Design and Optimization of Sandwich-Type Synchronization Sequence for Optical Wireless Communication With a Photon-Counting Receiver

This work aims to optimize the synchronization sequence for optical wireless communication with a photoncounting receiver. We propose a "Sandwich" structure of the synchronization sequence including two equilong RANDOM parts on both ends and a 1 -0 alternate part between them. We investigate the synchronization error event and analyze its statistical characteristics up to the second order. Based on the second-order properties, we propose an upper bound on the synchronization mean squared error (MSE) via Gaussian approximation. Furthermore, we optimize the synchronization sequence based on the upper bound, subject to the constraint that the probability of deviating even symbols is lower than a certain threshold. Numerical results on the correlation show the accuracy of statistical properties up to the second order, as well as the accuracy of Gaussian approximation. Moreover, it is numerically demonstrated that the optimized sequence obtained from the upper bound is close to that obtained from the real synchronization MSE. Compared with pure random 0 -1 sequence, m-sequence, Gold sequence, and Barker-like sequence, the synchronization MSE can be significantly reduced.