Performance Evaluation of Log-normal And Negative Exponential Channel Modeling Using Various Modulation Techniques in OFDM-FSO Communication

Nitin Shankar Singh,Gurpartap Singh

doi:10.24297/ijct.v4i2c2.4189

Nitin Shankar Singh, Gurpartap Singh

Open Access

https://doi.org/10.24297/ijct.v4i2c2.4189

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Abstract

Free Space Optics (FSO) is one of the emerging technology which is thoroughly being popular and is basically using optical signals for the communication. The paper evaluates the bit error rate performance of the Free space Optics (FSO) system. To design a high performance communication link for the atmospheric FSO channel, it is of great importance to characterize the channel with proper model. The performance of the highly efficient, high data rate system is limited by the certain constraints like scintillation effects and atmospheric turbulence. The FSO communication system using Orthogonal Frequency Division Multiplexing (OFDM) technique which is known for its increased robustness against frequency selective fading, narrow-band interference and high channel efficiency. The performance of the modulation techniques- Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) and 8-PSK are studied in the Lognormal and Negative Exponential channel. The obtained results are the comparative study of Bit Error Rate (BER) vs. Signal to Noise Ratio (SNR), which is quite useful for analyse the system performance with different channel models for various modulation techniques.

Highlights

The Free Space Optics (FSO) systems are increasingly being considered as a suitable alternative technology for optical fiber networks, especially in areas where the deployment of optical fiber is not feasible and in underserved rural areas lacking broadband network connectivity
The log-normal model represents the weak regime specifications in the Orthogonal Frequency Division Multiplexing (OFDM)-FSO system, it is a continuous distribution in the region of weak fluctuations, the statics of the irradiance fluctuations have experimentally found to obey the log-normal distribution [16]
If there is a comparisonbetween the Log-normal distribution and Negative Exponential Distribution over the same signal to noise ratio (SNR) value from both the curves in Fig. 2 and Fig. 3 represents that data rate increases as per as the Bit Error Rate (BER) increases over the and same power for the Log-normal distribution, analyses that OFDM technique is efficiently used with the FSO system, with Binary Phase-shift keying (BPSK) modulation

Summary

Introduction

The Free Space Optics (FSO) systems are increasingly being considered as a suitable alternative technology for optical fiber networks, especially in areas where the deployment of optical fiber is not feasible and in underserved rural areas lacking broadband network connectivity. This paper covers the free space optical communication system analysis over BER vs SNR parameters for log normal and negative exponential channel modeling through various modulation techniques. The two distribution models discussed here with different modulation techniques (i.e. BPSK, QPSK and 8-PSK) are basically presented to analyse the performance of OFDM-FSO system in the weak regime and strong regime of the atmospheric turbulence modelling.

Results

Conclusion