wifi-spatial-reuse.cc

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/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2019 University of Washington
 *
 * 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: Sébastien Deronne <sebastien.deronne@gmail.com>
 */
 
//
//  This example program can be used to experiment with spatial
//  reuse mechanisms of 802.11ax.
//
//  The geometry is as follows:
//
//                STA1          STA1
//                 |              |
//              d1 |              |d2
//                 |       d3     |
//                AP1 -----------AP2
//
//  STA1 and AP1 are in one BSS (with color set to 1), while STA2 and AP2 are in
//  another BSS (with color set to 2). The distances are configurable (d1 through d3).
//
//  STA1 is continously transmitting data to AP1, while STA2 is continuously sending data to AP2.
//  Each STA has configurable traffic loads (inter packet interval and packet size).
//  It is also possible to configure TX power per node as well as their CCA-ED tresholds.
//  OBSS_PD spatial reuse feature can be enabled (default) or disabled, and the OBSS_PD
//  threshold can be set as well (default: -72 dBm).
//  A simple Friis path loss model is used and a constant PHY rate is considered.
//
//  In general, the program can be configured at run-time by passing command-line arguments.
//  The following command will display all of the available run-time help options:
//    ./ns3 run "wifi-spatial-reuse --help"
//
//  According to the Wi-Fi models of ns-3.36 release, throughput with
//  OBSS PD enabled (--enableObssPd=True) was roughly 6.5 Mbps, and with
//  it disabled (--enableObssPd=False) was roughly 3.5 Mbps.
//
//  This difference between those results is because OBSS_PD spatial
//  reuse enables to ignore transmissions from another BSS when the
//  received power is below the configured threshold, and therefore
//  either defer during ongoing transmission or transmit at the same
//  time.
//
//  Note that, by default, this script configures a network using a
//  channel bandwidth of 20 MHz. Changing this value alone (through
//  the --channelWidth argument) without properly adjusting other
//  parameters will void the effect of spatial reuse: since energy is
//  measured over the 20 MHz primary channel regardless of the channel
//  width, doubling the transmission bandwidth creates a 3 dB drop in
//  the measured energy level (i.e., a halving of the measured
//  energy). Because of this, when using the channelWidth argument
//  users should also adjust the CCA-ED Thresholds (via --ccaEdTrSta1,
//  --ccaEdTrSta2, --ccaEdTrAp1, and --ccaEdTrAp2), the Minimum RSSI
//  for preamble detection (via --minimumRssi), and the OBSS PD
//  Threshold (via --obssPdThreshold) appropriately. For instance,
//  this can be accomplished for a channel width of 40 MHz by lowering
//  all these values by 3 dB compared to their defaults.
//
//  In addition, consider that adapting the adjustments shown above
//  for an 80 MHz bandwidth (using a 6 dB threshold adjustment instead
//  of 3 dB) will not produce any changes when enableObssPd is enabled
//  or disabled. The cause for this is the insufficient amount of
//  traffic that is generated by default in the example: increasing
//  the bandwidth shortens the frame durations, and lowers the
//  collision probability. Collisions between BSSs are a necessary
//  condition to see the improvements brought by spatial reuse, and
//  thus increasing the amount of generated traffic by setting the
//  interval argument to a lower value is necessary to see the
//  benefits of spatial reuse in this scenario. This can, for
//  instance, be accomplished by setting --interval=0.0001.
//
 
#include "ns3/abort.h"
#include "ns3/command-line.h"
#include "ns3/config.h"
#include "ns3/string.h"
#include "ns3/double.h"
#include "ns3/spectrum-wifi-helper.h"
#include "ns3/ssid.h"
#include "ns3/mobility-helper.h"
#include "ns3/application-container.h"
#include "ns3/multi-model-spectrum-channel.h"
#include "ns3/wifi-net-device.h"
#include "ns3/ap-wifi-mac.h"
#include "ns3/he-configuration.h"
#include "ns3/packet-socket-helper.h"
#include "ns3/packet-socket-client.h"
#include "ns3/packet-socket-server.h"
 
using namespace ns3;
 
std::vector<uint32_t> bytesReceived (4);
 
