With the surging demand for data-intensive applications, ensuring seamless content delivery in Satellite-Terrestrial Integrated Networks (STINs) is crucial, especially for remote users. Dynamic Ad Insertion (DAI) enhances monetization and user experience, while Mobile Edge Computing (MEC) in STINs enables distributed content caching and ad insertion. However, satellite mobility and time-varying topologies cause service disruptions, while excessive or poorly placed ads risk user disengagement, impacting revenue. This paper proposes a novel framework that jointly addresses three challenges: (i) service continuity-and topology-aware content caching to adapt to STIN dynamics, (ii) Distributed DAI (D-DAI) that minimizes feeder link load and storage overhead by avoiding redundant ad-variant content storage through distributed ad stitching, and (iii) revenue-aware content distribution that explicitly models user disengagement due to ad overload to balance monetization and user satisfaction. We formulate the problem as two hierarchical Integer Linear Programming (ILP) optimizations: one content caching that aims to maximize cache hit rate and another optimizing content distribution with DAI to maximize revenue, minimize end-user costs, and enhance user experience. We develop greedy algorithms for fast initialization and a Binary Particle Swarm Optimization (BPSO)–based strategy for enhanced performance. Simulation results demonstrate that the proposed approach achieves over a 4.5% increase in revenue and reduces cache retrieval delay by more than 39% compared to the benchmark algorithms.

This paper presents “Therapy Reloaded” (TR), an innovative mixed reality (MR) platform designed to enhance rehabilitation for individuals with neurological conditions such as Cerebral Palsy, Multiple Sclerosis, Stroke, and Brain Injury. TR integrates gamification into physiotherapy, transforming traditional therapeutic techniques into engaging experiences. The platform utilises the Meta Quest 3 headset to enable hand tracking, allowing for individualised settings that accommodate for varying degrees of hand mobility. A robust calibration process ensures accurate hand pose recognition, facilitating seamless user input during gameplay. The MR Treadmill game, a core component of the platform, encourages repetitive hand movements through interactive challenges set in a visually enriched environment. Data collected during sessions are relayed to the TR Portal, enabling clinicians to monitor patient progress and adapt gameplay to improve therapeutic outcomes. Allowing rehabilitation goals to be achieved with engaging gameplay, TR aims to improve adherence to physiotherapy, enhance motor control, and ultimately promote better health outcomes for its users.

Satellite Edge Computing (SEC) is seen as a promising solution to content caching onboard by reducing retrieval latency and improving user experience. Deciding content type, number of copies, and where to cache it in a satellite con-stellation remains challenging, requiring careful consideration of many factors, such as satellite coverage, content popularity, and resource constraints. In this paper, we study resource-aware onboard content caching strategies in a multi-layer hierarchical satellite network that includes Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and Geostationary Orbit (GEO) satellites. The primary objective is to design a cache placement strategy that maximizes resource utilization ratio while determining the optimal number of content copies, all within the context of a time-varying network topology that primarly occurs due to the mobility of non-geostationary (NGSO) satellites. We model a novel proximity-based hierarchical hybrid content popularity model and formulate the problem as an Integer Linear Programming (ILP) problem to utilize the resources in a network. To solve the ILP problem, we propose two algorithms: Greedy based Content Cache Placement (G_CCP) and Simulated Annealing based Content Cache Placement (SA_CCP). Extensive simulations demonstrate that both G_CCP and SA_CCP are near-optimal and outperform the benchmark in terms of cache-hit ratio, resource utilization ratio, and cache fetching duration.

