wifi-simple-interference.cc

Go to the documentation of this file.

/*
 * Copyright (c) 2009 The Boeing Company
 *
 * 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
 *
 */
 
// This script configures three nodes on an 802.11b physical layer, with
// 802.11b NICs in adhoc mode.  There is a transmitter, receiver, and
// interferer.  The transmitter sends one packet to the receiver and
// the receiver receives it with a certain configurable RSS (by default,
// -80 dBm).  The interferer does not do carrier sense and also sends
// the packet to interfere with the primary packet.  The channel model
// is clear channel.
//
// Therefore, at the receiver, the reception looks like this:
//
//     ------------------time---------------->
//     t0
//
//     |------------------------------------|
//     |                                    |
//     | primary received frame (time t0)   |
//     |                                    |
//     |------------------------------------|
//
//
//         t1
//         |-----------------------------------|
//         |                                   |
//         |  interfering frame (time t1)      |
//         |                                   |
//         |-----------------------------------|
//
// The orientation is:
//     n2  ---------> n0 <---------- n1
//  interferer      receiver       transmitter
//
// The configurable parameters are:
//   - Prss (primary rss) (-80 dBm default)
//   - Irss (interfering rss) (-95 dBm default)
//   - delta (microseconds, (t1-t0), may be negative, default 0)
//   - PpacketSize (primary packet size) (bytes, default 1000)
//   - IpacketSize (interferer packet size) (bytes, default 1000)
//
// For instance, for this configuration, the interfering frame arrives
// at -90 dBm with a time offset of 3.2 microseconds:
//
// ./ns3 run "wifi-simple-interference --Irss=-90 --delta=3.2"
//
// Note that all ns-3 attributes (not just the ones exposed in the below
// script) can be changed at command line; see the documentation.
//
// This script can also be helpful to put the Wifi layer into verbose
// logging mode; this command will turn on all wifi logging:
//
// ./ns3 run "wifi-simple-interference --verbose=1"
//
// When you are done, you will notice a pcap trace file in your directory.
// If you have tcpdump installed, you can try this:
//
// tcpdump -r wifi-simple-interference-0-0.pcap -nn -tt
// reading from file wifi-simple-interference-0-0.pcap, link-type IEEE802_11_RADIO (802.11 plus BSD
// radio information header) 10.008704 10008704us tsft 1.0 Mb/s 2437 MHz (0x00c0) -80dB signal -98dB
// noise IP 10.1.1.2.49153 > 10.1.1.255.80: UDP, length 1000
//
// Next, try this command and look at the tcpdump-- you should see two packets
// that are no longer interfering:
// ./ns3 run "wifi-simple-interference --delta=30000"
 
#include "ns3/command-line.h"
#include "ns3/config.h"
#include "ns3/double.h"
#include "ns3/internet-stack-helper.h"
#include "ns3/log.h"
#include "ns3/mobility-helper.h"
#include "ns3/mobility-model.h"
#include "ns3/ssid.h"
#include "ns3/string.h"
#include "ns3/yans-wifi-channel.h"
#include "ns3/yans-wifi-helper.h"
 
using namespace ns3;
 
NS_LOG_COMPONENT_DEFINE("WifiSimpleInterference");
 
/**
 * Print a packer that has been received.
 *
 * \param socket The receiving socket.
 * \return a string with the packet details.
 */
static inline std::string
PrintReceivedPacket(Ptr<Socket> socket)
{
    Address addr;
 
    std::ostringstream oss;
 
    while (socket->Recv())
    {
        socket->GetSockName(addr);
        InetSocketAddress iaddr = InetSocketAddress::ConvertFrom(addr);
 
        oss << "Received one packet!  Socket: " << iaddr.GetIpv4() << " port: " << iaddr.GetPort();
    }
 
    return oss.str();
}
 
/**
 * Function called when a packet is received.
 *
 * \param socket The receiving socket.
 */
static void
ReceivePacket(Ptr<Socket> socket)
{
    NS_LOG_UNCOND(PrintReceivedPacket(socket));
}
 
/**
 * Generate traffic
 *
 * \param socket The seding socket.
 * \param pktSize The packet size.
 * \param pktCount The packet counter.
 * \param pktInterval The interval between two packets.
 */
static void
GenerateTraffic(Ptr<Socket> socket, uint32_t pktSize, uint32_t pktCount, Time pktInterval)
{
    if (pktCount > 0)
    {
        socket->Send(Create<Packet>(pktSize));
        Simulator::Schedule(pktInterval,
                            &GenerateTraffic,
                            socket,
                            pktSize,
                            pktCount - 1,
                            pktInterval);
    }
    else
    {
        socket->Close();
    }
}
 
int
main(int argc, char* argv[])
{
    std::string phyMode("DsssRate1Mbps");
    double Prss = -80;           // -dBm
    double Irss = -95;           // -dBm
    double delta = 0;            // microseconds
    uint32_t PpacketSize = 1000; // bytes
    uint32_t IpacketSize = 1000; // bytes
    bool verbose = false;
 
