Rate-Adaptive OFDM MIMO VLC System

In this paper, we investigate link adaptation for an orthogonal frequency division multiplexing (OFDM)-based multiple-input multiple-output (MIMO) visible light communication (VLC) system. The MIMO system under consideration employs repetition coding, therefore all the transmitters emit the same information. We propose a rate adaptation algorithm where the modulation size is selected among the available constellation sets. The receiver first calculates the instantaneous signal-to-noise ratio per sub-carrier, then determines the maximum constellation size on each subcarrier that can be supported while satisfying a predefined target bit error rate. Our numerical results reveal that a peak data rate of more than 1.14 Gbits/sec can be achieved using LEDs with cut-off frequency of 10 MHz in typical office spaces.