Mobile Radio Systems Research Articles

Resource optimization of multi-UAV assisted communication system based on user scheduling

In order to improve the transmission rate of the multi-user mobile communication downlink wireless transmission system, a resource optimization method for multi-unmanned aerial vehicle (UAV) assisted communication system based on user scheduling and trajectory optimization is proposed. The proposed method establishes an optimization problem with the maximization of the total multi-user throughput as the criterion under the constraints of user scheduling, total energy consumption of UAVs and user service quality requirements. In order to solve this non-convex problem, the original non-convex problem is decomposed into three easy-to-handle non-convex sub-problems by using the block coordinate descent method (BCD). The sub-problems are transformed and solved by introducing slack variables, first-order Taylor expressions, continuous convex approximation (SCA) and other methods, and then alternately iteratively optimized to obtain an approximate suboptimal solution to the original non-convex problem. Simulation results show that the proposed algorithm can effectively improve the total system throughput and has good convergence in both single and multi-UAV communication systems.

Investigating work-related distraction’s impact on male taxi driver safety: A hazard-based duration model

With the increasing use of phone-based ride-hailing apps, concerns have arisen regarding road safety and driver distraction. Despite the recognized safety risks of driver distraction, limited research has explored how distractions from various ride-hailing systems affect drivers in the taxi industry. To close this gap, the current research utilized a driving simulator experiment involving 51 male taxi drivers in two road environments (urban street and motorway) and three distracted driving conditions (no distraction, auditory distraction via radio dispatching system, and visual-manual distraction via mobile application). A car-following scenario with sudden brake events was incorporated into the experiments because this is a typical safety–critical situation where attention will determine the outcome. The collected performance indicators include brake reaction time, time headway, and car-following distance. The grouped random parameters Weibull accelerated failure time model was applied to model the duration data under different road conditions. The brake reaction time and time headway are dependent variables, while the car-following distance is a covariate in the models. The results indicate that although taxi drivers show longer brake reaction time when distracted by mobile app and radio system, this does not necessarily equate with greater risk or reduced safety since they compensate for the risk of rear-end crashes by maintaining a longer time headway. In general, taxi drivers’ brake reaction time and time headway are more profoundly affected by mobile apps when distracted in both urban and motorway scenarios. This highlights the elevated risks associated with such technologies. In addition, significant interaction effects revealed the observed heterogeneity, which suggests that drivers’ personal characteristics influence the relationship between distraction type and driving performance. This research provides valuable insights for designing safer ride-hailing operations and systems.

Wireless channel characterizations in UMi scenarios via ray-tracing at 28 GHz: A perspective of asymmetric beams

As a novel communication pattern, the asymmetric beams adopt a strategy of different beamwidths for a specific link to reduce the beam alignment overheads and energy consumption. A good and thorough knowledge of the radio propagation characteristics is pivotal for further network deployment and optimization of wireless mobile communication systems. In this paper, a multiple-bounce beam channel model is proposed based on the ray-tracing considering the beamforming effects. Besides, a space–time–frequency (STF) power density profile reconstruction method is proposed. Relevant simulations are conducted to emulate an urban micro-cellular (UMi) street scenario at 28 GHz under the case of perfect beam alignment. On this basis, the beam-dependent small-scale fading properties (including STF power density profiles, delay spread, Doppler frequency shift spread, and angular spread) together with the large-scale fading characteristics (involving path loss and shadow fading) are fully investigated. Results reveal that the downlink of asymmetric beams presents more dispersions in contrast to the uplink in the STF domains. Furthermore, the shadow fading variances are asymmetric over different transceivers array element numbers.

Non-orthogonal Multiple Access (NOMA) Channel Estimation for Mobile & PLC-VLC Based Broadband Communication System

Background: The paper focuses on enhancing the performance of 5G wireless mobile communication systems. Furthermore, it addresses the increasing demand for high data rates, improved channel capacity, and spectrum efficiency outlined by the 3rd Generation Partnership Project (3GPP) protocol. Objective: To develop an innovative Non-Orthogonal Multiple Access (NOMA)-based channel estimation (CE) model aimed at improving the performance of 5G wireless mobile communication systems Methods: A proportionate recursive least squares (PRLS) algorithm is utilized for estimating the characteristics of practical Rayleigh fading channels. The applicability of the PRLS algorithm is investigated in Lambertian channels for indoor broadband communication systems such as power line communication (PLC) and visual light communication (VLC) systems. Results: The assessment of evaluation metrics, including mean square error (MSE), bit error rate (BER), spectral efficiency (SE), energy efficiency (EE), capacity, and data rate, have been analysed. Faster convergence and higher accuracy compared to existing state-of-the-art approaches have been demonstrated. Conclusion: The NOMA-based channel estimation model presents significant promise in enhancing the performance of 5G wireless communication systems. The demands for higher data rates and improved spectral efficiency as per 3GPP standards have been addressed.

