1、 Recommendation ITU-R M.1319-3(01/2010)The basis of a methodology to assess the impact of interference from a time division multiple access/frequency division multiple access (TDMA/FDMA) mobile-satellite service (MSS) space-to-Earth transmissions on the performance of line-of-sightfixed service rece
2、ivers in the frequency range 1-3 GHzM SeriesMobile, radiodetermination, amateurand related satellite servicesii Rec. ITU-R M.1319-3 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommun
3、ication 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 and Radioc
4、ommunication 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 licensing decl
5、arations 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 online at http:
6、/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 P Radiowave
7、 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 frequency standard
8、s 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 whatsoever, without
9、written permission of ITU. Rec. ITU-R M.1319-3 1 RECOMMENDATION ITU-R M.1319-3*,* The basis of a methodology to assess the impact of interference from a time division multiple access/frequency division multiple access (TDMA/FDMA) mobile-satellite service (MSS) space-to-Earth transmissions on the per
10、formance of line-of-sight fixed service receivers in the frequency range 1-3 GHz *(Questions ITU-R 201/4 and ITU-R 118/5) (1997-2000-2003-2010) Scope This Recommendation provides a methodology to assess the impact of interference from TDMA/FDMA mobile-satellite service (MSS) (space-to-Earth) transmi
11、ssions on the performance of line-of-sight (LoS) fixed service (FS) receivers in the frequency range 1-3 GHz. This methodology may be used for developing computer simulation tools for use in detailed MSS/FS coordination. The ITU Radiocommunication Assembly, considering a) that the frequency band 1 5
12、18-1 525 MHz is allocated to the mobile-satellite service (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) on a primary basis in all Regions; c) that the frequency band 1 5
13、25-1 530 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 2 170-2 200 MHz in all Regions and 2 160-2 170 MHz in Region 2 are
14、 allocated to the MSS (space-to-Earth) and the fixed service on a co-primary basis; e) that transmissions from MSS satellites could cause unacceptable interference to LoS fixed service receivers operating in these bands; f) that interference involves time-varying phenomena such as interference geome
15、try, propagation conditions, and MSS traffic; g) that simulation is the most common way to evaluate such interference; h) that the impact and acceptability of such interference in most cases can be assessed in detailed bilateral coordination by studying via computer simulation the C/N, C/I and C/(N
16、+ I ) statistics as described in Recommendation ITU-R M.1143; *This is a joint Radiocommunication Study Group 4 and 5 Recommendation, and any revision shall be undertaken jointly. *Further study is needed for MSS networks using code division multiple access (CDMA). 2 Rec. ITU-R M.1319-3 j) that assi
17、stance in using such tools is particularly needed by administrations in developing countries, recommends 1 that the methodology in Annex 1 should be used as a basis for developing computer simulation tools for use in detailed bilateral coordination between concerned parties to enable a detailed asse
18、ssment of the impact of interference from a TDMA/FDMA MSS satellite system in the 1-3 GHz MSS allocations to analogue and digital LoS fixed service systems, taking into account the specific characteristics of the MSS and fixed service systems concerned (see Notes 1, 2 and 3). NOTE 1 The application
19、of the methodology in this Recommendation will 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 con
20、cerned parties. NOTE 2 In countries where a large 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
21、that are likely to be most sensitive to interference. 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 a
22、greement between the concerned parties. NOTE 3 In the case of geostationary-satellite orbit (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
23、satellites may need to be considered when evaluating the impact of interference. Annex 1 1 Introduction Sharing between MSS and fixed service involves time varying phenomena such as interference geometry, propagation conditions, etc. Simulation is the most common way to evaluate interference between
24、 MSS and fixed service systems. The output of such simulations is typically in the form of C/I, C/N and C/(N + I ) statistics presented usually as a cumulative distribution function, for example as described in Recommendation ITU-R M.1143 (see Annex 3). The relevant baseband performance objectives f
25、or a given digital and analogue fixed service system can generally be translated into a required C/(N + I ) (see Note 1 below). For example for a digital fixed service system, the baseband specification is usually a bit-error ratio (BER) requirement not to be exceeded for a certain percentage of tim
26、e. The baseband BER requirement can, from reference curves such as those provided in Recommendation ITU-R SF.766 or actual modem specifications, be translated into a required Eb/N0value, which in turn can be translated into a C/(N + I ) requirement at the input to the receiver. In a similar way the
27、baseband requirements for analogue frequency division multiplex/frequency modulation (FDM/FM) and TV-FM fixed service systems in terms of total baseband noise or baseband S/N can be translated into a C/(N + I ) requirement at the input to the receiver. Rec. ITU-R M.1319-3 3 NOTE 1 While the performa
28、nce of radio-relay systems should, in principle, be related to a quantity that can be described as C/(N + I), the validity of such relationships depends on having the appropriate value for the total equivalent system noise, N. These equivalent radio-frequency performance objectives can be plotted on
29、 the cumulative distribution plots of C/(N + I ) and compared with the simulation curves of C/N and C/(N + I ) to assess if the interference from MSS satellites is acceptable or not. The method described herein, although it requires significant computer simulation is relatively straightforward to im
