Successive Cancellation (SC) Decoding for Polar Codes

This implementation demonstrates the SC (Successive Cancellation) decoding algorithm for Polar codes, providing a comparative reference against the original BP (belief propagation) based "Polar code encoder and decoder." The SC decoding process involves sequentially decoding received codewords through a recursive cancellation mechanism that corrects error bits progressively. The algorithm typically implements a tree structure traversal using log-likelihood ratio (LLR) calculations, where each decoding stage eliminates one potential error source through hard decision functions. In contrast, the BP decoder employs probability propagation algorithms that perform iterative message passing between check and variable nodes, utilizing Tanner graph representations and sum-product operations to enhance decoding accuracy. Both methodologies present distinct advantages: SC decoding offers lower computational complexity with sequential bit processing, while BP decoding provides superior performance through parallel iterative refinements. The selection between these approaches depends on specific application requirements including latency tolerance, error correction performance thresholds, and computational resource constraints.