Digital antenna array based on programmable logic integrated circuits for mobile radio networks

Currently, there is a need to develop new technical solutions for antenna systems for central (base) stations of mobile radio networks, which not only have improved electrical characteristics, but also allow them to adjust from intentional and unintended interference, while providing a reliable communication channel between several correspondents. The purpose of the work is to develop methods for constructing digital antenna arrays with adaptive DN control for VHF mobile radio networks. The presented solution of the ring car allows you to form the DN in the specified directions, to work in multipath mode, as well as the proposed solutions of ring cars can be used both in the center (base) stations of mobile radio communication systems and on mobile objects operating, including in the relay mode.

Design methodology multi-channel antenna systems base stations of professional mobile radio communication with special configurations and types of excitation

Designing base stations of corporate mobile radio communication systems based on the schematic spatial addition of incoherent signals remains an urgent task, since the tactical and technical requirements for antenna-feeder devices are constantly increasing, while the conditions for the placement of antenna systems are usually unique, respectively, the AFD design methodology requires constant improvement. A methodology for designing multi-channel antenna systems of base stations for professional mobile radio communications with special configurations and types of excitation was developed. The work provides examples of analytical and practical application of the developed methodology.

Mathematical model of single-channel search for signals of mobile radio communications with one degree of detection in the frequency-time domain.

In the context of a full-scale invasion and military operations for Ukraine's independence, the issues of radio monitoring of radio emission sources of telecommunication networks and systems are gaining special attention and require fundamentally new approaches to the level of informatization, technical implementation and increase of their efficiency. Today, the technical means of radio interception, monitoring and direction finding in the networks of mobile radio communication systems are realized in the form of software and hardware complexes, the most important performance indicators of which are considered to be speed, accuracy of detection and probability of recognition of mobile radio communication means with their information content. At the same time, these issues still remain problematic and require further development of methods and techniques for searching and detecting signals of mobile radio communications in both frequency and time telecommunication channels and their information processing. To solve this issue, the authors propose a mathematical model for searching for mobile radio signals in the frequency-time domain with one degree of detection. The description of the mathematical model for determining the spectral components of signals in the frequency and time domains is carried out using the basic provisions of the theory of directed probability graphs, geometric probabilities with its well-known problem of meeting in a given time interval, and the theoretical foundations of statistical information processing. The analysis of the proposed model shows that the probability of successful completion of the search for a signal with one degree of detection in the frequency-time domain for a given time depends on the value of the signal duration, the number of analyzed frequency channels, the time of signal analysis in each channel, and the probabilities of errors of the first and second kinds The article presents the results of calculations of the value of the probability of successful completion of the signal search as a function of the search time at different values of the analysis time. It is shown that the application of the mathematical model of single-channel search for signals of mobile radio communication means with one degree of detection in the frequency-time domain in practice will make it possible to determine the quality of the radio monitoring process and increase the efficiency of evaluating the spectral components of radio signals in terms of speed, detection accuracy and probability of recognition of mobile radio communication means with further determination of their information content.

Модели расчета распределения уровня мощности электромагнитного поля в системах подвижной радиосвязи для малых дистанций в летний период

The statement is substantiated that for the design of mobile radio communication systems at short distances up to 1 000 m, the main recommended calculation models have a significant error, since they were created for calcula-tions of long distances (as a rule, from 1 to 50 km) and have limitations in application. Due to the fact that at the present stage of development of mobile radio communication systems, the frequency ranges are in intensive research and use not only 900 and 1 800 MHz, but also 450-800 MHz sections, as well as from 2 100 to 6 000 MHz, which were not previously used for cellular communication systems, it is necessary to propose additional models necessary for the preliminary design of 3-5 generation systems in the range from 2 100 MHz. The range of radio waves in the ranges from 2 100 to 6 000 MHz is significantly reduced compared to the ranges of 1 800 or 900 MHz. The use of classical calculation models such as the Okumura and COST-231–Hata models at distances less than 1 km is characterized by significant errors and is not recommended by the authors of the models themselves for use at short distances. To solve this problem, new models have been developed for calculating the attenuation of radio signals designed to estimate attenuation at short distances.

