From 7ae478396bc0541792d568d2c8a9f737cc17b710 Mon Sep 17 00:00:00 2001
From: Nicola Baldo <nicola@baldo.biz>
Date: Mon, 9 May 2011 22:03:43 +0200
Subject: [PATCH] wifi tx duration calculations moved from InterferenceHelper
 to WifiPhy

---
 CHANGES.html                                  |  10 +
 src/wifi/model/interference-helper.cc         | 211 +-----------------
 src/wifi/model/interference-helper.h          |   5 -
 src/wifi/model/wifi-phy.cc                    | 207 +++++++++++++++++
 src/wifi/model/wifi-phy.h                     |  38 +++-
 src/wifi/model/yans-wifi-phy.cc               |   6 -
 src/wifi/model/yans-wifi-phy.h                |   1 -
 ...x-duration-test.cc => tx-duration-test.cc} |  24 +-
 src/wifi/wscript                              |   2 +-
 9 files changed, 269 insertions(+), 235 deletions(-)
 rename src/wifi/test/{interference-helper-tx-duration-test.cc => tx-duration-test.cc} (89%)

diff --git a/CHANGES.html b/CHANGES.html
index cec78f518..b0b02084c 100644
--- a/CHANGES.html
+++ b/CHANGES.html
@@ -83,6 +83,16 @@ objects. The implementation of <b>int64x64_t</b> is based on the previously-exis
 
 <h2>Changes to existing API:</h2>
 <ul>
+<li><b>Wifi TX duration calculation moved from InterferenceHelper to WifiPhy</b>
+<p>The following static methods have been moved from the InterferenceHelper class to the WifiPhy class:
+   <pre>
+static Time CalculateTxDuration (uint32_t size, WifiMode payloadMode, enum WifiPreamble preamble);
+static WifiMode GetPlcpHeaderMode (WifiMode payloadMode, WifiPreamble preamble);
+static uint32_t GetPlcpHeaderDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble);
+static uint32_t GetPlcpPreambleDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble);
+static uint32_t GetPayloadDurationMicroSeconds (uint32_t size, WifiMode payloadMode);
+</pre>
+</p></li>
 <li><b>Test cases no longer return a boolean value</b>
 <p>Unit test case DoRun() functions no longer return a bool value.  Now, they don't return a value at all.  The motivation for this change was to disallow users from merely returning "true" from a test case to force an error to be recorded.  Instead, test case macros should be used.
 </p></li>
diff --git a/src/wifi/model/interference-helper.cc b/src/wifi/model/interference-helper.cc
index e1393d6cd..d998e314d 100644
--- a/src/wifi/model/interference-helper.cc
+++ b/src/wifi/model/interference-helper.cc
@@ -189,211 +189,6 @@ InterferenceHelper::GetEnergyDuration (double energyW)
   return end > now ? end - now : MicroSeconds (0);
 }
 
