As vehicular communications for beyond fifth-generation (B5G) and sixth-generation (6G) is picking up interests from academia and industry recently, more and more research and development have been devoted towards the establishment of vehicular communications for B5G and 6G that is capable of supporting the ever more intelligent transportation systems. One key facilitating the design and improvement

Software-defined networking (SDN) is an emerging technology of efficiently controlling and managing computer networks, such as in data centres, wide-area networks, as well as in ubiquitous communication. In this study, the authors explore the idea of embedding the SDN components, represented by SDN controller and virtual switch, in end-hosts to improve network performance. In particular, the authors

Network coding is a promising technique to improve the throughput and robustness of wireless ad hoc networks. However, the packet-mixing nature of network coding also renders it more prone to pollution attacks. Most existing schemes to combat pollution attacks did not consider the defender's resource limit, nor the trade-off between defensive performance and other metrics such as delay and resource

A beamforming and combining method for a multi-user large multiple-input multiple-output (MIMO) system is proposed, in this study. A transmitter is equipped with a very large number of antennas to serve many users. At the transmitter, a group of antennas is allocated to each user. For a particular group of antennas, a specific beamforming vector is employed at the transmitter for transmission of a

In orthogonal frequency-division multiplexing (OFDM)-based full-duplex (FD) systems, the terminal is allowed to transmit and receive signals simultaneously in the same frequency band. This leads to new challenges to pilot for channel estimation. The conventional pilot design methods are no longer effective for such systems. In this study, the authors propose a new practical pilot design method for

Free space optical (FSO) inter-satellite links could often be non-reliable due to the imperfect line of sight (LOS) links. To achieve more reliable communication, the authors propose hybrid inter-satellite links. However, this leads to new challenges like switching physical (PHY) layers at the satellite's transmitter. In this work, they propose a novel hybrid radio frequency-FSO (RF/FSO) satellite

This study investigates the performance of a cooperative non-orthogonal multiple access cognitive network with imperfect successive interference cancellation under Rayleigh fading conditions. Specifically, the authors consider an underlay cognitive network that consists of a primary transmitter–receiver pair and a secondary system where a source node communicates with two destinations nodes directly

The authors propose an integrated Mach–Zehnder interferometer and diversity combining receiver to mitigate the atmospheric turbulence-induced fading in a millimetre-wave (mmW) radio-over-free-space optics (RoFSO) link. They use a carrier frequency of 28 GHz as recommended for the fifth-generation wireless access networks and consider two optical mmW signal generation schemes, namely double-sideband

In this study, the authors proposed the optimal beamforming (BF) design for multiuser broadcast secure transmission under secrecy outage probability constraint with artificial noise technique. Different from former research papers, their model assumes that different users have different priority and importance. Some users are regarded as main users with a stricter constraint, which make the normal

Simultaneous wireless information and power transfer (SWIPT) is a promising solution for future wireless networks as it provides convenient and perpetual energy supplies to wireless users. This study proposes three new transceiver design schemes in two-way relay networks with SWIPT. Firstly, a transmit power minimisation solution is proposed with an aim to minimise the transmit power while meeting

The acoustic signal transmission over the underwater channel has a limited sum rate and it consumes high power due to the properties of the underwater environment. This study attempts to use the non-orthogonal multiple access (NOMA) technologies for underwater communications. NOMA can be an attractive candidate for underwater communication due to its high spectral efficiency, resistance for carrier

The explosive growth of end devices and mobile applications calls for novel schemes that can enable computation-hungry applications at small end-devices and meet the massive connectivity requirement. Cognitive radio (CR), non-orthogonal multiple access (NOMA) and multi-access edge computing (MEC) are envisioned as the key technologies in fifth-generation and beyond. In this work, the authors introduce

Multi-access edge computing (MEC) has attracted much more attention to revolutionising smart communication technologies and Internet of Everything. Nowadays, smart end-user devices are designed to execute sophisticated applications that demand more resources and explosively connected to the global ecosystem. As a result, the backhaul network traffic congestion grows enormously and user quality of experience

This study presents a multiple-input multiple-output (MIMO) statistical channel model for vehicle-to-vehicle (V2V) line-of-sight (LOS) and non-LOS mobile communication system in a rectangular tunnel environment. In order to improve the V2V communication system performance, the authors introduced the elevation and azimuth angles in three-dimensional modelling based on the original literature. In the

Optimising the coding bit-rates and activity rates of sensor nodes is essential for the functionality and survival of wireless sensor networks as these rates not only affect the amount of information collected by the network, but also affect its power consumption. This study proposes a framework for joint coding bit-rates and activity rates optimisation (CARO) of sensor nodes in wireless visual sensor

