Generation Mobile Research Articles

Joint Resource Allocation and Trajectory Design for Multi-UAV Systems With Moving Users: Pointer Network and Unfolding

As an important part of the fifth generation (5G) mobile networks, unmanned aerial vehicles (UAVs) have been applied in various communication scenarios due to their high operability and low cost. In this paper, we investigate a multi-UAV communication system with moving users and consider the co-channel interference caused by the transmissions of all other UAVs. To ensure the fairness, we maximize the minimum average user rate during the observed time by jointly optimizing UAVs’ trajectories, transmission power, and user association. Considering that UAVs can cover a large area for communications, UAVs do not need to move as soon as the users move. Therefore, a two-timescale structure is proposed for the considered scenario, where the UAVs’ trajectories are optimized based on the channel state information (CSI) in a long timescale, while the transmission power and the user association are optimized based on the instantaneous CSI in a short timescale. To effectively tackle this challenging non-convex problem with both discrete and continuous variables, we propose a joint neural network (NN) design, where a deep reinforcement learning based Pointer Network named advantage pointer-critic (APC) is applied to optimize discrete variables and a deep-unfolding NN is used to optimize the continuous variables. Specifically, we first formulate a Markov decision process to model the user association, and then employ the APC network trained by the advantage actor-critic algorithm to address it. The APC network consists of a Pointer Network and a Multilayer Perceptron. As for the deep-unfolding NN, we first develop a block coordinate descent based algorithm to optimize the UAVs’ trajectories and transmission power, and then unfold the algorithm into a layer-wise NN with introduced trainable parameters. These two networks are jointly trained in an unsupervised fashion. Simulation results validate that the proposed joint NN significantly outperforms the optimization algorithm with much lower complexity, and achieves good performances on scalability and generalization ability.

Average Rate Maximization for Mobile STAR-RIS-Aided NOMA System

Simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) has been regarded as a revolutionary technology for the sixth generation (6G) mobile networks. This letter investigates the transmission scheme for mobile STAR-RIS-assisted non-orthogonal multiple access (NOMA) system. Specifically, an uplink average rate maximization problem is solved by jointly optimizing the phase shifts, the channel assignment, and the STAR-RIS’s location for mobile STAR-RIS-aided NOMA system. Particularly, a channel assignment scheme is developed to enhance the performance of NOMA system with multiple users. Furthermore, a successive convex approximation (SCA) method is invoked to address the STAR-RIS location design subproblem and a semi-definite programming (SDP) method is leveraged to solve the phase shift optimization subproblem. Simulation results show that the proposed mobile STAR-RIS-empowered NOMA method achieves better average rate performance than various benchmarking schemes.

<b>Verification of the Applicability of Fifth Generation Mobile Communication Systems to Railway Operations</b>

<b>Verification of the Applicability of Fifth Generation Mobile Communication Systems to Railway Operations</b>

Validation of 5G Use Case Solutions – Simultaneous Assessment of Business Value and Social Acceptance in Early Stages of the Research and Innovation Projects

This article recommends a lean approach when validating next generation mobile technology (5G) use case solutions in research and innovations projects (R&I). This validation should include a simultaneous and iterative assessment of business value and social acceptance beyond the traditional assessment of technological performance. The context studied in the article is R&I projects funded by the European Commission. Here a consortium of academic and enterprise partners jointly develops 5G product and service solutions for different industry verticals. From the literature review we learn that partnerships and ecosystems accelerate innovations as well as the significance of performing the validation already in the initial steps of the innovation projects. Based on a case study of seven completed 5G R&I projects we revealed that lean methodology for development of use case solutions were not applied. Furthermore, the assessment of potential business values from the 5G use case solutions, was postponed to the later stages of the R&I projects, and that assessing the social acceptance of these solutions were absent. After piloting the lean start-up methodology in an ongoing 5G R&I project (5G SOLUTIONS) we found that the partners advocated technological performance, business value and social acceptance to be ranked equally important to successfully validate the 5G use case solutions in the early steps in the innovation process. The two pilots we executed was performed as online workshops with partners from the 5G SOLUTIONS consortium and the media and entertainment vertical. The prototype was presented and feedback from the stakeholders were collected using surveys and interactive software tools. We recommend further studies and pilots of our lean start-up validation methodology in forthcoming 5G R&I projects funded by Horizon Europe for confirmation of our findings and further refinement.

