How to Implement Wireless Communication in ns2

To implement the wireless communication in ns2 (Network Simulator 2) has needs to configure the wireless network environment, setup the mobile nodes, and describe the wireless communication protocols. The given below are the procedure to implement the wireless communication in ns2.

Step-by-Step Implementation:

Step 1: Create the Tcl Script

Generate a new Tcl script file like wireless_communication.tcl and initiate by configure the simple simulation environment for wireless communication.

Example Tcl Script

# Create a simulator object

set ns [new Simulator]

# Define the topography object

set topo [new Topography]

$topo load_flatgrid 500 500

# Configure the node movement and communication range

create-god 10  # GOD: General Operations Director for wireless simulations

$ns node-config -adhocRouting AODV \

-llType LL \

-macType Mac/802_11 \

-ifqType Queue/DropTail/PriQueue \

-ifqLen 50 \

-antType Antenna/OmniAntenna \

-propType Propagation/TwoRayGround \

-phyType Phy/WirelessPhy \

-topoInstance $topo \

-agentTrace ON \

-routerTrace ON \

-macTrace ON \

-movementTrace ON

# Open trace and NAM files for output

set tracefile [open wireless_out.tr w]

$ns trace-all $tracefile

set namfile [open wireless_out.nam w]

$ns namtrace-all-wireless $namfile 500 500

# Define a finish procedure to close files and end the simulation

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam wireless_out.nam &

exit 0

}

# Create wireless nodes

set n0 [$ns node]

set n1 [$ns node]

set n2 [$ns node]

set n3 [$ns node]

set n4 [$ns node]

# Set initial positions of nodes

$ns at 0.0 “$n0 setdest 100 100 0”

$ns at 0.0 “$n1 setdest 200 200 0”

$ns at 0.0 “$n2 setdest 300 300 0”

$ns at 0.0 “$n3 setdest 400 400 0”

$ns at 0.0 “$n4 setdest 250 250 0”

# Define traffic flows

# TCP Traffic from n0 to n3

set tcp0 [new Agent/TCP]

$ns attach-agent $n0 $tcp0

set sink0 [new Agent/TCPSink]

$ns attach-agent $n3 $sink0

$ns connect $tcp0 $sink0

set ftp0 [new Application/FTP]

$ftp0 attach-agent $tcp0

$ftp0 start

# UDP Traffic from n1 to n4

set udp1 [new Agent/UDP]

$ns attach-agent $n1 $udp1

set null1 [new Agent/Null]

$ns attach-agent $n4 $null1

$ns connect $udp1 $null1

set cbr1 [new Application/Traffic/CBR]

$cbr1 attach-agent $udp1

$cbr1 set packetSize_ 500

$cbr1 set rate_ 1Mb

$cbr1 start 1.0

# Schedule the simulation end time

$ns at 20.0 “finish”

# Run the simulation

$ns run

Step 2: Run the Tcl Script

Once writing the script, save it with a .tcl extension like wireless_communication.tcl. To execute the script, open a terminal and run the following command:

ns wireless_communication.tcl

This command will produce an output trace file (wireless_out.tr) and a NAM file (wireless_out.nam). we need to visualize the simulation using NAM.

Step 3: Visualize the Wireless Network

To visualize the wireless communication, open the NAM file with the following command:

nam wireless_out.nam

This will expose the NAM graphical user interface in which we can track the movement of nodes and the wireless communication among them.

Script Explanation

  • Simulator Object: $ns [new Simulator] generate an instance of the simulator.
  • Topography: set topo [new Topography] that describes the simulation area, which is a 500×500 grid.
  • Node Configuration: $ns node-config sets up numerous wireless metrics such as routing protocol (AODV), MAC layer (802.11), and antenna type (OmniAntenna).
  • Nodes: Nodes (n0, n1, etc.) denotes wireless devices and their initial positions are set using setdest.
  • Traffic: TCP and UDP traffic sources are generated to mimic the interaction among the nodes. TCP is used from n0 to n3 and UDP from n1 to n4.
  • Finish Procedure: The finish procedure is named at the end of the simulation to close trace files and open the NAM file for visualization.

Customization

We need modify the script to:

  • Change Routing Protocol: Swap AODV with other protocols such as DSDV, DSR, etc.
  • Modify Node Movements: Use various setdest commands to emulate the mobility.
  • Adjust Traffic: Maximize or minimize the number of traffic sources or vary their metrics such as packet size and rate.
  • Vary Topography: vary the dimensions of the simulation area by adapting the load_flatgrid.

Advanced Features

  • Mobility Models: We need to execute various mobility models like Random Waypoint by setting dynamic destinations and speeds for nodes.
  • Interference Models: Adapts the propagation model to mimic numerous kinds of wireless interference.
  • Network Scalability: Maximize the number of nodes and track the effects on network performance.

In the end of this page, we deliver the valuable details to help you to get started with a basic wireless communication simulation in OMNeT++ tool. Furthermore we will explain the details about the wireless communication.

Wireless Communication ideas  and topics are framed by us for scholars if you want to get more project guidance and implementation support look no one other then ns2projects.com