Satellite Edge Computing (SEC) is seen as a promising solution for deploying network functions in orbit to provide ubiquitous services with low latency and bandwidth. Software Defined Networks (SDN) and Network Function Virtualization (NFV) enable SEC to manage and deploy services more flexibly. In this paper, we study a dynamic and topology-aware VNF mapping and scheduling strategy within an SDN/NFV-enabled SEC infrastructure. Our focus is on meeting the stringent requirements of mission-critical (MC) applications, recognizing their significance in both satellite-to-satellite and edge-to-satellite communications while ensuring service delay margin fairness across various time-sensitive service requests. We formulate the VNF mapping and scheduling problem as an Integer Nonlinear Programming problem (INLP), with the objective ofminimaxfairness among specified requests while considering dynamic satellite network topology, traffic, and resource constraints. We then propose two algorithms for solving theINLPproblem: Fairness-Aware Greedy Algorithm for Dynamic VNF Mapping and Scheduling (FAGD_MASC) and Fairness-Aware Simulated Annealing-Based Algorithm for Dynamic VNF Mapping and Scheduling (FASD_MASC) which are suitable for low and high service arrival rates, respectively. Our extensive simulations demonstrate that bothFAGD_MASCandFASD_MASCapproaches are very close to the optimization-based solution and outperform the benchmark solution in terms of service acceptance rates.

Non-Geostationary Orbit satellite (NGSO) is an essential element in 5G Non-Terrestrial Networks (NTNs), which can operate either independently or as complementary parts to terrestrial systems to boost the network capacity, coverage and resilience. Due to the highly dynamic topologies, one of the challenges in NGSO is how to harmonize the network virtualized resources to satisfy diverse quality of service requirements in an efficient manner. In this paper, we investigate Virtual Network Embedding (VNE) for integrated NGSO-terrestrial systems while considering dynamic topologies. We propose a Dynamic Topology-Aware VNE (DTA-VNE) algorithm which, given priori information about the network’s evolution over time, can plan the embedding for each Virtual Network Request (VNR) over its lifetime. In a highly dynamic environment, the VNE decision can be varying for different VNRs at the expense of a considerable cost of migrating traffic and reconfiguring resources. The proposed DTA-VNE aims at minimizing this migration cost and thus avoids unnecessary re-mappings. In numerical results, the effectiveness of the proposed DTA-VNE is demonstrated with much lower migration cost than the conventional implementations. We show the benefit of planning for more time slots, in terms of migration cost, and the impact on the computation time, due to the increasing problem complexity. The trade-off between these two performance metrics is studied. Furthermore, we verify the efficiency of DTA-VNE in a MultI-layer awaRe SDN-based testbed for SAtellite-Terrestrial networks (MIRSAT). Finally, the application of DTA-VNE to novel scenarios such as mega LEO constellations is discussed, highlighting the challenges and possible solutions.

Satellite edge computing (SEC) has emerged as a promising technology to deliver network services to remote users. Coupled with software-defined networking (SDN) and network function virtualization (NFV), SEC can provide flexibility, agility, and efficiency when allocating computing and storage resources. However, there still remain a number of technical challenges in terms of fairness and efficiency of the allocation of physical resources in service provisioning, especially in a satellite network with limited resources and dynamic traffic demands. In this paper, we investigate a dynamic virtual network function (VNF) mapping and scheduling in an SDN/NFV-enabled SEC environment to maximize the fairness between competing services in terms of the E2E delay safe margin to enhance the service acceptance rates in the network. We mathematically formulate the VNF mapping and scheduling problem as a nonlinear integer optimization problem, which is NP-hard. In order to effectively solve the problem, this paper proposes a two-stage heuristic dynamic VNF mapping and scheduling algorithm: i) the path selection algorithm returns all possible paths for a given service request with multiple VNFs, which are sorted in ascending order based on their E2E service delay and executed offline, and ii) the dynamic VNF mapping and scheduling algorithm performs online dynamic remapping and rescheduling of VNFs. Finally, numerical results are provided to demonstrate that the proposed algorithm offers a higher service acceptance rate, computing resource utilization efficiency, and higher fairness compared to a benchmark scheme.

