1、 Report ITU-R M.2172(12/2009)Radiolocation service sharing feasibility in the 154-156 MHz bandsM SeriesMobile, radiodetermination, amateurand related satellite servicesii Rep. ITU-R M.2172 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economic
2、al use of the radio-frequency spectrum by all 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 Wor
3、ld and Regional Radiocommunication Conferences 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 f
4、or the submission of patent statements and licensing 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
5、 of ITU-R Reports (Also available online at http:/www.itu.int/publ/R-REP/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, a
6、mateur and related satellite services 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 Note: This ITU-R R
7、eport was approved in English by the Study Group 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 written permission of ITU. Rep. ITU-R M.2172 1 REPORT
8、 ITU-R M.2172 Radiolocation service sharing feasibility in the 154-156 MHz bands (2009) Executive summary The report summarizes the sharing studies conducted in accordance with Resolution 611 (WRC-07) on WRC-12 Agenda item 1.14 which is to consider a primary allocation to the radiolocation service i
9、n the portion of the band 30-300 MHz for the implementation of new applications in the radiolocation service. The sharing studies presented in this Report were conducted in frequency band 154-156 MHz in order to assess sharing feasibility with fixed and mobile services. The results of sharing studie
10、s are summarized in the conclusion section of the Report. 1 Introduction Studies on protection criteria and technical characteristics of the radiolocation systems operating in VHF frequency range resulted in preparation of Recommendation ITU-R M.1802 Characteristics and protection criteria for radar
11、s operating in the radiolocation service in the frequency band 30-300 MHz. This Recommendation contains the typical characteristics of radars operating in the VHF band. Development of new applications in the radiolocation service closely related to significant growth of the number of space objects i
12、ncluding artificial debris. These applications are planned for used of aerospace surveillance and tracking the launch and manoeuvring of spacecrafts. They are based on design of effective and economical radars that can be implemented in the VHF range. WRC-12 Agenda item 1.14 was adopted at WRC-07 in
13、 order to address existing lack of spectrum available for radiolocation service in VHF band required for large-scale air and space surveillance operations. VHF radio waves propagate well through the ionosphere, thus enabling various space object detection applications including remote space sensing
14、and asteroid detection, as well as for defining the position of natural and artificial earth satellites, from terrestrial-based radiolocation systems. ITU-R studies based on the current requirements were limited to radiolocation systems for space-object detection from terrestrial locations in a port
15、ion of the band 30-300 MHz up to 2 MHz bandwidth systems, however allocation with a wider frequency range may provide flexibility and facilitate sharing with existing services. This report presents sharing studies between the radiolocation services systems and systems from other services in the band
16、 154-156 MHz. 2 Rep. ITU-R M.2172 2 Current use of the band 154-156 MHz and interference susceptibility of systems operating in the considered band The band 154-156 MHz is currently allocated worldwide to the fixed and mobile services on a primary basis. 2.1 Fixed, mobile, maritime mobile and aerona
17、utical mobile services susceptibility used in the study Recommendation ITU-R M.1808 provides technical and operational characteristics of conventional and trunked land mobile systems. Section 2.1 of Annex 1 of Recommendation ITU-R M.1808 states that “there are many methodologies used to ensure coexi
18、stence between conventional and trunked land mobile systems (e.g. field-strength contours, carrier-to-interference). For simplicity, an I/N of 6 dB could be used to determine the impact of interference. For applications with greater protection requirements, such as public protection and disaster rel
19、ief (PPDR), an I/N of 10 dB may be used to determine the impact of interference”. Reference1shows that in the 108-389 MHz frequency band, a permitted interference field strength is 12 dB(V/m) in 25 kHz for co-channel operation for 10% of time and 50% of locations. This value is commonly used in many
