1、 Report ITU-R SA.2162(09/2009)Sharing conditions between space research service extra vehicular activities (EVA)links and fixed and mobile service linksin the 410-420 MHz bandSA SeriesSpace applications and meteorologyii Rep. ITU-R SA.2162 Foreword The role of the Radiocommunication Sector is to ens
2、ure 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 of
3、 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 i
4、n 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 pa
5、tent information database can also be found. Series of ITU-R Reports (Also available online at http:/www.itu.int/publ/R-REP/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (televisi
6、on) 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 fixed servic
7、e systems SM Spectrum management Note: This ITU-R Report was approved in English by the Study Group under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2010 ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without wr
8、itten permission of ITU. Rep. ITU-R SA.2162 1 REPORT ITU-R SA.2162 Sharing conditions between space research service extra vehicular activities (EVA) links and fixed and mobile service links in the 410-420 MHz band (2010) TABLE OF CONTENTS Page 1 Introduction 2 2 Space research service objectives an
9、d requirements 2 3 System description and characteristics. 2 4 Interference to fixed and mobile service links from space research service EVA links 4 5 Interference to space research service EVA links from fixed and mobile service stations 7 5.1 Achievable operational distance . 11 6 Conclusion 12 2
10、 Rep. ITU-R SA.2162 1 Introduction At the World Administrative Radio Conference for dealing with frequency allocations in Certain Parts of the Spectrum (WARC-92) (Malaga-Torremolinos, 1992), a secondary allocation was made to the space research service in the 410-420 MHz band for space-to-space oper
11、ations. These operations, limited to 5 km from an orbiting manned space vehicle, are to permit EVA communications between astronauts and between astronauts and primary or base space vehicles. As permanent space facilities are developed in the future, the needs and requirements for EVA will also incr
12、ease in order to support many of the planned and envisioned space activities. This is particularly true when considering the construction, maintenance, and operation of space facilities. This Report contains update to the work done at (CCIR, 1991). It shows the EVA communication requirements in the
13、410-420 MHz band and identifies typical communication characteristics for the fixed and mobile services in the band. The Report contains the interference investigation/analysis from the space research EVA systems to the fixed and mobile service systems in terms of power flux-densities incident at th
14、e surface of the Earth. A representative fixed service system and a representative mobile service system are used in evaluating interference to the space research EVA links. The power flux-density (pfd) levels in this Report under 4 (called new proposed PFD limits) are those in No. 5.268 in the Radi
15、o Regulations (RR). 2 Space research service objectives and requirements The primary purpose for the space research space-to-space links in the 410-420 MHz band is to provide high quality communication links for astronauts who have exited a space vehicle and are engaged in extra-vehicular activity.
16、These links serve to provide the following three necessary communication requirements: a direct means of voice communication between astronauts engaged in EVA operations; a direct means of voice communication between an astronaut and the primary space vehicle; a direct means of data communication fr
17、om an astronaut to the primary space vehicle. Astronauts communicate via an EVA mobility unit (EMU) attached to the astronauts life support suit. Although communications may be required infrequently, the need for establishing the link must be available at any time. A maximum of four astronauts will
18、be able to communicate simultaneously with the primary space vehicle. Typical orbital altitudes for EVA activities range from 333 km to 460 km with inclination angles of up to 60. Maximum operational distance for communications between astronauts is 500 m. For communications between an astronaut and
19、 primary space vehicle, the maximum operational distance is 1 000 m. 3 System description and characteristics The required communications in this system results in the following three links: links between two (or more) astronauts (EMU-to-EMU); links from an astronaut to the base vehicle (EMU-to-base
20、); links from the base vehicle to one (or more) astronauts (base-to-EMU). Table 1 lists the communication characteristics and Table 2 shows the link equations for this system. Antenna radiation pattern diagrams for the EMU antenna and the base vehicle antenna are given in Figs. 1 and 2. Rep. ITU-R S
21、A.2162 3 TABLE 1 EVA system characteristics Frequency (MHz) 415 Modulation TDMA/CPFSK Burst data rate (kbit/s) 695 Bandwidth (kHz) 800 Required bit error rate 1 105Required Eb/N0(dB) 12.6 EMU Base vehicle Transmitter parameters: Transmitter power (dBW) 6.0 6.0 Transmitter line losses (dB) 0.2 7.0 Ma
22、ximum antenna gain (dBi) 1.5 3.0 Minimum antenna gain (dBi) 10.0 6.0 Antenna polarization Linear Circular Maximum e.i.r.p. (dBW) 4.7 10.0 Receiver parameters: Maximum antenna gain (dBi) 1.5 3.0 Minimum antenna gain (dBi) 10.0 6.0 Antenna cable loss (dB) 0.2 7.0 System noise temperature (K) 1 820 2 7
23、54 TABLE 2 EVA system link budgets EMU-to-EMU EMU-to-base Base-to-EMU Transmitting system: Transmitter power (dBW) 6.0 6.0 6.0 Transmitter line losses (dB) 0.2 0.2 7.0 Minimum antenna gain (dBi) 10.0 10.0 6.0 E.i.r.p. (dBW) 16.2 16.2 19.0 Maximum distance (m) 500 1 000 1 000 Space loss (dB) 78.8 84.
