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Beyond-5G (B5G) technology plays a pivotal role in the next generation of communication infrastructure to support the future Society 5.0, a concept introduced in the 5th Basic Plan for Science and Technology by the Japanese Cabinet to define the long-term growth strategy for reconciling economic development with the resolution of social issues through the promotion of science and technologies. Free-space laser communication is a key element in boosting the data transmission capabilities required for B5G applications. The NICT will complete in 2024 the first fully functional prototypes of a series of miniaturized laser-communication terminals for multiple platforms. These terminals are designed to adapt to a wide range of requirements to address scenarios where laser communications can offer a competitive, enhanced solution compared to existing technologies. This paper provides an overview of these terminals' capabilities and the plans for their functional validation, as well as preliminary data from the first full-system tests. A number of innovations integrated into the terminals are introduced, such as the manufacture of the smallest miniaturized EDFA with integrated HPA and LNA and full space qualification to date, the first-ever integration of a beam-divergence control system in a practical communication terminal, the development of the most compact Tbit/s-class modem prototype documented in the literature, and the smallest gimbal design integrated in a lasercom terminal. Furthermore, this paper outlines the mid-term plans for demonstration in the most significant realistic scenarios, emphasizing the use of High-Altitude Platform Stations (HAPSs) and ultra-small satellites. [ABSTRACT FROM AUTHOR]

In this paper, different concepts of reconfigurable RF-MEMS attenuators for beamforming applications are proposed and critically assessed. Capitalizing on the previous part of this work, the 1-bit attenuation modules featuring series and shunt resistors and low-voltage membranes (7–9 V) are employed to develop a 3-bit attenuator for fine-tuning attenuations (<−10 dB) in the 24.25–27.5 GHz range. More substantial attenuation levels are investigated using fabricated samples of coplanar waveguide (CPW) sections equipped with Pi-shaped resistors aiming at attenuations of −15, −30, and −45 dB. The remarkable electrical features of such configurations, showing flat attenuation curves and limited return losses, and the investigation of a switched-line attenuator design based on them led to the final proposed concept of a low-voltage 24-state attenuator. Such a simulated device combines the Pi-shaped resistors for substantial attenuations with the 3-bit design for fine-tuning operations, showing a maximum attenuation level of nearly −50 dB while maintaining steadily flat attenuation levels and limited return losses (<−11 dB) along the frequency band of interest. [ABSTRACT FROM AUTHOR]

This paper presents the design and investigation of a variable reactance-based RF-MEMS capacitive switch operating on multiple frequency bands in millimetre wave ranges used for B5G applications. The proposed switch has a built-in band switching capability to cover multiple frequency bands in FR-II mmWave band which can provide an inspirational and optimistic platform to tackle 5G and beyond challenges. The novel design utilizes lateral deflections to make and break the device's connection and results in a very low pull-in voltage of < 3 V. The switch operates in different modes maximum up to 9 and switches between multiple frequencies by varying the reactance of the electromechanical structure. These modes are tuned to cover all the bands from n257 to n261, primarily used to provide 5G/B5G services in various countries. The RF performance, voltage requirement, and switching speed of the proposed device are as per the guidelines of the 5G/B5G communication system. The insertion losses are < 0.5 dB, and isolation is > 20 dB over the tuned frequency range (FR-II mmWave) with optimum isolation peaks at 12.1 GHz, 12.9 GHz, 21.2 GHz, 22.2 GHz, 23.5 GHz, 24.8 GHz, 26.1 GHz, and 39.5 GHz. The proposed device features a significant improvement in electromechanical and electromagnetic performance over a wide bandwidth with different structural configurations and thus can be used as an efficient IoT (Internet of Things) frequency reconfigurable device. [ABSTRACT FROM AUTHOR]

