diff --git a/lib/flow_control/uplink_downlink_splitter_impl.h b/lib/flow_control/uplink_downlink_splitter_impl.h
new file mode 100644
index 0000000..bc4368a
--- /dev/null
+++ b/lib/flow_control/uplink_downlink_splitter_impl.h
@@ -0,0 +1,43 @@
+/* -*- c++ -*- */
+/* @file
+ * @author Piotr Krysik <ptrkrysik@gmail.com>
+ * @section LICENSE
+ * 
+ * Gr-gsm is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * Gr-gsm is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with gr-gsm; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ * 
+ */
+
+#ifndef INCLUDED_GRGSM_UPLINK_DOWNLINK_SPLITTER_IMPL_H
+#define INCLUDED_GRGSM_UPLINK_DOWNLINK_SPLITTER_IMPL_H
+
+#include <grgsm/flow_control/uplink_downlink_splitter.h>
+
+namespace gr {
+  namespace grgsm {
+
+    class uplink_downlink_splitter_impl : public uplink_downlink_splitter
+    {
+     public:
+      uplink_downlink_splitter_impl();
+      ~uplink_downlink_splitter_impl();
+
+      void process_msg(pmt::pmt_t msg);
+    };
+  } // namespace grgsm
+} // namespace gr
+
+#endif /* INCLUDED_GRGSM_UPLINK_DOWNLINK_SPLITTER_IMPL_H */
+