Future 6G networks will be called upon to support increasingly sophisticated applications based on the massive use of Artificial Intelligence (AI). This poses serious challenges to mobile devices that do not have adequate computational and energy capacity to support the effective execution of AI tasks. According to the emerging Split-AI paradigm, 6G networks can help user devices to perform complex AI tasks by distributing and executing a Neural Network (NN) collaboratively among different processing nodes, including network nodes in the 6G User Plane (UP). However, the extent to which these offloading mechanisms can improve the end-to-end latency of AI tasks is limited by the computational resources available in an operator’s network. The presence of Graphical Processing Units (GPUs) in some elements of the UP can certainly help, but it is necessary to quantify the cost of the task acceleration in terms of increased energy consumption entailed by GPU usage. In this work, we study on the example of Split-AI, the impact of GPU acceleration on inference time and energy consumption. Thereby, we demonstrate that GPU inclusion can reduce the latency induced by the DNN computation by up to 90%, with moderate energy consumption increase of 22% at most.

The growing reliance on digital connectivity has made Internet Service Provider (ISP) networks a critical component of modern society, yet they remain a prime target for cyber threats. In recent years, cyberattacks against ISPs have increased in scale and sophistication, posing severe risks to national security, economic stability, and user privacy. The advent of in-network computing and programmable data plane presents a paradigm shift in network security, offering the flexibility to define, modify, and optimize packet processing logic dynamically. Among these advancements, the P4 programming language plays a crucial role, allowing network operators to implement fine-grained traffic monitoring directly within network devices. By leveraging in-network computation, P4 facilitates real-time anomaly detection, making it a powerful tool for mitigating Distributed Denial of Service (DDoS) attacks. However, orchestrating security functions across a distributed network of P4 switches remains a challenge, requiring an efficient and scalable deployment framework.In this paper, we present an open-source orchestration platform for managing and deploying P4-based security programs to enable real-time DDoS detection. Our solution leverages dynamic programmability to enhance network security. By integrating a novel queue monitoring mechanism directly into the data plane, our approach enables the collection of fine-grained network performance metrics in real-time, facilitating faster and more precise attack detection and mitigation. The proposed framework is highly scalable and adaptable, strengthening ISP networks against evolving cyber threats.

The next generation of high-accuracy positioning services is required to satisfy the sub-meter accuracy level for more than 95% of the network area, including indoor, outdoor, and urban deployments. In this vein, inter-agent measurements appear to provide additional position information and, hence, have the capacity to boost localization accuracy . This paper researches cooperative positioning techniques by means of device-to-device (D2D) and reconfigurable intelligent surfaces (RIS) technologies leveraging received signal strength (RSS) based ranging. We estimate the maximum capacities of the positioning systems in terms of accuracy through the Gaussian noise model, proposed universal theoretical distance-dependent noise model, and empirical noise model. We also evaluate the positioning error achieved by combining two or more technologies. Numerical results reveal the use cases advantageous for RIS- and D2D-aided localization. Then, based on the results, valuable guidelines are derived on the optimal sensor fusion metric – median – that minimizes the mean error of the cooperative localization.

Telecommunication technologies are important enablers for both digital and ecological transitions. By offering digital alternatives to traditional modes of transportation and communication, they help reduce carbon footprints while improving access to fundamental services. Particularly in rural and remote areas, telecommunications facilitate access to education, healthcare, and employment, helping to bridge the digital divide. Additionally, telecommunications can promote sustainability by supporting renewable energy usage, gender equality, and circular economies. However, defining the role of telecommunications in sustainability remains complex due to the historical focus on performance rather than long-term societal goals. Given the significance of this theme, this paper aims to provide the reader with a deeper look at the concept of sustainability within the telecommunications sector by examining relevant initiatives and projects. It reviews the major approaches for measuring sustainability and outlines practical approaches for implementing these assessments. Furthermore, the paper explores the proposed network architectures that incorporate Key Value Indicators and discusses major technologies in this area, such as Network Digital Twins and Intent-Based Networking. Through this analysis, the paper aims to contribute to creating sustainable telecommunication networks and broader industries.

Recent advances in hardware and software technologies have led to the design of many pervasively distributed IoT devices that can generate/consume data and manage multiple sensors and actuators, paving the way for new applications and services. However, these new features, at the same time, can easily become an enticing “grab point” for attackers, unlocking a newer and larger attack space and exposing things to greater vulnerability. In this perspective, the objective of this document is the improvement of the IoT publish/subscribe architecture and the MQTT protocol with more scalable and dynamic additional security mechanisms, which can provide end-to-end security while reducing overhead and traffic load on the broker. Building upon our prior published research, the proposal further extends and advances the concept of “security layers” between which devices with priority-aware topics can easily switch to reduce protocol overhead and increase flexibility. Each topic has associated security characteristics that clients negotiate with each other, thus saving the broker from managing any security primitives. The proposed security mechanism called Dynamic and Lightweight Security over Topics MQTT (DLST-MQTT), is compared with the standard MQTT and TLS-MQTT in terms of bandwidth consumed, CPU, and RAM usage. Additionally, security levels with relevant scores are defined, and two security update procedures taking advantage of topic priorities are designed and evaluated. • A lightweight ECC-based security reduces the overhead for constrained IoT devices. • End-to-end security management in MQTT can improve system scalability. • Security levels linked to topics allow a compromise between security and resources. • Dynamic security allows adapting to changing risks, preserving device resources. • Security hierarchy linked to topic/sub-topic allows different connections/clients establishment.

An emerging research trend on sixth generation systems is undoubtedly that linked to the development of Digital Twins of 6G networks. These network’s Twins can contribute to a smarter management of the physical network, which is increasingly oriented towards sustainability and guarantee of targets expressed in terms of KVIs (key value indicators) in addition to the traditional KPIs (key performance indicators). In this vein, this paper presents a reference architecture for a Digital Twin of a 6G system sensitive to sustainability issues and equipped with in-network computing capabilities. The main features and components are designed to be able to flexibly implement sustainable networking principles and respond to user intents based on sustainable KVIs. As a proof-of-concept, an example is shown of how the DT of a network can help implement and configure the offering of in-network AI services in a sustainable manner by making appropriate predictions of the evolution of the represented physical infrastructure.

The evolution of Next-Generation Networks is driven not only by technological advancements but also by the need to address broader social and environmental concerns. Indeed, in the transition to increasingly interconnected and digitalized societies, it becomes imperative to consider additional key values beyond mere technological performance. Sustainability, encompassing social, economic, and environmental dimensions, emerges as a crucial guiding principle shaping the development and deployment of future networks. This paper explores the evolving landscape of programmable networks, emphasizing the integration of sustainability principles to foster resilient, inclusive, and environmentally conscious network infrastructures. Sustainability principles are used to define Key Value Indicators (KVIs), which can be embedded into an Intent-Based Network to define the user and/or enterprise sustainable goals expressed in terms of intents. Two examples of KVIs are also discussed to analyze the process of reaching their definition.

An emerging modality, increasingly used by edge devices, to train machine learning models in a distributed and cooperative way is Federated Learning (FL). It combines an increase in the quality of the learning process with data privacy needs. Alongside the advantages of this emerging paradigm, however, there is a critical factor that risks seriously affecting its effectiveness in future 5G and 6G application scenarios: the possible delays deriving from the scarcity of communication resources to connect the clients to the server, which risks slowing down the process excessively and making it less effective in the presence of new types of real-time applications typical of 5G/6G scenarios. To face this issue, the paper proposes a new approach to client selection that, unlike the various approaches to streamlining FL communications proposed so far, starts from a typically networking research point of view and makes use of the potential of the Software-Defined Networking (SDN) paradigm for the choice and continuous dynamic update of the clients participating in the FL process. This allows to keep the distributed learning process at high levels of effectiveness and efficiency, i.e., guaranteeing an overall time reduction of the FL process under different network traffic load conditions, as demonstrated by the performance evaluation campaign conducted through the implementation of a testbed platform.

While the concept of AI4Net has been widely discussed in the past decade and adopted in 5G, its counterpart, Net4AI, has not gained that much attention so far. This is mostly due to the absence of solutions for the network to support AI applications beyond providing the communication infrastructure. In-Network Computing (INC) is a promising paradigm, potentially being integrated into 6G, which opens new solutions for realizing Net4AI. This paper focuses on the specific case of INC-assisted Split-AI. A Neural Network (NN) is split vertically and the executions of some layers of the split NN are offloaded to the entities of an Intelligent 6G User Plane. With the example of INC-assisted Split-AI, we elaborate on the challenges of Net4AI and discuss key requirements for the 6G architecture in terms of novel capabilities and information exchange.

The Adaptive Data Rate (ADR) method used in LoRa networks to manage data rate, airtime, fairness, and energy consumption has proven to be not so efficient in scenarios with heavy traffic load and high node density. This issue led to intense research efforts, aimed at creating more efficient algorithms, able to manage dynamically contentions and data transmissions. Specifically, the goal of this paper the proposal a strategy to assign communication parameters, such as Spreading Factors (SF) and channel frequencies, to competing nodes and at the same time balance the load on different channels by exploiting the new concept of Interference Region. The performance of the proposed mechanism is compared with three benchmarks, namely the classic ADR, and two previously proposed mechanisms called ALS-LB and EXPLoRa-AT, under homogeneous and heterogeneous traffic conditions.

