SummaryIn this paper, we propose two downlink multiple access architectures for networks where human‐type communication users (HTCUs) and machine‐type communication devices (MTCDs) coexist. The proposed schemes combine non‐orthogonal multiple access (NOMA), orthogonal frequency division multiplexing (OFDM), and index modulation (OFDM‐IM) concepts. In the first scheme, the base station (BS) transmits bits of HTCUs using modulated symbols and bits of MTCDs by the subcarrier activation pattern (SAP). This approach called IM‐NOMA with null subcarriers (IM‐NOMA‐NS) ensures that inactive subcarriers are always null, which improves the system bit error rate (BER) performance. To improve the spectral efficiency (SE), we propose a second approach, termed IM‐NOMA with dual‐mode modulation (IM‐NOMA‐DM), in which the HTCUs' bits are transmitted using two‐dimensional modulation and the MTCDs' bits are transmitted using one‐dimensional modulation and the SAP. For each proposed system, a near‐optimal low‐complexity detector, based on the energy‐detection (ED) and the log‐likelihood ratio (LLR) criterion, is provided to mitigate the detection burden of the optimal maximum‐likelihood (ML) detector. The BER performances and SE of the proposed schemes are investigated. The average BERs of IM‐NOMA‐NS and IM‐NOMA‐DM are derived in closed‐form expressions corroborated by the simulation results. We have proved numerically that the proposed schemes achieve a good trade‐off between BER performance, SE, and the number of supported users, making them more suitable for Internet of Things (IoT) applications.
摘要本文为人类型通信用户（HTCU）和机器型通信设备（MTCD）共存的网络提出了两种下行链路多路接入架构。所提方案结合了非正交多址接入（NOMA）、正交频分复用（OFDM）和索引调制（OFDM-IM）概念。在第一种方案中，基站（BS）通过调制符号传输 HTCU 的比特，通过子载波激活模式（SAP）传输 MTCD 的比特。这种方法被称为空子载波 IM-NOMA（IM-NOMA-NS），可确保非激活子载波始终为空，从而提高系统误码率（BER）性能。为了提高频谱效率（SE），我们提出了第二种方法，即双模调制 IM-NOMA（IM-NOMA-DM），其中 HTCU 比特使用二维调制传输，MTCD 比特使用一维调制和 SAP 传输。根据能量检测（ED）和对数似然比（LLR）准则，为每个拟议系统提供了近乎最佳的低复杂度检测器，以减轻最佳最大似然（ML）检测器的检测负担。对所提方案的误码率性能和 SE 进行了研究。IM-NOMA-NS 和 IM-NOMA-DM 的平均误码率以闭合形式表达，并得到了仿真结果的证实。我们通过数值证明，所提出的方案在误码率性能、SE 和支持的用户数量之间实现了良好的权衡，因此更适合物联网 (IoT) 应用。
{"title":"A new subcarrier‐index modulation schemes for downlink NOMA systems","authors":"Issa Chihaoui, Mohamed Lassaad Ammari","doi":"10.1002/dac.5919","DOIUrl":"https://doi.org/10.1002/dac.5919","url":null,"abstract":"SummaryIn this paper, we propose two downlink multiple access architectures for networks where human‐type communication users (HTCUs) and machine‐type communication devices (MTCDs) coexist. The proposed schemes combine non‐orthogonal multiple access (NOMA), orthogonal frequency division multiplexing (OFDM), and index modulation (OFDM‐IM) concepts. In the first scheme, the base station (BS) transmits bits of HTCUs using modulated symbols and bits of MTCDs by the subcarrier activation pattern (SAP). This approach called IM‐NOMA with null subcarriers (IM‐NOMA‐NS) ensures that inactive subcarriers are always null, which improves the system bit error rate (BER) performance. To improve the spectral efficiency (SE), we propose a second approach, termed IM‐NOMA with dual‐mode modulation (IM‐NOMA‐DM), in which the HTCUs' bits are transmitted using two‐dimensional modulation and the MTCDs' bits are transmitted using one‐dimensional modulation and the SAP. For each proposed system, a near‐optimal low‐complexity detector, based on the energy‐detection (ED) and the log‐likelihood ratio (LLR) criterion, is provided to mitigate the detection burden of the optimal maximum‐likelihood (ML) detector. The BER performances and SE of the proposed schemes are investigated. The average BERs of IM‐NOMA‐NS and IM‐NOMA‐DM are derived in closed‐form expressions corroborated by the simulation results. We have proved numerically that the proposed schemes achieve a good trade‐off between BER performance, SE, and the number of supported users, making them more suitable for Internet of Things (IoT) applications.","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141737928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SummaryA low profile, concave conformal ring cylindrical dielectric resonator antenna (CDRA) employing frequency selective surface (FSS) using split ring resonator (SRR) for wideband and high gain applications is presented. The ring CDRA loaded with the monopole is designed to excite the TM01δ mode to increase the antenna's bandwidth. The effect of a curved ground plane (GP) on the radiation performance of CDRA is studied. A 5 × 5 array of the SRR is placed above the conformal GP at a far‐field distance optimized to (2n ± 1) λ/4 from the radiating element to enhance the gain of the proposed structure. The planar CDRA with FSS is compared with the conformal CDRA with FSS and a 4.3 GHz improvement in bandwidth is observed due to the multiple reflection and surface reflection leading to a 3.2 dBi improvement in gain. An impedance bandwidth of 51.8% (5 to 8.5 GHz) with a maximum gain of 8.7 dBi at 7.3 GHz resonant frequency and 99% radiation efficiency at 5.9 GHz is offered by the proposed antenna with FSS. Additionally, the proposed CDRA has a low profile of 0.12 λ0 where λ0 is the lower cut‐off frequency's wavelength. A good agreement is observed between the simulated and measured results.
