propagation loss models in ns3

[vishal kajjam]

Hi Everyone

I am having a problem when I add the any of the propagation loss models to the wifi channel. When I looked at the pcap file there ARP packets dont seem to be transmitted. Can anyone please tell me what the problem is? I have copied my code below

Regards

Vishal

#include "ns3/core-module.h"
#include "ns3/simulator-module.h"
#include "ns3/node-module.h"
#include "ns3/helper-module.h"
#include "ns3/wifi-module.h"
#include "ns3/mobility-module.h"

#include "ns3/flow-monitor-module.h"

//This is a simple example in order to show how 802.11n frame aggregation feature (A-MSDU) works.
//
//Network topology:
// 
//  Wifi 192.168.1.0
// 
// source          (sink)AP
//   *        *       *
//   |        |       |
//   n1       n2      n3 
//


using namespace ns3;

NS_LOG_COMPONENT_DEFINE ("SimpleWifiFrameAggregation");

//static uint32_t m_bytesTotal;
/*
static void
Throughput () // in Mbps calculated every 10s
{
  double mbps = (((m_bytesTotal * 8.0) / 1000000)/10);
  Time time = Simulator::Now ();
  m_bytesTotal = 0;

  Simulator::Schedule (Seconds (.1), &Throughput);
  std::cout << "Time "<< time.GetSeconds() << " Throughput "<< mbps <<"Mbps "<< std::endl;
  //std::cout << time.GetSeconds()<<"\t" << mbps << std::endl;
}

void
PhyRxOkTrace (std::string context, Ptr<const Packet> packet, double snr,
WifiMode mode, enum WifiPreamble preamble)
{
  Ptr<Packet> m_currentPacket;
  WifiMacHeader hdr;
  m_currentPacket = packet->Copy();
  m_currentPacket->RemoveHeader (hdr);

   if (hdr.IsData()){
        m_bytesTotal += m_currentPacket->GetSize ();
  }

}
*/

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

double m_referenceDistance = 1.0; // m
double m_exponent = 1.7;
double m_referenceLoss = 40.178882771; // L0 = 20 log(4 pi feqChann3 / 3 exp8)
double m_EnergyDet = -86.0;
double m_ccath = -99.0;
double m_txpower = 18.0; // dbm

  //LogComponentEnable ("EdcaTxopN", LOG_LEVEL_DEBUG);
  LogComponentEnable ("MsduAggregator", LOG_LEVEL_INFO);
  LogComponentEnable ("UdpEchoClientApplication", LOG_LEVEL_INFO);
  LogComponentEnable ("UdpEchoServerApplication", LOG_LEVEL_INFO);
  
  uint32_t nWifi = 1;
  CommandLine cmd;
  cmd.AddValue ("nWifi", "Number of wifi STA devices", nWifi);
  cmd.Parse (argc,argv);

  NodeContainer wifiApNode;
  wifiApNode.Create (1);
  NodeContainer wifiNodes;
  wifiNodes.Create (2);

  MobilityHelper mobility;
  mobility.SetPositionAllocator ("ns3::GridPositionAllocator",
    "MinX", DoubleValue (0.0),
    "MinY", DoubleValue (0.0),
    "DeltaX", DoubleValue (50.0),
    "DeltaY", DoubleValue (0.0),
    "GridWidth", UintegerValue (3),
    "LayoutType", StringValue ("RowFirst"));

  mobility.SetMobilityModel ("ns3::RandomWalk2dMobilityModel",
    "Bounds", RectangleValue (Rectangle (-50, 50, -50, 50)));
  mobility.Install (wifiNodes);

  mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");
  mobility.Install (wifiApNode);

  YansWifiChannelHelper channel = YansWifiChannelHelper::Default ();

channel.AddPropagationLoss ("ns3::LogDistancePropagationLossModel");

  YansWifiPhyHelper phy = YansWifiPhyHelper::Default ();


phy.Set ("EnergyDetectionThreshold", DoubleValue (m_EnergyDet)); //defulat val is -96dBm
phy.Set ("CcaMode1Threshold", DoubleValue (m_ccath)); //default val is -99dBm
phy.Set ("TxGain", DoubleValue (1.0)); // Use 5.0 to extend range to about 300 meters
phy.Set ("RxGain", DoubleValue (1.0)); // Use 5.0 to extend range to about 300 meters
phy.Set ("TxPowerLevels", UintegerValue (1) );
phy.Set ("TxPowerEnd", DoubleValue (m_txpower) ); //default val is 16.0206dBm
phy.Set ("TxPowerStart", DoubleValue (m_txpower) ); //default val is 16.0206dBm
phy.Set ("RxNoiseFigure", DoubleValue (7.0) ); //defulat val is 7dB


  phy.SetChannel (channel.Create ());

