Aggregate capacity optimization algorithm for large pool size multi-mode orbital angular momentum free space optical beam communication

This paper proposes a simple iterative algorithm to determine the optimum (in terms of the system capacity) set of multiple orbital angular momentum (OAM) modes over Free space optical (FSO) communication beam for a given receiver radius using generalized channel efficiency matrix. The optimum set is the same as the obtained set from exhaustive search that was previously proposed in the literature but has a much lower complexity. The proposed algorithm is especially efficient for large number of modes. The complexity reduction is in the order of 2N∕N2 when compared to the exhaustive search, where N is the pool size of available modes.