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    Franco Davoli

    The chapter highlights techniques to simulate the behavior of real-time and non real-time satellite systems and clarifies possible application fields and motivations. Communication systems and, in particular, satellite components have... more
    The chapter highlights techniques to simulate the behavior of real-time and non real-time satellite systems and clarifies possible application fields and motivations. Communication systems and, in particular, satellite components have increased their complexity. Simulation is a reality to explore new solutions without increasing hazards and costs: long phases of space missions are completely dedicated to forecast the behavior of the systems to be implemented and simulations are widely used. The chapter focuses on methods to evaluate the efficiency of a simulator, underlines some traffic models suited to simulate communication systems and explains particular topics where the authors have direct experience. A couple of tools are presented applied to the satellite environment: a C-language based non-real­ time software simulator and a real-time simulator (emulator), where real machines can be attached to the tool, so as to avoid traffic modeling. Performance results are reported to better explain the concepts of the chapter.
    Power management and load balancing in data centers are becoming critical with the growing size of the infrastructure. In front of an increasing number of cloud networks, virtual machines (VMs) and containers, smart management and control... more
    Power management and load balancing in data centers are becoming critical with the growing size of the infrastructure. In front of an increasing number of cloud networks, virtual machines (VMs) and containers, smart management and control decisions are required, in order to instantiate or mobilize these virtual components. As regards reducing power consumption, it is also essential to consolidate virtual resources on the minimum possible number of servers compatible with performance requirements. In such a dynamic scenario, estimating the power that can be ascribed to a specific virtual component and its relation with the offered workload could be beneficial for optimized resource scheduling. Predicting the power consumption caused by a specific virtual component is however challenging. In this paper, two power models that relate a VM workload with the fraction of power consumed attributable to the VM are developed based on power profiling of a server. The accuracy of the proposed models is improved approximately by 3% compared to other existing models.
    Factory automation in the context of Industry 4.0/5.0 requires safety levels to satisfy more stringent and tight limits than those available so far. This goal is further challenged by the extension to the wireless environment of... more
    Factory automation in the context of Industry 4.0/5.0 requires safety levels to satisfy more stringent and tight limits than those available so far. This goal is further challenged by the extension to the wireless environment of industrial shop floor communications that were traditionally based on cabled networks. Starting with wireless LANs, the trend towards the use of industrial wireless is fostered by the advent of fifth Generation (5G) private connectivity and is bound to increase its pace in the evolution towards 6G. In particular, the interaction of human operators with industrial robots and autonomous vehicles on the shop floor is posing stringent safety requirements that in turn push forward the dependability and reliability limits of wireless connectivity. To help achieve these limits, this paper proposes a dynamic redundancy mechanism based on the real-time activation/deactivation of radio bearers instantiated between mobile devices carried by humans and machines and mult...
    Wireless private networks based on 5G (and beyond) connectivity represent a flexible high capacity solution for future smart industrial environments. In this context, the presence of both humans and robots introduces extremely high... more
    Wireless private networks based on 5G (and beyond) connectivity represent a flexible high capacity solution for future smart industrial environments. In this context, the presence of both humans and robots introduces extremely high reliability requirements in network control and management, for safety reasons. In this paper, a novel technique is described, based on real-time, dynamic management of radio bearer redundancy according to reciprocal human-robot positions, that is shown to improve network availability and reliability with the purpose of safe mobility in the industrial environment. Results obtained by simulation show that the current number of radio bearers supported by 5G radio systems may not be sufficient to meet stringent reliability requirements of critical applications.
    With the continuous improvements in communication technologies, users are demanding services with even higher and higher performance. High Key Performance Indicators (KPIs) have been set for this purpose in defining the next upcoming... more
    With the continuous improvements in communication technologies, users are demanding services with even higher and higher performance. High Key Performance Indicators (KPIs) have been set for this purpose in defining the next upcoming generation of mobile communications (5G). New emerging use cases and applications are enriching the already vast plethora of services that users can exploit through the Internet. However, traditional terrestrial networks have some intrinsic limitations that cannot be overcome with technology enhancements. For example, the terrestrial infrastructure will never be able to reach certain areas due to physical constraints, such as oceans, or the lack of a proper economic advantage, such as under-populated rural and remote areas.Satellite networks are foreseen to help the terrestrial infrastructure in several ways, especially in boosting enhanced Mobile Broadband (eMBB) services in converged 5G-satellite systems. New frequency bands have to be considered in order to guarantee the high required data rates. However, additional aspects should also be considered in order to deal with some impairments, such as the severe weather impairments that satellites need to tackle at high frequencies (Q/V bands).This paper proposes a novel smart gateway diversity strategy and validates its design through simulation campaigns, whose preliminary results show important performance gains with respect to other solutions available from the existing state-of- the-art.
