Generation Wireless Communication Systems Research Articles

Internet of Things and Next Generation Wireless Communication Systems

Next generation wireless communication systems will connect billions of Internet of Thing (IoT) devices and user elements along with billions of people, enable machine-to-ma-chine communications across heterogeneous and dynamic environment, and provide low-latency computing and storage resources on demand at the deep edge as well as in the cloud. Tremendous research and development efforts have already been emphasized on the enabling technologies toward next generation wireless systems to support a variety of critical and personalized services in multiple application domains, including industry use cases, environment, transportation, education, public health and safety, and defense. Wireless communication networks have been greatly advanced by exploiting technologies such as millimeter wave, dynamic spectrum sharing, massive MIMO, beam forming, network slicing and virtualization, and artificial intelligence and machine learning. These technology breakthroughs can empower wireless networks to support extreme high capacity, massive connectivity, and ultra-low latency communications for new use cases identified for next generation wireless systems. In order to design and deploy wireless communication systems with IoT devices across heterogeneous and dynamic environments to provide next generation wireless services, however, there are many critical technical challenges yet to be addressed. In this issue of IEEE Wireless Communications, we are pleased to present two feature topics to bring together researchers, industry practitioners, and individuals working on the related areas to address some of these technical challenges for IoT and next generation wireless systems. One feature topic on “Massive Machine-Type Communications for IoT” includes four articles, and was organized by guest editors W. Ji, T. Ebrahimi, Z. Li, J. Yuan, D. O. Wu, and Y. Xin; the other feature topic on “Emerging Visual IoT Technologies for Future Communications and Networks” includes six articles, and was organized by guest editors L. Liu, E. G. Larsson, P. Popovski, G. Caire, X. Chen, and S. R. Khosravirad. Thanks to the two guest editor teams who did an excellent job in editing these two feature topics for our readers. Please stay tuned for new developments in the research area of IoT and next generation wireless communications and read the editorials and the papers in the feature topics.

Accelerating Simulations of Large Scale Phased-Array Systems

Next generation wireless communications systems operating at millimeter-wave frequencies are utilizing phased arrays of increasing electrical size to overcome path loss. The size of these arrays can make simulations become infeasible due to the amount of computation and memory required. Here we discuss parallelization and hardware acceleration methods to overcome these obstacles for large scale phased array systems. The acceleration of these methods was quantified using an orthogonal frequency division multiplexing frequency-domain simulator.

Efficient and Robust Image Communication Techniques for 5G Applications in Smart Cities

A wide range of multimedia applications must be supported by the modern fifth generation (5G) wireless communication systems for realizing the diverse applications in smart cities. The diverse applications such as real-time monitoring of roads, smart homes, smart industries, etc., for a sustainable smart city emphasizes a robust and efficient image transmission. In this paper, the influence of maximal ratio combining (MRC) on the reception of images with different orthogonal frequency division multiplexing (OFDM) versions is studied. The different OFDM versions considered here are the fast Fourier transform (FFT) based OFDM and discrete cosine transform (DCT) based OFDM. A comparison between diverse modulation levels for the images transmitted through different OFDM methodologies, along with variation in a number of receiving antennas for MRC, is proposed for additive white gaussian noise (AWGN) and Rayleigh fading channels. The diverse modulation levels used are binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), 8-PSK, and 16-PSK. The parameters that are used to compare different versions of OFDM for MRC antenna configurations are signal-to-noise ratio (SNR) vs. bit error rate (BER) and peak signal-to-noise ratio (PSNR) at the receiver as an estimation parameter for the received image quality.

