diff --git a/src/bts.cpp b/src/bts.cpp
index 61dfc87..0356718 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -307,7 +307,7 @@
 		if (tbf->state_is_not(GPRS_RLCMAC_RELEASING)
 		 && tbf->poll_state == GPRS_RLCMAC_POLL_SCHED
 		 && tbf->poll_fn == fn && tbf->trx->trx_no == trx
-		 && tbf->control_ts == ts) {
+		 && tbf->poll_ts == ts) {
 			return tbf;
 		}
 	}
@@ -325,7 +325,7 @@
 		if (tbf->state_is_not(GPRS_RLCMAC_RELEASING)
 		 && tbf->poll_state == GPRS_RLCMAC_POLL_SCHED
 		 && tbf->poll_fn == fn && tbf->trx->trx_no == trx
-		 && tbf->control_ts == ts) {
+		 && tbf->poll_ts == ts) {
 			return tbf;
 		}
 	}
diff --git a/src/tbf.cpp b/src/tbf.cpp
index 35a004c..6e51628 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -61,6 +61,7 @@
 	ul_ack_state(GPRS_RLCMAC_UL_ACK_NONE),
 	poll_state(GPRS_RLCMAC_POLL_NONE),
 	poll_fn(0),
+	poll_ts(0),
 	n3105(0),
 	T(0),
 	num_T_exp(0),
@@ -436,8 +437,8 @@
 
 void gprs_rlcmac_tbf::poll_timeout()
 {
-	LOGP(DRLCMAC, LOGL_NOTICE, "%s poll timeout for FN=%d (curr FN %d)\n",
-		tbf_name(this), poll_fn, bts->current_frame_number());
+	LOGP(DRLCMAC, LOGL_NOTICE, "%s poll timeout for FN=%d, TS=%d (curr FN %d)\n",
+		tbf_name(this), poll_fn, poll_ts, bts->current_frame_number());
 
 	poll_state = GPRS_RLCMAC_POLL_NONE;
 
@@ -935,10 +936,11 @@
 	if (poll_ass_dl) {
 		poll_state = GPRS_RLCMAC_POLL_SCHED;
 		poll_fn = (fn + 13) % 2715648;
+		poll_ts = ts;
 		dl_ass_state = GPRS_RLCMAC_DL_ASS_WAIT_ACK;
 		LOGP(DRLCMACDL, LOGL_INFO,
-			"%s Scheduled DL Assignment polling on FN=%d\n",
-			name(), poll_fn);
+			"%s Scheduled DL Assignment polling on FN=%d, TS=%d\n",
+			name(), poll_fn, poll_ts);
 	} else {
 		dl_ass_state = GPRS_RLCMAC_DL_ASS_NONE;
 		new_dl_tbf->set_state(GPRS_RLCMAC_FLOW);
@@ -1004,10 +1006,11 @@
 
 	poll_state = GPRS_RLCMAC_POLL_SCHED;
 	poll_fn = (fn + 13) % 2715648;
+	poll_ts = ts;
 	ul_ass_state = GPRS_RLCMAC_UL_ASS_WAIT_ACK;
 	LOGP(DRLCMACDL, LOGL_INFO,
-		"%s Scheduled UL Assignment polling on FN=%d\n",
-		name(), poll_fn);
+		"%s Scheduled UL Assignment polling on FN=%d, TS=%d\n",
+		name(), poll_fn, poll_ts);
 
 	return msg;
 }
diff --git a/src/tbf.h b/src/tbf.h
index f3487c6..d23cf93 100644
--- a/src/tbf.h
+++ b/src/tbf.h
@@ -177,6 +177,7 @@
 
 	enum gprs_rlcmac_tbf_poll_state poll_state;
 	uint32_t poll_fn; /* frame number to poll */
+	uint8_t poll_ts; /* TS to poll */
 
 	gprs_rlc m_rlc;
 	
diff --git a/src/tbf_dl.cpp b/src/tbf_dl.cpp
index 21a042e..10b376f 100644
--- a/src/tbf_dl.cpp
+++ b/src/tbf_dl.cpp
@@ -594,6 +594,7 @@
 			/* schedule polling */
 			poll_state = GPRS_RLCMAC_POLL_SCHED;
 			poll_fn = (fn + 13) % 2715648;
+			poll_ts = ts;
 
 			/* Clear poll timeout flag */
 			state_flags &= ~(1 << GPRS_RLCMAC_FLAG_TO_DL_ACK);
@@ -609,7 +610,7 @@
 
