5G has initiated a strong trend toward network softwarization, which is expected to intensify with 6G. At the core of this shift, Software-Defined Networking (SDN) enables a programmable control plane but also broadens the attack surface. This work examines volumetric random-source Distributed Denial of Service (DDoS) attacks in SDN, where the exploitation of table misses in OpenFlow devices generates massive PACKET-IN floods toward the controller, potentially disrupting flow rule management or even compromising network stability. To address this security issue, an entropy-based detection mechanism is proposed, also introducing a dynamic and network-aware computation of the proposal’s hyper-parameters, such as the entropy threshold and the PACKET-IN message window used to analyse the network behavior. Additionally, a mitigation technique is applied by exploiting the meter table provided by the OpenFlow specification, limiting the impact of malicious entities. Experiments show that the proposed solution adapts to network conditions and attack rates, outperforming static entropy-based approaches that ignore traffic dynamics.

In the new Software-Defined Networking (SDN) paradigm some challenges such as suitable traffic load distribution strategies, which can negatively affect the network performance, are faced. In this paper, a Multi-Resource Aware Load-Balancing strategy exploiting Software Defined Networking (SDN) programmability is presented. Our approach, leveraging the SDN controller, distributes the web requests to a web server cluster according to four metrics: CPU, Memory, Network Traffic, and Response Time of each web server. Through a comprehensive experimental campaign, we evaluated and assessed the advantages of the proposed load-balancing approach against basic methods like random selection and round-robin and also against recent advancements in load-balancing strategies that are considered more sophisticated and intelligent.

Flying Ad-hoc Networks (FANETs) are a key technology for 6G networks due to their flexibility and rapid deployment, but ensuring security remains a challenge. The integration of programmable 6G networks with FANETs offers a promising solution to enhance network security. This paper proposes a resource-aware load-balancing strategy using Software-Defined Networking (SDN) to distribute network flows across drones running a Virtualized Intrusion Detection Function (VIDF). Additionally, a dynamic activation approach is introduced, enabling the SDN controller to quickly activate VIDF functions on drones in a 6G-enabled FANET. Performance evaluations demonstrate the benefits of the proposed strategy.

The integration of mobile sensing into public transportation vehicles offers an interesting opportunity for scalable, real-time environmental data acquisition. This study explores a novel approach in which public transportation vehicles serve as dynamic platforms for atmospheric monitoring, equipped with embedded sensor units capable of measuring key environmental parameters. Data collected on the move is transmitted to cloud infrastructure using cellular communication technologies. The research introduces and evaluates three distinct data acquisition and transmission operational modes, aiming to balance measurement accuracy with energy efficiency. Both GPRS and LTE are employed to assess the impact of network choice on system performance. The main focus of the paper is on quantifying the energy requirements of each configuration, providing critical insights into the trade-offs between communication frequency, data volume, and power consumption. The findings contribute to the development of sustainable, vehicle-based monitoring systems suitable for smart cities and intelligent transport applications.

Vehicular Ad Hoc Networks (VANETs) are increasingly evolving beyond traditional traffic safety applications to support intelligent environmental monitoring across urban and highway settings. As concerns over air pollution, noise pollution, and greenhouse gas emissions rise, utilizing vehicles as mobile sensor platforms offers a promising solution for real-time, largescale environmental data collection. This paper investigates a system in which a vehicle, equipped with an environmental monitoring unit, gathers atmospheric data and transmits it to a cloud server. Three distinct data management strategies are proposed and evaluated, using two communication technolo-gies-GPRS and LTE-to compare their effectiveness. The study focuses particularly on assessing the energy consumption of the overall monitoring system. Experimental results highlight the key differences among the three strategies and the impact of the communication technologies on data transmission efficiency and energy usage.

The convergence of blockchain technology and software-defined networking (SDN) presents a promising solution for enhancing network security. Leveraging the decentralized architecture of blockchain and its inherent security properties, this work proposes a blockchain-based framework to strengthen trust and secure communication among SDN controllers in a multi-domain environment. The framework employs a decentral-ized reputation mechanism based on an adaptive approach that dynamically adjusts reputation parameters based on network status and the average reputation of participating nodes. This system uses the Practical Byzantine Fault Tolerance (PBFT) consensus protocol to implement a reliable process for rewarding and penalizing controllers based on their behavior, thus identifying and excluding potentially malicious nodes. Simulation results confirm that the adaptive reputation metric effectively captures node behavior by incorporating network conditions and node-specific data, leading to a more responsive and precise detection process. This dynamic approach improves detection precision, minimizes false positives, and reduces response delays, making it well-suited for diverse and evolving network environments.

This study explores the integration of Machine Learning (ML) techniques for the classification of traffic signs within simulated vehicular environments. Specifically, the research investigates and compares two training paradigms: centralized learning, enhanced through Transfer Learning (TL) to leverage pre-trained knowledge and reduce training time, and Federated Learning (FL), a decentralized method that allows for collaborative training across distributed nodes. The work involves the implementation and evaluation of two deep learning (DL) models: a classical CNN architecture from existing literature (LeNet-5) and a custom-designed CNN model tailored for vehicular contexts. This study contributes to developing cooperative learning frameworks between vehicles and infrastructure, aiming to enhance traffic safety and efficiency.

