To simulate a Zigbee Topology using NS2 (Network Simulator 2), which needs to replicate a low-power that low-data-rate wireless network normally utilized for communication within IoT (Internet of Things) applications. Zigbee networks are constructed lying on the IEEE 802.15.4 standard and are comprehended for its mesh, star, or tree topologies, which permit the devices to communicate including low energy consumption.
While NS2 does not have direct support for Zigbee protocols are innovative, we can replicate the Zigbee-like networks by configuring the wireless nodes and then utilizing custom metrics to simulate the behavior of Zigbee nodes. We can design the Zigbee’s mesh topology, star topology, or tree topology by setting up wireless communication along with proper settings for range, data rate, and power consumption. The below guide will help you get started using NS2:
Steps to Simulate Zigbee Topology Projects in NS2
Step 1: Understand Zigbee Topology
In a Zigbee Network:
- Coordinator Node: These nodes handle the network and communicate with all other nodes.
- Router Nodes: Prolong the range of the network by sending the data amongst devices.
- End Devices: It communicate with routers or the coordinator and generally function within low-power modes.
- Mesh/Star/Tree Topology: Zigbee assists mesh, star, and tree topologies in which the devices can be communicated with the coordinator either directly or through several hops.
Step 2: Install the NS2 Zigbee Patch (Optional)
For a more exact simulation of Zigbee, we require installing an NS2 Zigbee patch, which contains the Zigbee functionality. If we don’t have the patch then we can estimate the Zigbee behavior with the help of wireless nodes and modifying communication metrics like transmission range, data rate, and power settings.
Step 3: Design the Zigbee Network Topology
In this example, we will replicate a Zigbee Mesh Topology, in which:
- A coordinator node handles the network.
- Numerous router nodes are prolonged the network range.
- Several end devices are communicated via routers to attain the coordinator.
Step 4: Create an NS2 TCL Script for Simulating a Zigbee Mesh Topology
Here is an NS2 TCL script, which replicates a Zigbee-like Mesh Topology utilizing wireless nodes with modified communication metrics.
Example: Zigbee-Like Mesh Topology Simulation in NS2
# Create a new NS2 simulator object
set ns [new Simulator]
# Define a wireless network with a predefined topology
# Create a wireless channel
set chan [new Channel/WirelessChannel]
# Define the network topology for Zigbee-like mesh network
set opt(chan) Channel/WirelessChannel ;# Wireless channel
set opt(prop) Propagation/TwoRayGround ;# Two-ray ground propagation model
set opt(netif) Phy/WirelessPhy ;# Wireless physical layer
set opt(mac) Mac/802_15_4 ;# Zigbee uses IEEE 802.15.4 MAC
set opt(ifq) Queue/DropTail/PriQueue ;# Queue type
set opt(ll) LL ;# Link layer type
set opt(ant) Antenna/OmniAntenna ;# Omnidirectional antenna
set opt(x) 500 ;# X dimension of the grid
set opt(y) 500 ;# Y dimension of the grid
set opt(seed) 0.0
set opt(tracing) 1
set opt(topology) “zigbee-mesh”
# Create the topology object
set topo [new Topography]
$topo load_flatgrid $opt(x) $opt(y)
# Create God (General Operations Director) object
create-god 10
# Configure the node creation parameters for wireless nodes
$ns node-config -adhocRouting AODV \
-llType $opt(ll) \
-macType $opt(mac) \
-ifqType $opt(ifq) \
-ifqLen 50 \
-antType $opt(ant) \
-propType $opt(prop) \
-phyType $opt(netif) \
-channelType $opt(chan) \
-topoInstance $topo \
-agentTrace ON \
-routerTrace ON \
-macTrace ON
# Define coordinator, routers, and end devices
set coordinator [$ns node] ;# Zigbee Coordinator
set router1 [$ns node] ;# Router 1
set router2 [$ns node] ;# Router 2
set router3 [$ns node] ;# Router 3
set end_device1 [$ns node] ;# End device 1
set end_device2 [$ns node] ;# End device 2
set end_device3 [$ns node] ;# End device 3
# Position the nodes (you can adjust the positions as needed)
$coordinator set X_ 250
$coordinator set Y_ 250
$coordinator set Z_ 0.0
$router1 set X_ 150
$router1 set Y_ 250
$router1 set Z_ 0.0
$router2 set X_ 350
$router2 set Y_ 250
$router2 set Z_ 0.0
$router3 set X_ 250
$router3 set Y_ 350
$router3 set Z_ 0.0
$end_device1 set X_ 100
$end_device1 set Y_ 250
$end_device1 set Z_ 0.0
$end_device2 set X_ 400
$end_device2 set Y_ 250
$end_device2 set Z_ 0.0
$end_device3 set X_ 250
$end_device3 set Y_ 400
$end_device3 set Z_ 0.0
# Define communication between coordinator, routers, and end devices
# Attach UDP agents to the end devices and coordinator
set udp_coordinator [new Agent/UDP]
set udp_end_device1 [new Agent/UDP]
set udp_end_device2 [new Agent/UDP]
set udp_end_device3 [new Agent/UDP]
$ns attach-agent $coordinator $udp_coordinator
