Free-space optical (FSO) communication is highly sensitive to atmospheric turbulence. The gamma-gamma model has been used as it describes the behaviour of a wide range of atmospheric conditions with a good agreement. In this study, closed-form expressions for calculating the bit error rate, the outage probability and ergodic capacity have been proposed for the gamma-gamma atmospheric turbulence channel with pointing errors. The performance of FSO for three turbulence mitigation techniques: aperture averaging, multiple-input/single-output and Bose-Chaudhuri-Hocquenghem block code have been investigated. Analytical results are depicted by using a realistic set of system parameter values, to lend a helpful insight into the performance of source-destination link distance of 10km in FSO communication system under atmospheric turbulence conditions.