Publications
Low Complexity Subcarrier Activation Scheme for OFDM with Index Modulation
Dec 23, 2024Journal Radioelectronics and Communications Systems
Publisher Springer Nature
DOI 10.3103/S0735272724020018
Volume 67
Abstract: In orthogonal frequency division multiplexing with index modulation (OFDM-IM), data is mapped to subcarrier activation patterns (SAP) using look-up tables or combinatorial schemes. The complexity of these mapping schemes increases with the number of subcarriers. Therefore, they are applied to subgroups of subcarriers, but unfortunately, at the expense of reducing the amount of data loaded to an OFDM block. In this paper, low-complexity direct data to SAP mapping is proposed, the necessary analysis to determine the analytical bit error rate (BER) is presented, and the computer simulations are performed to find and compare theoretical and simulated BER results under conditions of the frequency selective Rayleigh fading channel. The proposed scheme can load more data bits to an OFDM block than conventional schemes. The results from computer simulations demonstrate the superiority of the OFDM-IM system using the proposed scheme over conventional OFDM-IM in terms of BER performance. © Allerton Press, Inc. 2024.
A Comprehensive Review of the Internet of Medical Things in Healthcare
Nov 1, 2024Journal nternational Journal of Electrical and Electronic Engineering and Telecommunications IJEETC
DOI doi: 10.18178/ijeetc.13.6.415-426
Issue 6
Volume 13
The continuous and rapid development in Internet of Medical Things (IoMT) technologies has led to the expansion of their applications in the field of healthcare and to increased interest in developing their technologies for the purpose of improving their performance in light of the challenges facing their practical application. This paper aims to provide a comprehensive up-to-date review of the literature on IoMT and telemedicine. The study discusses the growing interest in the Internet of Things (IoT) in healthcare, emphasizing the IoMT. It highlights the significance of the IoMT in intelligent healthcare systems, particularly in pandemics like COVID-19, where remote monitoring becomes crucial. This study examines the utilization of the IoMT systems, emphasizing on the application of sensors in healthcare industry. Furthermore, it highlights the significance of cloud computing, communication technologies, artificial intelligence, and Blockchain in IoMT. The challenges related to accepting IoMT in practice are explored; including data security, integration of protocols, data overload, accuracy and cost. Overall, the analyzed literature confirms that IoMT-based healthcare systems demonstrate significant potential in delivering comprehensive surveillance and immediate monitoring through public catastrophes. © 2024 by the authors. This is an open access article distributed under the Creative Commons Attribution License (CC BY-NC-ND 4.0), which permits use, distribution and reproduction in any medium, provided that the article is properly cited, the use is noncommercial and no modifications or adaptations are made.
A Review on Image Steganography
Jul 30, 2024Journal Lecture Notes in Networks and Systems
Publisher Springer Science and Business Media Deutschland GmbH
DOI 10.1007/978-981-97-3305-7_1
Volume 1004 LNNS
This paper is concerned with an important aspect of data security, known as steganography. In steganography, a secret message is hidden into another data file such as image, video, audio, or text file. The advantage of steganography over cryptography is that the intended secret message does not attract attention to itself as an object of scrutiny. In this paper, the different steganography techniques and related security issues are reviewed. The main focus is made on the most widely used technique called the Least Significant Bit (LSB) approach. The details of the LSB algorithm are presented, and it is implemented by using a MATLAB code. Text data has been embedded into a cover image, after the embedding process the stego image is generated that seems to be the same as the original cover image with only slight changes that Human Visual System cannot detect.
Enhancing Photovoltaic Array Performance under Partial Shading through Dynamic Reconfiguration and Layer Equalization Algorithm
Jul 1, 2024Journal https://ieeexplore.ieee.org/xpl/conhome/10569138/proceeding
Publisher IEEE
DOI https://doi.org/10.1109/ICCC62069.2024.10569654
Partial shading (PS) significantly impacts the performance of photovoltaic (PV) systems, leading to reduced efficiency. Traditional mitigation methods involve bypass diodes or PV module reconfiguration. Accordingly, the highest and lowest layer-based exchange (HLLBE) algorithm was proposed. The HLLBE system employs a Switching Block Array (SBA) for flexible reconfiguration without rewiring. By sorting and swapping irradiance readings, the HLLBE algorithm achieves uniform current distribution across PV array layers. Unlike static configurations, HLLBE dynamically adapts to shade patterns, offering an efficient solution. Simulations on a 3 × 3 PV array demonstrated HLLBE’s effectiveness in enhancing output power and reducing multiple peaks compared to conventional total-cross-tied (TCT) configurations. Additionally, HLLBE minimizes operating switches through a switching matrix during dynamic reconfiguration (DR). ©2024 IEEE.
