1、 Rec. ITU-R M.1184-2 1 RECOMMENDATION ITU-R M.1184-2 Technical characteristics of mobile satellite systems in the frequency bands below 3 GHz for use in developing criteria for sharing between the mobile-satellite service (MSS) and other services (Question ITU-R 201/8) (1995-2000-2003) The ITU Radio
2、communication Assembly, considering a) that Resolution 214 (Rev.WRC-97) resolves that further studies are urgently required on operational and technical means to facilitate sharing between the non-GSO MSS and other radiocommunication services having allocations and operating below 1 GHz; b) that, wh
3、ile some MSS system parameters are still under development, a summary of representative technical characteristics of MSS systems is useful for conducting sharing studies and for development of appropriate sharing criteria by the ITU-R; c) that MSS system designs will evolve and new MSS systems may b
4、e proposed and therefore representative characteristics should be maintained as an on-going activity, noting a) that the necessary frequency sharing studies require the involvement of several Radiocommunication Study Groups; b) that the technical parameters in this Recommendation are referenced and
5、used in several other ITU-R Recommendations; c) that MSS networks and the associated lists of the technical parameters in this Recommendation have been chosen specifically for use in modelling frequency sharing and interference, recommends 1 that the representative technical characteristics for non-
6、GSO MSS systems, as given in Annexes 1 and 2, be used by the ITU-R in conducting sharing studies and in the development of Recommendations on sharing criteria for non-GSO MSS systems; 2 that the representative technical characteristics for geostationary MSS systems given in Annexes 1 and 2 be used f
7、or conducting sharing studies and in the development of ITU-R Recommendations on sharing criteria for geostationary MSS systems; 3 that the characteristics given in Annexes 1 and 2 be updated periodically to reflect changes in the MSS example system designs and to incorporate new MSS system examples
8、 as they are proposed and as their designs mature. 2 Rec. ITU-R M.1184-2 Annex 1 Characteristics of representative 1-3 GHz MSS networks 1 Satellite orbits Currently, the GSO is being used for the MSS. Some proposed mobile-satellite systems plan to use non-GSO orbits. Suitable orbits are determined b
9、y coverage requirements, service considerations and frequency sharing, as well as other considerations. 2 Global and regional/national GSO systems Current Inmarsat and Russian Volna satellites utilize Earth-coverage antennas to provide near-global coverage from the GSO. The Russian systems are simil
10、ar to those of Inmarsat systems, the characteristics of which are presented in Table 2. Several administrations are implementing regional/national GSO mobile-satellite systems to provide aeronautical, land and maritime services at 1.6/1.5 GHz. In addition to the above systems at 1.6/1.5 GHz, Japan i
11、s planning to put into operation a GSO mobile-satellite system in the 2.6/2.5 GHz bands. The future generation of Inmarsat and Russian satellites and the planned regional and national systems will use spot beam to provide greater spectrum efficiency and conserve transmitted power of the satellite an
12、d mobile earth station. 2.1 Maritime mobile-satellite service The Inmarsat-B system provides a power and bandwidth efficient replacement for the original Inmarsat-A and provides voice, facsimile, data and telex services. In parallel with Inmarsat-B, Inmarsat-M uses lower symbol transmission rates fo
