How to Implement D2D Communication in ns2

To implement the Device-to-Device (D2D) communication is a communication technology in which devices interact directly with each other without depending on a centralized infrastructure such as a base station or access point. This communication is specifically useful in setups such as traffic offloading, public safety, proximity-based services in cellular networks. To execute the D2D communication within ns2 (Network Simulator 2) that has includes configuring nodes to communicate directly with each other through a wireless channel, without routing over a centralized node such as a router or base station.

Step-by-Step Implementations:

Step 1: Conceptualize the D2D Communication Simulation

In a D2D communication set-up:

  1. Device Nodes: It denote the devices that shall communicate directly with each other.
  2. Direct Communication Link: The wireless link among the devices that will permits for direct data exchange without intermediate nodes.
  3. Data Traffic: To emulate the interchange of data among the devices through this direct link.

Step 2: Create the Tcl Script

The following is an instance Tcl script that mimics a simple D2D communication situation in the simulation tool ns2, where two devices communicate directly with each other.

Example Tcl Script for Simulating D2D Communication in ns2

# Create a simulator object

set ns [new Simulator]

# Define the topography object (for a small area representing the proximity of devices)

set topo [new Topography]

$topo load_flatgrid 500 500  # 500m x 500m area

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

create-god 2  # Number of nodes (2 devices)

# Configure the nodes for direct communication

$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 \

-channelType Channel/WirelessChannel \

-topoInstance $topo \

-agentTrace ON \

-routerTrace ON \

-macTrace ON \

-movementTrace ON

# Open trace and NAM files for recording the simulation

set tracefile [open d2d_comm_out.tr w]

$ns trace-all $tracefile

set namfile [open d2d_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 d2d_comm_out.nam &

exit 0

}

# Create device nodes (D2D communication)

set device1 [$ns node]

set device2 [$ns node]

# Set initial positions for the devices (within direct communication range)

$device1 set X_ 100.0

$device1 set Y_ 250.0

$device1 set Z_ 0.0

$device2 set X_ 400.0

$device2 set Y_ 250.0

$device2 set Z_ 0.0

# Define traffic from device1 to device2 (simulating D2D data transmission)

set tcp [new Agent/TCP]

$ns attach-agent $device1 $tcp

set sink [new Agent/TCPSink]

$ns attach-agent $device2 $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

We save the script with a .tcl extension, for instance, d2d_comm_simulation.tcl then we can run the script using the below command in the terminal:

ns d2d_comm_simulation.tcl

Step 4: Visualize the Simulation

We need to visualize the simulation, open the created NAM file using:

nam d2d_comm_out.nam

Script Explanation

  • Device Nodes: The device nodes like device1 and device2 are signify two devices that communicate directly with each other in a D2D manner.
  • Direct Communication Link: The nodes are located in the direct communication range, permitting them to interchange data without intermediate nodes.
  • Traffic Generation: The TCP traffic is made from device1 to device2, mimicking a usual D2D communication setup.

Customization

  • Multiple Devices: We insert more devices to emulate a more difficult D2D communication network, possibly containing several D2D pairs.
  • Mobility Models: To execute the mobility patterns to mimic the devices moving in and out of the communication range that is general within D2D communication scenarios.
  • Different Data Types: Test with various kinds of traffic such as CBR, VoIP to mimic several D2D communication use cases.
  • Error Models: Launch error models to mimic the real-world wireless channel circumstances, like fading, interference, or packet loss.
  • Power Control: To execute the power control mechanisms to mimic the effects of modifying transmission power within D2D communication.

Limitations

  • Simplified Approximation: This emulations are offers a basic model of D2D communication. It does not encapsulate all the nuances of real-world D2D systems, like frequency reuse, interference management, or dynamic power control.
  • No Physical Layer Simulation: This script does not mimic the physical layer features particular to D2D communication, like proximity-based propagation effects or high interference setups.
  • Limited D2D-Specific Features: The network simulator 2 is not exactly designed for D2D communication, thus the emulation is limited to simplified functionality and high-level abstractions.

In the conclusion, we clearly discussed about the implementation and emulation procedure with example and some informations for D2D Communication in the network simulator 2. Also we will elaborate further information regarding this topic in another manual. Find creative Device-to-Device (D2D) communication project ideas along with implementation results at ns2projects.com.