System for time division multiplexing broadcast channels with R-1/2 or R-3/4 convolutional coding for satellite transmission via on-board baseband processing payload or transparent payload

A method of formatting broadcast channels for transmission via satellite to remote receivers in a satellite direct broadcast system comprising the steps of:

• framing said broadcast channels into broadcast channel frames;
• coding said broadcast channel frames using Reed-Solomon coding;
• interleaving said broadcast channel frames;
• and
• selecting one of a first convolutional encoder and a second convolutional encoder, said first convolutional encoder and said second convolutional encoder each being operable to receive broadcast channel frames comprising n×L bits per frame where n is an integer number and L corresponds to a predetermined number of input bits from said broadcast channels, and to generate a first number of output bits and a second number of output bits, respectively, said output bits generated by said first convolutional encoder being transmitted to said remote receivers at a first bit rate that is higher than a second bit rate corresponding to said output bits generated by said second convolutional encoder;
• wherein L is approximately 7136 bits and said coding step comprises the step of using a Reed-Solomon (223, 255) coder, said broadcast channel frames each comprising approximately n×7136×(255/223) or n×8160 bits;
• wherein said first convolutional encoder and said second convolutional encoder corresponds to a R-½ convolutional encoder and a R-¾ convolutional encoder, respectively, and said broadcast channel frames each comprise approximately n×8160/0.5 or n×16320 bits and approximately 8160/0.75 or n×10880 bits;
• wherein said framing step comprises the step of generating said broadcast channel frames having an approximately 0.432 second period at a broadcast station, and further comprising the step of generating time division multiplexed frames having an approximately 0.138 second period using said broadcast channel frames;
• and
• wherein said broadcast channel frames correspond to 0.432 second prime rate channels comprising two-bit symbols and said generating step for generating time division multiplexed frames further comprises the steps of:
• aligning said two-bit symbols in a plurality of said prime rate channels to a time division multiplexed frame symbol clock;
• arranging said plurality of said prime rate channels in parallel;
• and
• writing said two-bit symbols to at least one of said time division multiplexed frames in groups, corresponding ones of said two-bit symbols in said parallel prime rate channels being arranged serially in said groups, each of said groups comprising a number of said symbols corresponding in number to said parallel prime rate channels.