13、r voice, data and facsimile requirements for smaller ships. The Inmarsat-C system provides store and forward data and telex using small, low cost equipment. 2.2 Aeronautical mobile-satellite service The International Civil Aviation Organization (ICAO) Standards and Recommended Practices (SARPs) for
14、aeronautical mobile-satellite (R) service (AMS(R)S), airborne equipment have been published in Annex 10 to the Convention on International Civil Aviation. The SARPs include a requirement for priority and pre-emption for safety communications over all other communications. All systems providing AMS(R
15、)S services to the international civil aviation community have to conform with the applicable ICAO SARPs. In summary, the aeronautical satellite communication systems will have to take into account the priority needs for safe operation of aircraft and the avionics will have to satisfy the severe req
16、uirements of aircraft environments. Rec. ITU-R M.1184-2 3 2.3 Land mobile-satellite service The land mobile-satellite service (LMSS) has proven to be an effective means for providing dependable communications in remote and sparsely populated areas, either as extensions of terrestrial VHF and UHF net
17、works or as replacements for HF networks. Worldwide roaming capability is a mandatory function of International Mobile Telecommunications-2000 (IMT-2000) and the satellite component defined in Recommendations ITU-R M.687 and ITU-R M.818 is one of the important components that encourage the IMT-2000
18、capability. The interworking of the mobile-satellite system with the terrestrial system can encourage user convenience within not only IMT-2000 but also general LMSS. 2.4 Distress and safety service Technical and operating characteristics of the Inmarsat 1.6 GHz satellite EPIRB system are described
19、in Recommendation ITU-R M.632. Tables 1 to 3 present representative technical characteristics of service links for selected MSS networks that utilize space stations in GSOs. TABLE 1a Technical characteristics of GSO mobile-satellite systems (service return link) GSO System Parameter A B C D E F Pola
20、rization Feeder link Linear Linear Linear Linear Circular Linear Service link RHCP RHCP RHCP RHCP RHCP Circular Direction of transmission Earth-to-space Earth-to-space Earth-to-space Earth-to-space Earth-to-space Earth-to-space Frequency bands Feeder link (GHz) 5 12 11 11 4 4, 11, 12 Service link (G
21、Hz) 1.6 1.6 1.6 2.0 2.0 1.6 Orbit Altitude (km) 36 000 36 000 36 000 36 000 36 000 36 000 Satellite separation (degrees) 120 78 Not applicableNot applicable* Not applicable Number of satellites 3 2 1 1 4 to 6 1 or 2 Orbital planes Not applicableNot applicableNot applicableNot applicableNot applicabl
22、e Not applicable Inclination angle Not applicableNot applicableNot applicableNot applicableNot applicable Not applicable Satellite antennas Number of beams (service link) 180 50 7 28 250 Over 200 Beam size (degrees) 1 1 6 2 * 0.7 4 Rec. ITU-R M.1184-2 TABLE 1a (end) GSO System Parameter A B C D E F
23、Satellite antennas (cont.) Satellite coverage area Global Regional North America,Alaska, Hawaii North America,Alaska, Hawaii Global Regional Average beam side lobes (dB) * 25 25 25 * 20 Beam frequency reuse 5 5 1.3 2 * 1 to 30 Link characteristics Nominal user e.i.r.p. (dBW) 6 0.5 12.5 10.9 1 to +8
24、7.5 to 3.5EOC satellite G/T (dB(K1) 10 11 3.0 9.8 11 15.7 Transmission parameters Modulation QPSK QPSK QPSK QPSK QPSK QPSK Coding FEC FEC * * FEC FEC Access scheme CDMA FDMA FDMA FDMA FDMA/ TDMA FDMA/ TDMA Duplex scheme * FDD FDD FDD FDD FDD Frame length Not applicableNot applicableNot applicableNot
25、 applicable* 40 Burst rate (kbit/s) Not applicableNot applicableNot applicableNot applicable32 46.8 Chip rate (Mchip/s) 8.33 Not applicableNot applicableNot applicableNot applicable Not applicableVoice activity factor 0.4 0.4 0.4 0.4 0.4 0.4 RF carrier spacing (MHz) * 0.006 0.006 0.006 * 0.03125 RF