The emergence of the SDN paradigm represents a pivotal milestone in the development and realization of programmable networks. This paper explores the severity of the malicious flow rules injection attack over SDN controllers. More specifically, the paper focuses on injecting malicious flow rules with the objective of causing flow rule conflicts as a mean to induce ambiguity in the SDN controller decision-making process and, therefore, diverting the expected behavior of the whole network. Building on these considerations and leveraging a rigorous existing definition of various types of flow rule conflicts, this work proposes CRAD-TPS: Conflicting Rule Attacks Detection through Trust-based Penalty System, a trust-based detection mechanism to identify sources of conflicting flow rules. The obtained results shows the benefits of the proposed detection, which is crucial to allow for a prompt action to restore the expected behavior of the network.

The integration of Software-Defined Networking (SDN) in Flying Ad-Hoc Networks (FANETs) introduces centralized control and programmability, enhancing network flexibility and UAV resource optimization. This study evaluates and compares the performance of SDN-based FANETs using two platforms: ns-3 and Mininet-WiFi. A multi-layer architecture was implemented to analyze network behavior under different scenarios, including single-hop, multihop, multipath, and mesh topologies. Performance metrics such as bandwidth, jitter, round-trip time (RTT), and packet loss were assessed. The results reveal that Mininet-WiFi consistently outperforms ns-3, achieving up to 87% higher bandwidth, 26 times lower packet loss, and significantly reduced jitter and latency. The study highlights key limitations in ns-3, such as excessive packet fragmentation, retransmissions, and high processing overhead due to VXLAN tunneling. Recommendations for improving FANET-SDN emulation, including MTU optimizations, alternative tunneling methods, and enhanced controller configurations, are provided. These findings serve as a foundation for future research on optimizing SDN-based UAV networks for real-world deployments.

In emergency scenarios, the network infrastructure must remain reliable and continuously available to ensure connectivity to people and optimal performance in supporting different types of applications, including real-time services. When terrestrial infrastructure is compromised during emergencies, Flying Ad Hoc Networks (FANETs) can offer a quick and effective solution for re-establishing connectivity in affected areas. The dynamic coverage provided by a swarm of UAVs (Unmanned Aerial Vehicles) during a disaster could be crucial for people inside the affected areas. In high-demand and critical situations, the performance of FANETs may deteriorate due to several factors, including simultaneous user connections, high traffic volumes, limited energy resources of network devices, and interference arising within the same geographic region. To address these challenges, this paper proposes a novel, bio-inspired recruitment algorithm that aims to guarantee good performance of FANETs in energy constrained scenarios by efficiently recruiting UAVs to cover the demand of end users connected to the network. In such a scenario, when additional UAVs can not be reachable using the on-earth network infrastructure and multi-hop routing, the recruiting can be supported through a multi-layer hybrid architecture that integrates CubeSats to forward recruiting requests to potential UAVs located far from the network. This approach not only enhances the connectivity of end users but also ensures that the network can efficiently be adapted to the demands of users in emergency situations. • Design of a multi-layer hybrid CubeSat-UAV network for extending coverage. • A novel bio-inspired recruiting algorithm with a joint metric. • Joint metric: hop number, energy level, recruiting time, bandwidth of FANET nodes.

In this paper, an AI-driven Intrusion Detection System (IDS) in an SDN environment is proposed exploiting the holist view of the SDN controller of the network. In order to detect malicious traffic, the proposed system makes use of Machine and Deep Learning (ML/DL) techniques and, based on a well-known network dataset called CSE-CIC-IDS2018, it trains Decision Tree (DT), Random Forest (RF), and Deep Neural Network (DNN) models. The main task of the proposal is a deep analysis of the network traffic features using two techniques, Pearson's correlation coefficient and the Mean Decrease Impurity (MDI), in order to find the most important features and reduce the dataset size and model complexity guaranteeing optimal system performance in terms of server's response time.

IoT devices are becoming more pervasive and integrated within our everyday lives, and networks of these devices are able to help humans accomplish complex and critical tasks. In such a network, IoT devices cooperate using Machine-to-Machine ($M2M$) communications to carry out such tasks. It becomes vital, therefore, to protect such a type of communication most often carried out by resource-constrained devices that cannot afford the overhead of a standard security protocol such as TLS. In this paper, a security framework for MQTT-M2M communications is proposed, considering a smart food retail shop use case. Specifically, we considered SlowIte, Data Forgery, Man-In-The-Middle, and Dictionary attacks that target the communication among the smart devices of food retail shop, proposing a mitigation method for each of them. To prove the benefits the proposal can provide, in terms of CPU/RAM utilization and network bandwidth consumption, we compared it with the baseline MQTT security standard, i.e. TLS.

