Institute of Electron Technology
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2189 research outputs found
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A Scalable Multicast Routing Protocol for Mobile Ad-Hoc Networks, Journal of Telecommunications and Information Technology, 2022, nr 2
Full text linkThe multicasting technique supports a variety of applications that require data to be instantaneously transmitted to a set of destination nodes. In environments with continuously moving nodes, such as mobile ad-hoc networks, the search for efficient routes from sources to the projected destinations is a common issue. Proposed Windmill protocol provides a scalable multicast solution for mobile ad-hoc networks. Windmill aims to improve routing protocol’s performance by introducing a hierarchal distributed routing algorithm and dividing the area into zones. Additionally, it attempts to demonstrate better scalability, performance and robustness when faced with frequent topology changes, by utilizing restricted directional flooding. A detailed and extensive simulated performance evaluation has been conducted to assess Windmill and compare it with multicast ad-hoc on-demand distance vector (MAODV) and on-demand multicast routing protocols (ODMRP). Simulation results show that the three protocols achieved high packet delivery rates in most scenarios. Results also show that Windmill is capable of achieving scalability by maintaining the minimum packet routing load, even upon increasing the nodes’ speed, the number of sources, the number of group members and the size of the simulated network. The results also indicate that it offers superior performance and is well suited for ad-hoc wireless networks with mobile hosts. The trade-off of using Windmill consists in slightly longer paths – a characteristic that makes it a good choice for applications that require simultaneous data transmission to a large set of nodes
Design of a Modified Interleaving Algorithm Based on Golden Section Theory Enhancing the Performance of Turbo Codes, Journal of Telecommunications and Information Technology, 2022, nr 2
Full text linkThis paper investigates the design of a modified matrix interleaving algorithm as a way to improve the performance of turbo codes. This proposed solution, known as the matrix-dithered golden (MDG) interleaver, utilizes the characteristics of a matrix interleaver combined with the golden section theory. The performance of the proposed interleaving method is compared with that of matrix (M), random (R), and dithered golden (DG) interleavers. The comparison is made in terms of bit error rate (BER), frame error rate (FER), computational complexity, and storage memory requirement. The turbo coded system is implemented and simulated using Matlab/Simulink software. Results of simulations performed both in the additive white Gaussian noise (AWGN) channel and the Rayleigh fading channel demonstrate the effectiveness of the proposed interleaver. The MDG interleaver is an effective replacement for random interleavers, as it improves BER and FER performance of the turbo code and is also capable of reducing the storage memory requirement without increasing the system’s complexity
Semantic Knowledge Management and Blockchain-based Privacy for Internet of Things Applications, Journal of Telecommunications and Information Technology, 2022, nr 3
Full text linkDesign of distributed complex systems raises several important challenges, such as: confidentiality, data authentication and integrity, semantic contextual knowledge sharing, as well as common and intelligible understanding of the environment. Among the many challenges are semantic heterogeneity that occurs during dynamic knowledge extraction and authorization decisions which need to be taken when a resource is Accessem in an open, dynamic environment. Blockchain offers the tools to protect sensitive personal data and solve reliability issues by providing a secure communication architecture. However, setting-up blockchain-based applications comes with many challenges, including processing and fusing heterogeneous information from various sources. The ontology model explored in this paper relies on a unified knowledge representation method and thus is the backbone of a distributed system aiming to tackle semantic heterogeneity and to model decentralized management of Access control authorizations.We intertwine the blockchain technology with an ontological model to enhance knowledge management processes for distributed systems. Therefore, rather than reling on the mediation of a third party, the approach enhances autonomous decision-making. The proposed approach collects data generated by sensors into higher-level abstraction using n-ary hierarchical structures to describe entities and actions. Moreover, the proposed semantic architecture relies on hyperledger fabric to ensure the checking and authentication of knowledge integrity while preserving privacy
Chaotic-based Orthogonal Frequency Division Multiplexing with Index Modulation, Journal of Telecommunications and Information Technology, 2022, nr 4
