How to Begin Implementing a Heterogeneous Networks in NS3

To create an estimate of Heterogeneous Networks (HetNet) project in ns-3 has includes the replicate of network by various kind of permits the technology like as LTE, WiFi, 5G and others. The aim is to examine the interactions, handovers, and resource allocation in such environments. Below is a comprehensive guide to help you get started:

Steps to Begin Implementing a Heterogeneous Networks Projects Using NS3

Step 1: Understand Heterogeneous Networks (HetNets)

• HetNet Definition:
  • The networks are collected the various permit the technologies and perform the both enhance the coverage, capacity, and reliability.
• Use Cases:
  • LTE + WiFi offloading.
  • It minimum cell deployment by macro cells.
  • Incorporate the 5G by legacy networks.
• Components:
  • The heterogeneous network has contains the components they are macro cells, minimum cells, WiFi access points (APs), and mobile devices (UEs).

Step 2: Install and Configure ns-3

1. Download ns-3:
   • Install ns-3 from the official website.
2. Enable Required Modules:
   • It contain the helps for for LTE, WiFi, and Mobility modules:

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

./waf build

1. Verify Installation:
   • Process for the simple scripts:

./waf –run lte-simple

./waf –run wifi-simple-infra

Step 3: Define the Project Scope

• Scenarios:
  • This environment has LTE and WiFi coexistence by congestion for offloading.
  • It minimum cell densification for enhancement the capacity.
  • HetNets provides the mobility management and handovers.
• Metrics:
  • This contains the performance of parameter metrices such as handover latency, throughput, delay, packet delivery ratio (PDR).

Step 4: Create the Network Topology

1. Node Creation:
   • Describe the nodes for macro cells, small cells, WiFi APs, and UEs:

NodeContainer macroCells, smallCells, wifiAps, ues;

macroCells.Create(1);

smallCells.Create(2);

wifiAps.Create(2);

ues.Create(10);

1. Install Network Stacks:
   • Install LTE and WiFi stacks:

InternetStackHelper internet;

internet.Install(ues);

internet.Install(wifiAps);

1. Set Up Mobility:
   • Setting the mobility for all nodes:

MobilityHelper mobility;

mobility.SetMobilityModel(“ns3::RandomWalk2dMobilityModel”,

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

mobility.Install(ues);

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

mobility.Install(macroCells);

mobility.Install(smallCells);

mobility.Install(wifiAps);

Step 5: Configure Access Technologies

1. LTE Configuration:
   • It configure the LTE eNodeB and assign the UEs:

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

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

lteHelper->SetEpcHelper(epcHelper);

NetDeviceContainer lteEnbDevices = lteHelper->InstallEnbDevice(macroCells);

NetDeviceContainer lteUeDevices = lteHelper->InstallUeDevice(ues);

lteHelper->Attach(lteUeDevices, lteEnbDevices.Get(0));

1. WiFi Configuration:
   • Setting a WiFi APs and linked the UEs:

YansWifiChannelHelper wifiChannel = YansWifiChannelHelper::Default();

YansWifiPhyHelper wifiPhy = YansWifiPhyHelper::Default();

wifiPhy.SetChannel(wifiChannel.Create());

WifiHelper wifi;

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

WifiMacHelper wifiMac;

Ssid ssid = Ssid(“ns3-wifi”);

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

NetDeviceContainer wifiStaDevices = wifi.Install(wifiPhy, wifiMac, ues);

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

NetDeviceContainer wifiApDevices = wifi.Install(wifiPhy, wifiMac, wifiAps);

Step 6: Implement Handover Logic

1. Enable LTE-WiFi Offloading:
   • It uses a select for offloading according to their metrics such as RSSI or load.

Simulator::Schedule(Seconds(10.0), &LteHelper::HandoverRequest, lteHelper,

lteUeDevices.Get(0), lteEnbDevices.Get(0), lteEnbDevices.Get(1));

1. Custom Handover Decision:
   • Write a function for dynamically switch among the LTE and WiFi based on environments:

void MonitorHandover() {

double rssiLte = GetLteRssi(ue);

double rssiWifi = GetWifiRssi(ue);

if (rssiWifi > rssiLte + threshold) {

// Switch to WiFi

wifiHelper.Associate(ue, wifiAp);

