diff --git a/src/gprs_rlcmac_sched.c b/src/gprs_rlcmac_sched.c
new file mode 100644
index 0000000..edc2937
--- /dev/null
+++ b/src/gprs_rlcmac_sched.c
@@ -0,0 +1,265 @@
+/* PDCH scheduler
+ *
+ * Copyright (C) 2012 Andreas Eversberg <jolly@eversberg.eu>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+ 
+#include <gprs_bssgp_pcu.h>
+#include <gprs_rlcmac.h>
+#include <gprs_rlcmac_ctrl.h>
+#include <pcu_l1_if.h>
+
+uint32_t sched_poll(uint8_t trx, uint8_t ts, uint32_t fn, uint8_t block_nr,
+		    struct gprs_rlcmac_tbf **poll_tbf,
+		    struct gprs_rlcmac_tbf **ul_ass_tbf,
+		    struct gprs_rlcmac_tbf **dl_ass_tbf,
+		    struct gprs_rlcmac_tbf **ul_ack_tbf)
+{
+	struct gprs_rlcmac_tbf *tbf;
+	uint32_t poll_fn;
+
+	/* check special TBF for events */
+	poll_fn = fn + 4;
+	if ((block_nr % 3) == 2)
+		poll_fn ++;
+	poll_fn = poll_fn % 2715648;
+	llist_for_each_entry(tbf, &gprs_rlcmac_ul_tbfs, list) {
+		/* this trx, this ts */
+		if (tbf->trx != trx || tbf->control_ts != ts)
+			continue;
+		/* polling for next uplink block */
+		if (tbf->poll_state == GPRS_RLCMAC_POLL_SCHED
+		 && tbf->poll_fn == poll_fn)
+			*poll_tbf = tbf;
+		if (tbf->ul_ack_state == GPRS_RLCMAC_UL_ACK_SEND_ACK)
+			*ul_ack_tbf = tbf;
+		if (tbf->dl_ass_state == GPRS_RLCMAC_DL_ASS_SEND_ASS)
+			*dl_ass_tbf = tbf;
+		if (tbf->ul_ass_state == GPRS_RLCMAC_UL_ASS_SEND_ASS)
+			*ul_ass_tbf = tbf;
+	}
+	llist_for_each_entry(tbf, &gprs_rlcmac_dl_tbfs, list) {
+		/* this trx, this ts */
+		if (tbf->trx != trx || tbf->control_ts != ts)
+			continue;
+		/* polling for next uplink block */
+		if (tbf->poll_state == GPRS_RLCMAC_POLL_SCHED
+		 && tbf->poll_fn == poll_fn)
+			*poll_tbf = tbf;
+		if (tbf->dl_ass_state == GPRS_RLCMAC_DL_ASS_SEND_ASS)
+			*dl_ass_tbf = tbf;
+		if (tbf->ul_ass_state == GPRS_RLCMAC_UL_ASS_SEND_ASS)
+			*ul_ass_tbf = tbf;
+	}
+
+	return poll_fn;
+}
+
+uint8_t sched_select_uplink(uint8_t trx, uint8_t ts, uint32_t fn,
+	uint8_t block_nr, struct gprs_rlcmac_pdch *pdch)
+{
+	struct gprs_rlcmac_tbf *tbf;
+	uint8_t usf = 0x07;
+	uint8_t i, tfi;
+
+	/* select uplink ressource */
+	for (i = 0, tfi = pdch->next_ul_tfi; i < 32;
+	     i++, tfi = (tfi + 1) & 31) {
+		tbf = pdch->ul_tbf[tfi];
+		/* no TBF for this tfi, go next */
+		if (!tbf)
+			continue;
+		/* no UL ressources needed, go next */
+		/* we don't need to give ressources in FINISHED state,
+		 * because we have received all blocks and only poll
+		 * for packet control ack. */
+		if (tbf->state != GPRS_RLCMAC_FLOW)
+			continue;
+
+		/* use this USF */