Channel aware receiver for next generation wireless communication system

Channel aware receiver for next generation wireless communication system

Multi-Hop RIS-Empowered Terahertz Communications: A DRL-Based Hybrid Beamforming Design

Wireless communication in the TeraHertz band (0.1-10 THz) is envisioned as one of the key enabling technologies for the future sixth generation (6G) wireless communication systems scaled up beyond massive multiple input multiple output (Massive-MIMO) technology. However, very high propagation attenuations and molecular absorptions of THz frequencies often limit the signal transmission distance and coverage range. Benefited from the recent breakthrough on the reconfigurable intelligent surfaces (RIS) for realizing smart radio propagation environment, we propose a novel hybrid beamforming scheme for the multi-hop RIS-assisted communication networks to improve the coverage range at THz-band frequencies. Particularly, multiple passive and controllable RISs are deployed to assist the transmissions between the base station (BS) and multiple single-antenna users. We investigate the joint design of digital beamforming matrix at the BS and analog beamforming matrices at the RISs, by leveraging the recent advances in deep reinforcement learning (DRL) to combat the propagation loss. To improve the convergence of the proposed DRL-based algorithm, two algorithms are then designed to initialize the digital beamforming and the analog beamforming matrices utilizing the alternating optimization technique. Simulation results show that our proposed scheme is able to improve 50% more coverage range of THz communications compared with the benchmarks. Furthermore, it is also shown that our proposed DRL-based method is a state-of-the-art method to solve the NP-hard beamforming problem, especially when the signals at RIS-assisted THz communication networks experience multiple hops.

THz channel modeling: Consolidating the road to THz communications

For the sake of meeting the demand of data rates at terabit (Tbit) per second scale in future networks, the terahertz (THz) band is widely accepted as one of the potential key enabling technologies for next generation wireless communication systems. With the progressive development of THz devices, regrading THz communications at system level is increasing crucial and captured the interest of plenty of researchers. Within this scope, THz channel modeling serves as an indispensable and fundamental element. By surveying the latest literature findings, this paper reviews the problem of channel modeling in the THz band, with an emphasis on molecular absorption loss, misalignment fading and multipath fading, which are major influence factors in the THz channel modeling. Then, we focus on simulators and experiments in the THz band, after which we give a brief introduction on applications of THz channel models with respects to capacity, security, and sensing as examples. Finally, we discuss some key issues in the future THz channel modeling.

Interference Mitigation in the Wireless Communication Systems Using Adaptive Filters

In the current fifth generation (5G) wireless communication systems, the interference mitigation issue becomes a major and most important task for improving the performance of such systems due to corded spectrum and increased demands for new applications. Antenna arrays controlled by adaptive algorithms are proved to be a good solution for such problem. However, there are still some practical limitations in implementing such fully adaptive arrays especially when consisting a large number of the controllable elements. Other disadvantages of such arrays include long convergence time of the algorithm and the complexity of the beamforming network. In this paper, an adaptive algorithm is connected to only limited number of the array elements instead of all elements. We found that the elements that located on the center of the array could be chosen as adaptive, while the other elements which have less effect on the array pattern are left without adaptation process. Thus, the proposed array has many advantages with compared to those of the fully adaptive arrays while maintaining the same performance in suppressing the interference signals through null steering. Simulation results show that the effectiveness of the proposed array in generating deep nulls with very short convergence time.

A Partial CSI Estimation Approach for Downlink FDD massive-MIMO System with Different Base Transceiver Station Topologies

Massive multiple-input multiple-output (massive-MIMO) is a promising technology for next generation wireless communications systems due to its capability to increase the data rate and meet the enormous ongoing data traffic explosion. However, in non-reciprocal channels, such as those encountered in frequency division duplex (FDD) systems, channel state information (CSI) estimation using downlink (DL) training sequence is to date very challenging issue, especially when the channel exhibits a shorter coherence time. In particular, the availability of sufficiently accurate CSI at the base transceiver station (BTS) allows an efficient precoding design in the DL transmission to be achieved, and thus, reliable communication systems can be obtained. In order to achieve the aforementioned objectives, this paper presents a feasible DL training sequence design based on a partial CSI estimation approach for an FDD massive-MIMO system with a shorter coherence time. To this end, a threshold-based approach is proposed for a suitable DL pilot selection by exploring the statistical information of the channel covariance matrix. The mean square error of the proposed design is derived, and the achievable sum rate and bit-error-rate for maximum ratio transmitter and regularized zero forcing precoding is investigated over different BTS topologies with uniform linear array and uniform rectangular array. The results show that a feasible performance in the DL FDD massive-MIMO systems can be achieved even when a large number of antenna elements are deployed by the BTS and a shorter coherence time is considered.