WIRELESS TRANSMITTER FOR OPTICAL COMMUNICATION WITH FREQUENCY-MODULATED LASER CARRIER

Interest in the use of unguided optical systems is growing, due to the development of wireless mobile and indoor communication systems as well as the applications of lasers in space technology. The proposed laser transmitter, with frequency-modulated carrier, represents the optical transmitter of a wireless optical communication system, for transmitting audio signals on laser carriers, which can be used both inside buildings and outside, for distances estimated according to system parameters. In the paper are presented elements of design of the electrical diagram of principle, as well as analysis by SPICE simulation of the designed circuit. The results obtained by SPICE simulation synthesize the operation of the laser transmitter, allowing an optimization of the parameters of the component circuits.

Wireless mobile communication systems: current status, application fields and challenges

The article analyzes the current state of mobile communication systems, and highlights development perspectives from the past to the present, vulnerabilities in security systems and application fields. At the same time, it provides information about the possible threats that may occur during an attack on the data entering the network from intelligent devices. For many years, numerous research centers have been conducting intensive research on the direct communication between various devices through mobile communication systems. These studies are realized to manage mobile communication systems and computers, mobile devices and other equipment. Therefore, special attention is paid to the development of mobile communication systems both in Azerbaijan and in the world, and it is considered one of the most promising fields of application of information technologies. The article also provides information about the fifth-generation mobile communication system, which is a new generation of wireless network technology for digital mobile networks. The results of research conducted on the fifth-generation mobile communication system in the world and the technological innovations to be brought to the healthcare and energy fields, agriculture, smart cities, smart villages and transport sectors are reported.

Misurata Rural Area Path Loss Propagation Prediction and Optimization Using Machine Learning Techniques

Path loss prediction is of great importance in studies of designing, developing, and improving the performance of wireless networks and mobile communication systems of the 5G which requires of accuracy in performance and reduction in losses. Therefore, new models should be proposed to predict path loss propagation with high accuracy and less complexity. In this paper, a path loss model was designed and implemented using artificial intelligence and machine learning techniques, which training and testing on a real database created based on maximum measured distance and received power from the base station in a GSM system operating in 900 MHz band, in a rural environment, Misurata, Libya. Traditional methods like the "simple path loss model" performed poorly, with an average error of 5.87. In contrast, modern models based on artificial intelligence (AI) like GRNN, Fitnet, and Feedforward Net achieved significantly lower errors, ranging from 0.26 to 1.35. Furthermore, the AI models showed a strong correlation between the predicted and actual signal strengths (correlation coefficient R reaching 0.9962 for Fitnet and 0.99399 for Feedforward Net). This indicates highly specific and reliable predictions. Keywords: wireless communications, propagation loss prediction, ANN, machine learning, GRNN, urban area

Deep Learning-Based SC-FDMA Channel Equalization

It is very challenging to design an effective wireless communication system. That’s because of numerous factors affecting the performance of a typical wireless communication system, such as nonlinear channel distortions and impairments. single carrier frequency division multiple access (SC-FDMA) is a multiple access scheme that is an important part of the long-term evolution (LTE) standard for uplink transmission. An advanced mobile radio system’s multiple access schemes should indeed meet stringent requirements, such as a low bit error rate (BER). In this article, we investigate the equalization problem for nonlinear channel distortions and impairments using deep neural networks (NN). We introduce a novel combined deep neural network channel equalization and symbol detection scheme based on a deep learning (DL) recurrent feedback (RF) long short-term memory (LSTM) neural network to achieve blind equalization and decoding for SC-FDMA systems without knowing the channel state information (CSI). To train the model efficiently, the training data is gathered by simulation, with channel effects and noise treated as a complete black box. CSI and constellation demapping are learned by a deep neural network (DNN) model. Then, the frequency-domain sequences that have been corrupted are implicitly equalized to get the broadcasted signal back. Our specified SC-FDMA system, which uses a quadrature phase-shift keying (QPSK) modulation method and the suggested Deep Learning-based model channel equalizer, performs better than the existing equalizers by an average of 1 to 4 dB at moderate signal-to-noise (SNR) ratios, according to simulation data. A complexity comparison between the proposed and the conventional equalizers was conducted in terms of training time, execution time, and number of operations. On combined channel equalization and symbol detection, the suggested system delivers state-of-the-art performance.

