Agenda Items for WRC-2003

ANNEX 1

Resolution [COM5/27] (WRC-2000)

Development of the technical basis for coordination of radio astronomy stations
with transmitting high-density fixed systems in the
fixed service, in the band 42.5-43.5 GHz

The World Radiocommunication Conference (Istanbul, 2000),

a) that this conference has decided that the band 42.5-43.5 GHz, which is allocated to the fixed service, should become available for high-density applications;

b) that the 42.5-43.5 GHz band is also allocated to the radio astronomy service on a primary basis worldwide, and is used intensively for both continuum and spectral line observations, at a limited number of sites;

c) that radio astronomy observatories operating in the band are generally located far from urban population centres, employ very high-gain antennas and very low-noise amplifiers to receive extremely weak cosmic radio emissions over which astronomers have no control;

d) that high-density fixed system (HDFS) stations are expected to be deployed in large numbers over areas of large geographical extent in urban population centres;

e) that studies are being initiated to characterize short-term anomalous propagation from transmitting stations dispersed over a large geographical area to a single receiving earth station (area-to-point propagation);

f) that no studies are yet available on the coordination distance that may be required to protect a radio astronomy station from HDFS transmissions associated with a single urban population centre, but that, based on preliminary studies made at lower frequencies, a provisional coordination distance of 250 km may be appropriate,

to conduct studies on the coordination distance between radio astronomy stations operating in the 42.5-43.5 GHz band and HDFS stations with a view to developing ITU-R Recommendations,

to participate actively in the aforementioned studies by submitting contributions to ITU-R.

RESOLUTION [COM5/28] (WRC-2000)

Power flux-density limits in the bands 37.5-42.5 GHz for the fixed-satellite service, broadcasting-satellite service and mobile-satellite service

The World Radiocommunication Conference (Istanbul, 2000),

a) that this conference has established power flux-density limits in accordance with the provisions of Nos. S21.16.10 and S21.16.FSS for the fixed-satellite service (FSS) (space-to-Earth) in the bands 37.5-40.0 GHz and 40.5-42.5 GHz, and the mobile-satellite service (MSS) (space-to-Earth) in the band 39.5-40 GHz;

b) that, in the band 37.5-42.5 GHz, Recommendation ITU-R SF.1484 recommends power flux-density limits for non-GSO FSS systems;

c) that, in the bands 37.5-40 GHz and 40.5-42.5 GHz, the power flux-density limits adopted by this conference for GSO FSS systems are based on ITU-R studies;

d) that this conference has harmonized the allocation to FSS in the band 40.5-42.5 GHz across all the Regions;

e) that there exists an allocation to BSS on a co-primary basis in the band 40.5-42.5 GHz;

f) that there are only provisional power flux-density limits for BSS in the range 40.5-42.5 GHz;

g) that, although sharing is feasible between FSS earth stations and terrestrial stations provided that appropriate coordination procedures and/or operational techniques are employed, sharing may in practice become difficult when high geographic densities of such stations are deployed in bands heavily used by either service;

h) that the band 40-40.5 GHz has not been identified as being available for high-density applications in the fixed service,

a) that Recommendation ITU-R SF.1484 indicates that some fixed service systems employing small net fade margins and which operate at elevation angles greater than 10° in the band 37.5-40 GHz may not be fully protected from interference from FSS systems without imposing undue constraints on FSS systems;

b) that the fixed service parameters for sharing studies are given in Recommendation ITU-R F.758;

c) that new studies taking account of high-density fixed service deployments with new characteristics (as documented in Recommendation ITU-R F.1498) in some countries have been presented and discussed at this conference;

d) that the new studies submitted to this conference, in which requirements are identified for the protection of high-density fixed service systems vis-à-vis GSO FSS and non-GSO FSS systems, but on which consensus has not been reached, indicate clear-sky pfd protection requirements that are about 13.5 dB more stringent at elevation angles above 25° than the table entries in Table S21-4 for the band 37.5-40 GHz;

e) that No. S5.NGSO may provide additional protection to the fixed service,

a) that some downlink fade compensation techniques, such as adaptive power control, could reduce the operational power flux-density levels of satellite networks under normal operating conditions while enhancing the ability of FSS networks to overcome rain fading;

b) that there is a need for further study to determine the percentage of time during which fade conditions will require downlink fade compensation techniques;

c) that, within the range 39.5-42 GHz, some administrations plan to deploy FSS systems using ubiquitous very small aperture terminals,

a) that the use of downlink fade compensation techniques by satellite systems may affect the performance of fixed service and FSS links operating in unfaded conditions in the same frequency band;

b) that the use of downlink fade compensation techniques affects the design of FSS links,

1 that the limits in Table S21-4 for the bands 37.5-40 GHz and 40.5-42.5 GHz, as revised by this conference, shall be applied for verification purposes by the Radiocommunication Bureau and by administrations as of 2 June 2000 in accordance with the provisions of Nos. S21.16.10 and S21.16.FSS;

2 that, taking into account recognizing a), in the interim period before WRC-03, before an administration brings into use in Region 2 a frequency assignment for a GSO FSS network in the 37.5-40 GHz band, it shall seek the agreement of any administration in Region 2 on whose territory the power flux-density produced exceeds the values in Table S21-4 minus 12 dB,

1 to meet the requirements of No. S5.NGSO;

2 when considering regulatory provisions in relation to the band 40-40.5 GHz, to take into account that there were a number of proposals to WRC-2000 to identify the band 40-40.5 GHz for high-density applications in the FSS,

1 taking into account the resolves, to conduct as a matter of urgency and in time for WRC-03, studies to determine whether the power flux-density limits included in Table S21-4 adequately protect the fixed service in the bands 37.5-40 GHz and 42-42.5 GHz from FSS and MSS space-to-Earth transmissions;

2 taking into account the resolves, to conduct as a matter of urgency and in time for WRC-03, studies to determine whether the power flux-density limits included in Table S21-4 adequately protect the fixed service in the band 40.5-42 GHz from FSS space-to-Earth transmissions, taking into account the requirements of the FSS and recognizing c);

3 to study technical and operational characteristics and power flux-density values for the BSS in the range 40.5-42.5 GHz;

4 in conducting studies under invites ITU-R 1, 2 and 3 above, to take into account the need to ensure a proper balance in terms of the impact on both the fixed service and space services sharing the same band;

5 to conduct, as a matter of urgency and taking into account the considering paragraphs above, studies on mitigation techniques to improve sharing conditions between the space services referred to under considering above and fixed service systems, taking account of the impact on both the systems of these space services and the fixed service systems;

6 to undertake, as a matter of urgency, studies on the appropriate criteria and techniques for addressing interference from transmitters of the fixed service into earth station receivers in high-density applications in the FSS having allocations in the bands 39.5-40 GHz and 40.5-42 GHz and intended for operation in the same geographic area;

7 in the bands 37.5-40 GHz and 42-42.5 GHz, to study the nominal clear-sky power flux-density levels, and the percentage of time during which they may be exceeded to overcome fading conditions between the satellite and one or more geographically separated earth stations, in order to protect the fixed service while permitting operation of FSS earth stations using, for example, coordinated large antennas, taking into account the balance of constraints on both FSS systems and the fixed service;

8 to report on the results of these studies in time for WRC-03,

that WRC-03 take appropriate action based on the results of these studies.

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