uint32_t
ContextToNodeId (std::string context)
{
  std::string sub = context.substr (10);
  uint32_t pos = sub.find ("/Device");
  return atoi (sub.substr (0, pos).c_str ());
}
 
void
SocketRx (std::string context, Ptr<const Packet> p, const Address &addr)
{
  uint32_t nodeId = ContextToNodeId (context);
  bytesReceived[nodeId] += p->GetSize ();
}
 
int
main (int argc, char *argv[])
{
  double duration = 10.0; // seconds
  double d1 = 30.0; // meters
  double d2 = 30.0; // meters
  double d3 = 150.0; // meters
  double powSta1 = 10.0; // dBm
  double powSta2 = 10.0; // dBm
  double powAp1 = 21.0; // dBm
  double powAp2 = 21.0; // dBm
  double ccaEdTrSta1 = -62; // dBm
  double ccaEdTrSta2 = -62; // dBm
  double ccaEdTrAp1 = -62; // dBm
  double ccaEdTrAp2 = -62; // dBm
  double minimumRssi = -82; // dBm
  int channelBandwidth = 20; // MHz
  uint32_t payloadSize = 1500; // bytes
  uint32_t mcs = 0; // MCS value
  double interval = 0.001; // seconds
  bool enableObssPd = true;
  double obssPdThreshold = -72.0; // dBm
 
  CommandLine cmd (__FILE__);
  cmd.AddValue ("duration", "Duration of simulation (s)", duration);
  cmd.AddValue ("interval", "Inter packet interval (s)", interval);
  cmd.AddValue ("enableObssPd", "Enable/disable OBSS_PD", enableObssPd);
  cmd.AddValue ("d1", "Distance between STA1 and AP1 (m)", d1);
  cmd.AddValue ("d2", "Distance between STA2 and AP2 (m)", d2);
  cmd.AddValue ("d3", "Distance between AP1 and AP2 (m)", d3);
  cmd.AddValue ("powSta1", "Power of STA1 (dBm)", powSta1);
  cmd.AddValue ("powSta2", "Power of STA2 (dBm)", powSta2);
  cmd.AddValue ("powAp1", "Power of AP1 (dBm)", powAp1);
  cmd.AddValue ("powAp2", "Power of AP2 (dBm)", powAp2);
  cmd.AddValue ("ccaEdTrSta1", "CCA-ED Threshold of STA1 (dBm)", ccaEdTrSta1);
  cmd.AddValue ("ccaEdTrSta2", "CCA-ED Threshold of STA2 (dBm)", ccaEdTrSta2);
  cmd.AddValue ("ccaEdTrAp1", "CCA-ED Threshold of AP1 (dBm)", ccaEdTrAp1);
  cmd.AddValue ("ccaEdTrAp2", "CCA-ED Threshold of AP2 (dBm)", ccaEdTrAp2);
  cmd.AddValue ("minimumRssi", "Minimum RSSI for the ThresholdPreambleDetectionModel", minimumRssi);
  cmd.AddValue ("channelBandwidth", "Bandwidth of the channel in MHz [20, 40, or 80]", channelBandwidth);
  cmd.AddValue ("obssPdThreshold", "Threshold for the OBSS PD Algorithm", obssPdThreshold);
  cmd.AddValue ("mcs", "The constant MCS value to transmit HE PPDUs", mcs);
  cmd.Parse (argc, argv);
 
  NodeContainer wifiStaNodes;
  wifiStaNodes.Create (2);
 
  NodeContainer wifiApNodes;
  wifiApNodes.Create (2);
 
