diff --git a/include/grgsm/CMakeLists.txt b/include/grgsm/CMakeLists.txt
index 0b58018..2f76929 100644
--- a/include/grgsm/CMakeLists.txt
+++ b/include/grgsm/CMakeLists.txt
@@ -25,6 +25,7 @@
     api.h
     gsmtap.h
     constants.h
+    gsm_constants.h
     DESTINATION include/grgsm
 )
 
diff --git a/lib/receiver/gsm_constants.h b/include/grgsm/gsm_constants.h
similarity index 99%
rename from lib/receiver/gsm_constants.h
rename to include/grgsm/gsm_constants.h
index 9052290..fd1d9e7 100644
--- a/lib/receiver/gsm_constants.h
+++ b/include/grgsm/gsm_constants.h
@@ -38,6 +38,7 @@
 #define USEFUL_BITS       142  //(2*(DATA_BITS+STEALING_BIT) + N_TRAIN_BITS )
 #define FCCH_BITS         USEFUL_BITS
 #define BURST_SIZE        (USEFUL_BITS+2*TAIL_BITS)
+#define ACCESS_BURST_SIZE 87
 #define PROCESSED_CHUNK   BURST_SIZE+2*GUARD_PERIOD
 
 #define SCH_DATA_LEN      39
diff --git a/lib/decoding/sch.c b/lib/decoding/sch.c
index 6d2e3eb..7af136c 100644
--- a/lib/decoding/sch.c
+++ b/lib/decoding/sch.c
@@ -21,7 +21,7 @@
  */
 
 #include <string.h>
-#include "gsm_constants.h"
+#include <grgsm/gsm_constants.h>
 
 #include "osmocom/coding/gsm0503_coding.h"
 #include <osmocom/core/utils.h>
diff --git a/lib/receiver/clock_offset_control_impl.cc b/lib/receiver/clock_offset_control_impl.cc
index 868cbc2..d62c801 100644
--- a/lib/receiver/clock_offset_control_impl.cc
+++ b/lib/receiver/clock_offset_control_impl.cc
@@ -25,7 +25,7 @@
 #endif
 
 #include <sch.h>
-#include <gsm_constants.h>
+#include <grgsm/gsm_constants.h>
 #include "clock_offset_control_impl.h"
 
 namespace gr
diff --git a/lib/receiver/receiver_config.h b/lib/receiver/receiver_config.h
index f68e3f6..0fcd68d 100644
--- a/lib/receiver/receiver_config.h
+++ b/lib/receiver/receiver_config.h
@@ -26,7 +26,7 @@
 #include <algorithm>
 #include <math.h>
 #include <stdint.h>
-#include <gsm_constants.h>
+#include <grgsm/gsm_constants.h>
 
 class multiframe_configuration
 {
diff --git a/lib/receiver/receiver_impl.h b/lib/receiver/receiver_impl.h
index d43bb27..c216d90 100644
--- a/lib/receiver/receiver_impl.h
+++ b/lib/receiver/receiver_impl.h
@@ -25,7 +25,7 @@
 
 #include <grgsm/receiver/receiver.h>
 #include <grgsm/gsmtap.h>
-#include <gsm_constants.h>
+#include <grgsm/gsm_constants.h>
 #include <receiver_config.h>
 #include <vector>
 #include "time_sample_ref.h"
diff --git a/lib/receiver/viterbi_detector.cc b/lib/receiver/viterbi_detector.cc
index 4e8fb3a..3dce379 100644
--- a/lib/receiver/viterbi_detector.cc
+++ b/lib/receiver/viterbi_detector.cc
@@ -56,7 +56,7 @@
  */
 
 #include <gnuradio/gr_complex.h>
-#include <gsm_constants.h>
+#include <grgsm/gsm_constants.h>
 #include <cmath>
 
 #define PATHS_NUM (1 << (CHAN_IMP_RESP_LENGTH-1))