Multiple Antenna Systems in Mobile 6G: Directional Channels and Robust Signal Processing

In mobile communications, the trend since later fourth generation systems has been toward significantly larger numbers of antennas and higher carrier frequencies. This has led to numerous refinements and extensions of the channel models used, to account for newly encountered propagation characteristics. With increasing antenna numbers, the acquisition of channel state information (CSI) becomes more challenging, such that robust multiple antenna signal processing is required to cope with CSI imperfections. This article discusses important wireless channel characteristics and modeling aspects of fifth and sixth generation (6G) mobile, examines how these developments impact corresponding CSI acquisition techniques, addresses recent robust multiple antenna signal processing approaches, and specifically highlights features and potentials of 6G technologies.

6G Vision & Analysis of Potential Use Cases

As an operator driven global organization representing the entire value chain, Next Generation Mobile Networks (NGMN) has a substantial track record in providing industry-wide guidance on the 4th generation of cellular mobile networks (4G) and the 5th generation of cellular mobile networks (5G) development.

Categorization of Mining Materials for Restoration Projects by Means of Pollution Indices and Bioassays

Sulfide mining wastes may lead to severe environmental and human health risks. This study aims to use geochemical and ecotoxicological indicators for the assessment of the ecological risks of potentially toxic elements (PTEs) in the San Quintín mining group to categorize wastes prior to mining restoration. Ecotoxicity was evaluated using crustacean (Dahpnia magna, Thamnocephalus platyurus) and algae (Raphidocelis subcapitata) bioassays. The geochemical and mineralogical results suggested that the mining residues underwent intense weathering processes, with active processes of acidity generation and metal mobility. Total PTEs concentrations indicated that the mining materials were extremely polluted, with Pb, Zn and Cd geoaccumulation index (Igeo) values higher than 5 in more than 90% of the samples. The pollution load index (PLI) showed average values of 18.1, which classifies them as very highly polluted. The toxicity tests showed a higher toxicity for plants than crustaceans, being the highest values of toxicity related to toxic elements (Pb, Cd and Zn), electrical conductivity and to pH. This paper presents for the first time the combination of indices in the categorization of mining waste prior to its restoration. The combination of them has made it possible to categorize the waste and adapt the restoration and remediation procedures.

Open-Access Data and Toolbox for Tracking COVID-19 Impact on Power Systems

Intervention policies against COVID-19 have caused large-scale disruptions globally, and led to a series of pattern changes in the power system operation. Analyzing these pandemic-induced patterns is imperative to identify the potential risks and impacts of this extreme event. For this purpose, we developed an open-access data hub (COVID-EMDA+), an open-source toolbox (CoVEMDA), and a few evaluation methods to explore what the U.S. power systems are experiencing during COVID-19. These resources could be broadly used for research, public policy, and educational purposes. Technically, our data hub harmonizes a variety of raw data such as generation mix, demand profiles, electricity price, weather observations, mobility, confirmed cases and deaths. Typical methods are reformulated and standardized in our toolbox, including baseline estimation, regression analysis, and scientific visualization. Here the fluctuation index and probabilistic baseline are proposed for the first time to consider data fluctuation and estimation uncertainty. Furthermore, we conduct three empirical studies on the U.S. power systems, and share new solutions and findings to address several issues of public concerns. This conveys a more complete picture of the COVID-19 impact and also opens up several attractive topics for future work. Python, Matlab source codes, and user manuals are all publicly shared on a Github repository.

Energy-Efficiency Optimization for D2D Communications Underlaying UAV-Assisted Industrial IoT Networks With SWIPT

The Industrial Internet of Things (IIoT) has been viewed as a typical application for the fifth generation (5G) mobile networks. This article investigates the energy efficiency (EE) optimization problem for the Device-to-Device (D2D) communications underlaying unmanned aerial vehicles (UAVs)-assisted IIoT networks with simultaneous wireless information and power transfer (SWIPT). We aim to maximize the EE of the system while satisfying the constraints of transmission rate and transmission power budget. However, the designed EE optimization problem is nonconvex involving joint optimization of the UAV’s location, beam pattern, power control, and time scheduling, which is difficult to tackle directly. To solve this problem, we present a joint UAV location and resource allocation algorithm to decouple the original problem into several subproblems and solve them sequentially. Specifically, we first apply the Dinkelbach method to transform the fraction problem to a subtractive-form one and propose a mulitiobjective evolutionary algorithm based on decomposition (MOEA/D)-based algorithm to optimize the beam pattern. We then optimize UAV’s location and power control using the successive convex optimization techniques. Finally, after solving the above variables, the original problem can be transformed into a single-variable problem with respect to the charging time, which is linear and can be tackled directly. Numerical results verify that significant EE gain can be obtained by our proposed algorithm as compared to the benchmark schemes.

