Generalized Selection Multiuser Scheduling for the MIMO FSO Communication System and Its Performance Analysis

Abstract

This paper analyzes the impact of generalized selection multiuser scheduling on the performance of the multiple-input-multiple-output (MIMO) free-space optical (FSO) communication system. We consider a general scenario that the point-to-multipoint system consists of a central transmitter equipped with K aperture groups containing M transmit apertures and K users equipped with N receive apertures communicating over gamma-gamma turbulence FSO channels. For the MIMO links between the central node and user, we derive the combining signal-to-noise ratio (SNR) distributions of MIMO repetition coding and MIMO transmit laser selection. Then, a statistics analysis is presented for the multiuser diversity scheme in which the user with the kth best combining SNR is selected. Based on the analysis, the closed-form expressions of the outage probability are derived, and the diversity benefit provided by the channel fluctuations is further discussed. Numerical results verify the accuracy of these analytical results.