Information Technology Reference
In-Depth Information
Figure 14.5
Hybrid architecture of vehicle navigation systems.
shows the hybrid architecture. With the use of V2V communication links,
some vehicles that are beyond the transmission range of wireless BSs can
transmit data to and from BSs using V2V links. Therefore, the deployment
density of BSs can be greatly reduced. On the other hand, with the use of
BSs, the length of the multi-hop relay for remote vehicles can be reduced too,
thereby increasing the reliability of the V2V links.
14.2 Vehicle-to-Roadside-Based Vehicle Navigation Systems
In this section, we describe the main design principles of V2R-based vehi-
cle navigation systems on the basis of the methods proposed [9,14]. A V2R-
based navigation system needs an infrastructure to collect real-time traffic
information. The infrastructure includes a large number of roadside units
(or wireless sensors), BSs, and TICs. The roadside units use V2R links to
communicate with onboard units on passing vehicles to collect real-time
traffic information. Since the transmission range of roadside units is very
limited (e.g., 1000 meters for DSRC), the collected traffic information is first
delivered to BSs. The BSs then transmit the collected information to TIC at
a remote distance. We refer to the connections from BSs to TIC as backhaul
connections. Backhaul connections can be implemented by a variety of
wired or wireless technologies, such as frame relay, WiMax, wireless mesh
networks, and GPRS/3G. The TIC merges all collected real-time local traffic
information, generates wide-area traffic information and routing informa-
tion, and transmits the routing information to guided vehicles. The rout-
ing information may be broadcast to guided vehicles or unicast to guided