This paper introduces an error positioning analysis making use of a proposed cooperative multi-technology localization technique that leveraging WiFi, Ultra WideBand (UWB), LIght Detection And Ranging (LIDAR) signals and an Extended Kalman Filter (EKF) is able to guarantee a more precise positioning estimation and a signal map reconstruction. The analysis of the positioning error aims to show how the quality of the used sensors can affect the values estimated by the filter. In particular, we have considered three different classes of WiFi receiver sensitivity for evaluating how the receiver quality can affect the error positioning estimation. Moreover, we have also varied the number of WiFi emitters giving an indication of the goodness of the proposed approach in respect with other techniques. The numerical simulations are carried out considering a system in which sensors with different quality of sensing are taken into account. The results obtained have shown the greater robustness of the proposed strategy compared to others based on multilateration, especially when dealing with low-quality sensors, that is receiver with bad sensitivity, and with different number of WiFi emitters inside the considered area. It emerges that the adopted approach leads to acceptable results even in the presence of unreliable sensor measurements.

In critical scenarios like natural disasters, the physical infrastructure of the network may be heavily damaged or completely torn down making difficult communications and rescue activities. In such cases, due to their nature, Unmanned Aerial Vehicles (UAVs) are usually employed to provide a temporary support network by forming a Flying Ad-Hoc Network (FANET). However, this network should be carefully monitored and safeguarded to guarantee its stability by deploying network security appliances, like Intrusion Detection Systems (IDSs). In the wake of these considerations, this paper delves into the utilization of IDS functions deployed on UAVs, named IDS-enabled UAVs, in emergencies leveraging the modern Software-Defined Network (SDN) paradigm. Specifically, the study proposes a dynamic approach to promptly activate IDS-enabled UAVs, in an SDN-FANET, responding to network traffic increasing and/or malicious activities taking place within the network. In order to achieve this objective, a Software-defined IDS with UAV Resource Aware Load Balancing strategy – SURA-LB – is proposed and implemented within the SDN controller, leveraging its programmable nature and its holistic view of the network. The SURA-LB strategy equally distributes the load among the set of IDS-enabled UAVs by considering their resources and energy utilization along with the experienced network traffic conditions. Finally, an extensive experimental campaign shows the benefits of the proposed load-balancing strategy in reducing and fairly distributing the workload among the IDS-enabled UAVs outperforming naive and baseline load-balancing strategies like Random and Round-Robin and, therefore, bolstering the resilience and the reliability of the set of IDS-enabled UAVs while the traffic to be monitored and analyzed increases.

In the last decade, the investigation of mobility features has gained enormous significance in many scenarios as a result of the significant diffusion and deployment of mobile devices covered by high-speed technologies (e.g., 5G). Many contributions in the literature have attempted to discover mobility properties, but most studies are based on the time features of the mobility process. No study has yet considered the effects of setting a proper sampling frequency (generally set to 1 s), in order to avoid information loss. Following our previous works, we propose a novel predictive spectral approach for mobility sampling based on the concept of a predictive wavelet. With this method, the choice of sampling frequency is governed by the current spectral components of the mobility process and derived from an analysis of future, predicted components. To assess whether our proposal may yield a helpful method, we conducted several simulation campaigns to test sampling accuracy and obtained results that confirmed our expectations.

A dynamic deployment of Intrusion Detection Systems (IDS) over drone networks exploiting the new Software-Defined Networking (SDN) paradigm in emergency scenarios is proposed. In such scenarios, maintaining network security can be a key element to consider for efficient and reliable communication. Drones equipped with IDS can play a vital role in monitoring and protecting the communication infrastructure in such scenarios. To this aim, a dynamic and time-sensitive deployment strategy for IDS on a fleet of drones is proposed to provide a high degree of fault tolerance regarding network defense. Moreover, a load-balancing strategy enabled by the SDN controller to better distribute the network traffic load to be analyzed by the IDS is designed.

Free Space Optics (FSO) represent a promising technology for secure communications in several types of architectures: from Quantum Key Distribution Networks (QKDNs) to satellite communications. In this paper, in particular, we take into account terrestrial point-to-point laser communications and evaluate the performance in terms of Signal-to-Noise Ratio (SNR) and Bit Error Rate (BER), taking into account different scenarios, that can reflect real situations in which long distances can be reached in a secure way, guaranteeing an acceptable level of BER. So, after a huge campaign of simulations, we would like to let the scientific community know which are the theoretical limits that such kind of communications can reach. We take into account standard telescopes parameters (available today in the market), while configuring several real situations, in function of, for example, bit-rate, visibility, link distance, etc. A brief survey of the existing works is given, then a clearer performance evaluation of terrestrial FSO links is proposed.

Nowadays, mobile computing has become a key component of telecommunication systems, and the Open Systems Interconnection (OSI) layer operations are affected by the effects of node movements along the roads, from the physical to the routing/transport layers. In particular, routing approaches have been investigated from many years, trying to optimize the performance of the whole considered system, under different points of view. In this paper we are focusing the attention on the analysis of the mobility grade trend for a mobile ad-hoc network environment, as well as on the way it can be a-priori known, in order to have the possibility to study how the dynamics of mobile nodes can be described and in-advance known, with a predicted knowledge of nodes stability (in terms of mobility). Our simulations considered mobility in real geographical maps, and the obtained results confirmed the goodness of our proposed study.

