IEEE Transactions on Aerospace and Electronic Systems, Nov 30, 2023
The Licklider Transport Protocol (LTP) has been designed to cope with long-delay and error-prone ... more The Licklider Transport Protocol (LTP) has been designed to cope with long-delay and error-prone scheduled-intermittent links, and thus is envisaged as the Bundle Protocol (BP) "convergence layer" of choice in future Inter-planetary networks (IPN) based on the Delay-/Disruption-Tolerant architecture. Moreover, LTP's remarkable ability to cope with multiple losses when operating in "red" reliable mode also makes it potentially appealing when coupled with Near Earth optical links. The aim of this paper is to assess LTP performance in this scenario, so we have developed a test bed based on real machines, real implementations of BP and LTP, and a channel emulator; this is based on "erasure vectors", i.e. time series describing the on/off state of the optical link, derived from real data measurements conducted by DLR. Our results show that, when properly configured, LTP is able to use all available bandwidth even under the most severe conditions, which makes it a perfect match to Near Earth Optical links.
Recent natural and man-made disasters have affected multiple disaster management organizations, s... more Recent natural and man-made disasters have affected multiple disaster management organizations, spanning multiple jurisdictions and countries. Examples are the extreme forest fires in France in 2016 and Portugal in 2017 and widespread flood events in Austria and the Czech Republic in 2013 and in Serbia and Croatia in 2014. Following the initial disaster event, cascading effects can further amplify the degree and complexity of disaster situations. This imposes a high demand of intra-and cross-organizational communication and cooperation-not only during the response phase, but increasingly also in the preparedness phase. An effective coordinated response requires a cohesive situation and risk assessment based on reliable information and a reasonable strategy and plan formulation. Our goal is to design and develop a system for improving response planning strategies and scenario building and facilitating organizational coordination among many actors. The designed solution includes a wide range of support tools to be used operationally by a large variety of stakeholders (firefighting units, medical emergency services, police departments, civil protection units and Command and Control Centres) and was designed with active participation of end users from these fields. In this regard, this work-in-progress paper presents and explains the design methodology chosen, the architecture and tools of the system developed in the ongoing EU H2020 project HEIMDALL.
Nowadays, the realization and the deployment of network infrastructures able to guarantee connect... more Nowadays, the realization and the deployment of network infrastructures able to guarantee connectivity to geographical areas characterized by hazardous access conditions, such as remote sensor networks, disaster areas and interplanetary networks, are assuming great importance. Under this view, the large access latencies along with the high percentage of lost packets makes the applicability of TCP/IP protocol suite almost unfeasible. A promising solution counteracting TCP/IP shortcomings is represented by the delay tolerant network (DTN) architecture, which exploits the principle of the mail delivery service to guarantee the success of the information transfer. This paper applies the DTN concepts to data communications achieved in deep space environments and investigates the adoption of error control schemes implemented at the higher layers, in order to make the transmission more reliable without the need of a feedback link for the acknowledgment transportation
Optimizing the optical feeder-links is essential in providing broadband connectivity between grou... more Optimizing the optical feeder-links is essential in providing broadband connectivity between ground and space. The system architecture is being investigated and experiments are being performed to integrate B5G technologies. Atmospheric turbulence mitigation is being demonstrated to provide a stable feeder-link and maximize the data throughput.
New generations of public safety communications will be building on the top of LTE technologies, ... more New generations of public safety communications will be building on the top of LTE technologies, taking advantage of its improved performance in capacity and quality of service. LTE networks present a unique opportunity to provide innovative applications and networking solutions to first responders. Flexible LTE deployments using satellite backhauling are being investigated raising new challenges regarding the integration of these technologies. In this paper, a delay-tolerant approach for different priorities of traffic management in LTE cell interconnected using satellite backhauling is presented. Long propagation delays and frequent disruptions of satellite links bring several challenges, especially to map the LTE quality of service requirements for traffic. We design and evaluate Disruption Management Agent (DMA), which acts as bridge between LTE and satellite technologies for providing end-to-end Quality of Service (QoS). Simulations results using several scenarios have shown the effectiveness of our solution to deliver an appropriate quality of service to first responders.
