How to Start Heterogeneous Networks Projects Using NS2

To start a Heterogeneous Network (HetNet) project using Network Simulator 2 (NS2), we will need to replicate a network environment including several kinds of nodes, interaction technologies, and protocols. HetNets normally combine diverse kinds of technologies like WiFi, cellular (LTE/5G), Zigbee, and Ethernet for improving the performance and connectivity. Following is a stepwise strategy to start and simulate the HetNet projects using NS2.

Steps to Start HetNet Projects in NS2

1. Set Up NS2 for Heterogeneous Networks

1. Install NS2:
   • We should download and install NS2 on the machine.
   • Make sure that we install essential patches for replication of heterogeneous network.
2. Extend NS2 for HetNet Features:
   • Make use of patches or integrate the custom modules to combine several technologies such as:
     • WiFi: It is directly supported for NS2.
     • Cellular Networks: It needs extensions such as NIST add-ons or network custom components.
     • Zigbee/IoT Protocols: Probably requires custom execution.
3. Verify Installation:
   • We execute a sample scripts for making sure that NS2 properly functions for both wired and wireless scenarios.

2. Understand Heterogeneous Network Requirements

• Components:
  • Cellular Base Stations (BSs), Zigbee nodes, routers, WiFi Access Points (APs), and so on.
• Communication:
  • Describe the interaction types like WiFi-to-WiFi, Cellular-to-WiFi, or WiFi-to-Zigbee.
• Mobility:
  • Make use of mobility models to travel among various networks for nodes.
• Performance Metrics:
  • Estimate the performance parameters such as handover latency, throughput, packet loss, energy efficiency, and so on.

3. Define the HetNet Topology

Make a network topology including several network types to utilise Tcl script.

Example: Basic Heterogeneous Network

# Create a simulator instance

set ns [new Simulator]

# Trace and NAM files

set tracefile [open hetnet.tr w]

set namfile [open hetnet.nam w]

$ns trace-all $tracefile

$ns namtrace-all $namfile

# Define nodes

set wifiAP [$ns node]

set lteBS [$ns node]

set zigbeeNode [$ns node]

set mobileNode [$ns node]

# Configure wireless channels

$ns add-wireless-channel $wifiAP 2.4GHz 100m

$ns add-wireless-channel $lteBS 1.8GHz 300m

# Mobility configuration for mobileNode

$mobileNode set X_ 0

$mobileNode set Y_ 0

$mobileNode set Z_ 0

$ns at 1.0 “$mobileNode setdest 200 200 10”

# Connections

$ns duplex-link $wifiAP $lteBS 1Gbps 10ms DropTail

$ns add-wireless-connection $mobileNode $wifiAP

$ns add-wireless-connection $mobileNode $lteBS

$ns add-wireless-connection $mobileNode $zigbeeNode

# Application traffic

set udp [new Agent/UDP]

$ns attach-agent $mobileNode $udp

set null [new Agent/Null]

$ns attach-agent $wifiAP $null

$ns connect $udp $null

set cbr [new Application/Traffic/CBR]

$cbr set packetSize_ 512

$cbr set interval_ 0.1

$cbr attach-agent $udp

# End simulation

$ns at 10.0 “finish”

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam hetnet.nam &

exit 0

}

# Run simulation

$ns run

4. Implement Protocols

1. WiFi Configuration:
   • NS2 environment supports IEEE 802.11 directly.
2. Cellular Configuration:
   • We can utilise the extensions such as NIST add-ons or custom components for LTE/5G.
3. Routing Protocols:
   • For ad-hoc and hybrid scenarios, we need to utilise routing protocols such as AODV, DSDV, or DSR.
   • Instance:

$ns node-config -adhocRouting AODV

1. Handover Mechanism:
   • We will want to execute the logic for vertical handovers among the technologies like WiFi and LTE/5G.

Example Handover Logic:

proc handover {node fromNet toNet} {

global ns

set strength [$node get-signal-strength $fromNet]

if {$strength < -80} {

$ns disconnect $node $fromNet

$ns connect $node $toNet

}

}

5. Simulate Mobility

Replicate the movement of nodes among various network types to utilise the mobility models:

• Random Waypoint Mobility:
  • Make random movements within the simulation zone.
• Predefined Paths:
  • Specify the destinations at particular times for nodes.

Example Mobility Configuration:

$mobileNode setdest 300 400 15

6. Simulate Traffic

Make application-level traffic to experiment the interaction within the HetNet.

Example Traffic:

# UDP traffic from mobileNode to WiFi AP

set udp [new Agent/UDP]

$ns attach-agent $mobileNode $udp

set sink [new Agent/Null]

$ns attach-agent $wifiAP $sink

$ns connect $udp $sink

set cbr [new Application/Traffic/CBR]

$cbr set packetSize_ 256

$cbr set interval_ 0.1

$cbr attach-agent $udp

$ns at 0.5 “$cbr start”

7. Run the Simulation

1. We want to store the script in hetnet.tcl.
2. Execute the simulation script:

ns hetnet.tcl

1. Go to NAM for envisioning:

nam hetnet.nam

8. Analyze Results

• Trace File Analysis:
  • Examine the trace file as hetnet.tr for computing the performance indicators.
• Metrics to Evaluate:
  • Throughput: Compute the data delivery rate.
  • Packet Loss: Detect the packets that are dropped in the course of interaction.
  • Handover Latency: During transitions, we can measure the delays.

Example AWK Script for Throughput:

awk ‘{

if ($1 == “r” && $4 == “udp”) {

sum += $6

}

} END {

print “Throughput:”, sum / 1000, “kbps”

}’ hetnet.tr

9. Extend the Project

• QoS-Aware HetNet:
  • Execute the QoS strategies give precedence to traffic according to the type.
• Energy Efficiency:
  • Mimic power-efficient interaction within IoT scenarios.
• 5G Integration:
  • Integrate the components for replicating HetNet including 5G.
• Security:
  • Execute the encryption or verification for secure data transfer.

We have developed an extensive simulation for Heterogeneous Networks Projects using NS2 environment, and we can ready to provide detailed insights on this topic for further clarity if required.