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Enhanced Optical Quadrature Spatial Modulation for Indoor Visible Light Communications

This paper proposes an enhanced optical quadrature spatial modulation (EOQSM) scheme for indoor visible light communications. The proposed EOQSM scheme employs multiple signal constellations to improve the transmission rate, and only a few of multiple antennas are active according to the information bits. A dual layered modulation signal in a single symbol interval is transmitted, and the constellations of the modulation signals are redesigned. Compared with the traditional optical quadrature spatial modulation (OQSM) scheme, the bit error rate (BER) performance of the proposed EOQSM is further investigated. Simulation results show the superiority of the proposed EOQSM scheme under the condition of high signal-to-noise ratio (SNR).