Sharing resources through network slicing in a physical infrastructure facilitates service delivery to various sectors and industries. Nevertheless, ensuring security of the slices remains a significant hurdle. In this paper, we investigate the utilization of State-of-the-Art (SoA) Virtual Private Network (VPN) solutions in 5G networks to enhance security and performance when isolating slices. We deploy and orchestrate cloud-native network functions to create multiple scenarios that emulate real-life cellular networks. We evaluate the performance of the WireGuard, IPSec, and OpenVPN solutions while ensuring confidentiality and data protection within 5G network slices. The proposed architecture provides secure communication tunnels and performance isolation. Evaluation results demonstrate that WireGuard provides slice isolation in the control and data planes with higher throughput for enhanced Mobile Broadband (eMBB) and lower latency for Ultra-Reliable Low-Latency Communications (URLLC) slices compared to IPSec and OpenVPN. Our developments show the potential of implementing WireGuard isolation, as a promising solution, for providing secure and efficient network slicing, which fulfills the 5G key performance indicator values. [ABSTRACT FROM AUTHOR]

This paper describes different variants of broadband and simple attenuator modules for beamforming applications, based on radio frequency micro electro-mechanical systems (RF-MEMS), framed within coplanar waveguide (CPW) structures. The modules proposed in the first part of this work differ in their actuation voltage, topology, and desired attenuation level. Fabricated samples of basic 1-bit attenuation modules, characterized by a moderate footprint of 690 × 1350 µm2 and aiming at attenuation levels of −2, −3, and −5 dB in the 24.25–27.5 GHz range, are presented in their variants featuring both low actuation voltages (5–9 V) as well as higher values (~45 V), the latter ones ensuring larger mechanical restoring force (and robustness against stiction). Beyond the fabrication non-idealities that affected the described samples, the substantial agreement between simulations and measurement outcomes proved that the proposed designs could provide precise attenuation levels up to 40 GHz, ranging up to nearly −3 dB and −5 dB for the series and shunt variants, respectively. Moreover, they could be effective building blocks for future wideband and reconfigurable RF-MEMS attenuators. In fact, in the second part of this work, combinations of the discussed cells and other configurations meant for larger attenuation levels are investigated. [ABSTRACT FROM AUTHOR]

This paper presents ReproRun, a flexible and extensible run-time framework for the reconfiguration of functions in field programmable gate array (FPGA) devices used in popular software-defined radio (SDR) platforms. The FPGA devices embed a hardwired or soft processing system (PS) which communicates with the programmable logic (PL) using a standard embedded bus interface. In order to apply a seamless run-time partial reconfiguration, we made use of all the related building blocks, design guidelines, and tools offered by AMD-Xilinx. In ReproRun, each partial bitstream targeting a reconfigurable region (RR) of the PL area comes with its respective firmware (i.e., software functions) that runs on the PS side. Our work guarantees run-time updates of the firmware without interrupting the functionality of other software processes running in the PS or PL, by employing a specialized controller, denoted as Run-timE firmWare reconfIguration contRollEr (REWIRE). The latter leverages the open asymmetric multiprocessing framework (OpenAMP). The partial bitstreams and respective firmware are fetched from a remote location using the trivial file transfer protocol (TFTP). ReproRun can be applied in different FPGA accelerators residing in disaggregated open radio access network (RAN) equipment, adaptive radio access technologies, and Edge servers hosting virtualized functions. [ABSTRACT FROM AUTHOR]

Wireless sensor network (WSN) underpinning the smart-grid Internet of Things (SG-IoT) has been a popular research topic in recent years due to its great potential for enabling a wide range of important applications. However, the energy consumption (EC) characteristic of sensor nodes is a key factor that affects the operational performance (e.g., lifetime of sensors) and the total cost of ownership of WSNs. In this paper, to find the modulation techniques suitable for WSNs, we investigate the EC characteristic of continuous phase modulation (CPM), which is an attractive modulation scheme candidate for WSNs because of its constant envelope property. We first develop an EC model for the sensor nodes of WSNs by considering the circuits and a typical communication protocol that relies on automatic repeat request (ARQ)-based retransmissions to ensure successful data delivery. Then, we use this model to analyze the EC characteristic of CPM under various configurations of modulation parameters. Furthermore, we compare the EC characteristic of CPM with that of other representative modulation schemes, such as offset quadrature phase-shift keying (OQPSK) and quadrature amplitude modulation (QAM), which are commonly used in communication protocols of WSNs. Our analysis and simulation results provide insights into the EC characteristics of multiple modulation schemes in the context of WSNs; thus, they are beneficial for designing energy-efficient SG-IoT in the beyond-5G (B5G) and the 6G era. [ABSTRACT FROM AUTHOR]

