1、 Recommendation ITU-R M.1473-1(01/2010)Methodology to evaluate the impact of interference from time division multiple access/frequency division multiple access (TDMA/FDMA) mobile-satellite service (MSS) space-to-Earth transmissions on video baseband performance in TV-FM analogue line-of-sight fixed
2、servicereceivers in the frequency range 1-3 GHzM SeriesMobile, radiodetermination, amateurand related satellite servicesii Rec. ITU-R M.1473-1 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all
3、radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences
4、 and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and lic
5、ensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Recommendations (Also available onli
6、ne at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services
7、P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequen
8、cy standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2010 ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoeve
9、r, without written permission of ITU. Rec. ITU-R M.1473-1 1 RECOMMENDATION ITU-R M.1473-1*Methodology to evaluate the impact of interference from time division multiple access/frequency division multiple access (TDMA/FDMA) mobile-satellite service (MSS) space-to-Earth transmissions on video baseband
10、 performance in TV-FM analogue line-of-sight fixed service receivers in the frequency range 1-3 GHz (Questions ITU-R 201/4 and ITU-R 118/5) (2000-2010) Scope This Recommendation provides a methodology to assess the impact of interference from TDMA/FDMA mobile-satellite service (MSS) space-to-Earth t
11、ransmissions on video baseband performance in TV-FM analogue line-of-sight fixed service (FS) receivers in the frequency range 1-3 GHz. This methodology may also be used in detailed MSS/FS coordination to further refine the results obtained implementing the methodology described in Recommendation IT
12、U-R M.1319. The ITU Radiocommunication Assembly, considering a) that the frequency band 1 518-1 525 MHz is allocated to the MSS (space-to-Earth) and the fixed service (FS) on a co-primary basis in all Regions; b) that the frequency band 1 525-1 559 MHz is also allocated to the MSS (space-to-Earth) o
13、n a primary basis in all Regions; c) that the frequency band 1 525-1 530 MHz is also allocated to the fixed service on a primary basis in Regions 1 and 3 and the frequency band 1 550-1 559 MHz is also allocated to the fixed service on a primary basis in some countries; d) that the frequency bands 2
14、170-2 200 MHz in all Regions and 2 160-2 170 MHz in Region 2 are allocated to the MSS (space-to-Earth) and the fixed service on a co-primary basis; e) that transmissions from mobile satellites could cause interference to line-of-sight (LoS) fixed service receivers operating in these bands; f) that s
15、uch interference involves time-varying phenomena such as interference geometry, propagation conditions, and MSS traffic; g) that computer simulation usually is the only way to accurately evaluate such interference; h) that the output of such simulations is typically in the form of C/I, C/N and C/(N
16、+ I) statistics into the given fixed service systems; *This is a joint Radiocommunication Study Groups 4 and 5 Recommendation and any revision shall be undertaken jointly. 2 Rec. ITU-R M.1473-1 j) that the impact and acceptability of such interference in most cases may be assessed in detailed bilate
17、ral coordination by studying via computer simulation the radio frequency C/N, C/I and C/(N + I) statistics as described in Recommendation ITU-R M.1319; k) that, in some critical cases, there may be a need during detailed bilateral coordination to evaluate via computer simulation the interference imp
18、act on analogue TV-FM fixed service video baseband performance objectives, recommends 1 that the methodology in Annex 1 may be used in detailed bilateral coordination between concerned parties for detailed assessment of the impact of interference from TDMA/FDMA MSS satellites in the 1-3 GHz MSS allo
19、cations on video baseband performance in analogue TV-FM LoS fixed service receivers, in cases where the results obtained by the methodology described in Recommendation ITU-R M.1319 needs further refinement (see Notes 1, 2 and 3). NOTE 1 The application of the methodology in this Recommendation will
20、require the development of algorithms or calculation procedures to address the implementation of the considerations described. The use or adaptation of these algorithms or procedures in any bilateral coordination would be subject to agreement by the concerned parties. NOTE 2 In countries where a lar