Digital Twins (DTs), which are paired to Internet of Things (IoT) devices to represent them and augment their capabilities, are gaining ground as a promising technology to enable a wide variety of applications in the sixth-generation (6G) ecosystem, ranging from autonomous driving to extended reality and metaverse. In particular, “social” IoT (SIoT) devices, which are devices capable to establish social relationships with other devices, can be coupled with their virtual counterparts, i.e., social DTS (SDTs), to improve service discovery enabled by browsing the social network of friend devices. However, the mobility of SIoT devices (e.g., smartphones, wearables, vehicular on board units, etc.) may require frequent changes in the corresponding SDT placement in the edge domain to maintain a low latency between the physical device and its digital replica. Triggering SDT relocation at the right time is a critical task, because an incorrect choice could lead to either increased delays or a waste of network resources. This work proposes a learning-powered social-aware orchestration that predicts the mobility of SIoT devices to make more judicious migration decisions and efficiently move the paired SDTs accordingly, while ensuring the minimization of both intra-twin and inter-twin communication latencies. Different machine learning (ML) and deep learning (DL) algorithms are used for SIoT device mobility prediction and compared in terms of a wide set of meaningful metrics in order to identify the model that achieves the best trade-off between prediction accuracy and inference times under different scenarios. Simulation results showcase the improvements of the proposal in terms of reduced network overhead (by up to a factor of 3) and intra-twin and inter-twin communication latency (by up to 10%) compared to a more traditional solution, which activates the relocation of the DTs at fixed time intervals following periodic optimizations.

According to the 6G vision, the evolution of wireless communication systems will soon lead to the possibility of supporting Tbps communications, as well as satisfying, individually or jointly, a plethora of other very stringent quality requirements related to latency, bitrate, and reliability. The achievement of these goals will naturally raise many research issues within radio communications. In this context, a promising 6G wireless communications enabler is the reconfigurable intelligent surface (RIS) hardware architecture, which has already been recognized as a game-changing way to turn any naturally passive wireless communication setting into an active one. This paper investigates RIS-aided multicast 6G communications by first modeling the system delay as a first-come-first-served (FCFS) M/D/1 queue and analyzing the behavior under different blockage conditions. Then the study of multi-beam operation scenarios, covering multicast and RIS-aided multicast communications, is conducted by leveraging an M/D/c queue model. Achieved results show that large-size RISs outperform even slightly obstructed direct BS-to-user paths. In contrast, RISs of smaller sizes require the design of sophisticated power control and sharing mechanisms to achieve better performance.

Federated learning (FL) is gaining momentum as a prominent solution to perform training procedures without the need to move sensitive end-user data to a centralized third party server. In FL, models are locally trained at distributed end-devices, acting as clients, and only model updates are transferred from the clients to the aggregator, which is in charge of global model aggregation. Although FL can ensure better privacy preservation than centralized machine learning (ML), it exhibits still some concerns. First, clients need to be properly discovered and selected to ensure that highly accurate models are built. Second, huge models may still require to be exchanged from the aggregator to all the selected clients, incurring a not negligible network footprint. To tackle such issues, in this paper, we propose a framework built upon in-network caching, multicast and name based data delivery, natively provided by the Named Data Networking (NDN) paradigm, in order to support client discovery and aggregator-clients data exchange. Benefits of the proposal are showcased when compared to a conventional application-layer solution.

Internet of Space Things (IoST) is a challenging paradigm, which is currently attracting great interest from the scientific and industrial communities. IoST is based on the integration of the space segment into the global Internet-of-Things (IoT) infrastructure. In the relevant literature, reference is generally made to multiple constellations of nanosatellite platforms, used to enable IoT services on a global scale, including also disadvantaged and poorly infrastructured areas. In this article, we focus on multitenant IoT scenarios, wherein multiple CubeSats constellations are enabled to offer services by exploiting a dynamic federation model. The objective is to efficiently provide services in an IoST scenario by leveraging an effective cooperation strategy originally designed for terrestrial IoT networks, the Mobile-IoT-Federation-as-a-Service (MIFaaS) paradigm. We extend this vision to IoT satellite networks in order to allow a constellation of satellites to effectively execute tasks through a tight cooperative behavior with other CubeSats constellations. The reported performance evaluation studies show that better performance, in terms of percentage of tasks successfully completed, can be achieved through the implementation of the proposed cooperation paradigm.

As the fifth-generation (5G) and beyond (5G+/6G) networks move forward, and a wide variety of new advanced Internet of Things (IoT) applications are offered, effective methodologies for discovering time-relevant information, services, and resources are being demanded. To this end, computing-, storage-, and battery-constrained IoT devices are progressively augmented via digital twins (DTs) hosted on edge servers. According to recent research results, a further feature these devices may acquire is social behavior; this latter offers enormous possibilities for fast and trustworthy service discovery, although it requires new orchestration policies of DTs at the network edge. This work addresses the dynamic placement of DTs with social capabilities [social digital twins (SDTs)] at the edge, by providing an optimal solution under IoT device mobility and by accounting for edge network deployment specifics, types of devices, and their social peculiarities. The optimization problem is formulated as a particular case of the quadratic assignment problem (QAP); also, an approximation algorithm is proposed and two relaxation techniques are applied to reduce computation complexity. Results show that the proposed placement policy ensures a latency among SDTs up to 1.4 times lower than the one obtainable with a traditional proximity-based only placement while still guaranteeing appropriate proximity between physical devices and their virtual counterparts. Moreover, the proposed heuristic closely approximates the optimal solution while guaranteeing the lowest computational time.

The classic ADR method used by LoRa for optimizing data rates, airtime and energy consumption in the network has proven to be not very efficient in scenarios characterized by a high number of transmitting nodes. There is therefore a need to implement alternative mechanisms to reduce collisions and packet transmission delay in high dense IoT network scenario with increasing traffic load. The research presented in this paper contributes to satisfy this need by proposing a new mechanism aimed at traffic load balancing that leverages the switching of LoRa devices between Gateways in a multi-Gateway scenario. From the comparison with the classic ADR it clearly emerges how the proposed technique can obtain significantly better performance levels in terms of number of collisions, energy consumption and packet delay.

With more than 75 billions of objects connected by 2025, Internet of Things (IoT) is the catalyst for the digital revolution, contributing to the generation of big amounts of (transient) data, which calls into question the storage and processing performance of the conventional cloud. Moving storage resources at the edge can reduce the data retrieval latency and save core network resources, albeit the actual performance depends on the selected caching policy. Existing edge caching strategies mainly account for the content popularity as crucial decision metric and do not consider the transient feature of IoT data. In this article, we design a caching orchestration mechanism, deployed as a network application on top of a software-defined networking Controller in charge of the edge infrastructure, which accounts for the nodes’ storage capabilities, the network links’ available bandwidth, and the IoT data lifetime and popularity. The policy decideswhich IoT contentshave to be cached andin which nodeof a distributed edge deployment with limited storage resources, with the ultimate aim of minimizing the data retrieval latency. We formulate the optimal content placement through an Integer Linear Programming (ILP) problem and propose a heuristic algorithm to solve it. Results show that the proposal outperforms the considered benchmark solutions in terms of latency and cache hit probability, under all the considered simulation settings.

Non-Terrestrial Networks (NTNs) based on the emerging 5G New Radio (NR) technology stand as an effective solution to complement terrestrial networks in service provisioning, owing to their ability to satisfy requests of anywhere and anytime connection, and to increase network scalability by delivering multicast/broadcast services to groups of NTN terminals through Point-to-Multipoint transmissions. However, current satellite systems operating at different orbits remain isolated islands and fail to express their true potential if not properly made interoperable with ground networks. In the light of effectively integrating existing 5G networks into a unified system, we propose a cooperative radio resource management scheme that enhances the performance of an integrated terrestrial-NTN system based on the emerging 5G NR technology. It leverages the principles of multicast subgrouping techniques to determine which users will get connected to either terrestrial base station (i.e., gNB) or NTN cell (i.e., NTN-gNB) and properly allocate resources in order to improve the overall network throughput. Simulation results show the effectiveness of the proposed solution.

Software Defined Networking (SDN) and Named Data Networking (NDN) have been recently advocated as complementary paradigms to improve content distribution in the next-generation Internet. On the one hand, SDN offers a centralized control plane that can optimize routing decisions; on the other, the distinctive features at the NDN data plane, such as name-based delivery, in-network caching, and stateful forwarding, simplify data dissemination. In the integrated design, when a request cannot be handled locally at the NDN data plane in the Forwarding Information Base (FIB), the SDN Controller is contacted to inject the forwarding rule. Decisions such as which rules need to be stored in the node and for how long deeply affect the packet forwarding performance. This paper debates about the issues related to forwarding rules in the FIBs of SDN-controlled NDN nodes, by specifically accounting for their name-based nature, representing a key novelty compared to legacy SDN implementations. Quantitative results are reported to showcase the impact of crucial parameters, like the content popularity, the content requests rate, the table size, on the FIB performance in terms of valuable metrics (e.g., hit ratio, rejected requests, incurred signaling with the Controller).