 			LOGP(DRLCMACDL, LOGL_INFO,
 				"%s Scheduled Ack/Nack polling on FN=%d, TS=%d\n",
-				name(), poll_fn, ts);
+				name(), poll_fn, poll_ts);
 		}
 	}
 
diff --git a/src/tbf_ul.cpp b/src/tbf_ul.cpp
index 1ccfa27..4754e11 100644
--- a/src/tbf_ul.cpp
+++ b/src/tbf_ul.cpp
@@ -127,6 +127,7 @@
 	if (final) {
 		poll_state = GPRS_RLCMAC_POLL_SCHED;
 		poll_fn = (fn + 13) % 2715648;
+		poll_ts = ts;
 		/* waiting for final acknowledge */
 		ul_ack_state = GPRS_RLCMAC_UL_ACK_WAIT_ACK;
 		m_final_ack_sent = 1;
diff --git a/tests/tbf/TbfTest.cpp b/tests/tbf/TbfTest.cpp
index d2b4cfc..0ff4f98 100644
--- a/tests/tbf/TbfTest.cpp
+++ b/tests/tbf/TbfTest.cpp
@@ -605,6 +605,7 @@
 	RlcMacUplink_t ulreq = {0};
 
 	OSMO_ASSERT(tbf->poll_fn != 0);
+	OSMO_ASSERT(tbf->is_control_ts(tbf->poll_ts));
 
 	ulreq.u.MESSAGE_TYPE = MT_PACKET_CONTROL_ACK;
 	Packet_Control_Acknowledgement_t *ctrl_ack =
@@ -612,7 +613,7 @@
 
 	ctrl_ack->PayloadType = GPRS_RLCMAC_CONTROL_BLOCK;
 	ctrl_ack->TLLI = tbf->tlli();
-	send_ul_mac_block(tbf->bts, tbf->trx->trx_no, tbf->control_ts,
+	send_ul_mac_block(tbf->bts, tbf->trx->trx_no, tbf->poll_ts,
 		&ulreq, tbf->poll_fn);
 }
 
@@ -1043,7 +1044,7 @@
 	ack->DOWNLINK_TFI = dl_tbf1->tfi();
 	ack->Ack_Nack_Description.FINAL_ACK_INDICATION = 1;
 
-	send_ul_mac_block(&the_bts, 0, ts_no, &ulreq, dl_tbf1->poll_fn);
+	send_ul_mac_block(&the_bts, 0, dl_tbf1->poll_ts, &ulreq, dl_tbf1->poll_fn);
 
 	OSMO_ASSERT(dl_tbf1->state_is(GPRS_RLCMAC_WAIT_RELEASE));
 
