Orthogonal time frequency space (OTFS) modulation is introduced as a modulation technique known for its strong performance in high-Doppler scenarios. This two-dimensional modulation method involves multiplexing information symbols in the delay-Doppler (DD) domain. This study presents a deep learning (DL) based signal detection for OTFS non-orthogonal multiple access (NOMA) communication networks. In thiswork, theOTFS known as a popular sixth-generation (6G) candidate solution with enhanced spectral efficiency in high-mobility environments, is combined with NOMA over Rayleigh fading channels. In addition, a DL-based signal detection approach for the OTFS-NOMA scheme is proposed, where the network is trained to distinguish and decode the signals effectively. This enhances the overall system performance and paves the way for more efficient and reliable communication in high-mobility wireless environments. In our study, signal recovery employs a bidirectional long short-term memory (BiLSTM) network. The comparison of the message passing (MP) algorithm and the BiLSTM technique regarding symbol error rate (SER) performance for detecting signals over near and far users is evaluated. Furthermore, we examine the impact of the three common optimizers on the SER achievement for training optimizer selection. Moreover, the numerical results show that the root mean squared propagation (RMSprop) outperforms the other optimizer selection techniques regarding SER. Finally, the performance of the BiLSTM technique is observed to be better than that of the MP, except for the stochastic gradient descent (SGD) optimizer. RMSprop and the adaptive momentum optimizer (Adam) yield a maximum training accuracy of 99.9%.

This paper gives a theoretical evaluation on how feeder lengths are appropriate for distinct conductor materials using rectangular microstrip patch antenna shape with the help of finite integration techniques (FIT). In this study, the ground surface width is 5.6mm and the ground surface length is 4.65 mm for the rectangular microstrip patch antenna. The length of the patch is 3.44 mm while the patch width is 4.40 mm. The substrate thickness is at 0.20 mm, the patch thickness is 0.035 mm the additional inner feed length is 1.05 mm and the microstrip line feed width is 0.6 mm. Antenna of rectangular microstrip patch type has been designed to work in the 20 – 36 frequency band and working frequency of the proposed antenna is 28 GHz. Compared to the use of a single conductor on the surface of the designed patch antenna, three different conductor materials-copper, gold, and aluminum-were applied to the patch surface of the antenna. The return loss (S11), voltage standing wave ratio (VSWR), bandwidth (BW), directivity and gain of the microstrip antenna parameters are studied using finite integration method Computer Simulation Technology (CST) based on nine different feed lengths in microstrip antenna design. When analyzing the feature of the simulation, the optimal S11 can be observed at the 28 resonant frequencies in the copper conductor. According to the analysis results, for copper conductor the best S11 was obtained at a resonant frequency of 28.03 GHz. The value of S11 is -31.19 dB and the BW value is 968 MHz. For the gold conductor the high return loss is achieved using the at the resonated frequency of 28.01 GHz. S11 value is -32 dB and the BW value is 972 MHz Aluminum conductor has the highest value of S11 with a resonant frequency of 28.01 GHz as shown in -33.29 dB and BW value is 976 MHz. Unsurprisingly, the characterization of the conductor deposition on each structure shows that aluminum conductor yielded the best S11 among all the conductor types. The VSWR is equal to 1.05 for copper conductor at resonant frequency of 28.03 GHz, 1.05 at gold conductor at a resonant frequency of 28.01 and 1.04 for aluminum conductor at a resonant frequency of 28.01 GHz. The maximum directivity values that have been attained in the three-dimensional (3D) representation of the copper conductor, gold and aluminum conductor antennas are nearly 6.99 dBi, respectively. The maximum values of the gain are obtained for the 3D representation of copper, gold and aluminum conductor antennas are 6.61, 6.60 and 6.58 dBi, respectively.

Orthogonal Time Frequency Space (OTFS) is a promising approach which is widely employed in sixth generation (6G) wireless network systems. Because of its superior performance in high-mobility environments, OTFS modulation has received a lot of attention lately. Due to OTFS modulation works in the delay-Doppler (DD) domain rather than the conventional time-frequency (TF) domain, it works effectively in such circumstances. The idea of non-orthogonal multiple access (NOMA) is integrated into OTFS as an important approach to improve the spectral efficiency (SE) to investigate the efficiency potential and performance. In this research, we study OTFS modulated NOMA system for two destination users in the high mobility environment. The message passing detection algorithm is utilized to examine bit error rate (BER) performance for both near and far users in the proposed OTFS modulated NOMA system. The BER simulation results demonstrate that the power allocation (PA) coefficient, delays, and Doppler effects significantly impact the performance of the system.