The ever-increasing demand for high-quality video contents over mobile networks is pushing Telco operators towards the design of new delivery solutions. 3GPP has defined Multimedia Broadcast/Multicast Service Single Frequency Network (MBSFN) to enable the simultaneous transmission of the same content within multiple cells over the same radio resources, with improved network scalability and spectral efficiency. This paper proposes a Dynamic MBSFN Area Formation (DMAF) algorithm that suitably selects the adjacent synchronized cells to include in any MBSFN Area of a 5G New Radio (NR) system to the purpose of increasing the system Aggregate Data Rate while avoiding user outage. The proposed algorithm dynamically creates MBSFN Areas by leveraging the multicast “subgrouping” paradigm for Scalable Video Coding (SVC) traffic delivery. Cells are grouped into different MBSFN Areas and any cell can be part of Disjoint MBSFN Area or Overlapping MBSFN Area. Each Overlapping MBSFN Area broadcasts a Base video flow at a given quality level to all users, whereas Enhancement Layers are only delivered to users with better channel conditions. Simulation results testify to the better performance achieved by the proposed algorithm w.r.t. other schemes available from the literature.

Mobility as a Service (MaaS) implies the integration of different transport services in a unique platform accessible by commuters on demand. Collection and processing of data concerning the mobility of customers is crucial to calculate trips options satisfying users' needs and preferences. In this paper, we propose to exploit Multi-access Edge Computing (MEC) facilities to more efficiently deploy MaaS solutions. Specifically, we design a MEC-based MaaS framework that is fully compliant with the Open Mobile Alliance (OMA) Lightweight Machine-to-Machine (LwM2M) protocol. The OMA LwM2M server hosted in the MEC platform continuously collects data from the commuters, and uses native MEC applications to provide value-added services. The OBSERVE extension of the Constrained Application Protocol (CoAP) is used to reduce energy consumption during data collection from the OMA LwM2M clients installed in the mobile user devices. Preliminary results are collected that show the performance of the proposed MaaS framework, integrated with a mobility generator tool (i.e., SUMO) that emulates the commuter paths.

This talk addresses an issues, deeply felt in next generation networks, concerning the management of group communications in scenarios characterized by the massive presence of Internet of Things devices acting as “prosumers” (consumer&producer) of services based on the exchange of huge data amounts. This will put a strain on existing networking primitives and their efficient management will be possible only if new paradigms are made available. Starting from this assumption, the talk will discuss the possibility of leveraging Social Networking and Software Defined Networking technologies and concepts towards the definition of a novel network primitive for the Internet of Things. The new primitive, called Sociocast, has the potential to enable trusted group-oriented communications, in-network publish&subscribe mechanisms, dynamic and selective firewalling, flexible data casting. During the talk a distributed architectural solution is presented, some performance results shown, and open research issues discussed.

A new class of miniaturized satellites, named CubeSats, have recently drawn the attention of the academic community first, and later of industry too, because they appear as a high attractive solution to provide a true widespread connectivity that allows also objects in remote areas to be part of the global Internet of Things (IoT). In this paper, we study the integration of this kind of satellites into multi-tenant scenarios, wherein multiple CubeSats constellations may be able to offer services even in an integrated manner. In particular, an IoT platform running within SDN/NFV-ready infrastructures which also includes CubeSat segments is designed. In the proposed architecture, CubeSats are considered as IoT sensing and actuation devices in the sky always available and able to provide enhanced services through their virtual counterpart (i.e., the virtual object). Useful scenarios are described and studied in which different constellations of CubeSats can be orchestrated via the proposed virtualisation platform to cooperate in providing IoT services.

The Multi-access Edge Computing (MEC) paradigm and the Cellular Vehicle-to-Everything (C-V2X) technology prove to be good candidates to address the vehicular applications' demands of high-performing connectivity and low-latency access to computing and storage resources. MEC provides cloud-like resources at the network edge, i.e., at the Multi-access Edge (ME) host. While vehicles move around, a service application instance running on a ME host may be triggered to move to another ME host to better support the application's demands. As a side effect, this migration may undermine service continuity. In this paper, we refer to the latest available ETSI MEC and 3GPP C-V2X specifications to investigate the issue of service migration between ME hosts in the context of vehicular communication. Early experimental results provide measures of the service migration latencies when ME applications run as Docker containers.

In recent years identifier/locator splitting (ILS) has been proposed as a promising future Internet solution to the so-called “semantic overload of addresses” problem. It is currently under debate whether the ILS approach, which entails identifier-to-locator resolution procedures, could ensure scalability, session continuity, and mobility across heterogeneous multiaccess networks as demanded by Internet of Things (IoT). In this paper, it is proposed to exploit the Social IoT concept to address the above issues. More specifically, a scheme is introduced that browses the social graph of devices to find information about the locator of the intended destination. Results show that the proposed solution outperforms the alternative ILS approaches in terms of number of hops and latency incurred to accomplish the resolution procedure, at the cost of a slight increase in the storage demands to track social relationships.

Pushed by the challenging demands of fifth generation (5G) use cases and the recent advancements in virtualization technologies, edge network devices are rapidly evolving from simple forwarders to softwarized infrastructures augmented with computing and storage capabilities. Such a trend blurs the distinction between IT and telco domains and paves the way for the integrated management of network and computing resources. In this paper, we focus on the interplay of the Software Defined Networking (SDN) and Named Data Networking (NDN) paradigms as key drivers for the orchestration of computing services in softwarized edge infrastructures. We propose a new framework that brings out the best of the SDN centralized intelligence to take “smart” decisions and inject rules for service allocation (e.g., retrieve input data, execute a function over them), and the best of the adaptive NDN forwarding plane and its native in-network caching to request and deliver services by name. Within the framework, we devise a service allocation strategy that aims at selecting as an executor, among the potential candidates, the one which is able to guarantee the shortest service provisioning delay for each service request, while accounting for the network topology, the links status, and the available computing resources in the edge nodes. Performance evaluations testify to the superiority of our proposal against benchmarking solutions from the literature under different operation settings.

The ever-increasing demand for ubiquitous high- data rate services pushes the Telco operators to face high challenging requirements for supporting bandwidth-hungry applications and for ensuring service continuity when a user is moving over a wide area. To guarantee this, Mobile Satellite Services (MSSs), especially Multimedia Broadcast Multicast Services (MBMSs), have gained great importance. Therefore, in this paper we propose a novel Radio Resource Management scheme for the efficient allocation of radio resources when delivering multicast video flows in 5G Satellite systems. The proposed Satellite - Multicast Subgrouping Multiple Layers (S-MSML) scheme jointly exploits both the Multicast Subgrouping and the Scalable Video Coding (SVC) technique to provide a minimum required quality to all multicast users and enhanced video quality to users in good channel condition. Finally, the results show that the proposed algorithm achieves better performance than the Legacy approach when considering multiple multicast groups in all considered environments.

The Identifier/Locator Splitting (ILS) paradigm has been proposed in the future Internet research arena to address the semantic overload of IP addresses. In this paper the integration of the Social Internet of Things (SIoT) concept into ILS solutions is investigated. Indeed, SIoT has been recently argued as a promising approach to improve the performance of identifier-to-locator mapping procedures. More specifically, we describe the general approach, propose an architecture and show some preliminary performance results obtained through simulations. The proposed SIoT-enabled ILS architecture relies on distributed repositories of virtual counterparts of entities that store Friendship Tables specifically introduced to enable the mapping information to be retrieved by surfing the social graph. Achieved results in a smart campus scenario show that the proposed approach achieves better performance, in terms of number of hops, than a mapping solution based on Distributed Hash Tables (DHT).

Named Data Networking (NDN) has been recently extended to enable the discovery and provisioning by name of in-network cloud-like services such as processing and data storage. Such a feature is particularly helpful in distributed edge environments, where mobile end devices can be involved in service offering. In such a context, a challenging issue is to motivate a mobile device to behave as a provider and share its resources (e.g., CPU, memory) in order to assist other end devices (consumers), in wireless proximity, asking for a given service. In this paper, we propose a solution revolving around two concepts: enhanced NDN primitives and a social-driven stimulus for mobile devices to volunteer as service providers. A bio-inspired response function is used by a potential provider's device to rate both its available resources and the social ties with the current consumer's device, established according to the Social Internet of Things (SIoT) paradigm. An early evaluation showcases to which extent the conceived solution allows a consumer to find a nearby provider available to offer its services, under different social neighbourhood settings.

Device-to-Device (D2D) communication will be one of the key enabling technologies for the future fifth generation (5G) cellular systems. A D2D communication allows nearby devices to transmit data directly, without passing through the network. Thanks to the proximity between devices, it allows to boost network performance by improving data rate, energy saving, and delay. Objective of the proposal in this paper is to securing future D2D communications. To this purpose, a new mechanism is designed which leverages (i) social trustworthiness, achieved through the Social Internet of Things (SIoT) paradigm, and (ii) encryption based on the Diffie-Hellman Key Exchange (DHKE) protocol for public key distribution. Results of a simulation campaign carried out by using MATLAB demonstrate that the proposed protocol can effectively enhance the protection of transmitted data by excluding users considered to be unreliable on the basis of both their reputation and their past behavior.

Large-scale smart environments (LSEs) are open and dynamic systems typically extending over a wide area and including a huge number of interacting devices with a heterogeneous nature. Thus, during their deployment scalability and interoperability are key requirements to be definitely taken into account. To these, discovery and reputation assessment of services and objects have to be added, given that new devices and functionalities continuously join LSEs. In spite of the increasing interest in this topic, effective approaches to develop LSEs are still missing. This paper proposes an agent-based approach that leverages edge computing and Social Internet of Things paradigms in order to address the above mentioned issues. The effectiveness of such an approach is assessed through a sample case study involving a commercial road environment.

