Low-complexity Polar Decoding with adaptive threshold

Although the SCF algorithm can significantly avoid the impact of accumulated errors in the decoding process by flipping the first erroneous bit of the traditional SC algorithm, the computational complexity of that will also increase. Based on this disadvantage, a new polar code SCF method based on effective flip bits has been proposed, which can effectively reduce the computational complexity at low SNR by flipping the worst performing bits in the search channel. However, the limitation of this algorithm increases with the increase of SNR. In this letter, based on the limitation, an adaptive threshold is proposed to further reduce the complexity. The SCF-EF decoding algorithm under adaptive thresholds can effectively reduce unnecessary flipping of the original SCF decoding algorithm, and effectively reduce the complexity of the practical decoding operation, with the loss of the BLER performance can be negligible. Simulation results demonstrate that for practical code lengths (1024, 512), the adaptive SCF-EF(AD_EF) algorithm can achieve a complexity reduction in the range of 4% to 7% at SNR of 1.0/1.5dB with the loss of the BLER performance can be negligible.