1、 Rep. ITU-R M.2041 1 REPORT ITU-R M.2041 Sharing and adjacent band compatibility in the 2.5 GHz band between the terrestrial and satellite components of IMT-2000 (2003) TABLE OF CONTENTS Page 1 Introduction 3 2 Sharing and adjacent band compatibility methods. 3 2.1 Interference mechanisms 3 2.2 Mini
2、mum coupling loss (MCL) and Monte Carlo approaches. 6 2.3 Propagation models 7 3 Co-frequency sharing conclusions . 7 4 Adjacent band summary results 8 5 Adjacent band conclusions and discussions . 13 5.1 Overall conclusions 13 5.2 Feasibility of adjacent band compatibility for SRI-E . 17 5.3 Feasib
3、ility of adjacent band compatibility for S-DMB 18 6 Glossary and abbreviations. 19 Annex 1 System parameters 20 1 T-IMT-2000 system parameters . 20 2 Satellite radio interface E (SRI-E) system parameters . 23 3 S-DMB system parameters. 27 Annex 2 Detailed sharing and compatibility analysis. 35 1 Int
4、erference from MSS satellites into T-IMT-2000 . 35 2 Interference from MSS MES into T-IMT-2000 . 47 3 Interference from T-IMT-2000 into MSS satellites . 59 4 Interference from T-IMT-2000 into MSS MES . 67 5 Sensitivity analysis for the SRI-E. 79 NOTE Concerning the satellite component of IMT-2000, t
5、his Report covers some current and potential IMT-2000 satellite radio interfaces. 2 Rep. ITU-R M.2041 1 Introduction WRC-2000 identified three different blocks of additional spectrum for IMT-2000, including the band 2 500-2 690 MHz. The band 2 500-2 690 MHz is currently allocated on a primary basis
6、to several space services, the fixed service and the mobile service. This Report restricts its scope to the interference between the MSS and terrestrial component of IMT-2000. This Report uses the relevant parameters needed in interference studies at the date of publication. It should be noted that
7、the parameters assumed in this Report for the IMT-2000 terrestrial system are those of IMT-2000 CDMA direct spread/CDMA TDD (referred to hereafter in this Report as T-IMT-2000); no other terrestrial IMT-2000 radio interfaces have been considered because the current studies only consider that interfa
8、ce. The interference problems are investigated by deterministic and statistical approaches, for the different scenarios. This Report gives technical conclusions regarding the necessary guardbands between T-IMT-2000 and the MSS in the band 2 500-2 690 MHz. Since these conclusions are based on paramet
9、ers correct at the date of publication and predicted deployment scenarios, it should be noted that any changes in parameters, for example, in the T-IMT-2000 emission masks, would require the conclusions of this Report to be reconsidered. 2 Sharing and adjacent band compatibility methods 2.1 Interfer
10、ence mechanisms 2.1.1 Interference paths for S-IMT-2000/T-IMT-2000 sharing and compatibility assessments The various interference paths can be categorized in a number of ways. The approach selected is based on the wanted or interfering system and whether the interference path is the satellite compon
11、ent (including eventually terrestrial repeaters) or the terrestrial component. This approach was selected as the satellite IMT-2000 (S-IMT-2000) direction (uplink or downlink) determines the approach to modelling. The result is four main interference paths, as shown in Table 1 and Figs. 1 to 4. TABL
12、E 1 Interference paths Interference path MSS downlink at 2 520 MHz MSS uplink at 2 670 MHz T-IMT-2000 wanted MSS interfering A B T-IMT-2000 interfering MSS wanted D C Rep. ITU-R M.2041 3 Rap 2041-01A3A1A2A4MSS satelliteSatellite downlinkIn band TxMobileearthstation(MES)Terrestrialrepeater(TR)Base st
