scholarly journals PAPR REDUCTION TECHNIQUES AND IMAGE QUALITY ASSESSMENTIN IMAGE BASED MMS VLC SYSTEM

2021 ◽  
Vol 9 (2) ◽  
pp. 1178-1185
Author(s):  
Kiranmai Babburu , Et. al.

The radiofrequency method of transmission suffers from the problem of the limited licensed radio frequency spectrum, & security, wide EMI (electromagnetic interference), high multipath fading & power consumption for short-range applications. The solution to these problems can be achieved by using optical wireless communication technique called the Visible Light Communication system where the data is sent through regulated emission of light. The transmission of digital image information productively in the present optical wireless communication framework is an uphill task as these systems often suffer from problems like frequency selective fading propagation losses and inter-symbol interferences. In order to conquer such difficulties we hereby propose a robust method to transfer the digital image through a Multi-Carrier Modulation Scheme-MMS. In this paper, an Image-Based Multicarrier modulation VLC system is designed through which is sent a corrupted Digital Image with additive white Gaussian noise and explored the overall execution of the Image based Multicarrier modulation VLC system at distinct SNR values.  The paper also addresses the issue of high Peak to Average Power Ratio (PAPR) in Multicarrier modulation and reduced it by using different PAPR reduction techniques. The received image quality of the proposed system is obtained under different signal to noise ratios at different modulation schemes..

Author(s):  
Salima Senhadji ◽  
Yassine Mohammed Bendimerad ◽  
Fathi Tarik Bendimerad

<span>One of the major problems that faces any wireless communication system that apply multicarrier modulation technology is large Peak-to-Average Power Ratio (PAPR). There are divers PAPR reduction methods to solve this problem. Tone Reservation (TR) scheme is one of the most famous PAPR reduction techniques in which a peak cancelling signal is added to the original one in such a way that PAPR will reduce. Companding is another easy PAPR reduction technique in which compression of large amplitude samples and expansion of low one. In this paper, we suggest a new PAPR reduction scheme based on combining tone reservation and companding techniques for FBMC-OQAM systems. The simulation results show that the new scheme (TR&amp;Compd) presents better result in term of PAPR reduction compared to TR and Companding methods taken separately.</span>


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Zsolt Kollár ◽  
Lajos Varga ◽  
Bálint Horváth ◽  
Péter Bakki ◽  
János Bitó

This paper investigates filter bankmulticarrier (FBMC), a multicarrier modulation technique exhibiting an extremely low adjacent channel leakage ratio (ACLR) compared to conventional orthogonal frequency division multiplexing (OFDM) technique. The low ACLR of the transmitted FBMC signal makes it especially favorable in cognitive radio applications, where strict requirements are posed on out-of-band radiation. Large dynamic range resulting in high peak-to-average power ratio (PAPR) is characteristic of all sorts of multicarrier signals. The advantageous spectral properties of the high-PAPR FBMC signal are significantly degraded if nonlinearities are present in the transceiver chain. Spectral regrowth may appear, causing harmful interference in the neighboring frequency bands. This paper presents novel clipping based PAPR reduction techniques, evaluated and compared by simulations and measurements, with an emphasis on spectral aspects. The paper gives an overall comparison of PAPR reduction techniques, focusing on the reduction of the dynamic range of FBMC signals without increasing out-of-band radiation. An overview is presented on transmitter oriented techniques employing baseband clipping, which can maintain the system performance with a desired bit error rate (BER).


Author(s):  
Rajbir Singh

Optical networks are bandwidth efficient networks are used for long haul communication providing seamless data transfer. For high speed data transmission in open space between different satellites, Inter-satellite Optical wireless communication (IsOWC) is widely used .In this paper we have evaluated the performance of IsOWC communication link for high speed data transmission .The performance of the system is evaluated on the basis of qualitative parameters such as Q-factor and BER using optisystem simulator.


Author(s):  
SHARMA POOJA ◽  
SHRIVASTAVA SHARAD MOHAN ◽  
MISHRA ANUJA ◽  
AGRAWAL PRACHI ◽  
PARGANIHA RAHUL ◽  
...  

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 632
Author(s):  
Xiaozheng Wang ◽  
Minglun Zhang ◽  
Hongyu Zhou ◽  
Xiaomin Ren

The performance of the underwater optical wireless communication (UOWC) system is highly affected by seawater´s inherent optical properties and the solar radiation from sunlight, especially for a shallow environment. The multipath effect and degradations in signal-to-noise ratio (SNR) due to absorption, scattering, and ambient noises can significantly limit the viable communication range, which poses key challenges to its large-scale commercial applications. To this end, this paper proposes a unified model for underwater channel characterization and system performance analysis in the presence of solar noises utilizing a photon tracing algorithm. Besides, we developed a generic simulation platform with configurable parameters and self-defined scenarios via MATLAB. Based on this platform, a comprehensive investigation of underwater channel impairments was conducted including temporal and spatial dispersion, illumination distribution pattern, and statistical attenuation with various oceanic types. The impact of ambient noise at different operation depths on the bit error rate (BER) performance of the shallow UOWC system was evaluated under typical specifications. Simulation results revealed that the multipath dispersion is tied closely to the multiple scattering phenomenon. The delay spread and ambient noise effect can be mitigated by considering a narrow field of view (FOV) and it also enables the system to exhibit optimal performance on combining with a wide aperture.


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