Generation Wireless Communication Research Articles

Introduction of a 5G-Enabled Architecture for the Realization of Industry 4.0 Use Cases

The increasing demand for highly customized products, as well as flexible production lines, can be seen as trigger for the “fourth industrial revolution”, referred to as “Industry 4.0”. Current systems usually rely on wire-line technologies to connect sensors and actuators, but new use cases such as moving robots or drones demand a higher flexibility on communication services. Wireless technologies, especially 5th generation wireless communication systems (5G) are best suited to address these new requirements. Furthermore, this facilitates the renewal of brownfield deployments to enable a smooth migration to Industry 4.0. This paper presents results from the Tactile Internet 4.0 (TACNET 4.0) project and introduces a tailored architecture that is focused on the communication needs given by representative Industry 4.0 use cases while ensuring parallel compliance to latest developments in relevant standardization.

Real Time Arrhythmia Monitoring and Classification Based on Edge Computing and DNN

In this paper, we investigate how to incorporate intelligence into the human‐centric IoT edges to detect arrhythmia, a heart condition often associated with morbidity and even mortality. We propose a classification algorithm based on the intrapatient convolutional neural network model and the interpatient attention residual network model to automatically identify the type of arrhythmia in the edges. As the imbalance categories in the MIT‐BIH arrhythmia database which needs to be used in the algorithm, we slice and overlap the original ECG signal to homogenize the heartbeat sets of different types, and then the preprocessed data was used to train the two proposed network models; the results reached an overall accuracy rate of 99.03% and an F1 value of 0.87, respectively. The proposed algorithm model can be used as a real‐time diagnostic tool for the remote E‐health system in next generation wireless communication networks.

Implications of mmWave Radiation on Human Health: State of the Art Threshold Levels

millimeter (mmWave) frequencies are covering from 30GHz to 300GHz in the electromagnetic spectrum and their uses in various applications like next-generation wireless communication systems (massive 5G telecommunications network), medical devices, airport security and automatic collision avoidance systems are growing vastly in the near future. Therefore, it is important to study the effects of mmWave radiation (non-ionization radiation) on biological systems and biophysical mechanisms. This paper focus on thorough review of nascent literature about current understandings of biological effects and epidemiological studies due to mmWave radiation in human beings. It presents latest guidelines with quantitative electromagnetic field thresholds by considering the realistic exposure scenarios of “general public” and “occupational” who undergo through wireless communication sources in their daily life. It also gives necessary safety measures to be taken while using the emerging mmWave technologies for future generation wireless communication networks.

Possible adoption of various machine learning techniques in cognitive radio - a survey

The concept of cognitive radio (CR) system is the need for next generation wireless communication technology in terms of providing intelligence and superior performance to a wireless device. The CR is mainly an intelligent system which is aware of its environment and is well capable to adapt in accordance with the changing environment and user needs. The concept of adaptation of the communication system can be realised well with machine learning capability inculcated within the system. It is a well-known fact that, the key strengths of any machine learning paradigm is its ability to adapt with respect to the dynamic changing system parameters. In this paper, an attempt has been made to compile various applications of machine learning techniques for different activities of CR cycle. Further, this note reviews the work on development of machine learning techniques for spectrum sensing of CR in order to make the CR system as a whole practically feasible and robust, thus mitigating its existing computational limitations due to the use of conventional techniques.

Pilot Contamination Mitigation in Massive Multi-Input Multi-Output (MIMO) System

Massive MIMO is one of the key components in the technologies of the next generation wireless communication network; the fifth generation (5G). Although massive MIMO is considered a promising technology in 5G, its efficiency is limited by the challenge of the pilot contamination problem. Pilot contamination problem occurs when user terminals in different cells concurrently share the same control signal set (called pilot sets), which results in causing interference in the estimated channel. In this paper, a model to reduce the pilot contamination problem and to increase the system sum-rate is proposed. The proposed model is a combination of three schemes: 1) A time-shifting protocol where the pilots are transmitted by users without overlapping in time; 2) A directional pilot scheme where the users directionally transmit the pilot; 3) A pilot allocation scheme for channel estimation based on the greedy algorithm to optimize the system sum-rate and the signal to interference and noise ratio with low complexity, and to mitigate the pilot contamination. Simulation results show that significant improvements are achieved compared to existing directional, time shifting and pilot allocation schemes.

