To implement the network collision avoidance in ns3, it is foremost step in the implementation of wireless networks. To prevent the packet collisions, we have to create the simulation that has preventing mechanisms. In the wireless network, we implement the collision avoidance using Carrier Sense Multiple Access with collision avoidance (CSMA/CA) protocol. Let’s get started with step by step procedure on how to implement network collision avoidance in ns3.
Step-by-Step Implementation:
Step 1: Setup ns3 Environment
Make sure that ns3 is installed in your computer and checks if it is properly configured.
git clone https://gitlab.com/nsnam/ns-3-dev.git
cd ns-3-dev
./waf configure
./waf build
Step 2: Create the Simulation Script
We will create a simulation script that sets up a wireless network using the CSMA/CA protocol. This script will include nodes, Wi-Fi devices, mobility models, and applications to generate traffic.
#include “ns3/core-module.h”
#include “ns3/network-module.h”
#include “ns3/internet-module.h”
#include “ns3/mobility-module.h”
#include “ns3/wifi-module.h”
#include “ns3/applications-module.h”
#include “ns3/netanim-module.h”
using namespace ns3;
NS_LOG_COMPONENT_DEFINE(“NetworkCollisionAvoidance”);
int main(int argc, char *argv[])
{
CommandLine cmd;
cmd.Parse(argc, argv);
// Create nodes
NodeContainer wifiStaNodes;
wifiStaNodes.Create(5); // Create 5 stations
NodeContainer wifiApNode;
wifiApNode.Create(1); // Create 1 access point
// Set up Wi-Fi channel
YansWifiChannelHelper channel = YansWifiChannelHelper::Default();
YansWifiPhyHelper phy = YansWifiPhyHelper::Default();
phy.SetChannel(channel.Create());
// Set up Wi-Fi and CSMA/CA
WifiHelper wifi;
wifi.SetStandard(WIFI_PHY_STANDARD_80211g);
WifiMacHelper mac;
Ssid ssid = Ssid(“ns-3-ssid”);
// Set up STA (Station) devices
mac.SetType(“ns3::StaWifiMac”,
“Ssid”, SsidValue(ssid),
“ActiveProbing”, BooleanValue(false));
NetDeviceContainer staDevices = wifi.Install(phy, mac, wifiStaNodes);
// Set up AP (Access Point) device
mac.SetType(“ns3::ApWifiMac”,
“Ssid”, SsidValue(ssid));
NetDeviceContainer apDevice = wifi.Install(phy, mac, wifiApNode);
// Install Internet stack
InternetStackHelper stack;
stack.Install(wifiApNode);
stack.Install(wifiStaNodes);
// Assign IP addresses
Ipv4AddressHelper address;
address.SetBase(“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer staInterfaces = address.Assign(staDevices);
Ipv4InterfaceContainer apInterface = address.Assign(apDevice);
// Set up mobility model
MobilityHelper mobility;
// Mobility for the AP
mobility.SetMobilityModel(“ns3::ConstantPositionMobilityModel”);
mobility.Install(wifiApNode);
// Mobility for the STAs
mobility.SetMobilityModel(“ns3::RandomWalk2dMobilityModel”,
“Bounds”, RectangleValue(Rectangle(-50, 50, -50, 50)));
mobility.Install(wifiStaNodes);
// Install applications (e.g., UDP echo for sensing data)
uint16_t port = 9;
UdpEchoServerHelper echoServer(port);
ApplicationContainer serverApps = echoServer.Install(wifiApNode.Get(0));
serverApps.Start(Seconds(1.0));
serverApps.Stop(Seconds(20.0));
UdpEchoClientHelper echoClient(apInterface.GetAddress(0), port);
echoClient.SetAttribute(“MaxPackets”, UintegerValue(100));
echoClient.SetAttribute(“Interval”, TimeValue(Seconds(1.0)));
echoClient.SetAttribute(“PacketSize”, UintegerValue(1024));
ApplicationContainer clientApps = echoClient.Install(wifiStaNodes);
clientApps.Start(Seconds(2.0));
clientApps.Stop(Seconds(20.0));
// Enable animation
AnimationInterface anim(“collision-avoidance-animation.xml”);
Simulator::Stop(Seconds(20.0));
Simulator::Run();
Simulator::Destroy();
return 0;
}
Step 3: Compile and Run the Simulation
- Compile the Simulation:
./waf configure –enable-examples
./waf build
Run the Simulation:
./waf –run scratch/<your-simulation-script>
Step 4: Analyze Results
If we want to visualize the simulation results we can use the NetAnim tool.
netanim collision-avoidance-animation.xml
Step 5: Advanced Features
To extend the functionality of your network collision avoidance simulation, we can consider the following steps:
1. Dynamic Channel Assignment
To minimize collisions, we can implement a mechanism which helps to dynamically assign channels to nodes.
