A generalization of the fast successive cancellation decoding algorithm to the case of binary polar codes with arbitrary large kernels is presented. Its asymptotic latency is shown to be
O(N1−1/μ), where$\mu $is the scaling exponent of the underlying polarization kernel.
Non-binary polar codes (NBPCs) decoded by successive cancellation (SC) algorithm have remarkable bit-error-rate performance compared to the binary polar codes (BPCs). Due to the serial nature, SC decoding suffers from large latency. The latency issue in BPCs has been the topic of extensive research and it has been notably resolved by the introduction of fast SC-based decoders. However, the vast majority of research on NBPCs is devoted to issues concerning design and efficient implementation. In this paper, we propose fast SC decoding for NBPCs constructed based on 2 x 2 kernels. In particular, we identify various non-binary special nodes in the SC decoding tree of NBPCs and propose their fast decoding. This way, we avoid traversing the full decoding tree and significantly reduce the decoding delay compared to symbol-by-symbol SC decoding. We also propose a simplified NBPC structure that facilitates the procedure of non-binary fast SC decoding. Using our proposed fast non-binary decoder, we observed an improvement of up to 95% in latency concerning the original SC decoding. This is while our proposed fast SC decoder for NBPCs incurs no error-rate loss.
A method for efficiently successive cancellation (SC) decoding of polar codes with high-dimensional linear binary kernels (HDLBK) is presented and analyzed. We devise a
l-expressions method which can obtain simplified recursive formulas of SC decoder in likelihood ratio form for arbitrary linear binary kernels to reduce the complexity of corresponding SC decoder. By considering the bit-channel transition probabilities
WG(⋅)(⋅∣0) and
WG(⋅)(⋅∣1) separately, a
W-expressions method is proposed to further reduce the complexity of HDLBK based SC decoder. For a
m×m binary kernel, the complexity of straightforward SC decoder is
O(2mNlogN). With
W-expressions, we reduce the complexity of straightforward SC decoder to
O(m2NlogN) when
m≤16. Simulation results show that
16×16 kernel polar codes offer significant advantages in terms of error performances compared with
2×2 kernel polar codes under SC and list SC decoders.