Full text linkOrthogonal frequency division multiplexing with index modulation (OFDM-IM), stands out among conventional communication technologies, as it uses the indices of the available transmit entities. Thanks to such an approach, it offers a novel method for the transmission of extra data bits. Recent years have seen a great interest in chaos-based communications. The spectrum-spreading signals used in chaotic signal modulation technologies are orthogonal to the existing mixed signals. This paper presents how well a non-coherent differential chaos shift keying communication system performs across an AWGN. Different types of detection methods are simulated, bit error rate and power spectral density are calculated and then compared with standard OFDM with index modulation. The results of simulations concerning the performance of a DCSK system, adding to the security of the proposed solution and offering a comparable bit error rate performance, are presented in the paper as well
RED-LE: A Revised Algorithm for Active Queue Management, Journal of Telecommunications and Information Technology, 2022, nr 2
Full text linkThe random early detection (RED) algorithm was developed in 1993. Nearly three decades later, several improved variants have been proposed by scientists. The use of a (pure) linear function for computing packet drop probability has turned out to be a disadvantage, leading to the problem of large delays. Such a problem may be addressed by using linear and non-linear (i.e. as exponential) packet drop probability functions. This paper proposes a revised RED active queue management algorithm named RED-linear exponential (RED-LE). This variant involves an interplay of linear and exponential drop functions, in order to improve the performance of the original RED algorithm. More importantly, at low and moderate network traffic loads, the RED-LE algorithm employs the linear drop action. However, for high traffic loads, RED-LE employs the exponential function for computing the packet drop probability rate. Experimental results have shown that RED-LE effectively controls congestion and offers an improved network performance under different traffic loads
An Approximate Evaluation of BER Performance for Downlink GSVD-NOMA with Joint Maximum-likelihood Detector, Journal of Telecommunications and Information Technology, 2022, nr 3
Full text linkGeneralized Singular Value Decomposition (GSVD) is the enabling linear precoding scheme for multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) systems. In this paper, we extend research concerning downlink MIMO-NOMA systems with GSVD to cover bit terror rate (BER) performance and to derive an approximate evaluation of the average BER performance. Specifically, we deploy, AT the base station, the well-known technique of joint-modulation to generate NOMAsymbols and joint maximum-likelihood (ML) to recover the transmitted data at end user locations. Consequently, the joint ML detector offers almost the same performance, In terms of average BER as ideal successive interference cancellation. Next, we also investigate BER performance of other precoding schemes, such as zero-forcing, block diagonalization, and simultaneous triangularization, comparing them with GSVD. Furthermore, BER performance is verified in different configurations in relation to the number of antennas. In cases where the number of transmit antennas is greater than twice the number of receive antennas, average BER performance is superior
Modeling of Microwave Cavities Based on SIBC-FDTD Method for EM Wave Focalization by TR Technique, Journal of Telecommunications and Information Technology, 2022, nr 3
Full text linkThe time reversal (TR) techniques used in electromagnetics have been limited for a variety of reasons, including extensive computations, complex modeling and simulation, processes as well as, large-scale numerical analysis. In this paper, the SIBC-FDTD method is applied to address these issues and to efficiently model TR systems. An original curvilinear modeling method is also proposed for constructing various obstacles in a 2D microwave cavity and for processing the corners of the cavity. The EM waves’ spatio-temporal focalization has been realized, and results of the simulations further prove the accuracy and effectiveness of this modeling method. Furthermore, they demonstrate that the microwave cavity processes may significantly improve the focalization quality in terms of SSLL enhancement
Enhancing Moon Crescent Visibility Using Contrast-Limited Adaptive Histogram Equalization and Bilateral Filtering Techniques, Journal of Telecommunications and Information Technology, 2022, nr 1,
Full text linkImage enhancement is becoming increasingly im portant with the advancement of space exploration techniques and the technological development of more durable and sci entifically sound observatories equipped with more powerful telescopes. The enhancement of images helps astronomers an alyze the results and act toward determining the dates of religious festivals. This work describes a technique known as contrast-limited adaptive histogram equalization (CLAHE) with grayscale contrast enhancement and bilateral filtering. We apply CLAHE on the L component of the CIE-Lab color space to adjust lightness contrast. Subsequently, grayscale contrast enhancement is performed to increase the visibility of the moon crescent. Noise caused by grayscale contrast en hancement is reduced using bilateral filtering. Two quantita tive measures are selected (PSNR and MSE) to show the visual improvement achieved by the proposed algorithm