1、 Rec. ITU-R SM.1633 1 RECOMMENDATION ITU-R SM.1633 Compatibility analysis between a passive service and an active service allocated in adjacent and nearby bands (2003) The ITU Radiocommunication Assembly, considering a) that the radio astronomy service (RAS), the Earth exploration-satellite service
2、(EESS) (passive) and space research service (SRS) (passive) are based on the reception of natural emissions at much lower power levels than are generally used in other radiocommunication services; b) that, due to these low received power levels, these passive services are generally more susceptible
3、to interference from unwanted emissions than other services; c) that general limits for spurious emissions contained in Appendix 3 of the Radio Regulations (RR) may not protect to the desired extent the passive services from interference; however, depending on the separation between the bands alloca
4、ted to the active and passive services actual spurious emission levels falling in a passive band may be lower; d) that general levels for emissions in the out-of-band (OoB) domain contained in Recom-mendation ITU-R SM.1541 may not protect operations of the passive services from interference; e) that
5、 there are various operational practices and mitigation techniques that can be used by the passive and active services to minimize the impact of interference on the passive services; f) that there may be practical and economic limitations on the applicability of these mitigation measures; g) that th
6、e burden of achieving compatibility between active and passive services should be equitably borne; h) that Recommendation 66 (Rev.WRC-2000) requests in recommends 5 that ITU-R “study those frequency bands and instances where, for technical or operational reasons, more stringent spurious emission lim
7、its than the general limits in Appendix 3 may be required to protect passive services such as radio astronomy, and the impact on all concerned services of implementing or not implementing such limits”; j) that Recommendation 66 (Rev.WRC-2000) requests in recommends 6 that ITU-R “study those frequenc
8、y bands and instances where, for technical or operational reasons, out-of-band limits may be required to protect passive services such as radio astronomy, and the impact on all concerned services of implementing or not implementing such limits”; k) that the situations of greatest potential difficult
9、y to the passive services are those listed in Table 1, 2 Rec. ITU-R SM.1633 recommends 1 that the methodology in Annex 1 should be used in conducting compatibility analysis between a passive service and an active service operating in allocated bands listed in Table 1; 2 that other methodologies that
10、 lead to a compatibility solution could be used where appropriate; 3 that the results of band-by-band studies, described in Annexes 2 through 21, should be considered in developing solutions to interference problems between the indicated services. TABLE 1 Reference list of relevant frequency bands f
11、or band-by-band studies Passive service band Active service band Annex 1 400-1 427 MHz (RAS) 1 452-1 492 MHz (BSS)2 1 400-1 427 MHz (EESS) 1 350-1 400 MHz (Radiolocation) 3 1 400-1 427 MHz (EESS/RAS) 1 525-1 559 MHz (MSS)4 1 610.6-1 613.8 MHz (RAS) 1 559-1 610 MHz (RNSS)5 1 610.6-1 613.8 MHz (RAS) 1
12、 613.8-1 626.5 MHz (MSS) 6 1 610.6-1 613.8 MHz (RAS) 1 525-1 559 MHz (MSS)7 2 690-2 700 MHz (RAS) 2 655-2 690 MHz (BSS, FSS)8 10.6-10.7 GHz (EESS) 10.7-10.95 GHz (FSS)9 10.6-10.7 GHz (RAS) 10.7-10.95 GHz (FSS)10 21.2-21.4 GHz (EESS) 20.2-21.2 GHz (MSS, FSS)11 22.21-22.5 GHz (RAS) 21.4-22 GHz (BSS)12
13、 23.6-24 GHz (EESS) 22.55-23.55 GHz (ISS) 13 31.3-31.5 GHz (EESS) 30-31 GHz (FSS, MSS)14 31.3-31.5 GHz (EESS) 31.0-31.3 GHz (FS) 15 31.5-31.8 GHz (EESS) 31.8-33.4 GHz (FS) 16 31.5-31.8 GHz (EESS) 31.8-33.4 GHz (RN) 17 42.5-43.5 GHz (RAS) 41.5-42.5 GHz (BSS, FSS)18 50.2-50.4 GHz (EESS) 47.2-50.2 GHz
14、(FSS)19 50.2-50.4 GHz (EESS) 50.4-51.4 GHz (FSS, MSS)20 52.6-52.8 GHz (EESS) 51.4-52.6 GHz (FS) 21 RNSS: radionavigation satellite service. ISS: inter-satellite service. FS: fixed service. Rec. ITU-R SM.1633 3 Annex 1 Methodology 1 General The following general methodology defines a systematic means
15、 for deriving mutually acceptable compatibility criteria between operators of active and passive services operating in their allocated bands. The flow diagram (Fig. 1) summarizes the methodology with each individual step described in detail in 2 of this Annex. As the procedure is iterative, several
16、cycles might be required before a solution is found. The first step is to determine the transmission parameters of the active service (box (i). The starting point is the worst-case scenario that is used to determine whether there is the potential for detrimental interference to passive services by a
17、ny and all types of active services operating in an adjacent or nearby band. This worst-case power level could often be determined from existing regulatory limits (box (1), such as the pfds found in RR Article 21. Such regulatory limits for the power transmitted by the active service must then be us