24、8 84.8 Receiving system: Minimum antenna gain (dBi) 10.0 6.0 10.0 Antenna cable losses (dB) 0.2 7.0 0.2 Polarization loss (dB) 3.0 3.0 3.0 Received power (dBW) 108.2 117.0 117.0 System noise temperature (K) 1 820 2 754 1 820 Noise spectral density (dB(W/Hz) 196.0 194.2 196.0 Bit rate bandwidth (dB(H
25、z) 58.4 58.4 58.4 Implementation loss (dB) 3.0 3.0 3.0 Received Eb/N0(dB) 26.4 15.8 17.6 Required Eb/N0(dB) 12.6 12.6 12.6 Link margin (dB) 13.8 3.2 5.0 4 Rep. ITU-R SA.2162 FIGURE 1 EMU antenna pattern Report 2162-01FIGURE 2 Base vehicle antenna pattern Report 2162-024 Interference to fixed and mob
26、ile service links from space research service EVA links Report ITU-R M.358 Protection ratios and minimum field strengths required in the mobile services, specifies that a degradation of the initial S/N of 20 dB to a S/(N + I) of 14 dB is an acceptable protection ratio. This 6 dB of degradation equat
27、es to a S/I of 15.26 dB. This criterion was used to determine the allowed unwanted field strength and corresponding pfd values from EVA links to protect terrestrial mobile receiving stations. At a 0 elevation angle, an unwanted field strength of 1.4 dB(V/m) in a 16 kHz band, corresponding to a pfd o
28、f 153.2 dB(W/(m2 4 kHz) was determined for a base station. For a mobile station, an unwanted field strength of +1.6 dB(V/m) in a 16 kHz band, corresponding to a pfd of 150.2 dB(W/(m2 4 kHz) was determined. Rep. ITU-R SA.2162 5 Curves B, C, D, and E of Fig. 3 show values of worst-case unwanted field
29、strength (expressed in terms of pfds incident at the mobile receiving station) as a function of the angle of elevation of the satellite, taking into account the change in receiving antenna gain with increasing elevation angles. An interfering field strength less than (to the left of) the values give
30、n by the curves would meet the criteria. Curve A of Fig. 3 shows the pfd limits developed by the (CCIR, 1991). As can be seen from the figure, the interfering field strength meets the criteria at most points, and is marginal for the worst-case elevation angles. FIGURE 3 Power flux density (PFD) inci
31、dent at mobile receiving station Report 2162-03ABEDC30Curves A: highest PFD produced at the Earths surface by EVA links (333 km orbital altitude)B: maximum PFD to meet Report ITU-R M.358 criteria, 5 dBi base station antennaC: maximum PFD to meet Report ITU-R M.358 criteria, 12 dBi base station anten
32、naD: maximum PFD to meet Report ITU-R M.358 criteria, 1/4 wave vehicle antennaE: maximum PFD to meet Report ITU-R M.358 criteria, 5 dBi vehicle antennaPFD (dB(W/(m 4 kHz)2 6 Rep. ITU-R SA.2162 The sharing situation between EVA transmitters and terrestrial fixed systems is similar to that involving m
33、obile base stations using 12 dBi antennas. Typical fixed systems have 25 W transmitters and use 10 dBi gain antennas with maximum gains pointed towards the horizon. The current technology allows for more restriction on the EVA system thus allowing for more protection for the fixed and mobile service
34、s in the band. Figure 4 shows the recommended limits agreed to by the (CCIR, 1991), the proposed new recommended limits and the maximum pfd incident at the surface of the Earth produced by the EVA system. FIGURE 4 Recommended power flux density (PFD) limits Report 2162-04CCIR, 1991Proposed limitsMax
35、imum produced by EVACCIR, 1991 recommended PFD limits: 153 dB(W/m ) in any 4 kHz band 0 5 153 + 0.108 ( 5) dB(W/m ) in any 4 kHz band 5 70 146 dB(W/m ) in any 4 kHz band 70 90New proposed PFD limits: 153 dB(W/m ) in any 4 kHz band 0 5 153 + 0.077( 5) dB(W/m ) in any 4 kHz band 5 70 148 dB(W/m ) in a
36、ny 4 kHz band 70 90222222 1451501551601650 20406080Elevation angle, (degrees)PFD(dB(W/(m4 kHz)2 Rep. ITU-R SA.2162 7 5 Interference to space research service EVA links from fixed and mobile service stations In considering interference to EVA links, two assumptions are required regarding the developm