A Novel Concatenated LWT and WHT Based UFMC Waveform Design for the Next Generation Wireless Communication Systems

A novel concatenated Lifting Wavelet Transform (LWT) and Walsh Hadamard Transform (WHT) with Universal Filtered Multi Carrier (UFMC) waveform is suggested as an alternative to Orthogonal Frequency Division Multiplexing (OFDM) waveform for the next generation wireless telecommunication systems in this paper. The suggested waveform is composed of LWT and WHT with UFMC waveform. Both the elimination the disadvantages of OFDM and the improvement the achievement of UFMC waveform, from the fifth generation waveform candidates, has been aimed with the suggested waveform. In order to verify the performance of the suggested waveform and compare with the traditional OFDM, UFMC, and LWT‐UFMC waveform computer simulation studies are performed in additive white Gaussian noise and flat Rayleigh fading channel environments. The acquired computer simulation results exhibit that the achievement of the suggested waveform has better than the achievement of the traditional OFDM, UFMC, and LWT‐UFMC waveform. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Performance enhancement of relays used for next generation wireless communication networks

<p>Relaying is one of the latest communication technologies developed for wireless networks like WiMAX, LTE Advanced and 5G Ultra Reliable Low Latency Communication (URLLC) networks to provide coverage extension as well as higher bitrates for cell edge users. Thus they are included in the design of next generation wireless communication systems to provide performance improvement in terms of coverage and capacity over their predecessors. Other promising features of this technology include easy to implement and reduction in deployment cost. The objective of this paper is to analyze both cooperative and non-cooperative relaying techniques in the Infinite Block length regime and findout the benefits of Relay implementation. A single Amplify and Forward (A&F) Relay is used for this purpose. Reduction in power requirement for Simple Relay is shown in comparison to the direct transmission, using experimental analysis with Matlab simulation. SER (Symbol error rate) is calculated at the receiver for no relay, simple Relay and Cooperative Relaying scenario to show the improvements of cooperative Relaying implementation.The performance enhancement of the Relay is then carried out using Particle Swam Optimization (PSO) optimization technique where allocation of power between Base station and Relay Node is effectively distributed for optimum performance.</p>

Alternating Beamforming With Intelligent Reflecting Surface Element Allocation

Intelligent reflecting surface (IRS) has become a promising technology to aid next generation wireless communication systems. In this paper, we develop an alternating beamforming technique with a novel concept of IRS element allocation for multiple-input multiple-output systems when a base station supports multiple single antenna users aided with a single IRS. Specifically, we allocate each IRS element separately to each user, thus, in the beamforming stage allowing the IRS element only consider a single user at a time. In result to this separation, the complexity is vastly decreased. The proposed beamforming technique tries to maximize the minimum rate of all users with minimal complexity. In the numerical results, we show that the proposed technique is comparable to the convex optimization-based benchmark with sufficiently less complexity.

Investigation of Ideal Number User Terminals with Spectrum Efficiency in Next Generation Wireless Communication Systems

Suppose that a multi-user multiple-input multiple-output (MIMO) system is developed from scratch to equally envelop a defined region with optimal spectrum efficiency (SE) in next generation wireless communication systems such as sixth-generation (6G) and beyond networks. What are the ideal number of user terminals U, number of base stations antennas, and used pilot reuse factor? The purpose of this paper is to address this specific issue. Three interference levels are specified for this. Based on these interference levels, signal-to-interference-and-noise ratios (SINRs) are extracted. Closed-form spectrum efficiency equations are thus obtained. As a function of the base station (BS) antenna number, simulations are carried out considering multiple pilot reuse factors and diverse processing schemes such as Maximum Ratio Combining (MRC) and Zero-Forcing (ZF). From the results, it is understood that U varies according to the processing schemes. Therefore, evaluating the results considering the fixed number of users K will not give an accurate result in determining the design parameters for the next generation communication systems. In general, these results are useful statements that spectrum efficiency is maximized when the ideal number of users U is used in multi-cell systems.

