diff --git a/lib/transmitter/gen_test_ab_impl.cc b/lib/transmitter/gen_test_ab_impl.cc
index bb9c9f6..1ce3658 100644
--- a/lib/transmitter/gen_test_ab_impl.cc
+++ b/lib/transmitter/gen_test_ab_impl.cc
@@ -25,6 +25,7 @@
 #endif
 
 #include <gnuradio/io_signature.h>
+#include <grgsm/endian.h>
 #include <grgsm/gsmtap.h>
 #include <grgsm/gsm_constants.h>
 #include "gen_test_ab_impl.h"
diff --git a/lib/transmitter/txtime_setter_impl.cc b/lib/transmitter/txtime_setter_impl.cc
index 9f3a24d..5934ef3 100644
--- a/lib/transmitter/txtime_setter_impl.cc
+++ b/lib/transmitter/txtime_setter_impl.cc
@@ -26,6 +26,7 @@
 #endif
 
 #include <gnuradio/io_signature.h>
+#include <grgsm/endian.h>
 #include <grgsm/gsmtap.h>
 
 #include "txtime_setter_impl.h"