An initialization scheme for blind equalization in VLC systems

Inter-symbol interference (ISI) in visible light communication (VLC) systems has been considered as a major problem which seriously deteriorates system performance. Constant modulus algorithm (CMA) is a widely adopted blind equalization scheme to eliminate ISI in practice due to its computational simplicity and effectiveness. This paper proposed an initialization scheme for CMA based on received signal power. The similarity level of the channels is measured by the difference between the current received power and the pre-stored received power. If the difference appears in a specific range, the pre-stored weight vector already calculated can be used for initialization. Compared with the center-spike initial setting, the proposed scheme can accelerate the convergence rate of CMA and ensure that the equalizer will converge to a stable equilibrium near a desired global minimum.