Before the advent of High-Throughput Satellites (HTSs), the satellite capacity was not enough to accommodate a large amount of data. Thanks to HTS, beyond 5G networks will boost the cooperation between space, air and terrestrial networks. The coexistence of heterogeneous QoS traffic demands, (e.g., emergency services, In-Flight Connectivity (IFC), Earth Observation Missions (EOMs)), over a dynamic environment, such as Multi-layer satellite-terrestrial networks, made the routing complex to handle. Additionally, due to numerous Inter-Satellite Links (ISLs) and their frequent changes, a testbed with real network emulation is challenging to develop.It is relevant not only to optimize the dynamic routing, but also to emulate the network in a testbed. This allows to consider systems constraints such as communication and technology delays in the most realistic manner. This paper investigates the future coexistence of the mentioned use cases for integrated Non-Terrestrial Networks (NTN)-terrestrial networks. We use Software Defined Networking (SDN) to monitor the substrate network with traffic statistics and apply routing decisions, via traffic handovers, during unexpected situations (congestion, link unavailability), in a reactive manner. Furthermore, we show that, for traditional handovers due to loss of Line of Sight (LoS), the SDN controller manages the procedure proactively to minimize traffic losses.

Non-Geostationary Orbit satellite (NGSO) is an essential element in 5G Non-Terrestrial Networks (NTNs), which can operate either independently or as complementary parts to terrestrial systems to boost the network capacity, coverage and resilience. Due to the highly dynamic topologies, one of the challenges in NGSO is how to harmonize the network virtualized resources to satisfy diverse quality of service requirements in an efficient manner. In this paper, we investigate Virtual Network Embedding (VNE) for integrated NGSO-terrestrial systems while considering dynamic topologies. We propose a Mixed Binary Linear Programming (MBLP) formulation for a Dynamic Topology-Aware VNE (DTA-VNE) algorithm. Given priori information about the network’s evolution over time, DTA-VNE plans the embedding for each Virtual Network Request (VNR) over its lifetime. In a highly dynamic environment, the VNE decision can be varying for different VNRs at the expense of a considerable cost of migrating traffic and reconfiguring resources. DTA-VNE aims at minimizing this migration cost to avoid unnecessary re-mappings. To tackle the exponential complexity of the MBLP, we propose an efficient algorithm based on relaxation approaches (DTA-R) to solve large-scale problems. In numerical results, the effectiveness of the proposed DTA-R is demonstrated with much lower migration cost than the conventional implementations. The trade-off between the computation time and migration cost of DTA-R is studied. Finally, we test DTA-R and the baselines in our developed MultI-layer awaRe SDN-based testbed for SAtellite-Terrestrial networks (MIRSAT) to precisely quantify the packet lost for each migration. DTA-R proved to reduce the packet lost by ~2.5-5% compared to baselines.

The objective is to determine how close an Artificial Intelligence agent is, in comparison to a human player, using only game play images. Identifying Artificial Intelligence agents during game play is typically done through the analysis and collection of bio-metric data, such as keyboard, mouse and other controller interfaces. This document presents a model of an Auto Encoder architecture, with Long Short Term Memory layers. Gradient and Non-Augmented Images have been evaluated and compared. Three distinct personalities of agents are evaluated, human players, a trained Artificial Intelligence agent, and a basic Artificial Intelligence agent. Through testing the Gradient Image augmentation sets present promising results, with the model successfully identifying the human as the closest similarity to the baseline, followed by the trained Artificial Intelligence agent.

This paper studies the Gateway Diversity concept in a satellite scenario, using ONOS, Mininet and OpenSAND. ONOS is used as SDN controller, while Mininet and OpenSAND are used for network emulation and satellite network emulation, respectively. The ability and efficiency of ONOS SDN controller to switch the traffic, for example due to weather conditions, in real-time between two Gateways is presented. Furthermore, a method for allowing automatic instantiation of Gateway and restart of the OpenSAND simulation process promptly is analyzed. Finally, simulation results are shown for the evaluation of these technologies.

