1、 Rec. ITU-R F.1489 1 RECOMMENDATION ITU-R F.1489*, *A METHODOLOGY FOR ASSESSING THE LEVEL OF OPERATIONAL COMPATIBILITY BETWEEN FIXED WIRELESS ACCESS AND RADIOLOCATION SYSTEMS WHEN SHARING THE BAND 3.4-3.7 GHz (Questions ITU-R 140/9 and ITU-R 215/8) (2000) Rec. ITU-R F.1489 The ITU Radiocommunication
2、 Assembly, considering a) that the frequency band 3 400-3 700 MHz is allocated on a primary basis to the fixed service (FS) and the fixed-satellite service (FSS), amongst other services; b) that this band, amongst others, is used for terrestrial systems operating in the FS for providing fixed wirele
3、ss access (FWA) in a variety of situations, and that this use is growing rapidly in many countries, in particular developing countries; c) that the characteristics of FWA and radiolocation systems can make compatibility difficult to achieve, noting a) that there is interest in harmonizing the use of
4、 FWA systems in this band; b) that, according to RR. No. S5.433, the radiolocation service is also allocated on a primary basis in Regions 2 and 3 and on a secondary basis in Region 1 in the band 3 400-3 700 MHz; c) that generally FWA applications use multipoint architectures, comprising a multiplic
5、ity of base and user terminals over an area; d) that there is a need to protect co-primary services and to assess further the sharing conditions between FWA systems and these services; e) that Recommendation ITU-R M.1461 provides calculation procedures which may be used when performing sharing studi
6、es between FWA and radiolocation systems, recommends 1 that when performing frequency sharing studies between FWA and radiolocation systems, the methodology contained in Annex 1 should be considered; 2 that the information gathered from studies performed using this methodology may be applied to dete
7、rmine whether or not intended FWA operations are sufficiently distant from routine or frequent operating areas of radiolocation systems, so as to not receive interference, and/or to determine suitable mitigation techniques that could be implemented (see Note 1); 3 that administrations should make th
8、e relevant studies, including those that used other methodologies, available to the appropriate Radiocommunication Study Groups whenever possible; 4 that sharing criteria needed to ensure compatible operation between FWA and radiolocation systems should be developed, taking into account available mi
9、tigation techniques and the results of assessment methodologies, such as in Annex 1. NOTE 1 Mitigation options for ensuring the compatibility between digital radio-relay systems and radar systems are given in Recommendation ITU-R F.1097. _ *This Recommendation was jointly developed by experts of Rad
10、iocommunication Study Groups 8 and 9, and future revisions should be undertaken jointly. *This Recommendation should be brought to the attention of Radiocommunication Study Groups 4 and 8. 2 Rec. ITU-R F.1489 ANNEX 1 Methodologies for assessing the level of compatibility between FWA and radiolocatio
11、n systems 1 Introduction The use of FWA systems to improve teledensity and variety of services throughout the world has increased and continues to gain acceptance in a variety of situations, including developing countries. To determine compatibility between FWA and radiolocation systems in a specifi
12、c band, sharing studies should be conducted and where practical, actual measurements should be made. This Annex outlines the steps for performing these sharing studies. The results of studies performed in this manner should be carefully analysed to determine if the particular sharing scenario is fea
13、sible for any combination of FWA system and appropriate radiolocation systems operating in the same band. 2 Methodology The study should be performed in accordance with the following: a) Characterize those FWA system parameters that are considered to be critical to ensuring compatibility, and define
14、 acceptable performance in terms of threshold of acceptable service degradation. This involves the following receiver and other system characteristics. It should be noted that in all cases both base stations and user terminals should be considered: sensitivity, receiver noise floor, selectivity, err
15、or detection and correction of corrupted/missing data bits (techniques and parameter values such as bit-error ratio (BER), co- and adjacent-channel/s interference rejection, spurious responses, recovery time, automatic gain control (AGC)/limiter response time, receiver saturation level, non-recovera
16、ble degradation, receiver intermodulation, modulation scheme/s, bandwidths and data rates with associated bit or byte error rate requirements, antenna gain patterns or side-lobe levels, typical antenna heights and base-station siting (hilltop, low point, etc.). b) Establish the radiolocation system
17、characteristics (transmit power, pulse duration and duty cycle etc., using, for example, Recommendation ITU-R M.1465 Characteristics of, and protection criteria for, radars operating in the radiodetermination service in the frequency band 3 100-3 700 MHz). For solid-state radar transmitters it shoul
18、d be noted that transmitter pulse lengths and duty cycles are expected to be of the order of 1 ms and 25% respectively in the foreseeable future. c) Analyse the effects of radiolocation systems on FWA installations. For the anticipated range of radiolocation emission parameters, determine the tolera
19、ble I/N or C/I ratios by analysis (see Notes 1 and 2). Deterministic or probabilistic (closed-form) modelling techniques might be suitable with respect to some degradation forms, but simulation or Monte Carlo techniques should be used when necessary for other degradation measures. Rec. ITU-R F.1489
20、3 d) Using the resulting I/N and/or C/I criteria, assess the impact of radar emissions on FWA systems by means of interference-level/coupling computations in accordance with Recommendation ITU-R M.1461 Procedures for determining the potential for interference between radars operating in the radiodet
21、ermination service and systems in other services. e) Verify that FWA equipment available for test is operating within its specifications as determined in a), with particular attention directed to the following items: selectivity; frequency response; noise figure or receiver noise temperature; dynami
22、c range (saturation level); spurious responses; recovery time; BER with only desired signals present; cross-modulation; intermodulation. f) Characterize the performance degradations of the FWA receiver system from various undesired signal sources by means of bench testing. The undesired sources shou
23、ld be coupled into the FWA system along with the desired signal(s). A full range of undesired signal parameters should be used, including various pulse widths and pulse-repetition rates. The desired and undesired signal levels will be varied and measures of performance (as defined in a) will be meas
24、ured and recorded. The results may be presented in terms of signal-to-interference, S/I, ratio, and should be compared to those obtained from the analysis in c). g) Characterize the antenna frequency response and radiation pattern in a frequency range determined as necessary from the above analyses,
25、 which should include at minimum the range 3 400 to 3 700 MHz band. h) Calculate the effects of radiolocation emissions on FWA system deployments. Develop the findings in the form of frequency-distance separation curves. i) Install, where necessary, a representative FWA system adjacent to identified
26、 radiolocation systems and measure interference effects of radiolocation emitters to FWA receivers through field testing. The data obtained from the measurements should be used to validate the radiolocation system to FWA system analysis results. j) Determine those FWA system parameters, including tr
27、ansmitter power, antenna gains, side-lobe levels, antenna heights, and siting practice, that are critical to ensuring compatibility. k) Calculate the aggregated impact of representative, complete FWA system deployments on radiolocation systems, using the radar (I + N)/N criterion and interference-le
28、vel/coupling computations as described in Recommenda-tion ITU-R M.1461. The specific multiple-access technique, with a realistic multiplicity of users, may need to be reflected in the models and/or simulations. l) Evaluate the possible variations in likely FWA system deployments and their illuminati
29、on by radiolocation systems, and vice versa, with a view to undertaking possible additional measurements and/or calculations on the aggregated effects. m) If appropriate, summarize the final results in the form of frequency-distance separation curves and/or any other appropriate forms. NOTE 1 Examples of tolerable I/N for unwanted emissions from radar systems are given in Recommenda-tion ITU-R F.1190. NOTE 2 General guidance for sharing criteria for the FS is given in Recommendation ITU-R F.758.
