1、220 CCIR RECWNu739 92 4855212 0518840 208 Rec. 739 RECOMMENDATION 739 ADDITIONAL METHODS FOR DETERMINING IF DETAILED COORDINATION Is NECESSARY BETWEEN GEOSTATIONARYSATELLITE NETWORKS SAME FREQUENCY BANDS IN THE FIXED-SATELLITE SERVICE SHARING THE (Question 49/4) (1992) The CCIR, considering that FSS
2、 networks may share the same frequency bands; that these networks may cause and experience mutual interference; that this mutual interference can be minimized through coordination; that the method described in Recommendation 738 is very conservative; that additional methods may be useful to determin
3、e if detailed coordination is necessary, 4 b) C d) e) recommends 1. administrations concerned, to determine if detailed coordination is necessary: that, to the extent data is available, the following methods be used, by mutual agreement between the - - that the following Notes should form part ofthi
4、s Recommendation. the normalized ATITmethod described in Annex 1; the power density-averaging bandwidth method described in Annex 2; 2. Note 1 -The normalized AT/T method for determining the interference level using the normalized values of the apparent increase in equivalent noise temperature, is b
5、ased on the technique shown in Appendix 29 to the Radio Regulations, appropriately modified to give more accurate results. This approach consists in using a set of predetermined values for ATIT which depends upon the types of wanted and interfering carriers involved, instead of the single 6% value g
6、iven in Appendix 29. Note 2 - The power density-averaging bandwidth method is an extension of the Appendix 29 AT/T method that allows the calculation of the interference power for any interfered-with carrier bandwidth. This method may be applied for determining the need for detailed coordination and
7、 may also be used in more detailed coordination. ANNEX 1 Method of the normalized equivalent noise temperature of the satellite link 1. Introduction This method is based on the technique shown in Appendix 29 to the Radio Regulations and described in Recommendation 738 appropriately modified to give
8、accurate results. To do so, the threshold of 6% used in Appendix 29 is replaced by thresholds which depend on the carriers involved and which meet the CCIR criteria. COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesCCIR RECMN*739 92 m 4
9、855232 0538843 344 Rec. 739 221 2. Normalized values for the relative increase in the admissible equivalent Link noise temperature 2.1 Definition The method involves determining the overall increase in equivalent link noise temperature due to the various types of transmission in the two networks. Th
10、e normalized values for the relative increase in equivalent link noise temperature are given by: where: No : thermal noise density corresponding to the equivalent noise temperature of the satellite link UNO : ratio of interfering power to the thermal noise density of the wanted carrier B2 : bandwidt
11、h defined by the ratio of the interfering carrier power P to its maximum spectral power density pJm: . 2.2 Values for various carrier types The method for computing Z/No and (AT/T)N is given in Q 3 to 9. The calculation method for (AT/T)N depends on the type of wanted and interfering carriers. Five
