Factor graphs based iterative decoding of turbo codes

Turbo codes and low-density parity-check (LDPC) codes both have their advantages and can achieve the Shannon limited performance. Combining the turbo codes encoding and LDPC decoding, a new scheme based on factor graphs and sum-product algorithm is developed in this paper. It can reduce the decoding complexity of turbo codes greatly, and also has some guides in the designing of interleaver and the choosing of recursive systematic convolutional (RSC) constituent codes.