In Beyond the Fifth Generation (B5G) heterogeneous edge networks, numerous users are multiplexed on a channel or served on the same frequency resource block, in which case the transmitter applies coding and the receiver uses interference cancellation. Unfortunately, uncoordinated radio resource allocation can reduce system throughput and lead to user inequity, for this reason, in this paper, channel allocation and power allocation problems are formulated to maximize the system sum rate and minimum user achievable rate. Since the construction model is non-convex and the response variables are high-dimensional, a distributed Deep Reinforcement Learning (DRL) framework called distributed Proximal Policy Optimization (PPO) is proposed to allocate or assign resources. Specifically, several simulated agents are trained in a heterogeneous environment to find robust behaviors that perform well in channel assignment and power allocation. Moreover, agents in the collection stage slow down, which hinders the learning of other agents. Therefore, a preemption strategy is further proposed in this paper to optimize the distributed PPO, form DP-PPO and successfully mitigate the straggler problem. The experimental results show that our mechanism named DP-PPO improves the performance over other DRL methods.

Around 2020, 5G began its commercialization journey, and discussions about the next-generation networks (such as 6G) emerged. Researchers predict that 6G networks will have higher bandwidth, coverage, reliability, energy efficiency, and lower latency, and will be an integrated “human-centric” network system powered by artificial intelligence (AI). This 6G network will lead to many real-time automated decisions, ranging from network resource allocation to collision avoidance for self-driving cars. However, there is a risk of losing control over decision-making due to the high-speed, data-intensive AI decision-making that may go beyond designers’ and users’ comprehension. To mitigate this risk, explainable AI (XAI) methods can be used to enhance the transparency of the black-box AI decision-making process. This paper surveys the application of XAI towards the upcoming 6G age, including 6G technologies (such as intelligent radio and zero-touch network management) and 6G use cases (such as industry 5.0). Additionally, the paper summarizes the lessons learned from recent attempts and outlines important research challenges in applying XAI for 6G use cases soon.

Beyond-5G (B5G) technology plays a pivotal role in the next generation of communication infrastructure to support the future Society 5.0, a concept introduced in the 5th Basic Plan for Science and Technology by the Japanese Cabinet to define the long-term growth strategy for reconciling economic development with the resolution of social issues through the promotion of science and technologies. Free-space laser communication is a key element in boosting the data transmission capabilities required for B5G applications. The NICT will complete in 2024 the first fully functional prototypes of a series of miniaturized laser-communication terminals for multiple platforms. These terminals are designed to adapt to a wide range of requirements to address scenarios where laser communications can offer a competitive, enhanced solution compared to existing technologies. This paper provides an overview of these terminals’ capabilities and the plans for their functional validation, as well as preliminary data from the first full-system tests. A number of innovations integrated into the terminals are introduced, such as the manufacture of the smallest miniaturized EDFA with integrated HPA and LNA and full space qualification to date, the first-ever integration of a beam-divergence control system in a practical communication terminal, the development of the most compact Tbit/s-class modem prototype documented in the literature, and the smallest gimbal design integrated in a lasercom terminal. Furthermore, this paper outlines the mid-term plans for demonstration in the most significant realistic scenarios, emphasizing the use of High-Altitude Platform Stations (HAPSs) and ultra-small satellites.

