Error analysis of L-PPM modulated MIMO based multi-user NOMA-VLC systemwith perfect and imperfect SIC
Vipul Dixit, Atul Kumar
Abstract
By offering a wide license-free spectrum, visible light communication (VLC) has emerged as a game-changing technology for networks beyond 5G. In this study, the multiple-input multiple-output (MIMO) technology is combined with a non-orthogonal multiple access VLC (NOMA-VLC) system to provide a reliable error-free high data rate network for multi-user scenarios. A generalized <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>L</mml:mi> </mml:math> -PPM modulated MIMO based multi-user NOMA-VLC system with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>M</mml:mi> <mml:mo>×</mml:mo> <mml:mi>N</mml:mi> </mml:math> line-of-sight connections for each user is presented. Considering a practical scenario of imperfect successive interference cancellation, a novel, to the best of our knowledge, closed form formulation of error probability for the proposed system is obtained. This study also includes a comprehensive analysis of two-user and three-user <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>L</mml:mi> </mml:math> -PPM modulated <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>2</mml:mn> <mml:mo>×</mml:mo> <mml:mn>2</mml:mn> </mml:math> MIMO-NOMA-VLC systems, and exact error probability expressions are derived. With the identical set of parameters, the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>L</mml:mi> </mml:math> -PPM modulated MIMO-NOMA-VLC system totally outperforms the on–off keying modulated MIMO-NOMA-VLC system. As the number of photodetectors per user increases, the error probability of the considered system decreases. An <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>L</mml:mi> </mml:math> -PPM modulated <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>2</mml:mn> <mml:mo>×</mml:mo> <mml:mn>2</mml:mn> </mml:math> MIMO based three-user NOMA-VLC system offers the best performance at a power allocation co-efficient of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mspace width="thinmathspace"/> <mml:mn>0.3</mml:mn> </mml:math> . The simulation results validate the derived error probability expressions.