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#!/usr/bin/env python
#
# Copyright 2004,2010 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 math
from gnuradio import gr, gr_unittest, blks2
# It's pretty ugly that we can't import trellis from gnuradio in this test
# but because it runs on the non-installed python code it's all a mess.
import trellis
fsm_args = {"awgn1o2_4": (2, 4, 4,
(0, 2, 0, 2, 1, 3, 1, 3),
(0, 3, 3, 0, 1, 2, 2, 1),
),
"rep2": (2, 1, 4, (0, 0), (0, 3)),
"nothing": (2, 1, 2, (0, 0), (0, 1)),
}
constells = {2: blks2.bpsk_constellation(),
4: blks2.qpsk_constellation(),
}
class test_trellis (gr_unittest.TestCase):
def test_001_fsm (self):
f = trellis.fsm(*fsm_args["awgn1o2_4"])
self.assertEqual(fsm_args["awgn1o2_4"],(f.I(),f.S(),f.O(),f.NS(),f.OS()))
def test_002_fsm (self):
f = trellis.fsm(*fsm_args["awgn1o2_4"])
g = trellis.fsm(f)
self.assertEqual((g.I(),g.S(),g.O(),g.NS(),g.OS()),(f.I(),f.S(),f.O(),f.NS(),f.OS()))
def test_003_fsm (self):
f = trellis.fsm("awgn1o2_4.fsm")
self.assertEqual(fsm_args["awgn1o2_4"],(f.I(),f.S(),f.O(),f.NS(),f.OS()))
def test_004_fsm(self):
""" Test to make sure fsm works with a single state fsm."""
# Just checking that it initializes properly.
f = trellis.fsm(*fsm_args["rep2"])
def test_001_interleaver (self):
K = 5
IN = (1,2,3,4,0)
DIN = (4,0,1,2,3)
i = trellis.interleaver(K,IN)
self.assertEqual((K,IN,DIN),(i.K(),i.INTER(),i.DEINTER()))
def test_001_viterbi(self):
"""
Runs some coding/decoding tests with a few different FSM
specs.
"""
for name, args in fsm_args.items():
constellation = constells[args[2]]
fsms = trellis.fsm(*args)
noise = 0.1
tb = trellis_tb(constellation, fsms, noise)
tb.run()
# Make sure all packets succesfully transmitted.
self.assertEqual(tb.dst.ntotal(), tb.dst.nright())
class trellis_tb(gr.top_block):
"""
A simple top block for use testing gr-trellis.
"""
def __init__(self, constellation, f, N0=0.25, seed=-666L):
"""
constellation - a constellation object used for modulation.
f - a finite state machine specification used for coding.
N0 - noise level
seed - random seed
"""
super(trellis_tb, self).__init__()
# packet size in bits (make it multiple of 16 so it can be packed in a short)
packet_size = 1024*16
# bits per FSM input symbol
bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol
# packet size in trellis steps
K = packet_size/bitspersymbol
# TX
src = gr.lfsr_32k_source_s()
# packet size in shorts
src_head = gr.head (gr.sizeof_short, packet_size/16)
# unpack shorts to symbols compatible with the FSM input cardinality
s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol, gr.GR_MSB_FIRST)
# initial FSM state = 0
enc = trellis.encoder_ss(f, 0)
mod = gr.chunks_to_symbols_sc(constellation.points(), 1)
# CHANNEL
add = gr.add_cc()
noise = gr.noise_source_c(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed)
# RX
# data preprocessing to generate metrics for Viterbi
metrics = trellis.constellation_metrics_cf(constellation.base(), trellis.TRELLIS_EUCLIDEAN)
# Put -1 if the Initial/Final states are not set.
va = trellis.viterbi_s(f, K, 0, -1)
# pack FSM input symbols to shorts
fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol, gr.GR_MSB_FIRST)
# check the output
self.dst = gr.check_lfsr_32k_s()
self.connect (src, src_head, s2fsmi, enc, mod)
self.connect (mod, (add, 0))
self.connect (noise, (add, 1))
self.connect (add, metrics, va, fsmi2s, self.dst)
if __name__ == '__main__':
gr_unittest.run(test_trellis, "test_trellis.xml")
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