scholarly journals Accurate Evaluation of the Average Probability of Error of Pulse Position Modulation in Amplified Optical Wireless Communications under Turbulence

2019 ◽  
Vol 9 (4) ◽  
pp. 749 ◽  
Author(s):  
Anthony Boucouvalas ◽  
Nikos Sagias ◽  
Konstantinos Yiannopoulos
Keyword(s):  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Wireless Communication Systems ◽  
Pulse Position Modulation ◽  
Optical Wireless ◽  
Probability Of Error ◽  
Optical Wireless Communications ◽  
Average Probability ◽  
Good Agreement

We present exact and approximate results on the average probability of error (PER) for pulse position modulation (PPM) in pre-amplified optical wireless communication systems with diversity. The approximate results are obtained by combining a new mathematical formula that we derive for binary PPM and an existing formula that associates higher-order PPM PERs with their binary PPM counterpart. The approximate results are compared with the exact in weak, moderate, and strong turbulence, and it is demonstrated that they are in good agreement under all fading conditions. Moreover, the accuracy of the approximation improves with the optical signal-to-noise ratio and the number of diversity branches that are used, which correspond to implementation scenarios that are typically anticipated in practice.

Comparison between NRZ/RZ Modulation Techniques for Upgrading Long Haul Optical Wireless Communication Systems

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Ahmed Nabih Zaki Rashed
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Signal To Noise Ratio ◽  
Electrical Signal ◽  
Wireless Communication Systems ◽  
Optical Wireless Communication ◽  
Optical Wireless ◽  
Modulation Technique ◽  
Transmission Distance ◽  
Modulation Techniques

AbstractThis study has presented the complete comparison non return to zero (NRZ) and return to zero (RZ) modulation techniques for upgrading long haul optical wireless communication systems. Electrical signal to noise ratio is measured. Q-ranges factor are measured at the receiver side for different transmission distance from 500 to 1000  km. As well as the performance parameters of optical wireless communication systems are estimated at different transmission data rates with possible maximum transmission distance. NRZ modulation technique has outlined better performance than RZ modulation technique for upgrading optical wireless communication systems.

scholarly journals NOISE STABILITY OF SIGNAL RECEPTION ALGORITHMS WITH MULTIPULSE PULSE-POSITION MODULATION

2018 ◽  
Vol 42 (1) ◽  
pp. 167-174 ◽  
Author(s):  
V. I. Parfenov ◽  
D. Y. Golovanov
Keyword(s):  
Communication Systems ◽  
Pulse Sequence ◽  
Signal To Noise Ratio ◽  
Point Of View ◽  
Estimation Accuracy ◽  
Pulse Position Modulation ◽  
Signal To Noise ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Noise Ratio

An algorithm for estimating time positions and amplitudes of a periodic pulse sequence from a small number of samples was proposed. The number of these samples was determined only by the number of pulses. The performance of this algorithm was considered on the assumption that the spectrum of the original signal is limited with an ideal low-pass filter or the Nyquist filter, and conditions for the conversion from one filter to the other were determined. The efficiency of the proposed algorithm was investigated through analyzing in which way the dispersion of estimates of time positions and amplitudes depends on the signal-to-noise ratio and on the number of pulses in the sequence. It was shown that, from this point of view, the efficiency of the algorithm decreases with increasing number of sequence pulses. Besides, the efficiency of the proposed algorithm decreases with decreasing signal-to-noise ratio.It was found that, unlike the classical maximum likelihood algorithm, the proposed algorithm does not require a search for the maximum of a multivariable function, meanwhile characteristics of the estimates are practically the same for both these methods. Also, it was shown that the estimation accuracy of the proposed algorithm can be increased by an insignificant increase in the number of signal samples.The results obtained may be used in the practical design of laser communication systems, in which the multipulse pulse-position modulation is used for message transmission. 

scholarly journals Pattern Reconfigurable Antenna for VANET, Wi-Fi, and WiMAX Wireless Communication Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Rahmani Faouzi ◽  
Amar Touhami Naima ◽  
BelbachirKchairi Abdelmounaim ◽  
Aknin Noura ◽  
Taher Nihade
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Equivalent Circuit Model ◽  
Coaxial Cable ◽  
Wireless Communication Systems ◽  
Reconfigurable Antenna ◽  
Antenna Characteristic ◽  
Beam Switching ◽  
Theoretical Results ◽  
Good Agreement

This work presents the design and analysis of a beam switching antenna for VANET, Wi-Fi, and WiMAX wireless communication systems. The proposed reconfigurable antenna is powered by a coaxial cable and consists of a circular patch, six fish-shaped radiating elements, and a circular planar ground. The antenna was constructed on a Rogers RT5880 substrate. Its dimensions are as follows: 0.81λ0 × 0.81λ0 × 0.03λ0. It performs six reconfigurable operating states, at the same frequency, by controlling the activation and deactivation of six PIN diodes to change the beam’s direction. A theoretical equivalent circuit model of the antenna is extracted. A progressive analysis of improving the antenna characteristic performances is provided. The bandwidth of the proposed antenna is 9.07% (measured), 9.62% (simulated), and 9.31% (theoretical). The designed antenna has a maximum gain of 9.57 dB for all pattern states and a superior efficiency ratio from 85% to 95% over the operating range (5.54 GHz–6.10 GHz). The proposed reconfigurable antenna is fabricated. Measured, simulated, and theoretical results are given and show good agreement, including reflection coefficient (S11) and radiation patterns.

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