diff --git a/src/devices/wifi/dca-txop.cc b/src/devices/wifi/dca-txop.cc
index c20bca9fe..0aff87242 100644
--- a/src/devices/wifi/dca-txop.cc
+++ b/src/devices/wifi/dca-txop.cc
@@ -232,7 +232,7 @@ DcaTxop::GetAifsn (void) const
 }
 
 void 
-DcaTxop::Queue (Ptr<const Packet> packet, WifiMacHeader const &hdr)
+DcaTxop::Queue (Ptr<const Packet> packet, const WifiMacHeader &hdr)
 {
   NS_LOG_FUNCTION (this << packet << &hdr);
   WifiMacTrailer fcs;
diff --git a/src/devices/wifi/dca-txop.h b/src/devices/wifi/dca-txop.h
index 55a4f2106..7c4e2bb91 100644
--- a/src/devices/wifi/dca-txop.h
+++ b/src/devices/wifi/dca-txop.h
@@ -67,8 +67,8 @@ class DcaTxop : public Object
 public:
   static TypeId GetTypeId (void);
 
-  typedef Callback <void, WifiMacHeader const&> TxOk;
-  typedef Callback <void, WifiMacHeader const&> TxFailed;
+  typedef Callback <void, const WifiMacHeader&> TxOk;
+  typedef Callback <void, const WifiMacHeader&> TxFailed;
 
   DcaTxop ();
   ~DcaTxop ();
@@ -104,7 +104,7 @@ public:
    * Store the packet in the internal queue until it
    * can be sent safely.
    */
-  void Queue (Ptr<const Packet> packet, WifiMacHeader const &hdr);
+  void Queue (Ptr<const Packet> packet, const WifiMacHeader &hdr);
 
 private:
   class TransmissionListener;