Wireless Communication Services Research Articles

Design of a novel compact low specific absorption rate multiple input multiple output antenna for 5G sub-6 GHz terminals

This investigation presents a new design and analysis of a fourteen elements massive multiple input multiple output (MIMO) compact low specific absorption rate (SAR) antenna system for 5G and beyond terminals. The MIMO antennas are realized for sub-6 GHz LTE-band 46 (5.1-5.8 GHz) long-term evolution 5G wireless communication services. The proposed antenna system is designed on an FR-4 dielectric constant 4.3 substrate consisting of the main board and four sideboards. The radiating elements are developed on the sideboards consisting of a monopole antenna and two metamaterial unit cells, as well as the feed line is designed on the principal board. The overall volume of the proposed structure is 150×80×7.5 mm. Through the use of the metamaterial unit cells, the proposed antennas have been arranged in close proximity without developing a strong mutual coupling. The results obtained were very important in terms of impedance matching, isolation among the antennas, and good gain. Even, the SAR analysis at the operating frequency band of 5.5 GHz proves that the proposed MIMO antenna system satisfies safety standards set for human exposure at the international level. Therefore, the proposed massive MIMO antenna structure is a potential solution for future communication applications.

Energy-Efficient Resource Optimization for IRS-Assisted VLC-Enabled Offshore Communication System

In this paper, a downlink energy efficiency maximization problem is investigated in an intelligent reflective surface (IRS)-assisted visible light communication system. In order to extend wireless communication coverage of the onshore base station, an IRS mounted on a unmanned aerial vehicle (UAV) is introduced to assist an onshore lighthouse with simultaneously providing remote ship users wireless communication services and illumination. Aiming to maximizing the energy efficiency of the proposed system, a resource allocation problem is formulated as the ratio of the achievable system sum rate to the total power consumption under the constraints of the user’s data requirement and transmit power budget. Due to the non-convexity of the proposed problem, the Dinkelbach method and mean-square error (MSE) method are adopted to turn the non-convex origin problem into two equivalent problems, namely transmit beamforming and reflected phase shifting. The Lagrangian method and semidefinite relaxation technique are used to obtain the closed-form solutions of these two subproblems. Accordingly, an alternative optimization-based resource allocation scheme is proposed to obtain the optimal system energy efficiency. The simulation results show that the proposed scheme performs better in terms of energy efficiency over benchmark schemes.

Citizens’ Perceptions and Assessment of an Urban Mountainous Forest Restoration: Nature, History, and Changes

Background and objective: Most cities in South Korea have mountainous forests as hinterland green space in their centers, which are used as urban parks. This study was conducted to analyze citizens' perceptions of a mountainous forest restoration project being carried out in Jinju City.Methods: The research site is part of Bibongsan Mountain in Jinju City. Visitors' perceptions of the Bibongsan Restoration Project (BRP), carried out since 2015, were surveyed and analyzed regarding nature, history, and changes. The survey was conducted from August to October 2019, and the collected data were statistically analyzed.Results: The main socio-demographic changes were an increase in the proportion of men among visitors, aging, and an increase of unemployed people in the occupational distribution. The overall assessment of BRP implementation was positive. Visitor perceptions of the value, revival, and restoration of historical resources were more vital than in 2015 and had a strong positive correlation with each other. Visitors identified a high need for safety facilities for elderly visitors, improved wireless communication services, facilities for various recreational activities, outdoor learning facilities and programs for nature study, expanded parking lots, and improved transportation services.Conclusion: The urban mountainous forest restoration project is overall satisfactory and needs to be continued. The results showed that urban mountainous forests are not only recognized as spaces for walking and exercise for health but also recently as historical spaces expressing the unique or featured identity of the city, educational spaces for interest and understanding of nature, and recreational spaces that reflect local lifestyle changes. Thus, urban forests need to be restored in the context of local historical and cultural resources as well as natural resources. In addition, there is a need to be aware of various changes in the population, including aging and an increase in retirees.

