An Age-Of-Information Perspective on Decentralized Congestion Control in Vehicular Networks

in 19th Mediterranean Communication and Computer Networking Conference, Online Conference, 15-17 June 2021 (2021, June)

Vehicular networking enables a wide range of emerging Cooperative Intelligent Transportation System (C-ITS) applications, from safety to traffic efficiency and infotainment. Many of these applications ... [more ▼]

Vehicular networking enables a wide range of emerging Cooperative Intelligent Transportation System (C-ITS) applications, from safety to traffic efficiency and infotainment. Many of these applications depend on the reliability and timeliness of status information periodically exchanged among vehicles on the same wireless communication channel. A major effort has been spent, especially by standardization bodies, to define congestion control algorithms for the vehicular networking environment. The picture is, however, more complex than simply controlling the load level on the channel, given the non-trivial interplay of delivery reliability, system throughput, and timeliness of updates. In this paper, we provide a comprehensive performance evaluation of the main state-of- the-art broadcast rate control algorithms from the point of view of channel load, utilization efficiency, and information freshness. We evaluate these algorithms in a realistic simulation environment and describe a centralized approach to define a bound on the performance. We show that controlling the congestion based on either channel load or information freshness only leads to sub-optimal performance. [less ▲]

Age of Information of One-Hop Broadcast Communications in a CSMA Network

in IEEE Communications Letters (2020), 25(1), 294-298

We consider a network of agents that send periodic updates to their neighbors. A trade-off between load on the shared communication channel and data timeliness is obtained by looking at the Age of ... [more ▼]

We consider a network of agents that send periodic updates to their neighbors. A trade-off between load on the shared communication channel and data timeliness is obtained by looking at the Age of Information (AoI) metric. We develop a model of a Carrier-Sense Multiple Access (CSMA) network with partial sensing, to calculate the AoI of one-hop broadcast messages exchanged among the agents. The model is applied to beacon messages in a vehicular network to gain insight into the impact of system parameters. [less ▲]

Softwarization of SCADA: Lightweight Statistical SDN-Agents for Anomaly Detection

in 10th International Conference on Networks of the Future (NoF) (2019, October 04)

The increasing connectivity of restricted areas suchas Critical Infrastructures (CIs) raises major security concernsfor Supervisory Control And Data Acquisition (SCADA) systems,which are deployed to ... [more ▼]

The increasing connectivity of restricted areas suchas Critical Infrastructures (CIs) raises major security concernsfor Supervisory Control And Data Acquisition (SCADA) systems,which are deployed to monitor their operation. Given the impor-tance of an early anomaly detection, Intrusion Detection Systems(IDSs) are introduced in SCADA systems to detect malicious ac-tivities as early as possible. Agents or probes form the cornerstoneof any IDS by capturing network packets and extracting relevantinformation. However, IDSs are facing unprecedented challengesdue to the escalation in the number, scale and diversity of attacks.Software-Defined Network (SDN) then comes into play and canprovide the required flexibility and scalability. Building on that,we introduce Traffic Agent Controllers (TACs) that monitor SDN-enabled switches via OpenFlow. By using lightweight statisticalmetrics such as Kullback-Leibler Divergence (KLD), we are ableto detect the slightest anomalies, such as stealth port scans, evenin the presence of background traffic. The obtained metrics canalso be used to locate the anomalies with precision over 90%inside a hierarchical network topology. [less ▲]

Duplicate Suppression for Efficient Floating Car Data Collection in Heterogeneous LTE-DSRC Vehicular Networks

in Computer Communications (2018), 123

Collecting data from a large number of agents scattered over a region of interest is becoming an increasingly appealing paradigm to feed big data archives that lay the ground for a vast array of ... [more ▼]

Collecting data from a large number of agents scattered over a region of interest is becoming an increasingly appealing paradigm to feed big data archives that lay the ground for a vast array of applications. Vehicular Floating Car Data (FCD) collection is a major representative of this paradigm. Massive data collection from floating vehicles is the key to Intelligent Transportation Systems. We address the design and performance evaluation of a data collection protocol for the use case of periodic data collection. We target robustness, optimizing the amount of data and the value of the collection period, keeping in mind the goals of autonomous node operation and minimal coordination effort. From a system point of view, we believe that best solutions should jointly exploit the Long Term Evolution (LTE) cellular access network and the Dedicated Short-Range Communication (DSRC) based Vehicular Ad Hoc Network (VANET). Through a detailed comparative analysis, we show that such a hybrid approach offers superior performance, especially as for offloading the cellular radio access. A lightweight signaling procedure is designed, based on the DSRC VANET, which is able to avoid most of the duplicated data records, even if a distributed operation approach is pursued. The impact of the proposed protocol on the VANET load is evaluated and proved to be quite small, so that it does not interfere with other VANET-specific messages. [less ▲]