-WifiMode
-InterferenceHelper::GetPlcpHeaderMode (WifiMode payloadMode, WifiPreamble preamble)
-{
-  switch (payloadMode.GetModulationClass ())
-    {
-    case WIFI_MOD_CLASS_OFDM:
-      {
-        switch (payloadMode.GetBandwidth ())
-          {
-          case 5000000:
-            return WifiPhy::GetOfdmRate1_5MbpsBW5MHz ();
-          case 10000000:
-            return WifiPhy::GetOfdmRate3MbpsBW10MHz ();
-          default:
-            // IEEE Std 802.11-2007, 17.3.2
-            // actually this is only the first part of the PlcpHeader,
-            // because the last 16 bits of the PlcpHeader are using the
-            // same mode of the payload
-            return WifiPhy::GetOfdmRate6Mbps ();
-          }
-      }
-
-    case WIFI_MOD_CLASS_ERP_OFDM:
-      return WifiPhy::GetErpOfdmRate6Mbps ();
-
-    case WIFI_MOD_CLASS_DSSS:
-      if (preamble == WIFI_PREAMBLE_LONG)
-        {
-          // IEEE Std 802.11-2007, sections 15.2.3 and 18.2.2.1
-          return WifiPhy::GetDsssRate1Mbps ();
-        }
-      else  //  WIFI_PREAMBLE_SHORT
-        {
-          // IEEE Std 802.11-2007, section 18.2.2.2
-          return WifiPhy::GetDsssRate2Mbps ();
-        }
-
-    default:
-      NS_FATAL_ERROR ("unsupported modulation class");
-      return WifiMode ();
-    }
-}
-
-uint32_t
-InterferenceHelper::GetPlcpHeaderDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble)
-{
-  switch (payloadMode.GetModulationClass ())
-    {
-    case WIFI_MOD_CLASS_OFDM:
-      {
-        switch (payloadMode.GetBandwidth ())
-          {
-          case 20000000:
-          default:
-            // IEEE Std 802.11-2007, section 17.3.3 and figure 17-4
-            // also section 17.3.2.3, table 17-4
-            // We return the duration of the SIGNAL field only, since the
-            // SERVICE field (which strictly speaking belongs to the PLCP
-            // header, see section 17.3.2 and figure 17-1) is sent using the
-            // payload mode.
-            return 4;
-          case 10000000:
-            // IEEE Std 802.11-2007, section 17.3.2.3, table 17-4
-            return 8;
-          case 5000000:
-            // IEEE Std 802.11-2007, section 17.3.2.3, table 17-4
-            return 16;
-          }
-      }
-
-    case WIFI_MOD_CLASS_ERP_OFDM:
-      return 16;
-
-    case WIFI_MOD_CLASS_DSSS:
-      if (preamble == WIFI_PREAMBLE_SHORT)
-        {
-          // IEEE Std 802.11-2007, section 18.2.2.2 and figure 18-2
-          return 24;
-        }
-      else // WIFI_PREAMBLE_LONG
-        {
-          // IEEE Std 802.11-2007, sections 18.2.2.1 and figure 18-1
-          return 48;
-        }
-
-    default:
-      NS_FATAL_ERROR ("unsupported modulation class");
-      return 0;
-    }
-}
-
-uint32_t
-InterferenceHelper::GetPlcpPreambleDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble)
-{
-  switch (payloadMode.GetModulationClass ())
-    {
-    case WIFI_MOD_CLASS_OFDM:
-      {
-        switch (payloadMode.GetBandwidth ())
-          {
-          case 20000000:
-          default:
-            // IEEE Std 802.11-2007, section 17.3.3,  figure 17-4
-            // also section 17.3.2.3, table 17-4
-            return 16;
-          case 10000000:
-            // IEEE Std 802.11-2007, section 17.3.3, table 17-4
-            // also section 17.3.2.3, table 17-4
-            return 32;
-          case 5000000:
-            // IEEE Std 802.11-2007, section 17.3.3
-            // also section 17.3.2.3, table 17-4
-            return 64;
-          }
-      }
-
-    case WIFI_MOD_CLASS_ERP_OFDM:
-      return 4;
-
-    case WIFI_MOD_CLASS_DSSS:
-      if (preamble == WIFI_PREAMBLE_SHORT)
-        {
-          // IEEE Std 802.11-2007, section 18.2.2.2 and figure 18-2
-          return 72;
-        }
-      else // WIFI_PREAMBLE_LONG
-        {
-          // IEEE Std 802.11-2007, sections 18.2.2.1 and figure 18-1
-          return 144;
-        }
-
-    default:
-      NS_FATAL_ERROR ("unsupported modulation class");
-      return 0;
-    }
-}
-
-uint32_t
-InterferenceHelper::GetPayloadDurationMicroSeconds (uint32_t size, WifiMode payloadMode)
-{
-  NS_LOG_FUNCTION (size << payloadMode);
-
-  switch (payloadMode.GetModulationClass ())
-    {
-    case WIFI_MOD_CLASS_OFDM:
-    case WIFI_MOD_CLASS_ERP_OFDM:
-      {
-        // IEEE Std 802.11-2007, section 17.3.2.3, table 17-4
-        // corresponds to T_{SYM} in the table
-        uint32_t symbolDurationUs;
-
-        switch (payloadMode.GetBandwidth ())
-          {
-          case 20000000:
-          default:
-            symbolDurationUs = 4;
-            break;
-          case 10000000:
-            symbolDurationUs = 8;
-            break;
-          case 5000000:
-            symbolDurationUs = 16;
-            break;
-          }
-
-        // IEEE Std 802.11-2007, section 17.3.2.2, table 17-3
-        // corresponds to N_{DBPS} in the table
-        double numDataBitsPerSymbol = payloadMode.GetDataRate ()  * symbolDurationUs / 1e6;
-
-        // IEEE Std 802.11-2007, section 17.3.5.3, equation (17-11)
-        uint32_t numSymbols = lrint (ceil ((16 + size * 8.0 + 6.0) / numDataBitsPerSymbol));
-
-        // Add signal extension for ERP PHY
-        if (payloadMode.GetModulationClass () == WIFI_MOD_CLASS_ERP_OFDM)
-          {
-            return numSymbols * symbolDurationUs + 6;
-          }
-        else
-          {
-            return numSymbols * symbolDurationUs;
-          }
-      }
-
-    case WIFI_MOD_CLASS_DSSS:
-      // IEEE Std 802.11-2007, section 18.2.3.5
-      NS_LOG_LOGIC (" size=" << size
-                             << " mode=" << payloadMode
-                             << " rate=" << payloadMode.GetDataRate () );
-      return lrint (ceil ((size * 8.0) / (payloadMode.GetDataRate () / 1.0e6)));
-
-    default:
-      NS_FATAL_ERROR ("unsupported modulation class");
-      return 0;
-    }
-}
-
-Time
-InterferenceHelper::CalculateTxDuration (uint32_t size, WifiMode payloadMode, WifiPreamble preamble)
-{
-  uint32_t duration = GetPlcpPreambleDurationMicroSeconds (payloadMode, preamble)
-    + GetPlcpHeaderDurationMicroSeconds (payloadMode, preamble)
-    + GetPayloadDurationMicroSeconds (size, payloadMode);
-  return MicroSeconds (duration);
-}
-
 void
 InterferenceHelper::AppendEvent (Ptr<InterferenceHelper::Event> event)
 {
@@ -470,9 +265,9 @@ InterferenceHelper::CalculatePer (Ptr<const InterferenceHelper::Event> event, Ni
   Time previous = (*j).GetTime ();
   WifiMode payloadMode = event->GetPayloadMode ();
   WifiPreamble preamble = event->GetPreambleType ();
-  WifiMode headerMode = GetPlcpHeaderMode (payloadMode, preamble);
-  Time plcpHeaderStart = (*j).GetTime () + MicroSeconds (GetPlcpPreambleDurationMicroSeconds (payloadMode, preamble));
-  Time plcpPayloadStart = plcpHeaderStart + MicroSeconds (GetPlcpHeaderDurationMicroSeconds (payloadMode, preamble));
+  WifiMode headerMode = WifiPhy::GetPlcpHeaderMode (payloadMode, preamble);
+  Time plcpHeaderStart = (*j).GetTime () + MicroSeconds (WifiPhy::GetPlcpPreambleDurationMicroSeconds (payloadMode, preamble));
+  Time plcpPayloadStart = plcpHeaderStart + MicroSeconds (WifiPhy::GetPlcpHeaderDurationMicroSeconds (payloadMode, preamble));
   double noiseInterferenceW = (*j).GetDelta ();
   double powerW = event->GetRxPowerW ();
 
