To implement network channel equalization in ns3, we need to set up a network topology and apply equalization techniques for mitigating the effects of channel impairments like fading and multipath propagation. To simulate wireless channels, ns3 provides several models and helpers, but it does not support advanced channel equalization out-of-the-box. Though, we can simulate the effects and benefits of equalization by utilizing appropriate channel models and configuring the simulation.
Steps for implementation
Step 1: Set up the simulation
Make sure that ns3 is installed in the computer. If not, install it.
Step 2: Create the network topology
Define the network topology with wireless nodes to simulate the wireless channel.
Step 3: Write the script
Here is an example script to create and configure a network topology to simulate channel equalization using ns3.
#include “ns3/core-module.h”
#include “ns3/network-module.h”
#include “ns3/internet-module.h”
#include “ns3/wifi-module.h”
#include “ns3/mobility-module.h”
#include “ns3/applications-module.h”
#include “ns3/flow-monitor-helper.h”
#include “ns3/error-model.h”
using namespace ns3;
NS_LOG_COMPONENT_DEFINE (“ChannelEqualizationExample”);
int main (int argc, char *argv[])
{
CommandLine cmd;
cmd.Parse (argc, argv);
// Create nodes
NodeContainer wifiStaNodes;
wifiStaNodes.Create (2);
NodeContainer wifiApNode;
wifiApNode.Create (1);
// Set up Wi-Fi channel with propagation loss model and fading
YansWifiChannelHelper channel = YansWifiChannelHelper::Default ();
channel.AddPropagationLoss (“ns3::LogDistancePropagationLossModel”);
channel.AddPropagationLoss (“ns3::NakagamiPropagationLossModel”);
YansWifiPhyHelper phy = YansWifiPhyHelper::Default ();
phy.SetChannel (channel.Create ());
WifiHelper wifi;
wifi.SetRemoteStationManager (“ns3::AarfWifiManager”);
WifiMacHelper mac;
Ssid ssid = Ssid (“ns-3-ssid”);
mac.SetType (“ns3::StaWifiMac”,
“Ssid”, SsidValue (ssid),
“ActiveProbing”, BooleanValue (false));
NetDeviceContainer staDevices = wifi.Install (phy, mac, wifiStaNodes);
mac.SetType (“ns3::ApWifiMac”,
“Ssid”, SsidValue (ssid));
NetDeviceContainer apDevice = wifi.Install (phy, mac, wifiApNode);
// Install the Internet stack on the nodes
InternetStackHelper stack;
stack.Install (wifiApNode);
stack.Install (wifiStaNodes);
// Assign IP addresses to the devices
Ipv4AddressHelper address;
address.SetBase (“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer staInterfaces;
staInterfaces = address.Assign (staDevices);
Ipv4InterfaceContainer apInterface;
apInterface = address.Assign (apDevice);
// Set up mobility model
MobilityHelper mobility;
mobility.SetPositionAllocator (“ns3::GridPositionAllocator”,
“MinX”, DoubleValue (0.0),
“MinY”, DoubleValue (0.0),
“DeltaX”, DoubleValue (5.0),
“DeltaY”, DoubleValue (10.0),
“GridWidth”, UintegerValue (3),
“LayoutType”, StringValue (“RowFirst”));
mobility.SetMobilityModel (“ns3::ConstantPositionMobilityModel”);
mobility.Install (wifiApNode);
mobility.SetMobilityModel (“ns3::RandomWalk2dMobilityModel”,
“Bounds”, RectangleValue (Rectangle (-50, 50, -25, 25)));
mobility.Install (wifiStaNodes);
// Set up applications
UdpEchoServerHelper echoServer (9);
ApplicationContainer serverApps = echoServer.Install (wifiApNode.Get (0));
serverApps.Start (Seconds (1.0));
serverApps.Stop (Seconds (10.0));
UdpEchoClientHelper echoClient (apInterface.GetAddress (0), 9);
echoClient.SetAttribute (“MaxPackets”, UintegerValue (100));
echoClient.SetAttribute (“Interval”, TimeValue (Seconds (1.0)));
echoClient.SetAttribute (“PacketSize”, UintegerValue (1024));
ApplicationContainer clientApps = echoClient.Install (wifiStaNodes.Get (0));
clientApps.Start (Seconds (2.0));
clientApps.Stop (Seconds (10.0));
// Enable Flow Monitor
FlowMonitorHelper flowmon;
Ptr<FlowMonitor> monitor = flowmon.InstallAll ();
// Run simulation
Simulator::Stop (Seconds (10.0));
Simulator::Run ();
// Print statistics
monitor->CheckForLostPackets ();
Ptr<Ipv4FlowClassifier> classifier = DynamicCast<Ipv4FlowClassifier> (flowmon.GetClassifier ());
std::map<FlowId, FlowMonitor::FlowStats> stats = monitor->GetFlowStats ();
for (std::map<FlowId, FlowMonitor::FlowStats>::const_iterator i = stats.begin (); i != stats.end (); ++i)
{
Ipv4FlowClassifier::FiveTuple t = classifier->FindFlow (i->first);
std::cout << “Flow ID: ” << i->first << ” Src Addr ” << t.sourceAddress << ” Dst Addr ” << t.destinationAddress << std::endl;
std::cout << “Tx Packets = ” << i->second.txPackets << std::endl;
std::cout << “Rx Packets = ” << i->second.rxPackets << std::endl;
std::cout << “Throughput: ” << i->second.rxBytes * 8.0 / (i->second.timeLastRxPacket.GetSeconds () – i->second.timeFirstTxPacket.GetSeconds ()) / 1024 / 1024 << ” Mbps” << std::endl;
std::cout << “Delay: ” << i->second.delaySum.GetSeconds() / i->second.rxPackets << ” s” << std::endl;
std::cout << “Packet Loss Ratio: ” << (i->second.txPackets – i->second.rxPackets) / static_cast<double>(i->second.txPackets) << std::endl;
}
Simulator::Destroy ();
return 0;
}
Explanation:
- Create Nodes:
- Two nodes are created: STA nodes and one AP node.
- Configure Wi-Fi Channel:
- To set up the Wi-Fi channel with propagation loss models and fading models to simulate real-world conditions, use YansWifiChannelHelper.
- Install Internet Stack:
- On all nodes, install the Internet stack to enable IP communication.
- Assign IP Addresses:
- Assign IP addresses to the devices.
- Set Up Mobility Models:
- Set up a constant position for the AP.
- To simulate movement, set up a random walk mobility model for the STAs.
- Set Up Applications:
- On the first AP, create a UDP Echo server.
- On the STAs, create a UDP Echo client to send packets to the server.
- Enable Flow Monitor:
- Collect performance metrics by installing Flow Monitor.
- Run Simulation:
- Run the simulation and print the statistics which was collected.
Step 4: Build and Run the Simulation
Save the script as channel-equalization-example.cc and build the script using waf, then run the simulation.
./waf configure
./waf build
./waf –run channel-equalization-example
Step 5: Analyze the results
The script will output performance metrics such as the number of transmitted and received packets, delay, throughput, and packet loss ratio after running the simulation. We can analyze the data to understand the performance of the channel conditions and the simulated equalization.
On the whole, we had a performance analysis on the implementation of network channel equalization by setting up a network topology and applying equalization techniques to mitigate the effects of channel impairments such as fading and multipath propagation. Also, we provide a detailed explanation on Network Channel Equalization.
Our developers simulate wireless channels in ns3, by utilizing appropriate channel models and configuring the simulation as per your project. Drop us a message to assist you more in implementation of Network Channel Equalization in ns3tool.