A Scalable Hierarchical Dynamic PV Array Reconfiguration under Partial Shading
Dec 28, 2023Journal Energies
Publisher MDPI
DOI https://doi.org/10.3390/en17010181
Issue 1
Volume 17
Photovoltaic (PV) arrays are often affected by partial shading (PS), which can significantly reduce their power output. Dynamic reconfiguration is a promising technique for mitigating the negative effects of PS by adjusting the electrical connections of the PV modules in real-time. This paper introduces a hierarchical-based switching block scheme for the dynamic reconfiguration of PV arrays under PS conditions. With the aim of mitigating the negative impact of PS on PV arrays, the proposed system employs a low complexity and easily scalable architecture, making it well-suited for practical applications. Comparative assessments against conventional configurations such as bridge-linked (BL), total-cross-tied (TCT), and series–parallel (SP) reveal superior energy harvesting efficiency for the proposed system under various shading conditions. The hierarchical switching block architecture, featuring multiple levels of switching blocks, enables efficient and flexible reconfiguration of the PV array, even in the presence of complex shading patterns. Through extensive simulations, the system consistently outperforms conventional configurations by adapting effectively to changing shading patterns and optimizing the PV array’s output. The proposed switching block (SB) reconfiguration technique significantly outperforms existing methods like TCT, Sudoku, dynamic proposals, and Magic Square in terms of both power generation (up to 42.52% increase) and efficiency (up to 42.13% improvement) under diverse partial shading conditions. The proposed hierarchical-based switching block scheme thus presents a promising solution for enhancing the dynamic reconfiguration of PV arrays under PS conditions, offering a balance between low complexity, scalability, and superior energy harvesting efficiency for practical applications in the realm of solar energy. © 2023 by the authors.
Dynamic Reconfiguration of PV Array under Partial Shading Condition by Using Automatic Switching
Jul 1, 2023Journal IJEETC
DOI 10.18178/ijeetc.12.4.272-278
Issue 4
Volume 12
The mismatching effect caused by partial shade is one of the critical problems in the operation of photovoltaic (PV) arrays, it can cause large losses in the power produced by the PV system. Power losses due to Partial Shading (PS) for a particular operating situation may be controlled by altering the PV array's scheme connection. For that reason, this paper presents an Automatic Switch Block (ASB) based on dynamic relays without using an algorithm to control the connection between PV panels to reduce the effect of partial shading and provide the ability of scaling. The Simulation results showed that the proposed module has a high ability and efficiency in mitigating and reducing the effect of partial shade on solar panel arrays by automatically changing the electrical connection between the panels compared with Total Cross-Tied (TCT), Futoshiki Puzzle Pattern (FPP), Sudoku and L-Shape Algorithm. Moreover, the proposed method was tested in SIMULINK/MATLAB environment for different shading patterns and achieved an improvement in Maximum Power Point Tracking (MPPT) by about 12% as compared with L-Shape, more than 30% compared to TCT, and about 15% for other methods. © 2023 by the authors. This is an open access article distributed under the Creative Commons Attribution License (CC BYNC-ND 4.0), which permits use, distribution and reproduction in any medium, provided that the article is properly cited, the use is noncommercial and no modifications or adaptations are made.
Peak to Average Power Ratio Reduction for OFDM with IM System
Mar 27, 2023Journal https://ieeexplore.ieee.org/xpl/conhome/10075549/proceeding
Publisher IEEE
DOI https://doi.org/10.1109/ICOASE56293.2022.10075595
This paper is interested in studying the Peak to Average Power Ratio (PAPR) reduction in Orthogonal Frequency Division Multiplexing with Index Modulation (OFDM-IM) system transmitter. PAPR is a common issue in multicarrier transmission techniques which is the result of adding independent multicarrier signals of different peak values on the same phases. The reduction schemes have been diversly examined for classical OFDM and the majority of them can be directly extended to OFDM-IM while some require slight changes to suit the OFDM-IM characteristics. Selective Mapping (SLM), Partial Transmit Sequence (PTS), Tone Reservation (TR), and Peak Insertion (PI) are some examples on the reduction schemes that will be investigated throughout this paper. As for PI, to the best knowledge of the authors is for the first time implemented in OFDM-IM. The system parameters effects, number of total subcarriers(N), number of subblocks (n), the active subcarriers (k), and the activation ratio (r) are studied to gain the lowest PAPR amount possible that reached (1.2 dB) at specified system parameters. © 2022 IEEE.