The increasing demand for mobile services has been calling for new anywhere-anytime communication... more The increasing demand for mobile services has been calling for new anywhere-anytime communication paradigms, building on the integration of heterogeneous technologies, such as satellite, LTE, and the new generation of mobile networks, i.e., 5G. In particular, the network design philosophy has shifted towards a more content-oriented approach so as to more efficiently meet the users' demands in terms of fast content availability and service continuity. Following this line, this paper proposes an enhancement to the PURSUIT information centric network (ICN) architecture, so as to improve the quality of experience of users in highly mobile environments. Simulation campaigns show the performance gain offered by the proposed solution with respect to regular PURSUIT implementations and benchmark IP-based strategies.
Offering very large data rates is one of the main objectives of Very High Throughput Satellite (V... more Offering very large data rates is one of the main objectives of Very High Throughput Satellite (VHTS) systems to boost enhanced Mobile Broadband (eMBB) services in converged 5G-satellite systems. To this end, the exploitation of Q/V frequency bands for the satellite feeder link is a key factor for guaranteeing unprecedented data rates provided that efficient handover algorithms are implemented to counteract link outage events caused by severe weather impairments. Moreover, Quality of Service (QoS) of data flows is typically affected when gateway handover is initiated, hence calling for sophisticated ground segment management solutions. In this light, this paper proposes a novel gateway handover strategy and validates its design through simulation campaigns, whose preliminary results show important performance gains with respect to other solutions available from the existing literature.
The long-term throughput of optical links between a circular-LEO satellite and a ground station i... more The long-term throughput of optical links between a circular-LEO satellite and a ground station is assessed for systems with fixed and variable data rates. For a fixed data rate, we evaluate the minimum elevation angle above which the link should be established in order to maximize the throughput. The ratio of this optimized constant-data-rate throughput to the throughput of an adaptive transmission with a data rate proportional to the received power is found to depend mainly on the satellite altitude.
The increasing demand for high-rate broadcast and multicast services over satellite networks has ... more The increasing demand for high-rate broadcast and multicast services over satellite networks has pushed for the development of High Throughput Satellites characterized by a large number of beams (e.g., more than 100). This, together with the variable distribution of data traffic request across beams and over time, has called for the design of a new generation of satellite payloads, able to flexibly allocate bandwidth and power. In this context, this paper studies the problem of radio resource allocation in the forward link of multibeam satellite networks adopting the Digital Video Broadcasting-Satellite-Second Generation (DVB-S2) standard. We propose a novel objective function with the aim to meet as close as possible the requested traffic across the beams while taking fairness into account. The resulting non-convex optimization problem is solved using a modified version of the simulated annealing algorithm, for which a detailed complexity analysis is presented. Simulation results obtained under realistic conditions confirm the effectiveness of the proposed approach and shed some light on possible payload design implications.
Support of data communication during disaster management operations is traditionally achieved by ... more Support of data communication during disaster management operations is traditionally achieved by means of Internet Protocol (IP)-based networks, which however show some limitation in terms of mobility support and resilience to link disruption. A new promising networking paradigm is represented by Information Centric Networking (ICN) architectures implementing caching functions, which are studied in this paper for their potentials to support emergency communications in integrated satellite-terrestrial networks. Simulation campaigns show the advantages offered by the Named Data Networking (NDN) architecture in terms of delivery latency and overall gain in comparison to IP-based architectures.
IEEE Transactions on Vehicular Technology, Oct 1, 2020
The integration of satellite communications into 5G ecosystem is pivotal to boost enhanced mobile... more The integration of satellite communications into 5G ecosystem is pivotal to boost enhanced mobile broadband (eMBB) services in highly dynamic scenarios and in areas not optimally supported by terrestrial infrastructures. Given the heterogeneity of the networks involved, network slicing is key networking paradigm to ensure different grades of quality of service (QoS) based on the users’ and verticals’ requirements. In this light, this paper proposes an optimisation framework able to exploit the available resources allocated to the defined network slices so as to meet the diverse QoS/QoE requirements exposed by the network actors. Resource allocation schemes built upon neural network algorithms are validated through extensive simulation campaigns that have shown the superiority of the proposed concepts with respect to other solution candidates available from the literature.