Energy-Efficient Resources Allocation With Millimeter-Wave Massive MIMO in Ultra Dense HetNets by SWIPT and CoMP

Ultra-dense HetNets (UDN)-based Millimeter-Wave (mmWave) massive MIMO is considered a promising technology for 5th generation (5G) wireless communications systems since it can offer massively available bandwidth and improve energy efficiency (EE) substantially. However, in UDN, the power consumption of the system increases sharply with the increase of network density. In this paper, we investigate the optimization of the EE in the mmWave massive MIMO systems with UDN. To develop the functions of massive MIMO, we first propose a system model where the massive MIMO harvests electromagnetic energy from the environment employing simultaneous wireless information and power transfer (SWIPT) technology, implemented at the base station (BS). Then, the EE optimization problem is formulated for 5G mmWave massive MIMO systems within the UDN. Considering the nonconcave feature of the objective function, an iterative EE algorithm is developed, based on Dinkelbach method. To utilize the role of coordinated multi-point transmission and reception (CoMP) for improving the EE, a coordinated user(UE)-BS association algorithm-based CoMP with maximum energy efficiency (MaxEE) is proposed. The simulation results demonstrate that the proposed algorithm has a substantially faster convergence rate and is very effective, compared with existing methods.

A Low Complexity Detector for Massive MIMO Uplink Systems

Fifth generation wireless communication system is implemented by several mobile companies where important technologies are employed such as the massive multiple-input multiple-output (MIMO). Although it improves the spectrum and energy efficiencies, it is not a trivial to propose an efficient detector for massive MIMO systems because a large number of antennas increases the computational complexity. In this paper, approximate message passing (AMP) is exploited in the massive MIMO uplink (UL) data detection. Although the AMP method is suffering from a considerable performance in special cases, an efficient selection of the initial solution affects greatly the convergence rate, the bit-error-rate performance, and the computational complexity. In this paper, three efficient initialization methods of the AMP-based massive MIMO UL detector are proposed based on iterative methods, namely, the successive overrelaxation, the Gauss–Seidel, and the Jacobi. In addition, a stair matrix is exploited to achieve high convergence rate. Numerical results show that the proposed detector achieved a considerable performance improvement and complexity reduction in comparison with the traditional AMP-based detector.

Federated Learning and Control at the Wireless Network Edge

We are at the cusp of two transformational technologies, namely the fifth generation of wireless communication systems, known as 5G, and machine learning (ML). On the one hand, while the evolutionary part of 5G, enhanced mobile broadband (eMBB), focusing mainly on millimeter-wave transmissions has made significant progress, fundamentals of ultra-reliable and low-latency communication (URLLC), one of the major tenets of the 5G revolution, are yet to be fully understood. In essence, URLLC warrants a departure from average-based system design toward a clean slate design centered on tail, risk, and scale [1]. While risk is encountered when dealing with decision making under uncertainty, scale is driven by the sheer amount of devices, antennas, sensors, and actuators, all of which pose unprecedented challenges in network design, optimization, and scalability.

Lightweight porous silica foams with extreme-low dielectric permittivity and loss for future 6G wireless communication technologies

In the next generation wireless communication systems operating at near terahertz frequencies, dielectric substrates with the lowest possible permittivity and loss factor are becoming essential. In this work, highly porous (98.9% ± 0.1%) and lightweight silica foams (0.025 ± 0.005 g/cm3), that have extremely low relative permittivity (εr = 1.018 ± 0.003 at 300 GHz) and corresponding loss factor (tan δ< 3 × 10−4 at 300 GHz) are synthetized by a template-assisted sol-gel method. After dip-coating the slabs of foams with a thin film of cellulose nanofibers, sufficiently smooth surfaces are obtained, on which it is convenient to deposit electrically conductive planar thin films of metals important for applications in electronics and telecommunication devices. Here, micropatterns of Ag thin films are sputtered on the substrates through a shadow mask to demonstrate double split-ring resonator metamaterial structures as radio frequency filters operating in the sub-THz band.

