New Combinatorial Construction Techniques for Low-Density Parity-Check   Codes and Systematic Repeat-Accumulate Codes
  This paper presents several new construction techniques for low-density parity-check (LDPC) and systematic repeat-accumulate (RA) codes. Based on specific classes of combinatorial designs, the improved code design focuses on high-rate structured codes with constant column weights 3 and higher. The proposed codes are efficiently encodable and exhibit good structural properties. Experimental results on decoding performance with the sum-product algorithm show that the novel codes offer substantial practical application potential, for instance, in high-speed applications in magnetic recording and optical communications channels. 
Alexander Gruner and Michael Huber
cs.IT cs.DM math.CO math.IT