BER analysis of optical space shift keying with gamma-gamma fading and pointing error

Space shift keying (SSK) is a technique where the antenna indices are used to transfer the information. In this paper, we investigate optical SSK (OSSK) system under the combined effects of atmospheric turbulence (AT) and pointing error (PE). We introduce an analytical framework to obtain average pair-wise error probability and average bit error rate of OSSK scheme. It is observed that for small PE jitter, degradation in error performance is very small, while for high PE jitter, the degradation is significantly high. Furthermore, the effect of PE with moderate and strong AT conditions is more dominant than the weak AT condition. Also, the performance of the OSSK system under strong and moderate AT regimes remains same, which makes the considered system nearly independent of turbulence between moderate to strong turbulence conditions.