IEEE Transactions on Aerospace and Electronic Systems, Nov 30, 2023
The Licklider Transport Protocol (LTP) has been designed to cope with long-delay and error-prone ... more The Licklider Transport Protocol (LTP) has been designed to cope with long-delay and error-prone scheduled-intermittent links, and thus is envisaged as the Bundle Protocol (BP) "convergence layer" of choice in future Inter-planetary networks (IPN) based on the Delay-/Disruption-Tolerant architecture. Moreover, LTP's remarkable ability to cope with multiple losses when operating in "red" reliable mode also makes it potentially appealing when coupled with Near Earth optical links. The aim of this paper is to assess LTP performance in this scenario, so we have developed a test bed based on real machines, real implementations of BP and LTP, and a channel emulator; this is based on "erasure vectors", i.e. time series describing the on/off state of the optical link, derived from real data measurements conducted by DLR. Our results show that, when properly configured, LTP is able to use all available bandwidth even under the most severe conditions, which makes it a perfect match to Near Earth Optical links.
Recent natural and man-made disasters have affected multiple disaster management organizations, s... more Recent natural and man-made disasters have affected multiple disaster management organizations, spanning multiple jurisdictions and countries. Examples are the extreme forest fires in France in 2016 and Portugal in 2017 and widespread flood events in Austria and the Czech Republic in 2013 and in Serbia and Croatia in 2014. Following the initial disaster event, cascading effects can further amplify the degree and complexity of disaster situations. This imposes a high demand of intra-and cross-organizational communication and cooperation-not only during the response phase, but increasingly also in the preparedness phase. An effective coordinated response requires a cohesive situation and risk assessment based on reliable information and a reasonable strategy and plan formulation. Our goal is to design and develop a system for improving response planning strategies and scenario building and facilitating organizational coordination among many actors. The designed solution includes a wide range of support tools to be used operationally by a large variety of stakeholders (firefighting units, medical emergency services, police departments, civil protection units and Command and Control Centres) and was designed with active participation of end users from these fields. In this regard, this work-in-progress paper presents and explains the design methodology chosen, the architecture and tools of the system developed in the ongoing EU H2020 project HEIMDALL.
Nowadays, the realization and the deployment of network infrastructures able to guarantee connect... more Nowadays, the realization and the deployment of network infrastructures able to guarantee connectivity to geographical areas characterized by hazardous access conditions, such as remote sensor networks, disaster areas and interplanetary networks, are assuming great importance. Under this view, the large access latencies along with the high percentage of lost packets makes the applicability of TCP/IP protocol suite almost unfeasible. A promising solution counteracting TCP/IP shortcomings is represented by the delay tolerant network (DTN) architecture, which exploits the principle of the mail delivery service to guarantee the success of the information transfer. This paper applies the DTN concepts to data communications achieved in deep space environments and investigates the adoption of error control schemes implemented at the higher layers, in order to make the transmission more reliable without the need of a feedback link for the acknowledgment transportation
Optimizing the optical feeder-links is essential in providing broadband connectivity between grou... more Optimizing the optical feeder-links is essential in providing broadband connectivity between ground and space. The system architecture is being investigated and experiments are being performed to integrate B5G technologies. Atmospheric turbulence mitigation is being demonstrated to provide a stable feeder-link and maximize the data throughput.
New generations of public safety communications will be building on the top of LTE technologies, ... more New generations of public safety communications will be building on the top of LTE technologies, taking advantage of its improved performance in capacity and quality of service. LTE networks present a unique opportunity to provide innovative applications and networking solutions to first responders. Flexible LTE deployments using satellite backhauling are being investigated raising new challenges regarding the integration of these technologies. In this paper, a delay-tolerant approach for different priorities of traffic management in LTE cell interconnected using satellite backhauling is presented. Long propagation delays and frequent disruptions of satellite links bring several challenges, especially to map the LTE quality of service requirements for traffic. We design and evaluate Disruption Management Agent (DMA), which acts as bridge between LTE and satellite technologies for providing end-to-end Quality of Service (QoS). Simulations results using several scenarios have shown the effectiveness of our solution to deliver an appropriate quality of service to first responders.
