International Journal of Communication Systems最新文献

This research proposes a novel low-cost aperture coupled elliptic patch nanoantenna which works best when it has a stable radiation pattern and good gain. On the upper portion of the substratum, a cross-shaped hole was additionally engraved from a metallic strip with a silver composition. Elliptical-shaped silicon material is employed as a patch in this antenna design which is made on a substrate made of inexpensive glass epoxy. The silver substance makes up the nanometallic strip line at the substrate's base. A cross-shaped hole has also been etched from a metallic strip with a silver composition on the upper section of the substrate. As the foam substrate to be used in between the feed and antenna substrates, Rohacell was adopted. A proposed simple cross-shaped aperture enhanced the bandwidth of the planned antenna without degrading its radiation performance and is loaded on a proximity-linked elliptical microstrip antenna. To achieve the highest coupling, the lowest back radiation, the least amount of spurious radiation, and good efficiency, the patch and feed line are positioned in the middle, at a right angle over the slot. The proposed antenna was simulated in HFSS, and optimum results were observed from the output. The results were evaluated based on radiation pattern, return loss, smith chart, radiation efficiency, and 3D polar plot for 300, 500, and 800 THz frequencies. Also, the impedance bandwidth, gain, and a number of bands were compared with other conventional methods and our proposed method proved to outperform the existing method in all aspects.

This research study proposes a combined filter-antenna design by employing stepped impedance resonator (SIR) techniques. The filtering antenna is designed around the unlicensed frequency band of 5.3 and 5.6 GHz. The filtenna realizes an insertion loss of −3.15 dB and return loss of −22 dB in the frequency band of 5.3 GHz and further −17.8 dB return loss in the 5.6-GHz band. The developed filtenna achieves omni-directional radiation pattern suitable for unlicensed applications with better selectivity and also results in low reflection loss. The observed voltage standing wave ratio is 1.6, and antenna gain is approximately 6.2 dBi in the 5.6-GHz band. The simulation results obtained align consistently with real-time measurements.

This paper considers multiuser downlink transmission and detection in a multiple input-multiple output (MIMO) visible light communication (VLC) system. We combine two promising techniques: space-shift keying (SSK) and optical orthogonal codes (OOCs). Multiuser downlink transmission is realized by allowing each activated LED to transmit user-specific OOC simultaneously. An OOC despreader is implemented at the front end of each user terminal (UT) to extract the desired signal and mitigate multiuser interference (MUI). The second part of UT receiver aims to extract the index of the corresponding active LED based on maximum likelihood (ML) or zero-forcing (ZF) algorithm. The figure of merit we used to access the performance of the proposed downlink multiuser SSK system is the average symbol error rate (SER). Comprehensive Monte Carlo simulations have been undertaken for different system setup to evaluate SER at UT receiver. It is demonstrated that for a specified SER, the required SNR for ML-based detection algorithm is 3 dB less than the ZF detector in the MUI-free scenario. On the other hand, the ZF detector outperforms ML detector in the case with residual MUI and limited channel state information (CSI). Both algorithms are computationally attractive, hence can be put into practice in multiuser VLC MIMO system.

Channel coding is the most significant part of every communication system. Future wireless systems will require extraordinary performance codes employing a low-complication encoding process and decoding to accommodate scenarios ranging from effective throughput with low code rates for extended messages to high dependability for brief information messages with low code rates. The existence of digital transmission techniques that can communicate error-free over a noisy channel is established by Shannon's channel theorem. Channel coding, however, increases communication dependability at the cost of higher computational costs and structured redundancy. The primary goals of the fifth-generation cellular network (5G) are enhanced dependability, reduced redundancy, and decreased latency. Two promising communication systems for achieving this goal are LDPC codes and polar codes. The 3GPP, which established the 5G communication system, is reviewed in this paper, along with the encoding/decoding procedure and communication dependability. The encoding/decoding process will be evaluated using the three most studied communication channels: the Binary Erasure Channel (BEC), AWGN (Additive White Gaussian Noise), and the BSC (Binary Symmetric Channel).