18、ed to determine the worst-case level of unwanted emission into the passive band (box (ii). The following step is to determine if this worst-case interference level is higher than the passive service interference threshold for the band under consideration (diamond (a). These threshold levels are give
19、n in various ITU-R Recommendations (box (2) such as Recommendations ITU-R RA.769, or ITU-R SA.1029. If this interference threshold is higher than the worst-case level of unwanted emissions in the band, then there is no adverse impact to the passive service operations. In this case the methodology fo
20、llows the “Yes” line and the process terminates. At this point, as at all other end points in the methodology, the assumptions used to achieve the end point form the technical basis for a compatible working arrangement between the active and passive services involved. How these technical assumptions
21、 and their resulting conclusions are used is a regulatory exercise and is beyond the technical scope of this Recommendation. However, for the case of diamond (a), if the interference is assessed to be greater than the passive service criteria, then it is necessary to follow the “No” branch to diamon
22、d (b). On the first iteration, no new information is available so the path continues to box (iii). On later iterations, the threshold in diamond (b) may be different from the passive service criteria used in diamond (a) as a consequence of modified or additional parameters and burden sharing. These
23、modified or additional parameters may result from diamonds (c), (d) or (e). Diamond (b) allows a further assessment whether compatibility has been achieved. If such is the case the process follows along the “Yes” branch, and the procedure ends. If such is not the case, the discrepancy has to be asse
24、ssed, whereby in reaching diamonds (c), (d) or (e) the following alternatives should be investigated: refine the emission parameters of the active service such as the actual system parameters, available prime power, etc. and/or; refine the reception parameters in the passive band, and/or; develop fu
25、rther mitigation techniques for both the active and passive services, which may include both alternatives (a) and (b). 4 Rec. ITU-R SM.1633 1633-01FIGURE 1Process for the evaluation of adjacent and nearby bandoperation of passive and active servicesTransmitter emission(i)Existing ITU documents(1)Int
26、erference power(ii)(a)Interferencepower = Passive servicecriteriaEnd(a)End(b)Assess discrepancy(iii)(c)Can the emissionparametersbe refined?New information(4)(d)Can the receptionparameters in passive bandbe refined?(e)Is the application ofmitigation techniquesfeasibleExisting ITU documents(2)Evaluat
27、e interference(3)New information(5)New information(6)End(c)(b)Interference= ThresholdConsultative solution(iv)NoNoNoNoNoNoYesYesYesYesYesRec. ITU-R SM.1633 5 When during the assessment of discrepancies, as indicated in box (iii), it is shown that the divergence between the two levels is large, then
28、it is clear that the assumptions used in the first iteration are insufficient to resolve the issue and more detailed assumptions about the characteristics and operations of both services must be made. However, if the divergence is small, it may be possible to modify slightly one of the underlying as
29、sumptions so as to enable converging on a solution on the next iteration. A review of the data at hand may suggest what additional assumptions might be beneficial. From this consideration, either one or more of the active service parameters, passive service parameters, the compatibility criteria or
30、possible mitigation methods can be considered for modification in successive iterations. As many iterations will take place as necessary to either completely close the gap or to have exhausted all potential solutions. If all possible solutions have been exhausted and no compatible operation appears
31、to be possible, then the method ends with a “consultative solution”. This implies that the only possible solution is for a specific active system to consult with a specific passive service system operator, in order to achieve a one-to-one solution, if that is possible. Specifics of such a consultati
32、ve solution are outside the purview of this Recommendation. This methodology only addresses the potential interference from a single active service operating in its allocated band. Noting that EESS (passive) may receive interference simultaneously from multiple services, additional consideration may
33、 be required to account for the aggregate effects of multiple active services. 2 Detailed description of the flow chart 2.1 Box (1): Existing ITU documents This box refers to documents that may be relevant for determining transmitter emissions. The following Articles of the RR and ITU-R Recommendati
