Open AccessPerformance improvement of NOMA visible light communication system by adjusting superposition constellation: a convex optimization approach
Author(s) -
Hao Ren,
Zixiong Wang,
S.H. Du,
Yongfeng He,
Jian Chen,
Shiying Han,
Yu Chen,
Chao Xu,
Jinlong Yu
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.029796
Subject(s) - visible light communication , bit error rate , superposition principle , spectral efficiency , computer science , optics , convex optimization , noma , constellation , signal to noise ratio (imaging) , physics , power (physics) , regular polygon , electronic engineering , algorithm , telecommunications , mathematics , engineering , telecommunications link , decoding methods , beamforming , geometry , light emitting diode , quantum mechanics , astronomy
Non-orthogonal multiple access (NOMA) can increase the overall spectral efficiency of visible light communication (VLC) system. In this paper, we proposed a novel scheme to improve the bit error rate (BER) performance of a two-user NOMA VLC system by adjusting superposition constellation. The corresponding closed-form BER expressions are derived. Convex optimization is used to find the optimal parameters of the adjusted superposition constellation, where the overall BER is minimized. The BER performances are evaluated by theoretical analysis, Monte-Carlo (MC) simulation and experiment. The results illustrate that 8.9-dB and 8.1-dB signal-to-noise ratios (SNRs) are reduced to achieve BER of 10 -3 for the two users, whose power allocation coefficients are 0.6 and 0.4, respectively.