$ns attach-agent $end_device1 $udp_end_device1
$ns attach-agent $end_device2 $udp_end_device2
$ns attach-agent $end_device3 $udp_end_device3
# Define a UDP sink on the coordinator
set udp_sink [new Agent/Null]
$ns attach-agent $coordinator $udp_sink
# Connect the end devices to the coordinator via the mesh routers
$ns connect $udp_end_device1 $udp_sink
$ns connect $udp_end_device2 $udp_sink
$ns connect $udp_end_device3 $udp_sink
# Define CBR traffic between the end devices and coordinator
set cbr1 [new Application/Traffic/CBR]
$cbr1 set packetSize_ 100
$cbr1 set interval_ 0.1
$cbr1 attach-agent $udp_end_device1
set cbr2 [new Application/Traffic/CBR]
$cbr2 set packetSize_ 100
$cbr2 set interval_ 0.1
$cbr2 attach-agent $udp_end_device2
set cbr3 [new Application/Traffic/CBR]
$cbr3 set packetSize_ 100
$cbr3 set interval_ 0.1
$cbr3 attach-agent $udp_end_device3
# Schedule the start of traffic
$ns at 1.0 “$cbr1 start”
$ns at 1.5 “$cbr2 start”
$ns at 2.0 “$cbr3 start”
# Trace file for recording the simulation events
set tracefile [open “zigbee_mesh.tr” w]
$ns trace-all $tracefile
# NAM file for network animation
set namfile [open “zigbee_mesh.nam” w]
$ns namtrace-all-wireless $namfile $opt(x) $opt(y)
# Define the finish procedure
proc finish {} {
global ns tracefile namfile
$ns flush-trace
close $tracefile
close $namfile
exec nam zigbee_mesh.nam &
exit 0
}
# Finish the simulation after 10 seconds
$ns at 10.0 “finish”
# Run the simulation
$ns run
Step 5: Explanation of the Script
- Wireless Channel Setup:
- For wireless communication, script makes a wireless channel (Channel/WirelessChannel) and exhausts the Two-Ray Ground Propagation Model. The physical layer is placed to replicate the IEEE 802.15.4 that is the foundation of Zigbee networks.
- Node Setup:
- A coordinator node is located at the center of the topology to handle the network.
- Router nodes and end devices are positioned at diverse locations around the coordinator to mimic a mesh topology in which devices can be communicated through numerous hops.
- Communication Setup:
- UDP agents are connected to the end devices, and CBR (Constant Bit Rate) traffic is made among the end devices and the coordinator. Each end device begins transmitting traffic at diverse times that mimicking the asynchronous communication.
- Tracing and Visualization:
- The script creates a trace file (zigbee_mesh.tr) to log every network events, and a NAM file (zigbee_mesh.nam) for envisioning the network topology as well as traffic flows.
Step 6: Run the Simulation
- We can save the script as zigbee_mesh.tcl.
- Execute the script within NS2:
ns zigbee_mesh.tcl
It will make two files:
- zigbee_mesh.tr: A trace files, which records the packet-level information.
- zigbee_mesh.nam: A NAM file for envisioning the network behavior in NAM.
Step 7: Visualize the Simulation Using NAM
To envision the Zigbee mesh topology using NAM:
nam zigbee_mesh.nam
In NAM, we will observe:
- The coordinator communicating with numerous end devices through the router nodes.
- Mesh topology with multi-hop communication in which routers are prolong the communication range.
Step 8: Analyze the Trace File
The trace file (zigbee_mesh.tr) encompasses in-depth data regarding the network events, like:
- Packet transmissions among the nodes.
- Packet drops or delays within communication.
We can utilize the AWK, Python, or other scripting tools to examine the trace file and extract key performance parameters, like:
- Packet delivery ratio (PDR).
- End-to-end delay.
- Throughput.
Step 9: Enhance the Simulation
Below is a few ways to improve the simulation:
- Add More Zigbee Features: Execute the aspects such as low power modes or Zigbee’s tree topology.
- Simulate Different Traffic Types: Contain other kinds of traffic, like FTP or HTTP, to design the real-world IoT applications.
- Simulate Failures: Launch node failures or communication range limitations to monitor how the network counters within a mesh topology.
- Measure Energy Consumption: Execute an energy models to mimic the low-power consumption normal in Zigbee networks.
- Increase the Scale: Insert additional routers and nodes to replicate the larger Zigbee network including complex communication patterns.
Through this manual, we had comprehensively demonstrated entire details and simulation instructions that help you to know the simulation and enhancement of Zigbee Topology using NS2 simulation environment. Likewise, we will also be delivered further advanced insights regarding these projects, if required. We help you with mesh, star, or tree topologies for your projects. If you want to simulate Zigbee Topology Projects using the NS2 tool, check out phdprime.com for the best solutions and guidance. You can also find great research ideas and topics that fit your needs.
