Performance Analysis of MIMO Techniques for a Pyramid Receiver in an Indoor MIMO-VLC System

Authors : Aamir Ullah KHAN, Sultan ALDIRMAZ ÇOLAK, Yasin ÇELİK

Pages : 942-955

Doi:10.16984/saufenbilder.849408

View : 15 | Download : 6

Publication Date : 2022-10-20

Article Type : Research Paper

Abstract :In an indoor multiple-input multiple-output insert ignore into journalissuearticles values(MIMO); visible light communication insert ignore into journalissuearticles values(VLC); system, line of sight insert ignore into journalissuearticles values(LoS); channel links are present between a light-emitting diode insert ignore into journalissuearticles values(LED); based transmitter and a photodetector insert ignore into journalissuearticles values(PD); based receiver. The PDs in the receiver are closely packed resulting in a high channel correlation. To overcome channel correlation and improve the performance of the MIMO-VLC system, angle diversity receivers insert ignore into journalissuearticles values(ADRs); are commonly employed. The channel matrix entries depend on the normal vectors of the PDs, which in turn depend on the elevation angle insert ignore into journalissuearticles values(EA); of the PDs. Thus, by having normal vectors pointing in different directions, the channel correlation can be considerably reduced. This paper considers a special type of ADR called pyramid receiver insert ignore into journalissuearticles values(PR); and employs a 4x4 MIMO-VLC system. In this paper, different MIMO algorithms such as repetition coding insert ignore into journalissuearticles values(RC); and spatial multiplexing insert ignore into journalissuearticles values(SMP); are considered to exhibit and compare the bit-error-rate insert ignore into journalissuearticles values(BER); performance of the fixed and variable EA MIMO-VLC systems. The results show that an SMP-employed MIMO-VLC system outperforms the RC-employed MIMO-VLC system. SMP results in an spatial multiplexing gain that varies linearly with the number of LEDs whereas RC does not yield any spatial multiplexing gain. To attain the same spectral efficiency i.e. 4 bit/s/Hz, a larger signal constellation size is required for RC employed MIMO-VLC system to achieve the same BER as of an SMP employed MIMO-VLC system. Similarly, the BER performance of variable EA MIMO-VLC systems is better as compared to fixed EA MIMO-VLC systems.
Keywords : angle diversity receiver, optical wireless communication, pyramid receiver, visible light communication