20、 Region 1 countries in bilateral and multilateral coordination in the land mobile service. Exceeding the above interference field strength reflects the need for coordination and for detailed studies on interference effect. Since it is applied at the border of potentially affected administrations and
21、 specifies the limitation for interference field strength it is not dependant on different mobile service receiver characteristics. 3 Characteristics of radiolocation service (RLS) used for the sharing studies 3.1 Spectrum requirement The spectrum requirement in the 30-300 MHz frequency range is cur
22、rently up to 2 MHz for radiolocation systems. The band 154-156 MHz was proposed in order to address this requirement. 1Recommendation CEPT T/R 25-08 Rev.2008 Planning criteria and coordination of frequencies in the land mobile service in the frequency range 29.7-921 MHz. Rep. ITU-R M.2172 3 3.2 Tran
23、smitter and receiver characteristics used for the sharing study TABLE 1 Radiolocation service (RLS) systems characteristics Radar (narrow-band radar) Radar (wideband radar) Frequency band (MHz) 154-156 Output pulse power (min/max) (dBW) 27/46 40/46 Mean output power (min/max) (dBW) 22/41 35/41 Polar
24、ization Linear Pulse duration (s) 13 000 3 200 Duty cycle 0.322 Modulation type pulse Altitude above the ground level (m) 19 Antenna type Phased array Maximum antenna gain (dB) transmitter receiver 25 30 Maximum antenna gain on the horizon (dB) 9 Antenna pattern See 1.1 in Appendix 1 Main beam patte
25、rn, degree horizontal plane (Rx/Tx) vertical plane (Rx/Tx) 2.6/5.2 2.6/2.6 Receiver noise temperature (K) 800 Operational receiver passband (kHz) (3 dB level) 0.132 625 Receiver thermal noise (dBW) 178.4 141.6 Characteristics of unwanted emission of radiolocation systems are given in 3 of Appendix 3
26、. 4 Sharing studies methodology 4.1 Impact from RLS into fixed, mobile and maritime mobile services systems For terrestrial (fixed, mobile and maritime mobile) radiocommunication stations, Recommendation ITU-R P.1546-4 methodology is used for calculation of propagation losses , and it is possible to
27、 determine limiting distances where this allowable field strength will be implemented. This distance will obviously be determined by propagation environment and transmitter e.i.r.p. Space navigation and tracking of the natural and man-made space objects does not require a large number of space surve
28、illance radars. It seems sufficient for any major space-exploring agency to operate 1-2 such radars, taking into account the opportunity to establish data exchange networks between such stations to update the orbital parameters of natural and man-made space assets. 4 Rep. ITU-R M.2172 Thus it is exp
29、ected that MS/FS stations may be susceptible to interference produced by no more than one space surveillance radar. Therefore, in sharing studies single radar is considered. 5 Results 5.1 Impact from RLS into fixed, mobile, maritime mobile and aeronautical (OR) mobile services systems 5.1.1 Results
30、of sharing studies in the frequency band 154-156 MHz The sharing studies between space surveillance radars and fixed/mobile stations in the 154-156 MHz frequency band were conducted using two approaches. The first approach to studies is based on protection criteria and technical characteristics of m
31、obile stations as specified in Recommendation ITU-R M.1808 and indicated in 2.1. Those studies have defined separation distances to enable acceptable interference levels to the mobile stations. The estimation results for narrow-band radars are shown in Table 2 and those for wideband radars are prese
32、nted in Table 3. The estimation of interference caused by a wideband signal assumed that only a portion of the electromagnetic energy emitted from the radar transmitter fell into the receiver passband. TABLE 2 Protection distances for the narrow-band signal I/N (dB) Eadd dB(V/m) Protection distance
33、(km) Land path Sea path Without polarization decoupling 6 11.9 650 710 10 15.9 695 760With polarization decoupling (polarization discrimination is assumed to be 16 dB) 6 11.9 470 520 10 15.9 520 570TABLE 3 Protection distances for the wideband signal I/N (dB) Eadd dB(V/m) Protection distance (km) La
34、nd path Sea path Without polarization decoupling 6 11.9 490 540 10 15.9 540 590With polarization decoupling (polarization discrimination is assumed to be 16 dB) 6 11.9 320 360 10 15.9 365 400Rep. ITU-R M.2172 5 The correction factor is defined as a ratio between the radar signal bandwidth and mobile
