Channel capacity enhancement scheme for satellite communication system

In this paper, a hierarchical modulation scheme(and also known as embedded, multi-resolution, or asymmetrical constellation scheme) is studied for transmission of multimedia system. A hierarchical modulation scheme is presented to upgrade an existing digital broadcast system by adding more data stream in its transmissions. The hierarchical modulation is composed of a basic constellation, which is the same as in the original system, and a secondary constellation, which carries the additional data for the upgraded system. The upgraded system with the hierarchical modulation is backward compatible (BC mode) in the sense that receivers that have been deployed in the original system can continue receiving data in the basic constellation. Hierarchical receivers can be designed to receive data carried in the secondary constellation, as well as those in the basic constellation. Specifically, we propose general design guidelines for multimedia transmission over AWGN channels with an hierarchical Amplitude Phase Shift-Keying(APSK) constellation.