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Location-based Power Control Mechanism for D2D Communication Underlaying a Cellular System, Journal of Telecommunications and Information Technology, 2023, nr 3
Full text linkThe paper presents a location-based approach to controlling the power of device-to-device (D2D) underlay of a frequency reuse-1 cellular system. The system allows for direct communication to share uplink resources with cellular users. As a result, both D2D and cellular users are experiencing additional interferences in the system. By controlling the output power of the devices, these interferences can be mitigated and the performance of the network can be improved in terms of better spectral and energy efficiency. The proposed location-based target signal-to-interference ratio power control scheme for D2D communications utilizes information about users' locations to estimate the interference level experienced by the receiver of the direct link. Based on this estimation, an appropriate transmit power can be determined. The performance of the proposed power control solution is investigated via system level simulations
Efficient Iterative Detection Based on Conjugate Gradient and Successive Over-Relaxation Methods for Uplink Massive MIMO Systems, Journal of Telecommunications and Information Technology, 2023, nr 2
Full text linkBeing a crucial aspect of fifth-generation (5G) mobile communications systems, massively multiple-input multipleoutput (mMIMO) architectures are expected to help achieve the highest key performance indicators. However, the huge numbers of antennas used in such systems make it difficult to determine the inversion of the signal channel matrix relied upon by several detection methods, hence posing a problem with accurate estimation of the symbols sent. In this paper, conjugate gradient (CG) and successive over-relaxation (SOR) methods are selected to construct a new iterative approach that avoids the matrix inversion computation issue. This suggested approach for uplink mMIMO detection is based on a joint cascade structure of both iterative methods. The CG method is first applied and adjusted for the initial solution, followed by the SOR method in the final iterations for terminal computations, resulting in an algorithm with robust performance and low computational complexity. Furthermore, the new hybrid scheme operates based on the relaxation parameter, whose value has a great impact on error performance and, whose optimal determination is necessary. Numerical simulations reveal that the proposed scheme is capable of significantly improving signal detection accuracy with minimum complexity. The simulation results indicated that the proposed detector outperforms CG and SOR detectors, achieves close to optimal performance, requires fewer iterations, and reduces complexit
Improving Quality of Watermarked Medical Images Using Symmetric Dilated Convolution Neural Networks, Journal of Telecommunications and Information Technology, 2023, nr 2
Full text linkRapid development of online medical technologies raises questions about the security of the patient’s medical data.When patient records are encrypted and labeled with a watermark, they may be exchanged securely online. In order to avoid geometrical attacks aiming to steal the information, image quality must be maintained and patient data must be appropriately extracted from the encoded image. To ensure that watermarked images are more resistant to attacks (e.g. additive noise or geometric attacks), different watermarking methods have been invented in the past. Additive noise causes visual distortion and render the potentially harmful diseases more difficult to diagnose and analyze. Consequently, denoising is an important pre-processing method for obtaining superior outcomes in terms of clarity and noise reduction and allows to improve the quality of damaged medical images. Therefore, various publications have been studied to understand the denoising methods used to improve image quality. The findings indicate that deep learning and neural networks have recently contributed considerably to the advancement of image processing techniques. Consequently, a system has been created that makes use of machine learning to enhance the quality of damaged images and to facilitate the process of identifying specific diseases. Images, damaged in the course of an assault, are denoised using the suggested technique relying on a symmetric dilated convolution neural network. This improves the system’s resilience and establishes a secure environment for the exchange of data while maintaining secrecy
Remedies to Thermal Radiation in Fused Silica Optical Fibers, Journal of Telecommunications and Information Technology, 2023, nr 1
Full text linkDuring fire incidents, optical fibers located with-in a fire-resistant cable are usually exposed to temperatures of 800ºC to 1000ºC. Hot fibers generate narrowband thermal (incandescent) radiation and collect broadband thermal radiation originating from the heated surroundings. The power of the second component, initially negligible, increases with time due to the rising number of fiber cracks and other defects acting as couplers for external radiation. Thermal radiation may interfere with fiber attenuation measurements performed during a fire test, but is rather unlikely to prevent data transmission with typical GbE and 10 GbE transceivers during a fire. This problem may be remedied by combining the following methods: using single mode fibers instead of multimode fibers, using bandpass filters to block thermal radiation, and selecting proper transmitter power, wavelength and photodetector
Single Linkage Weighted Steepest Gradient Adaboost Cluster-Based D2D in 5G Networks, Journal of Telecommunications and Information Technology, 2023, nr 1
Full text linkEfficiency of data transmissions with minimum latency levels and better resource utilization is a challenging issue in 5 G device-to-device (D 2D) environments. A novel technique referred to as single linkage steepest gradient gentle AdaBoost cluster-based device (SLSGAC) is introduced to improve device-to-device communications with minimum latency. The proposed technique uses the ensemble clustering approach to group mobile devices by constructing a set of weak clusters, based on the Minkowski single linkage clustering technique. In the weak clustering process, residual energy, bandwidth and SINR are estimated, and mobile devices are grouped based on the Minkowski distance measure. Results of the weak clustering process are combined to provide the final ensemble’s clustering output by applying the steepest gradient function to minimize the error rate. For each cluster, a head is selected from among the group members to improve the data transmission rate and minimize latency. Simulations are conducted comparing the proposed technique with the existing methods based on such metrics as energy efficiency, data delivery ratio, packet loss rate, throughput and latency