Dual-Determination of Modulation Types and Signal-to-Noise Ratios Using 2D-ASIQH Features for Next Generation of Wireless Communication Systems

In order to pursue rapid development of the new generation of wireless communication systems and elevate their security and efficiency, this paper proposes a novel scheme for automatic dual determination of modulation types and signal to noise ratios (SNR) for next generations of wireless communication systems, fifth-generation (5G) and beyond. The proposed scheme adopts unique signatures depicted in two-dimensional asynchronously sampled in-phase-quadrature amplitudes' histograms (2D-ASIQHs)-based images and applies the support vector machines (SVMs) tool. Along with the estimation of the instantaneous SNR values over 0-35 dB range, the determination of nine modulation types that belong to different modulation categories i.e., phase-shift keying (Binary-PSK, Quadrature-PSK, and 8-PSK), amplitude-shift keying (2-ASK and 4-ASK) and quadrature-amplitude modulation (4-QAM, 16-QAM, 32-QAM, and 64-QAM) could be achieved by this scheme. The application of this scheme has been simulated using a channel model that is impaired by additive white Gaussian noise (AWGN) and Rayleigh fading, covering a broad range of SNRs of 0-35 dB. The performance of this dual-determination scheme shows high modulation recognition accuracy and low mean SNR estimation error. Therefore, it can be a better alternative for designers of next generation wireless communication systems.

Information Security Mechanisms and ICT Policy in Practice: A Case of the University of Namibia

As new technologies emerge in the next generation of wireless communication systems so the continued rise of cyber threats and attacks in higher education institutions. In the wake of COVID-19, however, institutions of higher learning increasingly searched for alternative ways to deliver remote education. Hence, planning for cyber security became a priority and not an option due to the new level of vulnerability posed by human factors as they utilize both licensed and open-source software and wireless devices. Based on this ground, this paper discussed pertinent points on the examined ICT policy and security mechanisms as security practices and strategies implemented by the University of Namibia’s Directorate of Information & Communication Technology Services before and post the sudden shift to remote learning. It further proposed alternative strategies to curb vulnerabilities as an element of human action. Key findings show that security breaches do happen mostly due to end-user errors and not always technical issues. A qualitative research method with a random sampling technique guided the study. Virtual interviews and a survey have been used to gather data from security specialists, academics, and administrative staff. Data got analyzed in themes. It has been concluded that both people and technology are essential in information security structure. Increased awareness, training, and improved security practices are the key solutions.

Analysis of the gsm communication channel in security systems

The article outlines the basic principles initially; wireless systems were not widely used due to low reliability. But now there is a wide range of various additional devices, and new generations of wireless communication systems are actively used. The capabilities provided by mobile operators are increasingly used in security systems. The capabilities provided by mobile operators are increasingly used in security systems. To date, wireless security systems based on the base have become widespread due to their relatively low cost and ease of installation and operation. The GSM-900/1800 cellular network provides good communication quality and is already deployed in most cities.

Mitigation of Imperfect Successive Interference Cancellation and Wavelet‐Based Nonorthogonal Multiple Access in the 5G Multiuser Downlink Network

The fourth Industrial Revolution is expected to lead to an era of technological innovation and digitization that would require connectivity by the users, anywhere and anytime. The fifth generation of wireless communication systems and the technologies therein are being explored to cater to high connectivity needs that encompass high data rates, very low latencies, energy‐efficient systems, etc. A multiuser environment is anticipated that would require multiple access techniques, such as Nonorthogonal Multiple Access (NOMA). The user data in the power domain NOMA is superimposed, at the transmitter base station, which is in turn subjected to Successive Interference Cancellation at the user end. In the multiuser downlink, the desired user’s signal is subjected to imperfect SIC due to incomplete cancellation of the undesired user’s signal. Pulse‐shaping of NOMA symbols using wavelet transform is proposed to mitigate the multiuser interference due to imperfect SIC. Closed‐form symbol error rate (SER) expression is derived for the wavelet NOMA system for a three‐user scenario. Analytical results show that wavelet transform pulse‐shaped NOMA performs better compared to Fourier transform pulse‐shaped NOMA symbols in mitigating SIC and thereby minimize the residual error due to imperfect SIC.