1、 Rec. ITU-R S.1524 1 RECOMMENDATION ITU-R S.1524 Coordination identification between geostationary-satellite orbit fixed-satellite service networks (2001) The ITU Radiocommunication Assembly, considering a) that the Plenipotentiary Conference (Minneapolis, 1998) agreed, through Resolution 86, on the
2、 need for improved coordination and notification of satellite networks; b) that there is a need to accelerate the identification of geostationary-satellite orbit fixed-satellite service (GSO FSS) networks with which coordination is required; c) that simple methods are needed for identifying the nece
3、ssary co-frequency GSO FSS networks with which coordination must take place and which can be used in fulfilment of the objectives of Resolution 86; d) that typical network characteristics of 6/4 GHz, 13-14/11-12 GHz and 30/20 GHz GSO FSS networks are well known; e) that in many parts of the GSO co-f
4、requency FSS networks in bands identified in considering d) above are closely spaced with overlapping beams; f) that the operators of such networks have extensive experience in coordinating satellite systems with other co-frequency satellite systems; g) that where applicable, the off-axis equivalent
5、 isotropically radiated power (e.i.r.p.) density recommended maximum levels on GSO FSS earth stations toward an adjacent GSO FSS network and power flux-density limits on GSO FSS space stations at the surface of the Earth are among the most important technical parameters used in defining orbital sepa
6、ration; h) that a coordination arc can be defined around a given network such that interference between that network and networks outside that arc may typically be considered negligible compared to the interference from networks within that arc; j) that network parameters developed to accommodate ne
7、tworks within the coordination arc would likely help to accommodate networks at greater orbital spacing; k) that the coordination arc, by itself, may not be sufficient in some cases to identify all networks which might cause interference to or receive interference from a new network; l) that the Wor
8、ld Radiocommunication Conference (Istanbul, 2000) adopted Resolution 55 (WRC-2000) to bring into effect temporary procedures for improving satellite network coordination, including modifications to Articles 9, 11 and Table 5-1 of Appendix 5 of the Radio Regulations (RR), 2 Rec. ITU-R S.1524 recommen
9、ds 1 that determination of the need for coordination between GSO FSS networks should be based on coordination arcs of 10, in the bands 3 400-4 200 MHz, 5 725-5 850 MHz (Region 1) and 5 850-6 725 MHz, 9 in the bands 10.95-11.2 GHz, 11.45-11.7 GHz, 11.7-12.2 GHz (Region 2), 12.2-12.5 GHz (Region 3), 1
10、2.5-12.75 GHz (Regions 1 and 3), 12.7-12.75 GHz (Region 2), and 13.75-14.5 GHz, and 8 in the bands 17.7-20.2 GHz and 27.5-30 GHz about the nominal orbital positions of those networks; 2 that, although the full RR Appendix 4 data must still be provided, the information in Annex 1 is sufficient, and s
11、hould be used, for determining whether the threshold coordination arc conditions defined in recommends 1 are exceeded for a co-frequency GSO FSS network; 3 that an administration, on its own initiative or with the assistance of the Radiocommunication Bureau (BR) in application of No. 9.41 and other
12、relevant provisions of the RR (e.q. No. 13.1), may request that a co-frequency GSO FSS satellite network outside the coordination arc be included in coordination when the administration can demonstrate by analysis that the increase in the system noise due to the proposed network exceeds 6%; 4 that t
13、he administration filing the request for coordination, on its own initiative or with the assistance of the BR in application of No. 9.41 and other relevant provisions of the RR (e.q. No. 13.1), may request that a co-frequency GSO FSS satellite network within the coordination arc be excluded from the
14、 coordination when the filing administration can demonstrate by analysis that the increase in system noise to the network, within the coordination arc due to the proposed network, is less than 6%. This is to be confirmed by the BR which will inform the concerned administrations. NOTE 1 In order to i
15、mplement recommends 3 and 4, the relevant RR Appendix 4 data should be used. NOTE 2 The coordination arc should apply to coordination only between satellite networks in the FSS using the GSO and operating in the same direction of transmission. NOTE 3 The bases for the values in recommends 1 are give
16、n in Annex 2. NOTE 4 In other FSS bands than those listed in recommends 1 and those covered by RR Appendix 30B, T / T of 6% would continue to apply. ANNEX 1 Information required for identification of administrations and satellite networks based on GSO coordination arcs A.1.a: Identity of satellite n
17、etwork A.1.f: Country symbol of the notifying administration A.3: Operating administration or agency A.4.a.1: Nominal geographic longitude of the space station on the GSO C.2.a: Assigned frequency C.3.a: Assigned frequency band. NOTE 1 All information required for identification of administrations a