{"title":"A low profile high gain concave conformal ring cylindrical dielectric resonator antenna loaded with split ring resonator for ISM and C band applications","authors":"Manshree Mishra, Anil Rajput, Garima Tiwari, Pramod Kumar Gupta, Biswajeet Mukherjee","doi":"10.1002/dac.5921","DOIUrl":"https://doi.org/10.1002/dac.5921","url":null,"abstract":"SummaryA low profile, concave conformal ring cylindrical dielectric resonator antenna (CDRA) employing frequency selective surface (FSS) using split ring resonator (SRR) for wideband and high gain applications is presented. The ring CDRA loaded with the monopole is designed to excite the TM<jats:sub>01δ</jats:sub> mode to increase the antenna's bandwidth. The effect of a curved ground plane (GP) on the radiation performance of CDRA is studied. A 5 × 5 array of the SRR is placed above the conformal GP at a far‐field distance optimized to (2n ± 1) λ/4 from the radiating element to enhance the gain of the proposed structure. The planar CDRA with FSS is compared with the conformal CDRA with FSS and a 4.3 GHz improvement in bandwidth is observed due to the multiple reflection and surface reflection leading to a 3.2 dBi improvement in gain. An impedance bandwidth of 51.8% (5 to 8.5 GHz) with a maximum gain of 8.7 dBi at 7.3 GHz resonant frequency and 99% radiation efficiency at 5.9 GHz is offered by the proposed antenna with FSS. Additionally, the proposed CDRA has a low profile of 0.12 λ<jats:sub>0</jats:sub> where λ<jats:sub>0</jats:sub> is the lower cut‐off frequency's wavelength. A good agreement is observed between the simulated and measured results.","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141737929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SummaryMassive multiple‐input multiple‐output (MA‐MIMO) has been hailed as an auspicious technology for the future generation of wireless communications because it can considerably increase the capacity of the communication network. However, using the maximum likelihood (ML) direction‐of‐arrival (DOA) estimate method is severely constrained in actual systems because of the computationally expensive multi‐dimensional searching procedure. This paper proposes a novel approach to estimate DOA and channels by incorporating deep learning into the MA‐MIMO system. Here, a deep belief network (DBN) is used to learn both the spatial structures in the angle domain and the statistics of the wireless channel through both online and offline learning procedures. Also, a bald eagle search (BES) Optimization is used along with DBN to attain high precision through optimal training. The proposed model can estimate the channel based on the predicted DOA and the complex gain. According to numerical results, the suggested method performs significantly better than state‐of‐the‐art methods, particularly in tough conditions like low signal‐to‐noise ratio (SNR) and a finite number of snapshots. The proposed DBN‐BES technique accomplishes less root mean square error (RMSE) as 0.01 for SNR of 5 dB in elevation calculation and 0.02 for SNR of 5 dB in azimuth calculation. Also, the proposed algorithm greatly reduces computational complexity.
