diff --git a/lib/gsmtap.h b/lib/gsmtap.h
new file mode 100644
index 0000000..bf8226b
--- /dev/null
+++ b/lib/gsmtap.h
@@ -0,0 +1,72 @@
+#ifndef _GSMTAP_H
+#define _GSMTAP_H
+
+/* gsmtap header, pseudo-header in front of the actua GSM payload */
+
+/* GSMTAP is a generic header format for GSM protocol captures,
+ * it uses the IANA-assigned UDP port number 4729 and carries
+ * payload in various formats of GSM interfaces such as Um MAC
+ * blocks or Um bursts.
+ *
+ * Example programs generating GSMTAP data are airprobe
+ * (http://airprobe.org/) or OsmocomBB (http://bb.osmocom.org/)
+ */
+
+#include <stdint.h>
+
+#define GSMTAP_VERSION		0x02
+
+#define GSMTAP_TYPE_UM		0x01	/* A Layer 2 MAC block (23 bytes) */
+#define GSMTAP_TYPE_ABIS	0x02
+#define GSMTAP_TYPE_UM_BURST	0x03	/* raw burst bits */
+
+#define GSMTAP_BURST_UNKNOWN		0x00
+#define GSMTAP_BURST_FCCH		0x01
+#define GSMTAP_BURST_PARTIAL_SCH	0x02
+#define GSMTAP_BURST_SCH		0x03
+#define GSMTAP_BURST_CTS_SCH		0x04
+#define GSMTAP_BURST_COMPACT_SCH	0x05
+#define GSMTAP_BURST_NORMAL		0x06
+#define GSMTAP_BURST_DUMMY		0x07
+#define GSMTAP_BURST_ACCESS		0x08
+#define GSMTAP_BURST_NONE		0x09
+
+#define GSMTAP_CHANNEL_UNKNOWN	0x00
+#define GSMTAP_CHANNEL_BCCH	0x01
+#define GSMTAP_CHANNEL_CCCH	0x02
+#define GSMTAP_CHANNEL_RACH	0x03
+#define GSMTAP_CHANNEL_AGCH	0x04
+#define GSMTAP_CHANNEL_PCH	0x05
+#define GSMTAP_CHANNEL_SDCCH	0x06
+#define GSMTAP_CHANNEL_SDCCH4	0x07
+#define GSMTAP_CHANNEL_SDCCH8	0x08
+#define GSMTAP_CHANNEL_TCH_F	0x09
+#define GSMTAP_CHANNEL_TCH_H	0x0a
+#define GSMTAP_CHANNEL_ACCH	0x80
+
+#define GSMTAP_ARFCN_F_PCS	0x8000
+#define GSMTAP_ARFCN_F_UPLINK	0x4000
+#define GSMTAP_ARFCN_MASK	0x3fff
+
+#define GSMTAP_UDP_PORT		4729	/* officially registered with IANA */
+
+struct gsmtap_hdr {
+	uint8_t version;	/* version, set to GSMTAP_VERSION */
+	uint8_t hdr_len;	/* length in number of 32bit words */
+	uint8_t type;		/* see GSMTAP_TYPE_* */
+	uint8_t timeslot;	/* timeslot (0..7 on Um) */
+
+	uint16_t arfcn;		/* ARFCN (frequency) */
+	int8_t signal_dbm;	/* signal level in dBm */
+	int8_t snr_db;		/* signal/noise ratio in dB */
+
+	uint32_t frame_number;	/* GSM Frame Number (FN) */
+
+	uint8_t sub_type;	/* Type of burst/channel, see above */
+	uint8_t antenna_nr;	/* Antenna Number */
+	uint8_t sub_slot;	/* sub-slot within timeslot */
+	uint8_t res;		/* reserved for future use (RFU) */
+
+} __attribute__((packed));
+
+#endif /* _GSMTAP_H */
diff --git a/lib/qa_gsm.cc b/lib/qa_gsm.cc
new file mode 100644
index 0000000..b84c0ea
--- /dev/null
+++ b/lib/qa_gsm.cc
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2012 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio 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.
+ *
+ * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+/*
+ * This class gathers together all the test cases for the gr-filter
+ * directory into a single test suite.  As you create new test cases,
+ * add them here.
+ */
+
+#include "qa_gsm.h"
+#include "qa_receiver.h"
+
+//this is just a stub created by gr_modtool
+
+CppUnit::TestSuite *
+qa_gsm::suite()
+{
+  CppUnit::TestSuite *s = new CppUnit::TestSuite("gsm");
+  s->addTest(gr::gsm::qa_receiver::suite());
+
+  return s;
+}
diff --git a/lib/qa_gsm.h b/lib/qa_gsm.h
new file mode 100644
index 0000000..f5ce6cd
--- /dev/null
+++ b/lib/qa_gsm.h
@@ -0,0 +1,40 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2012 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio 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.
+ *
+ * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef _QA_GSM_H_
+#define _QA_GSM_H_
+
+#include <gnuradio/attributes.h>
+#include <cppunit/TestSuite.h>
+
+//this is just a stub created by gr_modtool
+
+//! collect all the tests for the gr-filter directory
+
+class __GR_ATTR_EXPORT qa_gsm
+{
+ public:
+  //! return suite of tests for all of gr-filter directory
+  static CppUnit::TestSuite *suite();
+};
+
+#endif /* _QA_GSM_H_ */
diff --git a/lib/qa_receiver.cc b/lib/qa_receiver.cc
new file mode 100644
index 0000000..34949dd
--- /dev/null
+++ b/lib/qa_receiver.cc
@@ -0,0 +1,40 @@
+/* -*- c++ -*- */
+/* 
+ * Copyright 2014 <+YOU OR YOUR COMPANY+>.
+ * 
+ * This 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.
+ * 
+ * This software 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 this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+#include <gnuradio/attributes.h>
+#include <cppunit/TestAssert.h>
+#include "qa_receiver.h"
+#include <gsm/receiver.h>
+
+//this is just a stub created by gr_modtool
+
+namespace gr {
+  namespace gsm {
+
+    void
+    qa_receiver::t1()
+    {
+        // Put test here
+    }
+
+  } /* namespace gsm */
+} /* namespace gr */
+
diff --git a/lib/qa_receiver.h b/lib/qa_receiver.h
new file mode 100644
index 0000000..085b45f
--- /dev/null
+++ b/lib/qa_receiver.h
@@ -0,0 +1,47 @@
+/* -*- c++ -*- */
+/* 
+ * Copyright 2014 <+YOU OR YOUR COMPANY+>.
+ * 
+ * This 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.
+ * 
+ * This software 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 this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+//this is just a stub created by gr_modtool
+
+#ifndef _QA_RECEIVER_H_
+#define _QA_RECEIVER_H_
+
+#include <cppunit/extensions/HelperMacros.h>
+#include <cppunit/TestCase.h>
+
+namespace gr {
+  namespace gsm {
+
+    class qa_receiver : public CppUnit::TestCase
+    {
+    public:
+      CPPUNIT_TEST_SUITE(qa_receiver);
+      CPPUNIT_TEST(t1);
+      CPPUNIT_TEST_SUITE_END();
+
+    private:
+      void t1();
+    };
+
+  } /* namespace gsm */
+} /* namespace gr */
+
+#endif /* _QA_RECEIVER_H_ */
+