34、ons and Reports are relevant to determining transmitter power that may fall into passive bands, and are provided for reference. These regulations and recommendations are to be used as the starting point in the evaluation of potential active service unwanted emissions into passive service bands. Radi
35、o Regulations Articles 1, 5, 21, 22, Appendix 3. Recommendations ITU-R F.758: Considerations in the development of criteria for sharing between the terrestrial fixed service and other services ITU-R F.1191: Bandwidths and unwanted emissions of digital fixed service systems ITU-R SM.326: Determinatio
36、n and measurement of the power of amplitude-modulated radio transmitters ITU-R SM.328: Spectra and bandwidth of emissions ITU-R SM.329: Unwanted emissions in the spurious domain ITU-R SM.1446: Definition and measurement of intermodulation products in transmitter using frequency, phase, or complex mo
37、dulation techniques 6 Rec. ITU-R SM.1633 ITU-R SM.1539: Variation of the boundary between the out-of-band and spurious domains required for the application of Recommendations ITU-R SM.1541 and ITU-R SM.329 ITU-R SM.1540: Unwanted emissions in the out-of-band domain falling into adjacent allocated ba
38、nds ITU-R SM.1541: Unwanted emissions in the out-of-band domain. Some data may be needed beyond what these Recommendations provide. This includes: the duty cycle of the systems; the geographic distribution and densities of the emitters including deployment densities; the antenna aiming or scanning f
39、or radiodetermination systems or Earth-to-space transmissions; the beam coverage for space-to-Earth transmissions; relevant spectral masks; and antenna patterns. Not all of the required data may be available. for all items listed above. Assumptions may be necessary for some parameters. Other informa
40、tion such as deployment may require the development of models. 2.2 Box (2): Existing ITU documents This box refers to documents relevant to the selection of the appropriate passive service criteria for protection from interference. The various passive service criteria, each developed by the working
41、party responsible for the respective passive services, serve as the input of diamond (a) on the flowchart. These Recommendations have been developed, over time, in order to assist other working parties dealing with active services in evaluating the potential for interference from their respective se
42、rvices into the passive services. The list of Recommendations to be considered is as follows: Recommendations ITU-R RA.769: Protection criteria used for radioastronomical measurements ITU-R RA.1513: Levels of data loss to radio astronomy observations and percentage-of-time criteria resulting from de
43、gradation by interference for frequency bands allocated to the radio astronomy on a primary basis ITU-R SA.1028: Performance criteria for satellite passive remote sensing ITU-R SA.1029: Interference criteria for satellite passive remote sensing. 2.3 Box (3): Evaluate interference The function of thi
44、s box is to allow for the passive service to generate a new sharing criterion based on the information provided from boxes (5) and (6). As an example, lower side lobe levels might be assumed than the 0 dBi receive antenna gain figure currently assumed for the RAS. If this were the case, the process
45、of re-calculating the sharing criteria would be done in box (3). Rec. ITU-R SM.1633 7 To evaluate interference from non-GSO FSS systems to stations in the RAS, the methodology of Recommendation ITU-R S.1586 should be used. Likewise, to evaluate interference from non-GSO MSS and RNSS systems to stati
46、ons in the RAS, the methodology of Recommendation ITU-R M.1583 should be used. 2.4 Boxes (4), (5) and (6): New information The function of the box is to accommodate new information brought into the sharing study while it proceeds through multiple iterations. An example of such a situation would be t
47、he making usage of RR Appendix 4 information submitted to the Radiocommunication Bureau (BR) in box (4) to justify the use of an in-band pfd less than the regulatory figure. Other information may consist of filter or antenna information in any of boxes (4), (5) and (6) that is brought into the proce
48、ss in order to close the gap. New information may also consist of additional input not considered previously, such as specific ITU-R Recommendations, regional recommendations, or regional standards. Examples for the relevant boxes are as follows: Box (4) At higher frequencies, transmit antenna patte
49、rns can have a significantly narrower beamwidth in order to maximize the power in a limited service area so as to increase throughput and overcome atmospheric effects. As a result, the majority of the surface of the Earth may receive an unwanted emission pfd level that is well below the detrimental level of the passive service. Instead of having the level applicable over the entire surface of the Earth, it may be possible to relax the level over a fraction of the Earths surface. As a result, the probability that an RAS station will receive detrimental
