Joint Design of Probabilistic Constellation Shaping and Precoding for Multi-user VLC Systems
<|reference_start|>Joint Design of Probabilistic Constellation Shaping and Precoding for Multi-user VLC Systems: 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.<|reference_end|>
@article{nguyen2024joint,
    title={Joint Design of Probabilistic Constellation Shaping and Precoding for
  Multi-user VLC Systems},
    author={Thang K. Nguyen, Thanh V. Pham, Hoang D. Le, Chuyen T. Nguyen and Anh
  T. Pham},
    journal={arXiv preprint arXiv:2408.02990},
    year={2024},
    archivePrefix={arXiv},
    eprint={2408.02990},
    primaryClass={eess.SY cs.SY}
}