LoRa (Long Range) teknolojisi, düşük güç tüketimiyle uzun mesafelere veri iletme yeteneği sunarak Nesnelerin İnterneti (IoT) uygulamalarına önemli katkılar sağlamaktadır. Düşük Güç Geniş Alan Ağı (LPWAN) tabanlı protokoller, IoT cihazları arasında küçük veri paketlerinin uzun mesafelerde iletimini mümkün kılmaktadır. LoRa, coğrafi engeller, doğal afetler veya insan kaynaklı kesintiler gibi olağanüstü durumlarda, kısa menzilli radyo iletişim sistemlerinin yetersiz kaldığı bölgelerde kritik bir iletişim aracı olarak öne çıkmaktadır. Bu çalışmada, Akıllı Ulaşım Sistemleri’nin (AUS) kesintisiz işleyişini desteklemek amacıyla, düşük güç tüketimiyle uzun mesafeli veri iletimi sağlayan LoRa teknolojisinin uygulanabilirliği incelenmiştir. 3.000 metrelik menzile kadar sağlanan iletişimle, model uydu üzerindeki aviyonik sistem sensörlerinden elde edilen veriler, LoRa modülleri aracılığıyla yer istasyonuna başarılı bir şekilde iletilmiştir. Buna ek olarak, model uydu üzerinde yer alan kamera sistemi üzerinden gerçek zamanlı görüntü aktarımı yapılmıştır. Sonuçlar, 700-600 metre aralığında irtifa ve 3.000 metre menzile kadar yapılan saha testleriyle, LoRa teknolojisinin düşük maliyetli uydularla kesintisiz veri iletimi ve sistem sürekliliği için uygun bir çözüm sunduğunu göstermektedir.

Background. Server horizontal load balancing is a crucial aspect of modern computing systems, particularly in cloud computing environments. The efficient management of incoming flows of applications is essential to ensure optimal resource utilization and minimize energy consumption. This study focuses on developing a method for managing the incoming flow of applications to reduce energy consumption in server horizontal load balancing. Objective. The primary objective is to develop a method for managing the incoming flow of applications to reduce energy consumption in server horizontal load balancing. This involves identifying the maximum permissible number of applications that can simultaneously enter the system for service, ensuring that the volume of resources used is close to the total maximum possible amount of resources. The method aims to minimize the variance of the elements of the sequence of maximum allowable numbers of applications and the dispersion of the elements of the sequences of volumes of resources used. Methods. The method involves several key steps: Input Load Smoothing Scheme: A static control method is proposed to smooth the incoming load. This involves developing a scheme for smoothing the incoming load, which is a set of values of the maximum allowable number of requests (sequence {ki}) arriving at the system input for a small time interval ∆ti. The sequence is selected to ensure that the volume of resources used is close to the total maximum possible amount of resources. Genetic Algorithm: The selection of the sequence {ki} is carried out using a genetic algorithm. The algorithm involves crossover, mutation, and selection operations to minimize the variance of the elements of the sequence and the dispersion of the elements of the sequences of volumes of resources used. Resource Allocation: The method involves allocating resources for the maintenance of a given type of service. The parameters of the server, which are characterized as the resources of the system serving the applications, are usually calculated for the average values of the parameters of the input stream. Delay Introduction: To manage the application processing process and prevent resource shortages, a delay is introduced for a part of the applications that coincide with a surge in load. The delay time is determined so that delayed applications do not enter the system until the previous burst of load is successfully serviced in the resource-consuming functional block. Results. The results of the study include the development of a method for managing the incoming flow of applications to reduce energy consumption in server horizontal load balancing. The method involves the use of a genetic algorithm to select the sequence {ki} that minimizes the variance of the elements of the sequence and the dispersion of the elements of the sequences of volumes of resources used. Conclusions. The study concludes that the proposed method for managing the incoming flow of applications can effectively reduce energy consumption in server horizontal load balancing. The method involves the use of a genetic algorithm to select the sequence {ki} that ensures efficient use of system resources and minimizes the variance of the elements of the sequence and the dispersion of the elements of the sequences of volumes of resources used. The method can be applied in various scenarios where efficient use of system resources is crucial, such as in cloud computing environments.

Background. The usage of IoT technologies leads to the social, technological and financial development of society. While complex systems play an important role in the IoT, the design, integration and use of simple devices really drive the technology's widespread adoption. At the same time, ensuring a high level of security for simple IoT devices is a difficult task. The reasons for this are device limited computing resources and low power consumption requirements. It prevents the implementation of most modern cryptographic protocols for simple IoT devices. From a security point of view, the most critical communication stage is device pairing, when shared encryption keys are formed to establish a secure communication channel. Objective. The purpose of the paper is to analyse the main vulnerabilities of a simple IoT device pairing process and develop a method for improving security of this process. The method should provide proximity-based device authentication and pairing process protection against known attacks, such as man-in-the-middle attack. Methods. The method of pairing process security improvement includes proximity-based device authentication using analysis of the wireless signal strength. The security of the authentication method is proven analytically and by results of practical experiments with measurement of wireless signal strength change with distance and obstacles between devices. Results. Performed research demonstrated that the proposed method guarantees secure user authentication at a close distance between devices and protection against attacker located at least 10 meters from the paired device. Provided theoretical calculations and experimental results show that the level of attacker's wireless signal power increase required for a successful attack exceeds technical capabilities of existing communication devices. Conclusions. The article solves an important issue of improving the security of simple device pairing. The proposed method of proximity-based IoT device authentication provides pairing process protection against man-in-the-middle attacks. Mathematical calculations were confirmed by conducting a number of experiments to research wireless signal power change depending on the distance and types of obstacles between devices. The proposed authentication method can be integrated into the existing JustWorks protocol for connecting simple IoT devices using the BLE communication channel.