26、channel spacing (MHz) * 0.006 0.006 0.006 * 0.03125 Modulation bandwidth (MHz) * 0.0045 0.0047 0.0047 * 0.0234 Required Eb /N0(dB) Voice 2.5 9.0 9.0 9.0 4.0 3.5 Data 4.1 9.0 9.0 9.0 * 5.5 to 7.0 Maximum MES antenna discrimination towards the horizon (dBi) * 7 7 7 1.0 7 to 19 NOTE 1 See the legend fo
27、r special terms and symbols at the end of Table 4. Rec. ITU-R M.1184-2 5 TABLE 1b Technical characteristics of GSO mobile-satellite systems (service forward link) GSO System Parameter A B C D E F Polarization Feeder link Linear Linear * * Circular Linear Service link RHCP RHCP * * RHCP Circular Dire
28、ction of transmission Space-to-Earth Space-to-Earth Space-to-Earth Space-to-Earth Space-to-Earth Space-to-Earth Frequency bands Feeder link (GHz) 6 14 13 13 6 6, 13, 14 Service (GHz) 2.5 1.5 1.5 1.9 2.2 1.5 Orbit Altitude (km) 36 000 36 000 36 000 36 000 36 000 36 000 Satellite separation (degrees)
29、120 78 Not applicable Not applicable* Not applicableNumber of satellites 3 2 1 1 4 to 6 1 or 2 Orbital planes Not applicableNot applicableNot applicable Not applicableNot applicable Not applicableInclination angle Not applicableNot applicableNot applicable Not applicableNot applicable Not applicable
30、Satellite antennas Number of beams (service link) 180 50 7 28 150 Over 200 Beam size (degrees) 1 1 * * * 0.7 Satellite coverage area Global Regional North America,Alaska, Hawaii North America,Alaska, Hawaii Global Regional Average beam side lobes (dB) * 25 25 25 * 20 Beam frequency reuse 5 5 1.2 2 *
31、 1 to 30 Link characteristics Maximum e.i.r.p./beam (dBW) 45.8 53.5 58.4 52.8 * * Average gain/beam (dBi) * 44 32 41.1 * 44.5 e.i.r.p./carrier (dBW) 28.8 30 30 35.5 42 24.5 to 45.0e.i.r.p./shadowed user (dBW) * 30 30 35.5 * * 6 Rec. ITU-R M.1184-2 TABLE 1b (end) GSO System Parameter A B C D E F Link
32、 characteristics (cont.) e.i.r.p./unshadowed user (dBW) * 30 30 35.5 * * e.i.r.p./CDMA channel (dBW) Not applicableNot applicableNot applicableNot applicableNot applicable Not applicablepfd level per beam carrier (dB(W/(m2 4 kHz) * 131 131.0 127.5 123.0 138.0 to117.5 Transmission parameters Number o
33、f channels/satellite * 5 000 2 000 10 000 5 000 20 000 User G/T (dB(K1) 20 22 16 16 23 23.5 to 9.0 Minimum elevation angle (degrees) 5 5 5 5 10 20 Lifetime (years) 12 12 12 12 10 to 12 12 Modulation QPSK QPSK QPSK QPSK QPSK QPSK Coding FEC FEC FEC FEC FEC FEC Access scheme CDMA FDMA/ TDMA FDMA FDMA
34、TDMA FDMA/ TDMA Frame length (ms) * Not applicableNot applicableNot applicable* 40 Burst rate (kbit/s) Not applicableNot applicableNot applicableNot applicable32 46.8 Chip rate (Mchip/s) 8.33 Not applicableNot applicableNot applicable* Not applicableVoice activity factor 0.4 0.4 0.4 0.4 0.4 0.5 Requ
35、ired Eb/ N0(dB) Voice 2.5 9 9 9 * 3.5 Data 4.1 9 9 9 * 5.5 to 7.0 MES geographical distribution * * * * * * Maximum permissible levels of interference power * * * * * * NOTE 1 See the legend for special terms and symbols at the end of Table 4. Rec. ITU-R M.1184-27TABLE 2 Inmarsat GSO systems overvie
36、w Aeronautical A B C M Mini-M GAN PMC High gain High gain Service MMSS LMSS MMSS LMSS MMSS LMSS MMSS LMSS LMSS LMSS LMSS AMSS AMS(R)S AMSS AMS(R)S Typical mobile station antenna gain (dBi) 21 21 0 14 12 10 18 16.5 12 0 Antenna type (example) Dish Dish Quad helix Short backfire Linear array Phased ar
37、ray Phased array Phased array Phased array Quad helix Typical antenna size 1 m diameter 1 m diameter 5 cm diameter 40 25 cm 60 9 cm 30 20 cm 65 45 cm 50 35 cm 2 panels 60 60 cm 20 15 cm Mobile earth station figure of merit (G/T) (dB(K1) 4 4 23 10 12 17 7 9 12 26 Mobile earth station e.i.r.p./channel
