Performance improvement of FSO system using multi‐pulse pulse position modulation and SIMO under atmospheric turbulence conditions and with pointing errors. Issue 4 (1st July 2018)

• Record Type: Journal Article
• Authors: Ismail, Tawfik; Leitgeb, Erich; Ghassemlooy, Zabih; Al‐Nahhal, Mohamed
• Is Part Of: IET networks. Volume 7:Issue 4(2018)
• Page Start: 165
• Page End: 172
• Publication Date: 2018-07-01
• Subjects: pulse position modulation -- telecommunication network reliability -- atmospheric turbulence -- wireless channels -- Monte Carlo methods -- optical communication -- optical links -- MIMO communication -- free‐space optical communication; Gamma–Gamma turbulence channel -- moderate turbulence regimes -- strong atmospheric turbulence regimes -- link average symbol error rate -- ASER -- outage probability -- PE -- system outage -- turbulence effects -- multiple‐output system -- optimal values -- system parameters -- FSO system -- multipulse pulse position modulation -- atmospheric turbulence conditions -- free space optics communication links -- pointing error effects -- size 0.5 m -- size 0.2 cm -- size 2.0 km -- size 3.0 km -- size 4.0 km -- size 5.0 km -- size 1.0 km; Computer network architectures -- Periodicals; Computer network protocols -- Periodicals; Information networks -- Periodicals; Telecommunication systems -- Periodicals; 004.605
• DOI: 10.1049/iet-net.2017.0203
• Languages: English
• ISSNs: 2047-4954

Abstract

Abstract : Free space optics (FSO) communication links are impaired by the fading due to turbulence and misalignment. In this paper, we theoretically analyze the pointing error effects on performance of FSO systems using multi‐pulse pulse position modulation (MP‐PPM) over the Gamma‐Gamma turbulence channel. We consider the moderate and strong atmospheric turbulence regimes with the combined effect of the pointing errors (PEs), and study the link average symbol error rate (ASER) and the outage probability. The numerical results are presented to show the impact of the pointing error on the ASER and the system outage. However, to overcome the channel degradation resulting from the turbulence effects and the PE, the single‐input multiple‐output (SIMO) system with maximal ratio combining (MRC) diversity is used. Exact close‐form expressions for ASER and outage probability are derived and verified by using Monte Carlo simulation. We concluded that the optimal values of the system parameters are, the transmitted power is 20 dBm, jitter variance should be less than 0.5 m and laser beam width equals 0.2 cm. These values are significantly reduced the impacts of misalignment and fading whereas outage probability is less than at maximum jitter variance.