diff --git a/sysinfo/GSM_Types.ttcn b/sysinfo/GSM_Types.ttcn
index 70051bd..9098e1e 100644
--- a/sysinfo/GSM_Types.ttcn
+++ b/sysinfo/GSM_Types.ttcn
@@ -8,6 +8,10 @@
 	import from General_Types all;
 	import from Osmocom_Types all;
 
+	type integer GsmArfcn (0..1023);
+	type integer UmtsArfcn (0..16383);
+	type integer UmtsScramblingCode (0..511);
+
 	/* Table 10.4.1 of Section 10.4 / 3GPP TS 44.018 */
 	type enumerated RrMessageType {
 		ADDITIONAL_ASSIGNMENT		('00111011'B),