摘要大规模多输入多输出（MA-MIMO）被誉为新一代无线通信的吉祥技术，因为它能大大提高通信网络的容量。然而，在实际系统中，使用最大似然（ML）到达方向（DOA）估计方法受到严重限制，因为多维搜索过程的计算成本很高。本文提出了一种通过将深度学习融入 MA-MIMO 系统来估计 DOA 和信道的新方法。在这里，深度信念网络（DBN）被用来学习角度域的空间结构，并通过在线和离线学习程序学习无线信道的统计数据。同时，秃鹰搜索（BES）优化与 DBN 一起使用，通过优化训练达到高精度。建议的模型可以根据预测的 DOA 和复增益来估计信道。根据数值结果，所建议的方法的性能明显优于最先进的方法，尤其是在低信噪比（SNR）和快照数量有限等困难条件下。所提出的 DBN-BES 技术在计算仰角时，信噪比为 5 dB 时的均方根误差（RMSE）小于 0.01；在计算方位角时，信噪比为 5 dB 时的均方根误差（RMSE）小于 0.02。此外，该算法还大大降低了计算复杂度。
{"title":"An optimized deep learning model for a highly accurate DOA and channel estimation for massive MIMO systems","authors":"Omkar H. Pabbati, Rutvij C. Joshi","doi":"10.1002/dac.5902","DOIUrl":"https://doi.org/10.1002/dac.5902","url":null,"abstract":"SummaryMassive multiple‐input multiple‐output (MA‐MIMO) has been hailed as an auspicious technology for the future generation of wireless communications because it can considerably increase the capacity of the communication network. However, using the maximum likelihood (ML) direction‐of‐arrival (DOA) estimate method is severely constrained in actual systems because of the computationally expensive multi‐dimensional searching procedure. This paper proposes a novel approach to estimate DOA and channels by incorporating deep learning into the MA‐MIMO system. Here, a deep belief network (DBN) is used to learn both the spatial structures in the angle domain and the statistics of the wireless channel through both online and offline learning procedures. Also, a bald eagle search (BES) Optimization is used along with DBN to attain high precision through optimal training. The proposed model can estimate the channel based on the predicted DOA and the complex gain. According to numerical results, the suggested method performs significantly better than state‐of‐the‐art methods, particularly in tough conditions like low signal‐to‐noise ratio (SNR) and a finite number of snapshots. The proposed DBN‐BES technique accomplishes less root mean square error (RMSE) as 0.01 for SNR of 5 dB in elevation calculation and 0.02 for SNR of 5 dB in azimuth calculation. Also, the proposed algorithm greatly reduces computational complexity.","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141737935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SummaryWireless sensor networks (WSNs) are becoming increasingly important and well liked for delivering pervasive computing environments for a range of applications. Extending the networking life lifetime in WSNs is an important issue that must be addressed. Effective techniques for conserving the WSN's limited energy resources must be developed. Cross‐layer protocols are employed in WSNs to solve network lifespan difficulties. This paper proposes a new cross‐layer–cross‐domain routing scheme with stages such as “(1) network association stage, (2) nearer node detection phase, and (3) consistent state phase.” In the consistent stage, the optimal cluster head selection (CHS) is carried out by taking into account risk, delay, energy, trust, and distance. A new model called manta ray collided dwarf mongoose optimization (MRC‐DMO) is introduced to help with this. Furthermore, the routing is accomplished by dependable data communication. The results obtained establish the effectiveness of the MRC‐DMO scheme for SEACRCLCD in WSN over varied methods.
{"title":"Secured and energy aware cluster‐based routing in cross‐layer–cross‐domain WSN","authors":"Shivaji R. Lahane, Priti S. Lahane","doi":"10.1002/dac.5896","DOIUrl":"https://doi.org/10.1002/dac.5896","url":null,"abstract":"SummaryWireless sensor networks (WSNs) are becoming increasingly important and well liked for delivering pervasive computing environments for a range of applications. Extending the networking life lifetime in WSNs is an important issue that must be addressed. Effective techniques for conserving the WSN's limited energy resources must be developed. Cross‐layer protocols are employed in WSNs to solve network lifespan difficulties. This paper proposes a new cross‐layer–cross‐domain routing scheme with stages such as “(1) network association stage, (2) nearer node detection phase, and (3) consistent state phase.” In the consistent stage, the optimal cluster head selection (CHS) is carried out by taking into account risk, delay, energy, trust, and distance. A new model called manta ray collided dwarf mongoose optimization (MRC‐DMO) is introduced to help with this. Furthermore, the routing is accomplished by dependable data communication. The results obtained establish the effectiveness of the MRC‐DMO scheme for SEACRCLCD in WSN over varied methods.","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SummaryNew cognitive radio (CR) systems require high throughput and bandwidth. Hence, CR users need to detect wide frequency bands of the radio spectrum to exploit unused frequency channels. This paper proposes a new wideband spectrum sensing (WBSS) detection approach based on machine learning (ML) for scanning subchannels. The originality of the proposed approach is to detect spectrum opportunities using a narrowband spectrum sensing (NBSS) method‐based support vector machine (SVM) classification and two features: energy and goodness of fit (GoF). The simulation results show that the proposed WBSS approach‐based ML presents a higher probability of detection than the WBSS approach‐based conventional detectors, even at low signal‐to‐noise ratio (SNR). Finally, the software defined radio (SDR) implementation validates the proposed WBSS approach for real detection scenarios.