Unmanned aerial vehicles (UAVs) have opened up numerous opportunities in terms of connectivity, especially in the context of realizing the vision of ubiquitous connectivity for 5G and beyond (B5G). The ease of mobility makes the UAV base stations (UAV-BSs) a viable candidate for providing `on demand' services to the users. Moreover, viewing the spectrum crunch experienced by traditional cellular networks, the UAV-BSs can share the burden of providing connectivity. UAV-BSs can open up several business opportunities for mobile network operators (MNOs). In this paper, we propose an open market model, where a UAV-BS has the opportunity to establish a link with a terrestrial BS (TBS) of an MNO that provides the best connectivity and offers a lower price. A distributed model is considered where the decision making power lies with the UAV-BS. The TBS-selection problem is modeled as an integer linear programming problem, where we compare the performance of the Greedy heuristic algorithm (GHA) and the backtracking algorithm (BA) to solve our selection problem. We also incorporate an energy prediction model which impacts the selection criteria. We analyze the performance GHA and BA algorithm by presenting a tradeoff between the two algorithms in terms of accuracy of TBS selection and convergence time.

The wireless communication is an integral part of the society, however, wireless network infrastructure may not fully function during post-disaster wireless network scenario in which we need wireless services even more than normal circumstances. In such post-disaster scenarios, the base stations (BS) could possibly be dysfunctional or overloaded by an excessive number of user calls or data, whereas user terminals are likely to be partially connected to or fully isolated from the BS radio signals. In this paper, we study the network behavior during the post-disaster when BSs undergo the thinning process due to the damage to the network infrastructure. During network recovery phase, we also study the network performance when new temporary BSs are distributed which will bring the network into BS superposition phase. Furthermore, Device-to-Device (D2D) assisted cellular communication helps to increase the link level network connectivity which is highly appreciated during post- disaster network scenario because the network coverage is more desirable than the network throughout in such cases. We also present the analytical study of D2D and cellular communication and show that it will effectively increase the network coverage which may ultimately save many lives during the golden hours of post-disaster phase.

Interference is identified as a critical issue for satellite communication (SATCOM) systems and services. There is a growing concern in the satellite industry to manage and mitigate interference efficiently. While there are efficient techniques to monitor strong interference in SATCOM, weak interference is not so easily detected because of its low interference to signal and noise ratio (ISNR). To address this issue, this paper proposes and develops a technique which takes place on-board the satellite by decoding the desired signal, removing it from the total received signal and applying an Energy Detector (ED) in the remaining signal for the detection of interference. Different from the existing literature, this paper considers imperfect signal cancellation, examining how the decoding errors affect the sensing performance, derives the expressions for the probability of false alarm and provides a set of simulations results, verifying the efficiency of the technique.

During the past years, a dramatic increase of peripheral self organised autonomic networks interworking with the traditional infrastructure networks has been highly noticed. Mobile Ad-Hoc Networks (MANETs) have become an interesting topic for research because of their independent nature in terms of network infrastructure and can play a vital role in future Internet communication. A lot of effort has been made in designing efficient routing protocols for MANETs, mainly because of their unique characteristics, such as dynamic topology, high mobility and limited bandwidth. In this paper we evaluate the performance of our Multipath-ChaMeLeon (M-CML) routing protocol and compare to other proactive protocols; Optimised Link State Protocol (OLSR) and Destination-Sequenced Distance Vector (DSDV). For this reason, we have considered 2 different scenarios for MANETs by varying the number of nodes and speed values using the NS-3 simulator. The Quality of Service (QoS) metrics we have taken into account are: packet delivery ratio, end-to-end delay, normalised routing load and energy consumption. The acquired results indicate that M-CML routing protocol reduces the effects of unstable communication links, while at the same time improves the performance of the network.

In conventional cognitive radio systems, the secondary user employs a “listen-before-talk” paradigm, where it senses if the primary user is active or idle, before it decides to access the licensed spectrum. However, this method faces challenges, with the most important one being the reduction of the secondary user’s throughput, as no data transmission takes place during the sensing period. In this context, the idea of simultaneous spectrum sensing and data transmission is proposed. This paper studies a system model where this concept is obtained through the collaboration of the secondary transmitter with the secondary receiver. First, the secondary receiver decodes the signal from the secondary transmitter, removes it from the total received signal, and then carries out spectrum sensing in the remaining signal in order to determine the presence/absence of the primary user. Different from the existing literature, this paper considers the imperfect signal cancellation, evaluating how the decoding errors affect the sensing reliability, and derives the analytical expressions for the probability of false alarm. Finally, numerical results are presented illustrating the accuracy of the proposed analysis.

