A study on uplink (30 GHz) rain attenuation characteristics and up- and downlink available time percentages in Ka-band satellite communication

Abstract

SUMMARYUsing the CS-2 and CS-3 beacon levels (19.45 GHz) observed for the past 6 years, this paper discusses the time percentages of up-and downlink attenuation when the signal is transmitted from the Osaka Neyagawa to Tokyo Setagaya station via satellite. The uplink attenuation in the 30-GHz band is inferred in a more realistic manner by selecting a relevant kind of raindrop size distribution (DSD) for each rainfall event from three representative types, namely, Jd (drizzle), MP (standard), and Jt (thunderstorm), based on cross-polar phase measurement at each event. The resulting time percentages of the uplink attenuation tend to decrease by about 0.005% for attenuation larger than 20 dB (time percentages < 0.05%) due to possible effects of the Jt-type DSD, compared with those inferred by the MP-type DSD only. This tendency is also found in up-and downlink attenuation of nearly 30 dB. The time percentages of bidirectional up-and downlink attenuation between the Neyagawa and Setagaya stations show a characteristic difference of about 50%, depending on the transmission directions each year, but they have nearly the same long-term statistics over the 6 years. Also, the time percentages of up-and downlink attenuation of between 4 and 5 dB increase by about 0.1% due to the probability of simultaneous occurrence of the attenuation between the two stations, compared with those inferred with this simultaneous occurrence neglected.