A Nearly Optimal Method of Polar Code Constructions for the AWGN Channel

Polar code is a kind of capacity-approaching code with explicit structure as part of the next generation wireless communication standard. The performance of the polar code is directly determined by the construction method, in which there are three important parameters: code rate $(R)$ , block-length $(N)$ , and designSNR ( DSNR ). It is very difficult to obtain an optimal construction because all these three parameters should be optimized in a recursive structure model. In this article, an efficient method, which constructs the desired optimal polar code by simultaneously selecting the three parameters in terms of the error probability, is presented. In the proposed construction, a dimensionality reduction search method is used to solve a fore mentioned optimization problem and to find the relation between the performance of polar code and design parameters. At the same time, the optimal parameters $N$ and $R$ can be obtained under any DSNR by taking the average group accuracy rate as the evaluation criterion. Through this method, the appropriate solution of three parameters in the construction of the polar code can be determined according to the required error probability. The proposed construction method is verified by numerical simulation, and the optimal performance to $N$ , $R $ and DSNR is compared and discussed.

Secrecy performance of FSO communication systems with non‐zero boresight pointing errors

Free space optical (FSO) communication is a promising candidate for the next generation (5G and beyond) wireless communication systems, due to its merits (i.e. low latency, high data rate, and license-free band, among others). However, atmospheric turbulence (AT) as well as pointing error (PE) are two of the main challenges with FSO communication that affect its performance. Here, the exact closed-form expression of the average secrecy capacity and secrecy outage probability under the composite effect of AT and non-zero boresight PEs is evaluated. For all the regimes of the AT (weak to strong), a generalised Malaga distribution is used to model the channel fading gain of the FSO link. The expressions are generalised and valid for all turbulence, and are applicable for intensity modulation direct detection as well as heterodyne detection techniques.

Energy detection investigation over composite [formula omitted]/inverse-gamma wireless channel

Proper utilization of the unused spectrum hole facilitates the expanding necessity of the elevated data rate in the upcoming 5th Generation (5G) wireless communication technology. Energy detection is a widely worked technique to fulfill this requirement with minimal time, cost, and efforts. With this motivation, this work develops an analytical framework to analyze the functioning of an energy detector (ED) based cognitive radio (CR) system over a composite fading distribution, characterized by α-μ/Inverse-Gamma (I-Gamma) composite fading channel. To begin with, closed-form expressions for the probability density function (PDF) are developed for single-input single-output (SISO) and single-input multiple-output (SIMO) channels. Exploiting these expressions, analytical results for the average probability of detection (PD) and the average area under the receiver operating characteristic curve (AUC) are obtained. Further, the breakdown is extended in determining average PD under high and very low signal-to-noise ratio (SNR) regime. Finally, the results are utilized as an application in analyzing the cooperative spectrum sensing (CSS) under different shadowing conditions. The optimization of the number of cognitive radios is carried out using the r-out-of-N voting rule. The validation of all the proposed results and their accuracy is determined using the Monte-Carlo simulations.

Feeder Communication for Integrated Networks

The integrated communication system has received increasing attention to establish a fully connected world in the eras of beyond fifth generation wireless communication and sixth generation wireless communication systems, where a wide range of services with distinct requirements needs to be accommodated, covering distinct scenarios such as terrestrial, ocean, outer space, and underwater. In this article, we first propose the idea of feeder communication, which aims to provide truly seamless and ubiquitous on-demand coverage for any human activity. Compared to the traditional integrated networks, feeder communication focuses on reliable data transmission over multiple propagation media such as outer space, stratosphere, troposphere, and underwater. Due to the significant differences of radio propagation characteristics in different media, feeder communication requires a large number of feeder nodes for inter-medium transmissions, a well-designed network structure, and intelligent wireless transmission and control schemes. The basic concepts, features, application scenarios, network architecture, and the corresponding wireless transmission technologies of feeder communication are presented in detail, and challenges and future directions are also pointed out in this article.

