To implement the network spectral efficiency in ns3 has includes setup the emulation that can estimate the effectiveness of spectrum usage by the network. This usually measured in terms of bits per second per Hertz (bps/Hz) and can be deliberate by dividing the data rate by the bandwidth. The given below is the detailed procedure on how to implement the network spectral efficiency in ns3:
Step-by-Step Implementation:
- Set up ns3 Environment
Make certain ns3 is installed in the computer.
- Create a New Simulation Script
Create a new C++ script for your simulation. For this example, we will use C++.
- Include Necessary Headers
Include the necessary ns3 headers in your script.
#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-module.h”
4. Define the Network Topology
Set up the basic network topology, including nodes, devices, and links.
using namespace ns3;
NS_LOG_COMPONENT_DEFINE (“SpectralEfficiencyExample”);
void CalculateSpectralEfficiency (FlowMonitorHelper &flowHelper, Ptr<FlowMonitor> flowMonitor, double bandwidth) {
flowMonitor->CheckForLostPackets ();
std::map<FlowId, FlowMonitor::FlowStats> stats = flowMonitor->GetFlowStats ();
double totalDataRate = 0.0;
for (std::map<FlowId, FlowMonitor::FlowStats>::const_iterator iter = stats.begin (); iter != stats.end (); ++iter) {
double dataRate = iter->second.rxBytes * 8.0 / (iter->second.timeLastRxPacket.GetSeconds () – iter->second.timeFirstTxPacket.GetSeconds ());
totalDataRate += dataRate;
}
double spectralEfficiency = totalDataRate / bandwidth;
std::cout << “Total Data Rate: ” << totalDataRate << ” bps” << std::endl;
std::cout << “Spectral Efficiency: ” << spectralEfficiency << ” bps/Hz” << std::endl;
}
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
YansWifiChannelHelper channel = YansWifiChannelHelper::Default ();
YansWifiPhyHelper phy = YansWifiPhyHelper::Default ();
phy.SetChannel (channel.Create ());
WifiHelper wifi;
wifi.SetStandard (WIFI_STANDARD_80211n);
WifiMacHelper mac;
Ssid ssid = Ssid (“ns3-wifi”);
mac.SetType (“ns3::StaWifiMac”, “Ssid”, SsidValue (ssid));
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
InternetStackHelper stack;
stack.Install (wifiApNode);
stack.Install (wifiStaNodes);
Ipv4AddressHelper address;
address.SetBase (“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer staInterfaces = address.Assign (staDevices);
Ipv4InterfaceContainer apInterface = address.Assign (apDevice);
// Set mobility
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);
mobility.Install (wifiApNode);
// Install applications
uint16_t port = 9;
OnOffHelper onoff (“ns3::UdpSocketFactory”, Address (InetSocketAddress (apInterface.GetAddress (0), port)));
onoff.SetAttribute (“OnTime”, StringValue (“ns3::ConstantRandomVariable[Constant=1]”));
onoff.SetAttribute (“OffTime”, StringValue (“ns3::ConstantRandomVariable[Constant=0]”));
onoff.SetAttribute (“DataRate”, DataRateValue (DataRate (“54Mbps”)));
onoff.SetAttribute (“PacketSize”, UintegerValue (1024));
ApplicationContainer apps = onoff.Install (wifiStaNodes);
apps.Start (Seconds (1.0));
apps.Stop (Seconds (10.0));
PacketSinkHelper sink (“ns3::UdpSocketFactory”, InetSocketAddress (Ipv4Address::GetAny (), port));
ApplicationContainer sinkApps = sink.Install (wifiApNode);
sinkApps.Start (Seconds (0.0));
sinkApps.Stop (Seconds (10.0));
// Set up flow monitor
FlowMonitorHelper flowHelper;
Ptr<FlowMonitor> flowMonitor = flowHelper.InstallAll ();
// Run simulation
Simulator::Stop (Seconds (10.0));
Simulator::Run ();
// Calculate spectral efficiency
double bandwidth = 20e6; // 20 MHz for 802.11n
CalculateSpectralEfficiency (flowHelper, flowMonitor, bandwidth);
Simulator::Destroy ();
return 0;
}
Explanation
- Network Topology: The script sets up a Wi-Fi network with two STA nodes and one AP node.
- Wi-Fi Setup: The Wi-Fi network uses the 802.11n standard, and the nodes are configured with constant position mobility.
- Applications: OnOff applications are installed on the STA nodes to generate UDP traffic to the AP node. A PacketSink application is installed on the AP node to receive the traffic.
- Flow Monitor: FlowMonitor is used to collect network statistics, which are necessary to calculate the spectral efficiency.
- Spectral Efficiency Calculation: The CalculateSpectralEfficiency function computes the total data rate received by all nodes and divides it by the bandwidth to get the spectral efficiency.
5. Build and Run the Script
Save the script and build it using the ns3 builds system (waf).
./waf configure
./waf build
./waf –run your-script-name
In the whole, we have shown that the network spectral efficiency has involves setting up the basic network topology that contains nodes, devices, and links to generate UDP traffic to the AP node to receive the traffic and then computes the total data rate received by all nodes and divides it by the bandwidth to get the spectral efficiency and finally we run the simulation using ns3 to get the output. Also we provide the elaborated details about network spectral efficiency.
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