In this paper the MIFaaS (Mobile-IoT-Federation-as-a-Service) paradigm is proposed to support delay sensitive applications in the Internet of Things (IoT). This objective is reached by leveraging on the federation of distributed services and things at the infrastructure Edge and exploiting the real-world awareness and capabilities of IoT devices at the ground. MIFaaS enables value-added services by implementing the dynamic cooperation among private/public clouds of IoT objects with the purpose to enhance the efficiency in the provisioning of delay-constrained IoT services and increase the number of successfully delivered IoT services. The proposed paradigm is studied in a cellular environment based on standard Long Term Evolution (LTE). The simulative results we present demonstrate how the proposed federation solution of private/public IoT clouds outperforms alternative solutions with no federations and support of resources offered by the Cloud. Moreover, an analysis of the limitations and of the possible enhancements for cellular systems to support the proposed paradigm is drawn.

Edge Cloud infrastructure will play a key role in extending the range of supported real-time cloud applications, by guaranteeing extremely fast response times. However, user mobility requires fast relocation of service instances, which represents an open challenge for resource-constrained cloudlets interconnected by high-latency and low-bandwidth links. In this paper, we investigate container-based virtualization techniques to support dynamic Mobile Edge Computing (MEC) environments. In particular, we design a framework to guarantee fast response time, by proactively exploiting service replication. A preliminary performance analysis is conducted to identify the possible advantages introduced by the proposed approach compared to classic migration procedures.

In emerging fifth generation (5G) systems, mobile social networks are expected to play an important role to enable proximity-based content distribution among devices. In this paper, we address social-awareness aspects and device-to-device (D2D) communications for information diffusion solutions in emergency scenarios. Context-aware information is collected from a set of devices deployed in the environment and received data are integrated and elaborated at the cellular base station before being delivered. In such a framework, we model the expected information diffusion time by taking into account both networking- and sociality-related metrics. In particular, we introduce the so-called social intercontact time which is able to model the interaction frequency between the user and a generic social platform. The proposed approach is compared with alternative solutions where the dissemination process is either managed through direct links from the central base station, as a conventional multicast scheme, or with the support from proximity communications, as a D2D-enhanced multicast scheme. The results of a performance assessment study show that the proposed framework achieves considerable gains, up to 50%, in terms of overall information diffusion time and data rate per user equipment.

The constant and fast increase in the number of heterogeneous Internet of Things (IoT) devices that populate everyday life environments brings new challenges to the full exploitation of the computation, memory, sensing, and actuation resources associated to them. In this context, device virtualization solutions and platforms may definitely play a key role in enabling the desired tradeoff between flexibility and performance. This paper focuses on lightweight virtualization technologies for IoT devices, suitably thought to effectively deploy new integrated applications and to create a novel distributed and virtualized ecosystem. Two different frameworks for container-based IoT service provisioning are compared, the one based on a direct interaction between two cooperating devices and the other based on the presence of a manager supervising the operations between cooperating devices forming a cluster. In the latter case, accounting for the growing impetus to move intelligence toward the edge of the network, management features are implemented at the network access point to provide short latency responses. We also introduce the outcomes of a thorough performance evaluation campaign conducted via a real IoT testbed. The measurements, performed by accounting for the constraints of typical IoT nodes, shed light on the actual feasibility of container-based IoT frameworks.

Fifth generation (5G) systems are expected to introduce a revolution in the ICT domain with innovative networking features, such as device-to-device (D2D) communications. Accordingly, in-proximity devices directly communicate with each other, thus avoiding routing the data across the network infrastructure. This innovative technology is deemed to be also of high relevance to support effective heterogeneous objects interconnection within future IoT ecosystems. However, several open challenges shall be solved to achieve a seamless and reliable deployment of proximity-based communications. In this paper, we give a contribution to trust and security enhancements for opportunistic hop-by-hop forwarding schemes that rely on cellular D2D communications. To tackle the presence of malicious nodes in the network, reliability and reputation notions are introduced to model the level of trust among involved devices. To this aim, social-awareness of devices is accounted for, to better support D2D-based multihop content uploading. Our simulative results in small-scale IoT environments, demonstrate that data loss due to malicious nodes can be drastically reduced and gains in uploading time be reached with the proposed solution.

The widespread deployment of radio frequency identification (RFID) tags and readers paved the way for research activities focused on applications that go well beyond the mere identification of people and goods. In this context, the paper investigates an innovative paradigm, according to which the residual data storage capacity of passive RFID tags is used as a kind of “virtual” communication channel to exchange data in RFID ecosystems of the Internet of Things (IoT). The performance of the paradigm is assessed through the evaluation of a number of important communication parameters, such as goodput and delay. The analytical study, validated through simulations, evaluates the impact that the following key parameters have on the system performance: 1) radio channel errors; 2) collisions; 3) number of involved readers; 4) memory block reading size under noisy channel conditions; and 5) heterogeneous storage capacity of available tags. This allows obtaining design directives for a well-performing implementation of the proposed communication paradigm. In particular, accounting for the negative effects of channel errors on the system goodput, in this paper, we highlight the relationship between optimal memory reading block size and channel errors to maximize the communication performance.

This paper investigates relay-based schemes in cellular systems, where multihop device-to-device (D2D) communications are exploited for content uploading toward the eNodeB. All user equipments (UEs) are sources of their own content and form a multihop D2D chain, with the head of the chain being in charge of uploading all the generated content to the eNodeB. By pooling the cellular radio resources assigned to the D2D chain and by using high-quality short-range radio links, the proposed cooperative content uploading scheme guarantees lower upload delays than in the traditional cellular mode operation. To model the D2D chain formation in a cell and to best characterize self-interested users concerned about their own payoff, a constrained coalition formation game is defined, where each UE is a player whose cost is identified as the content upload time. The solution of the game determines the stable feasible partition for the UEs in the cell. We demonstrate through simulations that with this solution the content uploading time is reduced by 52% with respect to the traditional cellular mode.

Recently, mobile multimedia services have represented an increasingly large source of revenue for the telecommunication industry. Subscribers are often interested in simultaneously receiving the same data flow and, hence, they fuel the growing demand for multicast multimedia services. Therefore, the design of efficient radio resource management strategies to jointly handle multicast and more traditional unicast traffic and to increase user satisfaction is of primary importance for the successful deployment of future mobile networks. This paper proposes an efficient radio resource management framework to handle unicast and multicast multi-layer video services. The proposed virtual unified group (VUG) approach makes use of a channel-aware subgrouping principle to provide fair throughput to both unicast and multicast users. The idea is to assign unicast subscribers to a virtual group, thus allowing them to compete for network resources on an equal footing with multicast users. Simulations highlight the benefits that VUG provides in a long term evolution network scenario, under different traffic load conditions, in terms of throughput and fairness in the distribution of resources to unicast and multicast users.

Summary form only given. All market and technology studies forecast an explosive growth in the number of "things" that will be connected to the Internet. The resulting network is what is commonly known as the "Internet of Things" (IoT). When compared to the traditional Internet, the extremely high complexity of the IoT environments (usually characterized by a huge number of nodes, high heterogeneity of their resources and capabilities, uncertainty on their trustworthiness, etc.) poses new challenges that cannot be faced by even very smart objects singularly.Social behavior is the answer found by several creatures to face the complexity of the surrounding environment. Accordingly, the concept of Social Internet of Things (SIoT) has been recently introduced and is the subject of a rapidly increasing research effort.During the tutorial the introduction of social notions into the IoT will be motivated, the basic concepts of the SIoT paradigm explained, and the existing related research results and industrial experimentations surveyed. Besides, the architecture of a sample SIoT-based platform will be detailed together with some exemplary applications. Reference web site for this tutorial: http://www.social-iot.org.

The Information-Centric Networking (ICN) paradigm for the future Internet is fundamentally different from the classic host-centric Internet Protocol (IP). By leveraging unique, persistent and location-independent content names, ICN provides native multicast support, content-based security, in-network caching, and easy data access, which can be especially useful in the Internet of Things (IoT). In this paper, the attention is on the design of an ICN framework tailored to the smart home domain, considered as a major representative of IoT scenarios. The proposed solution encompasses the definition of a flexible and expressive naming scheme that supports data/command exchanges and configuration/ management operations, and also fits the common service models in the smart home domain (i.e., push, pull, multi-party). Use cases are provided to shed light on the system behaviour and preliminarily assess its potential and performance.

This paper addresses the radio resource management of multicast transmissions of video streaming services in the emerging 5G-Satellite systems. A subgroup-based approach is used to split any multicast group into subgroups. This allows an effective exploitation of multi-user diversity according to the experienced channel conditions and the achievement of a high throughput level. The main drawback is the high computational cost usually related to the selection of the optimal subgroup configuration. In this paper, we propose a low-complexity subgroup-based algorithm that achieves performance close to optimum. Our solution is suitable for implementation in practical systems, such as Satellite-Long Term Evolution (S-LTE), since the computational cost does not depend on the multicast group size and the number of available resources. Through simulations conducted in different radio propagation and multicast group environments, the effectiveness of our proposed scheme is assessed.

