Channel estimation for asymmetrically clipped optical orthogonal frequency division multiplexing optical wireless communications

A novel channel estimation method for asymmetrically clipped optical orthogonal frequency division multiplexing-based optical wireless communications systems is proposed. Different from the superimposed sequence used in traditional methods, the local matrix and superimposed periodic training are designed rationally. Furthermore, the channel impulse response coefficient of indoor optical wireless diffuse channel can be estimated exactly. The proposed method is not only accurate and simple, but can also allocate time and power flexibly, and improves the bandwidth efficiency.