scholarly journals Performance Analysis of Optical Spatial Modulation in Atmospheric Turbulence Channel †

Photonics ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 53 ◽  
Author(s):  
Hammed Olanrewaju ◽  
John Thompson ◽  
Wasiu Popoola
Keyword(s):  
Atmospheric Turbulence ◽  
Symbol Error Rate ◽  
Spatial Multiplexing ◽  
Spatial Modulation ◽  
Closed Form Expression ◽  
Channel Fading ◽  
Free Space Optical ◽  
Error Performance ◽  
Receive Diversity ◽  
Space Optical Communication

In this paper, spatial pulse position modulation (SPPM) is used as a case study to investigate the performance of the optical spatial modulation (SM) technique in outdoor atmospheric turbulence (AT). A closed-form expression for the upper bound on the asymptotic symbol error rate (SER) of SPPM in AT is derived and validated by closely-matching simulation results. The error performance is evaluated in weak to strong AT conditions. As the AT strength increases from weak to strong, the channel fading coefficients become more dispersed and differentiable. Thus, a better error performance is observed under moderate-to-strong AT compared to weak AT. The performance in weak AT can be improved by applying unequal power allocation to make free-space optical communication (FSO) links more distinguishable at the receiver. Receive diversity is considered to mitigate irradiance fluctuation and improve the robustness of the system to turbulence-induced channel fading. The diversity order is computed as half of the number of detectors. Performance comparisons, in terms of energy and spectral efficiencies, are drawn between the SPPM scheme and conventional MIMO schemes such as repetition coding and spatial multiplexing.

scholarly journals Performance Analysis of Optical Spatial Modulation in Atmospheric Turbulence Channel

2018 ◽  
Author(s):  
Hammed G. Olanrewaju ◽  
John Thompson ◽  
Wasiu O. Popoola
Keyword(s):  
Atmospheric Turbulence ◽  
Symbol Error Rate ◽  
Spatial Multiplexing ◽  
Spatial Modulation ◽  
Closed Form Expression ◽  
Channel Fading ◽  
Error Performance ◽  
Form Expression ◽  
Receive Diversity

In this paper, spatial pulse position modulation (SPPM) is used as a case study to investigate the performance of the optical spatial modulation (SM) technique in outdoor atmospheric turbulence (AT). A closed-form expression for the upper bound on the asymptotic symbol error rate (SER) of SPPM in AT is derived and validated by closely-matching simulation results. The error performance is evaluated in weak to strong AT conditions. As the AT strength increases from the weak to strong, the channel fading coefficients become more dispersed and differentiable. Thus, a better error performance is observed under moderate-to-strong AT compared to weak AT. The performance in weak AT can be improved by applying unequal power allocation to make FSO links more distinguishable at the receiver. Receive diversity is considered to mitigate irradiance fluctuation and improve the robustness of the system to turbulence-induced channel fading. The diversity order is computed as half of the number of detectors. Performance comparisons, in terms of energy and spectral efficiencies, are drawn between the SPPM scheme and conventional MIMO schemes such as repetition coding and spatial multiplexing.

scholarly journals Intensity Distribution of Partially Coherent Array Finite Airy Beams Propagating in Atmospheric Turbulence

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Long Jin ◽  
Zirui Zhang ◽  
Nuo Wang ◽  
Zixin Liu ◽  
Yuwei Deng ◽  
...  
Keyword(s):  
Atmospheric Turbulence ◽  
Cross Sections ◽  
Atmospheric Environment ◽  
Closed Form Expression ◽  
Free Space Optical ◽  
Truncation Parameter ◽  
Partially Coherent ◽  
Space Optical Communication ◽  
Turbulence Factor ◽  
Airy Beams

Based on the extended Huygens–Fresnel integral and the Rytov phase structure function, the closed-form expression of a partially coherent array finite Airy beams (PCAFABs) cutting through the Kolmogorov atmospheric turbulence is derived in the space domain under the paraxial approximation. The characteristics of the PCAFABs evoluting in the atmospheric environment are investigated in detail on the basis of the derived wave propagation formulae. We mainly illustrate the intensity profile of this beam changed with the truncation parameter, coherence length, and turbulence factor at several cross sections of the atmospheric space by means of numerical figures. It is convinced that the present concept and derived conclusions will provide useful exploration for learning the optical properties of the PCAFABs transmitting in the atmospheric turbulence, especially for free-space optical communication area.

An investigation of 16-QAM signal transmission over turbulent RoFSO link modeled by gamma–gamma distribution

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Abhishek Tripathi ◽  
Shilpi Gupta ◽  
Abhilash Mandloi ◽  
Gireesh G Soni
Keyword(s):  
Gamma Distribution ◽  
Free Space ◽  
Signal Transmission ◽  
Channel Modeling ◽  
Symbol Error Rate ◽  
Average Error ◽  
60 Ghz ◽  
Free Space Optical ◽  
Error Vector Magnitude ◽  
Space Optical Communication

AbstractThis paper outlines the performance of a 10 Gbit/s rectangular 16-quadrature amplitude modulation–based radio over free space optical communication system. Here, 60 GHz radio frequency–modulated signal is propagated through a 1550-nm free space optical link. The gamma–gamma distribution is used for the channel modeling of weak to strong atmospheric turbulence. The reported constellation plots and eye patterns are attributed to impairment factors in adverse conditions of atmosphere. The evaluation is carried out that the variation in average error vector magnitude in the range of 1.45–1.63% and equivalent symbol error rate of 0.019–0.023 are obtained for a clear atmosphere compared to the turbulent link of 0.2–1 km, respectively.

scholarly journals BER analysis of amplify-and-forward relaying FSO systems using APD receiver over strong atmospheric turbulence channels

2019 ◽  
Vol 9 (5) ◽  
pp. 3678
Author(s):  
Duong Huu Ai ◽  
Van Loi Nguyen
Keyword(s):  
Atmospheric Turbulence ◽  
Closed Form Expression ◽  
Free Space Optical ◽  
Amplify And Forward ◽  
Transmission Distance ◽  
Link Distance ◽  
Optimal Value ◽  
Atmospheric Loss ◽  
The Impact ◽  
Relay Stations

<span lang="EN-US">In this paper, we theoretically analyze the performance of amplify-and-forward (AF) serial relaying free-space optical (FSO) systems using avalanche photodiodes (APD) and subcarrier quadrature amplitude modulation (SC-QAM) over strong atmospheric turbulence channels modelled by gamma-gamma distribution. Closed-form expression for average bit error rate (BER) of system is theoretically derived talking into account APD shot noise, thermal noise as well as the impact of atmospheric loss and turbulence. The numerical results show that using AF relay stations can extend the transmission distance and help to improve performance of FSO system significantly when compared with the direct transmission. Moreover, the selection of APD gain value is indispensable to the system performance. The proposed system could be achieved the best performance by selecting an optimal APD gain value. In addition, the optimal value of APD gain also significantly depends on various conditions, such as link distance, the number of relay stations and APD receiver noise.</span>

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