Vehicular Networking

Project Objectives:
This project (started in Summer 2006) seeks to develop networking protocols for timely, reliable and trustworthy communication in automotive ad hoc networks. Automotive ad hoc networks are challenging due to high node mobility causing frequent network topology changes, low-latency interaction requirements, scenarios with very high node densities as well as privacy and security concerns. We meet these challenges by developing location-aware ad hoc network protocols, which address network nodes through their geographic position rather than conventional network addresses. We are also studying the performance of single-hop broadcast communications, adopted by cooperative collision warning (CCW) applications.

Technology Rationale:
Maturing ad hoc wireless communications and distributed computing technology enable novel distributed automotive sensing and control systems with compelling applications, such as preventing traffic accidents and improving traffic flow. Automotive vehicle accidents still account for approximately 40,000 fatalities in the US and are the leading cause of death for people aged 5-45 years. Accidents are also a primary contributor to congestion, which overall results in 5.7 billion person-hours of wasted travel time annually in the US (2002 estimate). Current technology seeks to address these challenges through in-vehicle sensing, control systems (e.g., electronic vehicle stability control) and road side infrastructure (e.g., dynamic traffic signs, ramp metering).

Significant additional potential can be realized by combining these systems through wireless communications into distributed sensing and control systems. Applications of such systems include cars on collision course warning each other and coordinating an evasive maneuver or cars can communicate their sensor readings to following vehicles to notify them of hazards (e.g., slippery road conditions) and congestion levels (see Figure). These compelling applications have recently led the US Federal Communications Commission (FCC) to approve radio spectrum for Dedicated Short Range Communications, a networking standard for inter-vehicle and vehicle to roadside communication. and innovative uses, from cordless phones and wireless LANs to meter readers and home entertainment products. These diverse services will need to coexist with the emergence of a wide variety of wireless devices, ranging from low bit rate sensors to high resolution full motion video cameras. The combination of increasing data rates and the proliferation of devices could easily lead to inefficiency in the use of unlicensed spectrum due to a combination of overuse and failure to develop mechanisms for efficient sharing of this resource.

Technical Approach:
Realizing this vision requires an interdisciplinary approach with communications research in location-aware and robust protocols. Location-aware protocols promise to address the challenges created by short-range radios in vehicles. Vehicles must reliable set up a connection and communicate information during the small time interval when the communication partner is in radio range. Communication is not always possible, thus vehicles must store information and form delay-tolerant networks. Since the identities of the vehicles in the local network are frequently changing, location becomes a key primitive for addressing and scoping the distribution of sensor information relevant to a local area. For example, if there is a traffic jam on a highway, warning messages need only be distributed to cars within a certain distance that are heading towards the congested area. As vehicles increasingly take action based on sensor data, the protocols must also meet security, privacy and robustness requirements. Received data requires validation, for example by corroborating it with data from other vehicles, to establish its accuracy because corrupted data may be injected by faulty sensors, or maliciously inserted by an adversary. Privacy can be increased by incorporating data anonymity techniques. These protocols will be evaluated on the outdoor testbed under construction as part of the ORBIT project.

In order to investigate the impact of interference and congestion, we are also studying the performance of single-hop broadcast communications, on the indoor ORBIT grid, in the presence of a large number of transmitters.

Results To Date and Future Work Plan:
A first-iteration design of the automotive outdoor testbed has been completed and we are deploying outdoor nodes. Funding for these projects has been secured from several industry partners. In addition the NSF funded ORBIT and Location Privacy projects contain vehicular components.

An ORBIT node, part of the automotive outdoor testbed.