Routing Strategies and Content Dissemination Techniques for Software-Defined Vehicular Networks

Doctoral thesis (2020)

Over the past years, vehicular networking has enabled a wide range of new applications that improve vehicular safety, efficiency, comfort, and environmental impact. Vehicular networks, however, normally ... [more ▼]

Over the past years, vehicular networking has enabled a wide range of new applications that improve vehicular safety, efficiency, comfort, and environmental impact. Vehicular networks, however, normally operate in communication-hostile environments and are characterized by dynamic topologies and volatile links, making it challenging to guarantee Quality of Service (QoS) and reliability of vehicular applications. To this end, the present work explores how the centralized coordination offered by Software-Defined Networking can improve the Quality of Service in vehicular networks, particularly for Vehicle-to-Vehicle (V2V) unicast routing and content dissemination. With regard to V2V routing, this work motivates the case for centralized network coordination by studying the performance of traditional MANET routing protocols when applied to urban VANETs, showing that they cannot provide satisfactory performance for modern vehicular applications because of their limited global network awareness, slow convergence, and high signaling. Hence, this work proposes and validates a centralized Multi-Flow Congestion-Aware Routing (MFCAR) algorithm to allocate multiple data flows on V2V routes. The first novelty of MFCAR is the SDN-based node-busyness estimation technique. The second novelty is the enhancement of the path-cost formulation as a linear combination of path length and path congestion, allowing the user application to fine-tune its QoS requirements between throughput and delay. Concerning content dissemination, this work proposes a Fairness- and Throughput-Enhanced Scheduling for Content Dissemination in VANETs (ROADNET), a centralized strategy to improve the tradeoff between data throughput and user fairness in deterministic vehicular content dissemination. ROADNET’s main novelties are the design of a graph-based multi-channel transmission scheduler and the enforcement of a transmission-priority policy that prevents user starvation. As additional contributions, the present work proposes a heuristic for the centralized selection of opportunistic content dissemination parameters and discusses the main security issues in Software-Defined Vehicular Networking (SDVN) along with possible countermeasures. The proposed techniques are evaluated in realistic scenarios (LuST), using discrete-event network simulators (OMNeT++) and microscopic vehicular-mobility simulators (SUMO). It is shown that MFCAR can improve PDR, throughput and delay for unicast V2V routing up to a five-fold gain over traditional algorithms. ROADNET can increase content dissemination throughput by 36% and user fairness by 6% compared to state-of-the-art techniques, balancing the load over multiple channels with a variance below 1%. [less ▲]

Multi-flow congestion-aware routing in software-defined vehicular networks

in 2019 IEEE 90th Vehicular Technology Conference (VTC2019-Fall) Proceedings (2019, September 22)

5G-enabled vehicular networks will soon allow their users to exchange safety and non-safety related information over heterogeneous communication interfaces. Routing vehicular data flows over multi-hop ... [more ▼]

5G-enabled vehicular networks will soon allow their users to exchange safety and non-safety related information over heterogeneous communication interfaces. Routing vehicular data flows over multi-hop Vehicle-to-Vehicle (V2V) communications is one of the hardest challenges in vehicular networking, and it has been tackled in literature by using distributed algorithms. The distributed approach has shown significant inefficiencies in such dynamic vehicular scenarios, mainly due to poor network congestion control. To overcome the complexity of the envisioned architecture, and the inefficiency of distributed routing algorithms, we hereby propose to leverage the coordination capabilities of Software-Defined Networking (SDN) to determine optimal V2V multi-hop paths and to offload traffic from the Vehicle-to-Infrastructure-to-Vehicle (V2I2V) to the V2V communications, using both cellular and Wi-Fi technologies. In order to achieve this goal, we propose Multi-Flow Congestion-Aware Routing (MFCAR), a centralized routing algorithm that relies on graph theory to choose short and uncongested V2V paths. Realistic simulations prove that MFCAR outperforms well- established centralized routing algorithms (e.g. Dijkstra's) in terms of Packet Delivery Ratio (PDR), goodput and average packet delay, up to a five-fold performance gain. [less ▲]

A centralized approach for setting floating content parameters in VANETs

in A centralized approach for setting floating content parameters in VANETs (2017, July 20)

