Giovanni Stea

Università di Pisa | UNIPI · Department of Information Engineering

[A PDF of this paper is available at: http://info.iet.unipi.it/~stea/] [The code is available at: http://www.simulte.com] This paper describes SimuLTE, an open-source system-level simulator for LTE and LTE-Advanced (LTE-A) networks. SimuLTE is based on OMNeT++, a well-known, widely-used modular simulation framework, which offers a high degree of e...

Real-time emulation of 5G networks is highly beneficial for several purposes, such as prototyping or performance evaluation of distributed applications meant to run on 5G networks, research demonstration, evaluation of other technologies (e.g., Multi-access Edge Computing) meant to interoperate with 5G access. In this work, we describe how to use S...

In this paper we introduce Simu5G, a new OMNeT++-based model library to simulate 5G networks. Si-mu5G allows users to simulate the data plane of 5G New Radio deployments, in an end-to-end perspective and including all protocol layers, making it a valuable tool for researchers and practitioners interested in the performance evaluation of 5G networks...

Open-access full text here: http://www.mdpi.com/1424-8220/18/5/1527 Abstract: Platooning is a cooperative driving application where autonomous/semi-autonomous vehicles move on the same lane in a train-like manner, keeping a small constant inter-vehicle distance, in order to reduce fuel consumption and gas emissions and to achieve safe and efficien...

In recent years, the need for computation-intensive applications in mobile networks requiring more storage, powerful processors, and real-time responses has risen substantially. Vehicular networks play an important role in this ecosystem, as they must support multiple services, such as traffic monitoring or sharing of data involving different aspec...

Network Calculus (NC) is an algebraic theory that represents traffic and service guarantees as curves in a Cartesian plane, in order to compute performance guarantees for flows traversing a network. NC uses transformation operations, e.g., min-plus convolution of two curves, to model how the traffic profile changes with the traversal of network nod...

We consider a scheduling application in 5G cellular networks, where base stations serve periodic tasks by allocating conflict-free portions of the available spectrum, in order to meet their traffic demand. The problem has a combinatorial structure featuring bi-dimensional periodic allocations of resources. We consider four variants of the problem,...

Multi-access Edge Computing (MEC) is expected to support platooning of vehicles, by running the control logic that computes the acceleration values of the vehicles based on their position and speed. Connectivity between vehicles and the MEC system is likely to be realized through the mobile network. However, platoons will be composed of vehicles th...

Networks with hop-by-hop flow control occur in several contexts, from data centers to systems architectures (e.g., wormhole-routing networks on chip). A worst-case end-to-end delay in such networks can be computed using Network Calculus (NC), an algebraic theory where traffic and service guarantees are represented as curves in a Cartesian plane. NC...

Researchers working on Artificial Intelligence (AI) need suitable datasets for training and testing their models. When it comes to applications running through a mobile network, these datasets are difficult to obtain, because network operators are hardly willing to expose their network data or to open their network to experimentation. In this paper...

The Multi-access Edge Computing (MEC) standard of the European Telecommunications Standards Institute (ETSI) will enable context-aware services for users of mobile 4G/5G networks. ETSI MEC application developers need tools to aid the design and the performance evaluation of their apps. During the early stages of deployment, they should be able to e...

A method for managing data packets (MAC PDUtx, RLC PDUtx) transmitted by a first user equipment (105tx) to be received by a second user equipment (105rx) through a radio network is proposed. The method comprising having the radio network comprising a radio transceiver station (110) configured for receiving data packets (MAC PDUtx; RLC PDUtx) transm...

This article presents the concept of federated learning (FL) of eXplainable Artificial Intelligence (XAI) models as an enabling technology in advanced 5G towards 6G systems and discusses its applicability to the automated vehicle networking use case. Although the FL of neural networks has been widely investigated exploiting variants of stochastic g...

A method for managing data packets (IP PDUtx, PDCP PDUtx, RLC PDUtx, MAC PDUtx) transmitted by a first user equipment (105tx) to be received by a second user equipment (105rx) is proposed. The first user equipment (105tx) is arranged for communicating with the second user equipment (105rx) in a direct mode by directly connecting to the second user...

