Estimation of NLOS optical wireless communication channels with laser transmitters

We propose channel estimation for the optical wireless scattering channel with a Laser Diode transmitter based on sparse pilots. For channel taps {h_n}^L_n=0, the proposed estimation approach consists of two steps, the estimation of the real part Re(h_ih^*_j) in the first step and the estimation of {h_n}^L_n=0 in the second step. Numerical results show that, compared with conventional channel estimation approach based on second-order moments, the proposed approach shows slight performance gain, and less than one tenth of the computational complexity.