+		usf = tbf->dir.ul.usf[ts];
+		LOGP(DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: TRX=%d "
+			"TS=%d FN=%d block_nr=%d scheduling USF=%d for "
+			"required uplink ressource of UL TBF=%d\n", trx, ts, fn,
+			block_nr, usf, tfi);
+		/* next TBF to handle ressource is the next one */
+		pdch->next_ul_tfi = (tfi + 1) & 31;
+		break;
+	}
+
+	return usf;
+}
+
+struct msgb *sched_select_ctrl_msg(uint8_t trx, uint8_t ts, uint32_t fn,
+		    uint8_t block_nr, struct gprs_rlcmac_pdch *pdch,
+		    struct gprs_rlcmac_tbf *ul_ass_tbf,
+		    struct gprs_rlcmac_tbf *dl_ass_tbf,
+		    struct gprs_rlcmac_tbf *ul_ack_tbf)
+{
+	struct msgb *msg = NULL;
+	struct gprs_rlcmac_tbf *tbf = NULL;
+
+	/* schedule PACKET UPLINK ASSIGNMENT (1st priority) */
+	if (ul_ass_tbf) {
+		tbf = ul_ass_tbf;
+		msg = gprs_rlcmac_send_packet_uplink_assignment(tbf, fn);
+	}
+	/* schedule PACKET DOWNLINK ASSIGNMENT (2nd priotiry) */
+	if (!msg && dl_ass_tbf) {
+		tbf = dl_ass_tbf;
+		msg = gprs_rlcmac_send_packet_downlink_assignment(tbf, fn);
+	}
+	/* schedule PACKET UPLINK ACK (3rd priority) */
+	if (!msg && ul_ack_tbf) {
+		tbf = ul_ack_tbf;
+		msg = gprs_rlcmac_send_uplink_ack(tbf, fn);
+	}
+	/* any message */
+	if (msg) {
+		LOGP(DRLCMACSCHED, LOGL_DEBUG, "Scheduling control "
+			"message at RTS for %s TBF=%d (TRX=%d, TS=%d)\n",
+			(tbf->direction == GPRS_RLCMAC_UL_TBF)
+					? "UL" : "DL", tbf->tfi, trx, ts);
+		return msg;
+	}
+	/* schedule PACKET PAGING REQUEST */
+	if (llist_empty(&pdch->paging_list))
+		return NULL;
+	msg = gprs_rlcmac_send_packet_paging_request(pdch);
+	if (msg)
+		LOGP(DRLCMACSCHED, LOGL_DEBUG, "Scheduling paging request "
+			"message at RTS for (TRX=%d, TS=%d)\n", trx, ts);
+
+	return msg;
+}
+
+struct msgb *sched_select_downlink(uint8_t trx, uint8_t ts, uint32_t fn,
+		    uint8_t block_nr, struct gprs_rlcmac_pdch *pdch)
+{
+	struct msgb *msg = NULL;
+	struct gprs_rlcmac_tbf *tbf = NULL;
+	uint8_t i, tfi;
+
+	/* select downlink ressource */
+	for (i = 0, tfi = pdch->next_dl_tfi; i < 32;
+	     i++, tfi = (tfi + 1) & 31) {
+		tbf = pdch->dl_tbf[tfi];
+		/* no TBF for this tfi, go next */
+		if (!tbf)
+			continue;
+		/* no DL TBF, go next */
+		if (tbf->direction != GPRS_RLCMAC_DL_TBF)
+			continue;
+		/* no DL ressources needed, go next */
+		if (tbf->state != GPRS_RLCMAC_FLOW
+		 && tbf->state != GPRS_RLCMAC_FINISHED)
+			continue;
+
+		LOGP(DRLCMACSCHED, LOGL_DEBUG, "Scheduling data message at "
+			"RTS for DL TBF=%d (TRX=%d, TS=%d)\n", tfi, trx, ts);
+		/* next TBF to handle ressource is the next one */
