Sparsity-based Channel Estimation in Visible Light Communication

This paper considers a multi-user multiple-input multiple-output (MU-MIMO) visible light communication (VLC) interference channel system with massive light emitting diode (LED) arrays. Compared with the perfect channel state information (CSI), the sparse loss of channel is more realistic in VLC applications due to obstruction of the light, which may significantly degrade the performance of transmission. Hence, the robustness is a crucial issue. We estimate the transmitted signal and take the sparse loss into account for an indoor VLC system with imperfect CSI. The standard CVX method is used to minimize the ℓ1-norm that subjects to the constraints on the channel uncertainty and signal estimation. Moreover, considered the sparsity of channel imperfection, an iterative algorithm based on alternating direction method of multipliers (ADMM) is proposed to further solve the underlying estimation problem. Simulation results indicate that the iteration method offers higher robustness against channel uncertainty in different scenarios than the standard CVX method.