In the world of emerging wireless networks, interference poses a significant challenge to reliable wireless communication. Additionally, these networks are prone to path loss and blockages, which can be addressed by utilizing the advanced technology of multihop communication with instantaneous relay (IR). However, scenarios involving IR-assisted networks are considered instances of multihop communications that face potential obstacles caused by interference. As a result, multiple interference management approaches exist to tackle this interference issue, among which aligned interference neutralization (AIN) is a state-of-the-art technology that seamlessly unifies two established interference management strategies: interference alignment (IA) and interference neutralization (IN). Therefore, this paper presents a novel tristaged AIN scheme to mitigate interference in a multicellular multiple-input multiple-output (MIMO) interference multiple access channel (IMAC). In the proposed scheme, the initial stage-1 involves transmitting message signals from individual transmitters or users to the IR and the receiving base stations (BSs). In stage-2, the IR neutralizes half of the interference signals by performing IN. Finally, in stage-3, IA is carried out at the receiver BS terminals, aligning the remaining interference signals equally within the available dimensions. Based on this proposed approach, we determined that for an IR-aided multicellular MIMO IMAC, the achievable degree of freedom (DoF) is 2N. The proposed approach's robustness and effectiveness have been analyzed through extensive simulations, and these simulation results indicated that the proposed approach outperforms other benchmark interference management techniques in terms of DoF and sum rate, thereby improving user performance.

Wireless body sensor network (WBSN) is essential for monitoring patients' health problems and offers a low-cost option for various healthcare applications. In this manuscript, a Novel Health Monitoring Approach for WBSNs (DIWGAN-WBSN) is proposed, which uses Dual Interactive Wasserstein Generative Adversarial Network (DIWGAN) optimized with War Strategy Optimization Algorithm (WSOA). After sensing the aforementioned attribute information, it is the responsibility of WBSN nodes to transfer the sensed data to the sink node. The Volcano Eruption Algorithm (VEA) is applied to select the optimum cluster heads in WBSN. The results from VEA are fed to the target node; it consists of DIWGAN to classify the health records and to portray the patient's health status. Generally, DIWGAN does not adopt any optimization methods for measuring the ideal parameters and guaranteeing accurate health monitoring and risk assessment. So the proposed WSOA is considered to enhance the DIWGAN. The proposed method is activated in MATLAB; its efficacy is estimated under performance metrics, like precision, specificity, accuracy, and energy utilization. The proposed approach attains 23.9%, 21.34%, and 51.09% higher accuracy; 21.45%, 13.94%, and 20.6% higher precision; 31.32%, 29.61%, and 11.03% higher specificity; and 20.9%, 19.87%, and 24.6% lower energy utilization for HD classification using the Cleveland database than the existing methods like back propagation neural network-based risk detection in WBSN for health monitoring, random forest algorithm–based health monitoring in WBSN, and ensemble deep learning and feature fusion for health monitoring using WBSN methods, respectively.

Deep learning (DL)-based channel estimation for orthogonal frequency division multiplexing with index modulation (OFDM-IM) under Rayleigh fading channel conditions is presented in this paper. A deep neural network (DNN) is utilized to estimate the channel response in simulations. The proposed DNN is trained using the channel coefficient derived through the least squares (LS) method. Then channel estimation is conducted using the trained DNN. Within the DNN, the long short-term memory (LSTM) layer is included as the hidden layer. Different scenarios are handled in simulations and the proposed DNN is compared with traditional channel estimation methods. The simulations demonstrate that the DL-based channel estimation significantly surpasses the LS and minimum mean-square error (MMSE) techniques.

