1、ERC REPORT 19 VY Euroean Radiocommunications Committee (ERC ., -_.- -. 9. within the European Conference of Postai and Telecommunications Administrations (CEPT) SHARING BETWEEN EARTH EXPLORATION SATELLITE SERVICES (PASSIVE) AND FIXED SERVICES IN THE BAND 54.25 - 57.2 GHz Montreux, October 1993 Copyr
2、ight 1994 the European Conference of Postai and Telecommunications Administrations (CEPT) ERC REPORT 19 Page 1 Output power I 1odBw Antenna gain in zenith direction I standard antenna: 3 dBi SHARING BETWEEN EARTH EXPLORATION SATELLITE SERVICES (PASSIVE) AND FIXED SERVICES IN THE BAND 54.25 - 57.2 GH
3、z I 1. INTRODUCTION The SE group has identified a need for compatibility studies between the Earth Exploration-Satellite (passive) and Fixed services (EESS and FS) allocated in the Radio Regulations in the frequency band 54.25 - 58.2 GHz. Within ETSI, standards for the fixed service are being develo
4、ped for the subbands 54.25 - 57.2 GHz and 57.2 - 58.2 GI G(4) = 45 dBi, 0.122 4 0.303; G(4) = 32 - 251og 0 Bi, 0.303 0 48“; G(4) = -10 dBi, 48 4 180“. For the reference case, a discrimination of 29.1 dB is required at the sensor antenna, in order to avoid harmful interference. This is obtained for a
5、n off-axis angle of 4 = 0.698“. This means that a FS station operating Within a circle with a radius of about 6.1 km (500 . tan 0.698“ = 6.09) below the sensor will cause an interfering signai in excess of the threshold. Thus, the coverage area lost due to one FS station is a circle with the maximum
6、 radius 6.1 km. This radius becomes smaller as the frequency is increased (see Figure i). A coordination procedure is necessary to avoid that essential coverage areas are lost for the passive sensors. The coverage loss can be reduced by - use of high performance FS antennas andlor - reduction of the
7、 output power of the FS station. STD.CEPT ERC REPORT 19-ENGL 1793 I 2326414 0015148 377 m ERC REPORT 19 Page 3 6. COORDINATION-FREE DEPLOYMENT For coordination-free deployment of FS stations, it is necessary to ensure that all FS stations have a sufficient margin, so that the interference threshold
8、is never exceeded at the sensor. An equation can be derived to calculate the margin that must be upheld by the FS stations: mg= 101og6- 1 dB 6 = density of FS stations (stations/km2/250 MHz) Note : The margin must always be greater than O. 6.1 Example If the expected density of FS stations is 25 the
9、n is 13 dB. The margin for a station at 55 GHz with 0 dBW ouput power and standard antenna is -16 dB according to Figure 1. This margin must then be improved by 29 dB. This can be achieved in two ways: - by using a high performance antenna and the output power -16 dBW, - by using a standard antenna
10、and the output power -29 dBW. Note 1: The value d = 25 has been arbitrarily chosen to demonstrate the procedure. Note 2: In practice, an output power of O dBW cannot be achieved with the technology currently available. A more realistic value is somewhere between -10 and -20 dBW. 7. CONCLUSIONS The a
11、nalysis shows that EESS (passive) will receive interference from FS stations, resulting in a loss of coverage area for the passive sensors. The interference levels are higher in the lower part of the band 54.25 - 57.2 GHZ, due to the effects of the oxygen absorption. The result of the study clearly
12、indicates that there is a need for coordination between FS and EESS, when FS parameters according to the ETS are used. Administrations should ensure that effective frequency coordination procedures are set up to enable the two services to Co-exist. A reduction in the output power of FS stations woul
13、d make coordination-free deployment of FS stations possible. The size of the necessary reduction is dependant upon the frequency and the type of antenna used. ERC REPORT 19 Page 4 Figure 1. Margin vs. frequency; O dBW output power, standard antenna. .5 I- l I l I I I #+ I l I I l I I Frequency (GHz)
