A Low-Complexity Serial List Viterbi Decoder of CRC-Aided TBCC for Broadcasting Services in 6G

In 6G broadcasting, there is an urgent need of a high-performance short-length channel code for hyper-reliable and low-latency communications (HRLLC). Among the available options, cyclic redundancy check-aided tail-biting convolutional code (CRC-TBCC) is recognized as a competitive candidate. To further enhance the competitiveness of CRC-TBCCs, this paper aims to design low-complexity serial list Viterbi decoders (SLVDs) for them. In the proposed decoder, we first apply regular sectionalization on the original trellis to obtain the sectionalized trellis (ST) and then remove all edges whose log-likelihood ratios (LLRs) are below a given threshold to obtain the edge-reduced ST (E-ST). The resulting decoder is termed E-ST-SLVD. We show that there exists an efficient method to determine the desired threshold for ST. We then analyze the decoding complexity the proposed decoder and the interrelationships among key parameters influencing decoding complexity. We finally present extensive numerical results to show that, with appropriate sectionalization length and threshold, the E-ST-SLVD admits a lower complexity than the original SLVD. Meanwhile, we have compared the decoding complexities of several competitive short-length codes for broadcasting to show the advantage of the proposed decoder. These result makes CRC-TBCC an attractive candidate for integrated broadcasting and mobile services in 6G.