 300 kHz (Earth-to-space) is allocated for land
MSS on a worldwide primary basis. These allocations are for both the MSS
service links and feeder links. Since these allocations at WARC-92 and
WRC-95, the Radiocommunication Bureau has identified 25 non-GSO MSS
networks at frequencies below l GHz, at some state of coordination under
 **S9.11A**/Resolution **46 (Rev.WRC‑97)**, and nine non-GSO MSS
networks at the advance publication stage only. However, it appears that
many of the proposed networks cannot be implemented in the existing
allocations because there is not enough spectrum readily available in
the allocated spectrum. Additional feederlink spectrum outside of the
currently allocated bands would provide dedicated feederlink spectrum
and free up existing allocations for scarce service link spectrum.
WRC-97 approved Resolution 127 to study sharing techniques for NVNG MSS
\< 1 GHz feederlinks (Earth-to-space) in the 1390-1400 MHz band, and
space-to-Earth feederlinks in the 1427-1432 MHz band. As a result of the
favorable initial studies in these bands, WRC-00 approved Agenda Item
1.16 to consider allocations at 1390-1393 MHz for uplink feederlinks,
and 1429-1432 MHz for feeder downlinks for the non-GSO MSS service with
the understanding that Resolution 127 studies must be completed
including testing of near-flight hardware to validate the theoretical
studies approved earlier.

Sharing studies completed in the ITU-R under Resolution 127 include a)
out-of-band sharing with the radioastronomy service by meeting
Recommendation RA.769-1 levels of --255 dB (W/m^2^/Hz) for the 1400-1427
MHz band, b) out-of-band sharing with EESS by meeting Recommendation
SA.1029-1 requirements of --171 dBW/27MHz for in-band pfd levels, c)
in-band sharing with the EESS by meeting the time avoidance criteria, d)
sharing with fixed and mobile services on the basis of not exceeding the
pfd levels established for sharing in the adjacent bands of --146
dBW/m^2^/4kHz (since no level had been established for the 1429-1432 MHz
band), and e) sharing with the radiolocation service by equipping the
non-GSO MSS satellites with adequate filtering. In addition to the
above, uplink sharing with the fixed and mobile services can be
accommodated by geographical sharing of the small number of remotely
located feederlink stations.

**PRELIMINARY VIEW:** The U.S. supports allocations in the 1390-1393 MHz
and 1429-1432 MHz at WRC-03 for the non-GSO MSS pending completion of
studies under Resolution 127. The proposed allocations are in bands
close to the passive services band at 1400-1427 MHz that must be
protected from out-of-band and spurious emissions. Studies have shown
that interference to radio astronomy and the other passive services can
be avoided using various techniques including low-power transmitter
levels, choice of modulation, symbol shaping, output filtering and band
limiting filters, the use of which can minimize the band separation
necessary to meet the recommended interference threshold levels for
protection of these services. The U.S. expects that the hardware testing
to be completed this year will confirm the theoretical results already
approved by the ITU-R for the protection of the passive services. Other
sharing results will be similarly definitive, and will allow allocation
of these bands at WRC-03. (04/18/01)