The Internet of Things (IoT) growth is exponential and it is providing a massive impact on our lives. It gives the ability to connect any kind of wireless device in a network. The distance between devices can change from a few centimeters to many kilometers. For wide-ranging coverage we need to use Low-Power Wide-Area Networks (LPWANs), and new IoT technologies are emerging such as LoRa. This technology enables energy-efficient wireless communication over exceptionally long distances. In order to be able to evaluate the performance of this type of network, new simulators implementing this technology are increasingly emerging; in fact, several tools and simulators for LoRa technology can already be found online. Of course, there is no simulator that gives the possibility to evaluate the whole protocol stack, but there are different implementations that allow to evaluate different features. This paper has considered the LoRaEnergySim-simulator, written in Python Programming language. It allows the setting up of a simple LoRa network, with a single Gateway (GTW). However, in this paper an extension to the Multi-GTW scenario is presented. This extended-version will support also other features, such as the imperfect SF’s orthogonality and new statistics at device and network levels. Moreover, a performance analysis considering the computational cost when using a Single-GTW or Multi-GTW network will be shown.

In this paper, the proposal of an irrigation system exploiting IoT is provided. The proposed system, based on IoT sensors and smart platforms such as Raspberry PI and Arduino, is able to manage farm operations in term of irrigation. The control of water pumps for irrigation is driven by two important parameters: soil moisture and evapotranspiration. The system uses a Reinforcement Learning approach based on Markov Decision Process in order to learn the right water amount needed by the plants. This approach allows to reduce both water and energy consumption. The proposal has been compared with a conventional irrigation system that normally is based on a soil humidity threshold and takes its decision considering the threshold setting. Conducted experiments show the water and energy saving by the use of the proposed Smart Irrigation system.

A key role in the modern telecommunication networks is played by routing aspects as the great number of works present in literature proves. In particular, in the mobile ad-hoc networks routing is a fundamental aspects because the mobile devices nature and their elevate dynamism. In fact, it is important to have the possibility of finding the minimum overhead for connectivity in the network and, calculate the communication potential through the analysis of different parameters. The focus of this paper is represented by the analysis of the entropy in this type of mobile networks. The entropy gives the possibility of studying and predicting the dynamics of mobile nodes. The knowledge of these aspects can help to optimise some key features of wireless mobile communications, such as nodes stability, channel failures, and routing costs. Many simulation campaigns have been carried out by taking into account the movement of the real nodes, obtaining beneficial results, which confirm the effectiveness of the proposed study.

A novel carrier sense multiple access strategy with collision avoidance (CSMA/CA) balancing contention probability and channel access time is proposed. The approach can be applied to any context where the computational simplicity of the MAC must be preferred to the complexity of the channel access strategy. Our MAC, called Delay-Collision CSMA (DC-CSMA), is a slotted nonpersistent CSMA/CA with nonuniform contention probability distribution, designed to reduce at the same time latency of contenders and preserve a high successful access probability. An utility function aiming at equalizing the effects of these two performance metrics is introduced, and the related theoretical properties and optimal distribution are derived. DC-CSMA is insensitive to the number of contenders and very robust with respect to contention window size, packet length, and impairments such as frame synchronization errors and hidden terminals, and it does not require any adaptive tuning to optimize its performance. Current technologies such as WSN, RFID, IoT devices can benefit from such a simple access technique. The numerical evaluation has been led out considering latency, successful probability and throughput, and DC-CSMA has been compared with other classical strategies such as CSMA with uniformly distributed contention probability, CSMA/$p^{\ast}$and Sift distribution.

In this paper, we focused our attention on the design of an Intelligent Transportation System (ITS) system which offers support to the platooning management to achieve a global optimisation of the groups. In this way, new formations help vehicles to reduce energy consumption exploiting platooning. A novel algorithm based on Grey Wolf Optimization (GWO) to perform the search of the best platoon is considered. We evaluated the system performances of the platoon formation by considering several constraints such as platoon size, platoon speed, average platoon energy consumption. For the analysis of the results, we use the Omnet++ framework for protocol issues and Matlab tools for carrying out algorithm performances.

Mobile Edge Computing (MEC) is a new network paradigm that allows resource management and IT services at the edge of a communication network and, so, closer to the devices guaranteeing low latency and high bandwidth requirements. This characteristic makes MEC paradigm suitable for critical communication services used in collaboration with container-based virtualization and with 5G networks. In this paper, an implementation of a collision avoidance system based on MEC in a VANET environment is proposed. This system makes use of cloud and edge computing and it is able to switch communication from edge to cloud server and vice versa when possible, trying to guarantee the required constraints and balancing the communication among the servers avoiding of overloading edge layer. The simulation results have proved how, in some cases, the MEC-5G combination is the best solution for avoiding collisions in a VANET environment.

UAV stands for Unmanned Aerial Vehicle and it is a flying device characterized by the absence of the pilot on board. Its support in many situations and different applications is able to relieve the human operator thanks to its capacity of having a rapid deployment and quickly performing its action. In order to make its tasks, every UAV/Drone is equipped with a set of on-board sensors specific for each task. One of different applicative fields is the precision agriculture, where, thanks to the possibility of equipping the UAV with on-board cameras, it is able to perform detailed analysis of the health status of the plants intervening suddenly if it is needed. In this paper, coordination protocols applied to the problem of controlling a swarm of UAVs/Drones against parasites attacks to crops has been analysed, studying different approaches in order to measure their performance and costs. One of the problems with these devices concerns the limited quantities of fuel and pesticide. A possible approach to this issue is asking for help to other UAVs/Drones in order to destroy completely the parasites. The idea is to apply the concepts of bio-inspired approach to the recruitment protocols providing performance evaluation in order to give the goodness of the proposal.