diff --git a/tests/tbf/TbfTest.err b/tests/tbf/TbfTest.err
index 350966e..80f3f85 100644
--- a/tests/tbf/TbfTest.err
+++ b/tests/tbf/TbfTest.err
@@ -61,7 +61,7 @@
 TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW)  start Packet Downlink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Downlink Assignment -------------------------
-TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW) Scheduled DL Assignment polling on FN=13
+TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW) Scheduled DL Assignment polling on FN=13, TS=4
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW) (TRX=0, TS=4)
 Sending data request: trx=0 ts=4 sapi=5 arfcn=0 fn=0 block=0 data=4f 08 20 00 44 02 00 02 08 04 00 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Scheduling data message at RTS for DL TFI=0 (TRX=0, TS=4) prio=3
@@ -142,7 +142,7 @@
 TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW)  start Packet Downlink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Downlink Assignment -------------------------
-TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW) Scheduled DL Assignment polling on FN=13
+TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW) Scheduled DL Assignment polling on FN=13, TS=4
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW) (TRX=0, TS=4)
 Sending data request: trx=0 ts=4 sapi=5 arfcn=0 fn=0 block=0 data=4f 08 20 00 44 02 00 02 08 04 00 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Scheduling data message at RTS for DL TFI=0 (TRX=0, TS=4) prio=3
@@ -223,7 +223,7 @@
 TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW)  start Packet Downlink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Downlink Assignment -------------------------
-TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW) Scheduled DL Assignment polling on FN=13
+TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW) Scheduled DL Assignment polling on FN=13, TS=4
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW) (TRX=0, TS=4)
 Sending data request: trx=0 ts=4 sapi=5 arfcn=0 fn=0 block=0 data=4f 08 20 00 44 02 00 02 08 04 00 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Scheduling data message at RTS for DL TFI=0 (TRX=0, TS=4) prio=3
@@ -1549,7 +1549,7 @@
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN)s start Packet Uplink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Uplink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Uplink Assignment -------------------------
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283, TS=7
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654270 block=8 data=4f 28 5e 24 46 68 8f 1d 00 00 88 00 08 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))
@@ -1633,7 +1633,7 @@
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN)s start Packet Uplink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Uplink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Uplink Assignment -------------------------
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283, TS=7
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654270 block=8 data=4f 28 5e 24 46 68 8f 1d 00 00 88 00 08 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))
@@ -1683,7 +1683,7 @@
 TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=ASSIGN)  start Packet Downlink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Downlink Assignment -------------------------
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) Scheduled DL Assignment polling on FN=2654288
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) Scheduled DL Assignment polling on FN=2654288, TS=7
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654275 block=9 data=48 08 00 00 0c 72 00 02 08 00 80 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))
@@ -1731,7 +1731,7 @@
 Sending data request: trx=0 ts=0 sapi=2 arfcn=0 fn=0 block=0 data=2d 06 3f 10 0f 00 00 73 8c f6 07 00 c0 0c 68 ab 2b 2b 2b 2b 2b 2b 2b 
 Searching for first unallocated TFI: TRX=0
  Found TFI=1.
-TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=FINISHED) poll timeout for FN=2654292 (curr FN 2654335)
+TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=FINISHED) poll timeout for FN=2654292, TS=7 (curr FN 2654335)
 - Timeout for polling PACKET DOWNLINK ACK.
 - Assignment was on PACCH
 - No downlink ACK received yet
@@ -1765,7 +1765,7 @@
 TBF(TFI=1 TLLI=0xf5667788 DIR=UL STATE=ASSIGN)s start Packet Uplink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Uplink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Uplink Assignment -------------------------
-TBF(TFI=1 TLLI=0xf5667788 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654348
+TBF(TFI=1 TLLI=0xf5667788 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654348, TS=7
 Scheduling control message at RTS for TBF(TFI=1 TLLI=0xf5667788 DIR=UL STATE=ASSIGN) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654335 block=11 data=48 28 5e ac ce f1 0f 1d 00 00 88 40 09 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))
@@ -1835,7 +1835,7 @@
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN)s start Packet Uplink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Uplink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Uplink Assignment -------------------------
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283, TS=7
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654270 block=8 data=4f 28 5e 24 46 68 83 1d 00 00 88 00 08 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))
@@ -1930,7 +1930,7 @@
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN)s start Packet Uplink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Uplink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Uplink Assignment -------------------------
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654340
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654340, TS=7
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654327 block=9 data=4f 28 5e 24 46 68 83 1d 00 00 88 00 08 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))
@@ -2010,7 +2010,7 @@
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN)s start Packet Uplink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Uplink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Uplink Assignment -------------------------
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283, TS=7
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654270 block=8 data=4f 28 5e 24 46 68 83 1d 00 00 88 00 08 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))
@@ -2163,7 +2163,7 @@
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN)s start Packet Uplink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Uplink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Uplink Assignment -------------------------
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) Scheduled UL Assignment polling on FN=2654283, TS=7
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=ASSIGN) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654270 block=8 data=4f 28 5e 24 46 68 83 1d 00 00 88 00 08 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))
@@ -2252,7 +2252,7 @@
 TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=ASSIGN)  start Packet Downlink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Downlink Assignment -------------------------
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) Scheduled DL Assignment polling on FN=2654288
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) Scheduled DL Assignment polling on FN=2654288, TS=7
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654275 block=9 data=48 08 00 00 0c 72 00 02 08 00 80 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))
@@ -2881,7 +2881,7 @@
 TBF(TFI=1 TLLI=0xf1223344 DIR=DL STATE=ASSIGN)  start Packet Downlink Assignment (PACCH)
 +++++++++++++++++++++++++ TX : Packet Downlink Assignment +++++++++++++++++++++++++
 ------------------------- TX : Packet Downlink Assignment -------------------------
-TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=WAIT RELEASE) Scheduled DL Assignment polling on FN=2654413
+TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=WAIT RELEASE) Scheduled DL Assignment polling on FN=2654413, TS=7
 Scheduling control message at RTS for TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=WAIT RELEASE) (TRX=0, TS=7)
 Sending data request: trx=0 ts=7 sapi=5 arfcn=0 fn=2654400 block=2 data=48 08 20 08 0c 72 00 02 18 00 80 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 
 Got RLC block, coding scheme: CS-1, length: 23 (23))