def test_002_t(self):
"""Encoder to Decoder - noisy BPSK w/ soft constellation de-mapper"""
# Parameters
N = 18444
K = 6144
pct_en = False
n_ite = 6
M = 2
snr_db = SNR_DB
max_len = 10 * K
flip_llrs = False
sym_rate = 2 * 156250
# NOTE: The soft decoder block outputs positive LLR if bit "1" is more
# likely, and negative LLR otherwise (bit = 0). That is, the soft
# de-mapper's convention is the oposite of the one adopted in the Turbo
# Decoder. To compensate that, we choose to flip the LLRs (multiply them
# by "-1") inside the decoder wrapper.
# Constants
noise_v = 1 / math.sqrt((10**(float(snr_db) / 10)))
rndm = random.Random()
# Input data
in_vec = tuple([rndm.randint(0, 1) for i in range(0, max_len)])
# Flowgraph
src = blocks.vector_source_b(in_vec)
enc = blocksattx.turbo_encoder(K, pct_en)
const = digital.constellation_bpsk().base()
cmap = digital.chunks_to_symbols_bc(const.points())
nadder = blocks.add_cc()
noise = analog.noise_source_c(analog.GR_GAUSSIAN, noise_v, 0)
cdemap = blocksat.soft_decoder_cf(M, noise_v)
dec = blocksat.turbo_decoder(K, pct_en, n_ite, flip_llrs)
snk = blocks.vector_sink_b()
snk_sym = blocks.vector_sink_c()
snk_llr = blocks.vector_sink_f()
self.tb.connect(src, enc, cmap)
self.tb.connect(cmap, (nadder, 0))
self.tb.connect(noise, (nadder, 1))
self.tb.connect(nadder, cdemap, dec, snk)
self.tb.connect(cmap, snk_sym)
self.tb.connect(cdemap, snk_llr)
self.tb.run()
# Collect results
out_vec = snk.data()
llrs = snk_llr.data()
syms = snk_sym.data()
diff = array(in_vec) - array(out_vec)
err = [0 if i == 0 else 1 for i in diff]
self.dump(const.points(), in_vec, syms, llrs, out_vec)
print('Number of errors: %d' % (sum(err)))
# Check results
self.assertEqual(sum(err), 0)
def test_003_t(self):
"""Encoder to Decoder - noisy QPSK w/ soft constellation de-mapper"""
# Parameters
N = 18444
K = 6144
pct_en = False
n_ite = 6
M = 4
snr_db = SNR_DB
max_len = 10 * K
flip_llrs = False
sym_rate = 2 * 156250
# NOTE: just like in the previous example, flipping of the LLRs is
# necessary here.
# Constants
noise_v = 1 / math.sqrt((10**(float(snr_db) / 10)))
rndm = random.Random()
# Input data
in_vec = tuple([rndm.randint(0, 1) for i in range(0, max_len)])
# Flowgraph
src = blocks.vector_source_b(in_vec)
enc = blocksattx.turbo_encoder(K, pct_en)
pack = blocks.repack_bits_bb(1, 2, "", False, gr.GR_MSB_FIRST)
const = digital.constellation_qpsk().base()
cmap = digital.chunks_to_symbols_bc(const.points())
nadder = blocks.add_cc()
noise = analog.noise_source_c(analog.GR_GAUSSIAN, noise_v, 0)
cdemap = blocksat.soft_decoder_cf(M, noise_v)
dec = blocksat.turbo_decoder(K, pct_en, n_ite, flip_llrs)
snk = blocks.vector_sink_b()
snk_sym = blocks.vector_sink_c()
snk_llr = blocks.vector_sink_f()
self.tb.connect(src, enc, pack, cmap)
self.tb.connect(cmap, (nadder, 0))
self.tb.connect(noise, (nadder, 1))
self.tb.connect(nadder, cdemap, dec, snk)
self.tb.connect(cmap, snk_sym)
self.tb.connect(cdemap, snk_llr)
self.tb.run()
# Collect results
out_vec = snk.data()
llrs = snk_llr.data()
syms = snk_sym.data()
diff = array(in_vec) - array(out_vec)
err = [0 if i == 0 else 1 for i in diff]
self.dump(const.points(), in_vec, syms, llrs, out_vec)
print('Number of errors: %d' % (sum(err)))
# Check results
self.assertEqual(sum(err), 0)
def test_001_t(self):
"""QPSK points in each quadrant"""
# Parameters
M = 4
N0 = 1.0
symbol = ((-0.5 - 0.5j), (0.5 - 0.5j), (-0.5 + 0.5j), (0.5 + 0.5j))
# Flowgraph
src = blocks.vector_source_c(symbol)
soft_decoder = blocksat.soft_decoder_cf(M, N0)
snk = blocks.vector_sink_f()
self.tb.connect(src, soft_decoder, snk)
self.tb.run()
# Check data
llrs = snk.data()
expected_llrs = (1.4142, 1.4142, 1.4142, -1.4142, -1.4142, 1.4142,
-1.4142, -1.4142)
print(llrs)
self.assertFloatTuplesAlmostEqual(llrs, expected_llrs, places=4)
def test_002_t(self):
"""Decoding of noisy QPSK symbols"""
# Parameters
M = 4
N0 = 1.0
max_len = 50
snr_db = 20
# Constants
rndm = random.Random()
noise_v = 1 / math.sqrt((10**(float(snr_db) / 10)))
in_vec = tuple([rndm.randint(0, 1) for i in range(0, max_len)])
# Flowgraph
src = blocks.vector_source_b(in_vec)
pack = blocks.repack_bits_bb(1, 2, "", False, gr.GR_MSB_FIRST)
const = digital.constellation_qpsk().base()
cmap = digital.chunks_to_symbols_bc(const.points())
nadder = blocks.add_cc()
noise = analog.noise_source_c(analog.GR_GAUSSIAN, noise_v, 0)
soft_decoder = blocksat.soft_decoder_cf(M, N0)
slicer = digital.binary_slicer_fb()
inverter = digital.map_bb([1, 0])
snk = blocks.vector_sink_b()
snk_llr = blocks.vector_sink_f()
self.tb.connect(src, pack, cmap)
self.tb.connect(cmap, (nadder, 0))
self.tb.connect(noise, (nadder, 1))
self.tb.connect(nadder, soft_decoder, slicer, inverter, snk)
self.tb.connect(soft_decoder, snk_llr)
self.tb.run()
# check data
dec_vec = snk.data()
llrs = snk_llr.data()
print(llrs)
print(in_vec)
print(dec_vec)
self.assertFloatTuplesAlmostEqual(in_vec, dec_vec, places=4)