utils: Import some utilities to actually receive and process signals

This includes an utility to easily identify what ARFCNs are visible in
a given capture made by osmocom_fft and a utility to do live captures
using GNURadio.

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

utils/gmr1_process_recording.py

@@ -0,0 +1,118 @@
+#!/usr/bin/env python
+
+#
+# (C) 2011-2019 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/>.
+#
+
+from collections import namedtuple
+
+import datetime
+import os
+import sys
+import re
+
+
+EXEC_GMR1_DEMOD = 'gmr1_rx_live'
+EXEC_GMR1_SPLIT = 'gmr1_rx_sdr.py'
+
+
+
+CHAN_BW = 31.25e3
+
+Recording = namedtuple('Recording', 'center samplerate timestamp')
+
+def parse_filename(fn):
+	m = re.match('^.*-f([0-9\.e+-]*)-s([0-9\.e+-]*)-t([0-9]{14})\.cfile$', fn)
+	if not m:
+		return m
+
+	return Recording(
+		float(m.group(1)),
+		float(m.group(2)),
+		datetime.datetime.strptime(m.group(3), '%Y%m%d%H%M%S'),
+	)
+
+def arfcn_to_freq(arfcn, band='L'):
+	base = {
+		'L': 1525e6,
+		'S': 2170e6 + 15.625e3,
+	}
+	return base[band] + 31.25e3 * arfcn
+
+def arfcn_fifo(arfcn):
+	return "/tmp/arfcn_%d.cfile" % arfcn
+
+
+def main(argv0, capture_fn):
+
+	# Parse filename
+	p = parse_filename(capture_fn)
+
+	# Derive upper and lower band
+	ll = p.center - p.samplerate / 2 + CHAN_BW
+	ul = p.center + p.samplerate / 2 - CHAN_BW
+
+	# Select band
+	band = 'S' if ul > 2e9 else 'L'
+	n_arfcns = {
+		'L': 1087,
+		'S': 960,
+	}
+
+	# List all visible arfcns
+	visible_arfcns = [x for x in range(0,n_arfcns[band]+1) if ll <= arfcn_to_freq(x, band) <= ul]
+
+	# Create all FIFOs
+	#for arfcn in visible_arfcns:
+	#	if os.path.exists(arfcn_fifo(arfcn)):
+	#		print "Output FIFO already exists, aborting !"
+	#		return -1
+
+	#for arfcn in visible_arfcns:
+	#	os.mkfifo(arfcn_fifo(arfcn))
+
+	#
+	exec_split = [
+		EXEC_GMR1_SPLIT,
+		'-s', '%f' % p.samplerate,
+		'-f', '%f' % p.center,
+		'-B', band,
+		'--args', 'file=%s,freq=%f,rate=%f,throttle=false,repeat=false' % (capture_fn, p.center, p.samplerate),
+	]
+
+	for arfcn in visible_arfcns:
+		exec_split.extend(['-a', '%d' % arfcn])
+
+	print ' '.join(exec_split)
+
+	#
+	exec_rx = [
+		EXEC_GMR1_DEMOD, '4',
+	]
+
+	for arfcn in visible_arfcns:
+		exec_rx.append('%d:%s' % (arfcn, arfcn_fifo(arfcn)))
+
+	print ' '.join(exec_rx)
+
+	# Cleanup all FIFOs
+	#for arfcn in visible_arfcns:
+	#	os.unlink(arfcn_fifo(arfcn))
+
+
+if __name__ == '__main__':
+	main(*sys.argv)