The paper proposes a comparison between two different coordination protocols for UAVs management in the agriculture domain. In precision agriculture the presence of parasites or the sudden climatic changes represent an important issue for farmers because of the degradation of crops and cultivation quality. Then, the use of the new technologies such as UAVs devices, the new networks such as FANET and the utilization of new sensors and actuators inside UAVs can represent an important aid to the farmers and the agriculture. An important aspect is, surely, the adequate management and coordination of these new devices in order to plan specific strategies able to support adequately the agriculture humans operators.

Unmanned aerial vehicles are devices able to perform many different tasks that can help human activity in many processes. One of the most important use regards the possibility of giving wireless connectivity to user in a specific area. These new typologies of networks are called Flying Adhoc Network. Their use benefit all those situations of emergency where the traditional communications may have many issues, due to the specific event. Different types of natural disasters (such as climatological, meteorological, hydrological, geophysical) can result in many deaths and many economic damages. In these situations, drones can provide an additional or complementary access network, supporting web services and multimedia traffic, helping people involved in the rescue. Hence, it is clear that the possibility of using a simulator can result in a huge help to the research community. So, in this work, a Flying Ad-hoc Network simulator is proposed, able to simulate different scenarios with different coverage areas. In particular, emphasis is given to new coverage and human mobility models, in order to support more realistic situations. Some simulations have been led out to show how the simulator works.

This paper presents a comparison between five different classifiers (Multi-class Logistic Regression (MLR), Support Vector Machine (SVM), k-Nearest Neighbor (kNN), Random Forest (RF) and Gaussian Naive Bayes (GNB)) to be used in a Convolutional Neural Network (CNN) in order to perform images classification. For our experiments we have used a dataset composed of images of objects belonging to 256 widely varied categories called Caltech 256.

In this paper, the attention is focused on the design of a hybrid platoon system capable of minimising energy consumption in the vehicular environment. In this paper, we focused our attention on the design of a Intelligent Transportation System (ITS) system which offers support to the platooning management to achieve a global optimisation of the groups. In this way, new formations help vehicles to reduce energy consumption exploiting platooning. In this work, we propose a novel algorithm based on Gray Wolf Optimization (GWO) to perform the search of the best platoon. Moreover, in this work we propose a protocol to accomplish platoon tasks. We evaluated the system performances of the platoon formation by considering several constraints such as platoon size, platoon speed, average platoon energy consumption, and so on. For the analysis of the results, we use the Omnet++ framework for protocol issues and Matlab tools for carrying out algorithm performances.

In this paper a simulator for the management of a team of Unmanned Aerial Vehicles (UAVs) and drones has been proposed. This new network is known as Fly Ad-Hoc Network (FANET), and it is a particular type of Mobile Ad-Hoc Network (MANET) but with some specific aspects that allow to provide new services in future generation networks. One of the possible applications is emergency situations or scenario where drones can provide an additional or complementary access networks supporting web services and multimedia traffic. In this paper a simulator for FANET deploying has been proposed providing the possibility to simulate different scenarios with different coverage areas. New coverage model has been included in the features and also interesting human mobility model to support more realistic users mobility. Moreover, additional modules for traffic pattern generation have been implemented to create scenario where mobile users can activate multimedia calls and traffic on FANET. Some simulations have been led out to show how the simulator works.

The work proposes a simulation environment for UAVs management in the agriculture domain.In these last years, new technologies can effectively support farmer to face issues and threats such as parasites and sudden climatic changes that can severely degrade the crop or the quality of the cultivated products.However, to properly manage a UAVs team, equipped with multiple sensors and actuators, it is necessary to test these technologies in order to plan specific strategies and coordination techniques able to efficiently support farmers and achieve the targets.At this purpose, this contribution proposes a simulator suitable for the agriculture domain, where it is possible to set many parameters of this domain of interest.

In wireless networking, the main desire of end-users is to take advantage of satisfactory services, in terms of QoS, especially when they pay for a required need. Many efforts have been made to investigate how the continuity of services can be guaranteed in QoS networks, where users can move from one cell to another one. The introduction of a prediction scheme with passive reservations is the only way to face this issue; however, the deployment of in-advance bandwidth leads the system to waste resources. This work consists of two main integrated contributions: a new pattern prediction scheme based on a distributed set of Markov chains, in order to handle passive reservations, and a statistical bandwidth management algorithm for the reduction of bandwidth wastage. The result of the integration is the Distributed Prediction with Bandwidth Management Algorithm (DPBMA) that is independent from the considered technology and the vehicular environment. Several simulation campaigns were conducted in order to evaluate the effectiveness of the proposed idea. It was also compared with other prediction schemes, in terms of system utilization, accuracy, call dropping, and call blocking probabilities.