diff --git a/src/wifi/model/interference-helper.h b/src/wifi/model/interference-helper.h
index 12aacd608..df83090a2 100644
--- a/src/wifi/model/interference-helper.h
+++ b/src/wifi/model/interference-helper.h
@@ -88,11 +88,6 @@ private:
   Time GetEnergyDuration (double energyW);
 
 
-  static WifiMode GetPlcpHeaderMode (WifiMode payloadMode, WifiPreamble preamble);
-  static uint32_t GetPlcpHeaderDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble);
-  static uint32_t GetPlcpPreambleDurationMicroSeconds (WifiMode mode, WifiPreamble preamble);
-  static uint32_t GetPayloadDurationMicroSeconds (uint32_t size, WifiMode payloadMode);
-  static Time CalculateTxDuration (uint32_t size, WifiMode payloadMode, WifiPreamble preamble);
   Ptr<InterferenceHelper::Event> Add (uint32_t size, WifiMode payloadMode,
                                       enum WifiPreamble preamble,
                                       Time duration, double rxPower);
diff --git a/src/wifi/model/wifi-phy.cc b/src/wifi/model/wifi-phy.cc
index 6f39e76e9..db2c19814 100644
--- a/src/wifi/model/wifi-phy.cc
+++ b/src/wifi/model/wifi-phy.cc
@@ -94,6 +94,213 @@ WifiPhy::~WifiPhy ()
   NS_LOG_FUNCTION (this);
 }
 
