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

Fuente: arXiv
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Main Authors: Nguyen, Thang K., Pham, Thanh V., Le, Hoang D., Nguyen, Chuyen T., Pham, Anh T.
Format: Preprint
Published: 2024
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author Nguyen, Thang K.
Pham, Thanh V.
Le, Hoang D.
Nguyen, Chuyen T.
Pham, Anh T.
author_facet Nguyen, Thang K.
Pham, Thanh V.
Le, Hoang D.
Nguyen, Chuyen T.
Pham, Anh T.
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2408_02990
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Joint Design of Probabilistic Constellation Shaping and Precoding for Multi-user VLC Systems
Nguyen, Thang K.
Pham, Thanh V.
Le, Hoang D.
Nguyen, Chuyen T.
Pham, Anh T.
Systems and Control
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.
title Joint Design of Probabilistic Constellation Shaping and Precoding for Multi-user VLC Systems
topic Systems and Control
url https://arxiv.org/abs/2408.02990