The increasing demand for mobile services has been calling for new anywhere-anytime communication... more The increasing demand for mobile services has been calling for new anywhere-anytime communication paradigms, building on the integration of heterogeneous technologies, such as satellite, LTE, and the new generation of mobile networks, i.e., 5G. In particular, the network design philosophy has shifted towards a more content-oriented approach so as to more efficiently meet the users' demands in terms of fast content availability and service continuity. Following this line, this paper proposes an enhancement to the PURSUIT information centric network (ICN) architecture, so as to improve the quality of experience of users in highly mobile environments. Simulation campaigns show the performance gain offered by the proposed solution with respect to regular PURSUIT implementations and benchmark IP-based strategies.
Offering very large data rates is one of the main objectives of Very High Throughput Satellite (V... more Offering very large data rates is one of the main objectives of Very High Throughput Satellite (VHTS) systems to boost enhanced Mobile Broadband (eMBB) services in converged 5G-satellite systems. To this end, the exploitation of Q/V frequency bands for the satellite feeder link is a key factor for guaranteeing unprecedented data rates provided that efficient handover algorithms are implemented to counteract link outage events caused by severe weather impairments. Moreover, Quality of Service (QoS) of data flows is typically affected when gateway handover is initiated, hence calling for sophisticated ground segment management solutions. In this light, this paper proposes a novel gateway handover strategy and validates its design through simulation campaigns, whose preliminary results show important performance gains with respect to other solutions available from the existing literature.
The long-term throughput of optical links between a circular-LEO satellite and a ground station i... more The long-term throughput of optical links between a circular-LEO satellite and a ground station is assessed for systems with fixed and variable data rates. For a fixed data rate, we evaluate the minimum elevation angle above which the link should be established in order to maximize the throughput. The ratio of this optimized constant-data-rate throughput to the throughput of an adaptive transmission with a data rate proportional to the received power is found to depend mainly on the satellite altitude.
The increasing demand for high-rate broadcast and multicast services over satellite networks has ... more The increasing demand for high-rate broadcast and multicast services over satellite networks has pushed for the development of High Throughput Satellites characterized by a large number of beams (e.g., more than 100). This, together with the variable distribution of data traffic request across beams and over time, has called for the design of a new generation of satellite payloads, able to flexibly allocate bandwidth and power. In this context, this paper studies the problem of radio resource allocation in the forward link of multibeam satellite networks adopting the Digital Video Broadcasting-Satellite-Second Generation (DVB-S2) standard. We propose a novel objective function with the aim to meet as close as possible the requested traffic across the beams while taking fairness into account. The resulting non-convex optimization problem is solved using a modified version of the simulated annealing algorithm, for which a detailed complexity analysis is presented. Simulation results obtained under realistic conditions confirm the effectiveness of the proposed approach and shed some light on possible payload design implications.
Support of data communication during disaster management operations is traditionally achieved by ... more Support of data communication during disaster management operations is traditionally achieved by means of Internet Protocol (IP)-based networks, which however show some limitation in terms of mobility support and resilience to link disruption. A new promising networking paradigm is represented by Information Centric Networking (ICN) architectures implementing caching functions, which are studied in this paper for their potentials to support emergency communications in integrated satellite-terrestrial networks. Simulation campaigns show the advantages offered by the Named Data Networking (NDN) architecture in terms of delivery latency and overall gain in comparison to IP-based architectures.
IEEE Transactions on Vehicular Technology, Oct 1, 2020
The integration of satellite communications into 5G ecosystem is pivotal to boost enhanced mobile... more The integration of satellite communications into 5G ecosystem is pivotal to boost enhanced mobile broadband (eMBB) services in highly dynamic scenarios and in areas not optimally supported by terrestrial infrastructures. Given the heterogeneity of the networks involved, network slicing is key networking paradigm to ensure different grades of quality of service (QoS) based on the users’ and verticals’ requirements. In this light, this paper proposes an optimisation framework able to exploit the available resources allocated to the defined network slices so as to meet the diverse QoS/QoE requirements exposed by the network actors. Resource allocation schemes built upon neural network algorithms are validated through extensive simulation campaigns that have shown the superiority of the proposed concepts with respect to other solution candidates available from the literature.
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Papers by Tomaso de Cola