13、ation(BS)TerrestrialUser equipment(UE)FIGURE 1Interference path A2 500-2 520 MHzInterference path:A1: MSS UEA2: MSS BSA3: TR UEA4: TR BSRap 2041-02B1B2MSS satelliteSatellite uplinkMESBSTerrestrialUEFIGURE 2Interference path B2 670-2 690 MHzInterference path:B1: MES UEB2: MES BS4 Rep. ITU-R M.2041 Ra
14、p 2041-03C1C2MSS satelliteSatellite uplinkMESBSTerrestrialUEsInterference path:C1: UE MSSC2: BS MSSFIGURE 3Interference path C2 670-2 690 MHzRap 2041-04D2, D4D1, D3MSS satelliteSatellite downlinkIn bandTxMESTRBSTerrestrialUEsInterference path:D1: UE MES (receiving from satellite)D2: BS MES (receivin
15、g from satellite)D3: UE MES (receiving from TR)D4: BS MES (receiving from TR)FIGURE 4Interference path D2 500-2 520 MHzRep. ITU-R M.2041 5 2.2 Minimum coupling loss (MCL) and Monte Carlo approaches In this Report, two approaches have been used so far to assess interference between two systems. a) Th
16、e first one, the minimum coupling loss (MCL), allows computation, for a given system (a given set of transmitter and receiver parameters) of the minimum propagation loss (and hence derivation of the minimum separation distance) and/or the minimum adjacent band isolation (and hence derivation of the
17、minimum guardband). For 3GPP compliant systems (terrestrial or satellite) operating with the same bandwidth, the adjacent band isolation is expressed by the adjacent channel interference ratio (ACIR), as explained below. It should be noted that the ACIR concept is useful when standard frequency carr
18、ier separations of 5, 10 or 15 MHz are envisaged. In other cases, the use of Tx/Rx spectrum masks is necessary. The MCL between an interfering transmitter (Tx) and a victim receiver (Rx) is defined as: )dBm/Ref.Bw()dBi()dBi()Ref.Bw/dBm(thresholdceinterferenRgainantennaRgainantennaTpowerTMCLxxxx+=In
19、the case of a minimum separation distance calculation, Dmin: )(minDn modelPropagatioMCL = In the case of a minimum guardband calculation, fseparation: )()(separationminfACIRDmodelnPropagatioMCL = The ACIR is defined as: ACSACLRACIR111+= (in linear terms) ACLR is the adjacent channel leakage ratio of
20、 the interfering transmitter (i.e. the out-of-band power ratio falling into the adjacent channel), and ACS is the adjacent channel selectivity (i.e. the power received in the adjacent channel after the input filter) of the victim receiver. However, in T-IMT-2000 systems, the interference usually res
21、ults in loss of capacity and/or of coverage. The assessment of the impact of interference therefore requires in some cases a simulation over a large number of transmitters and receivers and MCL may not be adequate to investigate this loss. In addition, MCL does not model power control or dynamic sit
22、uations, which may be determining for some scenarios, such as for example, those involving user terminals as a victim. b) The second approach is the Monte Carlo simulation, which gives a probability of interference for the given set of parameters and a deployment and power control model. The accepta
23、ble interference probability used in Monte Carlo studies will depend on the scenario under consideration. For example, in the case of interference between MES and the terrestrial UE, the maximum acceptable interference probability for terrestrial IMT-2000 CDMA direct spread is considered to be 2%. 6
24、 Rep. ITU-R M.2041 The Seamcat1Monte Carlo tool was used in most of the Monte Carlo simulations presented in that Report. The assumptions used in the Monte Carlo simulations are detailed in Annex 2, and are based on work in ITU-R. Additional information is also included alongside the reported compat
25、ibility studies. It is understood that any one of the approaches described above is not sufficient alone to describe in detail the interference problem, and to conclude on the problem of guardbands. The following points are relevant to the comparison of deterministic and statistical approaches: The