The huge number of nodes that is expected to join the Internet of Things in the short term will add major scalability issues to several procedures. A recent promising approach to these issues is based on social networking solutions to allow objects to autonomously establish social relationships. Every object in the resulting Social IoT (SIoT) exchanges data with its friend objects in a distributed manner to avoid the need for centralized solutions to implement major functionalities, such as: node discovery, information search and trustworthiness management. However, the number and types of established friendship affects network navigability. This paper addresses this issue proposing an efficient, distributed and dynamic strategy for the objects to select the right friends for the benefit of the overall network connectivity. The proposed friendship selection model relies on a Shapley-value based algorithm mapping the friendship selection process in the SIoT onto the coalition formation problem in a corresponding cooperative game. The obtained results show that the proposed solution is able to ensure global navigability, measured in terms of average path length among two nodes in the network, by means of a distributed and wise selection of the number of friend objects a node has to handle.

This paper investigates on novel effective schemes based on Device-to-Device (D2D) communications for data relaying, to upload content from a set of cooperating User Equipments (UEs) acting as sources of the data towards a cellular base station (eNodeB). Enabling factors of the resulting cooperative data uploading able to improve the system performance are: (i) the differentiated channel quality experienced by UEs and (ii) the introduced possibility to pool together the allocated radio resources. A constrained coalition formation game is used for multi-hop D2D overlapping coalition formation, where the time needed to upload the content is the utility for the players. The proposed model directly considers the coverage constraints for the D2D links among the players. The proposed solution allows to determine the final cooperating network topology as a tree of overlapping coalitions. We demonstrate that the solution guarantees an average gain in the uploading time for the UEs up to a 23% with respect to non-cooperative content uploading methods.

Dense Networks (DenseNet) and Multi-Radio Access Technologies (Multi-RATs) are considered as key features of the emerging fifth generation (5G) wireless systems. A Multi- RAT DenseNet is characterized by a very dense deployment of low- power base stations (BSs) and by a multi-tier architecture consisting of heterogeneous radio access technologies. In this work, we propose an effective RAT selection algorithm that efficiently manages the RAT handover procedure by (i) choosing the most suitable RAT that guarantees high system and user performance, and (ii) reducing unnecessary handover events. In particular, the decision to trigger a handover is based on a new system parameter named Reference Base Station Efficiency (RBSE). This parameter takes into account metrics related to both the system and the user: the BS transmitted power, the BS traffic load and the users' spectral efficiency. We compare, by simulation, the proposed scheme with the standardized 3GPP policies. Results show that the proposed RAT selection scheme significantly reduces the number of handovers and the end-to- end delay while maintaining high system throughput and user spectral efficiency.

The rapid demand growth for group-oriented services mandates telco operators to efficiently manage the contemporary presence of the unicast services and the emerging multicast applications. We propose a novel radio resource management approach for providing fair throughput to unicast and multicast users in a broadband wireless network. The idea is to assign unicast subscribers to a virtual group in order to compete on an equal footing with multicast users for network resource distribution. We also revisit the traditional fairness indexes in order to capture the fairness in the degree of user satisfaction for unicast and multicast users. Simulations highlight the effectiveness of the virtual group strategy in terms of achieved fairness in several scenarios and under different traffic loads.

The research on the Internet of Things (IoT) has made rapid strides towards the definition of a global network of interconnected objects. Some IETF Working Groups are giving major contributions in this direction by standardizing an IPv6-based framework for resource-constrained nodes. Although this solution handles different constrained networks' devices, it does not explicitly manage the integration with a key IoT enabler: the RFID (Radio Frequency Identification) technology. In this paper, we propose a CoAP-compliant solution where RFID tags are directly accessible via a reader that acts as a proxy. The RFID tags, behaving as virtual CoAP servers, are included in the IoT realm. Key design aspects are addressed such as tag addressing, service and resource discovery, and mapping of CoAP methods onto RFID commands. Finally, the performance of the proposed solution is evaluated in order to provide useful indications for future deployments.

The widespread deployment of RFID technology and EPCglobal compliant devices paved the way for research activities on unconventional uses of RFID, beyond the mere identification of people and goods. Focus of this paper is on a recent proposal of passive RFID tags exploitation, in particular their data storage capacity, as a new “virtual” communication channel to exchange data within piconets of RFID readers. Although earlier researches already demonstrated the great potential of this paradigm, still an analytical model for the channel performance evaluation is lacking. The model we propose in this paper, to evaluate goodput and delay over the RFID channel, considers aspects like collisions and tag memory management problems. The trustworthiness of the obtained analytical results is also validated through a simulative campaign. The study definitely helps in (i) defining data transfer rates as a function of number of readers and storage capacity of available tags, and (ii) finding the number of readers that can be served while satisfying goodput and traffic delay constraints.

Internet of Things (IoT) applications will be based on the interactions between smart objects. In many applications such interactions are possible (or meaningful) when objects are close to each others, i.e., there is a co-presence. Unfortunately, to date there are no data traces providing information about the copresence of smart objects. Indeed, several mobility traces reporting humans' movements are available, but none of them contains information about the interactions between their objects. Objective of the work reported in this paper is to fill this gap. To this purpose, we start from user mobility patterns available from several datasets. We associate to each user a set of objects, based on a survey we have carried out over around 450 users. Accordingly, we analyze the statistics about the co-presence of objects. We carry out our analysis by exploiting the tools developed for the analysis of complex networks. Our objective is to identify the objects which are likely to play a key role in the interactions between smart objects in the IoT.

Multicast services over Long Term Evolution (LTE) have recently attracted the interest of the research community. Particular attention has been put on handling fairness requirements of multicast users and experienced channel quality. Conventional Multicast Scheme (CMS), Opportunistic Multicast Scheme (OMS), and multicast subgroup formation are the principal policies adopted to address this research issue. Little attention has been given so far to multicarrier systems like LTE-Advanced although the need for solutions appropriate to this system is strongly felt. In this paper we design radio resource management policies for the efficient delivery of multicast services in multicarrier LTE-Advanced systems and show how the relation between fairness and system efficiency can be controlled. Concerning the system resource management, game theoretic bargaining solutions are considered to best model fairness and efficiency (expressed in terms of throughput).

Long Term Evolution (LTE) is considered the most promising cellular system able to support the growing demand of multicast services (e.g., IPTV, video streaming) over mobile terminals. The design of effective strategies for the management of these applications is still an open issue, especially in scenarios where several multicast streams are simultaneously transmitted in a cell. In this paper we propose different resource allocation policies for the delivery of multicast scalable video flows. Such policies efficiently exploit the multi-user diversity and the frequency selectivity in order to match the requirements of both users and providers. The performance of the proposed strategies is analyzed through simulations by evaluating different cell deployment and user load environments and by focusing on spectral efficiency, throughput, fairness, and amount of resources needed for multicast service delivery. The last parameter is important in practical scenarios where multicast services share the available resources with other flows, e.g., unicast services.

Long Term Evolution (LTE) is the emerging 4G wireless technology developed to provide high quality services in mobile environments. It is foreseen that multimedia services and mobile TV will assume an important role for the LTE proliferation in mobile market. However, several issues are still open and meaningful improvements have to be introduced for managing physical resources when group-oriented services should be supplied. To this end, we propose a Frequency Domain Packet Scheduling (FDPS) algorithm for efficient radio resource management of Multimedia Broadcast/Multicast Services (MBMS) in LTE networks. The proposed scheduler exploits an optimization process to organize multicast subscribers in subgroups according to channel quality feedbacks provided by users. Optimization is driven by the aim of minimizing the “user dissatisfaction” with a consequent improvement in the network capacity. The effectiveness of the proposed scheduling algorithm is evaluated through simulation; obtained results demonstrate significant improvement in the multicast traffic performance.

The effectiveness of a cooperation paradigm, simultaneously involving cellular and short-range technologies, has been assessed in different scenarios and for various applications. A sample application is a cooperative file download service whereby a group of users exploits a short-range link to share the costs of a cellular download. Usually, following the optimization of parameters (such as download time, monetary cost, energy consumption) different portions of data are assigned for download to the involved users; they will then cooperatively exchange the content. The differentiation in the task assignment among the terminals has a direct influence on the player payoff distribution, which raises fairness issues in real scenarios where players are rational. In the present work, game theoretic concepts for cooperative games without side payments are investigated and a bargaining problem is studied. Its use in a two-nodes Bluetooth-based cooperative scenario offers suitable solutions to the problem of utility distribution between the nodes.

The integration of social networking concepts into the Internet of Things (IoT) has led to the so called Social Internet of Things (SIoT) paradigm, according to which the objects are capable of establishing social relationships in an autonomous way with respect to their owners. The benefits are those of improving scalability in information/service discovery when the SIoT is made of huge numbers of heterogeneous nodes, similarly to what happens with social networks among humans. In this paper we focus on the problem of understanding how the information provided by the other members of the SIoT has to be processed so as to build a reliable system on the basis of the behavior of the objects. We define a subjective model for the management of trustworthiness which builds upon the solutions proposed for P2P networks. Each node computes the trustworthiness of its friends on the basis of its own experience and on the opinion of the common friends with the potential service providers. We employ a feedback system and we combine the credibility and centrality of the nodes to evaluate the trust level. Preliminary simulations show the benefits of the proposed model towards the isolation of almost any malicious node in the network.