Design of a Microstrip Filtering Antenna for 4G and 5G Wireless Networks, Journal of Telecommunications and Information Technology, 2023, nr 2
Full text linkThe filtering antenna provides both radiation and filtering features and is an important component for the RF front-end of wireless devices. The main function of a filtering antenna is to reject out-of-band signals, thus reducing the interference from adjacent channels. The aim of the present work is to design a 2.6 GHz microstrip filtering antenna for 4G and 5G global mobile services. The filtering antenna is designed using a hairpin bandpass filter integrated with an elliptical microstrip aerial. Good impedance matching is obtained by using appropriate dimensions of the hairpin bandpass filter. The 10 dB return loss bandwidth of the filtering antenna is approx. 5.7%, with the maximum gain for the elliptical filtering antenna of approx. 2.2 dB. Good agreements between the measured and simulated results are obtained for the proposed filtering antenna and the bandwidth covers almost the entire 2.6 GHz band
Utilization of Reconfigurable Intelligent Surfaces with Context Information: Use Cases, Journal of Telecommunications and Information Technology, 2023, nr 3
Full text linkUtilization of reconfigurable intelligent surfaces is a topic that is very interesting in the context of complex radio environments, especially those used in dense urban areas. By relying on simple solutions to control the angle of reflection of the signal from the surface, different effects may be achieved in radio communication systems. Maximization or minimization of the received power at specific locations near the reflecting surface is the most important effect. This phenomenon allows to: receive a signal at a location at which it could not be received previously, detect spectrum occupancy at a place where the sensor could not perform a correct detection, or minimize interference affecting a specific receiver. In this paper, all three concepts are presented and a simple ray tracing simulation is used to show the potential profits attainable in each of the scenarios. Additionally, a scenario was analyzed in which several of the aforementioned situations are combined
Why Is White Noise Not Enough? Using Radio Front-End Models While Designing 6G PHY, Journal of Telecommunications and Information Technology, 2023, nr 2
Full text linkEach subsequent generation of wireless standards imposes stricter spectral and energy efficiency demands. So far, layered wireless transceiver architectures have been used, allowing for instance to separate channel decoding algorithms from the front-end design. Such an approach may need to be reconsidered in the upcoming 6G era. Especially hardware-originated distortions have to be taken into account while designing other layer algorithms, as high throughput and energy efficiency requirements will push these devices to their limits, revealing their non-linear characteristics. In such a context, this paper will shed some light on the new degrees of freedom enjoyed while cross-layer designing as well as controlling multicarrier and multiantenna transceivers in 6G systems
Preserving Integrity of Evidence with Blockchain Technology in Cloud Forensics for Immigration Management, Journal of Telecommunications and Information Technology, 2023, nr 1
Full text linkAs the popularity of cloud computing increases, safety concerns are growing as well. Cloud forensics (CF) is a smart adaptation of the digital forensics model that is used for fighting the related offenses. This paper proposes a new forensic method relying on a blockchain network. Here, the log files are accumulated and preserved in the blockchain using different peers. In order to protect the system against illegitimate users, an improved blowfish method is applied. In this particular instance, the system is made up of five distinct components: hypervisor (VMM), IPFS file storage, log ledger, node controller, and smart contract. The suggested approach includes six phases: creation of the log file, key setup and exchange, evidence setup and control, integrity assurance, agreement validation and confidential file release, as well as blockchain-based communication. To ensure efficient exchange of data exchange between the cloud provider and the client, the methodology comprises IPFS. The SSA (FOI-SSA) model, integrated with forensic operations, is used to select the keys in the best possible way. Finally, an analysis is conducted to prove the effectiveness of the proposed FOI-SSA techniqu
RIS-aided Multi-hop Backhauling for 5G/6G UAV-assisted Access Points, Journal of Telecommunications and Information Technology, 2023, nr 2
Full text linkDrones are considered to be an important part of future 6G telecommunication systems. Thanks to their quick deployment potential, they provide additional connectivity options in the form of a flying hotspot. However, in such use cases, they typically require a wireless backhaul link to facilitate their proper operation, which might be a challenging task in dense urban environments. One of the potential methods that may be relied upon to connect such nodes is the integrated access and backhaul (IAB) approach, where part of the spectrum allocated to users accessing the base station is used for wireless backhauling. Thus, in this work, we consider the problem of establishing a multi-hop wireless backhaul link following the IAB concept, with the aid of drone relay stations (DRSs) and reconfigurable intelligent surfaces (RISs). We formulate the problem of coverage improvement with a fixed number of relays, assuming certain throughput requirements for the backhaul link. The simulations show that the use of RISs offers a coverage improvement in such a scenario or a reduction in the number of nodes involved in ensuring the required backhaul performance