+		pdch->next_dl_tfi = (tfi + 1) & 31;
+		/* generate DL data block */
+		msg = gprs_rlcmac_send_data_block_acknowledged(tbf, fn,
+			ts);
+		break;
+	}
+
+	return msg;
+}
+static uint8_t rlcmac_dl_idle[23] = {
+	0x47, /* control without optional header octets, no polling, USF=111 */
+	0x94, /* dummy downlink control message, paging mode 00 */
+	0x2b, /* no persistance level, 7 bits spare pattern */
+	0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b,
+	0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b
+};
+
+struct msgb *sched_dummy(void)
+{
+	struct msgb *msg;
+
+	msg = msgb_alloc(23, "rlcmac_dl_idle");
+	if (!msg)
+		return NULL;
+	memcpy(msgb_put(msg, 23), rlcmac_dl_idle, 23);
+
+	return msg;
+}
+
+int gprs_rlcmac_rcv_rts_block(uint8_t trx, uint8_t ts, uint16_t arfcn,
+        uint32_t fn, uint8_t block_nr)
+{
+	struct gprs_rlcmac_bts *bts = gprs_rlcmac_bts;
+	struct gprs_rlcmac_pdch *pdch;
+	struct gprs_rlcmac_tbf *poll_tbf = NULL, *dl_ass_tbf = NULL,
+		*ul_ass_tbf = NULL, *ul_ack_tbf = NULL;
+	uint8_t usf = 0x7;
+	struct msgb *msg = NULL;
+	uint32_t poll_fn;
+
+	if (trx >= 8 || ts >= 8)
+		return -EINVAL;
+	pdch = &bts->trx[trx].pdch[ts];
+
+	if (!pdch->enable) {
+		LOGP(DRLCMACSCHED, LOGL_ERROR, "Received RTS on disabled PDCH: "
+			"TRX=%d TS=%d\n", trx, ts);
+		return -EIO;
+	}
+
+	/* store last frame number of RTS */
+	pdch->last_rts_fn = fn;
+
+	poll_fn = sched_poll(trx, ts, fn, block_nr, &poll_tbf, &ul_ass_tbf,
+		&dl_ass_tbf, &ul_ack_tbf);
+	/* check uplink ressource for polling */
+	if (poll_tbf)
+		LOGP(DRLCMACSCHED, LOGL_DEBUG, "Received RTS for PDCH: TRX=%d "
+			"TS=%d FN=%d block_nr=%d scheduling free USF for "
+			"polling at FN=%d of %s TFI=%d\n", trx, ts, fn,
+			block_nr, poll_fn,
+			(poll_tbf->direction == GPRS_RLCMAC_UL_TBF)
+				? "UL" : "DL", poll_tbf->tfi);
+		/* use free USF */
+	/* else, we search for uplink ressource */
+	else
+		usf = sched_select_uplink(trx, ts, fn, block_nr, pdch);
+
+	/* Prio 1: select control message */
+	msg = sched_select_ctrl_msg(trx, ts, fn, block_nr, pdch, ul_ass_tbf,
+		dl_ass_tbf, ul_ack_tbf);
+
+	/* Prio 2: select data message for downlink */
+	if (!msg)
+		msg = sched_select_downlink(trx, ts, fn, block_nr, pdch);
+
+	/* Prio 3: send dummy contol message */
+	if (!msg)
+		msg = sched_dummy();
+
+	if (!msg)
+		return -ENOMEM;
+	/* msg is now available */
+
+	/* set USF */
+	msg->data[0] = (msg->data[0] & 0xf8) | usf;
+
+	/* send PDTCH/PACCH to L1 */
+	pcu_l1if_tx_pdtch(msg, trx, ts, arfcn, fn, block_nr);
+
+	return 0;
+}