Patent ID: 7581159

Claim:
An apparatus for transmitting encoded signals, comprising: a memory resource, for storing data corresponding to selected locations of bit positions of a code word to be shortened and punctured, the selected bit positions determined, for a desired code word length of a set of available code word lengths for a low-density parity-check code, and for a desired code rate, by: selecting a starting code word length corresponding to the desired code word length, the starting code word length corresponding to a subset of the set of available code word lengths; determining a number of shorten bits to be shortened from an information portion of the starting code word length, and a number of puncture bits to be punctured from the starting code word length, responsive to the desired code rate and to a difference in code word length between the desired code word length and the starting code word length; selecting shortened code word bit positions of the starting code word and punctured code word bit positions of the starting code word, to produce a code word having the desired code word length and a number of information bits and a number of parity bits corresponding to the desired code rate; circuitry, coupled to the memory resource, for encoding code words at the starting code word length, according to the low-density parity-check code, and for puncturing and shortening the encoded code words at the selected bit positions to obtain length-reduced code words of the desired code word length and at the desired code rate; a modulator, for modulating signals corresponding to the length-reduced code words; digital-to-analog converter circuitry, for generating an analog signal corresponding to the modulated signals; and transmitter circuitry, for transmitting the analog signal over a communications facility.