Multiple rate low-density parity-check codes with constant blocklength

This paper presents a new method to design low-density parity-check codes for a variety of different rates that all share the same fundamental decoder architecture. Combining rows of the parity-check matrix for the lowest rate code produces the parity-check matrices for higher rates. An important advantage of this approach is that all effective code rates have the same blocklength. These LDPC codes also share the same variable degree distribution. The proposed design method maintains good graphical properties and hence low error floors for all rates. Furthermore, an imposed matrix structure facilitates a low complexity encoding and decoding of the codes.