Roberto Baldessari

Vehicular wireless short-range communication for improving intersection safety

Vehicle-to-infrastructure and vehicle-to-vehicle communication has recently garnered considerable attention from both academia and industry because it holds the potential to improve road safety and to reduce road accidents. For this reason, V2X communication has been considered a key technology of the future Intelligent Transportation Systems. Use cases for V2X communication for enhancing intersection safety are appealing because intersections are the most complex and dangerous driving environments. This article reviews major related work and presents a communication architecture for intersection safety that supports these use cases. Our communication architecture respects the salient traits of V2X communication and fits into the overall V2X communication architecture. We perform various simulations to quantify the load of V2X communication at intersections and report the findings of our simulation study.

Design principles of an operator-owned highly distributed content delivery network

Mobile network operators are experiencing a tremendous increase in data traffic due to the growing popularity of bandwidth-intensive video services. This challenge can be faced either by boosting the capacity of the network infrastructure, or by means of offloading traffic from the backhaul and core network and serving contents from distributed cache servers close to the users. Network operators can extend the coverage of traditional CDNs by making usage of caching locations much closer to the users than traditional CDNs. Additionally, network operators can optimize the caching and delivery of contents by exploiting the complete knowledge of their network for designing a cost-effective infrastructure able to achieve both improved user satisfaction and cost savings. This article provides thoroughly justified design principles for a highly distributed operator-owned CDN while focusing on four key aspects: the optimal location of cache servers, mechanisms for request routing, content replica placement, and content outsourcing and retrieval.

Performance Evaluation of Beacon Congestion Control Algorithms for VANETs

Beacon and event-driven warning messages are two important messages that are used by many Intelligent Transportation Systems (ITS) applications for improving road safety and traffic efficiency. Beacon messages are regularly broadcast by each vehicle to notify other vehicles of its presence and its status. Event-driven warning messages are emitted when a vehicle or the road infrastructure discerns a critical situation. When congestion occurs, it is necessary to reduce the beacon load to keep a certain amount of the available bandwidth for the event-driven messages because they carry time- critical information of high importance. This paper considers three beacon congestion control algorithms that control the beacon load below a certain threshold by adjusting the transmit rate and/or transmit power for the beacon messages. We perform a large set of simulations to evaluate these algorithms. Our simulation results reveal promising results for these algorithms.

Congestion control for safety messages in VANETs: Concepts and framework

Congestion control in packet data networks has been extensively studied. However, most algorithms are not directly applicable to safety messages in Vehicular Ad Hoc Networks (VANETs), which have stringent requirements on delay, reliability and dissemination area. Although certain algorithms have been investigated, there is still a lack of understanding on the related concepts, and there is no systematic analysis on different mechanisms in the overall context so far. This paper explores related concepts and their dependencies, makes a systematic analyse and presents a framework on congestion control for safety messages in VANETs.

Distributed rate control algorithm for VANETs (DRCV)

This paper presents Distributed Rate Control for VANETs (DRCV), a distributed light-weight congestion control algorithm tailored for safety messages. DRCV monitors and estimates channel load and controls the packet rate of outgoing periodic packets. A new approach called Fast Drop is adopted to promptly drop the rate of periodic packets when event-driven safety packets are detected. Simulations show the effectiveness of DRCV in increasing packet reception probabilities and achieving efficient channel usage.

V2X Communication and Intersection Safety

Vehicle-to-vehicle and vehicle-to-infrastructure communication (V2X communication) has great potential to increase road and passenger safety, and has been considered an important part of future Intelligent Transportation Systems (ITS). Several R&D projects around the world have been investigating various aspects of V2X communication. Some of these projects focus on specific issues of V2X communication for intersection safety (communication-based intersection safety) because intersections are the most complex driving environments where injury and fatal accidents occur frequently. In this paper, we discuss the technical details of V2X communication and discuss how it can be used to improve intersection safety.