12、types are considered: - FDM-FM, - SCPC-FM, - digital SCPC (SCPC-DIG), - wideband digital (DIG-BB), - FM-television (FM-TV). For a given type of wanted carrier and a given type of interfering carrier, the (AT/T)N value obtned (using the method which corresponds to this pair of carrier types) depends
13、on carrier parameters such as bandwidth and coding. In order to limit the necessary computations, each general carrier type is broken down into various sub- headings so that, for each pair of carrier types, the carrier parameters no longer affect (ATION (as long as these parameters lie in the range
14、specified for each type) (see Table 1). Thus (AT/T)N can be determined simply from the knowledge of the type of the two carriers. Carriers are classified according to their type. An initial analysis of the carriers leads to the identification of about 50 different types: - about 20 FDM-FM, character
15、ized by the number of channels and allocated band, - several SCPC-FM, characterized by the allocated band, - about 15 DIG-BB, characterized by the bit rate, type of coding, and number of states, - several SCPC-DIG, characterized by the bit rate, type of coding, and number of states, - several FM-TV,
16、 characterized by the allocated band and energy dispersai characteristics. In order to simplify the presentation of the table of thresholds, the 50 types of carriers have been gathered in The corresponding values of ATIT for each pair of wanted and interfering categories of types of carriers is 12 c
17、ategories as given in Table 2. given in Table 3. COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesCCIR RECMN*39 92 4855232 0538842 O80 W 222 DM-FM NC 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 SCPCA No. 23 24 25 26 27 SCPC
18、N No. 28 29 30 31 32 NUM-LB No. 33 34 35 36 37 38 39 40 41 42 43 44 45 FM-Tv No. 46 47 48 49 50 12 1.3 12 2.5 24 2.5 60 2.5 72 60 2.5 5.0 132 5.0 192 5.0 96 7.5 192 7.5 252 7.5 132 10.0 252 10.0 312 10.0 252 15.0 432 15.0 432 20.0 612 20.0 432 25.0 792 25.0 972 25.0 972 36.0 Type o. 020 0.025 0.030
19、0.090 0.180 Type 0.064 0.085 0.128 0.256 0.512 Type 2Q 34 44 8Q 104 174 254 34Q 404 504 120Q 139Q 1474 I Rec. 739 TABLE 1 Standard carrier types NN 12 12 24 60 72 60 I32 192 96 192 252 132 252 312 252 432 432 612 432 792 972 972 NIE 4 4 4 4 4 NE 4 4 4 4 4 4 4 4 4 4 4 4 4 Af Tv.20 TV.30 6.2 Tv.35 5.0
20、 Tv.36 11.0 SCPCA : SCPC (analogue) SCPCN : SCPC (digital) NUM-LB : wideband (digital) NIV : number of channels NIE : number of states Boc. : occupied bandwidth Bo, (MHZ) 1.13 2.2 1.96 2.25 2.25 3.96 4.45 4.51 5.87 6.40 6.74 7.50 8.49 8.96 12.39 12.95 17.99 17.70 20.59 22.34 25.00 35.99 Bo, WZ) 20.0
21、 25.0 30.0 90.0 180.0 Bo, (NZ) 38.0 50.0 150.0 300.0 600.0 Bo, (MHZ) 1.44 1.84 2.25 5.0 5.0 10.2 18.0 20.6 20.0 25.6 75.0 82.0 110.0 Bo, (MHz) 17.5 20.0 30.0 30.0 32.0 - Af : fmin orHz1 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 12.0 fmin
22、 (HZ) 0.3 0.3 0.3 0.3 fm (HZ) 60.0 60.0 108.0 252.0 300.0 252.0 552.0 804.0 408.0 804.0 1052.0 552.0 1052.0 1300.0 1052.0 1796.0 1796.0 2 540.0 1796.0 3 284.0 4 028.0 4 028.0 fmax (Wz) 3.4 3.4 3.4 3.4 3.4 0.3 Bite rate (kbils) 64.0 85.0 128.0 256.0 512.0 Bite rate (Mbils) 2.048 3.072 4.096 8.448 10.