  WifiHelper wifi = WifiHelper::Default ();
  QosWifiMacHelper mac = QosWifiMacHelper::Default ();
  wifi.SetRemoteStationManager ("ns3::AarfWifiManager", "FragmentationThreshold", UintegerValue (4000));//2500

  Ssid ssid = Ssid ("ns-3-802.11n");
  mac.SetType ("ns3::QstaWifiMac", 
    "Ssid", SsidValue (ssid),
    "ActiveProbing", BooleanValue (false));
  mac.SetMsduAggregatorForAc (AC_BE, "ns3::MsduStandardAggregator", "MaxAmsduSize", UintegerValue (3839));
  
  NetDeviceContainer staDevices;
  staDevices = wifi.Install (phy, mac, wifiNodes);
  Config::Set ("/NodeList/0/DeviceList/0/Mac/BE_EdcaTxopN/BlockAckThreshold", UintegerValue (2));  
  Config::Set ("/NodeList/1/DeviceList/0/Mac/BE_EdcaTxopN/BlockAckThreshold", UintegerValue (2));


  mac.SetType ("ns3::QapWifiMac", 
    "Ssid", SsidValue (ssid));
  mac.SetMsduAggregatorForAc (AC_BE, "ns3::MsduStandardAggregator","MaxAmsduSize", UintegerValue (3839));//7935

  NetDeviceContainer apDevice;
  apDevice = wifi.Install (phy, mac, wifiApNode);
  Config::Set ("/NodeList/2/DeviceList/0/Mac/BE_EdcaTxopN/BlockAckThreshold", UintegerValue (2));


  
  /* Internet stack*/
  InternetStackHelper stack;
  stack.Install (wifiApNode);
  stack.Install (wifiNodes);

  Ipv4AddressHelper address;

  address.SetBase ("192.168.1.0", "255.255.255.0");
  Ipv4InterfaceContainer wifiNodesInterfaces;
  Ipv4InterfaceContainer apNodeInterface;
  
  wifiNodesInterfaces = address.Assign (staDevices);
  apNodeInterface = address.Assign (apDevice);
  
//Routing

Ipv4StaticRoutingHelper ipv4RoutingHelper;
Ptr<Ipv4> ipv4Node;
Ptr<Ipv4StaticRouting> staticRoutingNode;

//wifiNode 0
ipv4Node = wifiNodes.Get(0)->GetObject<Ipv4> ();
staticRoutingNode = ipv4RoutingHelper.GetStaticRouting (ipv4Node);
//left node
//staticRoutingNode->AddHostRouteTo (ipv4Interfaces.GetAddress (leftNodes), ipv4Interfaces.GetAddress (leftExit), 1);
//right node
//staticRoutingNode->AddHostRouteTo (apNodeInterface.GetAddress (0), apNodeInterface.GetAddress (0), 1);
staticRoutingNode->AddHostRouteTo (wifiNodesInterfaces.GetAddress (1), wifiNodesInterfaces.GetAddress (1), 1);

//wifiNode 0
ipv4Node = wifiNodes.Get(1)->GetObject<Ipv4> ();
staticRoutingNode = ipv4RoutingHelper.GetStaticRouting (ipv4Node);
//left node
staticRoutingNode->AddHostRouteTo (wifiNodesInterfaces.GetAddress (0), wifiNodesInterfaces.GetAddress (0), 1);
//right node
staticRoutingNode->AddHostRouteTo (apNodeInterface.GetAddress (0), apNodeInterface.GetAddress (0), 1);

//apNode 0
ipv4Node = wifiApNode.Get(0)->GetObject<Ipv4> ();
staticRoutingNode = ipv4RoutingHelper.GetStaticRouting (ipv4Node);
//left node
staticRoutingNode->AddHostRouteTo (wifiNodesInterfaces.GetAddress (1), wifiNodesInterfaces.GetAddress (1), 1);
//staticRoutingNode->AddHostRouteTo (wifiNodesInterfaces.GetAddress (0), wifiNodesInterfaces.GetAddress (0), 1);
//right node
//staticRoutingNode->AddHostRouteTo (apNodeInterface.GetAddress (0), apNodeInterface.GetAddress (0), 1);