35、 service channel bandwidth. Technical characteristics from Table 1 and the channel bandwidth2of 25 kHz results in the correction factor of 14 dB to be equivalent to reducing the e.i.r.p. towards the horizon down to 41 dBW. The discussed estimations show that the protection distances for the wideband
36、 signal do not exceed 590 km assuming no polarization decoupling and 400 km assuming polarization decoupling. Narrow-band operation features significant increase in the protection distances, which could be up to 760 km assuming no polarization decoupling and up to 570 km assuming polarization decoup
37、ling. These results are based on assumed base station antenna heights of 60 m for fixed/ mobile systems; higher base station antenna heights would lead to greater separation distances. The obtained levels of protection distances would not signify infeasibility of sharing between the space surveillan
38、ce radars and the mobile stations. They only imply that the narrow-band operating radar would cause interference to mobile stations only in a co-channel scenario, and that the problem of their shared operation could be possibly addressed using interference mitigation techniques and frequency-distanc
39、e separation. The additional study provided in Appendix 2. This study is based on propagation model in Recommendation ITU-R P.1546 with 1% of time propagation mode. The study show that the required protection distances are as follows: for the narrow-band radar signal: I/N = 6 (dB): 892 km for analog
40、ue to 929 km for digital; I/N = 10 (dB): 939 km for analogue to 979 km for digital; for the wideband radar signal: I/N = 6 (dB): 706 km for digital to 721 km for analogue; I/N = 10 (dB): 748 km for digital to 763 km for analogue. The difference between protection distances obtained in this study wit
41、h respect to the results in other studies is because of the 1% of time propagation curves which were used in calculations. However, it should be noted that the application of 1% of time propagation curves was not agreed in ITU-R studies under WRC-12 Agenda item 1.14 and its application subject to ag
42、reement between administrations concerned. It also worth mentioning that the application, for example, of 50% of time propagation curves will result in much lower distances (around 300 km lower) required for protection of mobile services. In this study the scenario was considered when surrounding cl
43、utter is not obstructed and antenna height much higher than the height of surrounding clutter. The results mentioned in above studies correspond to worst case scenario and do not take into account statistical nature of interferences at FS/MS receiver front end. The mathematical model of antenna whic
44、h characteristics are presented in Table 1 was developed in order to estimate impact of statistical nature of interferences. In interference impact simulation it was taken into account that radar antenna scans in the vertical plane at angle from 2 to 70 and in the horizontal plane at angle from 0 to
45、 360. The simulation results are presented in Table 4. 2Assumption on channel bandwidth of 25 kHz for mobile service. The results may differ if the MS is operating with narrower bandwidth. 6 Rep. ITU-R M.2172 TABLE 4 The simulation results of statistical interference impact Antenna height of MS/FS s
46、ystems is 15 m I/N (dB) Narrow-band signal 6 Without cross-polarization With cross-polarization Separation distance (km) Separation distance (km) 460 290 Wideband signal Without cross-polarization With cross-polarization Separation distance (km) Separation distance (km) 310 170 The analysis of the r
47、esults shows that for the selected separation distances I/N = 6 dB is exceeded at not more than 20% of time. The increase of MS/FS station antenna height up to 65 m leads to increase of distances where I/N = 6 dB will be exceeded at not more than 20% of time. The simulation results of interference i
48、mpact for FS/MS station antenna height of 65 m are presented in Table 5. TABLE 5 The simulation results of statistical interference impact MS/FS system antenna height of 65 m I/N (dB) Narrow-band signal 6 Without cross-polarization With cross-polarization Separation distance (km) Separation distance
49、 (km) 510 330 Wideband signal Without cross-polarization With cross-polarization Separation distance (km) Separation distance (km) 350 205 The analysis of the obtained results shows that the separation distance, which provides protection criteria excess at the indicated percent of time with increase of receiving antenna height up to 65 m, increases not more than by 50 km. Analysis of Recommendation ITU-R F.758-4 shows that long-term protection criteria is used to provide protection of fixed service. The I/N = 6 dB which
