diff --git a/library/RTP_Emulation.ttcn b/library/RTP_Emulation.ttcn
index fcb158b..2494d74 100644
--- a/library/RTP_Emulation.ttcn
+++ b/library/RTP_Emulation.ttcn
@@ -119,7 +119,9 @@
 	/* number of packets received wrong payload type */
 	integer num_pkts_rx_err_pt,
 	/* number of packets received during Rx disable */
-	integer num_pkts_rx_err_disabled
+	integer num_pkts_rx_err_disabled,
+	/* number of packets received with mismatching payload */
+	integer num_pkts_rx_err_payload
 }
 
 const RtpemStats c_RtpemStatsReset := {
@@ -130,7 +132,8 @@
 	num_pkts_rx_err_seq := 0,
 	num_pkts_rx_err_ts := 0,
 	num_pkts_rx_err_pt := 0,
-	num_pkts_rx_err_disabled := 0
+	num_pkts_rx_err_disabled := 0,
+	num_pkts_rx_err_payload := 0
 }
 
 type record RtpemConfig {
@@ -139,6 +142,7 @@
 	integer tx_duration_ms,
 	BIT32_BO_LAST tx_ssrc,
 	octetstring tx_fixed_payload optional,
+	octetstring rx_fixed_payload optional,
 	boolean iuup_mode,
 	boolean iuup_tx_init
 };
@@ -149,6 +153,7 @@
 	tx_duration_ms := 20,
 	tx_ssrc := '11011110101011011011111011101111'B,
 	tx_fixed_payload := '01020304'O,
+	rx_fixed_payload := '01020304'O,
 	iuup_mode := false,
 	iuup_tx_init := true
 }
@@ -276,6 +281,10 @@
 		setverdict(fail, "RTP packets received while RX was disabled");
 		mtc.stop;
 	}
+	if (s.num_pkts_rx_err_payload != 0) {
+		setverdict(fail, "RTP packets with mismatching payload received");
+		mtc.stop;
+	}
 }
 
 template PDU_RTP ts_RTP(BIT32_BO_LAST ssrc, INT7b pt, LIN2_BO_LAST seq, uint32_t ts,
@@ -437,8 +446,6 @@
 
 		/* process received RTCP/RTP if receiver enabled */
 		[g_rx_enabled] RTP.receive(tr_rtp) -> value rx_rtp {
-			//log("RX RTP: ", rx_rtp);
-
 			/* increment counters */
 			if (rx_rtp.msg.rtp.payload_type != g_cfg.tx_payload_type) {
 				g_stats_rtp.num_pkts_rx_err_pt := g_stats_rtp.num_pkts_rx_err_pt+1;
@@ -446,6 +453,9 @@
 			g_stats_rtp.num_pkts_rx := g_stats_rtp.num_pkts_rx+1;
 			g_stats_rtp.bytes_payload_rx := g_stats_rtp.bytes_payload_rx +
 								lengthof(rx_rtp.msg.rtp.data);
+			if (ispresent(g_cfg.rx_fixed_payload) and rx_rtp.msg.rtp.data != g_cfg.rx_fixed_payload) {
+				g_stats_rtp.num_pkts_rx_err_payload := g_stats_rtp.num_pkts_rx_err_payload + 1;
+			}
 			if (g_cfg.iuup_mode) {
 				rx_rtp.msg.rtp.data := f_IuUP_Em_rx_decaps(g_iuup_ent, rx_rtp.msg.rtp.data);
 			}