EFFICIENT BROADCASTING WITH GUARANTEED COVERAGE

IN MOBILE ADHOC NETWORKS

By:Amit Kumar SinghAamir NasirAshish KumarChhotelal YadavUnder The Guidance Of

H.P .

What is Manet ?

• wireless ad hoc network

• arbitrary topology.

• routers are free to move randomly and organize themselves arbitrary.

What is ADHOC NETWORK ?

• Connection is established for the duration of one session and requires no base station.

• Search for target nodes that are out of range by flooding the network with broadcasts that are forwarded by each node.

• Routing protocols then provide stable connections even if nodes are moving around.

What is BROADCASTING ?

• fundamental operation for communication in adhoc networks

• Broadcast is the process of sending a message from one node to all other nodes in an ad hoc network.

• update of network information and route discovery as well as other operations.

Existing System

In existing system, the receivers are arranged in the form of mesh that faces problems such as,• Receiving duplicate packets from adjacent receivers (data redundancy).• delay in ACK is increased when redundant packets are sent to the receiver.

Blind flooding (BF)• Where each node forwards the packet once.• No ACK.• No non-forwarding node. • Re-Transmission may result in BROADCAST STORM problem. • Subset of nodes forward message.• Remaining nodes used to reduce the broadcast congestion but still fulfill the

broadcast coverage

Limitations of Existing System

• Exposed terminal problem• Hidden terminal problem• Blind flooding (BF)• Broadcast storm problem

o Redundant rebroadcastso Medium Contentiono Packet Collision

Proposed System

In the proposed system, The DOUBLE COVERAGE BROADCAST Algorithm is used to remove the drawbacks of existing system

The proposed DCB algorithm works as following: • When a sender broadcasts a packet, it selects a subset of 1-hop neighbors

as its forwarding nodes to forward the packet. • The selected forwarding nodes satisfy two requirements:

o they cover all the sender’s 2-hop neighbors; and o the sender’s 1-hop neighbors are covered by at least two forwarding

nodes.• Nodes out of one another’s transmission range need the support of

intermediate nodes. • Retransmissions of the forwarding nodes are received by the sender as the

ack of their reception of the packet

Advantages of proposed system

• Data redundancy is avoided, i.e. each node receives the packet once.

• If a node fails-node topology is rearranged so that child nodes of failed node receive the packets.

• The forwarding nodes are selected in such a way that they balance the average retransmission redundancy.

• The scheme avoids the broadcast storm problem.

• This scheme also avoids the ACK implosion problem: the retransmissions of forwarding nodes are also used as the ACKs to the sender so that no extra ACKs are needed.

• Each non-forwarding node is covered by at least two forwarding neighbors so that it can tolerate a single transmission error and increasing the chance to receive the broadcast packet successfully

Limitations of the Proposed System

• As the number of nodes increase in topology, the chances of proper working of project is reduced

• The project works properly only in case of one node failure.

• The number of forwarding and non-forwarding nodes is limited to a maximum of 2 so that only small topology can be selected.

Modules

• Create Nodes• Start Node

Module Details

• createnodes:• The createnodes Module consists of the GUI for

entering the information of each node and saving it in database. The information associated with a node is ,

• Source node• Parent node• Left child • Right child• No. Of forwarding nodes• No. Of non-forwarding nodes• Name of non-forwarding node

Flow Diagrams

Screen shots

Module Details

• Startnode:• The startnode class consists of methods which are used

to broadcast packets and send/receive acknowledgement. The select node method creates GUI to write message and has buttons to start, disconnect nodes, send packets etc..

• When the node is selected from combo box, the database is checked to see if the selected node already exists or not. If the node already exists, then a prompt is given to select other node. If the selected node is a new node, a window appears prompting for port number of node. When port no. is entered and ok button is clicked, the node details are saved in database.

Algorithms Used for Enhancement

• The Double-Covered Broadcast Algorithm

-Forwarding Node Set Selection Process - Double Coverage (FNSSP-DC)

System Specification

• Software specificationo Java1.4 or Moreo Swingso Windows 98 or Moreo MS-Access

• Hardware specification-Hard disk: 10 GB or More-RAM: 128MB or More-Processor: Pentium 3 or More

. Conclusions and Future Work

• The DCB provides full reliability for all forwarding nodes but not for non-forwarding nodes. In order to provide full reliability for all non-forwarding nodes, we can use the NACK mechanism such that a non-forwarding node will send a NACK message when the node notices a packet loss during the continuous broadcasting transmissions.

• Our future work is to investigate the strategies of applying the NACK mechanism and the effects when the NACK mechanism is applied.