lr-wpan: Remove {Get,Set}UnitBackoffPeriod() functions

Move the corresponding constant to lr-wpan-constants.h

CHANGES.md

@@ -30,6 +30,7 @@ Changes from ns-3.37 to ns-3.38
 * (internet) `TcpCubic` attribute `HyStartDetect` changed from `int` to `enum HybridSSDetectionMode`.
 * (internet-apps) Classes `v4Ping` and `Ping6` will be deprecated and removed in the future, replaced by the new `Ping` class.
 * (lr-wpan) Add file `src/lr-wpan/model/lr-wpan-constants.h` with common constants of the LR-WPAN module.
+* (lr-wpan) Remove the functions `LrWpanCsmaCa::GetUnitBackoffPeriod()` and `LrWpanCsmaCa::SetUnitBackoffPeriod()`, and move the constant `m_aUnitBackoffPeriod` to `src/lr-wpan/model/lr-wpan-constants.h`.
 
 ### Changes to build system
 

src/lr-wpan/model/lr-wpan-constants.h

@@ -96,6 +96,11 @@ constexpr uint32_t aMaxPhyPacketSize{127};
  */
 constexpr uint32_t aTurnaroundTime{12};
 
+/**
+ * Number of symbols per CSMA/CA time unit, default 20 symbols.
+ */
+constexpr uint32_t aUnitBackoffPeriod{20};
+
 /** @} */
 
 } // namespace lrwpan

src/lr-wpan/model/lr-wpan-csmaca.cc

@@ -61,7 +61,6 @@ LrWpanCsmaCa::LrWpanCsmaCa()
     m_macMinBE = 3;
     m_macMaxBE = 5;
     m_macMaxCSMABackoffs = 4;
-    m_aUnitBackoffPeriod = 20; // symbols
     m_random = CreateObject<UniformRandomVariable>();
     m_BE = m_macMinBE;
     m_ccaRequestRunning = false;
@@ -171,20 +170,6 @@ LrWpanCsmaCa::GetMacMaxCSMABackoffs() const
     return m_macMaxCSMABackoffs;
 }
 
-void
-LrWpanCsmaCa::SetUnitBackoffPeriod(uint64_t unitBackoffPeriod)
-{
-    NS_LOG_FUNCTION(this << unitBackoffPeriod);
-    m_aUnitBackoffPeriod = unitBackoffPeriod;
-}
-
-uint64_t
-LrWpanCsmaCa::GetUnitBackoffPeriod() const
-{
-    NS_LOG_FUNCTION(this);
-    return m_aUnitBackoffPeriod;
-}
-
 Time
 LrWpanCsmaCa::GetTimeToNextSlot() const
 {
@@ -221,8 +206,8 @@ LrWpanCsmaCa::GetTimeToNextSlot() const
 
     // get a close value to the the boundary in symbols
     elapsedSuperframeSymbols = elapsedSuperframe.GetSeconds() * symbolRate;
-    symbolsToBoundary =
-        m_aUnitBackoffPeriod - std::fmod((double)elapsedSuperframeSymbols, m_aUnitBackoffPeriod);
+    symbolsToBoundary = lrwpan::aUnitBackoffPeriod -
+                        std::fmod((double)elapsedSuperframeSymbols, lrwpan::aUnitBackoffPeriod);
 
     timeAtBoundary = Seconds((double)(elapsedSuperframeSymbols + symbolsToBoundary) / symbolRate);
 
@@ -310,7 +295,7 @@ LrWpanCsmaCa::RandomBackoffDelay()
     }
 
     randomBackoff =
-        Seconds((double)(m_randomBackoffPeriodsLeft * GetUnitBackoffPeriod()) / symbolRate);
+        Seconds((double)(m_randomBackoffPeriodsLeft * lrwpan::aUnitBackoffPeriod) / symbolRate);
 
     if (IsUnSlottedCsmaCa())
     {
@@ -332,14 +317,14 @@ LrWpanCsmaCa::RandomBackoffDelay()
                      << randomBackoff.As(Time::S) << ")");
 