23、0 17.0 24.6 34.368 40.0 50.0 120.0 139.264 147.0 Afst (Hz) 108.5 238.9 163.4 136.5 124.5 270.1 223.5 180.0 359.8 297.2 259.7 430.0 357.4 320.0 576.4 400.2 615.8 453.7 727.3 498.4 410.0 796.7 L (k 12.0 8.5 3.4 Afm (Hz) 159.0 350.0 275.0 276.0 261.0 546.0 529.0 459.0 799.0 758.0 733.0 1020.0 1009.0 10
24、05.0 1627.0 1479.0 2 276.0 1 996.0 2 688.0 2 494.0 2 274.0 4 417.0 5) 3 Afpm Afpnm fbal (MHz) (MHZ) (Hz) 1 .o 2.0 60130 I .o 2.0 50 2.0 4.0 50 2.0 4.0 50125 1 .o 2.0 50 frequency deviation freauencv deviation modrilated carrier Afpm : . 15 MHz Bot( 3 MHz 3 MHz 7 MHz 50 I Boc 15MHz I 39-45 I AfS7 11
25、11 12 23 9 11 22 39 21 16 5 Af 11 13 19 45 9 21 44 77 22 36 32 10 TABLE 3 Single carrier to single carrier ATIT threshold values I Interfering carrier I FDM-FM Wideband digital Il I FM-Tv I scpc I I I CFM (2) 1 223 4 350 8 458 22 257 3 085 10 712 21 853 38 565 9 11 16 046 5 098 Note 1 - When several
26、 equal power interfering carriers of one of the types given in Table 1 are included in the wanted bandwidth, these values should be decreased in accordance with the number of these interfering carrier. (1) (2) (3) (4) The table reflects the value for the most sensitive carrier in any range. This Tab
27、le should not be used for carrier types not included in Table 1. Criterion used 800 pWOp single entry and 7000 pWOp total. For PM-TV interference a 20% allocation to external satellite interference is assumed. Criterion used: 6% sin le en and 70% total. For FM-TV interference a 20% allocation to ext
28、ernal satellite interferences is assumed and a value of12.3 3 is assumed for energy per bit to noise power density ratio (BER = 106). COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesCCIR RECMN*739 92 W 4855212 0518844 953 224 Rec. 739
29、3. Parameters used in the computation of Z/No and (ATIT)N The parameters used are as follows: Bo : Bi : IINO : bandwidth of the wanted signal (Hz) bandwidth of the interfering signal (Hz) ratio of interfering carrier power-to-noise power density CINO : CII : ratio of wanted carrier power-to-noise po
30、wer density ratio of wanted-to-interfering carrier power B2 : bandwidth defined by the ratio of interfering power F to its maximum spectral power density I; pl, = PIB, a: fraction of interfering signal power received after filtering by the wanted signal receiver filter No : thermal noise power densi
31、ty corresponding to the equivalent noise temperature of the satellite link N: noise power N = No . Bo. Admissible normalized values for the relative increase in equivalent link noise temperature are given by: 4. Interference criteria In the computation of (ATIVN for analogue FDM-Fh4 signals, the equ
32、ivalent link noise temperature should correspond to a noise power in a telephone channel of 7 O00 pWOp for systems with frequency re-use and 6 500 pWOp for systems without frequency re-use (Recommendtions 466 and 356). For digital signals, the equivalent link noise temperature should correspond to 7
33、0% (for systems with frequency re-use) and 65% (for systems without frequency re-use) of the total noise power level which would give rise to a bit error ratio of 1W (Recommendations 523 and 558). For TV/FM type signals, the criterion given in Recommendation 483 should be applied. Accordingly, takin
34、g into account interference from terrestrial radio links, the single-entry interference criterion referred to permissible video noise is 5%. For an SCPC-FM signai, the criterion for interference from other than TV-FM signals is assumed to be 600 pWOp in a channel for an equivalent link noise tempera
35、ture of 7000 pWOp for systems with frequency re-use and 6 500 pWOp for systems without frequency re-use. For SCPC-PSK and SCPC-CFM carriers, the criterion for interference from TV-FM signais should correspond to Recommendation 67 1. COPYRIGHT International Telecommunications Union/ITU Radiocommunica
36、tionsLicensed by Information Handling ServicesCCIR RECMN*739 92 = Y855212 0518845 8T Rec. 739 225 It should be noted that if the spectrum of the wanted signal is broader than the spectrum of the interfering signal, total interference due to all interfering signals from the same network within the ba