  // Create a packet sink to receive these packets on n2...
  uint16_t port = 50000;
  PacketSinkHelper sink ("ns3::TcpSocketFactory",InetSocketAddress (Ipv4Address::GetAny (), port));
  ApplicationContainer apps = sink.Install (wifiApNode.Get (0));
  apps.Start (Seconds (1.0));
  apps.Stop (Seconds (7.0));//0.293092,3

  //create onoff application
  OnOffHelper onOffHelper ("ns3::TcpSocketFactory", InetSocketAddress ("192.168.1.3", port));
//  OnOffHelper onOffHelper ("ns3::TcpSocketFactory", InetSocketAddress ("10.0.0.3", port));
//  OnOffHelper onOffHelper ("ns3::TcpSocketFactory", InetSocketAddress ("10.0.0.4", port));
  onOffHelper.SetAttribute ("OnTime", RandomVariableValue (ConstantVariable (100)));
  onOffHelper.SetAttribute ("OffTime", RandomVariableValue (ConstantVariable (0)));
  onOffHelper.SetAttribute ("DataRate", DataRateValue (DataRate (1000000)));//3502654
  onOffHelper.SetAttribute ("PacketSize", UintegerValue (1000));
  //onOffHelper.SetAttribute ("maxBytes", UintegerValue (10000));
  ApplicationContainer source;

  source.Add (onOffHelper.Install (wifiNodes.Get(0)));
  source.Start (Seconds (1.1));
  source.Stop (Seconds (10.0));


 Simulator::Stop (Seconds (10.0));
  

  // 8. Install FlowMonitor on all nodes
  FlowMonitorHelper flowmon;
  Ptr<FlowMonitor> monitor = flowmon.InstallAll();
 
  Simulator::Run ();

  // 10. Print per flow 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);
      std::cout << "Flow " << i->first << " (" << t.sourceAddress << " -> " << t.destinationAddress << ")\n";
      std::cout << "  Tx Bytes:   " << i->second.txBytes << "\n";
      std::cout << "  Rx Bytes:   " << i->second.rxBytes << "\n";
      std::cout << "  Throughput: " << i->second.rxBytes * 8.0 / 10.0 / 1024 / 1024  << " Mbps\n";
    }

  Simulator::Destroy ();
  
  return 0;
}

[Mohammad Abu Shattal]

I think that the AddPropagationLoss function is additive, that means it adds the propagation loss to currently configured model "or default model ". so it increase the path loss and lessen the Rx power.
you can check doxygen for more info:
https://www.nsnam.org/doxygen/classns3_1_1_yans_wifi_channel_helper.html#a9a7fb65955fd9eb046600b89292e8062

I hope this is helpful ...

[Sebastien Deronne]

First of all, avoid copy-pasting your code as a text, you have a friendly "attach file" which is there for this purpose.

Second, providing code is a good thing, but what about traces?
People always post before investigating traces, this is quite irritating.
And if you got traces, then feel free to attach them as well.

And finally, in order to answer quickly to your question: propagation loss models are chained to each others.

As calling YansWifiChannelHelper::Default () already adds the default propagation loss model,
you then add a second propagation loss model (actually, the same as the default one, which has no sense) by doing this:

channel.AddPropagationLoss ("ns3::LogDistancePropagationLossModel");

So, either you do not call the Default() function and you add yourself your propagation loss model and your propagation delay model, or you keep the default propagation loss model and you tune its parameters as desired (as it seems you want to use LogDistancePropagationLossModel, which is indeed the default propagation loss model) .

[Miralem Mehic]

 
So, either you do not call the Default() function and you add yourself your propagation loss model and your propagation delay model, or you keep the default propagation loss model and you tune its parameters as desired (as it seems you want to use LogDistancePropagationLossModel, which is indeed the default propagation loss model) .

Hi Sebastian, 
can you please provide some instructions how to tune the paramteres of propagation loss?

For example, I would like to gradually increase the height of receiving anntena (HeightAboveZ) in TwoRayGroundPropagationLossModel

Can you please point me to some document or some tutorial for such modification. 

Thank you!