+
+WifiMode
+WifiPhy::GetPlcpHeaderMode (WifiMode payloadMode, WifiPreamble preamble)
+{
+  switch (payloadMode.GetModulationClass ())
+    {
+    case WIFI_MOD_CLASS_OFDM:
+      {
+        switch (payloadMode.GetBandwidth ())
+          {
+          case 5000000:
+            return WifiPhy::GetOfdmRate1_5MbpsBW5MHz ();
+          case 10000000:
+            return WifiPhy::GetOfdmRate3MbpsBW10MHz ();
+          default:
+            // IEEE Std 802.11-2007, 17.3.2
+            // actually this is only the first part of the PlcpHeader,
+            // because the last 16 bits of the PlcpHeader are using the
+            // same mode of the payload
+            return WifiPhy::GetOfdmRate6Mbps ();
+          }
+      }
+
+    case WIFI_MOD_CLASS_ERP_OFDM:
+      return WifiPhy::GetErpOfdmRate6Mbps ();
+
+    case WIFI_MOD_CLASS_DSSS:
+      if (preamble == WIFI_PREAMBLE_LONG)
+        {
+          // IEEE Std 802.11-2007, sections 15.2.3 and 18.2.2.1
+          return WifiPhy::GetDsssRate1Mbps ();
+        }
+      else  //  WIFI_PREAMBLE_SHORT
+        {
+          // IEEE Std 802.11-2007, section 18.2.2.2
+          return WifiPhy::GetDsssRate2Mbps ();
+        }
+
+    default:
+      NS_FATAL_ERROR ("unsupported modulation class");
+      return WifiMode ();
+    }
+}
+
+uint32_t
+WifiPhy::GetPlcpHeaderDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble)
+{
+  switch (payloadMode.GetModulationClass ())
+    {
+    case WIFI_MOD_CLASS_OFDM:
+      {
+        switch (payloadMode.GetBandwidth ())
+          {
+          case 20000000:
+          default:
+            // IEEE Std 802.11-2007, section 17.3.3 and figure 17-4
+            // also section 17.3.2.3, table 17-4
+            // We return the duration of the SIGNAL field only, since the
+            // SERVICE field (which strictly speaking belongs to the PLCP
+            // header, see section 17.3.2 and figure 17-1) is sent using the
+            // payload mode.
+            return 4;
+          case 10000000:
+            // IEEE Std 802.11-2007, section 17.3.2.3, table 17-4
+            return 8;
+          case 5000000:
+            // IEEE Std 802.11-2007, section 17.3.2.3, table 17-4
+            return 16;
+          }
+      }
+
+    case WIFI_MOD_CLASS_ERP_OFDM:
+      return 16;
+
+    case WIFI_MOD_CLASS_DSSS:
+      if (preamble == WIFI_PREAMBLE_SHORT)
+        {
+          // IEEE Std 802.11-2007, section 18.2.2.2 and figure 18-2
+          return 24;
+        }
+      else // WIFI_PREAMBLE_LONG
+        {
+          // IEEE Std 802.11-2007, sections 18.2.2.1 and figure 18-1
+          return 48;
+        }
+
+    default:
+      NS_FATAL_ERROR ("unsupported modulation class");
+      return 0;
+    }
+}
+
+uint32_t
+WifiPhy::GetPlcpPreambleDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble)
+{
+  switch (payloadMode.GetModulationClass ())
+    {
+    case WIFI_MOD_CLASS_OFDM:
+      {
+        switch (payloadMode.GetBandwidth ())
+          {
+          case 20000000:
+          default:
+            // IEEE Std 802.11-2007, section 17.3.3,  figure 17-4
+            // also section 17.3.2.3, table 17-4
+            return 16;
+          case 10000000:
+            // IEEE Std 802.11-2007, section 17.3.3, table 17-4
+            // also section 17.3.2.3, table 17-4
+            return 32;
+          case 5000000:
+            // IEEE Std 802.11-2007, section 17.3.3
+            // also section 17.3.2.3, table 17-4
+            return 64;
+          }
+      }
+
+    case WIFI_MOD_CLASS_ERP_OFDM:
+      return 4;
+
+    case WIFI_MOD_CLASS_DSSS:
+      if (preamble == WIFI_PREAMBLE_SHORT)
+        {
+          // IEEE Std 802.11-2007, section 18.2.2.2 and figure 18-2
+          return 72;
+        }
+      else // WIFI_PREAMBLE_LONG
+        {
+          // IEEE Std 802.11-2007, sections 18.2.2.1 and figure 18-1
+          return 144;
+        }
+
+    default:
+      NS_FATAL_ERROR ("unsupported modulation class");
+      return 0;
+    }
+}
+
+uint32_t
+WifiPhy::GetPayloadDurationMicroSeconds (uint32_t size, WifiMode payloadMode)
+{
+  NS_LOG_FUNCTION (size << payloadMode);
+