37、ent of a set of representative transmission characteristics and a worldwide distribution of mobile service stations. An explanation of these assumptions is given below: Characteristics of representative mobile emitters Characteristics of mobile systems in the 410-420 MHz band were based on data from
38、 the International Frequency List (IFL) and usage in the United States of America. Characteristics of typical base and mobile stations are as follows: Base Mobile Power (W) 100.0 100.0 Power (dBW) 20.0 20.0 Maximum gain (dB) 12.0 or 5.0 5.0 Bandwidth (kHz) 16.0 16.0 In some parts of the world, lower
39、 powers may be typically used. Figure 5 shows four antenna patterns typically used in the mobile service: a 12 dBi base station antenna, a 5 dBi base station antenna, a quarter-wave dipole vehicle antenna, and a 5 dBi vehicle antenna. For this analysis, the population of mobile transmissions is assu
40、med to be made up of the following mix of antennas, using the transmitter power levels given above. 25% are base stations, using the 12 dBi base station antenna pattern (see Fig. 5a); 25% are base stations, using the 5 dBi base station antenna pattern (see Fig. 5b); 25% are mobile stations, using th
41、e quarter-wave dipole antenna pattern (see Fig. 5c); 25% are mobile stations, using the 5 dBi mobile station antenna pattern (see Fig. 5d). Line losses, although assumed to be zero in this analysis, would typically reduce the e.i.r.p. by 3 dB. The number and distribution of simultaneous emitters The
42、 extent to which the 410-420 MHz band is used throughout the world by the mobile services can only be roughly estimated since there is no international requirement to register all the systems in the band. For the purpose of this analysis, it was therefore necessary to assume some sort of a worldwide
43、 distribution of these systems. This distribution was based on the following considerations: the identification of the 479 largest cities in the world. These are shown in Fig. 6; mobile systems will be used mainly in and around these large cities; based on United States statistics, one terrestrial s
44、tation per 6 224 people is assumed for the most populated cities in the world; for areas outside large cities: for every country where the number of telephones per capita exceeded 1% of the United States rate (from a 1990 World Almanac), the country was divided into approximately 100 km2. Each of th
45、ese squares represents the location of 33 terrestrial stations. The locations of these rural areas are shown in Fig. 7; it is assumed that each mobile station operates with a 20% duty cycle. 8 Rep. ITU-R SA.2162 FIGURE 5 Mobile system antenna pattern Report 2162-05806040200 20 15 10 5 0 5 10 1580604
46、0200 20 15 10 5 0 5 10 15806040200 20 15 10 5 0 5 10 15806040200 20 15 10 5 0 5 10 15c) Quarter-wave dipole vehicle antenna gain (dBi) d) TAE 60620A vehicle antenna gain (dBi)a) Base antenna gain (dBi) b) Base antenna gain (dBi)Rep. ITU-R SA.2162 9 FIGURE6 Most populated cities in the world Report 2
47、162-06 180 150 120 90 60 30 0 30 60 90 120 150 180 90 60 300306090West EastSouthNorthFIGURE 7 Rural areas used in the interference model Report 2162-07 180 150 120 90 60 30 0 30 60 90 120 150 180 90 60 300306090West EastSouthNorth10 Rep. ITU-R SA.2162 Using the distribution model described above, th
48、e interfering power level produced at orbital altitudes of 333 km and 460 km and an inclination of 60 was calculated for every point on the orbit. Interference was calculated as the power level in dB(W/MHz) that would be received by an isotropic antenna. The highest interference level obtained was 9
49、1.7 dB(W/MHz) incident at the satellite at an altitude of 333 km. Figure 8 shows the interference level versus percentage of time for the simulations. The received interference levels were the greatest over the United States of America and Europe. A map depicting the locations on the EVA orbit where the interference level was the greate
