Complexity reduced turbo decoding with concatenated detection codes

In this paper, we present a complexity reduced turbo decoding method by using concatenated error detection codes with the turbo codes. First, a large data frame for turbo encoding is divided into multiple small packets followed by cyclic redundancy check (CRC) parity bits. The essential idea is to fully utilize the interim CRC detection results inside the turbo decoding. Trellis constraints are exploited to redesign the turbo decoding algorithms so that a large reduction in computational complexity, as well as an excellent decoding performance, can be achieved. Experimental results over the constrained log-MAP algorithm is provided. However, the idea proposed in the research is generic to any trellis-related decoding algorithms when the decoder has the knowledge that some of bits have been correctly decoded. Furthermore, the error localization feature provided by this method is also important to applications such as source data post-processing and hybrid-ARQ.