37、ndwidth of the wanted signal should be considered. 5. FDM-FM wanted carriers At a 1 mW reference point, the psophometrically-weighted level Np of noise-like baseband interference is given in pWOp by: c 10 log Np = 87.5 - B - 10 log 7 dB Sf f = 87.5 - P i- 10 log b + 10 log Du, fo) - 20 log - C = -3-
38、1010g7 where: B: interference reduction factor b: telephone channel bandwidth (Hz) Sf: $n : Dcf, fo) : convolution product of wanted and interfering spectra r.m.s. test-tone deviation of the wanted signal (Hz) top baseband frequency of the wanted multiplex signal (I fo : f: P = 10 log p(t7fm): pre-e
39、mphasis (dB). Thermal noise after demodulation is given by: separation between carrier frequencies of wanted and interfering signals (Hz) central frequency of the selected channel, located in the baseband of the wanted signal (Hz) dB c Sf No f 10 log Nth = 87.5 -P - 10 log-+ 10 log b-20 log- where:
40、No = kT : noise density power on the wanted link with k: Boltzmanns constant and T: thus: equivalent satellite link noise temperature as defined in No. 168 of the Radio Regulations lolog =lOlog-3+10logDcf,f0) I dB No The single entry criterion established by Recommendation 466 corresponds to Np = 80
41、0 pWOp, for an Nth value equal to 7 O00 or 6 500 pWOp. As an example, for 7 O00 pWOp which is applicable to systems with frequency re-use: I 2 0.2286 - = 0.1143 - - No Dcf, fol - Dcf, fol hence: COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling
42、Services226 6. 6. I thus: thus: with: where: 6.2 where 7. 7.1 CCIR RECMN*39 92 4855212 0518846 726 Rec. 739 SCPC-FM wanted carrier Interference from un FM-TV currier In this case the 10 log C/I = 13.5 + 2 log 6 - 3 log (i/lO) criteria must be respected (Recommendation 671), I CIC i0.3 -.-_-. N - N c
43、 - N 101.65 .60.2 Af : peak-to-peak frequency deviation of TV signal due to energy dispersal (Hz) i : For the example given in Table 1, thermal noise is given by: percentage of total predemodulation noise allocated to internetwork interference. 10 log Nth= 188.7 - 10 log C/NO - 20 log 6f dB 6f: r.m.
44、s. deviation of the SCPC-FM wanted signal (Hz). After companding, the following is generally obtained: CINO = 1014.9/6f Interference from u currier other than FM-TV All other interfering signals have spectra significantly broader than the wanted signal spectrum (SCPC), thus: Np = Ntl, = 800 pWOp: pe
45、rmissible single-entry interference criterion 6 500 pWOp or 7 O00 pWOp corresponding to systems without or with frequency re-use. Thus for 7 O00 pWOp: goo 11.4% Digital SCPC wanted carrier Interference from un FM-TV currier In this case the criterion 10 log C/Z = 10 log C/N + 6.4 + 3 log 6 - 8 log (
46、i/lO) must be respected (Recommendation 671). COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesRec. 739 227 thus: thus: j0.8 - BO $ N= 101.44 . 00.3 * BZ with: Af : peak-to-peak frequency deviation of TV signal due to energy dispersal (
47、Hz) i : For the example given in Table 1, CINO is given by: percentage of total pre-demodulation noise allocated to internetwork interference. where: E : energy per bit Du : useful bit rate No : noise power density. 7.2 Znterferencefiom a carrier other than FM-TV Ail other signals have spectra signi
48、ficantly broader than the wanted signal spectrum (SCPC). Thus for systems with frequency re-use: $1 = g = 8.57% 8. Broadband digital wanted carrier 6 70- Recommendation 523 gives the CCIR criterion: aIlNth = - - 8.57 % (for systems with frequency re-use). 8.1 - ifBoBi: a= 1 Interference from a digit
49、al carrier then: I I Ntii I NO- Ntti NO Nth -e Bo = 0.0857 Bo and Bz = BI -.-= thus: E = 0.0857 . - BO - 0.0857 - BO B2 - Bi COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services228 hence: Bi B2 % = 0.0857 - = 0.0857 8.2 Interference porn an analogue carrier - ifBoBl: a= 1 then: I I Nth AT BO No-Nth No N B2 - - - . - = 0.0857 Bo and y = 0.0857 . - 9. FM-TV wanted carrier In this case, the criterion is: 10 log Clal 2 X dB, where X could be a variable. However, for the example given in Table 1, the va