Achievable Spectral Efficiency of Line-of-Sight MIMO Fixed Links with Compact Planar Antenna Arrays and Power Amplifier Limitations

Fixed Point-to-Point microwave wireless systems with high spectral efficiency are needed to meet the pervasive and increasing demand for capacity in back-haul networks of mobile radio systems. In this context, spatially multiplexed LoS-MIMO (Line-of-Sight Multiple Input Multiple Output) systems have been studied for about twenty years, particularly in the millimeter wave frequency bands (above 15 GHz). However, their deployment in real networks has been really limited, to the authors’ knowledge. This has been due to several factors, i.e. the practical possibility of using extremely high-level modulation formats (nowadays up to 8192-QAM), the joint use of co-channel dual polarization, and the availability of wider channel bands in the new high frequency ranges (e.g. E-Band). In addition, a crucial reason has been the difficulty of installing multiple antennas spaced apart in order to maximize the MIMO spatial multiplexing so providing the maximum capacity gain. This optimal antenna separation, even for the classical MIMO M×N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M \ imes N$$\\end{document} with M = 2 antennas at the receiver and N = 2 antennas at the transmitter, can be several meters, e.g. 5.71 m at 23 GHz on a 5 km link. In this article, we analyze the performance of LoS-MIMO systems where antenna separation is highly sub-optimal, for limiting the array size, and a satisfactory performance is made possible by the exploitation of specific bit loading and power allocation strategies and the setting of the working region of the RF transmitter power amplifiers to operate at a given Signal-to-Inter Modulation Distortion Ratio (SIMDR). The result is an overview of the advantages and drawbacks of compact LoS-MIMO from a wider perspective than in the existing literature, including fundamental aspects for the practical implementation of these systems. Performance is discussed in many cases of interest and compared with the state of the art SISO (Single Input Single Output) system.

Wireless data transmission in the 560-GHz band utilizing terahertz wave generated through photomixing of a pair of distributed feedback lasers injection-locking to a Kerr micro-resonator soliton comb

The increasing demand for higher data rates in 6G mobile wireless systems has sparked a keen interest in terahertz (THz) waves as a high-frequency, high-bandwidth carrier. This study presents a novel approach to wireless data transmission at 560 GHz, leveraging the use of THz waves generated through the injection-locking of a pair of distributed feedback lasers into a Kerr micro-resonator soliton comb. Experimental results demonstrate a Q-factor of 6.23 in 1-Gbit/s on-off-keying data transmission, which closely approaches the error-free limit represented by a Q-factor of 6.36. Additionally, the study achieves low error vector magnitudes for various modulation formats: 23.9% for 1-GBaud binary-phase-shift-keying, 23.6% for 1-GBaud quadrature-phase-shift-keying, and 8.07% for 0.1-GBaud 16-quadrature-amplitude modulation. This innovative approach holds promise for achieving high-quality, high-speed wireless data transmission, thereby advancing THz communication technology for integration into 6G systems.

Performance enhancement of 5G uplink MIMO over fading-shadowing, path losses, and ISI using LZF equalize

The challenges of the 5G mobile wireless communication systems transmission channels have been changed continuously because of the signal transfer path characteristics such as real-time applications, path loss, multiple users, reflected rays, channel Rayleigh-fading, shadowing, noise, and inter symbol interference (ISI). These challenges have been treated to reach the minimum bit error rate (BER) value of the received data and maximum data rate of high-speed wireless mobile communication systems. In this paper, the linear zero-forcing (LZF) equalizer with uplink multi-input multi-output (MIMO) system has been proposed to enhancement the BER, which is caused by the ISI, Rayleigh fading, shadowing, path losses, and additive white gaussian noise (AWGN). Furthermore, the proposed approach is applied to a different number of antennas constellation to show the effect of increasing the number of antennas on the BER. The results show that the proposed LZF equalizer-MIMO system model has reached lower BER values, and high performance with an increase in the receiver to 8×14, 8×16 and 8×18 antennas constellation at 8, 10, 12, 14, 16, and 18 dB signal to noise ratio (SNR).