Dual Pricing Optimization for Live Video Streaming in Mobile Edge Computing With Joint User Association and Resource Management

Mobile live video streaming is expected to become mainstream in the fifth generation (5G) mobile networks. To boost the Quality of Experience (QoE) of streaming services, the integration of Scalable Video Coding (SVC) with Mobile Edge Computing (MEC) becomes a natural candidate due to its scalability and the reliable transmission supports for real-time interactions. However, it still takes efforts to integrate MEC into video streaming services to exploit its full potentials. We find that the efficiency of the MEC-enabled cellular system can be significantly improved when the requests of users can be redirected to proper MEC servers through optimal user associations. In light of this observation, we jointly address the caching placement, video quality decision, and user association problem in the live video streaming service. Since the proposed nonlinear integer optimization problem is NP-hard, we first develop a two-step approach from a Lagrangian optimization under the dual pricing specification. Further, to have a computation-efficient solution and less performance loss, we provide a one-step Lagrangian dual pricing algorithm by the convex transformation of non-convex constraints. The simulations show that the service quality of live video streaming can be remarkably enhanced by the proposed algorithms in the MEC-enabled cellular system.

Securing Age-of-Information (AoI)-Enabled 5G Smart Warehouse Using Access Control Scheme

Low-power wireless sensor networks (WSNs) and Internet of Things (IoT) have great impact for the real-time applications in future 5th generation (5G) mobile networks due to the wireless-powered communication technologies. The Age of Information (AoI) plays a crucial performance metric in an IoT-enabled real-time smart warehouse application, where the freshness of the aggregated data is very important. However, wireless medium communication among the beacon nodes and the user equipments (tracking nodes) gives an opportunity to an adversary not only to eavesdrop the data but also to corrupt the data by means of deleting, modifying or inserting malicious information during communication among the entities involved in the smart warehouse environment. To mitigate these issues, we design a security scheme for AoI-enabled 5G smart warehouse through an access control mechanism, where the secure communication among the beacon nodes and the tracking nodes will take place by mutual device authentication and key agreement process. The fresh data collected at the enterprise cloud is then used for big data analytics for better predictions and analysis, such as optimal device scheduling so that the data becomes very fresh. The rigorous security analysis and comparative study show that the proposed mechanism has significantly better security and comparable communication and computational costs as compared to the relevant schemes. In addition, through the real-time testbed experiments, we show that the proposed scheme is practical in 5G smart warehouse context.

Geological characteristics and resources potential of shale oil in Chang 7 Member of Upper Triassic Yanchang Formation in Fuxian area, southern Ordos Basin, western China

Ordos Basin is rich in shale oil resources. Fuxian area in the southern Ordos Basin is an important area where Sinopec is expected to make a breakthrough in the exploration and development of lacustrine shale oil. To further identify the exploration target of shale oil in Chang 7 Member of Fuxian area, Ordos Basin, this study systematically analyzed the sedimentary characteristics, source rock characteristics, reservoir characteristics, oil-bearing characteristics, fracability and preservation conditions of Chang 7 Member in this area. The results show that: (1) the organic matter abundance of shale in the Chang 7 Member is high, and its type is dominated by type I-II1; the maturity is also relatively high, with Ro generally greater than 0.8% in the central and western parts, which is favorable for the generation and accumulation of shale oil. The development of fractures is pretty low, and thus the structure preservation conditions are relatively favorable. Delta front deposits are mainly developed in the northeastern part, while deep lake - semi-deep lake mudstone and gravity-flow deposits are developed in the western part, and the shale oil types are mainly type II and III. (2) Comparing with the western Ordos Basin, the reservoir in Fuxian area has rapid lateral variation and relatively thin cumulative thickness; the thickness of high-quality shale and maturity are low, resulting in low intensity of hydrocarbon generation and low mobility of oil-bearing saturation. Therefore, there is still a need for further improvement and refinement in the exploration evaluation, effective development and engineering techniques. (3) Integrating sedimentary characteristics with shale oil types, source conditions, oil-bearing properties, mobility, fracability and preservation conditions, it is clarified that the Type II shale oil of Chang 72 sub-,Member in Fuxian area is the current realistic exploration type of shale oil, and its favorable target is located in the development area of delta front in the central part and gravity flow in the western part.