Optimizing node deployment in the underwater Internet of Things (UIoT) poses significant challenges due to the complex and dynamic nature of underwater environments. This research introduces the adaptive long short-term memory-based egret swarm optimization algorithm (ALSTM-ESOA), a novel approach designed to enhance network coverage and performance efficiently. Unlike traditional methods, ALSTM-ESOA incorporates cognitive learning capabilities from long short-term memory (LSTM) and dynamic adaptation strategies inspired by the hunting behaviors of egrets. The algorithm's effectiveness was tested through extensive simulations in MATLAB, demonstrating notable improvements over existing models: network throughput increased by up to 55.56%, deployment time decreased by 88.89%, and energy efficiency improved significantly. These enhancements are critical for robust, real-time data collection and monitoring in underwater settings, providing substantial benefits for marine research and resource management. The findings suggest that ALSTM-ESOA significantly outperforms conventional algorithms, offering a promising new tool for the advancement of UIoT applications. After being implemented in MATLAB, the suggested ALSTM-ESOA model for the node deployment optimization in UIoT is examined. The proposed ALSTM-ESOA in terms of network throughput is 55.56%, 38.89%, 36.11%, and 11.11% better than CNN, LSTM, ARO-RTP, and IGOR-TSA, respectively. Similarly, the proposed ALSTM-ESOA with respect to deployment time is 88.89%, 81.82%, 75%, and 50% better than CNN, LSTM, ARO-RTP, and IGOR-TSA, respectively. For the purpose of exploring marine resources, monitoring underwater environments, and conducting marine scientific investigation, the research's findings are extremely valuable.

In this work, an offset microstrip line coupled bilateral rectangular-shaped dielectric resonator antenna (RDRA) is designed for broadband circular polarization (CP), which is fabricated and experimentally verified. The vertical microstrip is added in an offset position to generate orthogonal modes and the fundamental modes TE^x₁₁₁ and TE^y₁₁₁. The generation of orthogonal modes designates the antenna structure as a CP antenna with orthogonal modes. Moreover, the location of the microstrip feed arrangement is used to control the polarization state in the proposed work. In the proposed design, the simulated and hand-measured input impedance bandwidth(|S₁₁| ≤ −10 dB) obtained is 32.6% (3.53–4.9 GHz) and 33.2% (3.56–4.98 GHz), respectively, whereas the simulated and measured axial ratio (AR ≤ 3 dB) shows 16.1% (3.71–4.36 GHz) and 17.03% (3.7–4.39 GHz) of axial ratio bandwidth, respectively. This design shows a consistent radiation pattern and good average gain, with acceptable agreement between simulation and hand-measured results. The simulated result shows 94% radiation efficiency in the working frequency range.

A comparative analysis of 3D positioning error for two different configurations using different layouts of visible light communication (VLC) systems is presented in this paper. The Received Signal Strength (RSS) has been implemented for indoor localization systems using Line-of-Sight (LoS) and diffused reflection signals. The room size for configuration-1 is 5 m × 5 m × 3 m, and the distance between adjacent LEDs is 2.5 m, 2.00 m, and 1.5 m for cases-1, case-2, and case-3, respectively, whereas the room size for configuration-2 is 7 m × 7 m × 5 m, and the separation between the LEDs is 3.5 m, 3 m, and 2.5 m for their respective cases. Through investigation, it has been shown that when only LS signal is considered, the separation between LEDs may not be an issue because positioning error changes by a very small amount as the separation between LEDs changes. The results show that as the distance between adjacent LEDs decreases, the received signal strength for LoS and L-R1 signals increases. However, positioning error and BER rise, while the bit rate falls. Furthermore, the positioning error Vs receiver plane height for all three cases in configuration-1 is the same up to a height of 2.89 m, whereas the positioning error in configuration-2 is the same up to 4.4 m for all cases. The positioning error for case-1 decreases as the height in configuration-1 exceeds 2.89 m. Similarly, after reaching a height of 4.4 m for case-2, the positioning error in configuration-2 decreases. The LoS positioning error versus semi angle $�{\phi }_{�1�/�2�}$ of the LED as well as the FOV of the receiver has been simulated for different positions of the receiver in configuration-1. The investigation shows that the minimum positioning error is achieved at $�{\phi }_{�1�/�2�}$ and FOV equal to 66.66⁰ for all the positions of the receiver in the room. Thus, before configuring a practical indoor VLC geometrical model, proper VLC configurations such as LED separation, FOV of the receiver, semi angle of LED, and receiver height should be chosen based on the room dimensions.