Optical MIMO-OFDM with Generalized LED Index Modulation

Anil Yesilkaya, Ertugrul Basar, Farshad Miramirkhani, Erdal Panayirci, Murat Uysal, Harald Haas

Research output: Contribution to journalArticlepeer-review


Visible 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.

Original languageEnglish (US)
Article number7915761
Pages (from-to)3429-3441
Number of pages13
JournalIEEE Transactions on Communications
Issue number8
StatePublished - Aug 2017


  • LED index modulation
  • Visible light communications (VLC)
  • maximum-a-posteriori probability (MAP) estimator
  • multiple-input-multiple-output (MIMO) systems
  • optical-spatial modulation (OSM)
  • orthogonal frequency division multiplexing (OFDM)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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