High speed error correction for continuous-variable quantum key distribution with multi-edge type LDPC code

TL;DR

This paper demonstrates a GPU-accelerated high-speed error correction method for continuous-variable quantum key distribution using multi-edge type LDPC codes, significantly increasing decoding speed for real-time applications.

Contribution

The study introduces a GPU-based decoding approach for MET-LDPC codes, optimizing memory and algorithms to achieve over threefold speed improvements in error correction.

Findings

Achieved error correction speeds up to 30.39 Mbits/s for code rate 0.1.

Demonstrated parallel decoding of 64 codewords enhances throughput.

Optimized memory structure reduces computational complexity.

Abstract

Error correction is a significant step in postprocessing of continuous-variable quantum key distribution system, which is used to make two distant legitimate parties share identical corrected keys. We propose an experiment demonstration of high speed error correction with multi-edge type low-density parity check (MET-LDPC) codes based on graphic processing unit (GPU). GPU supports to calculate the messages of MET-LDPC codes simultaneously and decode multiple codewords in parallel. We optimize the memory structure of parity check matrix and the belief propagation decoding algorithm to reduce computational complexity. Our results show that GPU-based decoding algorithm greatly improves the error correction speed. For the three typical code rate, i.e., 0.1, 0.05 and 0.02, when the block length is $10^6$ and the iteration number are 100, 150 and 200, the average error correction speed can be respectively achieved to 30.39Mbits/s (over three times faster than previous demonstrations), 21.23Mbits/s and 16.41Mbits/s with 64 codewords decoding in parallel, which supports high-speed real-time continuous-variable quantum key distribution system.