Mathematical analyses of wireless systems mostly consider fading and exclude the effect of shadowing since the derivation of performance metrics usually becomes extremely difficult. However, shadowing has to be studied to get better insights about the practical realisations. Therefore, generalised-K distribution has been widely used recently to model the impact of both fading and shadowing. In this

Growing urbanisation has lead to the concept of smart cities. The idea of smart city is realised with the help of internet of things (IoT) devices. The existing cloud services lack the potential to meet the peculiar requirements of IoT devices. IoT devices generate a huge amount of data and demand quick response time. Fog computing can be used to process the IoT tasks since fog nodes are comparatively

In this6study, the channel estimation problem is investigated for a wireless communication system assisted by a reconfigurable intelligent surface (RIS). The RIS thus creates an assistant channel, which has the features of positivity and dominance. Owing to these features, the channel estimation problem is formulated as a constrained residual sum of squares minimisation problem, which differs radically

Channel selection is a challenging task in cognitive radio vehicular networks. Vehicles have to sense the channels periodically. Due to this, a lot of time is wasted which could have been utilised for transmission of data. Employing road side units (RSUs) in sensing can prove to be useful for this purpose. The RSUs may select the channel and allocate it to the vehicles on demand. However, this sensing

This study presents an analysis for evaluating the physical layer (PHY) security performance of a two-hop amplify-and-forward cooperative relaying system employing Alamouti orthogonal space–time block coding (OSTBC) in the presence of an eavesdropper, where the transmit antennas for OSTBC are assumed to be spatially correlated. It is also assumed that the authorised main channels as well as the non-authorised

The conventional carrier-sense multiple access/collision avoidance (CSMA/CA) IEEE 802.11 protocol uses the rigid binary exponential backoff algorithm of the distribution coordination function (DCF) for channel access. The protocol poorly performs under loss by wireless links with high packet error rates and dense networks with numerous collisions from hidden nodes. Furthermore, the scheme is not cognisant

Multiband cognitive radio (CR) signalling allows CR networks to efficiently take advantage of the unused frequency bands. On the other hand, joint spectrum sensing and power allocation in CR systems has been shown to enable higher opportunities for CR transmission. In this work, the authors perform joint spectrum sensing and resource allocation (power and bandwidth) in a multiband CR system. This is

In this study, a binate hop cooperative satellite–terrene link with correlated line-of-sight (LOS) components has been considered. The satellite–terrene link is assumed to follow shadowed-Rician fading. Specifically, higher-order moments of the considered system have been derived. Using the expression of higher-order moments, the expressions of the amount of fading and channel quality estimation index

In vehicle ad-hoc networks (VANETs), the full coverage of roadside units (RSUs) is not necessary with the assistance of dead reckoning (DR) for the RSU-based vehicle localisation. This study proposes an optimisation strategy of RSUs deployment, which seeks an optimal RSU layout ensuring the best localisation accuracy with a minimum number of RSUs. With the assistance of DR, first, the average geometric

Designing a scalable and efficient application layer protocols for the Internet of Things (IoT) environment is an ongoing problem. The constrained application protocol (CoAP) offering RESTful services for IoT devices implements a simple congestion control mechanism. This study proposes and analyses the distance-based congestion control CoAP (DCC-CoAP) for the current state of the network and accordingly

In massive multiple-input multiple-output (MIMO) systems, the channel state information (CSI) feedback enables performance gain in frequency division duplex networks. However, with the increase in the number of antennas, the feedback overhead of CSI will also enhance. To this end, this study addresses the issue of massive MIMO CSI reconstruction using convolutional neural network (CNN), long short-term

Device-to-device (D2D) communication plays a significant role in cellular networks as it can increase the capacity, spectrum efficiency and energy efficiency of the system. However, the large computational complexity of D2D resource management optimisation algorithms creates a serious gap between theoretical design and real-time processing, which leads to the limited use of D2D communication technology

In this study, the authors consider the application of machine learning (ML) models in cooperative spectrum sensing of cognitive radio networks (CRNs). Based on a statistical analysis of the classic energy detection scheme, the probability of detection and false alarm is derived, which depends solely on the number of samples and signal-to-noise ratio of the secondary users. The channel occupancy detection

In this study, the authors review various jamming and anti-jamming strategies in the context of cognitive radios (CRs). The study explores different jamming models and classifies them according to their functionality. Furthermore, a study of jamming detection techniques is provided to enable a CR to identify different jamming signals. Finally, anti-jamming communications are discussed in detail to

Cognitive radio networks (CRNs) are vulnerable to spoofing attacks due to their wireless and cognitive nature. Since the traditional cryptographic authentication can hardly prevent such attacks in CRNs, the physical-layer authentication has been investigated for recent years. To achieve a light-weight physical-layer authentication, a rollout partially observable Markov decision process-based algorithm