This paper focuses on the design of radio resource management policies for efficient delivery of multicast services in Long Term Evolution (LTE) systems. In order to find alternative solutions to the Conventional Multicast Scheme (CMS), an effective framework is proposed that splits multicast destinations into different subgroups, depending on the User Equipments (UEs) channel quality, and applies a subgroup based Adaptive Modulation and Coding (AMC) scheme. This approach allows a more efficient spectrum exploitation. Game theoretic notions are used for the multicast subgroups formation and the resource allocation problems. The effectiveness of the proposed framework is evaluated and four different bargaining solutions are compared in terms of data rate, fairness, and subgroup configurations.

Wireless cooperation is emerging as a viable approach for next generation networks to offer important benefits in terms of content transfer delay, data rate, energy consumption, and cell capacity. One of the possible applications of a wireless user cooperation paradigm is represented by the provision of content sharing services. Data is seeded into a cooperative cluster through cellular links while short-range links are used to distribute data to all the interested nodes. Besides showing the beneficial effects of cooperation, this paper focuses on the best way to seed information into such a cluster of nodes and on a solution offering benefits in terms of either the time or the energy consumption for the service. Starting from static environments, the potentialities offered by an ad-hoc conceived Genetic Algorithm (GA) are shown. The analysis is then extended to the more realistic nomadic environments with low speed pedestrian mobility for the nodes.

In this paper, a delay tolerant approach for traffic management in LTE over satellite link is presented. Due to the long propagation delays and frequent disruptions, mobile satellite communications pose many challenges, especially to the transport layer when the TCP protocol is used. We design and evaluate the performance of a transport protocol solution based on the DTN architecture in the satellite-LTE system. Our proposal, named Tiny Bundle Layer, acts as an overlay on top of different versions of TCP in order to overcome the satellite link impairments.

This paper introduces a user cooperation technique thought to support content sharing services in wireless environments. WLAN inter-device data exchange is effectively exploited, combined with network coding techniques. Specifically, the content of interest is seeded into the WLAN user group through cellular-enabled devices, while short-range links are used to cooperatively distribute data to all the interested users. The focus is on scenarios where nodes in the same network area are not all interested in the same content, they rather form different cooperative groups. Beneficial effects of intra-group cooperation have already been demonstrated in the past; differently, this research focuses on inter-group cooperation. Objective of this paper is the investigation of any obtainable benefit (either in terms of energy consumption, service latency, or probability of successful service distribution) from such a cooperative attitude of different groups.

A promising paradigm, that answers crucial needs raised by emerging wireless applications, foresees the cooperation of multiple terminals over short-range wireless links while downloading multimedia contents over long-range cellular connections. Energy consumption reduction is just one of the potential benefits the cited communication paradigm might offer. Undoubtedly, the main issue raised by the new paradigm is to develop a model of cooperative behavior, which can best meet the expectations of all the cooperating entities. Unfortunately, classic minimization problem solutions are usually conflicting with the concept of fairness, as it is sensed by rational players. A joint use of classical optimization and game theory based approaches may contribute to overcome the highlighted dichotomy between user satisfaction and stable minimal energy cost allocations. This paper studies the interactions among users in the presence of a cooperative file-sharing service and seeks appropriate solutions to achieve the lowest energy consumption is possible while motivating users to cooperate.

Abstract Multicast service delivery can be easily guaranteed to users in disadvantaged areas by effectively integrating HAPs (High Altitude Platforms) into the terrestrial cellular system. HAPs are meant to be as unmanned aerial vehicles, airships or aircrafts, which remain relatively stationary in the stratosphere at short distance from Earth compared to satellites. In the scientific literature, there is evidence of the effectiveness of a UMTS (Universal Mobile Telecommunications Systems) system augmented by the presence of HAPs, which are equipped with UMTS payloads and play the role of additional base stations. This integrated terrestrial‐space platform intrinsically fits the exigencies of rural and emergency scenarios, which are characterized by network resource scarcity, due to either geographical reasons (such as in rural areas) or to temporary resource over‐utilization/reduction (due to emergency status). In this paper, the focus is on the delivery of Multimedia Broadcast/Multicast Services (MBMS) in the reference integrated architecture. Main objectives are designing resource allocation policies to manage multicast groups between space and terrestrial coverages, and analysing their feasibility and performances in terms of offered grade of service. Copyright © 2008 John Wiley & Sons, Ltd.

The provision of Quality of Service (QoS) is one of the primary requirements for IEEE 802.16/WiMAX to become a reference technology for multimedia service delivery. This paper reports on the design and analysis of some channel- aware scheduling algorithms for downlink traffic delivery in a fixed point-to-multipoint WiMAX network. In particular, compensation-based and greedy approaches are compared according to their ability to provide QoS and fairness to traffic flows when not working in ideal channel conditions. Simulations highlight that the greedy philosophy fails to provide service differentiation, especially when users perceive heterogeneous channel conditions.

Multimedia broadcast multicast services (MBMS), introduced by Third Generation Partnership Project (3GPP) in universal mobile telecommunications system (UMTS) release 6 specification, have the aim to support downlink streaming and game services to groups of users. MBMS can supply users with resources in two different modalities: point-to-point (PtP) and point-to-multipoint (PtM). The power consumed by the network is an important topic to discuss when considering the presence of MBMS services. The UMTS system is, in fact, interference- limited; thus, the power available to Node B is limited and it must be enough to serve any user under its coverage. Therefore, the choice of the most efficient transport channel in terms of power consumption is a key aspect for the MBMS, since a wrong transport channel selection for the transmission of the MBMS data could adversely affect the overall capacity of the system. In this paper we search for the most efficient transport channel to convey MBMS data, by comparing the performance of the high speed downlink shared channel (HS-DSCH), the dedicated channel (DCH), and the forward access channel (FACH), for given transmission power levels and cell coverage size.

Focus of the present paper is the integration between high altitude platforms (HAPs) and terrestrial UMTS system to support multimedia broadcast/multicast services. HAPs are characterised by a wide coverage area, which makes them a very attractive solution to support broadcast and multicast applications, while increasing both resource capacity and grade of services. In the depicted scenario, we propose to enhance the system efficiency by envisaging a novel radio resource management (RRM) protocol based on the evaluation of the power consumption relevant to users belonging to each multicast group. We demonstrate that the use of the proposed RRM policy, coupled to a wise selection of transport channels, leads to the effective management of multiple multicast groups.

WAVE (W band Analysis and VErification) is a project funded by the Italian Space Agency (ASI) with the aim to design and deploy different missions for scientific experimental use of the W band channel in satellite data communications. The second phase (A2) of the Project is currently in progress. This paper summarises the main scientific results early achieved in the WAVE A2 Project on the analysis assessment of W band GEO and LEO satellite missions.

Mobile devices provided with cellular and short-range radio network interface cards offer the user potentials for new communication paradigms based on a cooperative behavior. The idea is that devices in close proximity exchange, through available short-range links, complementary shares of information downloaded from the cellular connections. Results in the literature have proven equal benefits for all partners in terms of energy consumption, achieved data rate, and transfer time, under homogeneous conditions. Notwithstanding, there could be heterogeneous cooperative scenarios in which gains are not perceived, unless novel smart policies for the content splitting among cooperating entities are implemented. In this paper we design a novel cooperation strategy based on a multi-criteria optimization algorithm for the bargaining of the content fraction each cooperating unit shall download according to the predicted cellular throughput. It will be shown that it is able to always match the expectations of the cooperating partners.

This paper introduces a novel seamless handoff approach for DVB-H networks aimed at reducing the user terminal power consumption and at making the handoff algorithm be driven by the quality of the user received signal. This implies the substitution of standard RSSI-based procedures with a method based on the Modulation Error Rate (MER) monitoring. The additional use of an underlying cellular network, for DVB-H related data delivering, allows to achieve additional advantages: a superior power saving and a faster handoff execution. Obtained results suggest that the DVB-H handoff protocol design is an issue, which definitely deserves further investigation in the view of making DVB-H an effective solution for delivering broadcast content to mobile users.

The strong user need for receiving multimedia content while on the move opens up new challenges in future hybrid wireless communication scenarios. Delivering broadcast and multicast multimedia services through existing cellular networks is surely one of the toughest issues to investigate. The wide coverage area of High Altitude Platforms (HAPs) makes them a very attractive solution to deliver multicast/broadcast applications to a large number of sparse users. The authors examine the implications arising from the integration of UMTS and HAP systems to provide Multimedia Broadcast and Multicast Services (MBMS). In this reference scenario, two radio resource management policies are compared in terms of overall offered Grade of Service (GoS). By a thorough simulation investigation, the performance trade-off between a "User Number oriented" vs. a "User Distribution oriented" solution is evaluated. The different conditions under which one approach outperforms the other are investigated, and the degree of achieved performance augmentation is highlighted.

Key issues in the design of soft handoff policies for DVB-H systems are energy saving and constant monitoring of the received signal quality. With this idea in mind, a novel algorithm is proposed in this paper with the aim of reducing the frequency of handoff-related measurements in DVB-H systems, thus enabling manifest power saving in portable terminals than in the case of standard RSSI-based procedure. The objective is accomplished by making handoff algorithm be driven by the quality of the signal received by the user, constantly monitored through techniques of MER (Modulation Error Rate) measurement and estimation. The performing behavior of the proposed mechanism, assessed through a comprehensive evaluation campaign, allows us being confident that this is a direction to consider for future research activities in the field of effective DVB-H handoff protocols design.