Blockchain (BC) technology has recently emerged as an essential component for different applications, including healthcare and IoT, because of its decentralized ledger, source provenance, and tamper-proof nature. The Internet of Things (IoT) and BC have enabled health systems to expand their scalability and maintain consistency on a decentralized p...

The Dynamic Random Access Memory (DRAM) is among the major points of contention in multi-core systems. We consider a challenging optimization problem arising in worstcase performance analysis of systems architectures: computing the worst-case delay (WCD) experienced when accessing the DRAM due to the interference of contending requests. The WCD is...

This paper describes Nancy, a Network Calculus (NC) library that allows users to perform complex min-plus and max-plus algebra operations efficiently. To the best of our knowledge, Nancy is the only open-source library that implements operations working on arbitrary piecewise affine functions, as well as to implement some of them (e.g. sub-additive...

Acute Encephalitis Syndrome (AES) is a serious, life-threatening disease, which is endemic in India and South-East Asia, where it adds to the strain on healthcare systems. It is a communicable disease that is caused by a virus attacking the brain tissues. The main objective of this study is to present a system that allows for monitoring, controllin...

Network Calculus (NC) is an algebraic theory that represents traffic and service guarantees as curves in a Cartesian plane, in order to compute performance guarantees for flows traversing a network. NC uses transformation operations, e.g., min-plus convolution of two curves, to model how the traffic profile changes with the traversal of network nod...

Network Calculus (NC) is an algebraic theory that represents traffic and service guarantees as curves in a Cartesian plane, in order to compute performance guarantees for flows traversing a network. NC uses transformation operations, e.g., min-plus convolution of two curves, to model how the traffic profile changes with the traversal of network nod...

This paper describes Nancy, a Network Calculus (NC) library that allows users to perform complex min-plus and max-plus algebra operations efficiently. To the best of our knowledge, Nancy is the only open-source library that implements operators working on arbitrary piecewise-linear functions (as opposed to only concave/convex ones), as well as to i...

An apparatus 100 comprising interface circuitry 105 to receive memory access commands directed to a memory device, each memory access command specifying a memory address to be accessed. Scheduler circuitry 110 stores a representation of a plurality of states accessible to the memory device 115 and, based on the representation, determine an order fo...

Multi-access Edge Computing (MEC) will enable context-aware services for users of mobile 4G/5G networks. MEC application developers need tools to aid the design and the performance evaluation of their apps. During the early stages of deployment, they should be able to evaluate the performance impact of design choices - e.g., what round-trip delay c...

Networks with hop-by-hop flow control occur in several contexts, from data centers to systems architectures (e.g., wormhole-routing networks on chip). A worst-case end-to-end delay in such networks can be computed using Network Calculus (NC), an algebraic theory where traffic and service guarantees are represented as curves in a Cartesian plane. NC...

Recently, there has been a substantial amount of research on smart classrooms, encompassing a number of areas, including Information and Communication Technology, Machine Learning, Sensor Networks, Cloud Computing, and Hardware. Smart classroom research has been quickly implemented to enhance education systems, resulting in higher engagement and em...

COVID-19 has recently manifested as one of the most serious life-threatening infections and is still circulating globally. COVID-19 can be contained to a considerable extent if a patient can know their COVID-19 infection at a possible earlier time, and they can be isolated from other individuals Recently, researchers have explored AI (Artificial In...

In critical alert services (e.g., a collision alert in a vehicular network) a message must reach all the recipients in a prespecified area within a maximum time, usually of few milliseconds, with guaranteed reliability. In this paper, we consider a Device-to-device (D2D)-enabled cellular network where User Equipments (UEs) use D2D transmissions to...

Multi-access Edge Computing (MEC) is expected to act as the enabler for the integration of 5G (and future 6G) communication technologies with cloud-computing-based capabilities at the edge of the network. This will enable low-latency and context-aware applications for users of such mobile networks. In this paper we describe the implementation of a...