Development of a modified propagation model of a wireless mobile communication system in a 4G network

<span lang="EN-US">Pathloss is a key element that causes signal deterioration in the channel as the signal power reduces inversely with propagation distance, this deterioration experienced by the channel is majorly as a result of reflection, absorption, and scattering of the signal. This study however takes into consideration the radio path loss for precise base station (BS), frequency, and power adjustment prediction evaluated over a frequency of 2.3 GHz. With a distance range between 0.1 and 1.5 km for collection of data on the measured received signal strength (MRSS), five empirical models and a modified model were used to validate the measured data to determine their suitability for pathloss prediction at Federal University of Technology, Owerri (FUTO), Imo state, Nigeria. The results shows that the root mean square error (RMSE) for the Okumura-Hata, COST 231-Hata, Ericsson model, Lee, Stanford University Interim (SUI), ECC-33, and modified models are 14.33, 9.73, 25.79, 48.4, 33.76, and 8.31 dB respectively. Additionally, the Ericsson model provided 0.498 dB, the COST 231-Hata recorded 0.733 dB, and the modified model provided 0.453 dB for mean absolute percentage error (MAPE). Therefore, the improved model produces the best results, consequently, be deployed to approximately predict path loss for mobile radio coverage in Owerri, Nigeria.</span>

An intelligent Espionage Robot Controlled by Mobile Wireless System

The field of robotics has grown exponentially as a result of the integration of several domains. With advances in technology, a drone, also known as an unmanned aerial vehicle (UAV), can be controlled from 20,000 miles away. Such technologies either use artificial intelligence or radio communication to control their process. Creating one such autonomous robot is the main task. More than a thousand kilometers away, in a distant place, this must be managed. Currently available technologies can only control robots up to 500 yards away. Our communication way is WIFI. These Wi-Fi-connected computers send serial data, and they also communicate with a system using a microcontroller to direct how it operates. The robot senses as well in order to avoid obstacles and determine its location.

Measurement and Investigation of HB-UWB Transmission Link for BAN System

The short-range wireless multimedia is consider used a ultra wideband (UWB) technology for human body mobile and multimedia applications shows promise for wireless multi-media systems. Based on IEEE 802.15.6, wireless body area networks (BAN) require understanding the human body’s effects on channel characteristics. This paper presents how to evaluation of human body ulra-wideband (HB-UWB) transmission with line-of-sight and non-line-of-sight scenario. Our research aims to enhance HB-UWB channel propagation on the body media by employing with CLEAN algorithm to eliminate noise. This research leverage findings from previous studies to facilitate performance comparison. Furthermore, for analyze system performance using the CLEAN algorithm at different body positions. The measurement setup covers band the FCC regulated from 3.0 GHz to 11 GHz. It includes the tested with wideband antenna and vector network analyzer (VNA). HB-UWB characteristics are shows in the path loss and power delay profile are discussed as relevant parameters. This research very useful for design and evaluation of human body mobile network and wireless multimedia systems.

Frequency allocation algorithm

Wireless communication technology's quick advancement has facilitated the ongoing formation of numerous new communication business scenarios and the thorough connectivity of man-machine-object-space. The conflict between few channel resources and high demand is becoming more and more obvious, which adds to the stress on the entire network. In order to enhance communication quality with constrained frequency resources, more optimal channel allocation techniques are urgently required. This paper discusses the increasing demand for frequency resources due to the exponential growth of data traffic, which has necessitated more efficient channel allocation methods to optimize communication quality with limited frequency resources. The evolution of mobile wireless cellular communication systems from the first generation to the current fifth generation, and the imminent emergence of the sixth generation, are also discussed. The paper highlights the importance of ultra-dense networks and device-to-device communication in meeting the capacity and coverage requirements of 5G networks. The advantages and disadvantages of different frequency reuse methods, specifically Fractional Frequency Reuse (FFR) and water injection algorithm, are analyzed. The paper summarizes these methods' principles and application effects in specific situations, emphasizing the need for appropriate frequency reuse methods to achieve optimal channel allocation and communication quality.

Exploring the Application of Design Thinking Methodology in Cellular Communications Network Planning and Deployment

Cellular network planning and deployment represent a set of activities that operators have been performing since the advent of mobile wireless communication systems. Decisions along this route traditionally have been based on engineering or commercial criteria, focusing on providing the best service to users. Although operator companies gather information regarding perceived quality of service among their subscribers, mainly using surveys, engineers work with numerical data more than with people’s interests, feelings, perceptions, or hopes. In other sectors, Design Thinking has arisen as a methodology that allows designers to involve real-world users in implementing new products or services. Thus, we are introducing this methodology for cellular networking, exploring its application in a process that could be designed in a more human-centered way. With this aim, we analyzed the different steps that could be included in the network planning and deployment. From this analysis, we detected which actions have chances to be explored in a human-centered view and thus, can be improved with some Design Thinking tips. Finally, we developed an experience of limited potential, comparing the insights obtained by an empathic interview to those given by traditional surveys, to show what Design Thinking could provide.