Floating Content (FC) has recently been proposed as an attractive application for mobile networks, such as VANETs, to operate opportunistic and distributed content sharing over a given geographic area ... [more ▼]

Floating Content (FC) has recently been proposed as an attractive application for mobile networks, such as VANETs, to operate opportunistic and distributed content sharing over a given geographic area, namely Anchor Zone (AZ). FC performances are tightly dependent on the AZ size, which in literature is classically chosen by the node that generates the floating message. In the present work, we propose a method to improve FC performances by optimizing the AZ size with the support of a Software Defined Network (SDN) controller, which collects mobility information, such as speed and position, of the vehicles in its coverage range. [less ▲]

Coordination Mechanisms for Floating Content in Realistic Vehicular Scenario

in Coordination Mechanisms for Floating Content in Realistic Vehicular Scenario (2017)

The increasing interest in vehicular communications draws attention to scalability and network congestion problems and therefore on techniques to offload the traffic, typically carried through the ... [more ▼]

The increasing interest in vehicular communications draws attention to scalability and network congestion problems and therefore on techniques to offload the traffic, typically carried through the infrastructure, to the Vehicle-to-vehicle (V2V) network. Floating content (FC) represents a promising paradigm to share ephemeral content without direct support from infrastructure. It is based on constraining geographically within the Anchor Zone (AZ) the opportunistic replication of a given content among vehicles, in a way that strikes a balance between minimization of resource usage and content availability. Existing works on FC performance modeling are based on standard, homogeneous synthetic mobility models, and it is hence unclear how they actually fit in realistic mobility scenarios. Moreover, the approaches to FC dimensioning they propose assume users have full knowledge of Spatio-temporal mobility patterns, which is hard to achieve in practice. Finally, despite FC is an infrastructure-less communication paradigm, some form of infrastructure support could be available in the vast majority of those application scenarios for which it has been proposed. In this paper, we perform a first attempt at tackling these issues. We focus on how to dimension an Anchor Zone in a realistic vehicular scenario. We propose the first set of simple dimensioning strategies, based on the estimation of some key mobility parameters and of FC performance. We assess such strategies on measurement-based vehicular traces, providing a first indication of their relative performance, and of the feasibility of FC in practical scenarios. [less ▲]

SDN coordination for CCN and FC content dissemination in VANETs

in Proceedings of the 8th International Conference on Ad Hoc Networks (ADHOCNETS), Ottawa, ON, Canada (2016, September 26)

Content dissemination in Vehicular Ad-hoc Networks has a myriad of applications, ranging from advertising and parking notifications, to traffic and emergency warnings. This heterogeneity requires ... [more ▼]

Content dissemination in Vehicular Ad-hoc Networks has a myriad of applications, ranging from advertising and parking notifications, to traffic and emergency warnings. This heterogeneity requires optimizing content storing, retrieval and forwarding among vehicles to deliver data with short latency and without jeopardizing network resources. In this paper, for a few reference scenarios, we illustrate how approaches that combine Content Centric Networking (CCN) and Floating Content (FC) enable new and efficient solutions to this issue. Moreover, we describe how a network architecture based on Software Defined Networking (SDN) can support both CCN and FC by coordinating distributed caching strategies, by optimizing the packet forwarding process and the availability of floating data items. For each scenario analyzed, we highlight the main research challenges open, and we describe a few possible solutions. [less ▲]

A computer vision and control algorithm to follow a human target in a generic environment using a drone

in Lecture Notes in Computer Science, Intelligent Computing Theories and Application (2016)

This work proposes an innovative technique to solve the problem of tracking and following a generic human target by a drone in a natural, possibly dark scene. The algorithm does not rely on color ... [more ▼]

This work proposes an innovative technique to solve the problem of tracking and following a generic human target by a drone in a natural, possibly dark scene. The algorithm does not rely on color information but mainly on shape information, using the HOG classifier, and on local brightness information, using the optical flow algorithm. We tried to keep the algorithm as light as possible, envisioning its future application on embedded or mobile devices. After several tests, performed modeling the system as a set of SISO feedback-controlled systems and calculating the Integral Squared Error as quality indicator, we noticed that the final performance, overall satisfactory, degrades as the background complexity and the presence of disturbance sources, such as sharp edges and moving objects that cross the target, increase . [less ▲]