5G Wireless Communication Research Articles

Comparison of copper and graphene-assembled films in 5G wireless communication and THz electromagnetic-interference shielding

Since first developed, the conducting materials in wireless communication and electromagnetic interference (EMI) shielding devices have been primarily made of metal-based structures. Here, we present a graphene-assembled film (GAF) that can be used to replace copper in such practical electronics. The GAF-based antennas present strong anticorrosive behavior. The GAF ultra-wideband antenna covers the frequency range of 3.7 GHz to 67 GHz with the bandwidth (BW) of 63.3 GHz, which exceed ~110% than the copper foil-based antenna. The GAF Fifth Generation (5G) antenna array features a wider BW and lower sidelobe level compared with that of copper antennas. EMI shielding effectiveness (SE) of GAF also outperforms copper, reaching up to 127 dB in the frequency range of 2.6GHz to 0.32 THz, with a SE per unit thickness of 6,966 dB/mm. We also confirm that GAF metamaterials exhibit promising frequency selection characteristics and angular stability as flexible frequency selective surfaces.

Intelligent metasurface system for automatic tracking of moving targets and wireless communications based on computer vision

The fifth-generation (5G) wireless communication has an urgent need for target tracking. Digital programmable metasurface (DPM) may offer an intelligent and efficient solution owing to its powerful and flexible controls of electromagnetic waves and advantages of lower cost, less complexity and smaller size than the traditional antenna array. Here, we report an intelligent metasurface system to perform target tracking and wireless communications, in which computer vision integrated with a convolutional neural network (CNN) is used to automatically detect the locations of moving targets, and the dual-polarized DPM integrated with a pre-trained artificial neural network (ANN) serves to realize the smart beam tracking and wireless communications. Three groups of experiments are conducted for demonstrating the intelligent system: detection and identification of moving targets, detection of radio-frequency signals, and real-time wireless communications. The proposed method sets the stage for an integrated implementation of target identification, radio environment tracking, and wireless communications. This strategy opens up an avenue for intelligent wireless networks and self-adaptive systems.

Oblique nanomachining of gallium arsenide explained using AFM experiments and MD simulations

Gallium Arsenide (GaAs) continues to remain a material of significant importance due to being a preferred semiconductor substrate for the growth of quantum dots (QDs) and GaAs-based quantum devices used widely in fifth-generation (5G) wireless communication networks. In this paper, we explored aspects of oblique nanomachining to investigate the improvement in the machining quality as well as to understand plasticity and transport phenomena in GaAs using atomic scale machining experiments and simulations. We studied the influence of the direction vector of the cutting tip (e.g. tip alignment) during the surface generation process in GaAs. We noticed a novel observation that when the AFM tip's cutting edge presented two acute angles (i.e., 30° angles each) between the cutting face and the cutting direction (which can be regarded as an oblique cutting condition), the cutting configuration involved early avalanche of dislocations compared to other tip configurations (e.g., orthogonal cutting). Orthogonal cutting involved the least coefficient of friction but the highest specific cutting energy compared to oblique cutting. High-resolution transmission electron microscopy (HRTEM) examination revealed that the shuffle-set slip on the {1 1 1} slip system due to the 〈1 1 0〉 type dislocation paves the way for plasticity during nanometric cutting of GaAs. Overall, a particular condition of oblique cutting was inferred to be the best for nanofabrication of high-quality wafers using an AFM.

A Noval High Gain Compact Antenna for 5G Wireless Communication

A Noval High Gain Compact Antenna for 5G Wireless Communication

Cloud‐assisted authentication scheme supporting dynamic pseudo‐identity for autonomous vehicles

SummaryWithout the involvements of human beings, cyber physical systems (CPSs) run based on many devices distributed everywhere around the smart city. Autonomous vehicles (AVs) occupy a critical part in modern transportation systems under the condition of 5G wireless communication. To help people make decisions, AVs collect and produce instant information on the roads. When messages are trasferred from AVs, real‐time and dependable authentications are required. Recently, a host of signature or key agreement authentication schemes have been proposed by researchers. However, weaknesses appear, such as instant data sent from autonomous vehicles are in plaintext, and attackers can track the identity of the autonomous vehicle even if pseudo‐identity mechanism is employed. In this paper, we introduce a new authentication scheme for AVs in transportation systems. Formal proof with random oracles demonstrates that it is difficult for the adversary to forge the four messages in the public communication environment. Moreover, security properties including vehicle anonymity, traceability and mutual authentication meet the requirements in our discussion. At last, the performation test with miracl library and simulation with NS3 show that the proposed scheme is practical due to completeness of more security targets than others.