(Plenary) The Revival of Compound Semiconductors and How They Will Change the World in a 5G/6G Era

Compound semiconductor devices have always intrigued the semiconductor industry due to their high intrinsic mobilities and the heterostructure engineering enabled by those materials. While CMOS has been the vehicle pushing the industry to ever smaller devices, better performance and of course reduced cost, the unique properties of compound semiconductor devices are finding renewed interest in an era where an increasing amount of data is being sent around, stored and analyzed. While several applications like photonics, high-power electronics and image sensors also benefit from enabling a variety of III-V materials and devices, specifically, in the RF Front-End Modules of 5G radio chips [1], these materials allow to address the challenges related to speed, efficiency and output power needed for this next generation wireless communication standard. And while 5G is in full deployment, with first addressing the sub-6GHz frequency bands and in a later phase the mm-wave frequency bands, first publications are already appearing on 6G, where even higher frequencies (beyond > 100GHz) will be targeted [2].GaN [3] and InP-based devices [4] have a clear performance advantage over Si CMOS and SiGe HBT/BICMOS, but their lower integration potential, still restricted to smaller size substrates and lab-like processing today, is one of the key limitations for adopting those technologies for high-volume 5G and 6G applications. Upscaling those devices to a 200mm/300mm Si platform will be a first step to improve yield and maturity and increase complexity. In a second phase, upscaling and maturing these technologies will allow to co-integrate these devices, usually quite dissimilar to CMOS, with advanced Si technology nodes and provide a fully integrated heterogeneous system.In this talk, we will review the status and progress toward integrating these devices on a CMOS-compatible platform.

Guest Editorial 5G Wireless Communications With High Mobility

The fifth generation (5G) wireless communication networks are expected to support communications with high mobility, e.g., with a speed up to 500 km/h. Hence 5G communications will have numerous applications in high mobility scenarios, such as high speed railways (HSRs), vehicular ad hoc networks, and unmanned aerial vehicles (UAVs) communications [1] – [3] . The 5G systems will provide advanced communication platforms enabling reliable transmission for the Wireless Train Backbone (WLTB) or Wireless Train Control & Management System (WTCMS) [4] , [5] . They will also enable new services or enhancements for vehicular communications in Intelligent Transportation System (ITS) [6] – [9] . The coordination and swarming control for UAVs will also benefit from 5G capabilities, as UAV-based 5G infrastructure modeling and improvement have begun receiving attention [10] . In general, high mobility communication is not only about how large is the maximum speed, it is more about the challenges caused by mobility. In high mobility scenarios, a wireless channel is rapidly time varying, Doppler shifts and spreads can be much larger than those in cellular communications, and if modeled statistically, the channel will be non-wide-sense stationary (non-WSS) over a short time period. In addition, network topology can change quickly, and switching among base stations (BSs) and/or peer nodes can be more frequent, not forgetting 5G challenges in cross-border mobility [11] .

5G-Compliant Authentication Protocol for RFID

The term “Internet of Things” was originally coined when radio frequency identification (RFID) technology was being developed to refer to applications where RFID tagged objects and sensors enabled computers to achieve effective situational awareness without human intervention. Currently, this term encompasses a myriad of medium/small devices connected to the Internet. On the other hand, 5G is a key enabling technology that will support next generation wireless communications. Moreover, 5G aims to realize the “Internet of Everything”. Surprisingly, despite the expected relationship between these two technologies, RFID tags have not been properly integrated into 4G and it is not clear if this will change in 5G. RFID is considered as a parallel technology where, at best, it has connection to the core network using back-end servers as gateways between the two technologies. With the aim of overcoming this problem, this paper proposes a 5G compliant RFID protocol that allows RFID tags to act as fully fledged 5G subscribers while taking into account the main characteristics of RFID systems. This proposal leverages the separation between USIM and mobile equipment within the user equipment to implement a 5G compliant protocol where tags accomplish the authentication part, as 5G subscribers, while readers assume the mobile equipment role, carrying out the 5G communication and most of the resource consuming tasks.

