text: /* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
  /*
   * Copyright (c) 2015 SEBASTIEN DERONNE
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation;
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   * Author: Sebastien Deronne <sebastien.deronne@gmail.com>
   */
  
  #include "ns3/command-line.h"
  #include "ns3/config.h"
  #include "ns3/uinteger.h"
  #include "ns3/boolean.h"
  #include "ns3/double.h"
  #include "ns3/string.h"
  #include "ns3/log.h"
  #include "ns3/yans-wifi-helper.h"
  #include "ns3/ssid.h"
  #include "ns3/mobility-helper.h"
  #include "ns3/internet-stack-helper.h"
  #include "ns3/ipv4-address-helper.h"
  #include "ns3/udp-client-server-helper.h"
  #include "ns3/packet-sink-helper.h"
  #include "ns3/on-off-helper.h"
  #include "ns3/ipv4-global-routing-helper.h"
  #include "ns3/packet-sink.h"
  #include "ns3/yans-wifi-channel.h"
  
  // This is a simple example in order to show how to configure an IEEE 802.11ac Wi-Fi network.
  //
  // It outputs the UDP or TCP goodput for every VHT MCS value, which depends on the MCS value (0 to 9, where 9 is
  // forbidden when the channel width is 20 MHz), the channel width (20, 40, 80 or 160 MHz) and the guard interval (long
  // or short). The PHY bitrate is constant over all the simulation run. The user can also specify the distance between
  // the access point and the station: the larger the distance the smaller the goodput.
  //
  // The simulation assumes a single station in an infrastructure network:
  //
  //  STA     AP
  //    *     *
  //    |     |
  //   n1     n2
  //
  //Packets in this simulation belong to BestEffort Access Class (AC_BE).
  
  using namespace ns3;
  
  NS_LOG_COMPONENT_DEFINE ("vht-wifi-network");
  
  int main (int argc, char *argv[])
  {
    bool udp = true;
    bool useRts = false;
    double simulationTime = 10; //seconds
    double distance = 1.0; //meters
    int mcs = -1; // -1 indicates an unset value
    double minExpectedThroughput = 0;
    double maxExpectedThroughput = 0;
  
    CommandLine cmd (__FILE__);
    cmd.AddValue ("distance", "Distance in meters between the station and the access point", distance);
    cmd.AddValue ("simulationTime", "Simulation time in seconds", simulationTime);
    cmd.AddValue ("udp", "UDP if set to 1, TCP otherwise", udp);
    cmd.AddValue ("useRts", "Enable/disable RTS/CTS", useRts);
    cmd.AddValue ("mcs", "if set, limit testing to a specific MCS (0-9)", mcs);
    cmd.AddValue ("minExpectedThroughput", "if set, simulation fails if the lowest throughput is below this value", minExpectedThroughput);
    cmd.AddValue ("maxExpectedThroughput", "if set, simulation fails if the highest throughput is above this value", maxExpectedThroughput);
    cmd.Parse (argc,argv);
  
    if (useRts)
      {
        Config::SetDefault ("ns3::WifiRemoteStationManager::RtsCtsThreshold", StringValue ("0"));
      }
  
    double prevThroughput [8];
    for (uint32_t l = 0; l < 8; l++)
      {
        prevThroughput[l] = 0;
      }
    std::cout << "MCS value" << "\t\t" << "Channel width" << "\t\t" << "short GI" << "\t\t" << "Throughput" << '\n';
    int minMcs = 0;
    int maxMcs = 9;
    if (mcs >= 0 && mcs <= 9)
      {
        minMcs = mcs;
        maxMcs = mcs;
      }
    for (int mcs = minMcs; mcs <= maxMcs; mcs++)
      {
        uint8_t index = 0;
        double previous = 0;
        for (int channelWidth = 20; channelWidth <= 160; )
          {
            if (mcs == 9 && channelWidth == 20)
              {
                channelWidth *= 2;
                continue;
              }
            for (int sgi = 0; sgi < 2; sgi++)
              {
                uint32_t payloadSize; //1500 byte IP packet
                if (udp)
                  {
                    payloadSize = 1472; //bytes
                  }
                else
                  {
                    payloadSize = 1448; //bytes
                    Config::SetDefault ("ns3::TcpSocket::SegmentSize", UintegerValue (payloadSize));
                  }
  
                NodeContainer wifiStaNode;
                wifiStaNode.Create (1);
                NodeContainer wifiApNode;
                wifiApNode.Create (1);
  
                YansWifiChannelHelper channel = YansWifiChannelHelper::Default ();
                YansWifiPhyHelper phy;
                phy.SetChannel (channel.Create ());
  
                WifiHelper wifi;
                wifi.SetStandard (WIFI_STANDARD_80211ac);
                WifiMacHelper mac;
  
                std::ostringstream oss;
                oss << "VhtMcs" << mcs;
                wifi.SetRemoteStationManager ("ns3::ConstantRateWifiManager","DataMode", StringValue (oss.str ()),
                                              "ControlMode", StringValue (oss.str ()));
  
                Ssid ssid = Ssid ("ns3-80211ac");
  
                mac.SetType ("ns3::StaWifiMac",
                             "Ssid", SsidValue (ssid));
                phy.Set ("ChannelWidth", UintegerValue (channelWidth));
  
                NetDeviceContainer staDevice;
                staDevice = wifi.Install (phy, mac, wifiStaNode);
  
                mac.SetType ("ns3::ApWifiMac",
                             "EnableBeaconJitter", BooleanValue (false),
                             "Ssid", SsidValue (ssid));
                phy.Set ("ChannelWidth", UintegerValue (channelWidth));
  