Vehicular networking is rapidly growing in the last years, due to its ability of enhancing users everyday-life, in terms of comfort, security and QoS. New services are being implemented and the research activity on the topic is embracing different OSI layers, like the network and application ones. Many efforts have been also given at the PHY layer. In this paper we focus our attention on a new approach for modeling the wireless channel of VANETs communications. In the literature many channel models have been proposed, but most of them work at the bit level or they investigate only some aspects of channel interaction. In this work we provide a high level IEEE802.11p channel model based on Discrete Time Markov Chain (DTMC) modeling, useful in every simulation context. The proposed model is called Markovian Vehicular Channel Model (MVCM) and it is based on the concept of Packet Error Rate (PER) discretization: we do not consider the performance analysis at the bit level, but we derive the proposed model by computing the PER, associated to different observation times. The effectiveness of the proposed idea has been evaluated through a deep campaign of simulations.

In last years, wireless networking is becoming very popular because it is able to satisfy user requests in terms of Quality of Service (QoS); when mobility is present, perhaps, hand-over issues are relevant when hosts change coverage areas during their active sessions. It is very important to mitigate mobility effects, employing an appropriate bandwidth management policy. In our work, we propose two integrated schemes: the first one is based on Markov theory and is aimed at the prediction of mobile hosts movements (in terms of future cells), while the second one is based on statistical theory and is aimed at the minimization of the wasted bandwidth used for passive reservations. So, the proposed Pattern Prediction and Passive Bandwidth Management Algorithm (3P-BMA) is the result of the integration of the Markov predictor and the statistical bandwidth management scheme. 3P-BMA is completely independent on the considered technology, mobility model and vehicular environment. We do not care if the coverage is made by UMTS or WLAN technologies, if hosts are pedestrians or mobile users, etc. Some campaigns of simulation have been led-out in order to confirm the effectiveness of the proposed idea in terms of prediction accuracy, Call Dropping/Blocking probabilities and system utilization.

The utilization of the Return Channel Satellite (RCS) in DVB systems allows a bi-directional communication via satellite. With this particular characteristic, DVB-RCS systems promoted its enormous diffusion in the commercial area and the academic research interest and, in this context, it is very important to test DVB-RCS systems using an efficient satellite channel model. Many channel models have been proposed in the literature, but most of them work at the bit level or they investigate only some aspects of channel interaction. In this paper we present a high level satellite channel model based on Markov Chains (MCs) modeling, useful in every simulation context: the proposed Markovian Satellite Channel Model (MSCM) is based on the concept of windowed observations and the idea is not to analyze a single packet, but fixing an observation window to evaluate the degradation level of the link, computing the PER associated to the specific window. The model has been verified through a deep campaign of simulations, which demonstrate how the introduced error is minimized.

Satellite communications represent an important slice of the global communications sector thanks to their broadcast nature. Unfortunately, TCP used on satellite links suffers from a number of well-known performance issues, especially for high altitude satellites with longer delays. In this paper, a new TCP protocol is proposed. This new protocol arises after a careful study of the various protocols present in literature that try to resolve the typical satellite issues. Our TCP protocol is called Available bandwidth adaptable Transport Protocol (ATP) and it takes the advantages of two TPC protocols proposed in literature: Satellite Transport Protocol (STP) and TCP Jersey. In particular, it consists of a reviewed version of STP protocol with the addition of the TCP Jersey Bandwidth Estimation algorithm called Available Bandwidth Estimation (ABE). In order to show the goodness of the proposed protocol we have performed some comparisons between ATP, STP, TCP Jersey and another TCP protocol called Satellite Communication Transmission Protocol (SCPS-TP).

In last years, wireless networking is becoming very popular because it is able to satisfy user requests in terms of Quality of Service (QoS); when mobility is present, perhaps, hand-over issues are relevant when hosts change coverage areas during their active sessions. It is very important to mitigate mobility effects, employing an appropriate bandwidth management policy. In our work, we propose two integrated schemes: the first one is based on Markov theory and is aimed at the prediction of mobile hosts movements (in terms of future cells), while the second one is based on statistical theory and is aimed at the minimization of the wasted bandwidth used for passive reservations. So, the proposed Pattern Prediction and Passive Bandwidth Management Algorithm (3P-BMA) is the result of the integration of the Markov predictor and the statistical bandwidth management scheme. 3P-BMA is completely independent on the considered technology, mobility model and vehicular environment. We do not care if the coverage is made by UMTS or WLAN technologies, if hosts are pedestrians or mobile users, etc. Some campaigns of simulation have been led-out in order to confirm the effectiveness of the proposed idea in terms of prediction accuracy, Call Dropping/Blocking probabilities and system utilization.

DVB-RCS is an open satellite communications standard allowing a bi-directional communication via satellite. These characteristics certainly promoted its enormous diffusion in the commercial area and the academic research interest. In this context, it is very important to test DVB-RCS systems using an efficient satellite channel model. In the literature many channel models have been carried out, but most of them work at the bit level or they investigate only some aspects of channel interaction. In this work we provide a high level satellite channel model based on Discrete Time Markov Chain (DTMC) modeling, useful in every simulation context. Our model, called Quality Degree-DTMC (QD-DTMC), is based on the concept of Quality Degree (QD) of a given observation windows: the idea is not to analyze a single packet, but fixing an observation window and evaluating the QD of the link, computing the Packet Error Rate (PER) associated to the specific window. The effectiveness of the proposed idea has been evaluated through a deep campaign of simulations.

