1、 Recommendation ITU-R SA.1626-1(12/2013)Feasibility of sharing between the space research service (space-to-Earth)and the fixed and mobile services in the band 14.8-15.35 GHzSA SeriesSpace applications and meteorologyii Rec. ITU-R SA.1626-1 Foreword The role of the Radiocommunication Sector is to en
2、sure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions o
3、f the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced
4、in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R p
5、atent information database can also be found. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service
6、(television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fix
7、ed service systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2014 I
8、TU 2014 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R SA.1626-1 1 RECOMMENDATION ITU-R SA.1626-1*Feasibility of sharing between the space research service (space-to-Earth) and the fixed and mobile services i
9、n the band 14.8-15.35 GHz (2003-2013) Scope This Recommendation provides the characteristics of space research systems and the results of analysis on feasibility of sharing between the space research service (space-to-Earth) and the fixed and mobile services in the band 14.8-15.35 GHz. The ITU Radio
10、communication Assembly, considering a) that in the band 14.8-15.35 GHz, the fixed and mobile services are allocated on a primary basis, the space research service (SRS) is allocated on a secondary basis; b) that the SRS (passive) and Earth exploration-satellite service (EESS) (passive) are allocated
11、 on a secondary basis by No. 5.339 of the Radio Regulations (RR), Edition of 2012 in the 15.20-15.35 GHz band; c) that requirements exist for wideband SRS downlinks to transmit future high data rate scientific data; d) that under favourable conditions the required separation distances between receiv
12、ing SRS earth stations and transmitting fixed stations are relatively small (under 30 km) and under less favourable conditions may be relatively large (up to 200 km); e) that separation distances may decrease significantly due to frequency channelization, natural site shielding, terrain clutter, and
13、 other terrain features, noting a) that due to the small number of expected SRS earth stations to be deployed worldwide (10-40 stations), coordination between fixed and land mobile systems and the SRS stations would not put undue constraints on either of the services, recommends 1 that sharing betwe
14、en a GSO SRS satellite transmitting in the space-to-Earth direction and a receiving GSO data relay satellite (DRS) operating near 15 GHz is feasible if the satellites are separated by 12 km (equivalent to an orbital separation of 0.02) or more; 2 that, when designing SRS systems, the probability of
15、receiving brief periods of interference from DRS user satellites should be taken into account. This interference should exist for less than 0.1% of the time; 3 that GSO SRS systems operate within the following pfd limits at the Earths surface under assumed free space propagation conditions in the ba
16、nd 14.8-15.35 GHz: *This Recommendation should be brought to the attention of Radiocommunication Study Groups 8 and 9. 2 Rec. ITU-R SA.1626-1 4 that non-GSO SRS systems operate within the following pfd limits at the Earths surface under assumed free space propagation conditions in the band 14.8-15.3
17、5 GHz: 5 that separation distances required by SRS receiving earth stations for protection from fixed and mobile transmitting stations may be derived using the methodology outlined in Annex 1 and the protection criterion for space-to-Earth SRS links contained in Recommendation ITU-R SA.609; 6 that s
18、uitable measures related to the deployment of SRS earth stations may need to be identified in order not to constrain the use of the band 14.8-15.35 GHz by the fixed service. Annex 1 Feasibility of sharing between the SRS (space-to-Earth) and the fixed and mobile services in the band 14.8-15.35 GHz 1
19、 Introduction International space agencies are currently planning on implementing high data rate space research missions with bandwidth requirements up to 400 MHz. Satellites for these missions will carry telescopes and/or other passive instruments to measure phenomenon such as the Earths magnetosph
20、ere and solar flares. In the 2012 Edition of the Radio Regulations, 8 450-8 500 MHz is the only band below the 37-38 GHz band that is available on a primary basis in the SRS to transmit moderate to high-rate data directly from Earth orbiting satellites to earth stations. Since this band will not mee
