misc: Add an utility to modulate a RACH burst

The output is only 1sps and needs to be filtered by an RRC filter (0.35)
before transmission.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>

2 files changed, 71 insertions, 1 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index a89e065..08f14ff 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -3,13 +3,18 @@ SUBDIRS = codec l1 sdr
 AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)
 AM_CFLAGS = -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMODSP_CFLAGS)
 
-bin_PROGRAMS = gmr1_rx gmr1_gen_mat gmr1_ambe_decode
+bin_PROGRAMS = gmr1_rx gmr1_rach_gen gmr1_gen_mat gmr1_ambe_decode
 
 gmr1_rx_SOURCES = gmr1_rx.c gsmtap.c
 gmr1_rx_LDADD = $(top_builddir)/src/l1/libgmr1-l1.a \
 		$(top_builddir)/src/sdr/libgmr1-sdr.a \
 		$(LIBOSMOCORE_LIBS) $(LIBOSMODSP_LIBS) $(FFTW3F_LIBS)
 
+gmr1_rach_gen_SOURCES = gmr1_rach_gen.c
+gmr1_rach_gen_LDADD = $(top_builddir)/src/l1/libgmr1-l1.a \
+		      $(top_builddir)/src/sdr/libgmr1-sdr.a \
+		      $(LIBOSMOCORE_LIBS) $(LIBOSMODSP_LIBS) $(FFTW3F_LIBS)
+
 gmr1_gen_mat_SOURCES = gmr1_gen_mat.c
 gmr1_gen_mat_LDADD = $(top_builddir)/src/l1/libgmr1-l1.a \
 		     $(LIBOSMOCORE_LIBS)
diff --git a/src/gmr1_rach_gen.c b/src/gmr1_rach_gen.c
new file mode 100644
index 0000000..de4cf12
--- /dev/null
+++ b/src/gmr1_rach_gen.c
@@ -0,0 +1,65 @@
+/* GMR-1 RACH generation utility */
+
+/* (C) 2015 by Sylvain Munaut <tnt@246tNt.com>
+ * 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 Affero 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 <stdio.h>
+#include <stdlib.h>
+
+#include <osmocom/core/bits.h>
+#include <osmocom/core/utils.h>
+
+#include <osmocom/dsp/cxvec.h>
+
+#include <osmocom/gmr1/l1/rach.h>
+#include <osmocom/gmr1/sdr/defs.h>
+#include <osmocom/gmr1/sdr/pi4cxpsk.h>
+#include <osmocom/gmr1/sdr/nb.h>
+
+int main(int argc, char *argv[])
+{
+	const char *filename;
+	uint8_t sb_mask, rach[18];
+	ubit_t ebits[494];
+	struct osmo_cxvec *burst;
+	int rv;
+
+	/* Check and parse args */
+	if (argc != 4) {
+		fprintf(stderr, "Usage: %s out.cfile sb_mask payload\n", argv[0]);
+		return -1;
+	}
+
+	filename = argv[1];
+	sb_mask = strtoul(argv[2], NULL, 0);
+
+	rv = osmo_hexparse(argv[3], rach, 18);
+	if (rv != 18) {
+		fprintf(stderr, "Invalid payload string\n");
+		return -1;
+	}
+
+	/* Alloc, encode, modulate, save, release */
+	burst = osmo_cxvec_alloc(gmr1_rach_burst.len);
+	gmr1_rach_encode(ebits, rach, sb_mask);
+	gmr1_pi4cxpsk_mod(&gmr1_rach_burst, ebits, 0, burst);
+	osmo_cxvec_dbg_dump(burst, filename);
+	osmo_cxvec_free(burst);
+
+	/* Done */
+	return 0;
+}