How to Implement Spectrum Allocation in ns3

To implement the spectrum allocation in ns3, we need to setup the simulation where various nodes can enthusiastically allocate and utilize the portion of the spectrum. This is usually helpful in this type network like cognitive radio networks or dynamic spectrum access networks. Here, we provide the step by procedure to implement the spectrum allocation in ns3:

Step-by-Step Implementation:

Step 1: Set Up the ns3 Environment

1. Install ns3: Make certain ns3 is installed on the computer.

sudo apt-get update

sudo apt-get install ns3

Create a New ns3 Project: Create a directory for your new project within the ns3 workspace.

cd ns-3

mkdir scratch/spectrum-allocation

Step 2: Understand Spectrum Models in ns3

ns3 offers several models and helpers for spectrum-based simulations:

• SpectrumChannel: Generic channel model for spectrum-based communication.
• SpectrumWifiPhy: PHY layer for WiFi that uses spectrum channels.
• SpectrumPropagationLossModel: Models propagation loss in a spectrum-aware manner.

Step 3: Create a Simulation Script for Spectrum Allocation

1. Create a New Simulation Script: Create a new script in your scratch directory to implement the spectrum allocation scenario.

// spectrum-allocation.cc

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

#include “ns3/spectrum-module.h”

#include “ns3/mobility-module.h”

#include “ns3/wifi-module.h”

using namespace ns3;

NS_LOG_COMPONENT_DEFINE (“SpectrumAllocation”);

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

CommandLine cmd;

cmd.Parse (argc, argv);

// Create nodes

NodeContainer wifiStaNodes;

wifiStaNodes.Create (2);

NodeContainer wifiApNode = wifiStaNodes.Get (0);

// Set up spectrum channel

Ptr<SpectrumChannel> spectrumChannel = CreateObject<SpectrumChannel> ();

Ptr<MultiModelSpectrumChannel> spectrumChannel = CreateObject<MultiModelSpectrumChannel> ();

// Set up propagation loss model

Ptr<SpectrumPropagationLossModel>lossModel=CreateObject<FriisSpectrumPropagationLossModel> ();

spectrumChannel->AddPropagationLossModel (lossModel);

// Set up spectrum wifi phy

SpectrumWifiPhyHelper spectrumPhy = SpectrumWifiPhyHelper::Default ();

spectrumPhy.SetChannel (spectrumChannel);

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 (spectrumPhy, mac, wifiStaNodes);

mac.SetType (“ns3::ApWifiMac”,

“Ssid”, SsidValue (ssid));

NetDeviceContainer apDevices = wifi.Install (spectrumPhy, mac, wifiApNode);

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 (wifiStaNodes);

InternetStackHelper stack;

stack.Install (wifiStaNodes);

Ipv4AddressHelper address;

address.SetBase (“10.1.1.0”, “255.255.255.0”);

Ipv4InterfaceContainer staInterfaces = address.Assign (staDevices);

Ipv4InterfaceContainer apInterface = address.Assign (apDevices);

UdpEchoServerHelper echoServer (9);

ApplicationContainer serverApp = echoServer.Install (wifiApNode);

serverApp.Start (Seconds (1.0));

serverApp.Stop (Seconds (10.0));

UdpEchoClientHelper echoClient (apInterface.GetAddress (0), 9);

echoClient.SetAttribute (“MaxPackets”, UintegerValue (1));

echoClient.SetAttribute (“Interval”, TimeValue (Seconds (1.0)));

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

ApplicationContainer clientApp = echoClient.Install (wifiStaNodes.Get (1));

clientApp.Start (Seconds (2.0));

clientApp.Stop (Seconds (10.0));

Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

Simulator::Stop (Seconds (10.0));

Simulator::Run ();

Simulator::Destroy ();

return 0;

}

Compile the Script: Compile your script using the waf build system.

./waf build

Run the Simulation: Run your simulation script and observe the results.

./waf –run scratch/spectrum-allocation

Step 4: Enable Dynamic Spectrum Allocation

1. Implement Spectrum Allocation Functionality: we need to generate the mechanism for heterogeneously allocating the spectrum. This can be completed by regulating the frequency channel of the nodes during the simulation. Here we provide the sample on how to do that:

// spectrum-allocation.cc (Continued)

#include “ns3/wifi-spectrum-value-helper.h”

void ChangeChannelFrequency(Ptr<NetDevice> device, double newFrequency) {

Ptr<WifiNetDevice> wifiDevice = DynamicCast<WifiNetDevice>(device);

if (wifiDevice) {

Ptr<SpectrumWifiPhy> spectrumPhy = DynamicCast<SpectrumWifiPhy>(wifiDevice->GetPhy());

if (spectrumPhy) {

Ptr<SpectrumValue> spectrumValue = WifiSpectrumValueHelper::CreateRfSpectrumValue(newFrequency);

spectrumPhy->SetTxPowerSpectralDensity(spectrumValue);

}

}

}

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

// (Previous setup code)

Simulator::Schedule(Seconds(5.0), &ChangeChannelFrequency, staDevices.Get(0), 5180e6);

Simulator::Schedule(Seconds(5.0), &ChangeChannelFrequency, apDevices.Get(0), 5180e6);

// (Previous simulation code)

}

Step 5: Enable Tracing and Analyse Results

1. Enable Tracing: Add tracing to collect data for analysis.

AsciiTraceHelper ascii;

spectrumPhy.EnableAsciiAll(ascii.CreateFileStream(“spectrum-allocation.tr”));

Run the Simulation: Set the simulation stop time and run it.

Simulator::Stop(Seconds(10.0));

Simulator::Run();

Simulator::Destroy();

Step 6: Analyse the Results

After running the simulation, analyse the generated trace files (spectrum-allocation.tr) to study the spectrum allocation dynamics and its impact on network performance.

In the end, we all get the knowledge about how to allocate the spectrum allocation to the network using the ns3 tool. We will give the elaborate additional details on how the spectrum allocation will perform in other simulation framework.

We offer comparative analysis on Spectrum Allocation in ns3 simulation. Our expertise lies in cognitive radio networks (CRNs) and dynamic spectrum access networks. Feel free to reach out to ns3simulation.com for further guidance.