Improved Acceptance Criteria for Speculative Successive Cancellation Decoding of Polar Codes
2026-08-10 • Information Theory
Information Theory
AI summaryⓘ
The authors focus on improving how polar codes are decoded quickly and with low delay, which is important for fast data communication. They build on a method called speculative successive cancellation (Spec-SC) decoding, which tries two decoding paths at once and checks the result later to speed things up. Their new approach uses better rules to decide when to accept the speculative results, making it work faster especially for certain types of code segments. They also combine this with code membership testing to speed up more complicated cases. Their tests show these methods significantly reduce decoding time without making errors more likely.
polar codessuccessive cancellation decodingspeculative decodingHamming distanceellipsoidal distancecode membership testingdecoding latencyerror-rate performancefast simplified SC decoding
Authors
Marvin Rübenacke, Ryan Seah, Warren J. Gross
Abstract
Next-generation data-channel applications of polar codes demand decoding algorithms with high throughput and low latency. The recently proposed speculative successive cancellation (Spec-SC) decoding reduces average decoding latency by speculatively executing the right branch of successive cancellation (SC) decoding in parallel with the left branch, verifying the result once the g-function is computed. In this paper, we propose new acceptance criteria based on Hamming distance and ellipsoidal distance that improve acceptance rates, enabling greater speed-ups for lower-rate nodes. We further show that combining code membership testing with speculative decoding accelerates high-rate nodes as well. Numerical results confirm that both approaches outperform fast simplified SC (FSSC) decoding and Spec-SC with the original acceptance condition in terms latency by a wide margin, with virtually identical error-rate performance.