  SpectrumWifiPhyHelper spectrumPhy;
  Ptr<MultiModelSpectrumChannel> spectrumChannel = CreateObject<MultiModelSpectrumChannel> ();
  Ptr<FriisPropagationLossModel> lossModel = CreateObject<FriisPropagationLossModel> ();
  spectrumChannel->AddPropagationLossModel (lossModel);
  Ptr<ConstantSpeedPropagationDelayModel> delayModel = CreateObject<ConstantSpeedPropagationDelayModel> ();
  spectrumChannel->SetPropagationDelayModel (delayModel);
 
  spectrumPhy.SetChannel (spectrumChannel);
  spectrumPhy.SetErrorRateModel ("ns3::YansErrorRateModel");
  switch (channelBandwidth)
    {
    case 20:
      spectrumPhy.Set ("ChannelSettings", StringValue ("{36, 20, BAND_5GHZ, 0}"));
      break;
    case 40:
      spectrumPhy.Set ("ChannelSettings", StringValue ("{62, 40, BAND_5GHZ, 0}"));
      break;
    case 80:
      spectrumPhy.Set ("ChannelSettings", StringValue ("{171, 80, BAND_5GHZ, 0}"));
      break;
    default:
      NS_ABORT_MSG ("Unrecognized channel bandwidth: " << channelBandwidth);
      break;
    }
  spectrumPhy.SetPreambleDetectionModel ("ns3::ThresholdPreambleDetectionModel",
                                         "MinimumRssi", DoubleValue (minimumRssi));
 
  WifiHelper wifi;
  wifi.SetStandard (WIFI_STANDARD_80211ax);
  if (enableObssPd)
    {
      wifi.SetObssPdAlgorithm ("ns3::ConstantObssPdAlgorithm",
                               "ObssPdLevel", DoubleValue (obssPdThreshold));
    }
 
  WifiMacHelper mac;
  std::ostringstream oss;
  oss << "HeMcs" << mcs;
  wifi.SetRemoteStationManager ("ns3::ConstantRateWifiManager",
                                "DataMode", StringValue (oss.str ()),
                                "ControlMode", StringValue (oss.str ()));
 
  spectrumPhy.Set ("TxPowerStart", DoubleValue (powSta1));
  spectrumPhy.Set ("TxPowerEnd", DoubleValue (powSta1));
  spectrumPhy.Set ("CcaEdThreshold", DoubleValue (ccaEdTrSta1));
  spectrumPhy.Set ("RxSensitivity", DoubleValue (-92.0));
 
  Ssid ssidA = Ssid ("A");
  mac.SetType ("ns3::StaWifiMac",
               "Ssid", SsidValue (ssidA));
  NetDeviceContainer staDeviceA = wifi.Install (spectrumPhy, mac, wifiStaNodes.Get (0));
 
  spectrumPhy.Set ("TxPowerStart", DoubleValue (powAp1));
  spectrumPhy.Set ("TxPowerEnd", DoubleValue (powAp1));
  spectrumPhy.Set ("CcaEdThreshold", DoubleValue (ccaEdTrAp1));
  spectrumPhy.Set ("RxSensitivity", DoubleValue (-92.0));
 
  mac.SetType ("ns3::ApWifiMac",
               "Ssid", SsidValue (ssidA));
  NetDeviceContainer apDeviceA = wifi.Install (spectrumPhy, mac, wifiApNodes.Get (0));
 
  Ptr<WifiNetDevice> apDevice = apDeviceA.Get (0)->GetObject<WifiNetDevice> ();
  Ptr<ApWifiMac> apWifiMac = apDevice->GetMac ()->GetObject<ApWifiMac> ();
  if (enableObssPd)
    {
      apDevice->GetHeConfiguration ()->SetAttribute ("BssColor", UintegerValue (1));
    }
 
  spectrumPhy.Set ("TxPowerStart", DoubleValue (powSta2));
  spectrumPhy.Set ("TxPowerEnd", DoubleValue (powSta2));
  spectrumPhy.Set ("CcaEdThreshold", DoubleValue (ccaEdTrSta2));
  spectrumPhy.Set ("RxSensitivity", DoubleValue (-92.0));
 
  Ssid ssidB = Ssid ("B");
  mac.SetType ("ns3::StaWifiMac",
               "Ssid", SsidValue (ssidB));
  NetDeviceContainer staDeviceB = wifi.Install (spectrumPhy, mac, wifiStaNodes.Get (1));
 
  spectrumPhy.Set ("TxPowerStart", DoubleValue (powAp2));
  spectrumPhy.Set ("TxPowerEnd", DoubleValue (powAp2));
  spectrumPhy.Set ("CcaEdThreshold", DoubleValue (ccaEdTrAp2));
  spectrumPhy.Set ("RxSensitivity", DoubleValue (-92.0));
 
  mac.SetType ("ns3::ApWifiMac",
               "Ssid", SsidValue (ssidB));
  NetDeviceContainer apDeviceB = wifi.Install (spectrumPhy, mac, wifiApNodes.Get (1));
 