On the Uplink Transmission of Extra-Large Scale Massive MIMO Systems

With the inherent benefits, such as, better cell coverage and higher area throughput, extra-large scale massive multiple-input multiple-output (MIMO) has great potential to be one of the key technologies for the next generation wireless communication systems. However, in practice, when the antenna dimensions grow large, spatial non-stationarities occur and users will only see a portion of the base station antenna array, which we call visibility region (VR). To assess the impact of spatial non-stationarities, in this paper, we investigate the uplink transmission of extra-large scale massive MIMO systems by considering VRs. In particular, we first propose a subarray-based system architecture for extra-large scale massive MIMO systems. Then, tight closed-form uplink spectral efficiency (SE) approximations with linear receivers are derived. With the objective of maximizing the achievable SE, we also propose schemes for the subarray phase coefficient design. In addition, based on the obtained ergodic achievable SE approximations, two statistical channel state information (CSI)-based greedy user scheduling algorithms are developed. Our results indicate that the statistical CSI-based greedy joint user and subarray scheduling algorithm collaborating with the on-off switch-based subarray architecture is a promising practical solution for extra-large scale massive MIMO systems.

Design of Helical Antenna for Next Generation Wireless Communication

This study proposes a novel helical antenna design for next generation applications. The strip helical antenna is prescribed for next generation wireless communication and wideband applications that offer circular polarization and a wide bandwidth. In fact, the proposed helical antenna suits 5.8 GHz frequency by using Teflon material. The newly-designed strip was printed on a substrate and rolled into a helix shape to achieve circular polarization without impedance matching. This antenna is meant for wideband wireless communication applications. A wide bandwidth of 2.7 GHz with 5.8 GHz resonant frequency was attained through the use of helical antenna on Teflon substrate. The proposed antenna on Teflon substrate recorded a gain of 8.97 dB and 92 efficiency. The antenna design parameters and the simulated results were retrieved using Computer Simulation Technology software (CST). The measurement result of return loss displayed mismatch at 5.22 GHz due to manual fabrication. This developed antenna may be applied for a number of wireless applications, including Wideband, Ultra-wideband, and 5G. © 2020 Wydawnictwo SIGMA-NOT. All rights reserved.

Channel Measurements and Modeling for 400–600-MHz Bands in Urban and Suburban Scenarios

Sub-1 GHz bands have been used for many years and now some of them will be reallocated for new applications, including the fifth generation (5G) wireless communication systems and beyond, Internet of Things (IoT), smart grid, etc. As the well-known path-loss (PL) models are mainly applicable in 2-6-GHz frequency range, a new channel measurement campaign is needed to study the propagation characteristics at sub-1 GHz bands. In this article, we conduct fixed-to-mobile wideband channel measurements at 400-600-MHz bands in urban and suburban scenarios using the time domain channel sounder. As the interference and noise signals are severe, the transmitted waveform is carefully designed to enlarge the system dynamic range. Meanwhile, ray tracing simulation is applied to construct the measurement environments and do the mutual verification with measurement results. The two-slope PL model and lognormal shadowing fading model are proposed for large-scale fading channel modeling. The root mean square (RMS) delay spread (DS), number of paths, and diffraction characteristics are also analyzed. The results will have great importance for the coming new applications at sub-1 GHz bands.

Mobility-Aware Subband and Beam Resource Allocation Schemes for Millimeter Wave Wireless Networks

Millimeter wave (mmWave) has been widely considered as a promising technology in the next generation wireless communication systems. Various beam-based directional transmission techniques have been proposed to compensate high pathloss caused by mmWave properties. However, mobility effect of users potentially causes severe inter-beam interferences, which has not been fully-investigated in existing studies. In this paper, we have analyzed different types of mobility-aware beam interference models. Additionally, the theoretical SINR is derived based on channel statistics and the trajectories of users. We propose a mobility-aware subband and beam resource allocation (MSBA) scheme for the mmWave subband-beam massive multi-input multi-output (SB-MMIMO) systems. The proposed MSBA benefits from reduced computation complexity for maximizing system throughput constrained by quality-of-service (QoS) demands of users. The first phase of MSBA scheme is responsible for resource block assignment; while the second phase allocates beamwidth and beam directions according to the analytical derivations. Numerical results show that the proposed MSBA scheme can effectively achieve the highest system throughput and the lowest complexity compared to existing schemes in open literatures.

