How to Implement Optical Communication in ns2

To implement Optical Communication in Network Simulator 2 (ns2) has needs to make a custom technique while the ns2 was primarily intended for emulated an electromagnetic (EM) communication networks like wired and wireless networks. Optical communication has encompasses to the transmission of data using light that usually through optical fibers, free-space optical (FSO) systems, or visible light communication (VLC) systems. To estimate the optical communication in ns2, we will need to adapt the particular contexts, like channel modelling, propagation delays, and error models. The given below is the procedure to implement the optical communication in ns2:

Step-by-Step Implementation:

Step 1: Conceptualizing the Optical Communication Simulation

In a typical optical communication system:

  1. Optical Transmitter: Sends data in the form of light signals that can be denoted by a node in ns2.
  2. Optical Receiver: Receives the light signals and decodes the data, also signify by a node in ns2.
  3. Optical Channel: The medium through which light propagates, like an optical fiber or free space, that can be modelled as a link with the particular features (high bandwidth, low error rates, etc.).

Step 2: Create the Tcl Script

The given below is an example Tcl script that emulates simple optical communication system in which a transmitter sends data to a receiver over an optical link.

Example Tcl Script for Simulating Optical Communication in ns2

# Create a simulator object

set ns [new Simulator]

# Define the topography object (for a basic point-to-point link)

set topo [new Topography]

$topo load_flatgrid 500 500  # 500m x 500m area (for free-space optical or point-to-point fiber communication)

# Create the General Operations Director (GOD) for wireless simulations

create-god 2  # Number of nodes (1 transmitter + 1 receiver)

# Configure the nodes (simulating optical communication parameters)

$ns node-config -llType LL \

-macType Mac/802_11 \

-ifqType Queue/DropTail/PriQueue \

-ifqLen 50 \

-antType Antenna/OmniAntenna \

-propType Propagation/FreeSpace \

-phyType Phy/WirelessPhy \

-channelType Channel/WirelessChannel \

-topoInstance $topo \

-agentTrace ON \

-routerTrace ON \

-macTrace ON \

-movementTrace OFF

# Open trace and NAM files for recording the simulation

set tracefile [open optical_comm_out.tr w]

$ns trace-all $tracefile

set namfile [open optical_comm_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 optical_comm_out.nam &

exit 0

}

# Create transmitter and receiver nodes

set transmitter [$ns node]

set receiver [$ns node]

# Set initial positions for transmitter and receiver

$transmitter set X_ 100.0

$transmitter set Y_ 250.0

$transmitter set Z_ 0.0

$receiver set X_ 400.0

$receiver set Y_ 250.0

$receiver set Z_ 0.0

# Define the optical link (simulating high bandwidth, low error rate)

$ns duplex-link $transmitter $receiver 10Gb 0.1ms DropTail  # 10 Gbps link with 0.1ms delay

# Introduce an error model to simulate optical channel impairments

set loss_module [new ErrorModel]

$loss_module unit pkt

$loss_module set rate_ 0.001  # 0.1% packet loss rate (adjust for different optical channel conditions)

$ns lossmodel $loss_module $transmitter $receiver

# Define traffic from transmitter to receiver (simulating data transmission over optical link)

set tcp [new Agent/TCP]

$ns attach-agent $transmitter $tcp

set sink [new Agent/TCPSink]

$ns attach-agent $receiver $sink

$ns connect $tcp $sink

set ftp [new Application/FTP]

$ftp attach-agent $tcp

$ftp start

# Schedule the end of the simulation

$ns at 10.0 “finish”

# Run the simulation

$ns run

Step 3: Run the Tcl Script

Save the script with a .tcl extension, for example, optical_comm_simulation.tcl. after that execute the script using the following command in terminal:

ns optical_comm_simulation.tcl

Step 4: Visualize the Simulation

To visualize the simulation, open the generated NAM file using:

nam optical_comm_out.nam

Script Explanation

  • Transmitter and Receiver Nodes: These nodes denote the optical transmitter and receiver, respectively.
  • Optical Link Configuration: The duplex link between the transmitter and receiver is configured with a data rate of 10 Gbps and a very low delay (0.1ms) that emulates an optical communication link. The link delay and data rate can be modified according to the particular type of optical communication being modelled.
  • Error Model: An error model is established to emulate the impairments in optical communication, like attenuation, scattering, and other noise factors. The packet loss rate is set to 0.1% as an example.
  • Traffic Generation: TCP traffic is produced from the transmitter to the receiver to replicate the data transmission over the optical link.

Customization

  • Adjusting Link Parameters: Adjust the link data rate, delay, and error rate to reflect various optical communication scenarios, like long-haul optical fiber communication or free-space optical communication.
  • Multiple Transmitters and Receivers: Extend the network to contain the multiple transmitters and receivers to emulate a more complex optical network.
  • Advanced Error Models: Execute more sophisticated error models to emulate the different optical impairments such as chromatic dispersion, polarization mode dispersion, and non-linear effects.
  • Optical Routing Protocols: Incorporate optical-specific routing protocols if simulating a larger optical network with multiple nodes.

Limitations

  • Simplified Approximation: This simulation delivers a high-level abstraction of optical communication and doesn’t observes the detailed physical layer features such as wavelength division multiplexing (WDM) or particular optical modulation approaches.
  • No Physical Layer Simulation: The script does not replicate the actual light propagation, optical modulation, or demodulation processes that has in optical communication.
  • Limited Optical Communication Features: ns2 does not support directly that thorough the optical communication characteristics, so the simulation is limited to simple functionality and high-level abstractions.

From the demonstration we completely aggregate the information about the installation process and implementation procedure for optical communication that were deploy in the tool of ns2. More information regarding the optical communication will also be provided.

If you need more help, just reach out to us at ns2project.com. We’re here to help you with network analysis for your Optical Communication project.