Abstract
Recently, generalized light emitting diode (LED) index modulation scheme orthogonal frequency division multiplexing (GLIM-OFDM) was suggested to Li-Fi technology. GLIM-OFDM use channel state information in its estimator and consider channel known, which is not practical assumption. In this paper, considering the Li-Fi channel as a semi-static channel, the GLIM-OFDM estimator can use the previous channel information obtained from the previous OFDM frame. Then update its channel estate information dynamically with each OFDM frame. In this paper, we proposed time domain synchronous OFDM (TDS-OFDM) as a modulation technique for generalized LED. In this scheme, TDS operates over visible light communication channel to mitigate the inter-symbol interference by separating the complex TDS-OFDM signals into real and imaginary parts, then, exploiting the spatial multiplexing precept to transmit these signals through channel. Subspace orthogonal matching pursuit (SOMP) is used for the TDS-OFDM channel estimation. The suggested scheme performances based on computer simulation are explained in terms of BER performance and energy efficiency.