Autonomous Vehicles - KPIT

information flow and maintaining the privacy
of users. Hence, autonomous vehicles share
a set of following challenges while considering
their communications strategy.
The information flow such as forward warning
or obstacles or deceleration should reach the
successor car within the stipulated time,
otherwise it is going to be catastrophic. Thus,
self-driving technology has stringent delay
requirements and thus the protocol should
support the same.
The information such as traffic management
systems, GPS based traffic movement or
weather forecast information should follow to
the vehicle to have smooth driving
experience. Nevertheless, the information
from various sensors and infrastructure needs
to be available for processing such as either
co-operative cruise control, GPS based traffic
movement or infotainment needs. Thus, it
requires the high volume data transfer within
the limited processing and response time and
it requires having high data rate
communication.
It is important to notice that the accuracy and
correctness of data is vital to have safer
driving. Above all, secure and encrypted data
communication is needed to avoid any
unintended threats from external sources.
The solution for these communication
challenges is to have the involvement of
various technologies such as internet,
security, encryption, wireless and radio
technologies etc. Thus, Vehicle Ad-hoc
Networks (VANETS) is arrived to overcome
these communication challenges. The multihop
ad-hoc communication standards are not
specific to any certain application area and
based on current available wireless LAN radio
technology with suitable adaptations.
IV. Vehicle Ad-hoc Networks
The popular architecture of VANETS (Vehicle
Ad-hoc Networks) includes Wireless Access
in Vehicular (WAVE) by IEEE, Continuous Air
Interface for Long to Medium Range (CALM)
by ISO and Car-to-Car Network (C2CNet) by
C2C consortium.
Further, in this article we shall discuss salient
features of these architectures.
A. WAVE (Wireless Access in Vehicular)
A complete protocol stack of 1609 protocol
WAVE Station Management
family by IEEE named it as Wireless Access in
Vehicular (WAVE) and it supports dedicated
short-range communication (DSRC) too. This
works on 5.9GHZ frequency band. WAVE
enlists two modes of communication
lSafety applications (NON IP)
lNon Safety applications based on IPV6
IEEE802.11p protocol based Microcontroller
Abstraction layer (MCAL) uses WAVE
architecture and IEEE802.11p is the approved
amendment of IEEE802.11 to have wireless
access in vehicular environments.
IEEE802.11p task force formed in Nov. 2004
and the final amendment was available by
2010. This protocol consists of internet
technologies and IEEE802 (IEE802.11p,
IEEE802.11 and IEEE802.2).These protocols
serve as access point to the external world.
Layer Management (1609.5)
Security (1609.2)
Applications (1609.1)
Channel Coordination (16094)
Figure 7: WAVE Architecture [3, 5]
Facilities (1609.6)
Transport & Network Layer
(1609.3)
UDP
Ipv6
TCP
WAVE architecture is based on complete
standard of IEEE1609 and there are six sub
standards as IEEE1609.1 to IEEE1609.6 as
part of IEEE1609. Each of those substandard
describes as [3]:
•IEEE1609.1 for the management activities to
achieve the proper operation
•IEEE 1609.2 for the communication security
•IEEE 1609.3 for transport and network layer
handling of traffic safety related applications –
WSMP (Wave Short Messages Protocol).
•IEEE 1609.4 defines the coordination
between the multiple channels of spectrum.
•IEEE 1609.5 deals with Layer management
•IEEE 1609.6 offers application facility layer
situated between transport and application
layer.
As IEEE WAVE, architecture restricts the
MicroController Abstraction Layer (MCAL)
with this only option – IEEE802.11p and it
restricted the research or usage of alternative
WSMP
Logical Link Sub-Layer (802.2)
MAC Layer Sub-Layer (802.11)
Physical Layer (802.1p)
42 TechTalk@KPIT, Volume 6, Issue 4, 2013