Machine Learning in 6G Wireless Communications

Mobile communication systems are not only the core of the Information and Communication Technology (ICT) infrastructure but also that of our social infrastructure. The 5th generation mobile communication system (5G) has already started and is in use. 5G is expected for various use cases in industry and society. Thus, many companies and research institutes are now trying to improve the performance of 5G, that is, 5G Enhancement and the next generation of mobile communication systems (Beyond 5G (6G)). 6G is expected to meet various highly demanding requirements even compared with 5G, such as extremely high data rate, extremely large coverage, extremely low latency, extremely low energy, extremely high reliability, extreme massive connectivity, and so on. Artificial intelligence (AI) and machine learning (ML), AI/ML, will have more important roles than ever in 6G wireless communications with the above extreme high requirements for a diversity of applications, including new combinations of the requirements for new use cases. We can say that AI/ML will be essential for 6G wireless communications. This paper introduces some ML techniques and applications in 6G wireless communications, mainly focusing on the physical layer.

Antenna Array on Glass Interposer for 6G Wireless Communications

This paper demonstrates integrated packaging solutions for antenna components in D-band by using glass-based package. We design sub-terahertz patch antennas at 140 GHz frequency band using HFSS simulation, and form arrays of patch antennas for 6G (sub-THz) wireless communication applications. The patch antennas and feeding networks are implemented using microstrip structures on the top of the interposer, with ground planes beneath. Build-up layers of polymer dry films are laminated on a glass core for multi-layer copper metallization, and copper structures are patterned on the polymer layers. For precise fabrication of the antenna and feeding structures in package, we implement the semi-additive patterning process to deposit the copper structures. Adequate measurement methods are applied to address difficulties in D-band antenna measurements. By forming patch antenna arrays, we obtain 10 dBi gain using a 4-element linear array and 14 dBi gain using a 4-by-4 2-D array. The bandwidths achieved for these arrays are 7% (10 GHz) and 5% (7 GHz), respectively, based on return loss measurements. Overall, the measurement results present good match to simulation. Antenna structures on glass substrates demonstrated in this paper represent the basic building block for heterogeneous integration of D-band front-end module in glass-based packages.

Perspectives on 6G wireless communications

Since its first commercialization in early 2019, 5G has been making progress around the world and penetrating daily lives. Now, research interest in wireless communication is quickly shifting to the next generation mobile system, 6G. This paper envisions the 6G as a union of physical space, cyberspace, and connectivity with intelligence. Also, interactivity is a critical component to provide users with a truly immersive experience. In this paper, 6G usage scenarios and use cases which cannot be properly supported under the 5G regime are proposed. Major key performance indicators (KPIs) to support these use cases are considered. The 6G-related state-of-the-art technologies and standardization activities are discussed in terms of interactivity, intelligence and connectivity. Also, future works to be accomplished for the completion of 6G are shortly stated.

Millimeter Channel Clustering by Self-Organizing Maps With Time-Varying Topological Structure

Cluster-based channel model plays an important role in the fifth-generation (5G) and beyond 5G (B5G) wireless communication systems. A well-designed clustering algorithm can achieve a good compromise between the accuracy and complexity of the wireless channel model. The dependence on prior information of cluster, such as the number of clusters, is a common dilemma of current algorithms. In this article, a self-organizing map with time-varying topological structure (SOM-TVS) clustering algorithm is proposed. First, we combine the locations and weights of the neurons in competition layer and initialize the SOM according to multipath components (MPCs), in which the topology of the SOM is changed with the iterations of the algorithm. Then, a new MPCs’ power weighted Gaussian–Sinc function is proposed to optimize the competitiveness performance of the algorithm. Finally, both the measured and simulated channels in millimeter wave (mmWave) are used to validate the performance of the proposed SOM-TVS algorithm. The SOM-TVS algorithm can perform great effectiveness and robustness based on numerical simulations and experimental validation results. More significantly, the proposed clustering algorithm does not require any prior knowledge of cluster and has a fairly low complexity.