         NS_LOG_DEBUG("Backoff periods left in CAP: "
-                     << ((timeLeftInCap.GetSeconds() * symbolRate) / m_aUnitBackoffPeriod) << " ("
-                     << (timeLeftInCap.GetSeconds() * symbolRate) << " symbols or "
+                     << ((timeLeftInCap.GetSeconds() * symbolRate) / lrwpan::aUnitBackoffPeriod)
+                     << " (" << (timeLeftInCap.GetSeconds() * symbolRate) << " symbols or "
                      << timeLeftInCap.As(Time::S) << ")");
 
         if (randomBackoff >= timeLeftInCap)
         {
             uint64_t usedBackoffs =
-                (double)(timeLeftInCap.GetSeconds() * symbolRate) / m_aUnitBackoffPeriod;
+                (double)(timeLeftInCap.GetSeconds() * symbolRate) / lrwpan::aUnitBackoffPeriod;
             m_randomBackoffPeriodsLeft -= usedBackoffs;
             NS_LOG_DEBUG("No time in CAP to complete backoff delay, deferring to the next CAP");
             m_endCapEvent =

src/lr-wpan/model/lr-wpan-csmaca.h

@@ -149,22 +149,6 @@ class LrWpanCsmaCa : public Object
      * \return the maximum number of backoffs
      */
     uint8_t GetMacMaxCSMABackoffs() const;
-    /**
-     * Set the number of symbols forming the basic time period used by the
-     * CSMA-CA algorithm.
-     * See IEEE 802.15.4-2006, section 7.4.1, Table 85.
-     *
-     * \param unitBackoffPeriod the period length in symbols
-     */
-    void SetUnitBackoffPeriod(uint64_t unitBackoffPeriod);
-    /**
-     * Get the number of symbols forming the basic time period used by the
-     * CSMA-CA algorithm.
-     * See IEEE 802.15.4-2006, section 7.4.1, Table 85.
-     *
-     * \return the period length in symbols
-     */
-    uint64_t GetUnitBackoffPeriod() const;
     /**
      * Locates the time to the next backoff period boundary in the SUPERFRAME
      * and returns the amount of time left to this moment.
@@ -277,7 +261,7 @@ class LrWpanCsmaCa : public Object
      */
     bool m_isSlotted;
     /**
-     * The MAC instance for which this CSMA/CA implemenation is configured.
+     * The MAC instance for which this CSMA/CA implementation is configured.
      */
     Ptr<LrWpanMac> m_mac;
     /**
@@ -299,7 +283,7 @@ class LrWpanCsmaCa : public Object
     /**
      * Minimum backoff exponent. 0 - macMaxBE, default 3
      */
-    uint8_t m_macMinBE; //
+    uint8_t m_macMinBE;
     /**
      * Maximum backoff exponent. 3 - 8, default 5
      */
@@ -308,10 +292,6 @@ class LrWpanCsmaCa : public Object
      * Maximum number of backoffs. 0 - 5, default 4
      */
     uint8_t m_macMaxCSMABackoffs;
-    /**
-     * Number of symbols per CSMA/CA time unit, default 20 symbols.
-     */
-    uint64_t m_aUnitBackoffPeriod;
     /**
      * Count the number of remaining random backoff periods left to delay.
      */

src/lr-wpan/model/lr-wpan-mac.cc

@@ -3435,7 +3435,7 @@ LrWpanMac::ChangeMacState(LrWpanMacState newState)
 uint64_t
 LrWpanMac::GetMacAckWaitDuration() const
 {
-    return m_csmaCa->GetUnitBackoffPeriod() + lrwpan::aTurnaroundTime + m_phy->GetPhySHRDuration() +
+    return lrwpan::aUnitBackoffPeriod + lrwpan::aTurnaroundTime + m_phy->GetPhySHRDuration() +
            ceil(6 * m_phy->GetPhySymbolsPerOctet());
 }