diff --git a/src/osmo-bts-litecell15/lc15_l1_if.c b/src/osmo-bts-litecell15/lc15_l1_if.c
new file mode 100644
index 0000000..2cda5b8
--- /dev/null
+++ b/src/osmo-bts-litecell15/lc15_l1_if.c
@@ -0,0 +1,410 @@
+/* Copyright (C) 2015 by Yves Godin <support@nuranwireless.com>
+ * based on:
+ *     femto_l1_if.c
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 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 Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#include <string.h>
+#include <errno.h>
+
+#include <nrw/litecell15/litecell15.h>
+#include <nrw/litecell15/gsml1prim.h>
+#include <nrw/litecell15/gsml1const.h>
+#include <nrw/litecell15/gsml1types.h>
+
+#include <osmocom/core/gsmtap.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/timer.h>
+#include <lc15_l1_if.h>
+#include <gprs_debug.h>
+#include <pcu_l1_if.h>
+
+extern void *tall_pcu_ctx;
+
+uint32_t l1if_ts_to_hLayer2(uint8_t trx, uint8_t ts)
+{
+	return (ts << 16) | (trx << 24);
+}
+
+/* allocate a msgb containing a GsmL1_Prim_t */
+struct msgb *l1p_msgb_alloc(void)
+{
+	struct msgb *msg = msgb_alloc(sizeof(GsmL1_Prim_t), "l1_prim");
+
+	if (msg)
+		msg->l1h = msgb_put(msg, sizeof(GsmL1_Prim_t));
+
+	return msg;
+}
+
+static int l1if_req_pdch(struct lc15l1_hdl *fl1h, struct msgb *msg)
+{
+	struct osmo_wqueue *wqueue = &fl1h->write_q[MQ_PDTCH_WRITE];
+
+	if (osmo_wqueue_enqueue(wqueue, msg) != 0) {
+		LOGP(DL1IF, LOGL_ERROR, "PDTCH queue full. dropping message.\n");
+		msgb_free(msg);
+	}
+
+	return 0;
+}
+
+static void *prim_init(GsmL1_Prim_t *prim, GsmL1_PrimId_t id, struct lc15l1_hdl *gl1)
+{
+	prim->id = id;
+
+	switch (id) {
+	case GsmL1_PrimId_MphInitReq:
+		//prim->u.mphInitReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphCloseReq:
+		prim->u.mphCloseReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphConnectReq:
+		prim->u.mphConnectReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphDisconnectReq:
+		prim->u.mphDisconnectReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphActivateReq:
+		prim->u.mphActivateReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphDeactivateReq:
+		prim->u.mphDeactivateReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphConfigReq:
+		prim->u.mphConfigReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphMeasureReq:
+		prim->u.mphMeasureReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_MphInitCnf:
+	case GsmL1_PrimId_MphCloseCnf:
+	case GsmL1_PrimId_MphConnectCnf:
+	case GsmL1_PrimId_MphDisconnectCnf:
+	case GsmL1_PrimId_MphActivateCnf:
+	case GsmL1_PrimId_MphDeactivateCnf:
+	case GsmL1_PrimId_MphConfigCnf:
+	case GsmL1_PrimId_MphMeasureCnf:
+		break;
+	case GsmL1_PrimId_MphTimeInd:
+		break;
+	case GsmL1_PrimId_MphSyncInd:
+		break;
+	case GsmL1_PrimId_PhEmptyFrameReq:
+		prim->u.phEmptyFrameReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_PhDataReq:
+		prim->u.phDataReq.hLayer1 = (HANDLE)gl1->hLayer1;
+		break;
+	case GsmL1_PrimId_PhConnectInd:
+		break;
+	case GsmL1_PrimId_PhReadyToSendInd:
+		break;
+	case GsmL1_PrimId_PhDataInd:
+		break;
+	case GsmL1_PrimId_PhRaInd:
+		break;
+	default:
+		LOGP(DL1IF, LOGL_ERROR, "unknown L1 primitive %u\n", id);
+		break;
+	}
+	return &prim->u;
+}
+
+struct sapi_dir {
+	GsmL1_Sapi_t sapi;
+	GsmL1_Dir_t dir;
+};
+
+static const struct sapi_dir pdtch_sapis[] = {
+	{ GsmL1_Sapi_Pdtch,	GsmL1_Dir_TxDownlink },
+	{ GsmL1_Sapi_Pdtch,	GsmL1_Dir_RxUplink },
+	{ GsmL1_Sapi_Ptcch,	GsmL1_Dir_TxDownlink },
+	{ GsmL1_Sapi_Prach,	GsmL1_Dir_RxUplink },
+#if 0
+	{ GsmL1_Sapi_Ptcch,	GsmL1_Dir_RxUplink },
+	{ GsmL1_Sapi_Pacch,	GsmL1_Dir_TxDownlink },
+#endif
+};
+
+
+/* connect PDTCH */
+int l1if_connect_pdch(void *obj, uint8_t ts)
+{
+	struct lc15l1_hdl *fl1h = obj;
+	struct msgb *msg = l1p_msgb_alloc();
+	GsmL1_MphConnectReq_t *cr;
+
+	cr = prim_init(msgb_l1prim(msg), GsmL1_PrimId_MphConnectReq, fl1h);
+	cr->u8Tn = ts;
+	cr->logChComb = GsmL1_LogChComb_XIII;
+
+	return l1if_req_pdch(fl1h, msg);
+}
+
+static int handle_ph_readytosend_ind(struct lc15l1_hdl *fl1h,
+				     GsmL1_PhReadyToSendInd_t *rts_ind)
+{
+	struct gsm_time g_time;
+	int rc = 0;
+
+	gsm_fn2gsmtime(&g_time, rts_ind->u32Fn);
+
+	DEBUGP(DL1IF, "Rx PH-RTS.ind %02u/%02u/%02u SAPI=%s\n",
+		g_time.t1, g_time.t2, g_time.t3,
+		get_value_string(lc15bts_l1sapi_names, rts_ind->sapi));
+
+	switch (rts_ind->sapi) {
+	case GsmL1_Sapi_Pdtch:
+	case GsmL1_Sapi_Pacch:
+		rc = pcu_rx_rts_req_pdtch(fl1h->trx_no, rts_ind->u8Tn,
+			rts_ind->u16Arfcn, rts_ind->u32Fn, rts_ind->u8BlockNbr);
+	case GsmL1_Sapi_Ptcch:
+		// FIXME
+	default:
+		break;
+	}
+
+	return rc;
+}
+
+static void get_meas(struct pcu_l1_meas *meas, const GsmL1_MeasParam_t *l1_meas)
+{
+	meas->rssi = (int8_t) (l1_meas->fRssi);
+	meas->have_rssi = 1;
+	meas->ber  = (uint8_t) (l1_meas->fBer * 100);
+	meas->have_ber = 1;
+	meas->bto  = (int16_t) (l1_meas->i16BurstTiming);
+	meas->have_bto = 1;
+	meas->link_qual  = (int16_t) (l1_meas->fLinkQuality);
+	meas->have_link_qual = 1;
+}
+
+static int handle_ph_data_ind(struct lc15l1_hdl *fl1h,
+	GsmL1_PhDataInd_t *data_ind, struct msgb *l1p_msg)
+{
+	int rc = 0;
+	struct pcu_l1_meas meas = {0};
+
+	DEBUGP(DL1IF, "Rx PH-DATA.ind %s (hL2 %08x): %s\n",
+		get_value_string(lc15bts_l1sapi_names, data_ind->sapi),
+		data_ind->hLayer2,
+		osmo_hexdump(data_ind->msgUnitParam.u8Buffer,
+			     data_ind->msgUnitParam.u8Size));
+
+	/*
+	 * TODO: Add proper bad frame handling here. This could be used
+	 * to switch the used CS. Avoid a crash with the PCU right now
+	 * feed "0 - 1" amount of data.