Physical-Layer Network Coding Enhanced Visible Light Communications Using RGB LEDs

Compared with traditional radio frequency (RF)-based techniques, the advantages of wider bandwidth, higher security, and stronger electromagnetic immunity (EMI) capability make visible light communications (VLC) a good candidate technology for the 6th generation (6G) wireless communications. Red, green, and blue (RGB) light-emitting diodes (LEDs) based VLC has become an important research branch due to its low price and high reliability. However, the saturation of photodiode (PD) caused by the ambient background light may seriously degrade the bit error rate (BER) performance of an RGB-VLC system's three spatially uncoupled information streams (i.e., red, green, and blue LEDs can transmit different data packets simultaneously) in practical applications. To mitigate the ambient light interference in point-to-point RGB-VLC systems, we propose, PNC-VLC, a network-coded scheme that uses two LEDs with the same color at the transmitter to transmit two different data streams and we make use of the naturally overlapped signals at the receiver to formulate physical-layer network coding (PNC). The adaptivity of PNC-VLC could effectively improve the BER degradation problem caused by the saturation of PD under the influence of ambient light. We conducted simulations based on the parameters of commercial off-the-shelf (COTS) products to prove the superiority of the PNC-VLC under the influence of four typical illuminants. Simulation results show that the PNC-VLC system can maintain a better and more stable system BER performance under different ambient background light conditions. Remarkably, with 2/3 throughput efficiency, PNC-VLC can bring 133.3% gain to the BER performance when compared with the traditional RGB-VLC systems under the Illuminant A interference model, making it a good option for VLC with unpredictable ambient background interferences.

Distributed Reconfigurable Intelligent Surfaces for Energy-Efficient Indoor Terahertz Wireless Communications

With the fifth-generation (5G) networks widely commercialized and fast deployed, the sixth-generation (6G) wireless communication is envisioned to provide competitive quality of service (QoS) in multiple aspects to global users. The critical and underlying research of the 6G is, firstly, highly dependent on the precise modeling and characterization of the wireless propagation when the spectrum is believed to expand to the terahertz (THz) domain. Moreover, future networks' power consumption and energy efficiency are critical factors to consider. In this research, based on a review of the fundamental mechanisms of reconfigurable intelligent surface (RIS) assisted wireless communications, we utilize the 3D ray-tracing method to analyze a realistic indoor THz propagation environment with the existence of human blockers. Furthermore, we propose a distributed RISs framework (DRF) to assist the indoor THz wireless communication to achieve overall energy efficiency. The numerical analysis of simulation results based on more than 2,900 indoor THz wireless communication sub-scenarios has demonstrated the significant efficacy of applying distributed RISs to overcome the mobile human blockage issue, improve the THz signal coverage, increase signal-to-noise ratios (SNRs), and QoS. With practical hardware design constraints investigated, we eventually envision how to utilize the existing integrated sensing and communication techniques to deploy and operate such a system in reality. Such a distributed RISs framework can also lay the foundation of efficient THz communications for Internet-of-Things (IoT) networks.

Enhancing Secrecy Performance for STAR-RIS NOMA Networks

Simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) is becoming a prospective technology in realizing extremely low power transmission and seamless coverage for the sixth generation (6G) wireless communication era. Motivated by this, we study the secrecy performance of the STAR-RIS assisted non-orthogonal multiple access (NOMA) networks. To be more practical, we assume that all nodes suffer from residual hardware impairments (RHIs). To characterize the performance of the considered network, the analytical expressions of the secrecy outage probability (SOP) for NOMA users over the Nakagami- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$m$</tex-math></inline-formula> fading channels are derived. Meanwhile, the asymptotic behaviors of SOP at high signal-to-noise ratio (SNR) are also studied. The numerical results show that: 1) The existence of the RHIs reduces the secrecy performance of the network under consideration. 2) The increase in the number of configurable elements <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$K$</tex-math></inline-formula> will improve the system secrecy performance.

