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arXiv · 2608.02760

Speculative Successive Cancellation Decoding of Polar Codes

Ryan Seah·Marvin Rübenacke·Warren J. Gross
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Abstract

Polar codes achieve channel capacity as block length increases, but this asymptotic advantage comes at the cost of decoding speed: the conventional successive cancellation (SC) algorithm is inherently sequential, which limits its practicality for high-throughput applications. This work addresses that limitation by introducing the \emph{Speculative Successive-Cancellation} (Spec-SC) framework, which incorporates speculative execution into the SC decoding process. While node-based decoders with special nodes enable partial parallelism for specific, predefined structures, Spec-SC extends this capability by permitting parallel execution in general nodes that do not match any special-node pattern. A built-in verification mechanism ensures that this speculation does not compromise decoding correctness. Simulation results show that Spec-SC achieves identical BER and FER performance to standard SC decoding, while reducing the average number of sequentially traversed nodes by up to $69\%$ for a polar code of length $N=4096$. These results demonstrate that Spec-SC enables additional algorithm-level parallelism beyond what special-node approaches alone can achieve, paving the way for speculative hardware decoder implementations.

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Ryan Seah, Marvin Rübenacke, Warren J. Gross. 2026-08-03. Speculative Successive Cancellation Decoding of Polar Codes. https://arxiv.org/abs/2608.02760

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