+  switch (payloadMode.GetModulationClass ())
+    {
+    case WIFI_MOD_CLASS_OFDM:
+    case WIFI_MOD_CLASS_ERP_OFDM:
+      {
+        // IEEE Std 802.11-2007, section 17.3.2.3, table 17-4
+        // corresponds to T_{SYM} in the table
+        uint32_t symbolDurationUs;
+
+        switch (payloadMode.GetBandwidth ())
+          {
+          case 20000000:
+          default:
+            symbolDurationUs = 4;
+            break;
+          case 10000000:
+            symbolDurationUs = 8;
+            break;
+          case 5000000:
+            symbolDurationUs = 16;
+            break;
+          }
+
+        // IEEE Std 802.11-2007, section 17.3.2.2, table 17-3
+        // corresponds to N_{DBPS} in the table
+        double numDataBitsPerSymbol = payloadMode.GetDataRate ()  * symbolDurationUs / 1e6;
+
+        // IEEE Std 802.11-2007, section 17.3.5.3, equation (17-11)
+        uint32_t numSymbols = lrint (ceil ((16 + size * 8.0 + 6.0) / numDataBitsPerSymbol));
+
+        // Add signal extension for ERP PHY
+        if (payloadMode.GetModulationClass () == WIFI_MOD_CLASS_ERP_OFDM)
+          {
+            return numSymbols * symbolDurationUs + 6;
+          }
+        else
+          {
+            return numSymbols * symbolDurationUs;
+          }
+      }
+
+    case WIFI_MOD_CLASS_DSSS:
+      // IEEE Std 802.11-2007, section 18.2.3.5
+      NS_LOG_LOGIC (" size=" << size
+                             << " mode=" << payloadMode
+                             << " rate=" << payloadMode.GetDataRate () );
+      return lrint (ceil ((size * 8.0) / (payloadMode.GetDataRate () / 1.0e6)));
+
+    default:
+      NS_FATAL_ERROR ("unsupported modulation class");
+      return 0;
+    }
+}
+
+Time
+WifiPhy::CalculateTxDuration (uint32_t size, WifiMode payloadMode, WifiPreamble preamble)
+{
+  uint32_t duration = GetPlcpPreambleDurationMicroSeconds (payloadMode, preamble)
+    + GetPlcpHeaderDurationMicroSeconds (payloadMode, preamble)
+    + GetPayloadDurationMicroSeconds (size, payloadMode);
+  return MicroSeconds (duration);
+}
+
+
 void
 WifiPhy::NotifyTxBegin (Ptr<const Packet> packet)
 {
diff --git a/src/wifi/model/wifi-phy.h b/src/wifi/model/wifi-phy.h
index 90ca441f7..8763bfab9 100644
--- a/src/wifi/model/wifi-phy.h
+++ b/src/wifi/model/wifi-phy.h
@@ -239,10 +239,44 @@ public:
    * \param size the number of bytes in the packet to send
    * \param payloadMode the transmission mode to use for this packet
    * \param preamble the type of preamble to use for this packet.
-   * \returns the total amount of time this PHY will stay busy for
+   * \return the total amount of time this PHY will stay busy for
    *          the transmission of these bytes.
    */
-  virtual Time CalculateTxDuration (uint32_t size, WifiMode payloadMode, enum WifiPreamble preamble) const = 0;
+  static Time CalculateTxDuration (uint32_t size, WifiMode payloadMode, enum WifiPreamble preamble);
+
+  /** 
+   * \param payloadMode the WifiMode use for the transmission of the payload
+   * \param preamble the type of preamble
+   * 
+   * \return the WifiMode used for the transmission of the PLCP header 
+   */
+  static WifiMode GetPlcpHeaderMode (WifiMode payloadMode, WifiPreamble preamble);
+
+  /** 
+   * 
+   * 
+   * \param payloadMode the WifiMode use for the transmission of the payload
+   * \param preamble the type of preamble 
+   * 
+   * \return the duration of the PLCP header in microseconds
+   */
+  static uint32_t GetPlcpHeaderDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble);
+
+  /** 
+   * \param payloadMode the WifiMode use for the transmission of the payload
+   * \param preamble the type of preamble 
+   * 
+   * \return the duration of the PLCP preamble in microseconds
+   */
+  static uint32_t GetPlcpPreambleDurationMicroSeconds (WifiMode payloadMode, WifiPreamble preamble);
+
+  /** 
+   * \param payloadMode the WifiMode use for the transmission of the payload
+   * \param preamble the type of preamble 
+   * 
+   * \return the duration of the payload in microseconds
+   */
+  static uint32_t GetPayloadDurationMicroSeconds (uint32_t size, WifiMode payloadMode);
 
