Satellite communication system using hierarchical modulation to transmit a plurality of modulated signals of high and low priority

摘要

A satellite communication system (10) using hierarchical modulation to transmit a plurality of modulated signals (12) to sub-regions (16) within a region (14). Each modulated signal includes high priority content and low priority content. The system (10) includes a satellite (20) equipped with a plurality of satellite transmitters (22) coupled to a plurality of antenna elements (24), e.g. a phased array of antenna elements (24). The antenna elements (24) are utilized selectively to direct a modulated signal from a satellite (20) transmitter to a distinct sub-region (16a). The satellite transmitters (22) and antenna also cooperate to broadcast the high-priority content to the region (14) such that a ground receiver (30) traveling from a first sub-region (16a) to an adjacent second sub-region (16b) adjacent will not experience a loss of high-priority content. First low-priority content of a first modulated signal (12a) directed to the first sub-region (16a) is independent of second low-priority content of a second modulated signal (12b) directed to the second sub-region (16b).