Study of Consumer Behaviour Towards Reliance Jio

The main objective of this project is to study the awareness of Reliance Jio amongst the customers compared to other telecom service providers. The satisfaction of customers is very important and with various products and services offered by the company its customers seem to be meaningless if it‟s not beneficiary to the customer from their end, so the second objective of this research is to study the customer satisfaction level of customers towards Reliance Jio and its services. To achieve success in long run a company needs a thorough study of its SWOT analysis (Strength, Weakness, Opportunities, and Threats). So the third objective of this research is to find the market potential and market penetration of Reliance Jio products and services. Reliance JioInfocomm Limited (Commonly called RJIL) is an Indian Internet access (commonly called „Broadband‟) and telecommunications company headquartered in Mumbai India‟s largest private sector company, is the first telecom operator to hold pan India Unified License. Reliance Jio is setting up a pan India telecom infrastructure to provide fourth generation LTE TDD high speed wireless internet and mobile communication services which was then launched in June 2015. Reliance Jio was founded in 2010 by MukeshAmbani. Reliance Jio offers mobile telephony and wireless broadband. Parent company of Reliance Jio is Reliance Industries and its subsidiary is LYF. To study the objectives discussed two types of sources were used to collect the data: - Primary and Secondary data. Primary data is also called as „First-hand data‟ or „Raw data‟. The primary data primarily means the unfiltered raw data collected by the researcher in the research process. In this project for the primary data a sample of 40 people were surveyed.

Defending dominant cooperative probabilistic attack in CRNs by JS-divergence-based improved reputation algorithm

Rapid advances in wireless communication services has made limited spectrum resources increasingly scarce. One promising solution for enhancing spectrum utilization is cooperative spectrum sensing (CSS) in cognitive radio networks (CRNs). However CSS is vulnerable to Byzantine attack. Current researches show that Byzantine attack is easily defended for their fixed attack probability. In this context, we propose an improved attack model called the dominated cooperative probabilistic attack (DCPA) model in the actual situation, building upon the generalized collaborative probabilistic Byzantine attack model. This DCPA model contains auxiliary cooperative attackers (ACAs) who launch attacks and a dominant attacker (DA) who determines ACAs’ attack probability intervals based on their respective credibility. The DCPA model allows ACAs to flexibly launch attacks, without being identified by the traditional reputation defense algorithm, significantly compromising the sensing performance of CSS. To successfully resist the threat posed by the DCPA model to CSS, we propose a JS-divergence-based improved reputation algorithm that can distinguish honest users (HUs) from attackers. This algorithm analyzes two consecutive sensing reports to identify differences in sensing behavior between HUs and attackers. Through Python simulation analysis, we demonstrate that, compared to the generalized cooperative probabilistic attack (CPA) model and the attack-free CSS (AFC) model, the proposed DCPA model is more concealed and significantly more disruptive to the performance of traditional reputation defense algorithms. Furthermore, our approach greatly enhances the performance of CSS by promoting the participation of HUs and suppressing attackers during the final data fusion. And also compared with the PAM2 algorithm, the conventional voting rule (CVR) algorithm and the traditional reputation defense algorithm, our proposed algorithm improves the detection performance by at least 7%, 15% and 50%.

Energy‐efficient hybrid beamforming for millimeter‐wave‐based massive multiple‐input multiple‐output system

SummaryThe advanced wireless communication system requires abridged energy consumption, enhanced data rate, and good signal coverage. The massive MIMO technology for 5G systems has been developed to accommodate several users simultaneously with superior throughput. The claim for high data rate wireless communication services is expanding quickly as time goes. Thus, the key difficulty is that as the number of users grows, the number of phase shifters grows as well, causing the system to consume more power; as a result, the system's energy efficiency decreases. Hybrid beamforming has recently emerged as an attractive technique for millimeter‐wave (mmWave) communication systems. The analog beamformer in the RF domain and digital beamformer in the baseband are coupled through a minimal number of RF chains in hybrid beamforming architecture. Hybrid beamforming utilizes fewer RF (radio frequency) chains than the total number of antennas to have a lower energy consumption design. The hybrid beamforming for a mmWave‐based massive MIMO system through different phase shifter selection mechanisms is proposed to achieve the highest energy efficiency for mmWave communications systems. The fully connected with phase shifter selection, sub‐connected with phase shifter selection (SPSS), and fully connected and sub‐connected with phase shifter selection with halved and doubled switches are considered for this research. The simulation results show the SPSS with halved switch outperforms on energy efficiency.