Near-Field MIMO Communications for 6G: Fundamentals, Challenges, Potentials, and Future Directions

Extremely large-scale antenna array (ELAA) is a common feature of several key candidate technologies for sixth generation (6G) mobile networks, such as ultra-massive multiple-input-multiple-output (UM-MIMO), cell-free massive MIMO, reconfigurable intelligent surface (RIS), and terahertz communications. Since the number of antennas is very large for ELAA, the electromagnetic radiation field needs to be modeled by near-field spherical waves, which differs from the conventional planar-wave-based radiation model of 5G massive MIMO. As a result, near-field MIMO communications will become essential in 6G wireless networks. In this article, we systematically investigate the emerging near-field communication techniques. First, we present the fundamentals of nearfield communications and the metric to determine the near-field ranges in typical communication scenarios. Then we investigate recent studies specific to near-field communications by classifying them into two categories: techniques addressing the challenges and those exploiting the potentials in near-field regions. Their principles, recent progress, pros, and cons are discussed. More importantly, several open problems and future research directions for near-field communications are pointed out. We believe that this article will inspire more innovations in this important research topic of near-field MIMO communications for 6G.

THz Channel Sounding and Modeling Techniques: An Overview

As the world warms up to the idea of millimeter wave (mmWave) communication and fifth generation (5G) mobile networks, realization slowly dawns that the data rate, latency, throughput, and other performance metrics that are used to assess a new wireless communication technology will not be enough to support the demands of envisioned futuristic applications. Thus there is an eagerness to further climb up the frequency ladder to use the large swathes of available spectrum in the 0.1 - 10 THz band which is expected to act as the key technology enabler to fulfill the requirements of the sixth generation (6G) wireless communication and possibly even beyond. Channel measurement and modeling are crucial to the design and deployment of future wireless communication systems and researchers across the world are putting their best foot forward to accelerate the process. The present article presents comprehensive assimilation of research efforts in the context of THz channel sounding. A detailed overview of the current channel sounding techniques is first introduced followed by their relevance to THz band channel measurement. An in-house novel channel sounder developed for THz band measurement is also briefly introduced in this context. The paper next provides elaborate dissemination of various measurement campaigns in the band of interest followed by the modeling techniques that are available in the literature and are being adopted for the THz band. Post the description of different challenges and future research directions in the context of sounding, measurement, and modeling the article is concluded.

The effect of 5G policy development on self-rated health among Chinese older adults: A quasi-experimental study

ObjectivesThe Chinese government attaches great importance to the construction of 5th Generation Mobile Communication Technology infrastructure. This study aimed to estimate the effect of the 5G policy development on the self-rated health of older adults in mainland China. MethodsUsing the nationally representative data from the China Family Panel Studies in 2018 and its follow-up in 2020, 2334 participants aged 60 and older were analyzed in our study. We employed the two-way fixed estimator in the difference in difference setting to analyse the SRH of the older adults in the cohort with different development level of the 5G measured by the number of policies, and explore the relative differences before and after the onset of 5G policies. And the heterogeneity and several robustness checks were conducted in the analysis. ResultsAfter the onset of the 5G policies, the probability of older adults self-rating good health increased by 31% for each unit increase in the development level of 5G policies, after adjusting covariates. And there were notable disparities in age group, gender, and living areas. The improving effect of the 5G policies on SRH was intensified in the younger ones aged 65–74 years, the females, and those living in urban areas. ConclusionsOur findings showed that the development of 5G policies has a positive role in the SRH of older adults, indicating the health-promoting effects of technological advances. Considering the heterogeneity, more attention and target measures must be taken to help socio-economically disadvantaged groups avoid the digital vicious cycle.

Super-Broadband Optical Access Networks in 6G: Vision, Architecture, and Key Technologies

The sixth generation (6G) mobile networks are envisioned to provide ubiquitous super-band-width access services in the future. Academia and industry are making efforts to explore 6G technologies, especially enabling technologies of 6G radio access networks (RANs). Meanwhile, as the cornerstone of communication networks, optical fiber networks will continue playing a vital role in the 6G era. Next-generation OANs (NG-OANs), which are regarded as the main force of ultra-gigabit access, can provide users with stable super-broadband services, and are expected to support various super-bandwidth applications, including 3D holographic communication, 8K video streaming services, and so on. 6G RANs and NG-OANs are optional solutions to provide super-broadband access services, and their suitable scenarios to serve are different due to their pros and cons. It is envisioned that 6G RANs and NG-OANs will coexist and develop together in the 6G era. Toward this end, we provide in this article a detailed analysis of the architecture, enabling technologies, applications, and challenges of NG-OANs, and perform some comparisons between 6G RANs and NG-OANs on several critical metrics. After that, we propose a vision for the integrated fiber-wireless access networks supporting super-broadband services, and speculate on some potential challenges ahead.

