To simulate Heterogeneous Networks (HetNets) using NS2, which encompasses modeling several network technologies (such as Wi-Fi, cellular, wired, etc.) that coexist and interact with each other. A Heterogeneous Network normally incorporates distinct kinds of communication systems, and the nodes within these networks can switch among or use numerous technologies to enhance the network performance, reliability, and coverage.
Below is a step-by-step simplified approach on how to simulate Heterogeneous Networks (HetNets) projects using NS2.
Steps to Simulate Heterogeneous Networks Projects in NS2
- Install NS2
Initially, we must have NS2 installed on the system. We can download NS2 from the NS2 website.
- Basic Concept of Heterogeneous Networks
Heterogeneous Networks (HetNets) normally contain distinct kinds of nodes, which utilize several communication technologies. For instance:
- Wi-Fi (IEEE 802.11): High-bandwidth but short-range communication.
- LTE/4G/5G: Cellular technologies, which provide broad coverage however have distinct performance characteristics.
- Wired Networks: Offer high bandwidth however are stationary.
We can model these communication technologies and their interactions utilizing NS2 by making distinct kinds of nodes (e.g., mobile devices, base stations, access points, etc.) and using a combination of wireless and wired communication protocols.
- Create a Heterogeneous Network Topology
In this stage, we will configure distinct types of nodes (e.g., Wi-Fi, LTE, wired) and we describe communication links among them.
Example TCL Script for HetNet Simulation:
# Create an NS2 simulator instance
set ns [new Simulator]
# Define two types of wireless networks (e.g., Wi-Fi and LTE)
# Create Wi-Fi nodes
set wifi_ap [new Node] ;# Wi-Fi Access Point
set wifi_node [new Node] ;# Wi-Fi Node (User Device)
# Create LTE nodes
set lte_bs [new Node] ;# LTE Base Station
set lte_ue [new Node] ;# LTE User Equipment
# Define a wired backbone network
set router [new Node] ;# Wired router connecting Wi-Fi and LTE networks
# Create the link between Wi-Fi AP and wired router
$ns duplex-link $wifi_ap $router 100Mb 10ms DropTail
# Create the link between LTE BS and wired router
$ns duplex-link $lte_bs $router 100Mb 10ms DropTail
# Set up communication within Wi-Fi (wireless communication between AP and node)
set chan_wifi [new Channel/WirelessChannel]
$ns set wirelessChannel_ $chan_wifi
$ns duplex-link $wifi_ap $wifi_node 1Mb 20ms DropTail
# Set up communication within LTE (wireless communication between BS and UE)
set chan_lte [new Channel/WirelessChannel]
$ns set wirelessChannel_ $chan_lte
$ns duplex-link $lte_bs $lte_ue 5Mb 30ms DropTail
# Set up UDP agents for communication
set udp_wifi [new Agent/UDP]
set sink_wifi [new Agent/Null]
$ns attach-agent $wifi_node $udp_wifi
$ns attach-agent $lte_ue $sink_wifi
# Connect the Wi-Fi node to the LTE UE via the router
$ns connect $udp_wifi $sink_wifi
# Schedule transmissions (Wi-Fi node sends packets to LTE UE)
$ns at 1.0 “$udp_wifi send 500” # Wi-Fi node sends packet to LTE UE via the router
# Enable tracing for network analysis
set tracefile [open out.tr w]
$ns trace-all $tracefile
# Define simulation finish time
$ns at 10.0 “finish”
# Run the simulation
proc finish {} {
global ns tracefile
$ns flush-trace
close $tracefile
exec nam out.nam &
exit 0
}
$ns run
Explanation of the Script:
- Wi-Fi Network: The script makes a Wi-Fi access point (AP) and a Wi-Fi node (representing a user device) using a wireless channel.
- LTE Network: It also describes an LTE base station (BS) and an LTE user equipment (UE) node that communicate over a separate wireless channel.
- Wired Network: The Wi-Fi and LTE networks are attached to a wired router to mimic heterogeneous communication among wireless and wired technologies.
