How to Implement Vertical Handover in ns2

To implement vertical handover in Network Simulator 2 (NS2) has needs to emulate the process of switching among numerous types of network interfaces like from Wi-Fi to cellular while maintaining an on-going connection. Vertical handover is vital in heterogeneous networks in which the mobile nodes can switch among diverse network types based on conditions such as signal strength, data rates, or user preferences. The below is the implementation procedure for vertical handover in NS2:

Step-by-Step Implementation:

  1. Understand Vertical Handover
  • Vertical Handover (VHO): This refers to the handover process between different types of networks (e.g., Wi-Fi to 4G/LTE or Wi-Fi to 5G).
  • Handover Criteria: The key parameters such as signal strength (RSSI), network congestion, data rate, user preferences, and battery power.
  1. Set up the NS2 Environment
  • Install NS2: Make sure that NS2 installed on the system and that are used to with simple Tcl scripting and NS2 structure.
  • Study NS2 Modules: Evaluation NS2’s mobility and routing modules, as these are usually includes in handover scenarios.
  1. Network Topology Design
  • Heterogeneous Networks: Model a network topology with nodes that associated to diverse types of networks like Wi-Fi and LTE. Each node should have multiple interfaces.
  • Mobility Model: Execute a mobility model in which a mobile node moves among the coverage areas of diverse networks.

Example Tcl Script for a Simple Heterogeneous Network:

set ns [new Simulator]

set tracefile [open “vho_trace.tr” w]

$ns trace-all $tracefile

# Create Mobile Node

set mobile_node [$ns node]

# Configure Wi-Fi interface

$mobile_node add-interface “Wi-Fi”

# Configure LTE interface

$mobile_node add-interface “LTE”

# Create Access Points for Wi-Fi and LTE

set wifi_ap [$ns node]

set lte_ap [$ns node]

# Create links between APs and the mobile node

$ns duplex-link $mobile_node $wifi_ap 10Mb 2ms DropTail

$ns duplex-link $mobile_node $lte_ap 10Mb 2ms DropTail

# Define the mobility pattern

$ns at 5.0 “$mobile_node setdest 100 200 10”

$ns at 10.0 “$mobile_node setdest 300 400 10”

# Run the simulation

$ns run

  1. Implement Handover Decision Algorithm
  • Decision Logic: Execute the logic that regulates when and how the handover should happen. This could be based on signal strength, bandwidth availability, or other criteria.
  • Triggering Handover: We can use events in NS2 to cause handover when the particular conditions are met.

Example Handover Logic (Simplified in Tcl):

proc check_handover {node} {

set signal_strength [node get-signal-strength]

if { $signal_strength < $threshold } {

puts “Triggering handover for node $node”

# Call handover function here

handover $node

}

}

proc handover {node} {

puts “Performing handover for node $node”

# Switch from Wi-Fi to LTE

$node switch-interface “LTE”

}

$ns at 8.0 “check_handover $mobile_node”

  1. Customizing and Extending NS2
  • Modify or Extend C++ Code: Depending on the complexity of the vertical handover mechanism, we need to write or adjust the C++ classes in NS2. For instance we might expand the MobileNode class to handle multiple interfaces and execute the actual handover logic in C++.
  • Recompile NS2: After generating variation to the C++ code, recompile NS2 to contain the modifications.
  1. Simulate the Handover Process
  • Run the Simulation: Implement Tcl script to execute the simulation. During the simulation, the mobile node should switch from one network to another according to the implemented condition.
  • Trace Files: measure the trace files produced by NS2 to validate that the handover occurred properly and measure the performance.
  1. Analyze and Optimize
  • Performance Metrics: To assess the parameters like handover latency, packet loss, and throughput to measure the efficiency of the handover process.
  • Optimization: To enhance the handover decision techniques to minimize handover delay and packet loss. To deliberately handling the adding more sophisticated decision conditions such as network load or user preferences.
  1. Document Your Implementation
  • Documentation: Write elaborated documentation explaining the topology, handover decision technique, simulation setup, and analysis.
  • Reporting: Make a report for academic or research purposes that describe the findings and conclusions.
  1. Advanced Topics
  • Multiple Handover Scenarios: To emulate multiple handover scenarios like from Wi-Fi to LTE, LTE to 5G, etc.
  • QoS Considerations: Execute QoS (Quality of Service) that deliberates during handover; make sure that on-going connections are sustained with minimal degradation.

Example Advanced Handover Decision Logic in C++ (Pseudocode)

void MobileNode::handover() {

double wifi_signal = getSignalStrength(“Wi-Fi”);

double lte_signal = getSignalStrength(“LTE”);

if (wifi_signal < THRESHOLD && lte_signal > wifi_signal) {

switchInterface(“LTE”);

} else if (lte_signal < THRESHOLD && wifi_signal > lte_signal) {

switchInterface(“Wi-Fi”);

}

}

void MobileNode::switchInterface(string interface) {

if (interface == “LTE”) {

currentInterface = LTE;

} else if (interface == “Wi-Fi”) {

currentInterface = WIFI;

}

// Additional logic to handle interface switch

}

From the above implementation process demonstrate how to execute the vertical handover in the network through ns2 tool. Additional specific details about the vertical handover will also be provided.

The ns2projects.com team is working on Vertical Handover project ideas that are well-aligned with the topic. If you need help with network performance, just share your details with us, and we’ll provide you with the best results and a thorough outcome.