标题： 多用户 VLC 系统中概率星座成形与预编码的联合设计 显示英文标题

标题： Joint Design of Probabilistic Constellation Shaping and Precoding for Multi-user VLC Systems

摘要： 本文提出了一种联合设计概率星座塑形（PCS）和预编码的方法，以提升受信号幅度约束的多用户可见光通信（VLC）广播信道的总速率性能。在所提出的方案中，联合优化了每个用户的双极性$M$-脉冲振幅调制（$M$-PAM）符号的发送概率以及发送预编码矩阵，以提高总速率性能。由于目标函数的非凸性，该联合设计问题被证明是一个复杂的非凸问题。为了解决这个问题，采用了一种基于萤火虫算法（FA）的自然启发式启发式优化方法来求解原始非凸优化问题的局部最优解。然而，基于 FA 的方法计算复杂度较高。因此，我们提出了一种基于迫零（ZF）预编码的低复杂度设计方案，并使用交替优化（AO）方法解决。仿真结果显示，与传统的均匀信号设计方案相比，所提出的联合设计显著提高了总速率性能。此外，还提供了一些关于两种联合设计方案最优符号分布的见解。 显示英文摘要

摘要： This paper proposes a joint design of probabilistic constellation shaping (PCS) and precoding to enhance the sum-rate performance of multi-user visible light communications (VLC) broadcast channels subject to signal amplitude constraint. In the proposed design, the transmission probabilities of bipolar $M$-pulse amplitude modulation ($M$-PAM) symbols for each user and the transmit precoding matrix are jointly optimized to improve the sum-rate performance. The joint design problem is shown to be a complex non-convex problem due to the non-convexity of the objective function. To tackle the problem, the firefly algorithm (FA), a nature-inspired heuristic optimization approach, is employed to solve a local optima to the original non-convex optimization problem. The FA-based approach, however, suffers from high computational complexity. Therefore, we propose a low-complexity design based on zero-forcing (ZF) precoding, which is solved using an alternating optimization (AO) approach. Simulation results reveal that the proposed joint design with PCS significantly improves the sum-rate performance compared to the conventional design with uniform signaling. Some insights into the optimal symbol distributions of the two joint design approaches are also provided.