Multi-access Edge Computing (MEC) is expected to act as the enabler for the integration of 5G (and future 6G) communication technologies with cloud-computing-based capabilities at the edge of the network. This will enable low-latency and context-aware applications for users of such mobile networks. In this paper we describe the implementation of a...

This paper describes the SAPIENT system, a real-time monitoring and control infrastructure for Air Traffic Man-agement. Within the latter, aircrafts constantly measure the state and quality of their datalinks, and report these measurements to a ground entity, tagging them with a time/space reference. The ground entity, then, builds a map of the mon...

We verified that Simu5G can run in emulation mode, by connecting real application endpoints to modules in a simulation and having the simulation run in real time. We verified that Simu5G can emulate up to 10 cells and 1000 users on a desktop machine.

Due to the trends of centralizing the E/E architecture and new computing-intensive applications, high-performance hardware platforms are currently finding their way into automotive systems. However, the Systems-on-Chip (SoCs) currently available on the market have significant weaknesses when it comes to providing predictable performance for time-cr...

Multi-access Edge Computing (MEC) promises to deliver localized computing power and storage. Coupled with low-latency 5G radio access, this enables the creation of high added-value services for mobile users, such as in-vehicle infotainment or remote driving. The performance of these services as well as their scalability will however depend on how M...

Mobile cellular networks play a pivotal role in emerging Internet of Things (IoT) applications, such as vehicular collision alerts, malfunctioning alerts in Industry-4.0 manufacturing plants, periodic distribution of coordination information for swarming robots or platooning vehicles, etc. All these applications are characterized by the need of rou...

Multi-access Edge Computing (MEC) allows users to run appli-cations on demand near their mobile access points. MEC appli-cations will exploit 5G infrastructure, and they will have to be designed by taking into account the characteristics of 5G mobile networks. This work describes how to use a system-level simula-tor of 5G networks – namely Simu5G,...

This paper presents Simu5G, a new OMNeT++-based system-level simulator of 5G networks. Simu5G is built starting from the SimuLTE simulation library, which models 4G (i.e., LTE/LTE-A) networks, and is compatible with the latter, thus allowing the simulation of 4G-5G coexistence and transition scenarios. We discuss the modelling of the protocol layer...

Evaluating edge deployments from a user perspective requires modeling, in a unified framework, the communication part, i.e., the cellular access network, and the computation part, i.e., the Mobile-edge server. This paper presents a framework that enables this, by joining the SimuLTE 4G network simulator and the Intel CoFluent edge-computing simulat...

Computing Systems are evolving towards more complex, hetero-geneous systems where multiple computing cores and accelerators on the same system concur to improve computing resources utili-zation, resources re-use and the efficiency of data sharing across workloads. Such complex systems require equally complex tools and models to design and engineer...

Mobile cellular networks play a pivotal role in emerging Internet of Things (IoT) applications, such as vehicular collision alerts, malfunctioning alerts in Industry-$4.0$ manufacturing plants, periodic distribution of coordination information for swarming robots or platooning vehicles, etc. All these applications are characterized by the need of r...

Heterogeneous systems, composed of a variety of devices, are especially difficult to design and dimension for target use-cases. There is a pressing need for tools that can facilitate the exploration of their design space, so that designers and testers can be allowed to predict or measure performance on their target use-cases. On the other hand, a n...

Multi-access edge computing (MEC) brings data and computational resources near mobile users, with the ultimate goal of reducing latency, improving resource utilization, and leveraging context and radio awareness. Relocation policies for applications in the MEC environment are necessary to guarantee its effectiveness and performance, and can use a m...

We call “Interconnected Systems” any collection of systems distributed over a metric space whose behavior is influenced by its neighborhood. Examples of interconnected systems exist at very different scales: different cores over the same silicon, different sub-systems in vehicles, communicating nodes over either a physical (e.g., optical) network,...

Multi-access Edge Computing (MEC) brings data and computational resources near mobile users, with the ultimate goal ofreducing latency, improving resource utilization and leveraging context- and radio-awareness. Relocation policies for applicationsin the MEC environment are necessary to guarantee its effectiveness and performance, and can use a mul...