21、ge number of fixed service systems are in operation, it may be sufficient to apply the analysis to a representative set of existing fixed service systems, using actual fixed service parameters, especially taking into account those fixed service systems that are likely to be most sensitive to interfe
22、rence. The most sensitive fixed service systems are usually those oriented close to the worst-case azimuth direction; this direction can be established based on the orbital characteristics of the MSS system. However, this is a matter that will require agreement between the concerned parties. NOTE 3
23、In the case of GSO MSS systems the calculations are significantly simplified, since there is no need to simulate the orbital mechanics of the MSS constellation, however the potential of interference from multiple GSO MSS satellites may need to be considered when evaluating the impact of interference
24、. Annex 1 Methodology to evaluate the impact of interference from TDMA/FDMA MSS systems on video baseband performancein TV-FM analogue LoS fixed service receivers in the frequency range 1-3 GHz 1 Introduction Sharing between MSS and fixed service involves time varying phenomena such as interference
25、geometry, propagation conditions etc. Simulation is usually the only way to accurately evaluate interference between MSS and fixed service systems. The output of such simulations is typically in the form of radio-frequency C/I, C/N and C/(N + I) statistics presented usually as a cumulative distribut
26、ion function. Rec. ITU-R M.1473-1 3 Recommendation ITU-R M.1319 provides a methodology whereby inter alia baseband performance objectives for analogue FDM-FM and TV-FM fixed service systems provided in Recommendations ITU-R F.3931and ITU-R F.5552can be translated into equivalent radio-frequency C/(N
27、 + I) requirements for an associated percentage of time, with if necessary appropriate scaling to address actual fixed service routes of shorter length than the reference circuits. These equivalent radio-frequency performance objectives are plotted on the cumulative distribution plots of C/(N + I) i
28、n order to determine if the interference from MSS satellites is acceptable. The method described in Recommendation ITU-R M.1319 although it requires extensive computer simulation is relatively straightforward to implement in software, since all calculations and comparisons are undertaken in the radi
29、o-frequency domain. The methodology of proposed Recommendation ITU-R M.1319 should be used in the detailed coordination phase between administrations, when coordination is formally required and triggered in application of the Radio Regulations (RR) Article 9 and RR Appendix 5, in order to determine
30、if interference is acceptable or not considered in the context of actual fixed service system information and the relevant ITU-R performance and availability objectives. In some cases during the bilateral coordination phase, it may be necessary for the parties concerned to further examine the impact
31、 of MSS interference on the performance objectives of analogue fixed service systems. This could be the case where the results of the simulation method described in Recommendation ITU-R M.1319 are not sufficiently definitive to enable conclusion of frequency coordination. The objective of this annex
32、 is to present methodologies to evaluate from radio-frequency C/I and C/N statistics the video baseband performance impairments more accurately for TV-FM analogue fixed service carriers taking into account the effects of varying frequency separations that would exist for multiple TDMA/FDMA interferi
33、ng carriers, recognizing that the interference reduction factor or B factor and the protection ratio requirements of Recommendation ITU-R SF.766 indicate a strong dependence on frequency separation between the wanted and the interfering carriers. The methodology presented in this annex necessarily i
34、nvolves more sophisticated computer simulation tools than those described in Recommendation ITU-R M.1319 and is expected to require considerably more computer resources to execute. 2 Methodology for TV-FM fixed service systems 2.1 Reference TV-FM fixed service system for simulation In the detailed c
35、oordination phase, it is expected that actual analogue fixed service route parameters will be available in order to assess the impact of MSS interference. It is noted that, in the 1-3 GHz range, the intermediate fixed service stations in a fixed service modem section are usually equipped with IF rep
