Advanced Satellite Broadcasting System

Toward the realization of a 21 GHz-band satellite broadcasting system

Toshihiro NOMOTO, Senior Research Engineer,
Digital Satellite Broadcasting Systems

Radio waves are more affected by rain attenuation at higher frequencies. The current satellite broadcasting system utilizes the 12 GHz-band, and a future 21 GHz-band broadcasting system is under examination. In such high frequency satellite broadcasting, techniques to overcome signal attenuation due to rain will be of increasing importance. For this reason, we are conducting research on the following techniques:

Variable beam pattern satellite system Heavy rainfall tends to occur in only a limited area at any one time. This satellite system uses a large scale phased array antenna to concentrate the emission beam on the area of heavy rainfall and compensate for rain attenuation. (Figure 1)

Figure 1: Variable beam pattern satellite system

Super-long-period interleave scheme This technique is under consideration for use with recorded programs. In this scheme, the transmitting signals are interleaved for a long time span such as 24 hours. The receiver accumulates the interleaved data and properly decodes (de-interleaves) the data. A partially damaged signal due to rain attenuation can be recovered, or restored to a complete signal by error correction after de-interleaving. (Figure 2)

Figure 2: Super-long-period interleave transmission