    // these are not command line arguments for this version
    uint32_t numPackets = 1;
    double interval = 1.0;       // seconds
    double startTime = 10.0;     // seconds
    double distanceToRx = 100.0; // meters
 
    double offset = 91; // This is a magic number used to set the
                        // transmit power, based on other configuration
    CommandLine cmd(__FILE__);
    cmd.AddValue("phyMode", "Wifi Phy mode", phyMode);
    cmd.AddValue("Prss", "Intended primary received signal strength (dBm)", Prss);
    cmd.AddValue("Irss", "Intended interfering received signal strength (dBm)", Irss);
    cmd.AddValue("delta", "time offset (microseconds) for interfering signal", delta);
    cmd.AddValue("PpacketSize", "size of application packet sent", PpacketSize);
    cmd.AddValue("IpacketSize", "size of interfering packet sent", IpacketSize);
    cmd.AddValue("verbose", "turn on all WifiNetDevice log components", verbose);
    cmd.Parse(argc, argv);
    // Convert to time object
    Time interPacketInterval = Seconds(interval);
 
    // Fix non-unicast data rate to be the same as that of unicast
    Config::SetDefault("ns3::WifiRemoteStationManager::NonUnicastMode", StringValue(phyMode));
 
    NodeContainer c;
    c.Create(3);
 
    // The below set of helpers will help us to put together the wifi NICs we want
    WifiHelper wifi;
    if (verbose)
    {
        WifiHelper::EnableLogComponents(); // Turn on all Wifi logging
    }
    wifi.SetStandard(WIFI_STANDARD_80211b);
 
    YansWifiPhyHelper wifiPhy;
 
    // ns-3 supports RadioTap and Prism tracing extensions for 802.11b
    wifiPhy.SetPcapDataLinkType(WifiPhyHelper::DLT_IEEE802_11_RADIO);
 
    YansWifiChannelHelper wifiChannel;
    wifiChannel.SetPropagationDelay("ns3::ConstantSpeedPropagationDelayModel");
    wifiChannel.AddPropagationLoss("ns3::LogDistancePropagationLossModel");
    wifiPhy.SetChannel(wifiChannel.Create());
 
    // Add a mac and disable rate control
    WifiMacHelper wifiMac;
    wifi.SetRemoteStationManager("ns3::ConstantRateWifiManager",
                                 "DataMode",
                                 StringValue(phyMode),
                                 "ControlMode",
                                 StringValue(phyMode));
    // Set it to adhoc mode
    wifiMac.SetType("ns3::AdhocWifiMac");
    NetDeviceContainer devices = wifi.Install(wifiPhy, wifiMac, c.Get(0));
    // This will disable these sending devices from detecting a signal
    // so that they do not backoff
    wifiPhy.Set("TxGain", DoubleValue(offset + Prss));
    devices.Add(wifi.Install(wifiPhy, wifiMac, c.Get(1)));
    wifiPhy.Set("TxGain", DoubleValue(offset + Irss));
    devices.Add(wifi.Install(wifiPhy, wifiMac, c.Get(2)));
 
    // Note that with FixedRssLossModel, the positions below are not
    // used for received signal strength.
    MobilityHelper mobility;
    Ptr<ListPositionAllocator> positionAlloc = CreateObject<ListPositionAllocator>();
    positionAlloc->Add(Vector(0.0, 0.0, 0.0));
    positionAlloc->Add(Vector(distanceToRx, 0.0, 0.0));
    positionAlloc->Add(Vector(-1 * distanceToRx, 0.0, 0.0));
    mobility.SetPositionAllocator(positionAlloc);
    mobility.SetMobilityModel("ns3::ConstantPositionMobilityModel");
    mobility.Install(c);
 
    InternetStackHelper internet;
    internet.Install(c);
 
    TypeId tid = TypeId::LookupByName("ns3::UdpSocketFactory");
    Ptr<Socket> recvSink = Socket::CreateSocket(c.Get(0), tid);
    InetSocketAddress local = InetSocketAddress(Ipv4Address("10.1.1.1"), 80);
    recvSink->Bind(local);
    recvSink->SetRecvCallback(MakeCallback(&ReceivePacket));
 
    Ptr<Socket> source = Socket::CreateSocket(c.Get(1), tid);
    InetSocketAddress remote = InetSocketAddress(Ipv4Address("255.255.255.255"), 80);
    source->SetAllowBroadcast(true);
    source->Connect(remote);
 
    // Interferer will send to a different port; we will not see a
    // "Received packet" message
    Ptr<Socket> interferer = Socket::CreateSocket(c.Get(2), tid);
    InetSocketAddress interferingAddr = InetSocketAddress(Ipv4Address("255.255.255.255"), 49000);
    interferer->SetAllowBroadcast(true);
    interferer->Connect(interferingAddr);
 
    // Tracing
    wifiPhy.EnablePcap("wifi-simple-interference", devices.Get(0));
 
    // Output what we are doing
    NS_LOG_UNCOND("Primary packet RSS=" << Prss << " dBm and interferer RSS=" << Irss
                                        << " dBm at time offset=" << delta << " ms");
 
    Simulator::ScheduleWithContext(source->GetNode()->GetId(),
                                   Seconds(startTime),
                                   &GenerateTraffic,
                                   source,
                                   PpacketSize,
                                   numPackets,
                                   interPacketInterval);
 
    Simulator::ScheduleWithContext(interferer->GetNode()->GetId(),
                                   Seconds(startTime + delta / 1000000.0),
                                   &GenerateTraffic,
                                   interferer,
                                   IpacketSize,
                                   numPackets,
                                   interPacketInterval);
 
    Simulator::Run();
    Simulator::Destroy();
 
    return 0;
}