Adaptive least squares channel estimation for visible light communications based on tap detection

Visible light communication (VLC) is one of the promising technologies for future wireless communications and has attracted increasing research interest in recent years. In this paper, we propose an adaptive least squares (LS) channel estimation algorithm for VLC systems using the direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) scheme. The proposed algorithm is obtained by employing the tap detection that provides the maximum probability of correctly separating non-zero and zero-value channel taps, yielding significantly improved estimation performance. We prove that the Cramér–Rao lower bound of the proposed algorithm is lower than that of the conventional LS algorithm. Finally, numerical results demonstrate that the proposed algorithm achieves better performance in terms of the received constellation, mean squared error (MSE) and bit error rate (BER).