diff --git a/library/GSM_RR_Types.ttcn b/library/GSM_RR_Types.ttcn
index 2ceb1f8..ef209e4 100644
--- a/library/GSM_RR_Types.ttcn
+++ b/library/GSM_RR_Types.ttcn
@@ -357,6 +357,26 @@
 		req_ref.t3 := fn mod 51;
 		return req_ref
 	}
+	function tr_compute_ReqRef(template uint8_t ra, template GsmFrameNumber fn)
+	return template RequestReference {
+		var template RequestReference req_ref;
+		if (istemplatekind(ra, "?")) {
+			req_ref.ra := ?;
+		} else {
+			req_ref.ra := int2bit(valueof(ra), 8);
+		}
+		if (istemplatekind(fn, "?")) {
+			req_ref.t1p := ?;
+			req_ref.t2 := ?;
+			req_ref.t3 := ?;
+		} else {
+			var GsmFrameNumber fn_v := valueof(fn);
+			req_ref.t1p := (fn_v / 1326) mod 32;
+			req_ref.t2 := fn_v mod 26;
+			req_ref.t3 := fn_v mod 51;
+		}
+		return req_ref;
+	}
 
 	/* 10.5.2.40 */
 	type integer TimingAdvance (0..219);
@@ -674,7 +694,7 @@
 		with { extension "prototype(convert) decode(RAW)" };
 
 
-	template GsmRrMessage ts_IMM_ASS(uint8_t ra, GsmFrameNumber fn, TimingAdvance ta,
+	template (value) GsmRrMessage ts_IMM_ASS(uint8_t ra, GsmFrameNumber fn, TimingAdvance ta,
 						ChannelDescription ch_desc, MobileAllocation ma) := {
 		header := t_RrHeader(IMMEDIATE_ASSIGNMENT, 0),
 		payload := {
@@ -696,6 +716,31 @@
 		}
 	};
 
+	template GsmRrMessage tr_IMM_ASS(template uint8_t ra := ?, template GsmFrameNumber fn := ?,
+					 template TimingAdvance ta := ?,
+					 template ChannelDescription ch_desc := ?,
+					 template MobileAllocation ma := ?) := {
+		header := t_RrHeader(IMMEDIATE_ASSIGNMENT, 0),
+		payload := {
+			imm_ass := {
+				ded_or_tbf := {
+					spare := '0'B,
+					tma := false,
+					downlink := false,
+					tbf := false
+				},
+				page_mode := PAGE_MODE_NORMAL,
+				chan_desc := ch_desc,
+				pkt_chan_desc := omit,
+				req_ref := tr_compute_ReqRef(ra, fn),
+				timing_advance := ta,
+				mobile_allocation := ma,
+				rest_octets := *
+			}
+		}
+	};
+
+
 	template (value) GsmRrL3Message ts_MEAS_REP(boolean valid, uint6_t rxl_f, uint6_t rxl_s,
 						  uint3_t rxq_f, uint3_t rxq_s,
 						  template (omit) NcellReports reps) := {