26、MCL method is useful for an initial assessment of frequency sharing, and is suitable for fairly “static” interference situations (e.g. fixed links vs. mobile base stations). It can however be pessimistic in some cases. The Monte Carlo method will generally give more realistic results. It is however
27、complex to implement and will only give accurate results if the probability distributions of all the input parameters are well known. 2.3 Propagation models The propagation models to be used for deriving the separation distances with MCL as well as with Monte Carlo approaches are the following: For
28、space-to-Earth and Earth-to-space paths Free space path loss plus attenuation due to gaseous absorption as defined in Recommendation ITU-R P.676. When a very high accuracy of the results is not required, the gaseous/rain attenuation can be neglected at frequencies below 3 GHz. For terrestrial paths
29、For distances 20 km, Recommendation ITU-R P.452 for smooth Earth. Typically this is used for non-co-located systems, e.g. for geographic separation. 3 Co-frequency sharing conclusions When considering the sharing of the same frequency band between the terrestrial component of IMT-2000 and the MSS, t
30、he detailed analysis (see Annex 2) shows that such sharing is not feasible over the same geographical area. Consequently, Radiocommunication Study Group 8 came to the conclusion that co-frequency sharing is not feasible for networks operating in the same geographical area. The feasibility of co-freq
31、uency sharing was reviewed as part the studies undertaken in this Report. The conclusions are summarized below for each of the two MSS systems considered: 1http:/www.ero.dk/971f102b-c3b2-42d4-a186-82162f695ee9.W5Doc. Rep. ITU-R M.2041 7 For SRI-E In general, co-frequency sharing between the satellit
32、e radio interface (SRI)-E satellite component and the terrestrial component was found to be difficult, with some paths that would result in extremely high levels of interference. In particular co-frequency operation of both satellite uplink and downlink in a band with terrestrial systems would not b
33、e feasible based on the assumptions and modelling in this study. This is primarily due to high levels of aggregate interference from T-IMT-2000 systems into the S-IMT-2000 uplink. There is some potential for S-IMT-2000 downlink operation co-frequency with T-IMT-2000 systems, but this would require l
34、arge separation distances between the S-IMT-2000 service area and the T-IMT-2000 service area. The most problematic paths were from T-IMT-2000 into S-IMT-2000, that is: path C: from T-IMT-2000 (either uplink or downlink) into S-IMT-2000 satellite at 2 670-2 690 MHz path D: from T-IMT-2000 (either up
35、link or downlink) into S-IMT-2000 MES at 2 500-2 520 MHz. In general paths A and B, from S-IMT-2000 into T-IMT-2000 resulted in lower interference levels. For S-DMB As for SRI-E, the co-frequency sharing is not feasible over the same geographical area. When considering interference from the satellit
36、e, a satellite antenna discrimination over the T-IMT-2000 service area around 20-25 dB is necessary. Conversely, the co-channel protection of the satellite reception from terrestrial interference would require a satellite antenna discrimination of 25 to 40 dB over the T-IMT-2000 service area, depend
37、ing on deployment assumptions, and the nature of the interferers (mobile station (MS) or BS). The interference of the satellite-digital multimedia broadcast (S-DMB) terrestrial repeaters into T-IMT-2000 is an additional factor which impedes co-frequency co-located operation of S-DMB and T-IMT-2000.