摘要新型认知无线电（CR）系统需要高吞吐量和高带宽。因此，CR 用户需要检测无线电频谱的宽频带，以利用未使用的频率信道。本文提出了一种新的基于机器学习（ML）的宽带频谱感知（WBSS）检测方法，用于扫描子信道。所提方法的独创性在于利用基于支持向量机（SVM）分类的窄带频谱感知（NBSS）方法和两个特征：能量和拟合度（GoF）来检测频谱机会。仿真结果表明，与基于 WBSS 方法的传统检测器相比，即使在信噪比（SNR）较低的情况下，基于 WBSS 方法的 ML 的检测概率也更高。最后，软件定义无线电（SDR）的实现验证了所提出的 WBSS 方法在实际检测场景中的有效性。
{"title":"SDR implementation of wideband spectrum sensing using machine learning","authors":"Zeghdoud Sabrina, Tanougast Camel, Teguig Djamal, Mesloub Ammar, Sadoudi Said, Bouteghrine Belqassim","doi":"10.1002/dac.5907","DOIUrl":"https://doi.org/10.1002/dac.5907","url":null,"abstract":"SummaryNew cognitive radio (CR) systems require high throughput and bandwidth. Hence, CR users need to detect wide frequency bands of the radio spectrum to exploit unused frequency channels. This paper proposes a new wideband spectrum sensing (WBSS) detection approach based on machine learning (ML) for scanning subchannels. The originality of the proposed approach is to detect spectrum opportunities using a narrowband spectrum sensing (NBSS) method‐based support vector machine (SVM) classification and two features: energy and goodness of fit (GoF). The simulation results show that the proposed WBSS approach‐based ML presents a higher probability of detection than the WBSS approach‐based conventional detectors, even at low signal‐to‐noise ratio (SNR). Finally, the software defined radio (SDR) implementation validates the proposed WBSS approach for real detection scenarios.","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141737931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kouros Zanbouri, Mehdi Darbandi, Mohammad Nassr, Arash Heidari, Nima Jafari Navimipour, Senay Yalcın
The latest developments in the industrial Internet of things (IIoT) have opened up a collection of possibilities for many industries. To solve the massive IIoT data security and efficiency problems, a potential approach is considered to satisfy the main needs of IIoT, such as high throughput, high security, and high efficiency, which is named blockchain. The blockchain mechanism is considered a significant approach to boosting data protection and performance. In the quest to amplify the capabilities of blockchain-based IIoT, a pivotal role is accorded to the Glowworm Swarm Optimization (GSO) algorithm. Inspired by the collaborative brilliance of glowworms in nature, the GSO algorithm offers a unique approach to harmonizing these conflicting aims. This paper proposes a new approach to improve the performance optimization of blockchain-based IIoT using the GSO algorithm due to the blockchain's contradictory objectives. The proposed blockchain-based IIoT system using the GSO algorithm addresses scalability challenges typically associated with blockchain technology by efficiently managing interactions among nodes and dynamically adapting to network demands. The GSO algorithm optimizes the allocation of resources and decision-making, reducing inefficiencies and bottlenecks. The method demonstrates considerable performance improvements through extensive simulations compared to traditional algorithms, offering a more scalable and efficient solution for industrial applications in the context of the IIoT. The extensive simulation and computational study have shown that the proposed method using GSO considerably improves the objective function and blockchain-based IIoT systems' performance compared to traditional algorithms. It provides more efficient and secure systems for industries and corporations.