} else {

// Stay with LTE

lteHelper.Attach(ue, lteEnb);

}

}

1. Use Callbacks:
   • Track the movements such as handover initiation and completion:

Config::ConnectWithoutContext(“/NodeList/*/DeviceList/*/LteUeRrc/HandoverStart”,

MakeCallback(&HandoverStartCallback));

Step 7: Set Up Traffic Applications

1. Install Traffic Generators:
   • It replicate the uplink and downlink congestion:

OnOffHelper onOff(“ns3::UdpSocketFactory”, Address(InetSocketAddress(Ipv4Address(“7.0.0.1”), 80)));

onOff.SetAttribute(“DataRate”, StringValue(“1Mbps”));

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

ApplicationContainer apps = onOff.Install(ues);

apps.Start(Seconds(1.0));

apps.Stop(Seconds(20.0));

1. Enable Packet Sinks:
   • Receive the packets for detailed nodes:

PacketSinkHelper sink(“ns3::UdpSocketFactory”, Address(InetSocketAddress(Ipv4Address::GetAny(), 80)));

apps = sink.Install(macroCells.Get(0));

apps.Start(Seconds(1.0));

apps.Stop(Seconds(20.0));

Step 8: Analyze and Visualize Results

1. Enable FlowMonitor:
   • Gather the data and examine the metrics:

FlowMonitorHelper flowMonitor;

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

1. Enable Tracing:
   • Log movements for debugging in the ensure the trace files:

lteHelper->EnableTraces();

wifiPhy.EnablePcap(“wifi”, wifiStaDevices.Get(0));

1. Visualize:
   • It use the tools like NetAnim or Gnuplot for envision the replication.

Example: Basic HetNet Simulation Script

Here’s a minimal sample combining LTE and WiFi:

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/mobility-module.h”

#include “ns3/lte-module.h”

#include “ns3/wifi-module.h”

#include “ns3/applications-module.h”

using namespace ns3;

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

// Create nodes

NodeContainer macroCells, wifiAps, ues;

macroCells.Create(1);

wifiAps.Create(1);

ues.Create(5);

// Mobility

MobilityHelper mobility;

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

mobility.Install(macroCells);

mobility.Install(wifiAps);

mobility.SetMobilityModel(“ns3::RandomWalk2dMobilityModel”,

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

mobility.Install(ues);

// LTE

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

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

lteHelper->SetEpcHelper(epcHelper);

NetDeviceContainer lteEnbDevices = lteHelper->InstallEnbDevice(macroCells);

NetDeviceContainer lteUeDevices = lteHelper->InstallUeDevice(ues);

lteHelper->Attach(lteUeDevices, lteEnbDevices.Get(0));

// WiFi

YansWifiChannelHelper wifiChannel = YansWifiChannelHelper::Default();

YansWifiPhyHelper wifiPhy = YansWifiPhyHelper::Default();

wifiPhy.SetChannel(wifiChannel.Create());

WifiHelper wifi;

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

WifiMacHelper wifiMac;

Ssid ssid = Ssid(“ns3-wifi”);

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

NetDeviceContainer wifiStaDevices = wifi.Install(wifiPhy, wifiMac, ues);

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

NetDeviceContainer wifiApDevices = wifi.Install(wifiPhy, wifiMac, wifiAps);

// Traffic

OnOffHelper onOff(“ns3::UdpSocketFactory”, Address(InetSocketAddress(Ipv4Address(“7.0.0.1”), 80)));

onOff.SetAttribute(“DataRate”, StringValue(“1Mbps”));

ApplicationContainer apps = onOff.Install(ues);

apps.Start(Seconds(1.0));

apps.Stop(Seconds(20.0));

// Simulation

Simulator::Stop(Seconds(20.0));

Simulator::Run();

Simulator::Destroy();

return 0;

}

Here, we clearly learned and understand how to Heterogeneous Networks (HetNet) that were implemented in ns3 tool and that creates the various technologies and perform the both improve the coverage, capacity, and reliability. Further assistance regarding the project will be provided in another manual.