1 files changed, 136 insertions, 0 deletions
diff --git a/gr-digital/python/qa_constellation_receiver.py b/gr-digital/python/qa_constellation_receiver.py
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+++ b/gr-digital/python/qa_constellation_receiver.py
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+#!/usr/bin/env python
+#
+# Copyright 2011 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio 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 3, or (at your option)
+# any later version.
+# 
+# GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+# 
+
+import random
+
+from gnuradio import gr, blks2, packet_utils, gr_unittest
+from utils import mod_codes, alignment
+import digital_swig
+from generic_mod_demod import generic_mod, generic_demod
+
+from qa_constellation import tested_constellations, twod_constell
+
+
+# Set a seed so that if errors turn up they are reproducible.
+# 1234 fails
+random.seed(1239)
+
+# TESTING PARAMETERS
+# The number of symbols to test with.
+# We need this many to let the frequency recovery block converge.
+DATA_LENGTH = 200000
+# Test fails if fraction of output that is correct is less than this.
+REQ_CORRECT = 0.8
+
+# CHANNEL PARAMETERS
+NOISE_VOLTAGE = 0.01
+FREQUENCY_OFFSET = 0.01
+TIMING_OFFSET = 1.0
+
+# RECEIVER PARAMETERS
+# Increased from normal default of 0.01 to speed things up.
+FREQ_ALPHA = 0.02
+# Decreased from normal default of 0.1 is required for the constellations
+# with smaller point separations.
+PHASE_ALPHA = 0.02
+
+
+class test_constellation_receiver (gr_unittest.TestCase):
+    
+    # We ignore the first half of the output data since often it takes
+    # a while for the receiver to lock on.
+    ignore_fraction = 0.8
+    seed = 1234
+    max_data_length = DATA_LENGTH * 6
+    max_num_samples = 1000
+    
+    def test_basic(self):
+        """
+        Tests a bunch of different constellations by using generic
+        modulation, a channel, and generic demodulation.  The generic
+        demodulation uses constellation_receiver which is what
+        we're really trying to test.
+        """
+
+        # Assumes not more than 64 points in a constellation
+        # Generates some random input data to use.
+        self.src_data = tuple(
+            [random.randint(0,1) for i in range(0, self.max_data_length)])
+        # Generates some random indices to use for comparing input and
+        # output data (a full comparison is too slow in python).
+        self.indices = alignment.random_sample(
+            self.max_data_length, self.max_num_samples, self.seed)
+
+        for constellation, differential in tested_constellations():
+            # The constellation_receiver doesn't work for constellations
+            # of multple dimensions (i.e. multiple complex numbers to a
+            # single symbol).
+            # That is not implemented since the receiver has no way of
+            # knowing where the beginning of a symbol is.
+            # It also doesn't work for non-differential modulation.
+            if constellation.dimensionality() != 1 or not differential:
+                continue
+            data_length = DATA_LENGTH * constellation.bits_per_symbol()
+            tb = rec_test_tb(constellation, differential,
+                             src_data=self.src_data[:data_length])
+            tb.run()
+            data = tb.dst.data()
+            d1 = tb.src_data[:int(len(tb.src_data)*self.ignore_fraction)]
+            d2 = data[:int(len(data)*self.ignore_fraction)]
+            correct, overlap, offset, indices = alignment.align_sequences(
+                d1, d2, indices=self.indices)
+            self.assertTrue(correct > REQ_CORRECT)
+            
+
+class rec_test_tb (gr.top_block):
+    """
+    Takes a constellation an runs a generic modulation, channel,
+    and generic demodulation.
+    """
+    def __init__(self, constellation, differential,
+                 data_length=None, src_data=None):
+        """
+        constellation -- a constellation object
+        differential -- whether differential encoding is used
+        data_length -- the number of bits of data to use
+        src_data -- a list of the bits to use
+        """
+        super(rec_test_tb, self).__init__()
+        # Transmission Blocks
+        if src_data is None:
+            self.src_data = tuple([random.randint(0,1) for i in range(0, data_length)])
+        else:
+            self.src_data = src_data
+        packer = gr.unpacked_to_packed_bb(1, gr.GR_MSB_FIRST)
+        src = gr.vector_source_b(self.src_data)
+        mod = generic_mod(constellation, differential=differential)
+        # Channel
+        channel = gr.channel_model(NOISE_VOLTAGE, FREQUENCY_OFFSET, TIMING_OFFSET)
+        # Receiver Blocks
+        demod = generic_demod(constellation, differential=differential,
+                              freq_alpha=FREQ_ALPHA,
+                              phase_alpha=PHASE_ALPHA)
+        self.dst = gr.vector_sink_b()
+        self.connect(src, packer, mod, channel, demod, self.dst)
+
+if __name__ == '__main__':
+    gr_unittest.run(test_constellation_receiver, "test_constellation_receiver.xml")