{"title":"A GSO-based multi-objective technique for performance optimization of blockchain-based industrial Internet of things","authors":"Kouros Zanbouri, Mehdi Darbandi, Mohammad Nassr, Arash Heidari, Nima Jafari Navimipour, Senay Yalcın","doi":"10.1002/dac.5886","DOIUrl":"10.1002/dac.5886","url":null,"abstract":"<div>\u0000 \u0000 <p>The latest developments in the industrial Internet of things (IIoT) have opened up a collection of possibilities for many industries. To solve the massive IIoT data security and efficiency problems, a potential approach is considered to satisfy the main needs of IIoT, such as high throughput, high security, and high efficiency, which is named blockchain. The blockchain mechanism is considered a significant approach to boosting data protection and performance. In the quest to amplify the capabilities of blockchain-based IIoT, a pivotal role is accorded to the Glowworm Swarm Optimization (GSO) algorithm. Inspired by the collaborative brilliance of glowworms in nature, the GSO algorithm offers a unique approach to harmonizing these conflicting aims. This paper proposes a new approach to improve the performance optimization of blockchain-based IIoT using the GSO algorithm due to the blockchain's contradictory objectives. The proposed blockchain-based IIoT system using the GSO algorithm addresses scalability challenges typically associated with blockchain technology by efficiently managing interactions among nodes and dynamically adapting to network demands. The GSO algorithm optimizes the allocation of resources and decision-making, reducing inefficiencies and bottlenecks. The method demonstrates considerable performance improvements through extensive simulations compared to traditional algorithms, offering a more scalable and efficient solution for industrial applications in the context of the IIoT. The extensive simulation and computational study have shown that the proposed method using GSO considerably improves the objective function and blockchain-based IIoT systems' performance compared to traditional algorithms. It provides more efficient and secure systems for industries and corporations.</p>\u0000 </div>","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141644990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reconfigurable fractal antenna (RFA) design is always necessary for the continued development of wireless communication systems as the antenna is playing a vital part in device performance. The need for efficient radiators that are compact, low‐profile, inexpensive, and low weight has attracted scientists for their research works. As a result, numerous ideas were put forward by the researchers to attempt to resolve these problems by utilizing various kinds of fractal and reconfigurable antennas as well as their combinations. However, it is challenging to have a clear and transparent review of the various works with a large variety of solutions and their uniqueness. The advanced RFA design for wireless applications is reviewed in this study together with its most recent and pertinent counterparts. In Koch RFA, bandwidths enable selective bands spanning 1–6 GHz frequency range. Further, in band RFA design, the overall bandwidth ranges from 1.45 to 4.52 GHz (103%) with low gain; on the other hand, the crescent RFA achieves 5.67 dBi peak gain. Furthermore, in polarization RFA, the ARBWs are 17.61% (2.2–2.62 GHz) and 8.69% (2.91–3.18 GHz). The Hilbert RFA operates at 0.9 and 2.45 GHz with gains of 3.1 and 7 dBi, respectively. This article investigates a comprehensive review of the requirements for RFAs for wireless applications. Furthermore, a comparative study on different reconfigurability with switching techniques, fractal geometries, various RFA design approaches to enhance device performance, and their significance is discussed. Existing research challenges and future directions are also discussed as part of this article.
{"title":"Reconfigurable fractal antennas for future wireless applications: A comprehensive review","authors":"Khushbu Patel, S. K. Behera","doi":"10.1002/dac.5910","DOIUrl":"https://doi.org/10.1002/dac.5910","url":null,"abstract":"Reconfigurable fractal antenna (RFA) design is always necessary for the continued development of wireless communication systems as the antenna is playing a vital part in device performance. The need for efficient radiators that are compact, low‐profile, inexpensive, and low weight has attracted scientists for their research works. As a result, numerous ideas were put forward by the researchers to attempt to resolve these problems by utilizing various kinds of fractal and reconfigurable