38、 (dBW) 36 33 11 27 25 14 28 21 26 12 User data rate 9.6 kbit/s 9.6 kbit/s 600 bit/s 2 400 bit/s 2 400 bit/s 2 400 bit/s 64 kbit/s 432 kbit/s 9.6 kbit/s 300 bit/s Communication channel rate and modulation FM, 12 kHz deviation (voice) 24 kbit/s, OQPSK (voice) 600 bit/s, BPSK 8 kbit/s, OQPSK 8 kbit/s,
39、OQPSK 5.6 kbit/s OQPSK 65.2 kbit/s 16-QAM 732 kbit/s 16-QAM 21 kbit/s, OQPSK 600 bit/s, BPSK Typical C/N0for communication channel (dB(Hz) 53 47 32 42 42 41 53 65 44 32 Satellite e.i.r.p./channel (dBW) 17.5 16 20 17 17 24 27 44 22 22 Channel spacing (nominal) (kHz) 50 20 5 10 10 13 60 200 17.5 2.5 S
40、atellite peak antenna gain(1)(dBi) 18 18 18 18 18 27 27 41 18 18 pfd (1)Nominal value for first and second generation satellites. NOTE 1 See the legend for special terms and symbols at the end of Table 4. 8 Rec. ITU-R M.1184-2 TABLE 3 National/regional GSO system overview Japan Australia Canada/ Uni
41、ted States of America N-STAR(1)Service MSS MSS LMSS/ MMSS Typical mobile station antenna gain (dBi) 12 8 to 13 0 to 4 To be determined Antenna type (example) To be determined Electrically scanned phased array Mast type To be determined Typical antenna size To be determined 25 to 50 cm diameter To be
42、 determined Mobile earth station figure of merit (G/T) (dB(K1) 13 15 to 12 23 to 18 To be determined Mobile earth station e.i.r.p./channel (dBW) 15 10 to 16 To be determined User data rate 2 400 bit/s 2.4 to 4.8 kbit/s 4 to 8 kbit/s, voice To be determined Communication channel rate and modulation 6
43、.6 kbit/s 4.8 to 9.6 kbit/s, OQPSK TCM /4 shifted QPSK Typical C/N0for communication channel (dB(Hz) 48 45 to 51 To be determined Satellite e.i.r.p./channel (dBW) 22 23 to 29 52(2)Channel spacing (nominal) (kHz) 7.5 5 to 10 12.5 Satellite peak antenna gain(1)(dBi) To be determined 32 34 pfd * * * (1
44、)N-STAR uses the 2.5/2.6 GHz band, whereas the other systems in this Table use the 1.5/1.6 GHz band. (2)Total satellite e.i.r.p. NOTE 1 See the legend for special terms and symbols at the end of Table 4. Rec. ITU-R M.1184-2 9 3 Non-GSO MSS system characteristics Proposed personal communication syste
45、ms using non-GSO satellites, including satellites using low, medium and intermediate orbits, are expected to provide voice, data communications and positioning on a worldwide basis using mobile terminals or hand-held portable terminals using omnidirectional antennas. Operation in a band contiguous w
46、ith future land mobile communication systems would permit interoperability between non-GSO MSS and land mobile systems. Table 4 presents representative technical characteristics of service links for selected MSS networks that utilize space stations in non-GSOs. 4 Propagation factors and mobile anten
47、na characteristics Signal level variation due to multipath effects and blockage by ships superstructure occurs in MMSS links. Multipath, especially sea surface-reflected multipath, is a significant factor to be considered in the design of an aeronautical mobile-satellite system. In LMSS links, folia
48、ge shadowing is a significant additional effect which increases with frequency. Furthermore, several propagation factors should be taken into account when designing a non-GSO MSS system providing personal services. These propagation factors affect system characteristics, such as link margin and tran
49、smission power control techniques. Reference radiation patterns for various types of LMSS mobile earth station antenna are recommended to assess the interference calculation for coordination studies (see Recommendation ITU-R M.1091). 10 Rec. ITU-R M.1184-2TABLE 4a Technical characteristics of non-GSO mobile-satellite systems (service return link) G System Parameter A(1)B C D E F Link 1 Link 2 H R Polarization Feeder link RHCP RHCP Circular RHCP/ LHCP RHCP/LHCP Circular RHCP RHCP LHCP Circular Ser
