1、 Rep. ITU-R M.2112 1 REPORT ITU-R M.2112 Compatibility/sharing of airport surveillance radars and meteorological radar with IMT systems within the 2 700-2 900 MHz band (2007) 1 Introduction Recognizing need for additional spectrum for IMT systems, the band 2 700-2 900 MHz was identified as a candida
2、te band for IMT systems, presenting potential advantages for IMT. However, as described in the following table, the band 2 700-2 900 MHz is allocated worldwide on a primary basis to radionavigation service, used for air surveillance radars (ASR), including radars providing air surveillance and air t
3、raffic control, as well as meteorological radars that are afforded equal status to the aeronautical radionavigation system (ARNS) for operation in this band under RR No. 5.423. Allocation to services Region 1 Region 2 Region 3 2 700-2 900 AERONAUTICAL RADIONAVIGATION 5.337 Radiolocation 5.423 5.424
4、5.423 In the band 2 700-2 900 MHz, ground-based radars used for meteorological purposes are authorized to operate on a basis of equality with stations of the aeronautical radionavigation service. 5.337 The use of the bands 1 300-1 350 MHz, 2 700-2 900 MHz and 9 000-9 200 MHz by the aeronautical radi
5、onavigation service is restricted to ground-based radars and to associated airborne transponders which transmit only on frequencies in these bands and only when actuated by radars operating in the same band. 5.424 Additional allocation: in Canada, the band 2 850-2 900 MHz is also allocated to the ma
6、ritime radionavigation service, on a primary basis, for use by shore-based radars. Since ARNS radars perform a safety-of-life service as specified by No. 4.10 of the Radio Regulations (RR), harmful interference must be avoided. Thus, any potential new service introduced in this band must be thorough
7、ly analyzed to ensure that interference does not exceed the radar protection criteria as given in Recommendation ITU-R M.1464. It should be noted that this band was already considered as a potential extension band for IMT-2000 at WRC-2000 and that, compatibility studies performed at that time, based
8、 on available assumptions, concluded on the non-compatibility of co-channel operation between IMT-2000 and radiodetermination services. The present Report provides compatibility analysis between ASR and meteorological radars and IMT systems operating in the 2 700-2 900 MHz band with new assumptions
9、and systems characteristics. 2 Rep. ITU-R M.2112 2 Compatibility analysis This Report contains two sharing studies given in Annex 1 (Study A) and Annex 2 (Study B). Study A considers compatibility analysis between IMT systems and radars in both interference scenario from IMT stations to radars and r
10、adars to IMT stations. It first provides simulations that quantify interference levels from meteorological radars to IMT networks and discusses proposed interference mitigation techniques, including frequency dependent rejection analysis. Secondly, it provides a compatibility analysis of interferenc
11、e from IMT networks to ASR and meteorological radars that describe technical matters related to the methodology, protection criteria, and mitigation techniques used to analyze potential compatibility. Study A (Annex 1) contains the following Appendices: Appendix 1 to Annex 1 summarizing the characte
12、ristics and assumptions used for the studies and taken from various ITU-R Recommendations (see 3) (Radar and IMT system characteristics, interference criterion, propagation scenarios, simulation methodologies and interference mitigation techniques). Appendix 2 to Annex 1 providing results of IMT sha
13、ring studies with ASRs Type A, B and C as described in Recommendation ITU-R M.1464. Appendix 3 to Annex 1 presenting results of IMT sharing studies with meteorological radars Type G as described in Recommendation ITU-R M.1464. Appendix 4 to Annex 1 presenting results of studies that show what the im
14、pact of ASR and meteorological radar operations have upon IMT systems. Study B (Annex 2) considers compatibility analysis between IMT systems and radars in both interference scenario from IMT stations to radars and radars to IMT stations. It provides simulations that quantify interference levels fro
15、m IMT networks to meteorological and ARNS radars, including effects of mitigation techniques and frequency dependent rejection. Secondly, it provides a detailed analysis of interference to IMT networks from ASR and meteorological radars. Radar and IMT characteristics are described, as well as the me
16、thodology for the various simulations. Study B contains the following Appendices: Appendix 1 to Annex 2 describing the clutter loss modifications to the propagation model for transmitters of low height. Appendix 2 to Annex 2 containing results on IMT base station front end filters, allowing increase
17、 of the frequency dependent rejection (FDR). Appendix 3 to Annex 2 presenting a detailed analysis of interference from radars to IMT networks. 3 References 1 Recommendation ITU-R M.1464 Characteristics of radiolocation radars, and characteristics and protection criteria for sharing studies for aeron