antennas as well as their combinations. However, it is challenging to have a clear and transparent review of the various works with a large variety of solutions and their uniqueness. The advanced RFA design for wireless applications is reviewed in this study together with its most recent and pertinent counterparts. In Koch RFA, bandwidths enable selective bands spanning 1–6 GHz frequency range. Further, in band RFA design, the overall bandwidth ranges from 1.45 to 4.52 GHz (103%) with low gain; on the other hand, the crescent RFA achieves 5.67 dBi peak gain. Furthermore, in polarization RFA, the ARBWs are 17.61% (2.2–2.62 GHz) and 8.69% (2.91–3.18 GHz). The Hilbert RFA operates at 0.9 and 2.45 GHz with gains of 3.1 and 7 dBi, respectively. This article investigates a comprehensive review of the requirements for RFAs for wireless applications. Furthermore, a comparative study on different reconfigurability with switching techniques, fractal geometries, various RFA design approaches to enhance device performance, and their significance is discussed. Existing research challenges and future directions are also discussed as part of this article.","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141650032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SummarySolar‐powered devices, such as wireless networks, are a crucial component of the Internet of Things (IoT). Designing and creating a solar cell architecture with an extended light absorption regime at a reasonable cost is therefore exceedingly important. All inorganic bismuth‐based Cs2AgBiI6 planar perovskite solar cells (PSCs) have garnered enormous significance due to their exceptional stability against oxygen, heat, and moisture. However, the power conversion efficiencies of Cs2AgBiI6‐based planar PSCs remain relatively low, primarily due to their limited light absorption range and interfacial charge recombination losses. This issue can be effectively addressed using a novel multi‐absorber architecture that incorporates dual absorbers with both lower band gap and wider band gap materials. This approach extends the light absorption range, enabling maximal utilization of the solar spectrum. Therefore, this article incorporates numerical modeling and guided optimization of ITO/ETL/Cs2AgBiI6/Fa0.75Cs0.25SnI3/HTL/Ag dual absorber‐based heterojunction structure to improvise the power conversion efficiency of Cs2AgBiI6‐based single‐absorber PSCs. The proposed configuration employs dual perovskite absorber layers (PALs) consisting of wide band gap Cs2AgBiI6 (1.6 eV) as the top absorber layer along with narrow bandgap Fa0.75Cs0.25SnI3 (1.27 eV) to act as the bottom absorber layer. Before evaluating the bilayer configuration, two standalone PSC architectures, namely, ITO/ETL/Fa0.75Cs0.25SnI3/HTL/Ag (D1)‐ and ITO/ETL/Cs2AgBiI6/HTL/Ag (D2)‐based PSC have been simulated and computed to perfectly fit the earlier anticipated state of art results. After effective validation of the photovoltaic parameters of the standalone architectures, both the absorber layers are appraised to constitute a dual active layer configuration ITO/ETL/Cs2AgBiI6/Fa0.75Cs0.25SnI3/HTL/Ag (D3) maintaining the overall absorber layer width constant to elevate the overall solar cell efficiency. Herein, a combination of various competent hole transport layers (HTLs) such as CBTS, CFTS, Cu2O, CuI, CuO, CuSCN, P3HT, PEDOT:PSS, and Spiro‐OMeTAD, as well as electron transport layers (ETLs) like C60, CeO2, IgZo, PCBM, TiO2, WS2, and ZnO, are adopted and compared to attain highly efficient bilayer PSC configuration. The crucial variables of all ETL‐
{"title":"Device engineering of lead‐free FaCsSnI3/Cs2AgBiI6‐based dual‐absorber perovskite solar cell architecture for powering next‐generation wireless networks","authors":"Smriti Baruah, Janmoni Borah, Perugu Yaswanth Reddy, Chamarthi Sindhupriya, Nara Sathvika, Subramaniam Rajasekaran","doi":"10.1002/dac.5903","DOIUrl":"https://doi.org/10.1002/dac.5903","url":null,"abstract":"SummarySolar‐powered devices, such as wireless networks, are a crucial component of the Internet of Things (IoT). Designing and creating a solar cell architecture with an extended light absorption regime at a reasonable cost is therefore exceedingly important. All inorganic bismuth‐based Cs<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub> planar perovskite solar cells (PSCs) have garnered enormous significance due to their exceptional stability against oxygen, heat, and moisture. However, the power conversion efficiencies of Cs<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub>‐based planar PSCs remain relatively low, primarily due