36、eaters. The demodulation to the baseband takes place only at the terminal station. Since the demodulation to baseband does not take place at the intermediate repeaters, it is only necessary to calculate the baseband interference at the last/terminal repeater in the actual fixed service route. 1Recom
37、mendation ITU-R F.393 was suppressed in 2007. However some fixed systems may continue to exist for which this Recommendation would be applicable. 2Recommendation ITU-R F.555 was suppressed in 2007. However some fixed systems may continue to exist for which this Recommendation would be applicable. 4
38、Rec. ITU-R M.1473-1 According to Recommendation ITU-R F.555, in the 2 500 km hypothetical reference circuit for the transmission of television signal, the ratio (dB), of the nominal amplitude of the luminance signal to the r.m.s. amplitude of the weighted noise measured under the conditions given in
39、 Parts B and C of ITU-T Recommendation J.61, should not fall below the following values: 57 dB for more than 20% of a month; 45 dB for more than 0.1% of a month. The Recommendation also indicates that a S/N value of 53 dB is desirable for more than 1% of any month. 2.2 Estimation of statistics of ba
40、seband video S/(N + I) 2.2.1 General description The impact of interference from MSS systems employing narrow-band modulation/access schemes into a TV-FM baseband video signal can be assessed as follows. Using the simulation methods described in Recommendation ITU-R M.1319, at each time step in the
41、simulation period for each fixed service receiver in an fixed service route one can estimate the C/I and C/N values, where now the C/I levels are computed due to each individual TDMA/FDMA MSS carrier within the bandwidth of the TV-FM fixed service receiver. In principle, one should determine the bas
42、eband noise and interference at each hop and accumulate them along the route. However, noting that the baseband noise and interference at each hop are linearly related to the respective C/N and C/I for that hop, it is equivalent to accumulate the radio frequency noise and interference along the rout
43、e and to determine the baseband noise and interference at the terminal station from these overall C/N and C/I values. Thus, the overall C/N and C/I levels due to each carrier at each time step at the terminal station in the actual fixed service route comprising of (n + 1) stations, where n is the nu
44、mber of hops, can be assessed as below. The overall C/N (dB) at the terminal fixed service station is given by the following expression: =11.010log10iNCtotaliNC(1a) The overall C/I (dB) due to each individual interfering carrier at the terminal fixed service station is given by the following express
45、ion: =11010log10iIC.totaliIC(1b) +=+110101010log10 totaltotalNC.IC.totalINC(2) The overall S/N (dB) at the terminal fixed service station due to each individual interfering carrier can be expressed as follows: S/N = S/(Nth+ I) = 10 log ( )/(1.0)/(1.01010ISNSth+ (3) Rec. ITU-R M.1473-1 5 where S is t
46、he wanted signal, Nththe thermal noise an I the interference. The S/I (dB) at the terminal fixed service station due to each individual interfering carrier in turn can be expressed as follows: S/I = C/I + B (4) where B is the video interference reduction factor. In Report ITU-R SF.449 (1990), an exp
47、ression for B is obtained through measurements which can be expressed as follows: B = 6 + 20 log (F) (5) and F being the peak to peak deviation (MHz). Assuming a peak-to-peak deviation of 10 MHz the value of B can be calculated as 26 dB. The expressions for computing B factor for interference into T
48、V-FM carriers are taken from the published literature Wu and Chang, 1985. The interference reduction factor can be expressed as follows: B = S/N C/I = 20 log 2/112)75/()/(7.0nPAA (6) in which S/N is the ratio of nominal peak voltage of the baseband signal to the r.m.s. interference noise voltage exp
49、ressed (dB), C/I = 20 log A1/A2, A1/A2is the ratio of the unmodulated carrier amplitude of the interfered signal to that of the interfering signal and Pnis the baseband weighted interference noise power. Equation (6) was used in the following analysis. The noise Pnis obtained from the following equation: ()()=nnnCnf hnf nfFAAP200022122g752(7) where: g(nf0) : weighting function h(nf0) : pre-emphasis characteristic of the TV signal F : peak-to-peak
