1、 Rec. ITU-R M.1234-1 1 RECOMMENDATION ITU-R M.1234-1 Permissible level of interference in a digital channel of a geostationary satellite network in the aeronautical mobile-satellite (R) service (AMS(R)S) in the bands 1 545 to 1 555 MHz and 1 646.5 to 1 656.5 MHz and its associated feeder links cause
2、d by other networks of this service and the fixed-satellite service (Question ITU-R 83/8) (1997-2006) Scope In this Recommendation, the allowable aggregate interference level of 20% of the total noise power in AMS(R)S channel, and the single-entry interference level of 6% of the total noise power in
3、 AMS(R)S channel, are specified. The ITU Radiocommunication Assembly, considering a) that the bands 1 545 to 1 555 MHz and 1 646.5 to 1 656.5 MHz are allocated to the mobile-satellite service (MSS), including AMS(R)S which is reserved for communications relating to safety and regularity of flights (
4、see provisions No. 1.36, 1.59, 5.357A and Article 44 of the Radio Regulations (RR); b) that the MSS including AMS(R)S usually utilizes the bands allocated to the fixed-satellite service (FSS) for its feeder links; c) that the provision No. 4.10 of the RR recognizes that safety services require speci
5、al measures to ensure freedom from harmful interference; d) that there is a need to prevent harmful interference to the AMS(R)S; e) that interference between networks of the MSS and between those of the MSS and the FSS contributes to the noise in the network and thus should be taken into account; f)
6、 that the International Civil Aviation Organization (ICAO) Standards and recommended practices (SARPs) provide technical data for AMS(R)S operations; g) that the mean interference noise power should be an appropriate fraction of the total noise power permitted in the hypothetical reference circuit;
7、h) that it is desirable that the increase in the bit error ratio (BER) due to interference from other satellite networks should be a fraction of the total BER specified in Recommendation ITU-R M.1037, bit error performance objectives for AMS(R)S radio link; j) that the desired signal, the interferin
8、g signal, and the noise-power levels vary with the operational and environmental conditions in a manner that can be portrayed as a statistical parameter; k) that FSS feeder links for AMS(R)S do not have any priority with respect to FSS feeder link stations operating with other FSS systems, 2 Rec. IT
9、U-R M.1234-1 recommends 1 that the MSS networks operating in the frequency bands 1 545 to 1 555 MHz and 1 646.5 to 1 656.5 MHz and using geostationary satellite, should be designed and operated in such a manner that the total interference power level in a digital channel in the AMS(R)S, caused by th
10、e earth station and space station transmitters of all other MSS and FSS networks should not exceed 20% of the total noise power at the input to the demodulator which would give rise to the bit-error ratio performance objectives as specified in Recommendation ITU-R M.1037; 2 that the maximum permissi
11、ble level of interference power in any such digital channel in the AMS(R)S caused by the transmitters of another mobile-satellite network or fixed-satellite network, should not exceed 6% of the total noise power at the input to the demodulator which would meet the bit error ratio performance objectives as specified in Recommendation ITU-R M.1037.