to their limited light absorption range and interfacial charge recombination losses. This issue can be effectively addressed using a novel multi‐absorber architecture that incorporates dual absorbers with both lower band gap and wider band gap materials. This approach extends the light absorption range, enabling maximal utilization of the solar spectrum. Therefore, this article incorporates numerical modeling and guided optimization of ITO/ETL/Cs<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub>/Fa<jats:sub>0.75</jats:sub>Cs<jats:sub>0.25</jats:sub>SnI<jats:sub>3</jats:sub>/HTL/Ag dual absorber‐based heterojunction structure to improvise the power conversion efficiency of Cs<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub>‐based single‐absorber PSCs. The proposed configuration employs dual perovskite absorber layers (PALs) consisting of wide band gap Cs<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub> (1.6 eV) as the top absorber layer along with narrow bandgap Fa<jats:sub>0.75</jats:sub>Cs<jats:sub>0.25</jats:sub>SnI<jats:sub>3</jats:sub> (1.27 eV) to act as the bottom absorber layer. Before evaluating the bilayer configuration, two standalone PSC architectures, namely, ITO/ETL/Fa<jats:sub>0.75</jats:sub>Cs<jats:sub>0.25</jats:sub>SnI<jats:sub>3</jats:sub>/HTL/Ag (D1)‐ and ITO/ETL/Cs<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub>/HTL/Ag (D2)‐based PSC have been simulated and computed to perfectly fit the earlier anticipated state of art results. After effective validation of the photovoltaic parameters of the standalone architectures, both the absorber layers are appraised to constitute a dual active layer configuration ITO/ETL/Cs<jats:sub>2</jats:sub>AgBiI<jats:sub>6</jats:sub>/Fa<jats:sub>0.75</jats:sub>Cs<jats:sub>0.25</jats:sub>SnI<jats:sub>3</jats:sub>/HTL/Ag (D3) maintaining the overall absorber layer width constant to elevate the overall solar cell efficiency. Herein, a combination of various competent hole transport layers (HTLs) such as CBTS, CFTS, Cu<jats:sub>2</jats:sub>O, CuI, CuO, CuSCN, P3HT, PEDOT:PSS, and Spiro‐OMeTAD, as well as electron transport layers (ETLs) like C<jats:sub>60</jats:sub>, CeO<jats:sub>2</jats:sub>, IgZo, PCBM, TiO<jats:sub>2</jats:sub>, WS<jats:sub>2</jats:sub>, and ZnO, are adopted and compared to attain highly efficient bilayer PSC configuration. The crucial variables of all ETL‐ ","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141610080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Emmanuel Ampoma Affum, Samuel Tweneboah‐Koduah, Michael Kubi Appiah, Eric Gyamfi, Sunday Adeola Ajagbe, Owusu Agyeman Antwi, Matthew Adigun
Wireless Powered Communication Networks (WPCNs) represent a transformative approach to address the energy demands of mobile and Internet of Things (IoT) devices. By integrating Nonorthogonal Multiple Access (NOMA) and Intelligent Reflecting Surfaces (IRS), we can significantly enhance system performance, extend coverage, and elevate the sum rate. NOMA efficiently utilizes the entire bandwidth by employing a power allocation strategy, whereas IRS, serving as an alternative to traditional relay amplification, further bolsters the sum rate. Despite these advancements, optimizing the sum rate introduces a nonconvex optimization challenge, primarily owing to the signal‐to‐interference‐plus‐noise ratio (SINR) complexities introduced by NOMA's Successive Interference Cancellation (SIC). Traditional convex optimization solvers, such as the CVX, struggle to address nonconvexity directly. Consequently, they were unable to produce the desired outcome. Moreover, the combination of multiple technologies to improve the sum rate complicates the optimization framework, necessitating a multitude of constraints that not only heightens the mathematical complexity but also induces errors through the requisite approximations for convexity conversion. To circumvent these hurdles, we advocate the application of a minimum constrained nonlinear multivariable function (Fmincon). This approach enables us to tackle the nonconvex problem head‐on, maintaining consistent simulation parameters while limiting constraints to two pivotal factors: joint optimization of the transmit power ( ) and transmit time ( ). This strategic simplification mitigates complexity and minimizes errors. Our numerical analyses confirmed the efficacy of the proposed model and optimization technique. By co‐optimizing the transmission power and time, we achieved a notable sum rate. Comparative evaluations with extant models underscored the superior performance of our proposed framework, marking a significant stride in WPCN advancement.
