Enhanced Successive Cancellation List Decoder for Long Polar Codes Targeting 6G Air Interface

The 6th generation communication standard's air interface requires innovation in channel coding to fulfill anticipated energy and area cost reduction requirements. In this paper, we propose algorithmic techniques to enable the implementation of long polar codes (e.g., length 8K bits) in next-generation communications standards by addressing key challenges in memory usage and computational complexity presented by successive decoding list (SCL) polar decoding. Perturbation-enhanced (PE) successive cancelation list (SCL) decoders with a list size of $L$ reach the decoding performance of the SCL decoder with a list size of $2L$. The proposed bias-enhanced (BE) SCL decoders, which simplifies the PE SCL decoder based on insights gained by an ablation study, returns similar decoding performance to PE SCL decoders. Also, proposed BE generalized partitioned SCL (GPSCL) decoders with a list size of $8$ have a $67\%$ reduction in the memory usage and similar decoding performance compared to SCL decoders with a list size of $16$. Furthermore, input-distribution-aware (IDA) decoding is applied to BE GPSCL decoders. Up to $5.4\times$ reduction in the computational complexity is achieved compared to SCL decoders with a list size of $16$. The degraded decoding performance is at most $0.05\text{ dB}$ compared to BE GPSCL decoders without IDA decoding.