The application provides a
polar code soft input soft output decoding method, a decoding device and a
communication device; the decoding method comprises the following steps: (S1) performing fast serial cancellation
list decoding under dynamic frozen bit constraint for all special nodes constituting a
polar code; the types of the special nodes comprise rate zero, rate one, repetition and
single parity check; (S2) calculating the approximation of the sum of the posterior probabilities of the legal code words not accessed under each special node after decoding; (S3) using the approximation of the
code book probability obtained in the step (S2) to calculate the bit level
soft information of the output
polar code. The low-latency polar code soft input soft output decoding method provided by the application improves the parallelism by realizing fast soft output decoding based on the Rate0, Rate1, REP and SPC nodes, and significantly reduces the
decoding latency without losing the soft output precision compared with the SO-SCL decoding
algorithm.