{"title":"Maximization of sum rate for Wireless Powered Communication Network with Intelligent Reflecting Surface and NOMA in the nonappearance of uplink and downlink beamforming matrix, subject to transmit power and time","authors":"Emmanuel Ampoma Affum, Samuel Tweneboah‐Koduah, Michael Kubi Appiah, Eric Gyamfi, Sunday Adeola Ajagbe, Owusu Agyeman Antwi, Matthew Adigun","doi":"10.1002/dac.5911","DOIUrl":"https://doi.org/10.1002/dac.5911","url":null,"abstract":"Wireless Powered Communication Networks (WPCNs) represent a transformative approach to address the energy demands of mobile and Internet of Things (IoT) devices. By integrating Nonorthogonal Multiple Access (NOMA) and Intelligent Reflecting Surfaces (IRS), we can significantly enhance system performance, extend coverage, and elevate the sum rate. NOMA efficiently utilizes the entire bandwidth by employing a power allocation strategy, whereas IRS, serving as an alternative to traditional relay amplification, further bolsters the sum rate. Despite these advancements, optimizing the sum rate introduces a nonconvex optimization challenge, primarily owing to the signal‐to‐interference‐plus‐noise ratio (SINR) complexities introduced by NOMA's Successive Interference Cancellation (SIC). Traditional convex optimization solvers, such as the CVX, struggle to address nonconvexity directly. Consequently, they were unable to produce the desired outcome. Moreover, the combination of multiple technologies to improve the sum rate complicates the optimization framework, necessitating a multitude of constraints that not only heightens the mathematical complexity but also induces errors through the requisite approximations for convexity conversion. To circumvent these hurdles, we advocate the application of a minimum constrained nonlinear multivariable function (Fmincon). This approach enables us to tackle the nonconvex problem head‐on, maintaining consistent simulation parameters while limiting constraints to two pivotal factors: joint optimization of the transmit power ( ) and transmit time ( ). This strategic simplification mitigates complexity and minimizes errors. Our numerical analyses confirmed the efficacy of the proposed model and optimization technique. By co‐optimizing the transmission power and time, we achieved a notable sum rate. Comparative evaluations with extant models underscored the superior performance of our proposed framework, marking a significant stride in WPCN advancement.","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141610081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SummaryMultiple‐input multiple‐output (MIMO) radar, employing multiple transmitters and receivers, enhances radar capabilities. It detects and tracks objects like aircraft and ships using radio waves. Compared with traditional phased‐array radar, MIMO systems offer greater flexibility, improving angular resolution and target detection. Researchers focus on direction of arrival (DoA) evaluation for closely spaced targets. Effective beamforming and accurate DoA estimation are crucial for MIMO radar performance. This study explores two methods: Capon beamforming with Dolph–Chebyshev windowing and the MUSIC algorithm with Eigenvalue thresholding. Tested under low signal‐to‐noise ratio (SNR) and fewer snapshots, these techniques notably reduce side lobes and enhance angular resolution, validated by experiments. Additionally, the suppression of side lobes significantly improves the clarity and accuracy of target detection, minimizing potential interference and false targets. This enhancement in side lobe suppression facilitates a more precise spatial differentiation between multiple targets, thus contributing to the overall effectiveness and reliability of MIMO radar systems.
摘要多输入多输出（MIMO）雷达采用多个发射器和接收器，增强了雷达功能。它利用无线电波探测和跟踪飞机和船只等物体。与传统的相控阵雷达相比，MIMO 系统具有更大的灵活性，可提高角度分辨率和目标探测能力。研究人员的重点是对间距较近的目标进行到达方向（DoA）评估。有效的波束成形和准确的到达方向估计对 MIMO 雷达的性能至关重要。本研究探讨了两种方法：带有 Dolph-Chebyshev 窗口的 Capon 波束成形和带有特征值阈值的 MUSIC 算法。在信噪比（SNR）较低和快照较少的情况下进行测试，这些技术显著减少了侧叶，提高了角度分辨率，并得到了实验的验证。此外，抑制边叶还能显著提高目标检测的清晰度和准确性，最大限度地减少潜在干扰和错误目标。侧叶抑制的增强有助于更精确地区分多个目标，从而提高多输入多输出雷达系统的整体有效性和可靠性。
{"title":"Novel approaches for target parameter extraction with eigenvalue thresholding and Dolph–Chebyshev windowing in multiple‐input multiple‐output (MIMO) radar system","authors":"Sheetal G. Jagtap, Ashwini S. Kunte","doi":"10.1002/dac.5912","DOIUrl":"https://doi.org/10.1002/dac.5912","url":null,"abstract":"SummaryMultiple‐input multiple‐output (MIMO) radar, employing multiple transmitters and receivers, enhances radar capabilities. It detects and tracks objects like aircraft and ships using radio waves. Compared with traditional phased‐array radar, MIMO systems offer greater flexibility, improving angular resolution and target detection. Researchers focus on direction of arrival (DoA) evaluation for closely spaced targets. Effective beamforming and accurate DoA estimation are crucial for MIMO radar performance. This study explores two methods: Capon beamforming with Dolph–Chebyshev windowing and the MUSIC algorithm with Eigenvalue thresholding. Tested under low signal‐to‐noise ratio (SNR) and fewer snapshots, these techniques notably reduce side lobes and enhance angular resolution, validated by experiments. Additionally, the suppression of side lobes significantly improves the clarity and accuracy of target detection, minimizing potential interference and false targets. This enhancement in side lobe suppression facilitates a more precise spatial differentiation between multiple targets, thus contributing to the overall effectiveness and reliability of MIMO radar systems.","PeriodicalId":13946,"journal":{"name":"International Journal of Communication Systems","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141610082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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