38、4 Adjacent band summary results The adjacent band compatibility results are summarized in Table 2. The systems characteristics and study results are detailed in Annexes 1 and 2. In Table 2 results are given either in term of frequency carrier spacing or in term of frequency guardbands. A scenario is
39、 considered not feasible when guardbands exceed 15 MHz. Concerning IMT-2000 CDMA TDD simulations, results are highly dependent on the deployment assumptions. 8 Rep. ITU-R M.2041 TABLE 2 Adjacent band compatibility results Scenario Interferer victim S-DMB SRI-E 1 (Path A1) Sat down UE IMT-2000 CDMA d
40、irect spread down 2 520 MHz Feasible with standard 5 MHz carrier spacing Feasible without any guardband 2 (Path A1) Sat down UE Rx IMT-2000 CDMA TDD 2 520 MHz Feasible with standard 5 MHz carrier spacing Feasible without any guardband(1) 3 (Path A2) Sat down BS IMT-2000 CDMA direct spread up 2 520 M
41、Hz Feasible with a carrier spacing of 5.3 MHz (could be improved by optimized satellite filtering techniques) Feasible without any guardband 4 (Path A2) (Sat down BS Rx IMT-2000 CDMA TDD 2 520 MHz Feasible with a carrier spacing of 5.3 MHz (could be improved by optimized satellite filtering techniqu
42、es) Feasible without any frequency guardband(1)5 (Path A3) TR IMT-2000 CDMA direct spread down 2 520 MHz Feasible with standard 5 MHz carrier spacing (no guardband required) Not applicable: No terrestrial repeaters with SRI-E 6 (Path A3) TR MS Rx IMT-2000 CDMA TDD 2 520 MHz Feasible with standard 5
43、MHz carrier spacing (no guardband required) Not applicable: No terrestrial repeaters with SRI-E 7 (Path A4) TR IMT-2000 CDMA direct spread up 2 520 MHz Not feasible: required carrier spacing greater than 20 MHz Not applicable: No terrestrial repeaters with SRI-E 8 (Path A4) TR BS Rx IMT-2000 CDMA TD
44、D 2 520 MHz Required carrier spacing depends on IMT-2000 CDMA TDD deployment. T-IMT-2000 coexistence studies results apply Not applicable: No terrestrial repeaters with SRI-E Rep. ITU-R M.2041 9 TABLE 2 (continued) Scenario Interferer victim S-DMB SRI-E 9 (Path B1) MES Sat up UE IMT-2000 CDMA direct
45、 spread down 2 670 MHz The standard 5 MHz carrier spacing is appropriate Feasible: does not require frequency guardband 10 (Path B1) MES Sat up UE Rx IMT-2000 CDMA TDD 2 670 MHz The standard 5 MHz carrier spacing is appropriate Feasible: does not require frequency guardband 11 (Path B2) MES Sat up B
46、S IMT-2000 CDMA direct spread up 2 670 MHz Feasible with standard 5 MHz carrier spacing for all S-DMB terminals, except for S-DMB portable terminals operating in rural cells, for which the following specific operating constraints apply: a 10 MHz carrier spacing (5 MHz guardband) shall apply, or the
47、portable S-DMB terminal is forbidden to transmit to the satellite within terrestrial cells where the adjacent 5 MHz channel is operated. In this case, the standard 5 MHz carrier spacing is appropriate Feasible: does not require frequency guardband 12 (Path B2) MES Sat up BS Rx IMT-2000 CDMA TDD 2 67
48、0 MHz Feasible with standard 5 MHz carrier spacing Feasible: does not require frequency guardband 13 (Path C1) UE IMT-2000 CDMA direct spread up Sat up 2 670 MHz Feasible with a carrier spacing of 5 MHz (no guardband required) Feasible with a 1 MHz guardband 10 Rep. ITU-R M.2041 TABLE 2 (continued)
49、Scenario Interferer victim S-DMB SRI-E 14 (Path C1) UE Tx IMT-2000 CDMA TDD Sat up 2 670 MHz Feasible with a carrier spacing of 5 MHz (no guardband required) Feasible: does not require frequency guardband 15 (Path C2) BS IMT-2000 CDMA direct spread down Sat up 2 670 MHz Feasible with a carrier spacing of 5 MHz Guardband exceeds 7 MHz. See also Annex 2, 5 for sensitivity analysis 16 (Path C2) BS Tx IMT-2000 CDMA TDD Sat up 2 670 MHz Feasible with a carrier spacing of 5 MHz Feasibl