This chapter describes SimuLTE, a framework within the OMNeT++ ecosystem for simulating Long Term Evolution (LTE) networks. The main focus of SimuLTE lies on developing and testing of communication protocols and resource-allocation algorithms, with an emphasis on the impact at the system level. The chapter starts with a detailed description of the...

In Long Term Evolution-Advanced (LTE-A), network-controlled device-to-device (D2D) communications allow User Equipments (UEs) to communicate directly, without involving the Evolved Node-B in data relaying, while the latter still retains control of resource allocation. The above paradigm allows reduced latencies for the UEs and increased resource ef...

Over the next few years, future aeronautical communications are expected to move from the OSI protocol stack to the TCP/IP one. Multiple data-link channels (e.g., satellite, terrestrial) will be available to each aircraft to communicate with ground, realizing the so-called multilink. In order to ensure a seamless handover between different data-lin...

Multi-access Edge Computing (MEC) is a novel paradigm to enrich current 4G and future 5G cellular networks by placing cloud-computing-based capabilities at the edge of the network. This will allow operators and service providers to endow the cellular network with enriched services. In this paper we describe the modeling and development of a MEC ext...

5G networks will have to offer extremely high volumes of content, compared to today’s. Moreover, they will have to support heterogeneous traffics, including Machine-to-machine, generated by a massive volume of Internet-of-Things devices. Traffic demands will be variable in time and space. In this work, we argue that all this can be achieved in a co...

Delay-Constrained Routing (DCR) problems require to route a new flow in a computer network subject to worst-case end-to-end delay guarantees. The delay of a packet flow has three components, one of which is the queueing delay, that depends on the scheduling algorithm implemented by the routers of the network. When flows are not independent of each...

Cellular network nodes should be dynamically switched on/off based on the load requirements of the network, to save power and minimize inter-cell interference. This should be done keeping into account global interference effects, which requires a centralized approach. In this paper, we present an architecture, realized within the Flex5GWare EU proj...

Point-to-multipoint device-to-device (P2MP D2D) communications have been standardized in LTE-Advanced (LTE-A) for proximity-based services, such as advertisement and public safety. They can be combined in a multi-hop fashion to achieve geofenced broadcasts in a fast and reliable way, over areas possibly covered by several cells [17]. This allows LT...

Fog computing is envisaged as the evolution of the current cen-tralized cloud to support the forthcoming Internet of Things (IoT) revolution. While IoT devices will still communicate with applications running in the cloud, localized fog clusters, with IoT devices communicating with application logic running on a proximate fog node, will also appear...

Coordinated Scheduling (CS) is used to mitigate inter-cell interference in present (4G) and future (5G) cellular networks. We show that coordination of a cluster of nodes can be formulated as an optimization problem, i.e., placing the Resource Blocks (RB) in each node’s subframe with the least possible over-lapping with neighboring nodes. We provid...

One-to-one device-to-device (D2D) communications are expected to play a major role in future releases of LTE-A, as well as in future 5G networks. Despite the abundance of works on resource allocation for D2D communications, few works, if any, discuss how D2D should be realized within the LTE-A protocol stack. While it is generally understood that D...

Several applications, from Internet of Things for smart cities to those for vehicular networks, need fast and reliable proximity-based broadcast communications, i.e. the ability to reach all peers in a geographical neighborhood around the originator of a message, as well as ubiquitous connectivity. In this paper, we point out the inherent limitatio...

The SESAR (Single European Sky ATM Research) Exploratory Research project called SAPIENT (Satellite and terrestrial architectures improving performance, security and safety in ATM) is a program of the SESAR Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement 699328 [1][2]. It aims at def...

Future aeronautical communications will be based on the TCP/IP protocol stack, and will occur through a number of different data-link channels (e.g., satellite, terrestrial), with multipath capabilities – the so-called multilink. Seamless vertical handover between different data-links is a requirement and it will improve the safety and reliability...

