1、Rec. ITU-R M.1388 1 RECOMMENDATION ITU-R M.1388* THRESHOLD LEVELS TO DETERMINE THE NEED TO COORDINATE SERVICE (SOUND) AND PARTICULAR SYSTEMS IN THE LAND BETWEEN SPACE STATIONS IN THE BROADCASTING-SATELLITE MOBILE SERVICE IN THE BAND 1452-1492 MHz (Question ITU-R 106/8) (1999) Summary Until such time
2、 as additional studies are complete, the power flux-density level specified in this Recommendation may be applied as coordination trigger threshold level to space stations in the broadcasting-satellite service (sound) operating in the frequency band 1 452-1 492 MHz to share this frequency band with
3、particular land mobile systems. The ITU Radiocommunication Assembly, considering a) that WARC-92 allocated the band 1452-1 492 MHz on a primary basis in worldwide basis to the broadcasting- satellite service (sound) (BSS(s), subject to the provisions of the Radio Regulations (RR) Nos. 53.342, S5.343
4、 55.344 and S5.347, and to Resolution 528 (WARC-92); b) that the frequency band in a) is also allocated to the mobile service; cl (LMS) now in operation; that there are a number of common characteristics and parameters among the various land mobile systems d) e) that the protection criteria for LMS
5、 in general is yet to be determined; that the performance objectives for the LMS in general are yet to be determined; f) the BSS(s); that land mobile service stations may receive interference caused by emissions from satellite transmitters in g) Resolution 33 (WARC-79); that this Recommendation does
6、 not negate the ability of administrations to seek coordination under h) in No. S5.348A in the RR in the band 1 492-1 525 MHz; that there is already a coordination threshold between the mobile-satellite service and the land mobile service j) that there are no appropriate coordination threshold level
7、s to protect the land mobile service in .the band 1 452-1 492 MHz; k) that it is difficult to change technical parameters in the existing systems operating in the above band; 1) the BSS(s) to the fixed service may not be appropriate for this purpose; that the coordination threshold specified in Reco
8、mmendation ITU-R F. 1338 dealing with the interference from m) that methods and techniques for effective coordination need to be established, * This Recommendation should be brought to the attention of Radiocommunication Study Group 10. COPYRIGHT International Telecommunications Union/ITU Radiocommu
9、nicationsLicensed by Information Handling Services2 Carrier levei Thermal noise Rec. ITU-R M.1388 dB (“14 kHz) -146.2 dB (W/4 kHz) -1 62.8 recommends Total interference noise Antenna aperture Allowable pfd for inter-service interference 1 that for BSS(s) geostationary space stations, and until such
10、time as further studies related to considerings d) and e) are completed, the following power flux-density (pfd) levels at the surface of the Earth may be applied as the coordination threshold with particular systems in the land mobile service operating in the band 1452 to 1492 MHz (see Notes 1 to 4)
11、 dB (W/4 kHz) -161.7 dB (m2) -22.8 dB (Wlm2/4 kHz) -148.9 -150 dB (W/m2) in 4 kHz for all angles of arrivai (Notes 5 and 6). NOTE 1 -LMS technical parameters based on particular digital systems referred to in recommends 1 are given in Annex 1 to this Recommendation. NOTE 2 - The pfd level set out i
12、n recommends 1 was derived using a deterministic analysis methodology for the mobile station at the service area boundary. NOTE 3 - The use of a probabilistic analysis based on the acceptability of a marginal reduction in service availability within a small percentage of the total service area may l
13、ead to higher coordination trigger thresholds. NOTE 4 - Administrations are encouraged to consider the sharing measures set out in Annex 2 to this Recommendation. In the specific case that coordination is necessary in the band used for repeater station receivers in LMS systems, 0 2.2 of Annex 2 woul
14、d be relevant as the measures described there may enhance the prospect of sharing. NOTE 5 - Analogue LMS systems also operate in the shared band and until such time as sharing studies related to such a use of the LMS band are completed, the pfd trigger threshold in recommends 1 may be provisionally
15、applied. NOTE 6 - The reference bandwidth of 4 kHz may be reviewed in the actual coordination process. ANNEX 1 Technical parameters of particular systems in the land mobile service Table 1 gives technical parameters of a digital system in the land mobile service, which are already operating in the b
16、and 1452 to 1 492 MHz in one country. The value in Table 1 represents the requirements around the edge of each service coverage area. TABLE i COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services - STD-ITU-R RECMN M*L388-ENGL 1799 Li855212
17、0535353 LiAb Rec. ITU-R M.1388 3 ANNEX 2 Measures to facilitate inter-service sharing 1 Interference mitigation techniques For land mobile systems, techniques such as diversity reception, digital modulation and channel coding, and code division multiple access would assist sharing with BSS(S) system
18、s. 2 Implementation measures When interference calculations are being made, worst case scenarios and deterministic methodologies are likely to be used which could tend to lead to the conclusion that co-frequency or co-channel sharing by different services cannot occur. Probabilistic methodologies ba
19、sed on reduced LMS availability may enhance the possibility of frequency sharing, however this issue requires further study. Typical technical parameters are generally used to establish appropriate sharing criteria. Those parameters may not reflect the existing LMS usage of the band. Specifically in
20、 the case that the LMS band is divided into sub-bands and used for particular types of LMSs, each with their own particular set of operating characteristics, different revised sharing criteria may apply to each of them. Where an administration wishes to establish a new system and appropriate sharing
21、 criteria have not been finalized, the measures outlined below should be considered to ensure that harmful interference is not caused to the existing service or the proposed new service. 2.1 this option may be limited. Initially, geographical separation will be a consideration, but as adjacent borde
22、r areas will be most affected, 2.2 Where practicable it may be possible to identify spectrum for the proposed BSS(s) which takes advantage of the operational characteristics of particular types of LMS used in the shared band. For example, it may be possible to use the discrimination of certain types
23、 of LMS receive antennas towards the satellite orbit to gain additional protection of the LMS. 2.3 may be implemented (Recommendation ITU-R SM.856). Where practicable methods such as interference cancellers, special screening, and adaptive antenna systems 2.4 In the longer term, moves to the use of
24、improved transmission techniques, such as spread spectrum (Recommendation ITU-R SM. los), coding techniques, automatic power control, and energy dispersal, may further facilitate inter-service sharing. COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services
