Open AccessExpectation-maximization-based channel estimation algorithm for OFDM visible light communication systems
Author(s) -
Mohamad Yusoff Alias,
Nazaruddin Omar,
Mohd Kamarulzamin Salleh,
Yaseein Soubhi Hussein,
Ayad Atiyah Abdulkafi
Publication year - 2018
Publication title -
international journal of engineering and technology
Language(s) - English
Resource type - Journals
ISSN - 2227-524X
DOI - 10.14419/ijet.v7i4.15994
Subject(s) - visible light communication , minimum mean square error , orthogonal frequency division multiplexing , estimator , algorithm , computer science , bit error rate , expectation–maximization algorithm , channel (broadcasting) , demodulation , mathematics , maximum likelihood , telecommunications , statistics , engineering , light emitting diode , electrical engineering
The tremendous growth of indoor communication requires increased capacity and appropriate quality of services. Visible light communica-tion (VLC) is a green technology that shows great promise in terms of its ability to meet the demand for communication services. Orthogo-nal frequency division multiplexing (OFDM) enables VLC to provide a higher data rate and to combat inter-symbol interference. However, an accurate and efficient channel estimation method is needed for coherent demodulation at the receiver end of an OFDM system. In this paper, a new algorithm for OFDM-based VLC systems is proposed. The algorithm is based on expectation maximization and is called the expectation maximization for visible light communication (EM-VLC) algorithm. The algorithm is implemented to find the maximum-likelihood (ML) estimation of the channel impulse response and to find unknown parameters. In addition, a low-rank minimum mean square error (lr-MMSE) estimator algorithm is developed and its performance is compared with least squares (LS) and minimum mean square error (MMSE) estimators. The proposed EM-VLC algorithm improves the performance of OFDM VLC systems by significantly reducing the bit error rate (BER) and consequently increasing system throughput. The simulation results demonstrate that the EM-VLC algorithm outper-forms the three channel estimation algorithms, LS, MMSE and lr-MMSE.