30、plement in software, since all calculations and comparisons are undertaken in the radio-frequency domain. The methodology herein should generally be used in the detailed coordination phase between administrations, when coordination is required and triggered in order to determine whether or not the i
31、nterference can be accepted in the context of actual fixed service system information and the relevant ITU-R performance and availability objectives. When assessing an MSS network using TDMA/FDMA, the aggregate interfering signal power within a reference bandwidth of 1 MHz (or less) for fixed statio
32、ns should be assumed to be generated only by the individual network under consideration, under the assumption that the emissions of these MSS systems would not be interleaved within any 1 MHz segment of spectrum. 2 Methodology 2.1 Generation of target C/(N + I ) requirements for fixed service system
33、 The relevant baseband performance objectives for a given digital and analogue fixed service system can generally be translated into a required C/(N + I ) as indicated below. Recommendation ITU-R F.3931specifies performance requirements for analogue FDM/FM fixed service systems in terms of total bas
34、eband noise in a given telephone channel for various percentages of time. These baseband requirements for the reference circuit can be translated through the standard C/N versus S/N FM equation into equivalent C/(N + I ) requirements. Recommendation ITU-R F.5552specifies performance requirements for
35、 analogue TV/FM fixed service systems in terms of required S/N in a given video channel for various percentages of time. These baseband requirements for the reference circuit can be translated through the standard C/N versus S/N FM equation into equivalent C/(N + I ) requirements. Recommendations IT
36、U-R F.634, ITU-R F.695, ITU-R F.696, ITU-R F.697 and ITU-R F.557 specify network performance objectives (NPO) (error performance objectives and availability) for the existing digital systems in high, medium and local grade of the integrated services digital network (ISDN) in terms of required BER fo
37、r various percentages of time. These baseband requirements for the reference circuit can be translated through standard reference curves provided in Recommendation ITU-R SF.766 into equivalent C/(N + I ) requirements. Generation of target C/(N + I ) requirements for new digital fixed service systems
38、 should be based on Recommendation ITU-R F.1668. 1Recommendation 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 exis
39、t for which this Recommendation would be applicable. 4 Rec. ITU-R M.1319-3 The actual fixed service receiver modem characteristics should be used, where available, in the translation from baseband performance objective to C/(N + I ). Where this information is not available, theoretical characteristi
40、cs from Recommendation ITU-R SF.766 can be used, and an implementation margin should be agreed between the parties. 2.2 Generation of C/I, C/N and C/(N + I ) statistics for fixed service system Step 1: Calculation at each time step of received carrier level, C, at each receive fixed service station
41、in a multi-hop fixed service route with multipath fading taken into account on that particular hop. a) The received carrier level, C, at each station is calculated from the associated transmit fixed service station e.i.r.p., the free space loss corresponding to the particular path length and multipa
42、th fading propagation loss applicable to that particular hop, the receive fixed service antenna gain and receive fixed service feed losses. b) Multipath fading is taken into account using a random fade depth predictor, whose output is consistent with the statistical distribution derived from the Rec
43、ommendation ITU-R P.530 multipath fading model. The random fade predictor generates fade depths at each relevant time step in the simulation, such that the statistical distribution of fades generated is consistent with the distribution predicted for that path. The fade depth predictor requires infor
44、mation on the path length, path inclination, frequency and a number of geoclimatic factors specified in the above Recommendation appropriate to the particular geographical location of the fixed service hop. The time step specified for the fade depth predictor can in general be different from that re
45、quired for interference assessment, since the latter is usually a more slowly varying process. For typical 2 GHz digital fixed service systems it is normally not necessary to include an allowance for other types of fading. c) In some cases, fixed service hops may not have first Fresnel Zone clearanc
46、e. In such cases, it is appropriate to add an additional loss factor to the free space loss and multipath fading loss. This factor should be based on measured data, where available. d) In cases where statistically valid measured propagation data is available for individual fixed service hops, this d
47、ata could be used in place of the propagation models given in a), b) and c) above, on agreement between the concerned parties. It may be possible in some cases (e.g. based on measured data), to take into account diurnal and/or seasonal variations in multipath fading propagation behaviour. e) Conside
48、ration should be given to including in the total noise, N, an allowance for intra-system and intra-service interference within the fixed service, as well as contributions from other co-primary (non-MSS) services (see Note 1 below). The value of this allowance should be determined by the concerned pa
49、rties. It should be noted that Recommendation ITU-R F.1094 specifies that the maximum allowable value of error performance and availability degradation to digital fixed service systems due to emissions from services sharing frequencies on a primary basis should not exceed 10% of NPO. NOTE 1 Included in the total equivalent noise, in addition to the contributions to account for thermal noise and receiver noise for the receivers, are factors to account for intra-service interference and additional factors depending on the type of fixed service system. For digital systems, factor