[The paper is available at the following link: https://arxiv.org/pdf/1709.02208.pdf] The evolution of cellular technologies toward 5G progressively enables efficient and ubiquitous communications in an increasing number of fields. Among these, vehicular networks are being considered as one of the most promising and challenging applications, requir...

Almost Blank Subframes (ABSs) have been defined in LTE as a means to coordinate transmissions in heterogeneous networks (HetNets), composed of macro and micro eNodeBs: the macro issues ABS periods, and refrains from transmitting during ABSs, thus creating interference-free subframes for the micros. Micros report their capacity demands to the macro...

Coordinated Scheduling (CS) is one of the main techniques to control inter-cell interference in present (4G) and future (5G) cellular networks. We show that coordination of a cluster of nodes can be formulated as an optimization problem, i.e., placing the Resource Blocks in each node’s subframe with the least possible overlapping with neighboring n...

This paper describes the software architecture and the implementation of a fully operational testbed that demonstrates the benefits of flexible, dynamic resource allocation with virtualized LTE-A nodes. The testbed embodies and specializes the general software architecture devised within the Flex5Gware EU project, and focuses on two intelligent pro...

The need for massive content delivery is a consolidated trend in mobile communications, and will even increase for next years. Moreover, while 4G maturity and evolution is driven by video contents, next generation (5G) networks will be dominated by heterogeneous data and additional massive diffusion of Internet of Things (IoT). The current network...

This paper presents a framework to activate and deactivate micro nodes in a heterogeneous multi-cell LTE network, based on load and energy efficiency consideration. The framework exploits historical data (i.e., per-macro-cell load curves) to select a set of candidate switch-on/switch-off instants of micro cells, assuming a limited number of state c...

Using Coordinated Scheduling (CS), eNodeBs in a cellular network dynamically agree on which Resource Blocks (not) to use, so as to reduce the interference, especially for celledge users. This paper describes a software framework that allows dynamic CS to occur among a relatively large number of nodes, as part of a more general framework of network...

In a network where weighted fair-queueing schedulers are used at each link, a flow is guaranteed an end-to-end worst-case delays which depends on the rate reserved for it at each link it traverses. Therefore, it is possible to compute resource-constrained paths that meet target delay constraints, and optimize some key performance metrics (e.g., min...

As shown in [1], the problem of routing a flow subject to a worst-case end-to-end delay constraint in a packed-based network can be formulated as a Mixed-Integer Second-Order Cone Program, and solved with general-purpose tools in real time on realistic instances. However, that result only holds for one particular class of packet schedulers, Strictl...

[The full paper is available at http://dx.doi.org/10.1007/s11276-016-1193-3 and http://info.iet.unipi.it/~stea/] Network-controlled device-to-device (D2D) communication allows cellular users to communicate directly, i.e., without passing through the eNodeB, while the latter retains control over resource allocation. This allows the same time-freque...

A method of broadcasting a message (m) among user equipment (UE0-8) in a broadcast area (115; 515) covered by a wireless communication network (100) is proposed. The wireless communication network comprises at least one radio base station (105; 420, 425; 505A-E) which is adapted to manage communications of user equipment in one or more respective s...

Future 5G cellular networks are expected to play a major role in supporting the future Internet of Things (IoT), due to their ubiquitous coverage, plug-and-play configuration and embedded security. Besides connectivity, however, IoT will need computation and storage in proximity of sensors and actuators to support time-critical and opportunistic ap...

SimuLTE is a tool that enables system-level simulations of LTE/LTE-Advanced networks within OMNeT++. It is designed such that it can be plugged within network elements as an additional Network Interface Card (NIC) to those already provided by the INET framework (e.g. Wi-Fi). Recently, device-to-device (D2D) technology has been widely studied by the...

[The full PDF can be downloaded here: http://www.iet.unipi.it/g.stea/Research/papers/D2D_PIMRC-open_access.pdf] In an LTE-Advanced network, network-controlled Device-to-Device (D2D) communications can be combined in a multihop fashion to distribute broadcasts over user-defined (and possibly large) areas, with small latencies and occupying few reso...