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量子密钥分发能够使得合法通信双方共享一组无条件安全的密钥。数据协调是量子密钥分发过程中非常重要的一个环节,能够对密钥分发过程中产生的错误进行纠错。低密度奇偶校验(LDPC)码是一种性能接近于Shannon极限的信道纠错码,适用于高效的数据协调。为了达到高的协调效率,需要根据信道的信噪比适当地选择最佳的LDPC码的码率。我们提出了一种适用于高斯调制连续变量量子密钥分发的码率可调的数据协调方案:当信道信噪比发生变化时,使用码率调整技术对数据协调过程中每一级LDPC码的码率进行适当地调整,从而确保数据协调的效率在一定信噪比变化范围内能够保持。
Quantum key distribution enables legitimate communications parties to share a set of unconditionally secure keys. Data reconciliation is a very important part of the quantum key distribution process, which can correct the errors generated in the key distribution process. Low Density Parity Check (LDPC) codes are channel error correction codes with performance close to the Shannon limit for efficient data reconciliation. In order to achieve high coordination efficiency, the optimal LDPC code rate needs to be appropriately selected according to the signal-to-noise ratio of the channel. We propose a data rate-adjustable data reconciliation scheme suitable for Gaussian modulated continuous-variable quantum key distribution. When the signal-to-noise ratio of the channel changes, the rate adjustment technique is used to estimate the data rate of each LDPC code The rate is properly adjusted to ensure that the efficiency of data reconciliation is maintained over a range of signal-to-noise ratios.