A Novel SM-Based Indoor VLC System with Index Modulation

Abstract

Spatial modulation (SM), as a simple case of multiple-input multiple-output (MIMO) technology, has been proposed for high data rate and low complexity transmission in indoor visible light communication (VLC) system. However, in SM VLC system, the transmit LED is randomly activated by the spatially modulated information bits. Due to the possible poor channel condition of the active LED, error transmission will occur and cause a significant performance degradation in the SM VLC system. In this paper, to avoid the poor channel selection of the SM scheme, a novel SM with index modulation (SM-IM) based indoor VLC system has been proposed. For the proposed scheme, the active LED index and the modulated symbol are jointly transmitted on one symbol via the best VLC channel and the receiver complexity can be significantly reduced. With the employment of IM, significant performance improvement can be achieved, compared to the traditional SM VLC system. The effect of the elevation angle of the photodetector (PD) in the SM-IM based VLC system is also investigated.