diff --git a/src/wifi/model/channel-access-manager.cc b/src/wifi/model/channel-access-manager.cc
index 3336cbc89..bb2798e33 100644
--- a/src/wifi/model/channel-access-manager.cc
+++ b/src/wifi/model/channel-access-manager.cc
@@ -632,7 +632,7 @@ ChannelAccessManager::GetAccessGrantStart(bool ignoreNav) const
 }
 
 Time
-ChannelAccessManager::GetBackoffStartFor(Ptr<Txop> txop)
+ChannelAccessManager::GetBackoffStartFor(Ptr<Txop> txop) const
 {
     return GetBackoffStartFor(txop, GetAccessGrantStart());
 }
@@ -651,7 +651,7 @@ ChannelAccessManager::GetBackoffStartFor(Ptr<Txop> txop, Time accessGrantStart)
 }
 
 Time
-ChannelAccessManager::GetBackoffEndFor(Ptr<Txop> txop)
+ChannelAccessManager::GetBackoffEndFor(Ptr<Txop> txop) const
 {
     return GetBackoffEndFor(txop, GetAccessGrantStart());
 }
diff --git a/src/wifi/model/channel-access-manager.h b/src/wifi/model/channel-access-manager.h
index 0eb63861a..3299e3de1 100644
--- a/src/wifi/model/channel-access-manager.h
+++ b/src/wifi/model/channel-access-manager.h
@@ -157,6 +157,26 @@ class ChannelAccessManager : public Object
      */
     Time GetAccessGrantStart(bool ignoreNav = false) const;
 
+    /**
+     * Return the time when the backoff procedure
+     * started for the given Txop.
+     *
+     * \param txop the Txop
+     *
+     * \return the time when the backoff procedure started
+     */
+    Time GetBackoffStartFor(Ptr<Txop> txop) const;
+
+    /**
+     * Return the time when the backoff procedure
+     * ended (or will end) for the given Txop.
+     *
+     * \param txop the Txop
+     *
+     * \return the time when the backoff procedure ended (or will end)
+     */
+    Time GetBackoffEndFor(Ptr<Txop> txop) const;
+
     /**
      * \param qosTxop a QosTxop that needs to be disabled
      * \param duration the amount of time during which the QosTxop is disabled
@@ -393,24 +413,6 @@ class ChannelAccessManager : public Object
      */
     Time GetBackoffEndFor(Ptr<Txop> txop, Time accessGrantStart) const;
 
-    /**
-     * Return the time when the backoff procedure
-     * started for the given Txop.
-     *
-     * \param txop the Txop
-     *
-     * \return the time when the backoff procedure started
-     */
-    Time GetBackoffStartFor(Ptr<Txop> txop);
-    /**
-     * Return the time when the backoff procedure
-     * ended (or will end) for the given Txop.
-     *
-     * \param txop the Txop
-     *
-     * \return the time when the backoff procedure ended (or will end)
-     */
-    Time GetBackoffEndFor(Ptr<Txop> txop);
     /**
      * This method determines whether the medium has been idle during a period (of
      * non-null duration) immediately preceding the time this method is called. If