18、nd satellite networks based on GSO coordination arcs is also required in RR Appendix 4 for notification or coordination of a GSO network. Accordingly the RR Appendix 4 item numbers are provided. Rec. ITU-R S.1524 3 ANNEX 2 Coordination identification between GSO FSS networks 1 Introduction This Anne
19、x deals with the appropriate coordination arc which may be adopted for identifying the need for coordination between GSO FSS networks in the bands 6/4 GHz, 13-14/11-12 GHz, and 30/20 GHz. The objective of the calculation is to define an orbital separation angle, , beyond which the increase in noise
20、temperature of the network subject to interference will not exceed 6%. Coordination would be required when a GSO network is within from the proposed network. The approach used is to examine the excess interference in typical FSS systems caused by other typical FSS systems at varying angular separati
21、ons, and assessing the resultant risk created by not coordinating the two networks at the separation value. 2 Results of studies 2.1 Methodology and assumptions The methodology used to calculate the separation angle between two GSO FSS networks is described below: First, the total carrier to noise +
22、 interference ratio (C/(N + I ) is calculated for the interfered with system. The aggregate interference from other GSO networks into the wanted system is set at 20% of the total system noise. The single-entry interference from one GSO network is 6% of the total system noise and allocated equally be
23、tween the uplink and the downlink direction. Generally, the interference in a link is dominated by the contribution of interference from one direction rather than the other. Thus, this assumption will give a larger separation angle than that in a case of treating each link direction separately with
24、the full 6% allowable interference allocated for each direction. The antenna pattern of the receiving earth station is assumed to comply with 29-25 log . For the uplink direction, the interfering transmitting earth station is assumed to be located at the wanted satellite maximum gain direction and t
25、he path losses are assumed to be the same for both the wanted and the interfering direction. The required separation angle will then be determined from the off-axis e.i.r.p. density radiation pattern of the interfering transmitting earth station. For the downlink direction, the interfering receiving
26、 earth station is assumed to be collocated with the wanted earth station. The required separation angle will then be determined from the interfering satellite e.i.r.p. density and the receiving antenna pattern of the interfered earth station. 4 Rec. ITU-R S.1524 2.2 System parameters The parameters
27、of the GSO networks used in this study are taken from the transparent (bentpipe) GSO link budget databases for the 13-14/11-12 GHz and 30/20 GHz bands. The fact that these carriers were given for the most sensitive GSO FSS links has been noted, however this database represents a suitable reference o
28、f GSO carriers for this purpose. It is also noted that for a typical GSO link budget, the separation angles would be smaller due to the high power of the GSO carriers. Table 1 shows the assumed off-axis e.i.r.p. density used in this study. The transmitting earth station off-axis e.i.r.p. density val
29、ues are taken from Recommendation ITU-R S.524 for both the 13-14/11-12 GHz and 30/20 GHz bands (in the case of 30/20 GHz band, Recommendation ITU-R S.524 contains off-axis e.i.r.p. density values only for the frequency range 29.5-30 GHz). TABLE 1 e.i.r.p. and antenna pattern of GSO FSS networks 2.3
30、Determination of single-entry carrier to interference (C /I ) due to interference from another GSO network This section describes the calculation required to determine the allowable interference from other GSO networks into an interfered-with GSO network from the parameters provided in these databas
31、es. Throughout this Annex, ratios expressed in lower case letters are used to denote power ratios and upper case letters are used when the power ratios are expressed in dB. The uplink is designated by the subscript and the downlink by the subscript . The total power from both uplink and downlink is
32、designated by the subscript t. The total carrier-to-system noise ratio of the wanted network which is comprised of thermal noise, internal noise and interference due to other GSO networks and terrestrial systems is determined as follows: 11111 Gf7Gf7Gf8Gf6Ge7Ge7Ge8Ge6+Gf7Gf7Gf8Gf6Ge7Ge7Ge8Ge6+Gf7Gf7
33、Gf8Gf6Ge7Ge7Ge8Ge6+Gf7Gf8Gf6Ge7Ge8Ge6=GfeGfdGfcGeeGedGec+tGSOtlterrestriatinternaltticicicncnic(1) where: c/(i + n)t: total carrier-to-system noise ratio (uplink and downlink direction) (c/n)t: carrier-to-thermal noise ratio from both uplink and downlink direction Frequency band (GHz) Interfering Tx
