Vehicular Sensor Networks: General Aspects and Implementation Issues - Application and Multidisciplinary Aspects of Wireless Sensor Networks - page 205

10.2 VSNs Classifications

The numerous VSNs' types and specific implementations found in the literature
today can be broadly classified into two groups:

• Intra-vehicle VSNs (a “single vehicle” VSN used for giving diagnostics to the
driver)
• Inter-vehicle VSNs (used for sharing the sensor data with other vehicles or infra-
structure components)

Intra-vehicle VSNs are introduced for the purposes of monitoring, control, and
communication between components and subsystems inside a vehicle. They are
motivated by the increasing complexity, weight, and cost of the wiring harness in
addition to the versatility of the wireless networking, which opens room for novel
architectures and reprogrammable functionalities. In-vehicle connectivity in an
intra-vehicle VSN is usually enabled by wireless standards for ad hoc communica-
tions such as Bluetooth [ 10 ], ZigBee [ 11 ] and UWB [ 12 ].
Inter-vehicle VSNs, either V2I/I2V or V2V, are based on different DSRC
(Dedicated Short Range Communication) standards at physical and data link layer
[ 13 ]. They can either be fully distributed or centralized. In V2V communication, a
vehicle can communicate with its neighboring vehicles even in the absence of a
central entity (e.g., a Base Station). The concept of this direct communication is to
send vehicle safety messages one-to-one or one-to-many via a wireless connection.
Such messages are usually short in length and have very short lifetime in which
they must reach the destination. The inter-vehicle communication system is gaining
momentum lately contributing to the increase in safety and the more intelligent
traffic management on roads [ 14 ].
Both types of VSNs have their specifics stemming from the actual technology in
use and applications in focus. The intra-vehicle VSNs are limited in space (one
vehicle) and applications (vehicle diagnostics such as road conditions, tire pressure,
etc.) making them predictable and easier for implementation. As a result, there are
numerous proprietary solutions in this field [ 8 ]. On the other hand, the inter-vehicle
VSNs prove to be more challenging since they require many mechanisms for proper
operation of the sensor data sharing under vehicular conditions. Some of the basic
mechanisms needed for their comprehensive analysis are elaborated in the following
section.

10.3 VSNs Basic Mechanisms

This subsection elaborates the basic mechanisms needed to fully comprehend
some of the most prominent specifics of the VSNs. They comprise topology
formation , mobility , routing, and data dissemination . Further aspects can be
found in [ 8 ].