18、autical radionavigation and meteorological radars in the radiodetermination service operating in the frequency band 2 700-2 900 MHz. 2 Recommendation ITU-R M.1461 Procedures for determining the potential for interference between radars operating in the radiodetermination service and systems in other
19、 services. Rep. ITU-R M.2112 3 3 Recommendation ITU-R P.452-12 Prediction procedure for the evaluation of microwave interference between stations on the surface of the Earth at frequencies above about 0.7 GHz. 4 Report ITU-R M.2039 Characteristics of terrestrial IMT-2000 systems for frequency sharin
20、g/interference analyses. 4 Conclusion From the studies attached to this Report, it can be concluded that IMT and radiodetermination services in the band 2 700-2 900 MHz operating on a co-frequency basis are not compatible, presenting large required separation distances of several hundred of kilomete
21、rs, even applying the possible mitigation techniques considered to date. Assuming a frequency management that would consider a frequency separation between IMT systems and radiodetermination radars, filtering characteristics of both IMT and radars could provide a certain interference level decrease
22、(FDR of 50 dB). In this case, for meteorological radars (type G) the analysis still shows high separation distances and hence a non-compatibility in most of the cases: macro and micro IMT cells with or without potential practical mitigation techniques; pico cells without mitigation techniques. For t
23、he other type of radars considered in the study (ASR, type A), the analysis shows that the separation distances would be decreased to tens of kilometers for pico cells and, provided that sufficient clutter attenuation could be ensured by adequate placing of the station, for IMT-Advanced micro cells.
24、 The following mitigation techniques were considered: Improved filtering of IMT emissions from 50 to 90 dB: In this case, filtering could provide an additional interference reduction of about 15 dB when considering frequency separation of 10 MHz between IMT stations and radars. In this case, separat
25、ion distances would be further reduced. It was shown that for IMT-Advanced micro cells, the required separation distance is decreased down to 3 km for ASR radar whereas it still remains beyond 100 km for meteorological radars. This improved filtering could further reduce the interference (with FDR u
26、p to 90 dB) if considerably larger frequency separation between IMT stations and radars are applied. However, in this case, it could be considered that the required frequency separation would not be compatible with successful operation of radars and IMT in a 200 MHz band. IMT Sector blanking: This m
27、itigation technique only applies to sectorised IMT macro cells and could potentially reduce the interference up to about 30 dB, resulting in separation distances of about 150 km for meteorological radars and 10 km for ASR radars. However, this mitigation technique will be less efficient in a scenari
28、o with multiple radars present operating in the same frequency range. Temporary muting: This mitigation technique could theoretically reduce the interference by about 50 dB but was shown as being impractical since it is unlikely that IMT stations could either sense the radar antenna main beam direct
29、ion or to receive this information from the radar networks. It should be stressed that the potential use of the 2 700-2 900 MHz band by IMT should be limited to IMT systems downlink to avoid any possible interference from IMT handset/terminal that could not be controlled by the network in case of ma
30、lfunction. This leads to the point that uplink would have to be accommodated in another band. 4 Rep. ITU-R M.2112 In addition, due to frequency separation constraints with radars, there would be a limit on the possible bandwidth available for IMT connections in this band, acknowledging that it would
31、 be challenging to manage 20 MHz IMT bandwidth between radar frequencies, depending on radar deployment density, and impossible to handled 100 MHz bandwidth in this 200 MHz frequency band. It should also be noted that, in addition to necessary frequency separation between IMT and radars, radar frequ
32、ency tolerance given in RR Appendix 2 are approximately of about 3.5 MHz in the 2 700-2 900 MHz band which would effectively require a frequency separation higher than 15 MHz. Also, one should consider that a number of radars in this frequency band operate on 2 fixed frequencies or in a frequency ho
33、pping mode. Should the 2 700-2 900 MHz band be considered for use by IMT systems, such use could be constrained or even impossible depending on the radar deployment density. In countries with low radar deployment, there could be frequency ranges and geographical areas where some types of IMT systems
