Inter Vehicular Communication Systems
Our vision is focused on utilizing the intrinsic properties of vehicular
traffic, coupled with modern communication, computing and
information management technologies, in order to facilitate increased
safety and situational awareness on high-speed highways. We anticipate
an environment where traveling vehicles communicate among themselves,
forming rapidly changing ad hoc network topologies.
Several cars travel on a highway while communicating locally via an
ad hoc wireless network
Each car is equipped with a laptop or PDA equipped with a wireless LAN card
(e.g., 802.11) for local communication
and forms, around itself, a local area of communication.
Cars that are further away, although they may constitute part of a neighbor's
local area, are not part of that particular car's communication network.
All cars broadcast information omni-directionally and receive data from any
and every direction. There is no point-to-point communication link.
The purpose of the ad hoc network is to impart information, i.e., the car's
vital signs, to vehicles in close proximity and to receive the same data
from them. The information is processed locally to provide the driver
with a map indicating the status of each car in the
immediate vicinity, e.g., acceleration, turning signal status, braking, etc.
We are faced with a very dynamic environment composed of fast-moving vehicles,
which, from the communication perspective, translates into rapidly changing
network topologies. In addition, the data that is exchanged between the
vehicles is time sensitive.
Since the communication devices are mounted in vehicles, power supply is
practically unlimited thus making it possible to use fairly large antennas
and on-board GPS devices. Also, the data is really of interest only to a
small circle of neighboring vehicles.
Although the problem is simplified by the single-hop nature of the network
and the consequent lack of routing, it also raises some concerns,
primarily, the throughput of the system and the delays involved.
Since data is time-sensitive, and in many cases, urgent in nature
(e.g., speeding vehicle approaching in left lane), the system must be
robust and capable to support the traffic load and its time critical needs.
Tradeoffs to be investigated involve the type of data, its urgency and the
practical limits of the system before it degenerates into chaos and data
flow comes to a halt. More complex, multi-channel systems capable of coping
with the traffic load and its delay constraints, pose a different set of
problems associated with the speed with which vehicles can associate
themselves to the different channels and maintain an up-to-date
picture of their surroundings.