Multiple sclerosis is a chronic and variable disease in matters of symptoms, clinical course and outcome. The ultimate goal of currently used drugs and therapeutic strategies is the control of disease activity and the delay of the ongoing disability. During the last decades, a number of disease-modifying drugs (DMDs), all products of advanced biotechnology are being used. However, these DMDs are yet partially effective since the ongoing disability progression may hardly be prevented. There is growing evidence that these DMDs might be more effective if more accurate monitoring of the disease itself throughout a period of time might be available. In the new era of MS treatment and on the basis of our current knowledge about MS management, it became pretty clear that the overall therapeutic strategy should always be scheduled on strictly individualized basis. To this, MS patients should be encouraged to take control over their own disease and collaborate more effectively with their doctors. The advent of the IoT (Internet of Things) and 5G mobile technologies can support patients in this direction. Since a snapshot of the overall patient's condition during a regular follow-up visit may not represent the every day reality of the patient, the advice given under these conditions may not be that effective. However, if hard data on the patient's motoric and cognitive performance were available “theragnostics” might be much more effective and efficient and a typical flare-up of the condition might be recognized much earlier - or even anticipated. Health 4.0 is the translation of Industrie 4.0 design principles into the health domain [36]. Health 4.0 is based on the utilization of the Internet of Things (IoT) and the use of cyber-physical systems to connect the physical and the virtual world. The use of smart pharmaceuticals bio-sensors and cyber-physical systems in the management of MS could optimize the accuracy and allow for a precise mapping of symptoms over time which is an inevitable prerequisite for personalization of care. Ideally captured data would be processed in real time in order to flag problems up to the care team and on an individual basis anticipate motoric and / or cognitive deficits in an attempt to compensate for neurological deficits. 5G networks are expected to provide the infrastructure and ease in supporting various parameters recording on a real time basis. Relevant clinical studies may further highlight the need of information communication technology in MS management, thus contributing to the overall improvement of patent's quality of life (QoL). This is an absolute necessity for a variable, fluctuating and largely unpredictable disease such as MS.

This paper presents Multipath-ChaMeLeon (MCML) as an update of the existing ChaMeLeon (CML) routing protocol. CML is a hybrid and adaptive protocol designed for Mobile Ad-Hoc Networks (MANETs), supporting emergency communications. M-CML adopts the attributes of the proactive Optimized Link State Protocol (OLSR) and extends it so as to implement a multipath routing approach based on the Expected Transmission Count (ETX). The paper substantiates the efficiency of the protocol through a simulation scenario within a MANET using the NS-3 simulator. The acquired results indicate that M-CML routing approach combined with an intelligent link metric such as the ETX reduces the effects of link instabilities and enhances the network performance in terms of resiliency and scalability.

We propose the use of a secure topology discovery scheme, based on certificate-less public key management, as part of a proposed secure version of the Neighbourhood Discovery Protocol (NHDP) for Mobile Ad-Hoc Networks. We provide an initial evaluation of the computational cost of sending secure HELLO messages, based on an Android app deployed within a small test-bed environment.

Clustering sensor nodes is an effective method to enhance network coverage and prolong network lifetime. In this paper we propose EAAFC (Energy Aware and Address Free Clustering), a clustering mechanism that analyses communication energy consumption and the impact of node failures on networks with different densities. The proposed algorithm aims at clustering nodes into groups with minimum number of cluster heads. EAAFC does not require global addressing or time synchronization to perform. Evaluation results show that EAAFC prolongs network's lifetime while improves network coverage.