34、 downlink may be accommodated. It should be highlighted that possible frequency separation management between radars and IMT systems in this band would restrict future radar deployment that could be needed for improving radar networks coverage required for safety of life and security purposes. 5 Def
35、initions and abbreviations 5.1 Definition No new definitions introduced. 5.2 Abbreviations ACLR Adjacent channel leakage power ratio ACS Adjacent channel selectivity ADC Analog to digital converter AGC Automatic gain control ARNS Aeronautical radionavigation system ASR Air surveillance radar BER Bit
36、 error rate CDF Cumulative distribution function CDMA Code division multiple access DFS Dynamic frequency selection FDR Frequency dependent rejection FEC Forward error correction GHz Gigahertz IMT International mobile telecommunications IPS Integrated propagation system (computer model) ITU Internat
37、ional Telecommunication Union Rep. ITU-R M.2112 5 kHz Kilohertz km Kilometres LNA Low noise amplifier LoS Line-of-sight MHz Megahertz NLOS Non line-of-sight NTIA National Telecommunications and Information Administration OFDM Orthogonal frequency division multiplexing OFR Off tune rejection OoB Out
38、of band OTR On tune rejection PRR Pulse repetition rate SF Spreading factor SDMA Spatial division multiple access UMTS Universal mobile telecommunications system WMO World Meteorological Organization Annex 1 Study A Compatibility of air surveillance radars and meteorological radar with IMT systems w
39、ithin the 2 700-2 900 MHz band 1 Introduction The band 2 700-2 900 MHz is allocated worldwide on a primary basis to ASR, including radars providing air surveillance and air traffic control. In addition, meteorological radars are afforded equal status to the ASR for operation in this band. Since ASR
40、radars perform a safety service as specified by RR No. 4.10, harmful interference must be avoided. Any other service introduced in this band must be thoroughly analyzed to ensure that interference is kept at acceptable levels and to prevent any compromise in the quality of radar services in those co
41、untries using this band for the ASR and meteorological radars. About 40 administrations worldwide have been identified that operate meteorological radars in the band 2 700-2 900 MHz for both air surveillance and meteorological radar operations. While some administrations have low numbers of systems
42、in operation, the use of radars in the 2 700-2 900 MHz band near the borders of neighbouring countries must be considered as well when determining the availability of spectrum by coordination in case large separation distances are required. For many administrations that currently do not use the band
43、 or use the band lightly, future additional air surveillance radars and meteorological radars should be taken into account. 6 Rep. ITU-R M.2112 However, the importance of additional spectrum for IMT has been recognized, and the band 2 700-2 900 MHz has a number of advantages for IMT: this band is ne
44、ar the bands already identified for IMT-2000, which may facilitate the use of some of the base and mobile station hardware as in the band 2.5-2.69 GHz and would present similar propagation conditions; it is adjacent to the IMT-2000 extension band 2 500-2 690 MHz simplifying development and manufactu
45、re of equipment resulting in economy of scale and thus has added benefits for the developing countries; the propagation characteristics are more favourable than in the upper parts of the bands of 3-5 GHz. Furthermore, the plan for IMT deployment in this band is expected to be between years 2015-2020
46、. The exact timeline will depend on market needs and the various administrations requirements. At present, it is necessary to continue analysing the coexistence of ASR and meteorological radars with IMT systems. Please refer to the conclusion of the report for a more detailed description of where ad
47、ditional studies are needed. 2 Executive summary This contribution provides a compatibility analysis between air surveillance and meteorological radars and IMT systems operating within the 2 700-2 900 MHz band. The analysis is based on simulations that quantify interference levels between air survei
48、llance and meteorological radars and IMT base station to mobile links. This contribution also includes an operational analysis of several proposed interference mitigation techniques that is in part based on frequency dependent rejection analysis. 3 Scope This study provides a compatibility analysis
49、between air surveillance radars (ASR) and meteorological radars and IMT systems in the 2 700-2 900 MHz band. It describes technical matters related to the methodology, protection criteria, and mitigation techniques used to analyze potential compatibility. Details that describe the IMT and radar characteristics, ASR and meteorological radar interference criteria and IMT interference criteria used for the studies discussed in this text were taken from various ITU-R Recommendations and are summarized in Appendix 1 to Annex 1 Study A Compatibilit
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