A Practical Cross-Device Federated Learning Framework over 5G Networks

The concept of federated learning (FL) was first proposed by Google in 2016. Since then, FL has been widely studied for the feasibility of application in various fields due to its potential to make full use of data without compromising privacy. However, limited by the capacity of wireless data transmission, the employment of FL on mobile devices has been making slow progress in practice. The development and commercialization of the 5th generation (5G) mobile networks has shed some light on this. In this article, we analyze the challenges of existing FL schemes for mobile devices and propose a novel cross-device FL framework that utilizes the anonymous communication technology and ring signature to protect the privacy of participants while reducing the computation overhead of mobile devices participating in FL. In addition, our scheme implements a contribution-based incentive mechanism to encourage mobile users to participate in FL. We also give a case study of autonomous driving. Finally, we present the performance evaluation of the proposed scheme and discuss some open issues in FL.

Edge Computational Offloading for Corrosion Inspection in Industry 4.0

The fifth generation (5G) mobile networks are a game changer for the 4th industrial revolution (Industry 4.0). The difficulty of developing vertical applications for mobile networks is however still challenging. This article proposes a new paradigm solution to significantly facilitate deploying network applications (NetApp) closer to the end user and improving the user experience, facilitated by 5G. This new paradigm leverages flexible service onboarding and composition end to end, and computation offloading to a Multi-access Edge Computing (MEC) platform to meet the demanding requirements of the NetApps. A functional prototype is developed and empirical comparison is conducted to validate and evaluate the performance of a corrosion detection NetApp using artificial intelligence (AI) in three different scenarios where the application is hosted. The prototype runs this NetApp over an Unmanned Aerial Vehicle (UAV) connected to a 5G network testbed, and the results offer insights into this performance improvement and elaborates how opting for this NetApp solution can help the industry. In this case, the use of this NetApp can achieve a 55.47 percent reduction in computation time and improve corrosion identification processing time by 25.5 percent.

Formalization and evaluation of EAP-AKA’ protocol for 5G network access security

The end user’s Quality of Experience (QoE) will be improved while accessing services in Fifth Generation Mobile Network (5G), supported by enhanced security and privacy. The security guarantees offered by the Authentication and Key Agreement (AKA) protocols will be depended upon by end users and network operators. The AKA protocols have been standardized for 5G networks, and the Extensible Authentication Protocol (EAP)-AKA’ protocol is one of the main authentication mechanisms that has been specified for User Equipment (UE) and network mutual authentication. This article models the EAP-AKA’ protocol and conducts an extensive formal verification of the EAP-AKA’ protocol as defined in the 5G security standard to determine whether the protocol is verifiably secure for 5G. It provides a security evaluation of the EAP–AKA’ protocol based on the current 5G specifications using ProVerif, a security protocol proof verifier. It also presents security properties that support the security verification, as well as quantitative properties that are used to assess the protocol’s performance. Finally, it compares the EAP-AKA’ and 5G-AKA protocols’ security and performance results.

User-centric base station clustering and resource allocation for cell-edge users in 6G ultra-dense networks

Ultra-Dense Networks (UDNs) have been proposed to meet the ultra-high system capacity and ultra-high user experience rate requirements of sixth generation (6G) mobile networks. However, ultra-dense base stations (BSs) deployment poses challenges for cell-edge users such as BS selection, severe interference, resource allocation, and inter-cell handover. To tackle these obstacles, this paper formulates a joint BS clustering and resource allocation problem for cell-edge users in a 6G heterogeneous UDN system. For efficient resolution, this problem is decoupled into two sub-problems to be solved independently. We first propose a user-centric BS clustering algorithm based on many-to-many matching for the BS clustering problem in the heterogeneous UDN system; This algorithm considers the constraint of the system capacity. A many-to-many stable matching between users and small cell BSs is constructed under the optimization objective of maximizing the achievable user rate. Furthermore, we analyze the effectiveness, stability, convergence, and complexity of the BS clustering algorithm. Given established small cell BS clusters, we also propose a user-centric resource allocation algorithm based on network partitioning. This algorithm accounts for the interference of all users in the heterogeneous UDN system and maximizes intra-sub-network interference while minimizing inter-sub-network interference via a spectral clustering-based sub-network partitioning algorithm. Next, orthogonal allocation of resource blocks (RBs) is implemented within each sub-network, and RBs are spatially multiplexed between sub-networks. Numerical results confirm the benefits of the proposed methods: our algorithms outperform benchmark solutions in terms of the sum achievable system rate, average achievable user rate, and user spectral efficiency.