Yeşilkaya, AnılBasar, ErtugrulMiramirkhani, FarshadPanayırcı, ErdalUysal, MuratHaas, Harald2019-06-272019-06-272017920090-67781558-08570090-67781558-0857https://hdl.handle.net/20.500.12469/329https://doi.org/10.1109/TCOMM.2017.2699964Visible light communications (VLC) is a promising and uncharted new technology for the next generation of wireless communication systems. This paper proposes a novel generalized light emitting diode (LED) index modulation method for multiple-input-multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM)-based VLC systems. The proposed scheme avoids the typical spectrum efficiency losses incurred by time- and frequency-domain shaping in OFDM signals. This is achieved by exploiting spatial multiplexing along with LED index modulation. Accordingly real and imaginary components of the complex time-domain OFDM signals are separated first then resulting bipolar signals are transmitted over a VLC channel by encoding sign information in LED indexes. As a benchmark we demonstrate the performance analysis of our proposed system for both analytical and physical channel models. Furthermore two novel receiver designs are proposed. Each one is suitable for frequency-flat or selective channel scenarios. It has been shown via extensive computer simulations that the proposed scheme achieves considerably better bit error ratio versus signal-to-noise-ratio performance than the existing VLC-MIMO-OFDM systems that use the same number of transmit and receive units [LEDs and photo diodes (PDs)]. Compared with the single-input single-output (SISO) DC biased optical (DCO)-OFDM system both spectral efficiency and DC bias can be doubled and removed respectively simply by exploiting a MIMO configuration.eninfo:eu-repo/semantics/openAccessVisible light communications (VLC)Multiple-input-multiple-output (MIMO) systemsOrthogonalArticle34293441865WOS:00041100610001810.1109/TCOMM.2017.26999642-s2.0-85029509430Q1Q1