diff --git a/include/osmocom/gsm/Makefile.am b/include/osmocom/gsm/Makefile.am
index c3670ec..547933e 100644
--- a/include/osmocom/gsm/Makefile.am
+++ b/include/osmocom/gsm/Makefile.am
@@ -1,5 +1,6 @@
 osmogsm_HEADERS = a5.h comp128.h gsm0808.h gsm48_ie.h mncc.h rxlev_stat.h \
-		  gsm0480.h gsm48.h gsm_utils.h rsl.h tlv.h abis_nm.h
+		  gsm0480.h gsm48.h gsm_utils.h rsl.h tlv.h abis_nm.h \
+		  sysinfo.h
 
 SUBDIRS = protocol
 
diff --git a/include/osmocom/gsm/protocol/gsm_04_08.h b/include/osmocom/gsm/protocol/gsm_04_08.h
index 3ad7dfd..39470e7 100644
--- a/include/osmocom/gsm/protocol/gsm_04_08.h
+++ b/include/osmocom/gsm/protocol/gsm_04_08.h
@@ -1257,6 +1257,9 @@
 	uint8_t rac;		/* Routing Area Code */
 } __attribute__ ((packed));
 
+#define GSM48_CELL_CHAN_DESC_SIZE	16
 
+#define GSM_MACBLOCK_LEN	23
+#define GSM_MACBLOCK_PADDING	0x2b
 
 #endif /* PROTO_GSM_04_08_H */
diff --git a/include/osmocom/gsm/sysinfo.h b/include/osmocom/gsm/sysinfo.h
new file mode 100644
index 0000000..a66f3f1
--- /dev/null
+++ b/include/osmocom/gsm/sysinfo.h
@@ -0,0 +1,40 @@
+#ifndef _OSMO_GSM_SYSINFO_H
+#define _OSMO_GSM_SYSINFO_H
+
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+
+enum osmo_sysinfo_type {
+	SYSINFO_TYPE_NONE,
+	SYSINFO_TYPE_1,
+	SYSINFO_TYPE_2,
+	SYSINFO_TYPE_3,
+	SYSINFO_TYPE_4,
+	SYSINFO_TYPE_5,
+	SYSINFO_TYPE_6,
+	SYSINFO_TYPE_7,
+	SYSINFO_TYPE_8,
+	SYSINFO_TYPE_9,
+	SYSINFO_TYPE_10,
+	SYSINFO_TYPE_13,
+	SYSINFO_TYPE_16,
+	SYSINFO_TYPE_17,
+	SYSINFO_TYPE_18,
+	SYSINFO_TYPE_19,
+	SYSINFO_TYPE_20,
+	SYSINFO_TYPE_2bis,
+	SYSINFO_TYPE_2ter,
+	SYSINFO_TYPE_2quater,
+	SYSINFO_TYPE_5bis,
+	SYSINFO_TYPE_5ter,
+	/* FIXME all the various bis and ter */
+	_MAX_SYSINFO_TYPE
+};
+
+typedef uint8_t sysinfo_buf_t[GSM_MACBLOCK_LEN];
+
+extern const struct value_string osmo_sitype_strs[_MAX_SYSINFO_TYPE];
+
+uint8_t gsm_sitype2rsl(enum osmo_sysinfo_type si_type);
+enum osmo_sysinfo_type osmo_rsl2sitype(uint8_t rsl_si);
+
+#endif /* _OSMO_GSM_SYSINFO_H */