Multi-Access Edge Computing (MEC) reduces latency, provides high-bandwidth applications with real-time performance and reliability, supporting new applications and services for the present and future Beyond the Fifth Generation (B5G). Radio Network Information Service (RNIS) plays a crucial role in obtaining information from the Radio Access Network (RAN). With the advent of 5G, RNIS requires improvements to handle information from the new generations of RAN. In this scenario, improving the RNIS is essential to boost new applications according to the strict requirements imposed. Hence, this work proposes a new RNIS as a service to the MEC framework in B5G networks to improve MEC applications. The service is validated and evaluated, and demonstrates the ability to adequately serve a large number of MEC apps (two, four, six and eight) and from 100 to 2000 types of User Equipment (UE). [ABSTRACT FROM AUTHOR]

The future generation of mobile networks envision Artificial Intelligence (AI) and the Internet of Things (IoT) as key enabling technologies that will foster the emergence of sophisticated use cases, with the industrial sector being one to benefit the most. This survey reviews related works in this field, with a particular focus on the specific role of network softwarization. Furthermore, the survey delves into their context and trends, categorizing works into several types and comparing them based on their contribution to the advancement of the state of the art. Since our analysis yields a lack of integrated practical implementations and a potential desynchronization with current standards, we finalize our study with a summary of challenges and future research ideas. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive network slicing dataset designed to empower artificial intelligence (AI), and data-based performance prediction applications, in 5G and beyond (B5G) networks. The dataset, generated through a packet-level simulator, captures the complexities of network slicing considering the three main network slice types defined by 3GPP: Enhanced Mobile Broadband (eMBB), Ultra-Reliable Low Latency Communications (URLLC), and Massive Internet of Things (mIoT). It includes a wide range of network scenarios with varying topologies, slice instances, and traffic flows. The included scenarios consist of transport networks, excluding the Radio Access Network (RAN) infrastructure. Each sample consists of pairs of a network scenario and the associated performance metrics: the network configuration includes network topology, traffic characteristics, routing configurations, while the performance metrics are the delay, jitter, and loss for each flow. The dataset is generated with a custom network slicing admission control module, enabling the simulation of scenarios in multiple situations of over and underprovisioning. This network slicing dataset is a valuable asset for the research community, unlocking opportunities for innovations in 5G and B5G networks.

Beyond-5G (B5G) aims to meet the growing demands of mobile traffic and expand the communication space. Considering that intelligent applications to B5G wireless communications will involve security issues regarding user data and operational data, this paper analyzes the maximum capacity of the multi-watermarking method for multimedia signal hiding as a means of alleviating the information security problem of B5G. The multi-watermarking process employs spread transform dither modulation. During the watermarking procedure, Gram–Schmidt orthogonalization is used to obtain the multiple spreading vectors. Consequently, multiple watermarks can be simultaneously embedded into the same position of a multimedia signal. Moreover, the multiple watermarks can be extracted without affecting one another during the extraction process. We analyze the effect of the size of the spreading vector on the unit maximum capacity, and consequently derive the theoretical relationship between the size of the spreading vector and the unit maximum capacity. A number of experiments are conducted to determine the optimal parameter values for maximum robustness on the premise of high capacity and good imperceptibility.

The next generation of wireless networks is poised to deliver dependable, extensive, and extremely low-latency mobile broadband communications across various industries. In this regard, reconfigurable intelligent surface (RIS)-aided non-terrestrial base station (NTBS) is crucial for developing three-dimensional (3D) networks that aim to integrate the terrestrial and non-terrestrial infrastructures. The integration of RISs with NTBSs has resulted in additional capabilities to attain faster and more flexible mobile coverage. In this paper, we employ a novel RIS-aided NTBSs with non-orthogonal multiple access in downlink heterogeneous networks (HetNets), in which the RIS is utilized to improve the transmission of signals from multiple NTBSs to ground users (GUs). We aim to maximize the system sum rate (SSR) and energy efficiency (EE) by mitigating inter-cluster and intra-cluster interference. The formulated optimization problem is non-convex due to the joint optimization of NTBS 3D positions, RIS reflection angles, RIS reflection coefficients, and successive interference cancellation among GUs. To address this problem, a modified gray wolf optimization -based meta-heuristic algorithm is proposed. In particular, the original optimization problem is divided into three sub-problems (i.e., RIS reflection angles, RIS reflection coefficients, and NTBS 3D position), which are then addressed alternately using the proposed optimization technique. The novelty of our proposed work is presented by reformulating the distance equations to minimize the distance between the wolves and their prey and enhance the search process’s precision. The simulation results stated that the suggested algorithm outperforms the traditional schemes in terms of both SSR and EE. Furthermore, the results show that incorporating RIS into multi-NTBS HetNets effectively boosts overall performance by improving the channel quality between NTBSs and their respective GUs while reducing inter-NTBS interference.

