wifi: Add a ProbeDelay attribute to StaWifiMac

examples/wireless/examples-to-run.py

@@ -41,9 +41,9 @@ cpp_examples = [
     ("wifi-ht-network --simulationTime=0.2 --frequency=5 --useRts=0 --minExpectedThroughput=5 --maxExpectedThroughput=135", "True", "True"),
     ("wifi-ht-network --simulationTime=0.2 --frequency=5 --useRts=1 --minExpectedThroughput=5 --maxExpectedThroughput=131", "True", "True"),
     ("wifi-ht-network --simulationTime=0.2 --frequency=2.4 --useRts=0 --minExpectedThroughput=5 --maxExpectedThroughput=132", "True", "True"),
-    ("wifi-ht-network --simulationTime=0.2 --frequency=2.4 --useRts=1 --minExpectedThroughput=5 --maxExpectedThroughput=128", "True", "True"),
+    ("wifi-ht-network --simulationTime=0.2 --frequency=2.4 --useRts=1 --minExpectedThroughput=5 --maxExpectedThroughput=129", "True", "True"),
     ("wifi-vht-network --simulationTime=0.2 --useRts=0  --minExpectedThroughput=5 --maxExpectedThroughput=583", "True", "True"),
-    ("wifi-vht-network --simulationTime=0.2 --useRts=1  --minExpectedThroughput=5 --maxExpectedThroughput=543", "True", "True"),
+    ("wifi-vht-network --simulationTime=0.2 --useRts=1  --minExpectedThroughput=5 --maxExpectedThroughput=547", "True", "True"),
     ("wifi-he-network --simulationTime=0.25 --frequency=5 --useRts=0 --minExpectedThroughput=6 --maxExpectedThroughput=844", "True", "True"),
     ("wifi-he-network --simulationTime=0.3 --frequency=5 --useRts=0 --useExtendedBlockAck=1 --minExpectedThroughput=6 --maxExpectedThroughput=1033", "True", "True"),
     ("wifi-he-network --simulationTime=0.3 --frequency=5 --useRts=1 --minExpectedThroughput=6 --maxExpectedThroughput=745", "True", "True"),

examples/wireless/wifi-80211e-txop.cc

@@ -396,7 +396,7 @@ int main (int argc, char *argv[])
   throughput = totalPacketsThroughC * payloadSize * 8 / (simulationTime * 1000000.0);
   std::cout << "AC_VI with default TXOP limit (4.096ms): " << '\n'
             << "  Throughput = " << throughput << " Mbit/s" << '\n';
-  if (verifyResults && (throughput < 37.0 || throughput > 37.5))
+  if (verifyResults && (throughput < 36.5 || throughput > 37.5))
     {
       NS_LOG_ERROR ("Obtained throughput " << throughput << " is not in the expected boundaries!");
       exit (1);

examples/wireless/wifi-aggregation.cc

@@ -330,7 +330,7 @@ int main (int argc, char *argv[])
 
   double throughput = totalPacketsThroughA * payloadSize * 8 / (simulationTime * 1000000.0);
   std::cout << "Throughput with default configuration (A-MPDU aggregation enabled, 65kB): " << throughput << " Mbit/s" << '\n';
-  if (verifyResults && (throughput < 58.5 || throughput > 59.5))
+  if (verifyResults && (throughput < 59.0 || throughput > 60.0))
     {
       NS_LOG_ERROR ("Obtained throughput " << throughput << " is not in the expected boundaries!");
       exit (1);

examples/wireless/wifi-he-network.cc

@@ -261,7 +261,7 @@ int main (int argc, char *argv[])
 
               RngSeedManager::SetSeed (1);
               RngSeedManager::SetRun (1);
-              int64_t streamNumber = 100;
+              int64_t streamNumber = 150;
               streamNumber += wifi.AssignStreams (apDevice, streamNumber);
               streamNumber += wifi.AssignStreams (staDevices, streamNumber);
 

src/wifi/helper/wifi-helper.cc

@@ -22,6 +22,7 @@
 
 #include "ns3/wifi-net-device.h"
 #include "ns3/ap-wifi-mac.h"
+#include "ns3/sta-wifi-mac.h"
 #include "ns3/ampdu-subframe-header.h"
 #include "ns3/mobility-model.h"
 #include "ns3/log.h"
@@ -992,11 +993,15 @@ WifiHelper::AssignStreams (NetDeviceContainer c, int64_t stream)
               currentStream += bk_txop->AssignStreams (currentStream);
             }
 