In wireless networking, users mobility has a heavy impact on QoS parameters and the existing architectures for real-time services with motionless hosts become inadequate for QoS management. In particular Doppler shift and multipath fading introduce some degradations in wireless transmissions. For these reasons, the management of real-time flows and handover events (in terms of bandwidth guarantee and service continuity) when the system is dealing with Mobility Independent Predictive (MIP) services is mandatory, if QoS constraints need to be satisfied. In order to offer a soft QoS increasing the total system utilization, a bandwidth reallocation algorithm has been considered for dynamic resource adaptation, based on wireless channel modeling, in order to take into account the degradations related to the channel state conditions. The main idea of this proposal is the utilization of a pre-reservation phase in the admission control through a Markovian approach, in order to predict the amount of bandwidth needed by a mobile host during its movements among active and passive cells. The performance evaluation of the proposed idea has been made in terms of total admitted/dropped MIP flows, assigned bandwidth and system utilization.

In the last years, there has been a lot of research and development in wireless networking and mobility management. We focus our attention on the management of real-time flows, in particular on the management of hand-over events, in terms of bandwidth guarantee and service continuity when the system is dealing with Mobility Independent Predictive (MIP) services, defined in Integrated Services (IS) for mobile wireless environment. The main idea of this proposal is the utilization of a pre-reservation phase in the admission control through a Markovian approach, in order to predict the amount of bandwidth needed by a mobile host during its movements among the probably visited cells. The performance evaluation of the proposed idea has been made in terms of total assigned bandwidth, system utilization and admitted/dropped MIP flows.

Vehicular communication systems represent one of the most desirable technologies when the safety, efficiency and comfort of everyday road travel need to be improved. The main advantage is the absence of an infrastructure, typical of centralized networks, that makes them very scalable and adequate for highly-variable network topologies. Vehicular Ad-hoc NETworks (VANETs) are able to provide wireless networking capability in situations where no fixed infrastructure exists and the communication among nodes can be either direct or made via relaying nodes, as in the classical ad-hoc networks. In this paper, the attention is focused mainly on the network layer of VANETs, proposing a novel approach to reduce the interference level during mobile transmission, also considering the minimization of path lengths. We propose an interference aware routing scheme for multi-radio vehicular networks and a new metric is also proposed, based both on the maximization of the average Signal to Interference level and on the minimization of the path length of the connection between source and destination. Our solution has been integrated with the AODV routing protocol to design a new MIMO Distance Vector Protocol. NS-2 has been used for implementing and testing the proposed idea, and significant performance improvements have been obtained.

An important suggestion of the standard for DVB-RCS+M is the possibility of using a continuous carrier operation mode in the return channel beyond the classical MF-TDMA mode. In order to realize it a mechanism for switching between these two modalities has to be used. In this paper, after showing the typologies of applications considered in the simulation, a proposal of a novel switching mechanism is presented and the simulation results are reported in order to provide some guidelines to the satellite operators that want to adopt in their satellite system this hybrid mode. The simulation results provide good indications and this study is the base for more depth researches.

The new DVB-S2 standard, introduced by ETSI, is mainly based on three key concepts: best transmission performance, total flexibility and reasonable receiver complexity. The Adaptive Coding and Modulation (ACM) scheme is the tecnique allowing to achieve these main goals. In particular, this tecnique allows to adapt the modulation and code levels, performed at the physical layer, at channel variations in a dynamic way. However, often the others modules, composing a satellite terrestrial terminal, does not take advantage of the ACM potentiality. For this purpose, in this paper we propose an efficient packet scheduling strategy able to operate with the different MODCOD schemes of ACM. In particular, considering ACM policy, Frame efficiency and QoS requirements the scheduling strategy has the main goal of maximizing the overall performances of the system.

In this paper we propose a routing algorithm based on Swarm Intelligence studies. In particular, this algorithm is based on AntNet routing with the extensions of novel metrics for the multi-objective optimization, that are minimum hop count and traffic load balancing. In order to build an optimal solution, the proposed algorithm will make use of ANT agents that consist of probe packets sent on the HAPs network. We have chosen as reference network a HAPs mesh in order to get advantages of the dynamic characteristics of these platforms. In this work we perform a comparison of a classical shortest length path and our algorithm that will try to find the minimum hop path respecting a maximum end-to-end delay bound and an equally distribution of the traffic on the HAPs network.

Deep space communications are an important research line in scientific community. The possibility of performing the communication between earth and other planets is an excitant challenge. The main issue of the communication between planet, called interplanetary (IPN) communication, is the intermittent visibility due to planet movement and the long propagation delay. In order to solve these problems a delay tolerant network (DTN) has been deployed. DTN is an architecture particularly useful in scenarios where very long transmission delays or intermittent connectivity are present, such as IPN network. The routers in DTN perform a transmission mechanism similar to the model of mail transfer protocols or the store-and-forward and it permits to determine a hop-by-hop based messages exchange. Our main contribute in this paper is the introduction of an asynchronous congestion control mechanism on the network that it is not present in the traditional DTN protocol. This control tries to resolve buffer overflow, link saturation and useless retransmission problems in order to better utilize the overall system.