    Abstract The fifth generation (5G) of mobile networks is seen as a key enabler to support the introduction of digital technologies in multiple sectors, empowering different verticals and enabling new business models. Thanks to native... more
    Abstract The fifth generation (5G) of mobile networks is seen as a key enabler to support the introduction of digital technologies in multiple sectors, empowering different verticals and enabling new business models. Thanks to native capabilities of 5G networks, especially network slicing, edge computing and multi-tenancy, highly integrated telecom infrastructures with end-to-end flexibility will be realized to lower the barriers for creating 5G-ready applications that are able to satisfy business and user necessities. In this context, the MATILDA Project has established a holistic framework that unifies the development, deployment and operation for this new kind of applications. Since Edge Computing is not natively supported by 4G, in order to anticipate the technological improvements foreseen with the advent of 5G, as well as to smoothen the transition to the new technology, this paper describes the design of the end-point between the mobile and edge environments that has been integrated in the MATILDA telecom layer platform. Such end-point, designed in a Virtual Network Function (VNF), allows intercepting and forwarding data and control traffic towards external Data Networks. Instances of this VNF can be horizontally scaled according to a decision policy, which determines the minimum number of instances required for the current load. Results show that the latency ascribable to the VNF processing is sufficiently low to satisfy the delay budget for all 5G use-cases up to 10 ms and that a QCI-based decision policy allows scaling with the traffic load, while still fulfilling the performance requirements of each application.
    The design of High Throughput Satellite (HTS) systems builds on the concept of Smart Gateway Diversity (SGD) to exploit the spatial diversity of gateways in case of feeder link outage, occurring because of atmospheric impairments... more
    The design of High Throughput Satellite (HTS) systems builds on the concept of Smart Gateway Diversity (SGD) to exploit the spatial diversity of gateways in case of feeder link outage, occurring because of atmospheric impairments introduced in Extremely High Frequency (EHF) frequency bands. The gateway handover procedure requires precise prediction algorithms and coordination among different network elements. This paper presents novel outage prediction algorithms based on machine learning concepts, integrated in the framework of SDN architectures, to efficiently orchestrate the gateway handover operations. Simulation campaigns prove the validity of the proposed concept and shed light on the potentials of the SDN architecture in future HTS systems.
    Overcoming the typical ossification of the traditional TCP/IP-based Internet infrastructure will allow opening the way for more flexible and energy efficient paradigms, able to provide a sustainable support to the constantly increasing... more
    Overcoming the typical ossification of the traditional TCP/IP-based Internet infrastructure will allow opening the way for more flexible and energy efficient paradigms, able to provide a sustainable support to the constantly increasing number of devices and services. To this goal, the INPUT Project will overcome current limitations by introducing computing and storage capabilities to edge network devices in order to allow users/telecom operators to create/manage private clouds "in the network". In addition, these new capabilities will allow replacing smart devices, such as network-attached storage servers, set-top-boxes, video sensors etc. with their virtual images. Although this virtualization process can clearly bring to a reduction of the emissions, along with the lowering of capital (CAPEX) and operational (OPEX) expenditures, on the other hand it requires more computational capacity at server level, which may erase the savings produced by virtualization in the absence of a thorough management and planning. In this respect, this paper presents a mathematical model that analyzes the impact of different levels of virtualization on the overall energy efficiency by thoroughly outlining how the carbon footprint varies depending on the virtualization level of a device.
    This article is a graphical, analytical survey of the literature, over the period 2010–2020, on the measurement of power consumption and relevant power models of virtual entities as they apply to the telco cloud. We present a novel review... more
    This article is a graphical, analytical survey of the literature, over the period 2010–2020, on the measurement of power consumption and relevant power models of virtual entities as they apply to the telco cloud. We present a novel review method, that summarizes the dynamics as well as the results of the research. Our method lends insight into trends, research gaps, fallacies and pitfalls. Notably, we identify limitations of the widely used linear models and the progression towards Artificial Intelligence/Machine Learning techniques as a means of dealing with the seven major dimensions of variability: workload type; computer virtualization agents; system architecture and resources; concurrent, co-hosted virtualized entities; approaches towards the attribution of power consumption to virtual entities; frequency; and temperature.
    5G networks evolution is tightly bounded with the need to support vertical industries network performance and operating requirements. Such an objective is associated with a set of challenges related mainly to the provision of frameworks... more
    5G networks evolution is tightly bounded with the need to support vertical industries network performance and operating requirements. Such an objective is associated with a set of challenges related mainly to the provision of frameworks that<br> can tackle aspects related to the various 5G stakeholders (e.g. software developers, application/service providers, telecom/infrastructure providers), without imposing strict requirements on their collaboration terms. Towards this<br> direction, in the current manuscript, we detail a novel holistic framework tackling the overall lifecycle of 5G-ready applications design, development, deployment and orchestration over application-aware network slices. Separation of concerns among the related takeholders per layer of the proposed architecture regards one of the basic considered principles.