21、t the requirements of future high rate space research missions, a new primary allocation is needed. The current allocations in the band 14.8-15.35 GHz (Radio Regulations, Edition of 2012) are shown in Table 1. They include primary allocations to the fixed and mobile services and a secondary allocati
22、on to the SRS. In addition, RR No. 5.339 allocates the 15.20-15.35 GHz segment of the band to the SRS (passive) and the EESS (passive) on a secondary basis. Limit (dB(W/m2) in 1 MHz bandwidth for angle of arrival, , above the horizontal plane 0-5 5-25 25-90 126 126 + 0.5( 5) 116 Limit (dB(W/m2) in 1
23、 MHz bandwidth for angle of arrival, , above the horizontal plane 0-5 5-25 25-90 124 124 + 0.5( 5) 114 Rec. ITU-R SA.1626-1 3 TABLE 1 Allocations in the band 14.8-15.35 GHz (from the Radio Regulations, Edition of 2012) Based on these allocations, establishment of a primary SRS allocation in this ban
24、d requires the consideration of a variety of interference scenarios, as detailed in Table 2. An analysis of these environments to facilitate the identification of appropriate sharing conditions has been performed and is documented herein. Section 2 provides information on the SRS system characterist
25、ics used for this analysis. Section 3 provides example fixed service system characteristics for the 14.8-15.35 GHz band. Section 4 provides the key characteristics of the DRS system operating in this band. The criteria for protection of fixed service or mobile service stations from SRS emissions are
26、 derived in Section 5. Section 6 addresses interference to SRS receiving earth stations from fixed or mobile service transmissions. Section 7 derives sharing conditions for SRS (space-to-Earth) and receiving DRS operations. Protection of SRS (passive) and EESS (passive) links is not addressed at thi
27、s time as none of these systems are known to exist in this band. TABLE 2 Applicable interference scenarios Allocation to services Region 1 Region 2 Region 3 14.8-15.35 FIXED MOBILE Space research 5.339 5.339 The bands 1 370-1 400 MHz, 2 640-2 655 MHz, 4 950-4 990 MHz and 15.20-15.35 GHz are also all
28、ocated to the space research (passive) and Earth exploration-satellite (passive) services on a secondary basis. Interferer Victim Comments SRS (space-to-Earth) Low-orbiting satellite GSO satellite Receiving fixed/mobile service station Line-of-sight propagation assumed Transmitting fixed/mobile serv
29、ice station SRS receiving earth station Separation distances determined using the methods of Recommendation ITU-R SM.1448 assuming mode (1) propagation over an inland great-circle path (zone A2) SRS (space-to-Earth) Low-orbiting satellite GSO satellite Receiving DRS Adjacent Near antipodal Line-of-s
30、ight propagation assumed SRS (space-to-Earth) Low-orbiting satellite GSO satellite SRS/EESS (passive) No known use of the 15.20-15.35 GHz band under the provisions of RR No. 5.339 4 Rec. ITU-R SA.1626-1 2 Characteristics of future high-rate SRS missions These missions will be limited in number with
31、an estimated three to five satellites per year worldwide, and will generally be either in a low-polar orbit or in an equatorial orbit with some at geostationary altitudes and others at the L1 or L2 libration points. The characteristics of the GSO and low-orbiting SRS satellites transmitting in the s
32、pace-to-Earth direction are reflected in the link budgets given in Table 3. The links were assumed to support a data rate of 400 Mbit/s on the space-to-Earth link. The e.i.r.p. spectral density was adjusted so that the pfd limits of Recommendation ITU-R SA.510 would be satisfied at low elevation ang
33、les. The radiation pattern of the receiving antenna of the SRS earth station was assumed to conform to Recommendation ITU-R SA.509. Sharing feasibility was assessed on the basis of the protection criteria given in Recommendation ITU-R SA.609. TABLE 3 Example high-rate SRS mission link budgets Freque
34、ncy (GHz) 15 15 Satellite altitude (km) 800 35 785 300 000(1)Data rate (Mbit/s) 400 Modulation method QPSK Transmitter power (W) (dBW) 5.0 20.0 7.0 13.0Filter, cable loss (dB) 0.5 Transmitting antenna diameter (m) 0.38 0.86 1.5 Transmitting antenna gain (dBi) 33.0 40.0 45.2 Antenna 3 dB beamwidth (d
35、egrees) 3.68 1.64 1.06 e.i.r.p. (dBW) 39.5 52.5 57.7 Beam-edge allowance (dB) 3.0 4.0(3)Atmosphere and rain loss (dB) Path loss (dB) 183.4 208.1 225.65 Spectral pfd (dB(W/(m2 4 kHz) 146.0 157.6 146.0(2)Receiving antenna gain (dBi) 45.0 55.0 67.0 Receiver noise temperature (K) 100.0 Elevation angle (
