Performance Improvement in Subcarrier QAM Free Space Optical Links in the Presence of Atmospheric Turbulence and Pointing Error with Spatial Diversity and Beam Optimization
نویسندگان
چکیده
Free-space optical communication suffers from irradiance variations caused by random atmospheric temperature fluctuations and pointing error due to jitter and misalignment between transmitter and receiver. In this paper, the simulation results for the average symbol error rate performance of Free Space Optical links over gamma-gamma turbulence fading channels in the presence of pointing error with subcarrier QAM are studied and numerical results are obtained using spatial diversity and beam optimization. The received signal at the receivers is combined using maximal ratio combining. Furthermore, optimum beamwidth is calculated taking into account various metrics such as the electrical signal-to-noise ratio, the normalized jitter, and the SER. The results obtained can be a useful outcome for FSO system designers in order to limit pointing error effects and achieve an optimum performance. Index Terms — Diversity Reception, Free-space optics, Fading, MRC, Pointing error, QAM
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