Channel Prediction Using Ordinary Differential Equations for MIMO Systems

Channel state information (CSI) estimation is part of the most fundamental problems in 5G wireless communication systems. In mobile scenarios, outdated CSI will have a serious negative impact on various adaptive transmission systems, resulting in system performance degradation. To obtain accurate CSI, it is crucial to predict CSI at future moments. In this paper, we propose an efficient channel prediction method in multiple-input multiple-output (MIMO) systems, which combines genetic programming (GP) with higher-order differential equation (HODE) modeling for prediction, named GPODE. In the first place, the variation of one-dimensional data is depicted by using higher-order differential, and the higher-order differential data is modeled by GP to obtain an explicit model. Then, a definite order condition is given for the modeling of HODE, and an effective prediction interval is given. In order to accommodate to the rapidly changing channel, the proposed method is improved by taking the rough prediction results of Autoregression (AR) model as a priori, i.e., Im-GPODE channel prediction method. Given the effective interval, an online framework is proposed for the prediction. To verify the validity of the proposed methods, We use the data generated by the Cluster Delay Line (CDL) channel model for validation. The results show that the proposed methods has higher accuracy than other traditional prediction methods.

On the Efficiency of the Advanced TWA Approach to the 60-GHz Microstrip Antenna Analysis for 5G Wireless Communication Systems

The bandwidth demand in mobile wireless applications has grown at an astounding rate due to the fast evolution of technology, spurring the antenna design fields. The approaches associated with realizing antenna structure at mm-Wave frequency bands for future 5G cellular devices present advantages and disadvantages. This paper exhibits a fast and original approach based on the transverse wave formulation called-up Advanced Transverse Wave Approach (ATWA). A compact 5G patch antenna is designed, measured, simulated, and analyzed in the context of unlicensed mm-wave ISM-band applications. Compared to recently published works, the obtained result analysis proves the efficiency of the proposed method in terms of calculation accuracy, computational efficiency, and peak memory usage and the overall good performance of the proposed antenna.

Intelligent Reconfigurable Surface-Aided Space-Time Line Code for 6G IoT Systems: A Low-Complexity Approach

Intelligent reconfigurable surfaces (IRS) have attracted much attention from both industry and academia due to their performance improving capability and low complexity for 6G wireless communication systems. In this letter, we introduce an IRS-assisted space-time line code (STLC) technique. The STLC was introduced as a promising technique to acquire the optimal diversity gain in 1×2 single-input multiple-output (SIMO) channel without channel state information at receiver (CSIR). Using the cosine similarity theorem, we propose a novel phase-steering technique for the proposed IRS-assisted STLC technique. We also mathematically characterize the proposed IRS-assisted STLC technique in terms of outage probability and bit-error rate (BER). Based on computer simulations, it is shown that the results of analysis shows well match with the computer simulation results for various communication scenarios.

RIS-Assisted Green Secure Communications: Active RIS or Passive RIS?

Reconfigurable Intelligent Surface (RIS) is one of the promising techniques for 6G wireless communications, and recently has also been shown to be able to improve secure communications. However, there is a “double fading” effect in the reflection link between base station and user, thus passive RIS only achieves a negligible secrecy gain in typical communications scenarios. In this letter, we propose an active RIS-aided multi-antenna physical layer secrecy transmission scheme, where the active RIS can amplify the signal actively. Our aim is to minimize the transmit power subject to the constraint of secrecy rate. To solve the non-convex optimization problem, a penalty-based alternating minimization (AltMin) algorithm is proposed to optimize both the beamformer at the transmitter and the reflection matrix at RIS. Simulation results show that active RIS can resist the impact of “double fading” effect effectively, and is more energy efficient than passive RIS.

Study and Analysis of UFMC Technology in 5G Communications

Wireless communication technology plays a significant role in the development of mobile technology. Every user requires their own spectrum. However, spectrum bands are limited. Therefore, the communication system must be efficient. This paper discusses the Universal Filtered Multi-Carrier (UFMC) technology, a new promising technology intended to improve mobile networks in the future. This technology is less susceptible to estimate errors of time shifts and frequency shifts. 5G’s major goals are speed, low latency, Quality of Service, and channel capacity. Physical layer waveform generation must be flexible in order to meet these requirements. Currently, 4G-LTE transmissions are not compatible with 5G technologies because of Out of Band radiation and high Peak to Average Power Ratio (PAPR). A future cellular network could benefit from UFMC. The performance of UFMC is evaluated using Power Spectral Density, PAPR, Signal-to-Noise Ratio, and Bit Error Ratio for 5G wireless communications. It is possible that UFMC will be more efficient and gives better solution.