B5G networks are envisioned to meet higher spectral efficiencies through advanced transmission technologies. Consequently, it is important to comprehend the typical propagation characteristics of wireless communication medium that experience multipath effects, fading, shadowing, and nonlinear distortions. Most of these challenging issues arise under non-line of sight conditions concerning the propagation medium, which deteriorates the quality of the signal received due to uncontrollable channel variations. The recent advances in Intelligent Reflecting Surface (IRS), enable a dynamically alterable wireless environment to achieve flexible reconfigurable channels. The deployment of IRS can evidently bypass the obstacles through smart reflections and shall mitigate channel fading impairments. Motivated by the potentials of the IRS, this paper investigates the performance of IRS-assisted multi-input-multi-output (MIMO) systems to analyze the effect of nonlinear distortions and system adaptation over IID and non-IID Gaussian channel variations. The simulations show the distortion levels with the help of power spectral density for correlated or uncorrelated channel conditions. Furthermore, Monte Carlo simulations are performed to understand the behavior of the wireless system through the analysis of bit error rate (BER) vs signal-to-noise ratio (SNR), Ergodic Channel capacity vs SNR in the presence of IID-Gaussian/ non-IID Gaussian and in-band nonlinear distortions. Additionally, in realistic channel conditions, it is observed that the effect of increasing the number of IRS elements increases the BER performance of ~8dB in both IID and non-IID Gaussian variations. Finally, improvement in the performance of ergodic capacity of 5 bps/Hz has been observed at a fixed SNR of 5dB.

Radio Access Network (RAN) virtualization stands as a pivotal concept in the realm of 5G networks and beyond. It emerges as a viable solution not only to address energy cost concerns but also to optimize material and radio resource management. Despite numerous deployment trials worldwide, a comprehensive realization of Virtual RAN (V-RAN) remains elusive. Current platforms tackle various aspects of V-RAN but encounter numerous limitations. In this paper, we conduct a survey on the progress of RAN virtualization to date and discuss the persisting barriers to its full realization in future mobile radio networks. Initially, we revisit the fundamentals of virtualization and its evolution over recent decades, elucidating the distinctions between Cloud RAN (C-RAN), V-RAN, and Open RAN concepts. Subsequently, we offer an in-depth tutorial on the implementation procedures of V-RAN as per different vendors. Lastly, we shed light on persisting issues within vendor platforms and demonstrate, via simulations, the constraints on their performance concerning supported Base Band Units (BBUs) and devices, as well as coordination among various entities.

In this paper, different concepts of reconfigurable RF-MEMS attenuators for beamforming applications are proposed and critically assessed. Capitalizing on the previous part of this work, the 1-bit attenuation modules featuring series and shunt resistors and low-voltage membranes (7–9 V) are employed to develop a 3-bit attenuator for fine-tuning attenuations (

This paper describes different variants of broadband and simple attenuator modules for beamforming applications, based on radio frequency micro electro-mechanical systems (RF-MEMS), framed within coplanar waveguide (CPW) structures. The modules proposed in the first part of this work differ in their actuation voltage, topology, and desired attenuation level. Fabricated samples of basic 1-bit attenuation modules, characterized by a moderate footprint of 690 × 1350 µm2 and aiming at attenuation levels of −2, −3, and −5 dB in the 24.25–27.5 GHz range, are presented in their variants featuring both low actuation voltages (5–9 V) as well as higher values (~45 V), the latter ones ensuring larger mechanical restoring force (and robustness against stiction). Beyond the fabrication non-idealities that affected the described samples, the substantial agreement between simulations and measurement outcomes proved that the proposed designs could provide precise attenuation levels up to 40 GHz, ranging up to nearly −3 dB and −5 dB for the series and shunt variants, respectively. Moreover, they could be effective building blocks for future wideband and reconfigurable RF-MEMS attenuators. In fact, in the second part of this work, combinations of the discussed cells and other configurations meant for larger attenuation levels are investigated.