Successive-Cancellation Flip Decoding of Polar Codes Under Fixed Channel-Production Rate

TL;DR

This paper introduces a multi-threshold SCF decoding mechanism for polar codes that maintains fixed data rates and prevents buffer overflow, improving error correction with minimal complexity increase.

Contribution

It proposes a novel multi-threshold mechanism for SCF decoding that ensures fixed-rate operation and reduces buffer overflow risk in polar code decoders.

Findings

Better error correction than codeword dropping

Prevents buffer overflow at 1.125 times lower rate

Operates with fixed channel-production rate

Abstract

Polar codes are a class of error-correcting codes that provably achieve the capacity of practical channels under the low-complexity successive-cancellation flip (SCF) decoding algorithm. However, the SCF decoding algorithm has a variable execution time with a high (worst-case) decoding latency. This characteristic poses a challenge to the design of receivers that have to operate at fixed data rates. In this work, we propose a multi-threshold mechanism that restrains the delay of a SCF decoder depending on the state of the buffer to avoid overflow. We show that the proposed mechanism provides better error-correction performance compared to a straightforward codeword-dropping mechanism at the cost of a small increase in complexity. In the region of interest for wireless communications, the proposed mechanism can prevent buffer overflow while operating with a fixed channel-production rate that is 1.125 times lower than the rate associated to a single decoding trial.