In this paper, the different detection techniques are investigated- Direct Detection and Coherent Heterodyne Detection on FMCW LiDAR system using Optisystem package. The results of investigations ...done are included to see the influence of laser physical parameters- Active Length, Active Layer Width and Reflectivity on LiDAR performance parameters- Power Received, SNR at photodetector output and beam parameters- Beam Diameter and Beam Divergence. This investigation is done using DFB laser and FP laser in place of CW laser in different reference models for different detection techniques. The optimised values of laser physical parameters are obtained where the DFB Laser and FP Laser provide the same performance as that of the CW Laser.
Broadband power line is an important way of communication in low-voltage distribution networks because a power line is everywhere nowadays. However, due to the heterogeneity of a practical power-line ...network and various loads connected to its termination points, modelling and simulation of power-line communication (PLC) channels are difficult and complicated issues. In this work, the authors propose a novel PLC channel modelling approach using graph theory for the first time when knowing the power-line network topologies and cable distributed parameters. The approach utilises simple and effective recursive operations in solving the k-shortest paths to estimate the channel transfer function for a specific power-line network, it overcomes the complicated analytical derivation in computing the channel transfer function by the traditional two-port network in the bottom-up model and avoids to measure the actual channel in a top-down model. Their proposed approach is validated by transmission-line (TL) theory as well as measurement results, and it is also compared with TL theory. The results show that their proposed PLC channel modelling approach herein is simple to be implemented, it is expected to have extensive applications in broadband PLC systems for performance evaluations.
Using DNA as the medium to store information has recently been recognized as a promising solution for long-term data storage. While several system prototypes have been demonstrated, the error ...characteristics in DNA data storage are discussed with limited content. Due to the data and process variations from experiment to experiment, the error variation and its effect on data recovery remain to be uncovered. To close the gap, we systematically investigate the storage channel, i.e., error characteristics in the storage process. In this work, we first propose a new concept named sequence corruption to unify the error characteristics into the sequence level, easing the channel analysis. Then we derived the formulations of the data imperfection at the decoder including both sequence loss and sequence corruption, revealing the decoding demand and monitoring the data recovery. Furthermore, we extensively explored several data-dependent unevenness observed in the base error patterns and studied a few potential factors and their impacts on the data imperfection at the decoder both theoretically and experimentally. The results presented here introduce a more comprehensive channel model and offer a new angle towards the data recovery issue in DNA data storage by further elucidating the error characteristics of the storage process.
The paper presents an analytical model of the terahertz (THz) communication channel (0.1 - 10 THz) for in-vivo nano-networks by considering the effect of noise on link quality and information rate. ...The molecular absorption noise model for in-vivo nano-networks is developed based on the physical mechanisms of the noise present in the medium, which takes into account both the radiation of the medium and the molecular absorption from the transmitted signal. The signal-to-noise ratio (SNR) of the communication channel is investigated for different power allocation schemes and the maximum achievable information rate is studied to explore the potential of THz communication inside the human body. The obtained results show that the information rate is inversely proportional to the transmission distance. Based on the studies on channel performance, it can be concluded that the achievable transmission distance of in-vivo THz nano-networks should be restrained to approximately 2 mm maximum, while the operation band of in-vivo THz nano-networks should be limited to the lower band of the THz band. This motivates the utilisation of hierarchical/cooperative networking concepts and hybrid communication techniques using molecular and electromagnetic methods for future body-centric nano-networks.
This paper addresses the use of machine learning techniques for the determination of subgroups within 5G networks. Currently, the burden of determining the subgroups falls uniquely on the gNB. The ...aim of this work is to lighten the computation burden of the gNB in estimating the evaluation of the position and mobility of users, with the ultimate aim of determining the optimal modulation and coding scheme (MCS). This work proposes an innovative approach based on machine learning techniques that are interposed among user and gNB, helping the latter to determine the network configuration. The results obtained show how direct communication between UEs and neural network speeds up the determination of the MCS and the allocation of resources to subgroups within 5G technology.
Abstract In the present era of technology, it is quite fascinating to design a system capable of transmitting information from one end to another by using the optical spectrum. This system differs ...from optical fibre communication in terms of channel medium. Optical fibre technology uses the end-to-end physical connection via fibre. In contrast, Light-based wireless communication networks, also known as wireless optical communication (WOC) networks or fibreless optical communication networks, use light as a carrier and air as an unguided propagation media for transmission. Fibreless optical communication eliminates the need for Licensing and Buried Fibre Cables; also, its installation is relatively easy. This survey article describes the evolution of WOC technologies right from the old methods of communication to today’s deep-space optical satellite communication. This article briefly describes the WOC system working principle, categorization of wireless optical systems (based on the carrier frequency wavelength, distance covered, and application), different modulation techniques adopted for wireless optical communication, challenges associated with channel medium and channel modelling, performance analysis of WOC system, various application areas of WOC network, commercial developments in the field of WOC, and some other emerging trends associated with WOC.
In this letter, we propose new channel characterizations for <xref rid="deqn1" ref-type="disp-formula">(1) stochastic Terahertz (THz) communications and <xref rid="deqn2" ref-type="disp-formula">(2) ...reconfigurable intelligent surface (RIS)-aided THz systems. Considering a spherical network with stochastic distances between nodes, we derive the exact closed-form expressions for the probability density function (PDF) and the cumulative distribution function (CDF) of the signal-to-noise ratio (SNR) over the direct link. Using the method of moments, the cascaded channels can be precisely characterized by <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">\mu </tex-math></inline-formula> distribution. We show that by using a massive number of reflecting elements, <inline-formula> <tex-math notation="LaTeX">{M} </tex-math></inline-formula>, (e.g., <inline-formula> <tex-math notation="LaTeX">{M}~\geq </tex-math></inline-formula> 4096) the cascaded link actually outperforms the direct THz link in terms of outage probability (OP).
Personal communication methods in underground coal mines are far less sophisticated and efficient than surface level communication techniques. This deficiency can be attributed to the generally ...unfavourable and hazardous environment prevailing underground which acts as a deterring factor for their development. However, effective and reliable communication between underground coal mines and the control room on the surface is essential for safety and emergency rescue operations. Wireless communication is not a viable alternative because of the high attenuation profile as well as variation in the propagation path through uneven structures of underground coal mines and inflammable gases and moisture generally present there. Hence, wired personal communications using an existing structure such as power lines forms a very efficient and economical approach. This paper investigates the developments of communication in underground coal mines in India and presents an overview of the power line communication (PLC) technology. The possible use of PLC especially for deployment in underground coal mines in India is discussed in detail.
Geometrical-based stochastic channel modelling approach of the wireless propagation radio links remained the topic of interest in the researcher community over the last few decades. Researchers and ...theorists have examined and verified through measurements the impact of various parameters of the channel on the correlations between the array elements of multiple-input and multiple-output (MIMO) antenna for different wireless propagation scenarios. In the previously proposed elliptical-based scattering channel model , mobile stations (MSs) are assumed to be fixed at the centre of elliptical geometry that resembles the situation when fast-moving calling subscribers to reside in streets, canyons or on the highways, where the scattering objects like vegetation, high-rise structures and safety walls are present at roadside terrain. In this paper, the elliptical-scattering channel model is analysed for power density spectrum (PDS) when any of the MSs moves with some velocity in any direction. Moreover, the derived theoretical results are plotted for various channel parameters like relative velocities of the MSs, and normalized frequency used. Finally, the result of the PDS of the proposed M2M elliptical scattering model is compared with the results of the F2M channel model.
PDF