Multimedia communications and, in particular, multicast communications are widely used to distribute multimedia contents. When a certain quality of service (QoS) level must be guaranteed in the multicast tree construction then a Steiner tree problem is obtained, therefore a NP-complete problem must be faced. QoS multicast has a great relevance in the research community because it can offer high performances and better resource allocation. This is relevant in the modern networks, which are composed of wireless networks, wired networks, 3G-4G networks, delay tolerant networks and so on. A better resources allocation permits to have a greater number of connected users. In order to obtain these results it is important to have a multicast tree that can satisfy some QoS requirements. In this work two meta-heurist such as genetic algorithms and simulate annealing algorithms have been considered. Moreover, new procedures and new approaches are proposed in order to obtain better algorithms performances.

Multi-mode satellite terminals are actually the most desired devices on the market, thanks to their flexibility and suitability. A multi-mode radio communication terminal is a terminal allowing two or more transmission mode. In the last few years many research resources have been invested in the study of this new type of terminal In this work, we define a multi-mode terminal as a terminal capable of communicating both with a bent-pipe (BP) satellite and with an on-board processor (OBP) satellite and dynamically setting its transmission parameters (e.g. transmission power and code rate). In order to realize this multi- mode functionality, the most suitable technology is the software defined radio (SDR). The SDR is a set of hardware and software technologies that allow one to obtain reconfigurable architectures for network and wireless terminals. The goal of our work is to plan a satellite system based on digital video broadcast with the return channel satellite (DVB-RCS) standard in which the return channel satellite terminals (RCSTs) are able to adapt it to the channel state, configuring the transmission chain via software, respecting a certain quality of service (QoS) constraint on the packet error rate (PER).

A multi-mode radio communication terminal is a tunable terminal for passing and/or receiving bands in at least two radio communication systems. In the last few years many research resources have been invested in the study of this new type of terminal. This study is intended for a multi-mode terminal is a terminal capable of communicating both with a bent-pipe satellite and with an on-board processor satellite. In the literature different technologies are presented and they can be used to realize the multi-mode capability of a terminal, but, the most suitable technology is the software defined radio (SDR). The SDR is a set of hardware and software technologies that allow one to obtain reconfigurable architectures for network and wireless terminals. The goal of this work is to plan a satellite system based on digital video broadcast with the return channel satellite (DVB-RCS) standard in which the return channel satellite terminals (RCSTs) are able to adapt to the channel state, configuring the transmission chain via software, respecting a certain quality of service (QoS) constraint on the packet error rate (PER).

This paper presents a novel call admission control (CAC) algorithm based on the statistical multiplexing of VBR traffic. The proposed algorithm is called statistical multiplexing based on discrete bandwidth levels of GOP rate (SMDB) because the solution is based on the discretisation of the GOP rate in a set of bandwidth levels and on the time characteristics of discrete bandwidth levels of MPEG sources. SMDB is compared with another statistical CAC based on the normal/lognormal distribution of the GOP rate (SMND). SMDB overcomes SMND in many situations such as high variance around the average video traffic GOP rate of sources and heavy traffic load. The new CAC has been tested in the new generation satellite platform called digital video broadcasting via return channel satellite (DVB-RCS). A high system utilization and multiplexing gain respecting QoS constraints is obtained

The rapid proliferation of the Internet together with the increasing importance of broadband multimedia services has roused the research community's interest, in particular IETF, in QoS traffic. Interesting can be evaluated the QoS architecture and in particular integrated services inside the satellite platform. A multimedia satellite platform called EuroSkyWay has been considered and the IntServ controlled load services (CLS) and the behaviour of the system loaded with controlled load traffic and guaranteed (GS) traffic have been analyzed. The management of CLS is important in order to manage the category the traffic called "better than best-effort" and to guarantee a full interoperation with the terrestrial network. In particular, we have proposed a new way to manage the CLS on satellite systems. The approach is based on reduction of peak bandwidth values of CLS and the increasing of GS request delay tolerance. Different simulations have been outlined and the conformance to QoS parameters for the proposed approach has been verified. Furthermore, the admission control for different values of bandwidth levels declared in satellite admission phase and GS requests timeout have been examined.

This paper focuses on a recently proposed Diff-Serv like architecture called scalable core (SCORE). This one is used in the terrestrial network in order to offer more scalability and deterministic guaranteed services. The integration issues between a scalable terrestrial and a satellite network based on Int-Serv architecture are outlined. The Aggregated RSVP protocol on integrated scalable terrestrial and IntServ satellite network has been introduced in order to guarantee the interoperation between the SCORE architecture and the satellite segment. The system performance in terms of signalling overhead and resource utilization has been set out. The study shows that increasing aggregated bandwidth reservation can improve signalling but can under utilize the terrestrial channel. The satellite network, instead, can improve its static efficiency due to the increased number of calls accepted on the satellite link.