A NEIGHBOR COVERAGE BASED PROBABILISTIC REBROADCAST FOR REDUCING ROUTING OVERHEAD IN

MOBILE AD-HOC NETWORK

ABHIRAM.S

ROLL NO :20181

MTECH COMM. ENGG

Add-Hoc Network

• It is a decentralized type of wireless network.

• It does not rely on a pre-existing infrastructure, such as routers in wired

networks or access points in wireless networks.

• The routing decisions are made by the node itself.

• Ad-hoc network can be broadly classified into MANET and VANET.

MANET

• mobile ad hoc network (MANET) is a self-routing network of mobile

devices connected wirelessly

• MANETs have many applications : such as

military communication,

in search and rescue operations,

in home and enterprise networks,

in entertainment,

and in sensor networks

ROUTING PROTOCOLS IN MANET

• There are number of routing protocols in manet such as AODV,DSDV,DSR

etc..

• The routing protocols in MANET is classified into four types

1) PROACTIVE ROUTING

2) REACTIVE ROUTING

3) HYBRID ROUTING

4) HIERARCHICAL ROUTING

REACTIVE ROUTING

• This protocol do not have any pre determined routing table, it is otherwise

called On Demand Routing Protocol

• Here node initiates a route discovery process throughout the network, only

when it wants to send packets to its destination.

• Route discovery is done by using flooding of route request packets

• Eg: AODV

BROADCASTING

• Broadcasting is the simplest way for route discovery

• Broadcasting protocols are classified into 4 types

1)Simple flooding

2)Probability based method

3)Area based method

4)Neighbor knowledge method

• Performance of

neighbor knowledge based method>area based method>probability based method

A NEIGHBOR COVERAGE BASED PROBABILISTIC REBROADCAST(NCPR)

• NCPR is used to reduce routing overhead in mobile ad-hoc network.

• Here we use two parameter to obtain ‘rebroadcast probability’; they are

connectivity factor and additional coverage ratio.

• Additional coverage ratio=No. of nodes covered in a single broadcast/Total

number of neighbors

• Connectivity Factor: It gives the relationship of network connectivity &

number of neighbors of a given node

PROTOCOL IMPLEMENTATION

• Proposed NCPR requires hello packets to obtain neighbor information.

• Here we use some technique to reduce the routing overhead of hello packets.

1) We don't use periodic hello mechanism. The hello messages are send by

nodes if and only if

time elapsed from last broadcasting packet> hello interval

2)in order to reduce the overhead of neighbor list in the RREQ packet, each

node monitor the variation in neighbor table and maintain a cache of neighbor

list

• We modify the RREQ header of AODV and a fixed field “num_neighbors”

and this field is followed by dynamic neighbor list.

• If neighbor table of ‘ni’ adds at least one neighbor ‘nj’; then node ‘ni’ set the

num_neighbor to the number of listed neighbors plus a +ve integer.

• If neighbor table of ‘ni’ deletes some neighbors then the node ‘ni’ set the

num_neighbors to a –ve integer, which is equal and opposite to number of

deleted nodes

• If neighbor table of ‘ni’ does not vary then num_neigbors set to zero & ‘ni’

does not need to list its neighbors.

• LIST OF FILES THAT NEED TO BE MODIFIED

• ~/ns-allinone-2.35/ns-2.35/common/packet.h

• ~/ns-allinone-2.35/ns-2.35/trace/cmu-trace.h

• ~/ns-allinone-2.35/ns-2.35/trace/cmu-trace.cc

• ~/ns-allinone-2.35/ns-2.35/tcl/lib/ns-packet.tcl

• ~/ns-allinone-2.35/ns-2.35/tcl/lib/ns-default.tcl 

• ~/ns-allinone-2.35/ns-2.35/tcl/lib/ns-lib.tcl

• ~/ns-allinone-2.35/ns-2.35/queue/priqueue.cc

SIMULATION TOOL AND PARAMETERS

• The simulation is done by using NETWORK SIMULATOR-2 (NS 2)

• The parameters of the scenario is given in the table shown below.

Parameter value

Simulator NSVersion 2.35Protocol studied NCPRNumber of nodes  30 and 50Simulation Time 60 secSimulation Area 2000x2000Traffic Type UDPData Payload Bytes/packetBandwidth 600kbps

SIMULATION RESULTS

FUTURE WORKS

• Constant bit rate (CBR) NCPR protocol can be changed to variable bit rate

(VBR), in order to get better

1)Throughput

2)end to end delay

3)packet delivery ratio

REFERENCES

• Performance Analysis of MANET Routing Protocols Using An Elegant Visual Simulation Tool

Nazmus Saquib1, Md. Sabbir Rahman Sakib, and Al-Sakib Khan Pathan2Department of Electrical and Electronic

Engineering, BRAC University Department of Computer Science and Engineering, BRAC University66 Mohakhali,

Dhaka 1212, Bangladesh{nsaquib, srsakib}@bracu.ac.bd, sakib.pathan@gmail.com

• Simulation and Evaluation of MANET Routing Protocols for Educational Purposes

Alexandros Kaponias, Anastasios Politis, and Constantinos Hilas, Department of Informatics and Communications

T.E.I. of Serres Serres, Greece pli1542@teiser.gr. anpol@teiser.gr, chilas@teiser.gr

• Performance analysis of AODV, DSR & TORA Routing Protocols

Anuj K. Gupta, Member, IACSIT, Dr. Harsh Sadawarti, Dr. Anil K. Verma

• A comprehensive overview about selected Ad-Hoc Networking Routing Protocols

Daniel Lang March 14, 2003

THANK YOU