An Imbalanced Sequence Feature Extraction Approach for the Detection of LTE-R Cells with Degraded Communication Performance

Within the Shuo Huang Railway Company (Suning, China ) the long-term evolution for railways (LTE-R) network carries core wireless communication services for trains. The communication performance of LTE-R cells directly affects the operational safety of the trains. Therefore, this paper proposes a novel detection method for LTE-R cells with degraded communication performance. Considering that the number of LTE-R cells with degraded communication performance and that of normal cells are extremely imbalanced and that the communication performance indicator data for each cell are sequence data, we propose a feature extraction neural network structure for imbalanced sequences, based on shapelet transformation and a convolutional neural network (CNN). Then, to train the network, we set the optimization objective based on the Fisher criterion. Finally, using a two-stage training method, we obtain a neural network model that can distinguish LTE-R cells with degraded communication performance from normal cells at the feature level. Experiments on a real-world dataset show that the proposed method can realize the accurate detection of LTE-R cells with degraded communication performance and has high practical application value.

Coordinate Interleaved OFDM With Repeated In-Phase/Quadrature Index Modulation

Orthogonal frequency division multiplexing with index modulation (OFDM-IM), which transmits information bits through ordinary constellation symbols and indices of active subcarriers, is a promising multicarrier transmission scheme and has attracted the attention of researchers due to numerous benefits such as flexibility and simplicity. Nonetheless, OFDM-IM cannot satisfy the needs of future wireless communication services such as superior reliability, high data rates, and low complexity. In this article, we propose a novel OFDM-IM scheme named coordinate interleaved OFDM with repeated in-phase/quadrature IM (CI-OFDM-RIQIM), which provides superior error performance and enhanced spectral efficiency due to its diversity order of two and clever subcarrier activation pattern (SAP) detection mechanism, respectively. In addition, CI-OFDM-RIQIM is further extended to coordinate interleaved OFDM with in-phase/quadrature IM (CI-OFDM-IQIM) by doubling information bits transmitted by IM. Furthermore, log-likelihood ratio (LLR) based low-complexity detectors are designed for both proposed schemes. Theoretical analyses are performed and an upper bound on the bit error probability is derived. Comprehensive computer simulations under perfect and imperfect channel state information (CSI), are conducted to compare the proposed and reference schemes. It is shown that CI-OFDM-RIQIM and CI-OFDM-IQIM show superior results and can be considered promising candidates for next-generation wireless communication systems.

Key security measurement method of authentication based on mobile edge computing in urban rail transit communication network

In the rail transit industry, the communication network is also widely used in various professions. Rail transit stations have the characteristics of narrow space, high degree of airtightness, limited sight lines, and uneven distribution of personnel in various periods. Although the security degree of rail transit entrances and exits is relatively reliable compared with that of stations, the anti-risk ability is fragile, and the consequences are often disastrous. To solve the problems of low-security access rate, long response time and ineffective identification of attack components of urban rail transit communication platform users, a security measurement method based on mobile edge computing (MEC) for the authentication key of urban rail transit communication network is proposed. Firstly, the wireless communication service of the urban rail transit platform is analyzed, and the data key protocol is constructed to obtain the hyper-chaos key pair of wireless communication information. Then, the double chaotic mapping model is applied to determine the key form and input parameters, and the bit key stream is obtained, which is subjected to exclusive operation with the plaintext for key decryption. Next, the block matching structure is used to analyze the associated eigenvalues that affect the security risk of urban rail transit communication networks. Meanwhile, the MEC server is used to accelerate the extraction of its feature values. Finally, in the environment of MEC, the paper constructs a risk identification model, evaluates the security strength of the authentication key, controls the threshold value, analyzes the impact factors and weights of communication network security, and completes the traceability measurement of communication network security risk. Experimental results show that the security access times of the MEC platform are senior, the maximum attack component obtained is 23500, which is consistent with the actual value, and the global maximum response time is 0.30 ms.

