Apparatus and method for support of communications services and applications over relatively low signal-to-noise ratio links

摘要

A physical layer PL frame generation method is provided. A PL payload (313, 333) is generated by encoding and modulating source data based on a first modcod of a first set. A synchronization header (315) (a unique word UW of a UW set) is appended to the PL payload. The UWs of the set respectively correspond to different modcods of the first set, and the UW corresponds to the first modcod. A PL header (215) is appended to the synchronization header and PL payload to form the PL frame. The PL header comprises a second UW (221) and physical layer signaling PLS data (223). The PLS comprises encoded data fields reflecting a length of the PL frame, where the data fields are encoded based on a second modcod scheme of a second set. The first modcod set is designed for an SNR operating range relatively lower than the SNR operating range of the second modcod set.