36、degrees) 10.0 Antenna noise temperature (K) 50.0 Receiving system temperature (K) 150.0 Modulation filter loss (dB) 0.5 Demodulator loss (dB) 0.5 Mean received Eb/N0(dB) 18.9 17.2 14.8 Theoretical Eb/N0 (BER = 1 106) (dB) 10.5 Required Eb/N0(BER = 1 106) (dB) 11.5 Rec. ITU-R SA.1626-1 5 TABLE 3 (end
37、) Margin (dB) 7.4 5.7 3.3 (1)HEO with apogee 300 000 km, perigee 500 km, minimal distance for data transmit 15 000 km. (2)For minimal distance of data transmit. (3)Sum of Beam-edge allowance (dB) and Atmosphere and rain loss (dB) 3 Characteristics of fixed service systems in the 14.8-15.35 GHz band
38、Examples of typical fixed service system characteristics in the 14.8-15.35 GHz band are shown in Table 4. The parameter values for Systems A and B are taken from Recommendation ITU-R F.758. Systems C and D are typical of many other fixed service systems currently deployed. TABLE 4 Example FS charact
39、eristics for the band 14.8-15.35 GHz 4 Characteristics of the DRS system operating in the 14.8-15.35 GHz band The DRS network consists of several GSO-satellites used to relay signals between centrally located earth stations and low-orbiting user satellites. The DRS network uses frequencies allocated
40、 to the SRS in the 2 GHz and 13-15 GHz bands and bands allocated to the inter-satellite service in the 23/26 GHz bands. The frequency plan for the 14.8-15.35 GHz band segment is shown in Fig. 2. As shown, the DRS receives in this band. Earth-to-space transmissions include a frequency pilot, a multip
41、le access (MA) signal to be retransmitted in the 2 025-2 110 MHz band and a single access (KSA2) signal to be transmitted in a band centred at 13.775 GHz. These Earth-to-space transmissions originate at earth stations located in the United States of America and on the island of Frequency band 14.8-1
42、5.35 GHz Modulation 64-QAM (A) QPSK (B) 4-FSK (C) 4-FSK (D) Capacity (Mbit/s) 140 4 6.3 12.6 Channel spacing (MHz) 28 10.5 5 10 Antenna diameter (m) 2.4 1.8 0.6 1.2 Antenna gain (maximum) (dBi) 49.0 45.0 36.5 42.5 Feeder/multiplexer loss (minimum) (dB) 2 0 2 2 Receiver IF bandwidth (MHz) 40 3.5 5 10
43、 Receiver noise figure (dB) 4 4 5 7 Receiver thermal noise (dBW) 124 136 132 129 Nominal long-term interference (dBW) 134 146 142 139 Spectral density (dB(W/MHz) 150.0 149.8 149.0 149.0 Maximum low arrival angle single entry pfd(1)(dB(W/(m2/MHz) 149.0 147.0 136.0 142.0 (1)pfd = interference spectral
44、 density + feeder loss antenna gain gain (1 m2) +3 dB linear to circular polarization discrimination. 6 Rec. ITU-R SA.1626-1 Guam. Figure 2 also shows that the DRS receives space-to-space transmissions from low-orbiting satellites. These transmissions are centred near 15 GHz and occupy a bandwidth u
45、p to 225 MHz. FIGURE 1 Architecture of a DRS network (Recommendation ITU-R SA.1018) SA.1862-01A: DRSB: DRS earth stationC: DRS user spacecraftD: forward feeder linkE: forward inter-orbit link (IOL)F: return IOLG: return feeder linkCEFABDGFIGURE 2 Frequency utilization of a DRS network in the band 14
46、.8-15.3 GHz SA.1862-0214.8 14.9 15 15.1 15.2 15.3 GHzMA Pilot KSA2Earth-to-space linksSpace-to-space linksKSARec. ITU-R SA.1626-1 7 5 Protection of fixed service/mobile service stations from interference from SRS space stations The interference criterion to protect the fixed service from time varyin
47、g aggregate interference, as would be exhibited by non-GSO SRS satellites, is taken from Recommendation ITU-R F.1494. This Recommendation applies to the band 10.7-12.7 GHz; however, the fixed service applications in the 14.8-15.35 GHz band have quite similar characteristics. Thus, this Recommendatio
48、n could also be applied in this case. Consequently, the non-GSO interference criteria are given as: short term: I/N should not exceed +20 dB (hard limit); long term: The fractional degradation of performance (FDP) should not exceed 10%. For GSO satellites, the following interference criteria are app
49、lied: the route FDP should not exceed 10% in more than 10% of the fixed service routes; and the station I/N should not exceed 10 dB in more than 10% of the fixed service receive stations. Results of simulations of the probabilistic interference from SRS, based on assumed deployment of 24 satellites in GSO orbit, into digital point-to-point fixed service systems show that the pfd limits in the band 10.7-11.7 GHz are necessary to protect the fixed service in the band 14.8-15.35 GHz. These limits are given a