Physical layer (PHY) security is an important issue in wireless communication systems. In this study, the authors investigate the interactions between the PHY security performance and the spectrum access technique in a cooperative cognitive radio (CR) network. In the classical spectrum access, if the measured energy on a given subchannel is less than a threshold, the subband is dedicated for CR transmission

In a multi-user cognitive radio network (CRN), mobile or hidden secondary users (SUs) are present. Conventionally, such SUs utilize rigid threshold value (λ) for spectrum sensing (SS). When these SUs perform SS, they receive poor quality signals from primary users. This provokes erratic SS decisions, reduces the involvement of SUs in SS, diminishes the probability of detection ( P d ) and raises miss

In this study, a new network architecture based on the software-defined networking (SDN) approach is proposed for cognitive radio networks (CRNs). The proposed network architecture [software-defined cognitive radio (SDCR)] assumes the responsibilities of network resource management for CRNs and provides a dynamic spectrum management mechanism with an SDN controller. In this way, the dependency of network

Emerging cellular-enabled unmanned aerial vehicles (UAVs) communication poses both opportunities and challenges to the current research of UAV applications. On the one hand, the advanced cellular technologies and authentication mechanisms make significant performance improvements of reliability, security, coverage, and throughput of UAVs possible. On the other hand, the considerably dynamic characteristics

Geometric stochastic method and deterministic ray tracing method are two common methods of modelling massive multiple-input multiple-output (MIMO) channels. The former has high computational efficiency but a large number of input parameters need to be extracted from measurements for different environments. Conversely, the latter is more suitable for a specific environment but consumes a lot of computing

In this study, a new transmitter–receiver approach for high-speed train (HST) downlink orthogonal frequency division multiplexing (OFDM) data transmission and detection in fifth generation (5G) communication systems is proposed. The proposed method uses a new Doppler shift frequency (DSF) estimation method, proposed in this study, to calculate the channel tap DSFs at the HST receiver. These estimated

Localisation is one of the most important services in sensor networks. The impact of the used localisation technique used reflects on wireless sensor network services such as coverage or event detection. Accuracy is considered to be one of the factors that is related to successful network performance in most sensor network applications. Communication ranging is one of the practical applicable technique

Error performance of hybrid subcarrier intensity modulation (hybrid-SIM) in optical free-space satellite downlink has been studied in this work. Bit error rate (BER) is improved by aperture averaging and spatial receiver diversity and it is found out be effective in strong turbulence regime. Subsequently, the reduction in scintillation index has been investigated by implementing a single large receiver

In infrastructure-less scenarios such as rural environments, wild emergency response, military applications and disaster relief, unmanned aerial vehicles (UAVs) are capable of providing enhanced mobile edge computing (MEC) services for ground users. Although small latency is the most important advantage of MEC system, how to provide delay aware scheduling in UAV-enabled MEC system still remains unsolved

In this study, elliptic curve cryptography (ECC) is elected for tenant authentication, data encryption, and data decryption due to its minimum key size. The proposed ECC-based authentication approach allows the authorised person to access private data; it protects different related attacks effectively. To develop more secure data encryption, the authors have combined a nature-inspired optimisation

Cellular systems present one of the most suitable wireless technologies to efficiently serve critical machine-type communications (MTC) that require strict quality-of-service (QoS) guarantees. Therefore, ultra-reliable and low-latency communications is a target use case in the design of the upcoming generations of cellular networks. From the radio resource management perspective, guaranteeing such

Here the intelligent jammer issue is studied. With the rapid development of cognitive radio technology, current cognitive terminals can adaptively or intelligently switch channel by spectrum sensing and decision-making. Most of the traditional jamming methods, such as swept jamming and comb jamming, generally work in a relatively fixed pattern, which are not able to effectively jam the terminals empowered

IEEE concentrates on the development of effective media independent handover (IEEE 802.21 MIH) services. The major aim of IEEE 802.21 MIH is to optimise the handover process to make an uninterrupted handover service with less delay. The handover process is categorised into two types a horizontal and vertical process. Among them, vertical handover (VH) needs parameter optimisation for better performance

The next generation of mobile communication systems is being developed for high-bandwidth mobile networks to accommodate applications with high data rates and low delay requirements such as voice over internet protocol, video streaming, cyber-physical systems and gaming. These applications consume a considerable amount of energy and hence drain the user equipment (UE) battery quickly. Long-term evolution

In this study, the authors study binary decision fusion over a shared Rayleigh fading channel with multiple antennas at the decision fusion centre (DFC) in wireless sensor networks. Three fusion rules are derived for the DFC in the case of distributed M -ary hypothesis testing, where M is the number of hypothesis to be classified. Namely, the optimum maximum a posteriori (MAP) rule, the augmented quadratic