   /**
    * The WifiPhy::GetNModes() and WifiPhy::GetMode() methods are used
diff --git a/src/wifi/model/yans-wifi-phy.cc b/src/wifi/model/yans-wifi-phy.cc
index a02756f2f..32a87176a 100644
--- a/src/wifi/model/yans-wifi-phy.cc
+++ b/src/wifi/model/yans-wifi-phy.cc
@@ -717,12 +717,6 @@ YansWifiPhy::GetLastRxStartTime (void) const
   return m_state->GetLastRxStartTime ();
 }
 
-Time
-YansWifiPhy::CalculateTxDuration (uint32_t size, WifiMode payloadMode, enum WifiPreamble preamble) const
-{
-  return m_interference.CalculateTxDuration (size, payloadMode, preamble);
-}
-
 double
 YansWifiPhy::DbToRatio (double dB) const
 {
diff --git a/src/wifi/model/yans-wifi-phy.h b/src/wifi/model/yans-wifi-phy.h
index 1e6a17a97..ccbad43ef 100644
--- a/src/wifi/model/yans-wifi-phy.h
+++ b/src/wifi/model/yans-wifi-phy.h
@@ -135,7 +135,6 @@ public:
   virtual Time GetStateDuration (void);
   virtual Time GetDelayUntilIdle (void);
   virtual Time GetLastRxStartTime (void) const;
-  virtual Time CalculateTxDuration (uint32_t size, WifiMode payloadMode, enum WifiPreamble preamble) const;
   virtual uint32_t GetNModes (void) const;
   virtual WifiMode GetMode (uint32_t mode) const;
   virtual double CalculateSnr (WifiMode txMode, double ber) const;
diff --git a/src/wifi/test/interference-helper-tx-duration-test.cc b/src/wifi/test/tx-duration-test.cc
similarity index 89%
rename from src/wifi/test/interference-helper-tx-duration-test.cc
rename to src/wifi/test/tx-duration-test.cc
index 709686de6..ff793d81e 100644
--- a/src/wifi/test/interference-helper-tx-duration-test.cc
+++ b/src/wifi/test/tx-duration-test.cc
@@ -29,11 +29,11 @@ NS_LOG_COMPONENT_DEFINE ("InterferenceHelperTxDurationTest");
 