- Traffic Generation: The script makes UDP traffic among a Wi-Fi node and an LTE UE in which the packets traverse the wired router.
- Tracing and Analysis: Tracing is allowed to record the communication events in the network, and the NAM (Network Animator) is utilized for visualizing the simulation.
- Setting Up Different Communication Protocols
The simulation platform NS2 supports numerous communication protocols like TCP, UDP, 802.11, and cellular communication. In a HetNet scenario, each network may utilize a distinct protocol stack.
Wi-Fi Setup (Using IEEE 802.11):
To mimic a Wi-Fi network using the 802.11 protocol, we can use the following:
# Create a wireless node and configure it to use IEEE 802.11
set wifi_node [new Node]
$wifi_node set X_ 50.0
$wifi_node set Y_ 50.0
$wifi_node set Z_ 0.0
# Set up wireless communication with IEEE 802.11
$ns node-config -adhocRouting DSDV -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 OFF
LTE/Cellular Setup:
NS2 does not natively support LTE. We will require a patch or extension to replicate LTE or 5G. One such patch is LENA (LTE-EPC Network Simulator) or ns3 that supports more detailed LTE or 5G simulations. But, we can replicate simple cellular behaviours using custom wireless channels within NS2 as exposed in the simple instance above.
Wired Network Setup:
We can describe wired networks using duplex links among the nodes with metrics like bandwidth and delay. It is utilized for routers and core network communication.
$ns duplex-link $node1 $node2 100Mb 10ms DropTail
- Handoff and Mobility in Heterogeneous Networks
In HetNets, nodes may require to handoff among distinct network types (e.g., from Wi-Fi to LTE) as they move. We can replicate this mobility using NS2’s mobility models.
Example of Simulating Node Mobility:
# Set the initial position of the Wi-Fi node
$wifi_node set X_ 100.0
$wifi_node set Y_ 50.0
# Schedule a movement of the Wi-Fi node (simulating handoff from Wi-Fi to LTE)
$ns at 2.0 “$wifi_node setdest 150.0 100.0 10.0”
$ns at 4.0 “$wifi_node setdest 200.0 150.0 10.0”
It can be integrated with handoff logic to switch among distinct communication technologies as the node moves out of the coverage area of one technology and into another.
- Analysis and Performance Metrics
In heterogeneous network simulations, we will usually need to examine parameters like:
- Throughput: The rate at which data is effectively sent across the network.
- Latency: The time taken for a packet to travel from origin to destination across distinct technologies.
- Handoff Delay: The time it takes for a mobile node to switch from one network (e.g., Wi-Fi) to another (e.g., LTE).
- Packet Loss: The amount of packets are dropped because of network congestion or handoff.
We can allow detailed tracing and recording within NS2 to capture these parameters, as shown in the instanace script.
# Enable packet-level tracing
set tracefile [open trace.tr w]
$ns trace-all $tracefile
After running the simulation, we can parse the trace file to extract performance parameters or envision the communication using NAM.
- Advanced HetNet Scenarios
Multi-Hop Communication:
We can prolong the HetNet simulation by making multi-hop communication paths in which data is sent via intermediate nodes.
# Create an intermediate router for multi-hop communication
$ns duplex-link $node1 $intermediate_router 10Mb 5ms DropTail
$ns duplex-link $intermediate_router $node2 10Mb 5ms DropTail
Dynamic Spectrum Sharing:
In HetNets, spectrum sharing among distinct wireless networks (e.g., Wi-Fi and LTE) can be mimicked by dynamically assigning bandwidth according to the traffic demand or interference.
QoS and Resource Allocation:
We can be launched Quality of Service (QoS) mechanisms to prioritize traffic from distinct networks and assign resources depends on application requirements.
In this projects, we had shown the basic guidelines on how you can simulate and set up the Heterogeneous networks and how to analyse the performance parameters then we also presented advanced scenarios using NS2 simulator. Upon request, we are furnished to deliver complete insights into this topic. phdprime.com will help you achieve optimal simulation results. Collaborate with us to discover the best project ideas for Heterogeneous Networks that align with your interests.
