Design of an efficient indoor visible light communication (VLC) system requires careful considerations on both illumination and communication aspects. Besides fundamental factors such as received power and signal-to-noise ratio (SNR) level, studies on mobility scenarios and link switching process must be done in order to achieve good communication link quality in such systems. In this paper, a comprehensive lighting configuration for efficient indoor VLC systems for supporting mobility and link switching with constraint on illumination, received power, and SNR is proposed. Full connectivity in mobility scenarios is required to make the system more practical. However, different from other literatures, our work highlights the significance of recognizing the main influences of field of view angle on the connectivity performance in the practical indoor scenarios. A flexible link switching initiation algorithm based on the consideration of relative received power with adaptive hysteresis margin is demonstrated. In this regard, we investigate the effect of the overlap area between two light sources with respect to the point view of the receiver on the link switching performance. The simulation results show that an indoor VLC system with sufficient illumination level and high communication link quality as well as full mobility and support link switching can be achieved using our approach.

This paper proposes an advanced multi-pulse multilight emitting diodes (LEDs) modulation technique to improve the efficiency for indoor visible light communication systems. The technique is referred to as spatial multiple pulse position modulation (SMPPM), and it is developed by combining a high spectral efficiency space shift keying (SSK) with a high energy efficiency multiple pulse position modulation (MPPM). During a symbol transmission, multiple active pulse slots and active LED indices are utilized as two degrees of freedom to modulate information which in turn provides the balance between the complexity, achievable spectral efficiency and energy efficiency. The analytical expression for symbol error rate (SER) of SMPPM in a multiple input multiple output system with multi-path propagation from reflection is derived theoretically using union bound technique and validated by means of Monte-Carlo simulations. Error performance of SMPPM is then evaluated extensively for different transceiver parameters and pulse configurations. Error rate distribution in a typical indoor workspace is plotted and analyzed. The SMPPM system achieves significantly higher spectral efficiency with respect to the conventional MPPM, SSK and spatial pulse position modulation (SPPM).

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