diff --git a/gprs_gb/NS_Types.ttcn b/gprs_gb/NS_Types.ttcn
index ee2444d..bd04a66 100644
--- a/gprs_gb/NS_Types.ttcn
+++ b/gprs_gb/NS_Types.ttcn
@@ -57,6 +57,15 @@
 		NS_CAUSE_IP_TEST_FAILEDA			('00010100'B)
 	} with { variant "FIELDLENGTH(8)" };
 
+	/* TS 48.016 10.3.9 */
+	type record NsSduControlBits {
+		BIT6	spare,
+		boolean c,
+		boolean r
+	} with { variant (c) "FIELDLENGTH(1)"
+		 variant (r) "FIELDLENGTH(1)"
+	};
+
 	type uint16_t Nsvci;
 	type uint16_t Nsei;
 
@@ -90,11 +99,29 @@
 
 	type record of NsTLV NsTLVs;
 
-	type record NsPdu {
-		NsPduType	pdu_type,
+	type record NsPduUnitdata {
+		NsSduControlBits	control_bits,
+		BssgpBvci		bvci,
+		octetstring		sdu
+	} with { variant "" };
+
+	type record NsPduOther {
 		NsTLVs		tlvs optional
 	} with { variant "" };
 
+	type union NsPduUnion {
+		NsPduUnitdata	unitdata,
+		NsPduOther	other
+	} with { variant "" };
+
+	type record NsPdu {
+		NsPduType	pdu_type,
+		NsPduUnion	u
+	} with { variant (u) "CROSSTAG(
+				unitdata,		pdu_type = NS_PDUT_NS_UNITDATA;
+				other,			OTHERWISE)"
+	};
+
 	external function enc_NsPdu(in NsPdu pdu) return octetstring
 		with { extension "prototype(convert) encode(RAW)" };
 	external function dec_NsPdu(in octetstring stream) return NsPdu