This paper proposed an analytical approach to evaluate the timing jitter’s impairment to the ergodic capacity and outage performance of an on-off keying wireless optical link, where the compound channel consists of Gamma–Gamma turbulence and pointing errors. Due to the complexity in deducing ergodic capacity, the closed-form bounds are developed, as well as the asymptotic limit. Meanwhile, the Gaussian–Hermite polynomial approximation is exploited to obtain the closed-form expression of outage probability in series. It has been verified by both theoretical results and the Monte-Carlo simulations that the timing jitter leads to a restriction of the ergodic capacity, even with tremendous transmitting power. In the meantime, small timing jitters could be endurable in the analysis of outage probability, whereas the large timing jitters diverge from the lower ones.
An analytical approach is proposed to evaluate the impact of timing jitter on the error performance of the L-ary pulse position modulation (L-PPM) free-space optical (FSO) link, under the gamma–gamma (ΓΓ) turbulence with pointing errors. The expression of the conditional symbol error rate (SER) for a certain timing jitter is developed while the Gaussian–Hermite polynomial approximation is utilized to derive the closed-form expression of the average SER by the jitter’s variance. It is discovered that the timing jitter contributes to an error floor on the SER in both Monte–Carlo simulations and the theoretical results. Also, the jitter with small variance could be tolerable. What is more, the PPM system with lower order is more sensitive to the timing jitter than the higher ones.