Mao Lei, Liang Zhangtao, Zuo Zhiyue, Zhang Hang, Wang Yijun
School of Automation, Central South University, Changsha 410083, China.
Entropy (Basel). 2025 Sep 22;27(9):990. doi: 10.3390/e27090990.
A continuous-variable quantum key distribution (CVQKD) can be realized over the seawater channel, but the transmission of quantum signals in seawater media exhibits significant attenuation effects. Therefore, we propose an -symbol amplitude and phase shift keying (-APSK) modulation scheme to enhance the transmission performance of the CVQKD over the seawater channel. Specifically, an optimal -APSK modulation scheme is designed based on the principle of maximizing the minimum Euclidean distance (MED). The simulation results show that the CVQKD protocol based on -APSK modulation achieves a longer transmission distance over the seawater channel compared to the Gaussian modulation protocol. Additionally, increasing the value of simultaneously expands the number of rings in the constellation diagram, further enhancing the communication distance. This study transfers modulation methods from the field of classical communications to the field of quantum communications, achieving a substantial improvement in communication distance and thereby promoting the integration of quantum communications and classical communications.
连续变量量子密钥分发（CVQKD）可以在海水信道上实现，但量子信号在海水介质中的传输表现出显著的衰减效应。因此，我们提出一种 - 符号幅度和相移键控（-APSK）调制方案，以提高CVQKD在海水信道上的传输性能。具体而言，基于最大化最小欧几里得距离（MED）的原理设计了一种最优的 -APSK调制方案。仿真结果表明，与高斯调制协议相比，基于 -APSK调制的CVQKD协议在海水信道上实现了更长的传输距离。此外，增加 的值同时会扩大星座图中的环数，进一步提高通信距离。本研究将调制方法从经典通信领域转移到量子通信领域，实现了通信距离的大幅提升，从而推动了量子通信与经典通信的融合。
