Differential Signalling in Free-Space Optical Communication Systems

Abstract

In this paper, we review the differential signalling techniques and investigate its implementation of in free-space optical (FSO) communication systems. The paper is an extended version of our previous works, where the effects of background noise, weak turbulence and pointing errors (PE) were investigated separately. Here, for the first time, we present a thorough description of the differential signalling scheme including for combined effects. At first, we present an extension of the analysis of differential signalling to the case of moderate to strong atmospheric turbulence. Next, we investigate a more general case where both channel turbulence and PE are taken into consideration. We provide closed-form expressions for the optimal detection threshold and the average bit-error-rate, and present a set of numerical results to illustrate the performance improvement offered by the proposed differential signalling under various turbulence and PE conditions. differential signaling to mitigate pointing errors effect in an FSO communication link. One of the authors, M.M.A. was supported by the PhD studentship from Northumbria University. The work was also supported by the The European project H2020 MSC ITN no. 764461 (VISION) and CTU project SGS17/182/OHK3/3T/13. Conflicts of Interest:The authors declare no conflict of interest. Author Contributions: M.M.A. and M.R.B. carried out the mathematical analysis and simulation; Z.G. and S.Z. proofread and confiremed the analysis; M.-A.K. and M.P.J.L. contributed to the theory material.Acknowledgments: Portions of this work were presented at the IEEE International Conference on Communications ICC in 2016 (ICC2016), using differential signaling to mitigate pointing errors effect in an FSO communication link. One of the authors, M.M.A. was supported by the PhD studentship from Northumbria University. The work was also supported by the The European project H2020 MSC ITN no. 764461 (VISION) and CTU project SGS17/182/OHK3/3T/13. Conflicts of Interest:The authors declare no conflict of interest.

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