Performance Analysis of Short Packets in NOMA VLC Systems

In this paper, we propose a theoretical framework for analyzing the performance of the short-packet communication (SPC) in a downlink non-orthogonal multiple access (NOMA) visible light communication (VLC) system in which one light emitting diode (LED) communicates with two single-photodiode users. The analytical expression of the block error rate (BLER) is approximated by Gaussian-Chebyshev quadrature method, based on which the reliability, throughput, and latency expressions are deduced. Further, we jointly optimize power allocation coefficients and transmission rates to maximize sum throughput of the SPC-NOMA VLC system. The numerical results show that (i) our proposed system well satisfies the stringent requirements of the ultra-reliable and low latency communication (URLLC) at signal-to-noise ratio (SNR) larger than 130 dB; (ii) SPC-NOMA VLC systems outperform SPC- orthogonal multiple access (OMA) VLC systems in terms of reliability, latency, and throughput; (iii) the impacts of block-length, power allocation coefficients, transmission rates, and LED semi-angle are examined.