Algebraic Superposition of LDGM Codes for Cooperative Diversity
This paper presents a technique for achieving cooperative spatial diversity using serially concatenated Low Density Generator Matrix (LDGM) codes. Specifically, the authors consider a scenario in which a pair of transceivers employs algebraic superposition of error control codes to affect spatial diversity at their common destination. The construction of LDGM codes from a sparse generator matrix makes them a natural t for such a cooperative diversity scheme. The simple decoder structure for graph based codes reduces the complexity at the destination compared with previously-proposed schemes using algebraic superposition of convolutional codes and turbo-like decoding. The result is a system with low encoding and decoding complexity and improved error performance.