 namespace ns3 {
 
-class InterferenceHelperTxDurationTest : public TestCase
+class TxDurationTest : public TestCase
 {
 public:
-  InterferenceHelperTxDurationTest ();
-  virtual ~InterferenceHelperTxDurationTest ();
+  TxDurationTest ();
+  virtual ~TxDurationTest ();
   virtual void DoRun (void);
 
 private:
@@ -65,20 +65,20 @@ private:
 };
 
 
-InterferenceHelperTxDurationTest::InterferenceHelperTxDurationTest ()
-  : TestCase ("InterferenceHelper TX Duration")
+TxDurationTest::TxDurationTest ()
+  : TestCase ("Wifi TX Duration")
 {
 }
 
 
-InterferenceHelperTxDurationTest::~InterferenceHelperTxDurationTest ()
+TxDurationTest::~TxDurationTest ()
 {
 }
 
 bool
-InterferenceHelperTxDurationTest::CheckPayloadDuration (uint32_t size, WifiMode payloadMode, uint32_t knownDurationMicroSeconds)
+TxDurationTest::CheckPayloadDuration (uint32_t size, WifiMode payloadMode, uint32_t knownDurationMicroSeconds)
 {
-  uint32_t calculatedDurationMicroSeconds = InterferenceHelper::GetPayloadDurationMicroSeconds (size, payloadMode);
+  uint32_t calculatedDurationMicroSeconds = WifiPhy::GetPayloadDurationMicroSeconds (size, payloadMode);
   if (calculatedDurationMicroSeconds != knownDurationMicroSeconds)
     {
       std::cerr << " size=" << size
@@ -92,9 +92,9 @@ InterferenceHelperTxDurationTest::CheckPayloadDuration (uint32_t size, WifiMode
 }
 
 bool
-InterferenceHelperTxDurationTest::CheckTxDuration (uint32_t size, WifiMode payloadMode, WifiPreamble preamble, uint32_t knownDurationMicroSeconds)
+TxDurationTest::CheckTxDuration (uint32_t size, WifiMode payloadMode, WifiPreamble preamble, uint32_t knownDurationMicroSeconds)
 {
-  uint32_t calculatedDurationMicroSeconds = InterferenceHelper::CalculateTxDuration (size, payloadMode, preamble).GetMicroSeconds ();
+  uint32_t calculatedDurationMicroSeconds = WifiPhy::CalculateTxDuration (size, payloadMode, preamble).GetMicroSeconds ();
   if (calculatedDurationMicroSeconds != knownDurationMicroSeconds)
     {
       std::cerr << " size=" << size
@@ -109,7 +109,7 @@ InterferenceHelperTxDurationTest::CheckTxDuration (uint32_t size, WifiMode paylo
 }
 
 void
-InterferenceHelperTxDurationTest::DoRun (void)
+TxDurationTest::DoRun (void)
 {
   bool retval = true;
 
@@ -188,7 +188,7 @@ public:
 TxDurationTestSuite::TxDurationTestSuite ()
   : TestSuite ("devices-wifi-tx-duration", UNIT)
 {
-  AddTestCase (new InterferenceHelperTxDurationTest);
+  AddTestCase (new TxDurationTest);
 }
 
 static TxDurationTestSuite g_txDurationTestSuite;
diff --git a/src/wifi/wscript b/src/wifi/wscript
index cfc7953fa..c1eb70423 100644
--- a/src/wifi/wscript
+++ b/src/wifi/wscript
@@ -71,7 +71,7 @@ def build(bld):
     obj_test.source = [
         'test/block-ack-test-suite.cc',
         'test/dcf-manager-test.cc',
-        'test/interference-helper-tx-duration-test.cc',
+        'test/tx-duration-test.cc',
         'test/wifi-test.cc',
         ]