Improvement of K‐band satellite link transmission capacity and availability by the transmitting power control

Abstract

AbstractTo cope with the rain attenuation in K‐band (quasi‐millimeter waveband) satellite communication, the effect of a transmitting power control scheme which controls adaptively the onboard transponder transmitting power toward each earth station according to the downlink rain attenuation, is clarified quantitatively. Also, the design of the FDMA satellite communication system with transmitting power control is made possible. Probability distribution of the downlink rain attenuation is used to represent each FDMA carrier transmitting power. the total transmitting power of the transponder is obtained as the sum of these FDMA carrier powers by using the central limit theorem. By the probability density function of this total power and the upper limit of this total power which is determined by the transponder maximum transmitting power and the output backoff, the maximum allocatable FDMA channels per transponder is derived. Further, the channel capacity of the overall system is calculated, taking account of rain attenuation distribution, regional differences of satellite antenna gain, and regional distribution of earth stations. By these procedures, the allocatable number of channels and the link availability are derived, and the design of the FDMA satellite communication systems with transmitting power control is made possible. As an example, considering Japanese CS‐2 satellite, the number of channels and link availability for 64 Kbps and 1.544 Mbps earth stations with antenna diameter 3 mø, are shown.