    Within a 5G mobile network scenario, this paper adopts Multi-access Edge Computing (MEC) and Network Function Virtualization (NFV) technological frameworks to evaluate the gain in terms of user Quality of Experience (QoE) that can be... more
    Within a 5G mobile network scenario, this paper adopts Multi-access Edge Computing (MEC) and Network Function Virtualization (NFV) technological frameworks to evaluate the gain in terms of user Quality of Experience (QoE) that can be achieved when contents and server of a video delivery service move from the cloud at the edge of the Radio Access Network. The application scenario we set up envisions a video streaming service geared a small group of individuals who have strong social ties and who move in an urban space. The scaling up of this emergent type of social interaction is set to become in the near future highly demanding for the resources of mobile operators. The paper recreates the network infrastructure of a mobile operator in the city of Milano. We model network conditions through Mininet, and manage (computing, network and storage) resources by means of an orchestrator named OpenVolcano. The paper shows that, compared to the traditional cloud approach, a MEC one provides better QoE to group members simply taking advantage both of the proximity and distribution of mini data centers and of proper resource orchestration.
    This article surveys the literature, over the period 2010-2020, on measurement of power consumption and relevant power models of virtual entities as they apply to the telco cloud. Hardware power meters are incapable of measuring power... more
    This article surveys the literature, over the period 2010-2020, on measurement of power consumption and relevant power models of virtual entities as they apply to the telco cloud. Hardware power meters are incapable of measuring power consumption of individual virtual entities co-hosted on a physical machine. Thus, software power meters are inevitable, yet their development is difficult. Indeed, there is no direct approach to measurement and, therefore, modeling through proxies of power consumption must be used. In this survey, we present trends, fallacies and pitfalls. Notably, we identify limitations of the widely-used linear models and the progression towards Artificial Intelligence / Machine Learning techniques as a means of dealing with the seven major dimensions of variability: workload type; computer virtualization agents; system architecture and resources; concurrent, co-hosted virtualized entities; approaches towards attribution of power consumption to virtual entities; fre...
    SummaryThe space environment is still challenging but is becoming more and more attractive for an increasing number of entities. In the second half of the 20th century, a huge amount of funds was required to build satellites and gain... more
    SummaryThe space environment is still challenging but is becoming more and more attractive for an increasing number of entities. In the second half of the 20th century, a huge amount of funds was required to build satellites and gain access to space. Nowadays, it is no longer so. The advancement of technologies allows producing very small hardware components able to survive the strict conditions of the outer space. Consequently, small satellites can be designed for a wide set of missions keeping low design times, production costs, and deployment costs. One widely used type of small satellite is the CubeSat, whose different aspects are surveyed in the following: mission goals, hardware subsystems and components, possible network topologies, channel models, and suitable communication protocols. We also show some future challenges related to the employment of CubeSat networks.
    Network Functions Virtualization (NFV) is a network architecture concept where network functionality is virtualized and separated into multiple building blocks that may connect or be chained together to implement the required services.... more
    Network Functions Virtualization (NFV) is a network architecture concept where network functionality is virtualized and separated into multiple building blocks that may connect or be chained together to implement the required services. The main advantages consist of an increase in network flexibility and scalability. Indeed, each part of the service chain can be allocated and reallocated at runtime depending on demand. In this paper, we present and evaluate an energy-aware Game-Theory-based solution for resource allocation of Virtualized Network Functions (VNFs) within NFV environments. We consider each VNF as a player of the problem that competes for the physical network node capacity pool, seeking the minimization of individual cost functions. The physical network nodes dynamically adjust their processing capacity according to the incoming workload, by means of an Adaptive Rate (AR) strategy that aims at minimizing the product of energy consumption and processing delay. On the bas...
    An implementational model for the energy analyst to use in segmentation of the metropolitan area of telecommunications networks is proposed. The model is built to address the problem of inconsistent modelling in the energy literature... more
    An implementational model for the energy analyst to use in segmentation of the metropolitan area of telecommunications networks is proposed. The model is built to address the problem of inconsistent modelling in the energy literature (litera-ture that contributes to knowledge about energy absorption in large public networks). Two aspects of this problem are dealt with. Firstly, existing models are classified in ascending order of resolution. Within each class, the models are reconciled where possible but otherwise filtered according to where the mass of substantial agreement lies. Secondly, we describe the models using reference points for interconnection to strike a balance between abstraction and implementation. We further address this need for balance through emphasis on the transport function of the network. To facilitate the model's use, we develop it in accordance with frameworks defined in international standards and recommendations. We consolidate reference points for in...

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