1、STD-ITU-R RECMN S.11255-ENGL 1997 48552112 0530354 8bb m 1 Rec. ITU-R S.1255 RECOMMENDATION ITU-R S. 1255 USE OF ADAPTIVE UPLINK POWER CONTROL TO MITIGATE CODIRECTIONAL INTERFERENCE BETWEEN GEOSTATIONARY SATELLITE ORBIT/FMED-SATELLITE SERVICE (GSO/FSS) NETWORKS AND FEEDER LINKS OF NON-GEOSTATIONARY
2、AND BETWEEN GSO/FSS NETWORKS AND NON-GSO/FSS NETWORKS SATELLITE ORBITAUOBILE SATELLITE SERVICE (NON-GSO/MSS) NETWORKS (Questions IT-R 20614 and IT-R 23 1/4) (1 997) The ITU Radiocommunication Assembly, considering a) that the World Radiocommunication Conference (Geneva, 1995) (WRC-95) made provision
3、s for feeder links of non-GSOMSS networks and GSO/FSS networks to operate on a shared basis in portions of the 20/30 GHz FSS bands, and also for non-GSO/FSS networks to operate on a shared basis with GSO/FSS networks in other portions of these bands; b) operating in these shared bands; that the use
4、of interference mitigation techniques, as shown by studies, will facilitate sharing between networks c) that feeder links of non-GSONSS networks, non-GSORSS networks, and GSOFSS networks intending to operate in the 20/30 GHz bands may include adaptive uplink power control in the system design in ord
5、er to overcome the effects of impaired propagation; d) strategies, including adaptive uplink power control; that Recommendation ITU-R S. 1061 contains useful design information for several fade countermeasure e) that when adaptive uplink power control is included in the design of these networks, it
6、may be feasible to use this adaptive power control not only for combating the effects of impaired propagation, but also to maintain system performance during times of increased levels of interference between these networks; 0 that the statistical nature of interference between feeder links of non-GS
7、OMSS networks and GSO/FSS networks, and between non-GSOFSS networks and GSOFSS networks, is significantly different from the statistical nature of impaired propagation at 20/30 GHz, recommend 1 that networks employing adaptive uplink power control in the portions of the 20/30 GHz FSS bands in which
8、feeder links of non-GSONSS networks and GSO/FSS networks share frequencies, and in the portions in which non-GSO/FSS networks and GSORSS networks share frequencies, should transmit the signals from their earth stations at the lowest possible power level which will achieve and maintain the desired li
9、nk quality with appropriate link margin; 2 that in networks intending to utilize adaptive uplink power control to combat the effects of increased levels of interference between feeder links of non-GSOMSS networks and GSO/FSS networks, and between non-GSORSS networks and GSOESS networks, consideratio
10、n should be given in the design of the adaptive power control algorithm to the temporal characteristics of the statistics of this interference as compared to the statistics of impaired propagation; 3 that the extent to which power control is used to combat interference between feeder links of non-GS
11、O/MSS networks and GSOESS networks, and between non-GSO/FSS networks and GSORSS networks should be defmed by network operators during the frequency coordination process, if it is to be used. 2 Rec. ITU-R S.1255 NOTE 1 -In networks where adaptive power control designed primarily to combat propagation
12、 fades has a limited ability to respond to short-term interference events, use of adaptive power control will result in these networks being more sensitive to short-term interference events, especially from sources operating without adaptive power control. NOTE 2 - When adaptive uplink power control
13、 is used to mitigate in-line interference between the feeder links of non-GSOMSS networks and GSOFSS networks, the possibility exists that this technique will be counter-productive when the earth stations are closely located. Depending on the interference geometry, and the relative interference leve
14、ls between the two networks, the increase in link power by one network to overcome interference may result in progressive increases in link power on both networks, leading to more interference between the two networks. Further studies are required to determine the minimum spacing of earth stations,
15、and how the adaptive power control algorithms may be designed to reduce this spacing. NOTE 3 - In cases where the maximum level of “in-line” interference from the uplink of Network A to the uplink of Network B is substantially below the acceptable level, but simultaneously the “in-line” interference
16、 from Network B to NetworkA is substantially above the acceptable level, it may be advantageous for the adaptive power control of Network A to be designed to combat “in-line” interference (in addition to combating propagation fades) but for the adaptive power control of Network B to be designed to combat propagation fades only.
