30-01-2013, 04:45 PM
Multi-agent System Based Critical Information Gathering and Dissemination in VANETs
1Multi-agent System.pdf (Size: 144.62 KB / Downloads: 22)
ABSTRACT
Today’s vehicles have the capability of sensing, computing and communicating capabilities.
Different components in the vehicle constantly exchange the available information with other
vehicles on the road and cooperate for the purpose of ensuring safety and comfort, known as
Vehicular Ad hoc Network (VANET). VANETs are a specific type of Mobile Ad hoc
Networks (MANETs) that are currently attracting the attention of researchers around the world.
With pervasiveness of mobile computing technology and wireless communications, VANETs
could be a key networking technology of the future vehicle communications. In VANETs,
critical informations like navigation, cooperative collision avoidance, lane-changing, speed
limit, accident, obstacle or road condition warnings etc. plays a significant role for safetyrelated
applications. Such kind of critical information gathering is challenging, because of their
delay-critical nature. In order to gather critical informations efficiently dynamic time sensitive
algorithms are necessary. In this paper we have proposed a multi agent based algorithm that
considers the critical information gathering and dissemination, depending on the information
relevance and importance. The main contribution of our work lies in the efficiency of the
algorithm in gathering and disseminating the information with minimum time.
INTRODUCTION
Vehicular ad hoc networks (VANETs) are expected to support a large spectrum of mobile
distributed applications ranging from traffic alert dissemination and dynamic route planning to
context-aware advertisement and file sharing. Considering the large number of nodes
participating in these networks and their high mobility, debates still exist about the feasibility
of applications using end-to-end multi-hop communication. The main concern is whether the
performance of VANET routing protocols can satisfy the throughput and delay requirements of
such applications.
VANETs are special case of MANETs. The key differences as compared to MANET
environment are following.
· Components building the network are vehicles.
· Restricted mobility constraints.
· Time-varying vehicle traffic density.
· Most of the vehicles provide sufficient computational and power resources, thus
eliminating the need for introducing complicated energy aware algorithms.
· Vehicles will not be affected by the addition of extra weight for antennas and additional
hardware.
Most of the protocols designed for MANETs may not be directly applied to VANETs,
since they may not take into account high mobility and restricted mobility constraints
(roadways). Some parameters which have to be mainly concentrated in VANETs for protocol
design are extremely high mobility, restricted movements, fast topology changes and time
varying vehicle traffic density.
RELATED WORKS
The work discussed in [1] [2] depicts A Vehicular Ad-Hoc Network, or VANET, as a form of
Mobile ad-hoc network, to provide communications among nearby vehicles and between
vehicles and nearby fixed equipment, usually described as roadside equipment. A peer to peer
vehicle communication and safety applications, Vehicular Communication Systems are an
emerging type of networks in which vehicles and roadside units are the communicating nodes;
providing each other with information, such as safety warnings and traffic information are
discussed in [3] [4] [5] [6]. The work given in [7] presents an autonomous, self-organizing and
decentralized configuration and management system for a group of base stations in wireless
networks. The individual base stations aggregate and share network information. A distributed
algorithm computes a local configuration at each base station based on the shared information.
The work given in [8] considers an imaginary road divided into fixed length segments and
studies the influence of vehicle density, relative velocity, and number of lanes on node
connectivity
The work given in [9] presents a Mobile Ad-Hoc Network (MANET) hosts
communicate with each other without any centralized control. Due to various constraints like
scarcity of resources, excessive routing overhead etc, the cluster routing protocol in MANETs
becomes less reliable. The work given in [10] presents the concept of mobile agents to gather
information and perform tasks on behalf of a user, migrating to the source of information and
reducing network bandwidth of messages required to process data. An agent is seen as a
migrating program that has both a static part (code) and a dynamic state (data). Each host
execution can be said to add new information progressively to the data state of an agent.
The work in [11] presents initial work in mobile agents such as identified two modes of
information gathering: stateless and stateful. In a stateless approach, agents can intermittently
or at every hop send information acquired back home to the originator. In a stateful mode, the
agent embodies in its data state the results of each host execution and carries with it a growing
collection of information to each subsequent host in its itinerary. The work in [12] states that
information collection is an important issue for vehicular ad-hoc networks (VANETs).
Congestion notification applications are built to warn drivers of traffic slowdowns far enough
in advance that the drivers may take alternate routes. This paper presents a new technique for
aggregating vehicles data without losing accuracy. Vehicles build a local view based on speed
and position reports from neighboring vehicles. Vehicles use received aggregated frames to
extend their views even farther.
Simulation model
Simulated VANET for an area of A X B kms. L numbers of base stations are considered for the
simulation. The communication coverage range for each base station is Trange. N number
vehicles are considered for the network. In order to simulate the mobility of vehicles in this
network, we considered one lane and vehicles moving one direction with m Kms/hour of
mobility. Each vehicle is assigned a fixed mobility and by making it to keep a safety distance
of R meters from the preceding and succeeding vehicle.
CONCLUSIONS
The proposed multi agent based information gathering and dissemination scheme identified
some of the important issues for information gathering, dissemination and proposed a set of
novel and effective architecture to resolve them by using agent technology. All the proposed
schemes have been simulated in various network scenarios for testing their performance and
operation effectiveness. A further refinement of the network architecture, facilitated by the use
of agent technology, is this. Instead of fixed base stations situated at strategic points along the
highway, each defining a cluster and vehicles belong to a cluster according to proximity to a
base station.