In this paper we provide a general and repeatable experimental evaluation campaign of location algorithms based on RSSI measures for active RFID systems. We start from the well-known LANDMARC approach and conduct a thorough investigation aiming at evaluating its actual potentials and limitations under different environmental conditions. For the sake of completeness, we compare its behavior with the one of a further technique, named RSSI spatial interpolation (RSI), which is taken as a representative of a wider family of solutions which also LANDMARC belongs to. Experimental results show that by even introducing some modifications, still both algorithms get poor performance in indoor scenarios; location errors lower than 2m are only attainable in limited size outdoor environments in 90% of the experiments.

The IEEE 802.16 standard has been promoted by the WiMAX (Worldwide Interoperability for Microwave Access) forum as a leading wireless broadband access technology. The packet scheduling mechanism represents the core of WiMAX QoS architecture; however, each vendor needs to design its own algorithm to offer effective quality provisioning to the end user. This paper reports on the design and analysis of a channel-aware WF2Q+ based scheduling algorithm for downlink traffic delivery in a point-to-multipoint WiMAX network. A technique for compensation of channel errors is proposed to preserve QoS and fairness of the scheduling algorithm when working under non-ideal channel conditions. Simulation analysis confirms the effectiveness of the compensation mechanism under different channel conditions, network load, and traffic characteristics.

The focus of this paper is on the integration of High Altitude Platforms (HAPS) into a terrestrial UMTS system to effectively support MBMS applications. Its main objective is the efficient allocation of transmission resources to multicast traffic streams (by suitably selecting terrestrial and/or HAP channels) while still preserving the desired Grade of Service of background unicast traffic. Specifically, we compare two different approaches to the Radio Resource Management (RRM) in the depicted scenario: the first one takes into account the Number of users in each multicast group to drive the RRM policies; while the second one bases the RRM behavior on the Distribution of users belonging to each multicast group. By conducting a thorough investigation, the performance trade-off between "User Number oriented" vs. "User Distribution oriented" solutions is evaluated. The different conditions under which one approach outperforms the other are investigated and the degree of performance augmentation is always highlighted.

In this paper we present a novel multi-criteria network selection algorithm for always best connected service provisioning. It relies on a suitably defined cost function, which at the same time takes into account metrics reflecting both objective, i.e. network related, and subjective, i.e. user preference related, conditions. Point of strength of our proposal is the implementation of the selection algorithm at a middleware layer; this hiding both network cost computation and 4G scenario complexity from user and application layers. The good performance observed is mainly due to the possibility of associating a weight to each cost parameter that is dynamically adapted to user preferences and profile not only on a per-session basis but also within the same session

To provide QoS guarantees to a variety of traffic types is becoming a key feature for the success of wireless LANs. In this paper, we contribute to this issue by proposing a framework under which the nodes in an IEEE 802.11e ad hoc network may cooperate to provide the user with the desired QoS level

This paper contributes to the issue of QoS differentiation in wireless ad hoc networks. The focus is on the IEEE 802.11e MAC protocol that we propose to enhance by introducing a mechanism to "dynamically" assign priorities to traffic. Priorities are hop-by-hop assigned according to network resource availability and load in order to satisfy throughput requirements of each class of traffic

In wireless LANs, QoS provisioning and multimedia traffic support are critical elements for the successful deployment of such networks. In this paper, we propose a dynamic mechanism to adapt data rate and priority of multimedia wireless stations equipped with IEEE 802.11e network cards. We show how the introduced dynamicity is able to improve performance of the enhanced distributed channel access (EDCA) of IEEE 802.11e networks.

In this paper a novel concept of "situation and location" based quality of service (QoS) control for next generation hybrid wireless system is investigated. A brief overview of the evolutionary paths involving the QoS concept is given and the new vision of I-centric telecommunications scenario is addressed. In such a context, a definition of a situation and location aware mechanism for QoS management and resource allocation is proposed by approaching the issue at a middleware layer in such a way as to make the underlying heterogeneous system completely transparent to the mobile user roaming across its segments.

Multi-layered networks exploiting HAP and satellite segments are becoming a very attractive solution to deploy global telecommunication infrastructures. In fact, they can help in offering users ubiquitous access to multimedia information in an efficient and cost-effective way. In this paper a multi-layered infrastructure is presented aiming at efficiently allocating bandwidth among different user typologies. Two different scenarios are considered for DVB-RCS service delivery. A one-layer system, with the satellite coverage stratum only, and a two-layer one, with an integrated HAP-satellite coverage layer. A simulation campaign is conducted in order to assess the performance of both scenarios and to compare their performance. This study is, therefore, intended as a research contribution to the understanding of the actual usefulness of introducing a HAP stratum into terrestrial-satellite hybrid wireless systems

In the present paper a modular mechanism for QoS management over the return channel of DVB-RCS satellite platforms is proposed. Main aim of the study is to contribute to the standardization research efforts towards the definition of effective QoS management policies over DVB-RCS return channels. By exploiting the proposed solutions a DVB-RCS satellite system is able to keep the throughput always at high levels while satisfying each service class negotiated QoS. Resource wasting is reduced and the performance of low priority traffics is always guaranteed through a "wasted resource reuse" mechanism implemented into the terminal. Proposed solutions are tested within a realistic platform through appropriate simulation campaigns that confirm the expected good performance.

In this paper the authors' attention is on the specification of a middleware functionality for dynamic QoS control in multimedia cellular environments, such as UMTS. The functionality implements a soft QoS paradigm, at the same time optimising the perceptual QoS provided to the end user according to his/her needs. It will be shown that by exploiting suitable performance indexes and resource redistribution algorithms both an acceptable grade of service and a good degree of user satisfaction can be achieved, without an excessive increase in the network-signalling load.

This paper aims at contributing to the dimensioning of the signalling bandwidth of a broadband geo-satellite system for multimedia communications. Signalling channels are used by the satellite terminals to set up connections and ask for on-demand resource assignment. A smart dimensioning of the satellite bandwidth plays a key role in the fulfillment of the service quality required by multimedia traffic and the effective exploitation of the satellite spectrum. We accomplish this task by designing a statistical centralised CAC accorded with an intelligent scheduling of the resource requests on board the satellite. The proposed traffic and resource management techniques have been tested over a simulation platform for the EuroSkyWay satellite system.

In this paper we propose and compare different techniques used by the satellite user terminals to randomly access signaling channels used for connection set-up. The reference scenario is represented by EuroSkyWay [G. Losquadro, 1996], a multimedia geostationary satellite platform conceived for providing personal communications.

This paper proposes a heuristic for re-computing the forwarding zone of route request packets for the location-aided routing (LAR) protocol in ad hoc wireless networks. We evaluate the influence of a "multi-step" resizing of the request zone on the LAR protocol performance, and make comparisons with other routing protocols (LAR scheme 1, LAR scheme 2, and promiscuous-dynamic source routing). Simulation results show that an accurate choice of the request zone size and of the number of steps for the resizing is successful in reducing the control overhead and increasing the throughput.

A large amount of research is currently focusing on the issue of the adaptive control of the quality-of-service (QoS) provided to multimedia applications in heterogeneous wireless systems. In this paper, the authors aim at contributing to this issue by proposing a mechanism that exploits user profiling techniques and suitable QoS mapping functions to introduce the soft QoS idea into a wireless multimedia scenario. The research objective is a QoS control architecture, which enables the continuous convergence between the actual user preferences and expectations and the resource constraints of the underlying wireless system. The proposed architecture operates between the system and the application layer. This allows it to achieve the intended results, by means of an effective dynamic reconfiguration of the applications and the contemporary renegotiation of the wireless resources.

This paper presents the analysis of some MAC protocols for multimedia applications in wireless ATM networks. The novelty of the approach is the delivery of multimedia applications over separate bearers over the radio interface while maintaining the original synchronisation degree. The presented techniques are able to guarantee low jitter, high degree of synchronization among different streams of the same user application, as well as to effectively exploit the limited radio spectrum of a wireless air interface.

Many recent researches have been conducted on the topic of multimedia applications management in integrated terrestrial-satellite systems with W-CDMA air interfaces. Among the many research issues, the design of suitable radio resource management techniques for soft-QoS guarantees to the user applications surely deserves a particular attention. This paper tries to contribute to this issue by reporting the lessons learned during a performance assessment study on a multi-tier UMTS system simulation platform. It shows that the achievement of good performance is strongly related to the right choice of call management algorithms, which take into account both the nature of the delivered traffic at each coverage level and the effects of the presence of the soft-handoff.

This paper proposes and analyses an architecture providing IP quality of service in integrated terrestrial-satellite networks. The IP Integrated Services framework is used to reserve resources on the satellite path and is combined with Differentiated Services in the terrestrial core network. A seamless integration is achieved by means of a gateway station that acts as interworking unit between terrestrial and satellite segments. The main focus is on the best mapping of integrated service traffic classes over satellite bearer connections.

This paper analyses the performances of two types of CAC algorithms proposed for deciding the admission of new connections in a geostationary satellite system. Both algorithms are specifically designed for high latency networks as they are characterized by low processing time on board, simple parameters, and real-time decisions. Tests are performed on the multimedia satellite platform of EuroSkyWay and aim at assessing the robustness of the CAC algorithms in guaranteeing the target quality to heterogeneous applications and in exploiting effectively the satellite bandwidth.

