Improved OFDM Allocation Scheme for Crosstalk Mitigation in Multiple Free-Space Optical Interconnection Links

This study considers the use of the dc-biased optical orthogonal frequency-division multiplexing (DCO-OFDM) resource allocation technique to mitigate the crosstalk effect in a free-space optical interconnect (FSOI) system. The optimization of DCO-OFDM parameters is a promising approach for reducing the crosstalk effect of dense FSOI. However, determining the optimal DCO-OFDM subcarrier allocation and the corresponding bit-and-power loading requires to solve an intractable discrete optimization problem, which is nonconvex and difficult to solve explicitly. In this study, we use cross-entropy optimization (CEO) to address this problem. Simulation results reveal that the proposed CEO-based allocation scheme obtains better bit rates that are less susceptible to the crosstalk effect than the traditional greedy-based algorithm and other state-of-the-art stochastic optimization techniques.