Recommendation ITU-R F.758 [22] provides fixed service charactersitics for sharing with aircraft-mounted FSS Earth stations in the 27.5-29.5 GHz band.. As specified in the Recommendation (Annex 2, Section 4), the system parameters providedare not representative of any actual FS system, but represent an averaging or an expected range of values suitable for generic sharing/compatibility studies.
Stations FS5 and FS6 in the Table 70 Error! Reference source not found.below have parameters in line with the Rec. ITU-R F.758 [22]. . FS1 and FS3 stations are representative of typically deployed PP FS stations. FS2 is representative of a longer than typical link operating mountainous terrain and hence an elevation angle of 5 degrees is appropriate[A1] , . FS4 is representative of a P-MP Hub station. P-MP subscriber stations are expected to have parameters similar to those valid for PP stations.
Antenna radiation patterns for FS-PP are usually assumed in sharing studies using the formulas in Recommendation ITU-R F.699 [23] (when a single FS system is considered as victim/interferer) or Recommendation ITU-R F.1245 [24] (when averaging among a number of FS systems as victim/interferer). For P-MP it is recommended to use Recommendation ITU-R F.1336 [25].
[A1]But no justificiation for FS3 which has a higher elevation angle of 10 degrees?
Table 70: Recommended FS characteristics for FS vs FSS studies
Parameter | FS1 (PP) | FS2 (PP) | FS3 | FS4 | FS5 (PP based on Rec. ITU-R 758-5) | FS6 (P-MP based on Rec. ITU-R 758-5) | Notes |
RX antenna height | 20 m | 20m | 20m | 20m | Not specified, 20m is suggested | Not specified, 20m is suggested | |
RX antenna pattern | ITU-R | ITU-R | ITU-R | ITU-R | ITU-R Rec. | ITU-R | Source: |
Receiver noise figure, F | 6 dB | 6 dB | 6 dB | 6 dB | 8 dB | 8 dB | See note (1)[1] |
RX frequency | 28 GHz | 28 GHz | 28 GHz | 28 GHz | 24.25 – 29.50 GHz | 24.25 – 29.50 GHz | |
RX elevation angle | 0° | 5° | 10° | 0° | Not specified, 10° is suggested | Not specified, 0° is suggested | |
RX peak gain | 45 dBi | 43 dBi | 35 dBi | 18 dBi | 6.5 dBi | See note (2)[2] |
The Spectrum Mask for P-P and P-MP can be found in ETSI EN 302 217-2-2 [26] Annex A (table A4) and EN 302 326-2 (Section 5.3.4.1) respectively. Blocking information is available from EN 301 390 (Section 7).
With respect to antenna height for P-P, the BS and TS minimum antenna height are 20 m and for P-MP, the BS minimum antenna height is 20 m and the TS minimum antenna height is 1.5 m.
For the antenna elevation, some countries have reported an elevation range of 3 to 10 degrees. In rare cases a range of maximum elevation angle from 15 to 30 degrees has been reported.
ECC Report 100 uses an I/N ≤ -10 dB; I/N ≤ -6 dB is mentioned only for the protection of ENG/OB. FS systems (P-P and P-MP) commonly adopt I/N ≤ -10 dB in line with Rec. ITU-R F.758 [22]
[1] The System noise power density shall be obtained from the following equation:
N0 (dBW/Hz)= F(dB) + 10*log10(kT0)
where : T0 = 290 K, F is the noise figure and k is the Boltzmann constant. This is equivalent to:
N0 (dBW/Hz) = F(dB) - 204 (dBW/Hz) or N0(dBm/MHz) = F(dB) - 114 (dBm/MHz)
[2] The difference between the peak gain values of stations FS1 and FS2 comes from the fact that a typical PP FS station with high elevation angle (10°) is usually employed for short-range links near hilly areas.