+	 */
+	if (data_ind->msgUnitParam.u8Size == 0)
+		return -1;
+
+	gsmtap_send(fl1h->gsmtap, data_ind->u16Arfcn | GSMTAP_ARFCN_F_UPLINK,
+			data_ind->u8Tn, GSMTAP_CHANNEL_PACCH, 0,
+			data_ind->u32Fn, 0, 0, data_ind->msgUnitParam.u8Buffer+1,
+			data_ind->msgUnitParam.u8Size-1);
+
+	get_meas(&meas, &data_ind->measParam);
+
+	switch (data_ind->sapi) {
+	case GsmL1_Sapi_Pdtch:
+	case GsmL1_Sapi_Pacch:
+		/* drop incomplete UL block */
+		if (data_ind->msgUnitParam.u8Buffer[0]
+			!= GsmL1_PdtchPlType_Full)
+			break;
+		/* PDTCH / PACCH frame handling */
+		pcu_rx_data_ind_pdtch(fl1h->trx_no, data_ind->u8Tn,
+			data_ind->msgUnitParam.u8Buffer + 1,
+			data_ind->msgUnitParam.u8Size - 1,
+			data_ind->u32Fn,
+			&meas);
+		break;
+	case GsmL1_Sapi_Ptcch:
+		// FIXME
+		break;
+	default:
+		LOGP(DL1IF, LOGL_NOTICE, "Rx PH-DATA.ind for unknown L1 SAPI %s\n",
+			get_value_string(lc15bts_l1sapi_names, data_ind->sapi));
+		break;
+	}
+
+	return rc;
+}
+
+#define MIN_QUAL_RACH	5.0f
+
+static int handle_ph_ra_ind(struct lc15l1_hdl *fl1h, GsmL1_PhRaInd_t *ra_ind)
+{
+	uint8_t acc_delay;
+
+	if (ra_ind->measParam.fLinkQuality < MIN_QUAL_RACH)
+		return 0;
+
+	DEBUGP(DL1IF, "Rx PH-RA.ind");
+
+	/* check for under/overflow / sign */
+	if (ra_ind->measParam.i16BurstTiming < 0)
+		acc_delay = 0;
+	else
+		acc_delay = ra_ind->measParam.i16BurstTiming >> 2;
+
+	LOGP(DL1IF, LOGL_NOTICE, "got (P)RACH request, TA = %u (ignored)\n",
+		acc_delay);
+
+#warning "The (P)RACH request is just dropped here"
+
+#if 0
+	if (acc_delay > bts->max_ta) {
+		LOGP(DL1C, LOGL_INFO, "ignoring RACH request %u > max_ta(%u)\n",
+		     acc_delay, btsb->max_ta);
+		return 0;
+	}
+#endif
+
+	return 0;
+}
+
+
+/* handle any random indication from the L1 */
+int l1if_handle_l1prim(int wq, struct lc15l1_hdl *fl1h, struct msgb *msg)
+{
+	GsmL1_Prim_t *l1p = msgb_l1prim(msg);
+	int rc = 0;
+
+	LOGP(DL1IF, LOGL_DEBUG, "Rx L1 prim %s on queue %d\n",
+		get_value_string(lc15bts_l1prim_names, l1p->id), wq);
+
+	switch (l1p->id) {
+#if 0
+	case GsmL1_PrimId_MphTimeInd:
+		rc = handle_mph_time_ind(fl1h, &l1p->u.mphTimeInd);
+		break;
+	case GsmL1_PrimId_MphSyncInd:
+		break;
+	case GsmL1_PrimId_PhConnectInd:
+		break;
+#endif
+	case GsmL1_PrimId_PhReadyToSendInd:
+		rc = handle_ph_readytosend_ind(fl1h, &l1p->u.phReadyToSendInd);
+		break;
+	case GsmL1_PrimId_PhDataInd:
+		rc = handle_ph_data_ind(fl1h, &l1p->u.phDataInd, msg);
+		break;
+	case GsmL1_PrimId_PhRaInd:
+		rc = handle_ph_ra_ind(fl1h, &l1p->u.phRaInd);
+		break;
+	default:
+		break;
+	}
+
+	msgb_free(msg);
+
+	return rc;
+}
+
+int l1if_handle_sysprim(struct lc15l1_hdl *fl1h, struct msgb *msg)
+{
+	return -ENOTSUP;
+}
+
+/* send packet data request to L1 */
+int l1if_pdch_req(void *obj, uint8_t ts, int is_ptcch, uint32_t fn,
+	uint16_t arfcn, uint8_t block_nr, uint8_t *data, uint8_t len)
+{
+	struct lc15l1_hdl *fl1h = obj;
+	struct msgb *msg;
+	GsmL1_Prim_t *l1p;
+	GsmL1_PhDataReq_t *data_req;
+	GsmL1_MsgUnitParam_t *msu_param;
+	struct gsm_time g_time;
+
+	gsm_fn2gsmtime(&g_time, fn);
+
+	DEBUGP(DL1IF, "TX packet data %02u/%02u/%02u is_ptcch=%d ts=%d "
+		"block_nr=%d, arfcn=%d, len=%d\n", g_time.t1, g_time.t2,
+		g_time.t3, is_ptcch, ts, block_nr, arfcn, len);
+
+	msg = l1p_msgb_alloc();
+	l1p = msgb_l1prim(msg);
+	l1p->id = GsmL1_PrimId_PhDataReq;
+	data_req = &l1p->u.phDataReq;
+	data_req->hLayer1 = (HANDLE)fl1h->hLayer1;
+	data_req->sapi = (is_ptcch) ? GsmL1_Sapi_Ptcch : GsmL1_Sapi_Pdtch;
+	data_req->subCh = GsmL1_SubCh_NA;
+	data_req->u8BlockNbr = block_nr;
+	data_req->u8Tn = ts;
+	data_req->u32Fn = fn;
+	msu_param = &data_req->msgUnitParam;
+	msu_param->u8Size = len;
+	memcpy(msu_param->u8Buffer, data, len);
+
+	gsmtap_send(fl1h->gsmtap, arfcn, data_req->u8Tn, GSMTAP_CHANNEL_PACCH,
+			0, data_req->u32Fn, 0, 0,
+			data_req->msgUnitParam.u8Buffer,
+			data_req->msgUnitParam.u8Size);
+
+
+	/* transmit */
+	if (osmo_wqueue_enqueue(&fl1h->write_q[MQ_PDTCH_WRITE], msg) != 0) {
+		LOGP(DL1IF, LOGL_ERROR, "PDTCH queue full. dropping message.\n");
+		msgb_free(msg);
+	}
+
+	return 0;
+}
+
+void *l1if_open_pdch(uint8_t trx_no, uint32_t hlayer1)
+{
+	struct lc15l1_hdl *fl1h;
+	int rc;
+
+	fl1h = talloc_zero(tall_pcu_ctx, struct lc15l1_hdl);
+	if (!fl1h)
+		return NULL;
+
+	fl1h->hLayer1 = hlayer1;
+	fl1h->trx_no = trx_no;
+	/* hardware queues are numbered starting from 1 */
+	fl1h->hw_info.trx_nr = trx_no + 1;
+
+	DEBUGP(DL1IF, "PCU: Using TRX HW#%u\n", fl1h->hw_info.trx_nr);
+
+	rc = l1if_transport_open(MQ_PDTCH_WRITE, fl1h);
+	if (rc < 0) {
+		talloc_free(fl1h);
+		return NULL;
+	}
+
+	fl1h->gsmtap = gsmtap_source_init("localhost", GSMTAP_UDP_PORT, 1);
+	if (fl1h->gsmtap)
+		gsmtap_source_add_sink(fl1h->gsmtap);
+
+	return fl1h;
+}
+
+int l1if_close_pdch(void *obj)
+{
+	struct lc15l1_hdl *fl1h = obj;
+	if (fl1h)
+		l1if_transport_close(MQ_PDTCH_WRITE, fl1h);
+	talloc_free(fl1h);
+	return 0;
+}
+