  Ptr<WifiNetDevice> ap2Device = apDeviceB.Get (0)->GetObject<WifiNetDevice> ();
  apWifiMac = ap2Device->GetMac ()->GetObject<ApWifiMac> ();
  if (enableObssPd)
    {
      ap2Device->GetHeConfiguration ()->SetAttribute ("BssColor", UintegerValue (2));
    }
 
  MobilityHelper mobility;
  Ptr<ListPositionAllocator> positionAlloc = CreateObject<ListPositionAllocator> ();
  positionAlloc->Add (Vector (0.0, 0.0, 0.0)); // AP1
  positionAlloc->Add (Vector (d3, 0.0, 0.0));  // AP2
  positionAlloc->Add (Vector (0.0, d1, 0.0));  // STA1
  positionAlloc->Add (Vector (d3, d2, 0.0));   // STA2
  mobility.SetMobilityModel ("ns3::ConstantPositionMobilityModel");
  mobility.SetPositionAllocator (positionAlloc);
  mobility.Install (wifiApNodes);
  mobility.Install (wifiStaNodes);
 
  PacketSocketHelper packetSocket;
  packetSocket.Install (wifiApNodes);
  packetSocket.Install (wifiStaNodes);
  ApplicationContainer apps;
  TypeId tid = TypeId::LookupByName ("ns3::UdpSocketFactory");
 
  //BSS 1
  {
    PacketSocketAddress socketAddr;
    socketAddr.SetSingleDevice (staDeviceA.Get (0)->GetIfIndex ());
    socketAddr.SetPhysicalAddress (apDeviceA.Get (0)->GetAddress ());
    socketAddr.SetProtocol (1);
    Ptr<PacketSocketClient> client = CreateObject<PacketSocketClient> ();
    client->SetRemote (socketAddr);
    wifiStaNodes.Get (0)->AddApplication (client);
    client->SetAttribute ("PacketSize", UintegerValue (payloadSize));
    client->SetAttribute ("MaxPackets", UintegerValue (0));
    client->SetAttribute ("Interval", TimeValue (Seconds (interval)));
    Ptr<PacketSocketServer> server = CreateObject<PacketSocketServer> ();
    server->SetLocal (socketAddr);
    wifiApNodes.Get (0)->AddApplication (server);
  }
 
  // BSS 2
  {
    PacketSocketAddress socketAddr;
    socketAddr.SetSingleDevice (staDeviceB.Get (0)->GetIfIndex ());
    socketAddr.SetPhysicalAddress (apDeviceB.Get (0)->GetAddress ());
    socketAddr.SetProtocol (1);
    Ptr<PacketSocketClient> client = CreateObject<PacketSocketClient> ();
    client->SetRemote (socketAddr);
    wifiStaNodes.Get (1)->AddApplication (client);
    client->SetAttribute ("PacketSize", UintegerValue (payloadSize));
    client->SetAttribute ("MaxPackets", UintegerValue (0));
    client->SetAttribute ("Interval", TimeValue (Seconds (interval)));
    Ptr<PacketSocketServer> server = CreateObject<PacketSocketServer> ();
    server->SetLocal (socketAddr);
    wifiApNodes.Get (1)->AddApplication (server);
  }
 
  Config::Connect ("/NodeList/*/ApplicationList/*/$ns3::PacketSocketServer/Rx", MakeCallback (&SocketRx));
 
  Simulator::Stop (Seconds (duration));
  Simulator::Run ();
 
  Simulator::Destroy ();
 
  for (uint32_t i = 0; i < 2; i++)
    {
      double throughput = static_cast<double> (bytesReceived[2 + i]) * 8 / 1000 / 1000 / duration;
      std::cout << "Throughput for BSS " << i + 1 << ": " << throughput << " Mbit/s" << std::endl;
    }
 
  return 0;
}