34、 earth station off-axis e.i.r.p. density (dB(W/40 kHz) Interfering Tx satellite e.i.r.p. density (dB(W/Hz) Wanted earth station antenna pattern 13-14/ 11-12 39-25 log for 2.5 7 22 29-25 log 30/20 19-25 log for 2.0 7 18 29-25 log Rec. ITU-R S.1524 5 (c/iinternal)t: carrier-to-internal interference ra
35、tio from both uplink and downlink direction (c/iterrestrial)t: carrier-to-terrestrial interference ratio from both uplink and downlink direction (c/iGSO)t: carrier-to interference ratio due to all other GSO networks from both uplink and downlink direction. Assuming that the aggregate interference du
36、e to all other GSO networks and the single-entry interference from one GSO network (both uplink and downlink) are 20% and 6% of the total system noise, respectively, we have: GefGeeGefGedGecGefGeeGefGedGecGefGfeGefGfdGfcGf7Gf7Gf8Gf6Ge7Ge7Ge8Ge6+Gf7Gf7Gf8Gf6Ge7Ge7Ge8Ge6+Gf7Gf8Gf6Ge7Ge8Ge6=GefGfeGefGf
37、dGfc0.80.061111SEI_GSOtlterrestriatinternaltticicncic(2) where: (c/iSEI_GSO)t: carrier-to-interference ratio due to one interfering GSO network. The total interference due to another GSO network is assumed to be allocated equally to both uplink and downlink direction. Thus, the C /ISEI_GSOin the upl
38、ink and downlink will be 3 dB higher than the total C /ISEI_GSOwhich is determined from equation (2). 3SEI_GSOSEI_GSOSEI_GSO+Gf7Gf7Gf8Gf6Ge7Ge7Ge8Ge6=Gf7Gf7Gf8Gf6Ge7Ge7Ge8Ge6=Gf7Gf7Gf8Gf6Ge7Ge7Ge8Ge6 tICICICdB (3) 2.4 Determination of the required uplink separation angle The separation angles for bo
39、th uplink and downlink are then calculated from the C /ISEI-GSOtaking into account the bandwidth difference between the wanted and interfering network. 3 Results of studies using maximum and minimum e.i.r.p. data The excess interference margins were calculated using INTELSAT IICM parameters. The val
40、ues used for the maximum interfering parameters are given in Table 2 and for the minimum receive parameters are given in Table 3, respectively. These parameters are considered typical of many systems in the FSS. In order to simplify the different combinations and types of carriers used in the INTELS
41、AT system, all carriers were categorized into one of four distinct types, namely: narrow-band digital carriers, wideband digital carriers, analogue frequency division multiplex/frequency modulation (FDM/FM) or companded frequency division multiplex (CFDM)/FM carriers, FM/TV (slowly swept) carriers.
42、The summary of the carrier parameters used in this study is given in Table 3. 6 Rec. ITU-R S.1524 TABLE 2 Uplink and downlink limits for use in calculating interference margins in Tables 4 and 5 Using the limits defined in 2, Table 4 gives the excess interference margin for the different types of ca
43、rriers at various orbital separations for the 6/4 GHz band, and Table 5 gives the excess interference margin for the different types of carriers at various orbital separations for the 13-14/11-12 GHz band. It should be noted that the interference margin computed from FM/TV into narrow-band carriers
44、assumes that the FM/TV carriers are modulated at all times with live video or test patterns in addition to the energy dispersal signal so that they can be treated as noise-like inter-ference with a maximum spectral density of 63 dBc/Hz. It is assumed that the interfering beam is copolarized and oper
45、ates co-frequency with the wanted network beam. A 1 dB of topocentric advantage is used. In the derivation of the worst-case interference margin given in Tables 4 and 5, the following assumptions were made. Based on these assumptions, improvement factors are also identified: For determining the upli
46、nk interference margin, it is assumed that the interfering earth station is located at the beam peak of the wanted network receive beam. For determining the downlink interference margin, it is assumed that the wanted receive earth station is located at the beam peak of the interfering transmit beam.
47、 This represents a worst-case condition and, on average, the interference margin could be improved by 2 dB. The carriers transmitted or received at the earth stations as assumed in this study are worst-case carriers. In general, such worst-case situations do not arise due to the compatibility requir
48、ements with the closer adjacent satellite networks, and the fact that the worst-case carriers of the interfering network are not co-frequency with the most sensitive carriers of the wanted networks. Based on these assumptions, the interference margin could be improved by up to 3 dB. The earth statio
49、ns side-lobe performance assumed in this study follow exactly the 29-25 log pattern of some ITU-R Recommendations. On average, the interference margin could be improved by 1 dB due to improved performance in actual side lobe. Taking into consideration the factors described above, the negative interference margins of up to 6 dB with respect to the T / T criteria could be considered acceptable. Furthermore, due to the fact that the measures to be adopted by the proposed satellite system in orde