A new scheme for the management of real-time traffic over high-latency broadband satellite networks is described. Early studies on this topic have been reported by Iera, Molinaro and Marano (see IEEE J. Select Areas Commun.,, vol.18, p.2393-2403, 2000), with reference to an integrated terrestrial-satellite platform. In this paper, further enhancement is introduced into the traffic management scheme with a view to both the reduction of intrinsic impairments caused by the adverse operational environment and the achievement of better performance levels and QoS guarantees. A real-time traffic handling strategy, including distributed connection admission control (CAC) and traffic resource management (TRM) schemes, is harmonized with an in-band signaling technique for burst-based bandwidth request and with an effective policy for the allocation of radio resources. Furthermore, the impact of traffic reshaping at the satellite terminal on the CAC-TRM technique is tested. Added features reduce the adverse effects of the long propagation delay across the satellite link and show outstanding effectiveness in improving CAC-TRM performance and network resource efficiency, while matching service quality requirements. The main reason for the improved performance of the overall management scheme is the adaptability to different traffic profiles conveyed over satellite links.

An attractive challenge in the global communications scenario is the effective transmission of real-time bursty traffic over integrated terrestrial-satellite links. In this paper, the study focuses on the cited issue. In early studies we proposed a solution based on a connection admission control (CAC) scheme, coupled with a traffic resource management (TRM) functionality onboard. In the present work, the traffic handling strategy is complemented with a re-shaping module in the satellite terminal. The additional functionality shows outstanding effectiveness in improving CAC-TRM performance, especially when the long propagation delay across the satellite link prevents the CAC itself to guarantee the target QoS to certain types of traffic. By adopting an "intelligent" shaping at the satellite terminal the full effectiveness in managing system resources and in guaranteeing QoS is recovered, under a wide range of loading conditions and offered traffic profiles. The resulting policy is adaptable, in the sense that it can be dynamically adapted to the traffic profile.

This paper focuses on the analysis of two classes of TDMA-based MAC algorithms for wireless-ATM networks: the urgency-based class, scheduling the bandwidth requests on the basis of their urgency, and the buffer-based class, relying on the estimation of the queue length in the mobile terminals. The main features of the proposed urgency-based algorithms are: contention-based DAMA access, dynamic adaptation of reservation bandwidth, use of piggybacking and control mini-slots to handle real-time VBR traffic, and a scheduling mechanism based on the expiry time of the buffered cells. These aspects contribute to the better performance of urgency-based algorithms in handling heterogeneous traffic when compared to the buffer-based ones.

This paper describes a multiple access protocol, which answers the need for an efficient handling of the traffic coming from a wide range of broadband applications over geo-synchronous satellite air-interfaces. We propose a hybrid medium access control scheme, which combines both random access and demand assignment multiple access policies. It is coupled with a connection admission control algorithm, exploiting the advantages of statistical multiplexing. Dynamic management of the frame header allows minimizing the signaling overhead and maximizing the effectiveness of the reservation procedure.

In this paper we propose the use of an in-band signalling technique coupled with a distributed connection admission control and traffic resource management scheme, to combat the effects of high-latency in geostationary satellite systems. In-band request signalling is introduced to manage burst-based bandwidth demand from satellite terminals transmitting real-time variable bit rate traffic. Performance evaluation has shown the effectiveness of this technique in guaranteeing the service quality negotiated at connection set-up between the user and the network.

In this paper, a novel strategy for handling ATM connections of different natures, traffic profile, and QoS requirements in enhanced satellite systems is proposed. The conducted research starts from early studies on resource management in integrated terrestrial-satellite environments and focuses on a combined connection admission control/traffic resource management strategy for QoS provisioning to both real-time and non-real-time constant and variable bit rate sources. The resulting connection handling policy is dynamic, and effectively exploits the system bandwidth through the statistical multiplexing of traffic sources and a preemptive policy over the satellite air interface. The proposed strategy is suited for a generic integrated ATM-satellite system, although its effectiveness has been assessed on a multimedia satellite platform, based on the Ka-band payload and on-board processing.

Multi-tier cellular systems can answer the rising need for high transmission capacity and provide solutions for supporting heterogeneous (narrow-band and broad-band) traffic. The system analysed in this paper consists of a GEO satellite spot covering micro and macro-cellular layers to provide global user reachability and additional bandwidth. Enhanced traffic and resource management algorithms are proposed to effectively exploit the potential advantages of the multi-tier solution. The basic feature is the allocation of each connection to the most convenient hierarchical layer, according to the user mobility profile (fast/slow) and traffic nature. The system is loaded by heterogeneous traffic sources with different requirements in terms of bandwidth on the two radio link directions (symmetric and asymmetric data), delivery requirements and integrity needs. Algorithms are compared under different external conditions and their performance is assessed in terms of new call blocking and handoff dropping probabilities.

In this paper new techniques are proposed for the handling of multimedia traffic in a hierarchical multi-tier system involving microcellular, macrocellular and satellite coverage. In this environment, efficient channel assignment and hand-off management techniques become critical issues to fully exploit the benefits of the multi-layered architecture. The traffic flow control between layers has to maximise the system capacity without degrading the traffic QoS. This task is particularly hard when in the presence of multimedia calls, which ask for large amount of bandwidth and are characterised by the combination of traffic of different nature. The proposed algorithms differ from the traditional ones as they adopt a multi-bearer transport approach to carry multimedia traffic over the air-interface, coupled with suitable strategies for the allocation of each traffic component at the best layer. This leads to better resource utilisation and multimedia QoS guarantees, while minimising new call blocking and hand-off failure probabilities.

The work presented in this paper aims at contributing to the design of traffic and resource management techniques suited for integrated ATM-satellite systems with composite traffic load. The proposed techniques exploit sources statistical multiplexing and pre-emption based dynamic resource assignment. The features making the techniques suitable for ATM-satellite environments are: very low on-board processing, easy algorithm tuneability, statistical multiplexing of VBR sources, good exploitation of satellite bandwidth, and QoS provisioning to real-time and non-real-time traffic sources. The effectiveness of the proposed strategies is assessed on the Euro-SkyWay multimedia satellite platform.

User speed estimation can be exploited to improve the teletraffic performance in a mobile radio environment with multi-tier coverage. Many algorithms exploit the dwell time estimation to classify the users' speed and assign them to the right hierarchical layer. Most of them assume a constant user speed for the entire call. Thus, they loose their effectiveness in environments in which the mobile speed changes during the call. A new effective scheme for channel allocation and handoff management, based on the concept of bonus time, is proposed in this paper. Sophisticated simulative tools showed that the new scheme performs better, compared to the traditional ones, under a wide range of load distributions and vehicle traffic conditions both in urban and sub-urban environments.

To accomplish the task of providing a wireless access to the fixed network in a UMTS scenario, DECT is also expected to support multimedia traffic requiring multi-slot allocation. To this aim, a modified channel access algorithm, based on a slot-segmentation technique is adopted and combined with a priority-based management of the access requests. This paper illustrates the interesting effects of these enhancements in traditional DECT. The results of a performance evaluation activity in a multi-cell environment with wide-band and narrow-band traffic is reported. Achieved improvements are manifest in terms of both throughput and guaranteed QoS to each type of traffic.

In microcellular systems, cell overlapping can be effectively adopted to improve the teletraffic performance of the mobile terminal population. Anyway, the greatest advantages are mainly achievable by those users, located within an overlapping region, which can exploit the opportunity of receiving acceptable radio signals from more base stations. Effective resource assignment policies are thus necessary to make users located far from overlapping regions benefit from this feature as well. To this aim, a dynamic channel allocation scheme, based on the concepts of reserve channels and protection threshold, is proposed in this paper. A detailed description is given and, by means of analytical tools, it is shown that better performance compared to traditional schemes are attainable under a wide range of load distribution.

It is not an easy task in the UMTS environment to effectively design the transport and the management of traffic belonging to multimedia teleservices, due to the difficult communication requirements of such applications. It is proposed to contemporary use at the "transport" layer of the system several bearers, one for each traffic component of the multimedia service. Furthermore, a two-level (static and dynamic) priority mechanism is to be adopted by the higher protocol levels of the UMTS for the adaptation of call set-up, channel access, and admission control procedures to the nature of the multimedia services and to optimise the sharing of radio channel resources and the management of the reservation buffer. The results achieved demonstrate that the proposed mechanism shows a good performance especially during periods in which the system traffic load is high and reacts well to the worsening of the multimedia service quality, both in terms of information loss and synchronisation of its traffic components.

Wireless-PCS systems, through the introduction of new conception control functions, aim to respond to the user expectation of high performing services and the need for flexibility in the management of disparate categories of multimedia and multi-requirement applications supported by the networks. This paper contributes to the ongoing research work in this scenario by describing some proposals for the handling of multimedia teleservices both at the transport and control level, across the wired and wireless sides of an ATM-based wireless PCS system. Admission control on both sides, mobility management in the fixed side and resource allocation renegotiation are topics on which the study focuses.

The optimality of a dynamic adaptive bandwidth allocation mechanism on the inter-FDDI virtual circuits is analyzed. The proposed algorithm is based on the monitoring of InterWorking Unit buffer status and the request of quanta of bandwidth as the buffer content exceeds given thresholds. By using the analytical model proposed, the analysis of N-level bandwidth quantization algorithm performance can be carried out. The results, validated by simulation, allow comparison between three-level and two-level algorithms. The three-level algorithm shows a better response to statistical fluctuations of input traffic, while offering a better grade of service.>