An economic tracking scheme for GPS-gsm based moving object tracking system
May 30, 2019Journal https://ieeexplore.ieee.org/xpl/conhome/8716485/proceeding
Publisher IEEE
DOI https://doi.org/10.1109/ICETS.2018.8724614
Many tracking systems are based on the Global Positioning System (GPS), Global System for Mobile communications (GSM) and smart phones, due to their wide availability and reliability. A moving object to be tracked, it sends its GPS coordinates to the observer via SMS. However, the economic feasibility of these systems mainly depends on the total cost of the used SMS messages. In this paper, an economic tracking scheme is proposed to reduce the tracking cost. A GPS-GSM tracking system that uses the proposed scheme is implemented and tested together with two classical tracking systems under two practical test cases. The first test case is a 121 km vehicle trip and the second is a 2.4 km walking journey. The results showed the effectiveness and economic feasibility of the proposed system, which achieved a saving in tracking cost up to about 64% with respect to the tested classical systems. © 2018 IEEE.
Effect of Subcarrier Activation Ratio on the Performance of OFDM-IM over Rayleigh Fading Channel
Jun 1, 2017Journal IEEE Communications Letters
Publisher IEEE
DOI https://doi.org/10.1109/LCOMM.2017.2668410
Issue 6
Volume 21
Orthogonal frequency division multiplexing with index modulation (OFDM-IM) is acquiring increasing attention due to its advantages over classical OFDM. These advantages include superior BER performance and transmit power saving since only a subset of the subcarriers is activated to transmit M-QAM symbols and the remaining subcarriers are turned OFF. The vast majority of the literature studies the OFDM-IM by assuming certain subcarrier activation ratios, r, together with other system parameters without figuring out the possible variation in system performance at other r values. In this letter, the effect of r and M on the spectral efficiency (SE) and BER of OFDM-IM is investigated. An inequality is developed to maximize SE while power saving is maintained. Moreover, the BER performance of an OFDM-IM system exploiting a maximum subcarrier energy detector over multipath Rayleigh channel is analyzed. An approximate average BER expression is derived and the effect of r and M is discussed. Computer simulation has showed the validity of the derived expressions. © 1997-2012 IEEE.
Low Complexity OFDM-IM Detector by Encoding All Possible Subcarrier Activation Patterns
Mar 1, 2016Journal IEEE Communications Letters
Publisher IEEE
DOI https://doi.org/10.1109/LCOMM.2015.2514278
Issue 3
Volume 20
In orthogonal frequency division multiplexing with index modulation (OFDM-IM), the use of a maximum likelihood (ML) detector becomes impractical for large number of subcarriers per subblock, due to its exponentially growing detection complexity. Lower complexity detectors determine the received subcarrier activation pattern (SAP) through detecting the state of the subcarriers by thresholding. These detectors suffer from errors due to the possibility of detecting an invalid SAP since not all of the possible SAPs are used in OFDM-IM. In this letter, it is proposed to exploit all of the possible SAPs to convey data to neglect the possibility of detecting invalid SAPs. The proposed scheme together with a low complexity SAP detector results in a low-complexity (LC)-OFDM-IM. An approximate analytical expression is derived for the BER of the proposed LC-OFDM-IM system. Simulation of the LC-OFDM-IM and an OFDM-IM with a ML detector show that they are almost equivalent in terms of BER performance. The results and the features of the LC-OFDM-IM suggest it as a candidate alternative to conventional OFDM-IM. © 2015 IEEE.
PAPR reduction in OFDM systems using peak insertion
Feb 1, 2015Journal AEU - International Journal of Electronics and Communications
Publisher ELSEVIER
DOI https://doi.org/10.1016/j.aeue.2014.11.009
Issue 2
Volume 69
A technique for Peak-to-Average Power Ratio (PAPR) reduction of Orthogonal Frequency Division Multiplexing (OFDM) signals by Peak Insertion (PI) is proposed in this paper. PI depends on the duality property of the DFT and PAPR duality of an impulse. A relatively high peak is inserted to the OFDM symbol in the frequency domain such that the PAPR of the transmitted time domain signal is reduced. PAPR reduction up to about 11 dB at PAPR CCDF of 10-4 is achievable by PI, but at the expense of increased signal power, which can be reduced by scaling to the desired level without affecting its PAPR. Computer simulation tests show that a tradeoff can easily be made between BER and the PAPR of the transmitted signal to achieve a desired system performance. The PI technique does not require any sort of side information transmission, searching, optimization, and iterative or parallel application of IDFT. PI is faster, simpler, and capable of achieving greater PAPR reduction as compared with other similar techniques which result in transmitted power increase, and therefore, it seems to be suitable to be used for OFDM signal PAPR reduction. © 2014 Elsevier GmbH.