A Model for the Optimization of Beacon Message Age-of-Information in a VANET

in 29th International Teletraffic Congress (ITC 29) (2017, September)

Beaconing is a basic communication process taking place in Vehicular Ad Hoc Networks (VANETs) to achieve cooperative awareness among vehicles on the road. It is actually a paradigm of information ... [more ▼]

Beaconing is a basic communication process taking place in Vehicular Ad Hoc Networks (VANETs) to achieve cooperative awareness among vehicles on the road. It is actually a paradigm of information spreading among peer-agents, where each node of a networks sends periodically broadcast messages containing information collected by the node itself. A trade-off arises between the update frequency of the broadcast information and the congestion induced in the wireless shared channel used to send the messages, which is based on the IEEE 802.11p standard in case of a VANET. For periodic updates, the primary metric is the Age-of-Information (AoI), i.e., the age of the latest update received by neighboring nodes. We define an analytical model to evaluate the AoI of a VANET, given the connectivity graph of the vehicles. Analytical results are compared to simulation to assess the accuracy of the model. The model provides a handy tool to optimize the AoI trade-off. [less ▲]

Pick the Right Guy: CQI-Based LTE Forwarder Selection in VANETs

in 8th IEEE Vehicular Networking Conference (VNC 2016) (2016, December)

Periodical collection of data from vehicles inside a target area is of interest for many applications in the context of Intelligent Transportation Systems (ITS). Long Term Evolution (LTE) has been ... [more ▼]

Periodical collection of data from vehicles inside a target area is of interest for many applications in the context of Intelligent Transportation Systems (ITS). Long Term Evolution (LTE) has been identified as a good candidate technology for supporting such type of applications - particularly for the non-safety domain. However, a high number of vehicles intermittently reporting their information via LTE can introduce a very high load on the LTE access network. In this context, the use of heterogeneous networking technologies can yield significant offloading of LTE - here, WLAN and Dedicated Short-Range Communication (DSRC) technology can support local data aggregation. In this paper, we propose an on-the-fly distributed clustering algorithm that uses both LTE and DSRC networks in the forwarder selection process. Our results clearly indicate that it is crucial to consider parameters drawn from both networking platforms for selecting the right forwarders. In particular, we show for the first time that relying on the Channel Quality Indicator (CQI) has a substantial impact. We demonstrate that our solution is able to significantly reduce the LTE channel utilization with respect to other state of the art approaches. [less ▲]

An integrated VANET-based data dissemination and collection protocol for complex urban scenarios

in Ad Hoc Networks (2016), 52(Supplement C), 28-38

Data dissemination and data collection to/from vehicles traveling on city roads are key features to fully enable the advent of Intelligent Transport Systems and Autonomous vehicles. Both Road Side Units ... [more ▼]

Data dissemination and data collection to/from vehicles traveling on city roads are key features to fully enable the advent of Intelligent Transport Systems and Autonomous vehicles. Both Road Side Units and On Board Units need to disseminate different kind of data to vehicles or to collect data sensed by the vehicles themselves and transfer them to road monitoring and control centers. In this work we propose a protocol, named DISCOVER, that disseminates and collects the data of interest in a quite large city area efficiently and timely by using a single network structure, i.e., a multi-hop backbone made up only of vehicles nodes. DISCOVER is distributed and adaptive to the different traffic conditions, i.e., to the different levels of vehicular traffic density. Several numerical results show that it attains very good performance in different type of city maps (New York, Paris, Madrid and Rome) when compared with baseline approaches as well as when compared with a theoretical bound. [less ▲]

DISCOVER: A Unified Protocol for Data Dissemination and Collection in VANETs

in Proceedings of the 12th ACM Symposium on Performance Evaluation of Wireless Ad Hoc, Sensor, \&\#38; Ubiquitous Networks (2015, November)

Message dissemination and data collection from vehicles are two key enablers of Intelligent Transportation System services that can be offered by a Vehicular Ad-Hoc Network (VANET) technology. In this ... [more ▼]

Message dissemination and data collection from vehicles are two key enablers of Intelligent Transportation System services that can be offered by a Vehicular Ad-Hoc Network (VANET) technology. In this work we propose a fully distributed protocol for dissemination of query and collection of reply messages carrying information gathered from vehicles moving in a given target area, in an urban scenario. The key idea is to use the dissemination phase (forward wave) to create a network of relay nodes that are in charge of delivering reply messages back to the originating point (reverse wave). The proposed protocol is evaluated with reference to two real urban environments. Main parameters are dimensioned and an insight in the protocol working is given. [less ▲]