Smart sensing enabled dynamic spectrum management for cognitive radio networks

Cognitive Radio Networks (CRNs) have ushered in a transformative era in wireless communication, reshaping the landscape of radio spectrum utilization and management. At the core of CRNs lies the pivotal capability to sense the radio frequency spectrum dynamically and adapt transmission parameters to preemptively address interference and optimize spectrum utilization. This article addresses the escalating challenges associated with Quality of Service (QoS) management in CRNs, exacerbated by their dynamic nature, especially in scenarios characterized by high mobility. Concurrently, the article underscores the critical significance of energy efficiency, given its direct implications on network operational costs and sustainability. To effectively navigate the intricate interplay between QoS and energy management in CRNs, we propose a Smart Sensing Enabled Dynamic Spectrum Management scheme (SSDSM). Within the SSDSM framework, cognitive user energy undergoes intelligent sensing, while QoS is governed through dynamic spectrum management. The proposed scheme optimizes service response time by refining fuzzy-based controllers and curtails energy consumption through periodic sensing triggered by predefined rules. Operationalizing within a centralized paradigm, the entire network is overseen by a central controlling node, tasked with formulating an optimal channel list using the SSDSM scheme and allocating it to cognitive users. The efficacy of the proposed scheme is evaluated and validated through rigorous testing using MATLAB. Results reveal tangible enhancements in system efficiency, encompassing maximized throughput, reduced handoff ratio, and minimized service response delay. This research contributes to the ongoing discourse on advancing the performance metrics of cognitive radio networks in the pursuit of reliable and sustainable wireless communication services.

Analyzing device-to-device communication performance with amplify-and-forward relaying amid co-channel interference

<p>Currently, the pressing issue of spectrum limitation, driven by the increasing demand for wireless communication services, has led to the challenge of co-channel interference (CCI) due to the reuse of frequencies in wireless networks. To address this, non-orthogonal multiple access (NOMA) has emerged as a solution. This report conducts a thorough evaluation of NOMA’s system performance over independent and non-identical Rayleigh fading channels in device-to-device (D2D) communications networks, where CCI is significant. The analysis includes examining the probability density function (PDF) and cumulative distribution function (CDF) of the upper SINR threshold. Communication channels are defined as independent and non-identical Rayleigh fading channels, and probability expressions are formulated to assess system failure likelihood for two users. Additionally, Monte-Carlo simulations are conducted to validate the proposed theoretical mathematical expressions.</p>

The Path Towards Virtualized Wireless Communications: A Survey and Research Challenges

To keep up with the increasing number of connected devices in people’s daily lives, it is necessary to develop intelligent mechanisms that perform the entire network management, interconnecting Wi-Fi, and the emerging beyond Fifth-Generation (5G) communications. Hence, it is essential to consider multiple usage scenarios, while managing end devices’ limitations. As a result, developing a system that allows network operators to link Wi-Fi services on their main networks becomes a critical issue. These include a new paradigm that tackles optimal and dynamic resource allocation techniques. Thus, to consider in a combined way, the applications requirements, the resources available, and the different tiers involved, mechanisms such as virtualization and slicing have emerged to handle the heterogeneous context of the next-generation wireless communications. Moreover, the allocation of Radio Access Network (RAN) resources needs to be addressed. For this purpose, Open-RAN has in mind an open environment, which relies on virtualized functions and is mostly vendor agnostic. This technology will enable high data rates while maintaining adequate Quality of Service (QoS) in wireless communications. This paper advances current literature, which mainly discusses these themes individually, by providing a comprehensive survey in Next Generation Wireless Communications, highlighting their integration with beyond 5G Communications. First, we introduce the Wi-Fi evolution and explain the main standards developed over the years. Second, we present the most recent Wi-Fi standards, Wi-Fi 6 and 7, compared with 5G and beyond. Lastly, we explain the concepts related to slicing, virtualization, RAN, Open-RAN and the open research challenges.

