Multipoint TDM data distribution system

摘要

A TDM data distribution system (10) includes a hub unit (12) with a multipoint transmitter (24) and any number of subscriber units (14), each of which has a multipoint receiver (28). A forward communication link (16) transmitted by the hub unit (12) exhibits a substantially constant baud and carrier frequency over a number of diverse modulation format (MF) time slots (42). However, the different MF slots (42) convey data using different modulation formats. Modulation order and coding rate may vary for different modulation formats. The multipoint transmitter (24) includes a number of encoding FEC processors (48), wherein each encoding FEC processor (48) is active only for selected ones of the different MF slots (42). When inactive, the internal states of the encoding FEC processors (48) are frozen. Each multipoint receiver (28) includes a decoding FEC processor (108) which is active only for MF slots (42) assigned to the same modulation format for which the decoding FEC processors (108) are programmed. When inactive, the internal states of the decoding FEC processors (108) are frozen.