Cognition in radio communication is a valuable means of improving spectrum utilization and can contribute to reducing energy consumption in wireless communication systems. This paper proposes a power control scheme using spectrum hole lifetime to diminish cognitive radio energy consumption. The secondary users' transmission power level will be adapted in different licensed channels subject to the channel characteristics, interference power constraint and idle channel lifetime. The power control scheme is evaluated in a multi-licensed channels environment. The simulation results confirm that the proposed scheme considerably improves the efficient use of energy at the cognitive user during the secondary use of licensed channel.

The self-organised nature of Mobile Ad hoc Networks (MANETs) makes it a suitable candidate for rescuer communication in disaster scenarios. This paper presents a model basis for supporting the design of hybrid and adaptive routing protocols such as ChaMeLeon (CML). A size threshold point between proactive and reactive routing approaches is established using a probabilistic analytical model using dimensional cardinalities of the effective operation area, called the critical area (CA). CML adapts its routing behaviour according to the network size in order to improve overall routing efficiency while preserving acceptable quality of service (QoS) relative to well known protocols that are Ad hoc On-demand Distance Vector (AODV) routing and Optimized Link Sate Routing (OLSR). These are also constituents of the reactive and proactive routing parts of CML respectively. The Evaluation section contains simulation results to support our analytical models and to compare the performance of CML with state of the art MANET routing protocols considering disaster scenarios with free space as well as obstacle prone environments also used to establish our models. We finally discuss the results and present some conclusions.

The autonomous nature of Mobile Ad hoc Networks (MANETs) makes them suitable for the support of extreme emergency rescuer IP communications for next generation networks. A major hurdle towards the deployment of emergency MANETs (eMANETs) is the design of a distributed routing protocol that can adapt to its highly dynamic topology where the number of nodes in the network frequently varies. This paper presents ChaMeLeon (CML), a hybrid and adaptive routing protocol designed to adapt to the rapid topological changes in extreme emergency MANETs (eMANETs) when operating within a predefined disaster area. CML adaptively changes its routing behavior according to the number of nodes in the network, so that it can provide a more efficient routing approach than purely proactive or reactive routing protocols for varying size networks. The protocol can operate in one of three routing phases which are the reactive phase (R-phase) for large networks, proactive phase (P-phase) for small networks and oscillation phase (O-phase) for phase transitions based on a network size threshold. This threshold is determined using simulation based performance statistics of the purely reactive or proactive routing protocols. We then present results to demonstrate that CML outperforms its routing counterparts over the simulated range of network sizes and particular critical area.

In many extreme emergency cases such as forest fires or tube terrorist attacks, the rescuers have difficulty using traditional legacy networks due to destruction or collapse of the infrastructure in such events. We use the term emergency Mobile Ad hoc NETworks (eMANETs) in order to describe Next Generation Networks (NGNs) which are deployed in emergency cases. The security of these networks is critical. Especially secure routing is important given the fact that potential attackers aim to disrupt the appropriate operation of the routing protocol within an eMANET. In this paper we propose a game theoretic approach called AODV-GT (AODV-Game Theoretic) and we integrate this into the reactive Ad hoc On-demand Distance Vector (AODV) routing protocol to provide defense against blackhole attacks. AODV-GT is based on the concept of non-cooperative game theory. AODV-GT outperforms AODV in terms of malicious dropped packets when blackhole nodes exist within the eMANET. Our simulations were implemented using the network simulator ns-2.

One of the key research issues in wireless systems is how to improve the system capacity. MIMO has been proven as an effective method to achieve this. Previously, the focus of MIMO-OFDM research in high performance metropolitan area network (HIPERMAN) systems was on space time coding (STC) and beamforming. Recently, multi-user detection (MUD) has emerged as a novel approach in MIMO-OFDM-based HIPERMAN systems. In this paper, we have proposed a new MAC design, which includes the new and flexible MAC frame structure and an efficient dynamic resource allocation algorithm, in order to accommodate the MUD techniques in uplink transmission in HIPERMAN systems. The performance of the new MAC design has been evaluated via simulation means. The simulation results show that the new MAC design based on MUD can significantly increase the system capacity.