For original partial transmit sequence (O-PTS), the conjugate operations can be applied to achieve the purpose of ameliorating the peak-to-average power ratio (PAPR) performance. But in this way, an observation has been found that some of these candidate signals has the same PAPR value that brings about great redundant computations. Based on this, a low-complexity PTS is put forward to abate the PAPR

As an important positioning source of indoor positioning technology, Wi-Fi signals have attracted the attention of researchers for a long time. Fingerprint positioning can solve the problems caused by non-line-of-sight propagation and multipath effects. To improve the accuracy of Wi-Fi indoor positioning, this study proposes an indoor positioning algorithm based on fine-grained channel state information

Most nodes of Mine Internet of Things (Mine IoT) are powered by batteries, and wireless charging using mobile chargers (MCs) is an effective way to make nodes work sustainably. A novel hybrid charging method combining the controlled and opportunistic MCs (C&O charging) is proposed in this study. Workers (such as the repairmen and gas inspectors) carrying portable chargers are proposed to be opportunistic

Information and communication technology (ICT) is one of the sectors that have the highest energy consumption worldwide. It implies that the use of energy in the ICT must be controlled. A software-defined network (SDN) is a new technology in computer networking. It separates the control and data planes to make networks more programmable and flexible. To obtain maximum scalability and robustness, load

Free space optical (FSO) communication channels are affected by fluctuations in irradiance due to atmospheric turbulence and pointing errors. Recently, a generalized statistical model knows as Málaga ( ) was developed to describe irradiance fluctuations of the beam propagating through a turbulent medium. In this paper, an approximate finite-series probability density function (PDF) for composite turbulence

In today's scenario, underwater wireless sensor network (UWSN) has raised as a most famous research areas for the researchers due to its advancement in the real world. In UWSNs, the sensor nodes sense the environment, and then this sensed information is conveyed to one of the sink node and finally to the base station for processing. It is a known fact that nearly about 70% of the total earth surface

Timing estimation is the most crucial part of the modulation classification and demodulation of burst signals. The traditional methods in classical cooperative communication fail to provide satisfying accuracy in non-cooperative communication. A novel timing estimation method was proposed in this study, which involves a carefully designed optimisation function constituted by piecewise over code period

Since the analysis of cell coverage faces complex environments in unmanned aerial vehicle base station (UAV-BS) systems, general coverage probability in a typical cell is derived to analyse a UAV-BS multi-tier network, and this coverage probability is closely related with power difference among UAV-BSs, two-dimension (2D) and three-dimension (3D) UAV-BS deployment, and general interference fading models

Code-based digital signatures suffer from two main drawbacks: large public key size and slow signature generation. Large public key size is inherent in almost all the code-based cryptosystems and other post-quantum alternatives; however, slow signature generation is due to their specific structure. Most of the current code-based signature schemes are constructed based on Courtois, Finiasz, and Sendrier

In this study, the authors propose a generalised switching protocol (GSP) for increasing the flexibility of energy harvesting (EH) protocol and enhancing the security of amplify-and-forward (AF) multi-antenna relaying system. The proposed GSP-based relaying [generalised switching relaying (GSR)] system is established with target node assisted interference and EH technologies. In phase I, while the

With the development of 5G network and big data and the popularity of mobile intelligent devices, the opportunistic social network has been further developed. At present, several existing routing algorithms based on node similarity use the context information of the node to select the best relay node. However, most opportunistic social algorithms only consider the social properties of nodes and ignore

Beacon-based indoor positioning is popular in recent years. In this work, the authors aim to enhance the positioning accuracy by proposing signal power ranking (SPR) and solving related optimisation-based deployment problem of beacons using wireless communication and Bluetooth 4.0 Bluetooth low-energy network technologies. The authors first adopt grid-based field to be the proposed deployment field

In recent years, orthogonal frequency division multiplexing with index modulation (OFDM-IM) has been proposed due to its extra diversity gain. Specially, OFDM with all index modulation (OFDM-AIM) was proposed, which removed symbol bits and enhanced the diversity order compared to typical OFDM. However, the security issue of OFDM-AIM has not been given full attention. This paper proposes an encrypted

This paper develops new suboptimal antenna selection (AS) schemes, majority based transmit antenna selection/maximal ratio combining (TAS-maj/MRC) and joint transmit and receive antenna selection (JTRAS-maj), in a multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA) network. The impact of the channel estimation errors (CEEs) and feedback delay (FD) on the performance of the network

To alleviate the spectrum scarcity, the unlicensed 60 GHz band has raised increasing concerns due to its continuous large bandwidth. Considering IEEE 802.11ad/ay has already been deployed in this millimetre-wave band, the coexistence issues with new radio-based access to unlicensed spectrum should be weighed when deploying fifth generation (5G) network. Fortunately, the directional transmission on