Flexible-rate SIC-free NOMA for downlink VLC based on constellation partitioning coding

• Main Authors: Chen, Chen, Zhong, Wen-De, Yang, Helin, Du, Pengfei, Yang, Yanbing
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2019
• Subjects: Constellation Partitioning Coding; Visible Light Communication; Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/105590; http://hdl.handle.net/10220/50156; http://dx.doi.org/10.1109/LWC.2018.2879924
• Institution: Nanyang Technological University

Visible light communication (VLC) systems utilizing conventional superposition coding/successive interference cancellation (SPC/SIC)-based non-orthogonal multiple access (NOMA) suffer from the error propagation effect due to imperfect SIC. In this letter, we propose a flexible-rate SIC-free NOMA technique for downlink VLC systems, based on constellation partitioning coding (CPC) and uneven constellation demapping (UCD). By using CPC/UCD, SIC is not required and hence error propagation can be eliminated in NOMA-based VLC systems. Moreover, by selecting a proper bit allocation scheme, flexible-rate multiple access can be supported in the VLC system applying CPC/UCD based NOMA. Proof-of-concept two-user VLC experiments verify that, compared with conventional SPC/SIC-based NOMA, the bit error rate performance of the near user can be greatly improved by using CPC/UCD-based NOMA, and hence the effective power allocation ratio range can be substantially extended.