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In this paper, we present a new secure message transmission scheme using hyperchaotic discrete primary and auxiliary chaotic systems. The novelty lies on the use of auxiliary chaotic systems for the encryption purposes. We have used the modified Henon hyperchaotic discrete-time system. The use of the auxiliary system allows generating the same keystream in the transmitter and receiver side and the...
In this paper, we propose a hybrid radio over multi-mode/single-mode fibre and free space optics (RoMMF/SMF-FSO) system to enhance the 4th generation-long term evolution (4G-LTE) signal performance when used in local area access networks. A single mode fibre pigtailed gradient index lens is used to minimise the modal effect of the optical link at different turbulence strengths. The proposed system...
This paper experimentally investigates the performance of an FSO communications system by increasing the link length under an indoor laboratory controlled turbulence condition. A plane mirror is used to increase the link length by means of optical beam reflection. The experimental results show that the turbulence strength is highly dependent on the link length. The measured scintillation index (SI)...
In this paper, we present the experimental results forfree space optics (FSO) communication systems operating at visible and near infrared wavelengths (from 0.6 μm to 1.6 μm) under fog conditions. Different empirical fog models are typically used to characterize the fog attenuation of optical beam in FSO systems. A number of empirical fog models are evaluated in order to verify them experimentally...
In this paper, the attenuation of free space optical (FSO) communication systems operating at selected wavelengths of 0.83 μm, 1.31 μm and 1.55 μm in the controlled laboratory based fog and smoke environments are compared. The fog and smoke are generated and controlled homogeneously along the indoor atmospheric chamber of length 6 m. The experimental results from the selected wavelengths are compared...
In this paper, we compare the fog attenuation of free space optical (FSO) communication systems operating at infrared wavelengths of 830 and 1550 nm in the controlled laboratory based fog environment. The fog is generated and controlled homogeneously along the atmospheric chamber of length 5.5 m. The visibility (V) is measured to characterize the fog within the chamber using Koschmieder relationship...
This paper discuss the measurement setup and the appropriate method used for the data acquisition of the fog attenuation corresponding to the visibility (V) in an indoor laboratory based free space optical (FSO) chamber.
This paper outlines the experimental investigation of the fog effect on the bit error rate (BER) performance of the free space optical (FSO) communication link under a controlled laboratory environment. The link transmittance and the received signal Q-factor are measured against different levels of fog densities. The link visibility derived from fog attenuation measurement is used to characterize...
In this paper, the effect of turbulence and fog on the free space optical (FSO) communication systems for on-off-keying (OOK), pulse amplitude modulation (PAM) and subcarrier intensity modulation (SIM) based on binary phase shift keying (BPSK) is experimentally investigated. The experiment is carried out in a controlled laboratory environment where turbulence and fog could be generated in a dedicated...
This paper experimentally investigates and compares the performance of the free space optics system employing three different modulation schemes, on-off keying (OOK) with non-return-to-zero (NRZ) and return-to-zero (RZ) and the binary phase shift keying (BPSK) operating under the turbulent atmosphere. The received average signal is measured and used to characterize the strength of the turbulence....
The paper reports experimental results for the performance of a free space optical (FSO) communication link employing different modulation schemes under the influence of the atmospheric scintillation. A dedicated experimental atmospheric simulation chamber has been developed where weak and medium turbulence can be generated and its effect on the FSO link is investigated. The experimental data obtained...
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