Quantitative evaluation of adaptive satellite power control using Japanese rain radar data

In order to realize future large-capacity, high-speed and highly advanced multimedia satellite communication and broadcasting systems, utilization of Ka-, Q-, V- and even W-bands radio wave is indispensable. In such radio link, performance degradation due to rain-induced attenuation and noise increase, gaseous attenuation, rain- or ice-induced depolarization and interference from other systems is expected. Above all, rain attenuation is the most significant factor for link performance. This is the reason that attenuation mitigation becomes very important. To cope with such large attenuation events, powerful attenuation mitigation technologies should be developed. Attenuation mitigation methods are roughly classified into the following three categories as shown in Table 1; Static methods such as margin increase in transmitter and receiver system. These are not suitable in the system in which large attenuation is expected. Adaptive methods such as adaptive EIRP allocation toward the area suffered from large attenuation. They are effective in large attenuation case within a limit of total resource capability such as satellite total power. Diversity methods such as site- and time-diversity. They prepare several redundant links which have low attenuation correlation and adopt the best performance link selectively. In this paper, the authors assume adaptive satellite power control method by which satellite transmitting power for relevant area is increased using multi-beams or modified beam pattern. The effect of this method is evaluated by using rain-radar data obtained in Japan. Especially, link performance within a beam is evaluated.