How to Begin Implement a OFDM Wireless Communication in NS3

To create a OFDM (Orthogonal Frequency Division Multiplexing) wireless communication project using ns-3 includes the replicate of physical layer communication which uses a OFDM a modulation structure. Though ns3 doesn’t natively helps for low-level PHY layer OFDM executions, we can replicate the wireless networks such as WiFi, LTE, or 5G, that inherently use OFDM.

Here’s a step-by-step guide to get started:

Steps to Begin Implementing a OFDM Wireless Communication Projects Using NS3

Step 1: Understand OFDM Concepts

What is OFDM?
- OFDM spilt the high-data-rate signal in many lower data-rate subcarriers, are decreasing the inter-symbol interference (ISI) and refining the spectral efficiency.
Use Cases:
- WiFi such as 802.11n/ac/ax.
- LTE and 5G NR.
- Wireless MAN for instance WiMAX.
Metrics:
- It offers the parameter metrices such as throughput, bit error rate (BER), signal-to-noise ratio (SNR), spectral efficiency.

Step 2: Install and Configure ns-3

Download ns-3:
- Install the latest version from nsnam.org.
Enable Required Modules:
- Setting and build the ns-3 by WiFi, LTE, and PHY components:

./waf configure –enable-modules=wifi,lte,internet,mobility

./waf build

Verify Installation:
- It process the sample scripts for validate the setting:

./waf –run wifi-simple-infra

./waf –run lte-simple

Step 3: Define the Project Scope

Scenarios:
- Estimate the OFDM performance designed for WiFi or LTE networks.
- It replicates the PHY layer impact such as fading and noise.
- OFDM-based network for examine the throughput and latency.
Goals:
- Recognize on how well OFDM-based networks perform below various environments.
- Calculate the effect of mobility, interference, or channel fading.

Step 4: Set Up Network Topology

Create Nodes:
- Describe the access points (APs) and stations (STAs) for WiFi, or eNodeBs and UEs for LTE:

NodeContainer wifiStaNodes, wifiApNodes;

wifiStaNodes.Create(5); // 5 stations

wifiApNodes.Create(1); // 1 access point

Set Up Mobility:
- Setting the mobility models for dynamic environments:

MobilityHelper mobility;

mobility.SetMobilityModel(“ns3::ConstantPositionMobilityModel”);

mobility.Install(wifiApNodes);

mobility.SetMobilityModel(“ns3::RandomWalk2dMobilityModel”,

“Bounds”, RectangleValue(Rectangle(-50, 50, -50, 50)));

mobility.Install(wifiStaNodes);

Step 5: Configure OFDM-Based Communication

WiFi Setup:
- Use WiFi with OFDM-based PHY layers such as 802.11a/n/ac:

YansWifiChannelHelper wifiChannel = YansWifiChannelHelper::Default();

YansWifiPhyHelper wifiPhy = YansWifiPhyHelper::Default();

wifiPhy.SetChannel(wifiChannel.Create());

WifiHelper wifi;

wifi.SetStandard(WIFI_PHY_STANDARD_80211n); // OFDM PHY layer

wifi.SetRemoteStationManager(“ns3::MinstrelWifiManager”);

WifiMacHelper wifiMac;

Ssid ssid = Ssid(“ns3-wifi”);

wifiMac.SetType(“ns3::StaWifiMac”, “Ssid”, SsidValue(ssid));

NetDeviceContainer staDevices = wifi.Install(wifiPhy, wifiMac, wifiStaNodes);

wifiMac.SetType(“ns3::ApWifiMac”, “Ssid”, SsidValue(ssid));

NetDeviceContainer apDevices = wifi.Install(wifiPhy, wifiMac, wifiApNodes);

LTE Setup:
- Use LTE by OFDMA for the PHY layer:

Ptr<LteHelper> lteHelper = CreateObject<LteHelper>();

Ptr<PointToPointEpcHelper> epcHelper = CreateObject<PointToPointEpcHelper>();

lteHelper->SetEpcHelper(epcHelper);

NodeContainer enbNodes, ueNodes;

enbNodes.Create(1);

ueNodes.Create(5);

NetDeviceContainer enbLteDevices = lteHelper->InstallEnbDevice(enbNodes);

NetDeviceContainer ueLteDevices = lteHelper->InstallUeDevice(ueNodes);

lteHelper->Attach(ueLteDevices, enbLteDevices.Get(0));

Assign IP Addresses:
- Setting the IP address for devices:

InternetStackHelper stack;

stack.Install(wifiStaNodes);

stack.Install(wifiApNodes);

Ipv4AddressHelper ipv4;

ipv4.SetBase(“192.168.1.0”, “255.255.255.0”);

ipv4.Assign(staDevices);

ipv4.Assign(apDevices);

Step 6: Add Traffic Applications

Install Applications:
- It replicate the data transfer among nodes:

uint16_t port = 9;

OnOffHelper onOff(“ns3::UdpSocketFactory”, Address(InetSocketAddress(Ipv4Address(“192.168.1.1”), port)));

onOff.SetAttribute(“DataRate”, StringValue(“10Mbps”));

onOff.SetAttribute(“PacketSize”, UintegerValue(1024));

ApplicationContainer apps = onOff.Install(wifiStaNodes.Get(0));

apps.Start(Seconds(1.0));

apps.Stop(Seconds(10.0));

Add a Packet Sink:
- Receive their packets is the AP or eNodeB:

PacketSinkHelper sink(“ns3::UdpSocketFactory”, InetSocketAddress(Ipv4Address::GetAny(), port));

ApplicationContainer sinkApps = sink.Install(wifiApNodes.Get(0));

sinkApps.Start(Seconds(0.0));

sinkApps.Stop(Seconds(10.0));

Step 7: Enable Tracing and Monitoring

Enable Tracing:
- The parameter metrices such as PHY and MAC layer actions:

wifiPhy.EnablePcap(“ofdm-wifi”, staDevices.Get(0));

Use FlowMonitor:
- Gather the data for network performance metrics:

FlowMonitorHelper flowMonitor;

Ptr<FlowMonitor> monitor = flowMonitor.InstallAll();

Step 8: Run the Simulation

Schedule and Start Simulation:
- Express the replication of duration and implement:

Simulator::Stop(Seconds(10.0));

Simulator::Run();

Simulator::Destroy();

Analyze Results:
- Use the outcomes like PCAP files and FlowMonitor data for estimate the performance metrics.

Step 9: Example: Simple OFDM WiFi Simulation

Here’s a simple script:

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/mobility-module.h”

#include “ns3/wifi-module.h”

#include “ns3/internet-module.h”

#include “ns3/applications-module.h”

using namespace ns3;

int main(int argc, char *argv[]) {