2. Enhanced Mobility Models
We can create a realistic mobility traces with the help of tool named SUMO (Simulation of Urban MObility) tool and import the tool into ns3.
3. Data Collection and Analysis
If we want to analyze the effectiveness of collision avoidance mechanisms, we can simply accumulate data during collision rates, throughput, and delay.
#include “ns3/core-module.h”
#include “ns3/network-module.h”
#include “ns3/internet-module.h”
#include “ns3/mobility-module.h”
#include “ns3/wifi-module.h”
#include “ns3/applications-module.h”
#include “ns3/netanim-module.h”
using namespace ns3;
NS_LOG_COMPONENT_DEFINE(“NetworkCollisionAvoidance”);
int main(int argc, char *argv[])
{
CommandLine cmd;
cmd.Parse(argc, argv);
// Create nodes
NodeContainer wifiStaNodes;
wifiStaNodes.Create(5); // Create 5 stations
NodeContainer wifiApNode;
wifiApNode.Create(1); // Create 1 access point
// Set up Wi-Fi channel
YansWifiChannelHelper channel = YansWifiChannelHelper::Default();
YansWifiPhyHelper phy = YansWifiPhyHelper::Default();
phy.SetChannel(channel.Create());
// Set up Wi-Fi and CSMA/CA
WifiHelper wifi;
wifi.SetStandard(WIFI_PHY_STANDARD_80211g);
WifiMacHelper mac;
Ssid ssid = Ssid(“ns-3-ssid”);
// Set up STA (Station) devices
mac.SetType(“ns3::StaWifiMac”,
“Ssid”, SsidValue(ssid),
“ActiveProbing”, BooleanValue(false));
NetDeviceContainer staDevices = wifi.Install(phy, mac, wifiStaNodes);
// Set up AP (Access Point) device
mac.SetType(“ns3::ApWifiMac”,
“Ssid”, SsidValue(ssid));
NetDeviceContainer apDevice = wifi.Install(phy, mac, wifiApNode);
// Install Internet stack
InternetStackHelper stack;
stack.Install(wifiApNode);
stack.Install(wifiStaNodes);
// Assign IP addresses
Ipv4AddressHelper address;
address.SetBase(“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer staInterfaces = address.Assign(staDevices);
Ipv4InterfaceContainer apInterface = address.Assign(apDevice);
// Set up mobility model
MobilityHelper mobility;
// Mobility for the AP
mobility.SetMobilityModel(“ns3::ConstantPositionMobilityModel”);
mobility.Install(wifiApNode);
// Mobility for the STAs
mobility.SetMobilityModel(“ns3::RandomWalk2dMobilityModel”,
“Bounds”, RectangleValue(Rectangle(-50, 50, -50, 50)));
mobility.Install(wifiStaNodes);
// Install applications (e.g., UDP echo for sensing data)
uint16_t port = 9;
UdpEchoServerHelper echoServer(port);
ApplicationContainer serverApps = echoServer.Install(wifiApNode.Get(0));
serverApps.Start(Seconds(1.0));
serverApps.Stop(Seconds(20.0));
UdpEchoClientHelper echoClient(apInterface.GetAddress(0), port);
echoClient.SetAttribute(“MaxPackets”, UintegerValue(100));
echoClient.SetAttribute(“Interval”, TimeValue(Seconds(1.0)));
echoClient.SetAttribute(“PacketSize”, UintegerValue(1024));
ApplicationContainer clientApps = echoClient.Install(wifiStaNodes);
clientApps.Start(Seconds(2.0));
clientApps.Stop(Seconds(20.0));
// Enable animation
AnimationInterface anim(“collision-avoidance-animation.xml”);
// Enable packet metadata and tracing
wifiPhy.EnablePcap(“collision-avoidance”, apDevice.Get(0));
Simulator::Stop(Seconds(20.0));
Simulator::Run();
Simulator::Destroy();
return 0;
}
In Conclusion, with the help of the procedure that we provided we can fully understands the steps involving in the implementation process on how to implement network collision avoidance in ns3. As per your need, we can provide any extra implementation and information about the collision avoidance in ns3 for further use.