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Diffstat (limited to 'gr-digital/python/qa_constellation.py')
| -rwxr-xr-x | gr-digital/python/qa_constellation.py | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/gr-digital/python/qa_constellation.py b/gr-digital/python/qa_constellation.py new file mode 100755 index 000000000..02afb8d2d --- /dev/null +++ b/gr-digital/python/qa_constellation.py @@ -0,0 +1,205 @@ +#!/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 cmath import exp, pi, log + +from gnuradio import gr, gr_unittest, blks2 +from utils import mod_codes +import digital_swig + +# import from local folder +import psk2 +import qam + +tested_mod_codes = (mod_codes.NO_CODE, mod_codes.GRAY_CODE) + +# A list of the constellations to test. +# Each constellation is given by a 3-tuple. +# First item is a function to generate the constellation +# Second item is a dictionary of arguments for function with lists of +# possible values. +# Third item is whether differential encoding should be tested. +# Fourth item is the name of the argument to constructor that specifices +# whether differential encoding is used. + +def twod_constell(): + """ + + """ + points = ((1+0j), (0+1j), + (-1+0j), (0-1j)) + rot_sym = 2 + dim = 2 + return digital_swig.constellation_calcdist(points, [], rot_sym, dim) + +def threed_constell(): + oned_points = ((1+0j), (0+1j), (-1+0j), (0-1j)) + points = [] + r4 = range(0, 4) + for ia in r4: + for ib in r4: + for ic in r4: + points += [oned_points[ia], oned_points[ib], oned_points[ic]] + rot_sym = 4 + dim = 3 + return digital_swig.constellation_calcdist(points, [], rot_sym, dim) + +tested_constellation_info = ( + (psk2.psk_constellation, + {'m': (2, 4, 8, 16, 32, 64), + 'mod_code': tested_mod_codes, }, + True, None), + (digital_swig.constellation_bpsk, {}, True, None), + # No differential testing for qpsk because it is gray-coded. + # This is because soft decision making is simpler if we can assume + # gray coding. + (digital_swig.constellation_qpsk, {}, False, None), + (digital_swig.constellation_8psk, {}, False, None), + (twod_constell, {}, True, None), + (threed_constell, {}, True, None), + ) + +def tested_constellations(): + """ + Generator to produce (constellation, differential) tuples for testing purposes. + """ + for constructor, poss_args, differential, diff_argname in tested_constellation_info: + if differential: + diff_poss = (True, False) + else: + diff_poss = (False,) + poss_args = [[argname, argvalues, 0] for argname, argvalues in poss_args.items()] + for current_diff in diff_poss: + # Add an index into args to keep track of current position in argvalues + while True: + current_args = dict([(argname, argvalues[argindex]) + for argname, argvalues, argindex in poss_args]) + if diff_argname is not None: + current_args[diff_argname] = current_diff + constellation = constructor(**current_args) + yield (constellation, current_diff) + for this_poss_arg in poss_args: + argname, argvalues, argindex = this_poss_arg + if argindex < len(argvalues) - 1: + this_poss_arg[2] += 1 + break + else: + this_poss_arg[2] = 0 + if sum([argindex for argname, argvalues, argindex in poss_args]) == 0: + break + + +class test_constellation (gr_unittest.TestCase): + + src_length = 256 + + def setUp(self): + # Generate a list of random bits. + self.src_data = tuple([random.randint(0,1) for i in range(0, self.src_length)]) + + def tearDown(self): + pass + + def test_hard_decision(self): + for constellation, differential in tested_constellations(): + if differential: + rs = constellation.rotational_symmetry() + rotations = [exp(i*2*pi*(0+1j)/rs) for i in range(0, rs)] + else: + rotations = [None] + for rotation in rotations: + src = gr.vector_source_b(self.src_data) + content = mod_demod(constellation, differential, rotation) + dst = gr.vector_sink_b() + self.tb = gr.top_block() + self.tb.connect(src, content, dst) + self.tb.run() + data = dst.data() + # Don't worry about cut off data for now. + first = constellation.bits_per_symbol() + self.assertEqual (self.src_data[first:len(data)], data[first:]) + + +class mod_demod(gr.hier_block2): + def __init__(self, constellation, differential, rotation): + if constellation.arity() > 256: + # If this becomes limiting some of the blocks should be generalised so that they can work + # with shorts and ints as well as chars. + raise ValueError("Constellation cannot contain more than 256 points.") + + gr.hier_block2.__init__(self, "mod_demod", + gr.io_signature(1, 1, gr.sizeof_char), # Input signature + gr.io_signature(1, 1, gr.sizeof_char)) # Output signature + + arity = constellation.arity() + + # TX + self.constellation = constellation + self.differential = differential + self.blocks = [self] + # We expect a stream of unpacked bits. + # First step is to pack them. + self.blocks.append( + gr.unpacked_to_packed_bb(1, gr.GR_MSB_FIRST)) + # Second step we unpack them such that we have k bits in each byte where + # each constellation symbol hold k bits. + self.blocks.append( + gr.packed_to_unpacked_bb(self.constellation.bits_per_symbol(), + gr.GR_MSB_FIRST)) + # Apply any pre-differential coding + # Gray-coding is done here if we're also using differential coding. + if self.constellation.apply_pre_diff_code(): + self.blocks.append(gr.map_bb(self.constellation.pre_diff_code())) + # Differential encoding. + if self.differential: + self.blocks.append(gr.diff_encoder_bb(arity)) + # Convert to constellation symbols. + self.blocks.append(gr.chunks_to_symbols_bc(self.constellation.points(), self.constellation.dimensionality())) + # CHANNEL + # Channel just consists of a rotation to check differential coding. + if rotation is not None: + self.blocks.append(gr.multiply_const_cc(rotation)) + + # RX + # Convert the constellation symbols back to binary values. + self.blocks.append(digital_swig.constellation_decoder_cb(self.constellation.base())) + # Differential decoding. + if self.differential: + self.blocks.append(gr.diff_decoder_bb(arity)) + # Decode any pre-differential coding. + if self.constellation.apply_pre_diff_code(): + self.blocks.append(gr.map_bb( + mod_codes.invert_code(self.constellation.pre_diff_code()))) + # unpack the k bit vector into a stream of bits + self.blocks.append(gr.unpack_k_bits_bb( + self.constellation.bits_per_symbol())) + # connect to block output + check_index = len(self.blocks) + self.blocks = self.blocks[:check_index] + self.blocks.append(self) + + self.connect(*self.blocks) + + +if __name__ == '__main__': + gr_unittest.run(test_constellation, "test_constellation.xml") |