Design and allocation of low correlated signatures for sequence block-based compressive sensing multiuser detection in massive machine-type communication

Compressed sensing-based multiuser detection (CSMUD) is a promising technique to enable non-orthogonal multiple access (NOMA) for massive machine-type communication (mMTC) in beyond 5G wireless communication systems. CSMUD facilitates grant-free multiple access by jointly detecting the activity and data at the receiver. The performance of CSMUD is predominantly determined by the activity detection, governed by the maximum correlation between the signatures. Sequence block-based CSMUD (SB-CSMUD), an enhanced CSMUD, exploits temporal and spreading diversity to improve the activity detection. In this paper, we propose a three-step approach to design and allocate low correlated signatures and improve activity detection in SB-CSMUD. In the first step, a low correlated random sensing matrix is designed, followed by the designing of low correlated signatures. The designed signatures are then allocated to the nodes according to the traffic pattern of the mMTC. The proposed signatures reduces the maximum correlation by 4.48%, which is further reduced by the proposed signature allocation scheme. The simulation results validate the analysis and show that our proposed scheme significantly reduces the detection error rate (DER) without increasing computational complexity.

A novel beamforming technique using mmWave antenna arrays for 5G wireless communication networks

Millimeter wave (mmWave) multiple-input multiple-output (MIMO) and beamforming technologies are most likely the integral parts and the key enablers of 5G-and-Beyond (5G-B) wireless communication systems. From that perspective, this manuscript proposes an efficient digital beamforming technique for 5G applications. The suggested approach is formulated based on a reliable sampling technique that effectively samples the interference-plus-noise covariance matrix (IPNCM) to construct an efficient projection matrix (PM). The proposed technique is therefore named interference-plus-noise PM (IPNPM) beamformer. Next, a compact-size rectangular microstrip antenna operating at 49.3 GHz having 1.7 GHz potential bandwidth is designed using CST microwave studio. The designed antenna is subsequently used to model a 32-element uniform linear array (ULA) representing a typical 5G base station. The elements of the modeled ULA are then manually fed with the complex-weights generated from the proposed beamformer to produce high-power beams and deep nulls toward the desired and undesired locations, respectively. To further improve the beamformer performance in terms of minimizing radiating power within undesired regions, an iterative sidelobe level (SLL) suppression technique is developed and integrated with the proposed beamformer. The conducted theoretical analysis justifies that the IPNPM beamformer requires less arithmetic operations than the well-known beamforming approaches. To reveal the benefits of the proposed technique, the array radiation pattern based on the proposed beamformer is plotted and compared with those for the three widely used approaches. An intensive Monte Carlo simulation is also carried out in which the IPNPM beamformer performance is systemically compared with the popular approaches based on the output signal to interference-plus-noise ratio (SINR) criterion. The achieved results demonstrate that the proposed approach is superior and surpasses the rival algorithms in terms of generating deeper nulls, enhanced output SINR, and lower execution time. It is also demonstrated that, unlike the existing SLL reduction techniques, the newly developed SLL suppressor reduces the SLLs of the proposed beamformer to a predefined threshold value (i.e., −24 dB) after few iterations.

An imperative role of 6G communication with perspective of industry 4.0: Challenges and research directions

The united nations have set a target of meeting sustainability by 2030 in terms of social, economic, and environmental. Digitalization has proven to be a significant approach to meeting the goal of sustainability. Along with digitalization and Industry 4.0, it was also stated that 6G communication is beneficial for lowering carbon emissions, effective management of natural resources, etc. Based on this motivation, this is the first study to attempt to present the significance of 6G communication from the perspective of Industry 4.0. The fundamental technologies of 6G wireless communications at the physical layer are emphasized, and also discussed enabling technologies of Industry 4.0 for 6G communication in detail. The recommendations and challenges are discussed for future directions. 6G for low earth orbit (LEO) communication and data center operations for 6G network nodes, and 6G network with aerial computing are the recommendation presented in the study. The novelty of study is, it integrates and discussed the sustainability aspect, the vision of the 6G network with fundamental technologies, and Industry 4.0 in detailed. The recommendations and challenges presented in the study motivate the researchers to carry out the study for future research in implementing 6G communication for achieving sustainability with industry 4.0.