Low complexity syndrome based decoding of Turbo codes

Reduced-Complexity Syndrome-Based TTCM Decoding

“…Similar to the bit-wise pre-correction sequence proposed in [5] for turbo codes, we make an estimate of the 2 n -ary symbol error in each iteration to ensure that the Hamming weight of the syndrome decreases with ongoing iterations. While the extrinsic information was used in [5] for the estimating the pre-correction sequence, we have improved the estimation by using the APP.…”

“…While the extrinsic information was used in [5] for the estimating the pre-correction sequence, we have improved the estimation by using the APP. This proceeds as follows:…”

“…More explicitly, the constituent TCM codes, which can be optimally designed using EXtrinsic Information Transfer (EXIT) charts [3], are concatenated in a parallel fashion and iterative decoding is invoked at the receiver for exchanging extrinsic information between the pair of TCM decoders. In order to reduce its decoding complexity, we propose to reduce the effective number of decoding iterations by appropriately adapting the syndromebased block decoding approach of [4], [5] for TTCM.…”

“…Therefore, the decoding complexity is substantially reduced at higher SNRs. This approach was then further extended to turbo codes in [5], where a pre-correction sequence 2 was also computed at each iteration to correct the errors. Thus, the decoding complexity was reduced not only at higher SNRs, but also for the higher-indexed iterations.…”

“…Against this background, our novel contribution is that we have extended the application of the syndrome-based MAP decoder of [10] together with the BSD of [5] This letter is organized as follows. In Section II, the block-based syndrome decoder designed for TTCM will be presented.…”