For Security and Higher Spectrum Efficiency: A Variable Packing Ratio Transmission System Based on Faster-Than-Nyquist and Deep Learning

With the rapid development of various services in wireless communications, spectrum resource has become increasingly valuable. Faster than Nyquist (FTN) signaling, proposed in the 1970s, is a promising paradigm for improving spectrum utilization. This paper proposes the variable-packing-ratio (VPR)-based transmissions for high spectrum efficiency (SE) and security, respectively. Aided by deep learning (DL)-based estimation, the proposed scheme for high SE can achieve a higher capacity than the conventional Nyquist-criterion transmission with negligible modification to existing communication paradigms (e.g., spectrum allocation or frame structure). More importantly, for VPR-based secure transmission, a dynamic generation scheme is proposed to produce randomly distributed positions to switch the packing ratio, which can effectively avoid detections and attacks. In addition, we propose a simplified DL-based packing ratio estimation for both of these two scenarios so that the receiver can estimate the packing ratio without any in-band or out-band control messages. Simulation results show that the proposed simplified estimation achieves nearly the same accuracy and convergence speed as the original multi-branch fully-connected structure with a complexity reduction of 20 folds. Finally, we derive the closed-form SE of the proposed VPR transmission under different channels. The numerical results validate the correctness of the derivation and demonstrate the SE gains of the VPR scheme beyond conventional Nyquist transmission.

Deployment of Energy-Efficient Aerial Communication Platforms With Low-Complexity Detection

Due to their flexibility, mobility and autonomy, unmanned aerial vehicles (UAVs) are considered as a potential candidate to operate as flying base stations to provide a specific geographical area with air-to-ground wireless communications services. Besides, the limitation of the on-board energy motivates the design of a more energy-efficient way to transmit information. Moreover, the deployment of multiple UAVs can affect the quality of experience (QoE) of users. In this paper, we propose a method that combines the concept of index modulation (IM) with the UAV communications systems, which we refer to as IM-UAV, to attain an improved energy-efficiency (EE). Furthermore, based on the proposed IM-UAV communication system, a gradient descent based UAV deployment scheme is designed to maximize the downlink average rate of the ground users (GUs) in the target area. On the other hand, the maximum likelihood (ML) detection for the IM-UAV requires a high computational complexity for detection at the GUs, while providing the best possible performance. Hence, we propose a low-complexity detection scheme that can separately detect the index symbols and data symbols to reduce the computational complexity at the receiver side. The simulation results demonstrate that the proposed deployment method is capable of attaining the appropriate positions to deploy the UAVs, while the EE is also improved by combining IM with UAV communication system. In addition, the proposed low-complexity detection scheme reduces the computation complexity by slightly sacrificing the bit error rate (BER) performance.

Optimization of UAV 3D trajectory in a post-disaster area using dual energy-aware bandits

In a post-disaster area, Unmanned Aerial Vehicles (UAVs) are considered one of the most effective ways to provide emergency wireless communication services. In this letter, we investigate the UAV-based emergency wireless communication network for a post-disaster area. Our optimization problem aims to optimize the UAV 3D flight trajectory to maximize the number of visited ground users during the flight round. Then, a dual-cost-aware multi-armed bandit algorithm is adopted to tackle this problem under the limited available energy for both the UAV and ground users. Finally, simulation results show that the proposed algorithm could solve the optimization problem and maximize the achievable throughput under these constraints.

Performance analysis of pulse shaping rectangular pulse through frequency selective fading transmission channel in OFDM system

- Long Term Evolution or LTE is a fourth generation (4G) cellular network technology that uses OFDM as its multiplexing technique for fast and effective wireless communication services. OFDM uses the concept of orthogonality for bandwidth efficiency by multiplexing overlapping subcarriers. But in its implementation, this system will have problems in the transmission channel. In addition, OFDM has the major drawback of being susceptible to frequency offset between the transmitter and receiver. This offset frequency will cause the orthogonal character built in the OFDM system to experience a decrease in performance. This decrease in performance is due to the occurrence of ICI. To overcome this, a method is needed to improve system performance. The method used in this research is Rectangular Pulse. Therefore, this research is made to combine the advantages of OFDM and pulse shaping and is expected to produce a superior system and can contribute to the improvement of 4G-LTE implementation. The approach method in this research applies a quantitative descriptive approach to analyze system performance and in this research uses the simulation method as a reference to obtain research data using the Matlab application.