                NetDeviceContainer apDevice;
                apDevice = wifi.Install (phy, mac, wifiApNode);
  
                // Set guard interval
                Config::Set ("/NodeList/*/DeviceList/*/$ns3::WifiNetDevice/HtConfiguration/ShortGuardIntervalSupported", BooleanValue (sgi));
  
                // mobility.
                MobilityHelper mobility;
                Ptr<ListPositionAllocator> positionAlloc = CreateObject<ListPositionAllocator> ();
  
                positionAlloc->Add (Vector (0.0, 0.0, 0.0));
                positionAlloc->Add (Vector (distance, 0.0, 0.0));
                mobility.SetPositionAllocator (positionAlloc);
  
                mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");
  
                mobility.Install (wifiApNode);
                mobility.Install (wifiStaNode);
  
                /* Internet stack*/
                InternetStackHelper stack;
                stack.Install (wifiApNode);
                stack.Install (wifiStaNode);
  
                Ipv4AddressHelper address;
                address.SetBase ("192.168.1.0", "255.255.255.0");
                Ipv4InterfaceContainer staNodeInterface;
                Ipv4InterfaceContainer apNodeInterface;
  
                staNodeInterface = address.Assign (staDevice);
                apNodeInterface = address.Assign (apDevice);
  
                /* Setting applications */
                ApplicationContainer serverApp;
                if (udp)
                  {
                    //UDP flow
                    uint16_t port = 9;
                    UdpServerHelper server (port);
                    serverApp = server.Install (wifiStaNode.Get (0));
                    serverApp.Start (Seconds (0.0));
                    serverApp.Stop (Seconds (simulationTime + 1));
  
                    UdpClientHelper client (staNodeInterface.GetAddress (0), port);
                    client.SetAttribute ("MaxPackets", UintegerValue (4294967295u));
                    client.SetAttribute ("Interval", TimeValue (Time ("0.00002"))); //packets/s
                    client.SetAttribute ("PacketSize", UintegerValue (payloadSize));
                    ApplicationContainer clientApp = client.Install (wifiApNode.Get (0));
                    clientApp.Start (Seconds (1.0));
                    clientApp.Stop (Seconds (simulationTime + 1));
                  }
                else
                  {
                    //TCP flow
                    uint16_t port = 50000;
                    Address localAddress (InetSocketAddress (Ipv4Address::GetAny (), port));
                    PacketSinkHelper packetSinkHelper ("ns3::TcpSocketFactory", localAddress);
                    serverApp = packetSinkHelper.Install (wifiStaNode.Get (0));
                    serverApp.Start (Seconds (0.0));
                    serverApp.Stop (Seconds (simulationTime + 1));
  
                    OnOffHelper onoff ("ns3::TcpSocketFactory", Ipv4Address::GetAny ());
                    onoff.SetAttribute ("OnTime",  StringValue ("ns3::ConstantRandomVariable[Constant=1]"));
                    onoff.SetAttribute ("OffTime", StringValue ("ns3::ConstantRandomVariable[Constant=0]"));
                    onoff.SetAttribute ("PacketSize", UintegerValue (payloadSize));
                    onoff.SetAttribute ("DataRate", DataRateValue (1000000000)); //bit/s
                    AddressValue remoteAddress (InetSocketAddress (staNodeInterface.GetAddress (0), port));
                    onoff.SetAttribute ("Remote", remoteAddress);
                    ApplicationContainer clientApp = onoff.Install (wifiApNode.Get (0));
                    clientApp.Start (Seconds (1.0));
                    clientApp.Stop (Seconds (simulationTime + 1));
                  }
  
                Ipv4GlobalRoutingHelper::PopulateRoutingTables ();
  
                Simulator::Stop (Seconds (simulationTime + 1));
                Simulator::Run ();
  
                uint64_t rxBytes = 0;
                if (udp)
                  {
                    rxBytes = payloadSize * DynamicCast<UdpServer> (serverApp.Get (0))->GetReceived ();
                  }
                else
                  {
                    rxBytes = DynamicCast<PacketSink> (serverApp.Get (0))->GetTotalRx ();
                  }
                double throughput = (rxBytes * 8) / (simulationTime * 1000000.0); //Mbit/s
  
                Simulator::Destroy ();
  
                std::cout << mcs << "\t\t\t" << channelWidth << " MHz\t\t\t" << sgi << "\t\t\t" << throughput << " Mbit/s" << std::endl;
  
                //test first element
                if (mcs == 0 && channelWidth == 20 && sgi == 0)
                  {
                    if (throughput < minExpectedThroughput)
                      {
                        NS_LOG_ERROR ("Obtained throughput " << throughput << " is not expected!");
                        exit (1);
                      }
                  }
                //test last element
                if (mcs == 9 && channelWidth == 160 && sgi == 1)
                  {
                    if (maxExpectedThroughput > 0 && throughput > maxExpectedThroughput)
                      {
                        NS_LOG_ERROR ("Obtained throughput " << throughput << " is not expected!");
                        exit (1);
                      }
                  }
                //test previous throughput is smaller (for the same mcs)
                if (throughput > previous)
                  {
                    previous = throughput;
                  }
                else
                  {
                    NS_LOG_ERROR ("Obtained throughput " << throughput << " is not expected!");
                    exit (1);
                  }
                //test previous throughput is smaller (for the same channel width and GI)
                if (throughput > prevThroughput [index])
                  {
                    prevThroughput [index] = throughput;
                  }
                else
                  {
                    NS_LOG_ERROR ("Obtained throughput " << throughput << " is not expected!");
                    exit (1);
                  }
                index++;
              }
            channelWidth *= 2;
          }
      }
    return 0;
  }
  