-          //if an AP, handle any beacon jitter
-          Ptr<ApWifiMac> apmac = DynamicCast<ApWifiMac> (mac);
-          if (apmac)
+          // if an AP, handle any beacon jitter
+          if (auto apMac = DynamicCast<ApWifiMac> (mac); apMac)
             {
-              currentStream += apmac->AssignStreams (currentStream);
+              currentStream += apMac->AssignStreams (currentStream);
+            }
+          // if a STA, handle any probe request jitter
+          if (auto staMac = DynamicCast<StaWifiMac> (mac); staMac)
+            {
+              currentStream += staMac->AssignStreams (currentStream);
             }
         }
     }

src/wifi/model/sta-wifi-mac.cc

@@ -23,7 +23,10 @@
 
 #include "ns3/log.h"
 #include "ns3/packet.h"
+#include "ns3/pointer.h"
+#include "ns3/random-variable-stream.h"
 #include "ns3/simulator.h"
+#include "ns3/string.h"
 #include "qos-txop.h"
 #include "sta-wifi-mac.h"
 #include "wifi-phy.h"
@@ -73,6 +76,12 @@ StaWifiMac::GetTypeId (void)
                    BooleanValue (false),
                    MakeBooleanAccessor (&StaWifiMac::SetActiveProbing, &StaWifiMac::GetActiveProbing),
                    MakeBooleanChecker ())
+    .AddAttribute ("ProbeDelay",
+                   "Delay (in microseconds) to be used prior to transmitting a "
+                   "Probe frame during active scanning.",
+                   StringValue ("ns3::UniformRandomVariable[Min=50.0|Max=250.0]"),
+                   MakePointerAccessor (&StaWifiMac::m_probeDelay),
+                   MakePointerChecker<RandomVariableStream> ())
     .AddTraceSource ("Assoc", "Associated with an access point.",
                      MakeTraceSourceAccessor (&StaWifiMac::m_assocLogger),
                      "ns3::Mac48Address::TracedCallback")
@@ -114,6 +123,14 @@ StaWifiMac::~StaWifiMac ()
   NS_LOG_FUNCTION (this);
 }
 
+int64_t
+StaWifiMac::AssignStreams (int64_t stream)
+{
+  NS_LOG_FUNCTION (this << stream);
+  m_probeDelay->SetStream (stream);
+  return 1;
+}
+
 uint16_t
 StaWifiMac::GetAssociationId (void) const
 {

src/wifi/model/sta-wifi-mac.h

@@ -35,6 +35,8 @@ namespace ns3  {
 
 class SupportedRates;
 class CapabilityInformation;
+class RandomVariableStream;
+
 
 /**
  * \ingroup wifi
@@ -194,6 +196,17 @@ public:
 
   void NotifyChannelSwitching (void) override;
 
+  /**
+   * Assign a fixed random variable stream number to the random variables
+   * used by this model.  Return the number of streams (possibly zero) that
+   * have been assigned.
+   *
+   * \param stream first stream index to use
+   *
+   * \return the number of stream indices assigned by this model
+   */
+  int64_t AssignStreams (int64_t stream);
+
 private:
   /**
    * The current MAC state of the STA.
@@ -357,6 +370,8 @@ private:
   Time m_beaconWatchdogEnd;    ///< beacon watchdog end
   uint32_t m_maxMissedBeacons; ///< maximum missed beacons
   bool m_activeProbing;        ///< active probing
+  Ptr<RandomVariableStream> m_probeDelay;  ///< RandomVariable used to randomize the time
+                                           ///< of the first Probe Response on each channel
   std::vector<ApInfo> m_candidateAps; ///< list of candidate APs to associate to
   // Note: std::multiset<ApInfo> might be a candidate container to implement
   // this sorted list, but we are using a std::vector because we want to sort