Millimeter‐wave propagation modeling and characterization at 32 GHz in indoor office for 5G networks

Since it has a great bandwidth that supports gigabit communication, it is considered to use the millimeter-wave (mmWave) band in the fifth generation (5G) wireless communication. Therefore, an efficient, reliable, and accurate channel model is of vital importance in mmWave bands for indoor environments, especially in the 31.8 to 33.4 GHz band allocated by ITU for 5G communications. In this article, we performed modeling and characterization campaign at the 32 GHz in a typical indoor office environment on fourth floor of the Engineering Faculty in University of Karabuk, Turkey. The obtained results provide large-scale fadings such as path loss, shadowing, root mean square (RMS) delay spread, RMS angular spread, power angular spectrum, number of clusters, and Ricean K-factor in an open-plan indoor environment. Power angular spectrum is used to comprehend the propagation structure. We propose that the results obtained in this study will play a key role in simulating and planning systems at 32 GHz for 5G wireless communication.

Sum Secret Key Rate Maximization for TDD Multi-User Massive MIMO Wireless Networks

Physical-layer key generation (PKG) based on channel reciprocity has recently emerged as a new technique to establish secret keys between devices. Most works focus on pairwise communication scenarios with single or small-scale antennas. However, the fifth generation (5G) wireless communications employ massive multiple-input multiple-output (MIMO) to support multiple users simultaneously, bringing serious overhead of reciprocal channel acquisition. This paper presents a multi-user secret key generation in massive MIMO wireless networks. We provide a beam domain channel model, in which different elements represent the channel gains from different transmit directions to different receive directions. Based on this channel model, we analyze the secret key rate and derive a closed-form expression under independent channel conditions. To maximize the sum secret key rate, we provide the optimal conditions for the Kronecker product of the precoding and receiving matrices and propose an algorithm to generate these matrices with pilot reuse. The proposed optimization design can significantly reduce the pilot overhead of the reciprocal channel state information acquisition. Furthermore, we analyze the security under the channel correlation between user terminals (UTs), and propose a low overhead multi-user secret key generation with non-overlapping beams between UTs. Simulation results demonstrate the near-optimal performance of the proposed precoding and receiving matrices design and the advantages of the non-overlapping beam allocation.

Intelligent Time-Varying Metasurface Transceiver for Index Modulation in 6G Wireless Networks

Index modulation (IM) is one of the candidate technologies for the upcoming sixth generation (6G) wireless communications networks. In this paper, we propose a space-time-modulated reconfigurable intelligent metasurface (RI-MTS) that is configured to implement various frequency-domain IM techniques in a multiple-input multiple-output (MIMO) array configuration. Unlike prior works which mostly analyze signal theory of general RI-MTS IM, we present novel electromagnetics-compliant designs of specific IMs such as sub-carrier index modulation (SIM) and MIMO orthogonal frequency-domain modulation IM (MIMO-OFDM-IM). Our full-wave electromagnetic simulations and analytical computations establish the programmable ability of these transceivers to vary the reflection phase and generate frequency harmonics for IM. Our experiments for bit error rate show that RI-MTS-based SIM and MIMO-OFDM-IM are lower than conventional MIMO-OFDM.

Design, Simulation and Analysis of a High Gain Small Size Array Antenna for 5G Wireless Communication

Microstrip antennas have become a part and parcel of today’s wireless communication world because of their low profile, low cost and ease of fabrication in the circuit boards. But poor performances like narrow bandwidth, low power handling capability, low gain etc. confine their application in some cases. 5th generation (5G) wireless communication will suffer from path loss severely, as high frequency bands will be used. To manage this problem, high gain antenna is required. So, this research is mainly devoted to design a high gain 2 × 2 microstrip patch array antenna. The structure of the antenna is designed and simulated using CST Microwave Studio and operates at 28 GHz 5G band. Rogers RT-Duroid 5880LZ is used as the substrate which has a relative permittivity of 1.96. The return loss, gain, bandwidth, VSWR and efficiency of the designed 2 × 2 array antenna is 87 dB, 14 dBi, 1.14 GHz, 1 and almost 93% respectively.