Cooperative hybrid beamforming design in Multi‐UAV MmWave MIMO systems

AbstractDue to the limitation of mobility and cost, it is inappropriate to utilize ground base station (GBS) to provide service in emergency scenarios or harsh environments. Unmanned aerial vehicle (UAV) is considered as a feasible way to solve the problem. Millimetre wave communication and UAV can be used together to offer wireless communications flexibly and rapidly for target area. However, fuselage jittering and energy supply would affect the quality and reliability of UAV communication seriously. To overcome the weakness of UAV, the authors prefer to use multiple UAVs to provide wireless communication service simultaneously. This paper investigates the design of hybrid beamforming in the scenarios including multiple UAVs and one end user. Cooperation strategy and alternating optimization method are applied in this design. The distributed UAV base stations are regarded as an entirety and the reference beamforming scheme obtained. Then, the beamforming problem for each UAV is formulated. Moreover, residual error minimization (REM) algorithm is proposed to find the solution of hybrid beamformers at UAV side. Finally, the beamformer of the receiver is optimized with the assist of effective channel, which includes the gain of both channel and beamformers of the transmitters. Simulation results show that the proposed algorithm can achieve near‐optimal spectral efficiency in different scenarios.

Quad-Band Uniformly Spaced Array Antenna Using Diverse Patch and Fractal Antennas

Multi-band antennas have received significant interest because they can support multiple wireless communication services with a single antenna. However, an array antenna consisting of these element antennas can suffer from non-periodic arrangement due to the irregular sizes of the elements. In this paper, various shapes of patch antennas with fractal antennas are used to ensure the periodic arrangement of the array antenna, and antenna array incorporated with a feed network is proposed. Four different antenna arrays operating at 2.45/3.7/4.3/5.0 GHz are aggregated in an antenna with interleaved disposition of the different element antennas. It is observed that mutual couplings between two elements are sufficiently low, at less than −23 dB. Peak antenna gain ranging from 11.1 dBi to 14.4 dBi at the four different bands is obtained.

Broadband wireless communication with space-time-varying polarization-converting metasurface

Abstract Reconfigurable metasurfaces have emerged as a promising alternative to the conventional transmitter of wireless communication systems, due to their abilities of encoding digital information onto electromagnetic properties without complex radio-frequency chains. However, most of them are still limited to narrow operation bandwidth. Here, we propose a broadband metasurface-based wireless communication system that can actively adapt to multiple users located at versatile directions through joint modulation of digital signals in the time domain and wave scatterings in the space domain. As exemplary demonstrations, highly directive beams are generated to enhance regional signals in real-time customized for users in desired directions and reduce the signal leakage in undesired directions. Experiments are carried out to verify that the system can provide stable wireless communication service in a broad band of 3.7–5.1 GHz, within which the transmitted color picture enabled by the time-varying spatial modulation of metasurface can be successfully recovered at the user terminals. The proposed system may offer untapped potentials for next-generation communications and radar systems where regional signal enhancement, active adaption to users, and large channel capacities are required.

Perancangan Media Pembelajaran Interaktif Konsep Dasar Seluler Menggunakan Aplikasi Unity Berbasis Android

Telecommunication is the most important thing in this era of globalization, there are many ways to transfer information both conventionally and with the help of technology, the use of technology can be online or offline in the current era of digitalization, there have been many developments in telecommunication networks passed, the development of this cellular network has evolved from 1G, 2G, 3G even 4G, the "G" in 1G to 4G now refers to the term "generation". What is meant by generation here is the generation of wireless data and communication service technology, especially for mobile phones, because mobile social media users worldwide have increased rapidly from year to year. Android technology as a tool to use it. Interactive learning media are considered more effective in conveying material to students because students actively use interactive learning media to study the information in it. curriculum and seem too simple so that the educational program is not achieved. Using the Unity application in making Android-based interactive learning media is a form of learning that supports learning in the 21st century, especially the use of software. Of course, we need software to make a game. One of the software that can be used to make games is Unity. Unity is a cross-platform game engine designed to be easy to use. Like making a game that can be run on a computer. The material presented is in the form of general architecture of cellular systems using Unity.