To implement multimedia transmission in ns3, we need to set-up a network. In this network multimedia data (such as video or audio) has to be transmitted from one node to another for evaluating the performance of multimedia applications under different network conditions. Here we had provided the steps guide on how to create a basic simulation for multimedia transmission using UDP in ns3.
Step-by-step guide to implement Multimedia Transmission:
- Set Up ns3 Environment
Make sure ns3 is installed on the system.
- Create a New Simulation Script
Create a new C++ script for simulation. For this example, we will use C++.
- Include Necessary Headers
The necessary ns3 headers has to be included in the script.
#include “ns3/core-module.h”
#include “ns3/network-module.h”
#include “ns3/internet-module.h”
#include “ns3/point-to-point-module.h”
#include “ns3/applications-module.h”
#include “ns3/wifi-module.h”
#include “ns3/mobility-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 (“MultimediaTransmissionExample”);
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 = 5000;
Address sinkAddress (InetSocketAddress (apInterface.GetAddress (0), port));
PacketSinkHelper packetSinkHelper (“ns3::UdpSocketFactory”, sinkAddress);
ApplicationContainer sinkApp = packetSinkHelper.Install (wifiApNode.Get (0));
sinkApp.Start (Seconds (1.0));
sinkApp.Stop (Seconds (10.0));
OnOffHelper onOffHelper (“ns3::UdpSocketFactory”, sinkAddress);
onOffHelper.SetAttribute(“OnTime”,StringValue (“ns3::ConstantRandomVariable[Constant=1]”));
onOffHelper.SetAttribute(“OffTime”,StringValue (“ns3::ConstantRandomVariable[Constant=0]”));
onOffHelper.SetAttribute (“DataRate”, DataRateValue (DataRate (“1Mbps”)));
onOffHelper.SetAttribute (“PacketSize”, UintegerValue (1024));
ApplicationContainer clientApps = onOffHelper.Install (wifiStaNodes.Get (0));
clientApps.Start (Seconds (2.0));
clientApps.Stop (Seconds (10.0));
// Set up flow monitor
FlowMonitorHelper flowmon;
Ptr<FlowMonitor> monitor = flowmon.InstallAll();
// Enable pcap tracing
phy.EnablePcap (“multimedia-transmission”, staDevices.Get (0));
// Run simulation
Simulator::Stop (Seconds (10.0));
Simulator::Run ();
// Print flow monitor 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);
NS_LOG_UNCOND (“Flow ” << i->first << ” (” << t.sourceAddress << ” -> ” << t.destinationAddress << “)”);
NS_LOG_UNCOND (” Tx Bytes: ” << i->second.txBytes);
NS_LOG_UNCOND (” Rx Bytes: ” << i->second.rxBytes);
NS_LOG_UNCOND (“Throughput: ” << i->second.rxBytes * 8.0 / (i->second.timeLastRxPacket.GetSeconds () – i->second.timeFirstTxPacket.GetSeconds ()) / 1024 << ” Kbps”);
}
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 one STA node to generate UDP traffic to the AP node, simulating multimedia transmission. A PacketSink application is installed on the AP node to receive the traffic.
- Flow Monitor: FlowMonitor is used to collect network statistics, which are printed at the end of the simulation.
- PCAP Tracing: PCAP tracing is enabled to capture packets for analysis.
5. Build and Run the Script
Save the script and build it using the ns3 build system (waf).
./waf configure
./waf build
./waf –run multimedia-transmission
Extending the Example
We can extend this example to include more complex multimedia transmission scenarios, such as:
- Video Streaming: Use a more realistic traffic generator that mimics video streaming behavior.
- QoS Support: To prioritize multimedia traffic we need to implement Quality of Service (QoS) features.
- Dynamic Network Conditions: Introduce mobility and varying network conditions to test the robustness of multimedia transmission.
An example given below on how to modify the script to include QoS support:
#include “ns3/qos-wifi-mac-helper.h”
// Replace the WifiMacHelper with QosWifiMacHelper
QosWifiMacHelper mac = QosWifiMacHelper::Default ();
// Set up QoS settings
mac.SetType (“ns3::StaWifiMac”,
“Ssid”, SsidValue (ssid),
“ActiveProbing”, BooleanValue (false));
// Continue with the rest of the script
In this example, the QosWifiMacHelper is used instead of WifiMacHelper to set up QoS support in the Wi-Fi network.
Finally, we had elaborately discussed about the implementation process of multimedia transmission in ns3 using UDP for simulation. And also we have discussed about the extending the script for including more complex multimedia transmission scenarios.Our team provides assistance with multimedia transmission in ns3, along with implementation support. Please stay connected with us to monitor the performance results of your project.