def test_link_performance():
# Apply link_performance to SISO QPSK and AWGN channel
QPSK = QAMModem(4)
def receiver(y, h, constellation):
return QPSK.demodulate(y, 'hard')
model = LinkModel(QPSK.modulate, SISOFlatChannel(fading_param=(1 + 0j, 0)), receiver,
QPSK.num_bits_symbol, QPSK.constellation, QPSK.Es)
BERs = link_performance(model, range(0, 9, 2), 600e4, 600)
desired = erfc(sqrt(10**(arange(0, 9, 2) / 10) / 2)) / 2
assert_allclose(BERs, desired, rtol=0.25,
err_msg='Wrong performance for SISO QPSK and AWGN channel')
# Apply link_performance to MIMO 16QAM and 4x4 Rayleigh channel
QAM16 = QAMModem(16)
RayleighChannel = MIMOFlatChannel(4, 4)
RayleighChannel.uncorr_rayleigh_fading(complex)
def receiver(y, h, constellation):
return QAM16.demodulate(kbest(y, h, constellation, 16), 'hard')
model = LinkModel(QAM16.modulate, RayleighChannel, receiver,
QAM16.num_bits_symbol, QAM16.constellation, QAM16.Es)
SNRs = arange(0, 21, 5) + 10 * log10(QAM16.num_bits_symbol)
BERs = link_performance(model, SNRs, 600e4, 600)
desired = (2e-1, 1e-1, 3e-2, 2e-3, 4e-5) # From reference
assert_allclose(BERs, desired, rtol=1.25,
err_msg='Wrong performance for MIMO 16QAM and 4x4 Rayleigh channel')
def test_wifi80211_mimo_channel():
seed(17121996)
# Apply link_performance to MIMO 16QAM and 4x4 Rayleigh channel
wifi80211 = Wifi80211(3)
RayleighChannel = MIMOFlatChannel(4, 4)
RayleighChannel.uncorr_rayleigh_fading(complex)
modem = wifi80211.get_modem()
def receiver(y, h, constellation, noise_var):
return modem.demodulate(kbest(y, h, constellation, 16), 'hard')
BERs = wifi80211.link_performance(RayleighChannel,
arange(0, 21, 5) +
10 * log10(modem.num_bits_symbol),
10**4,
600,
receiver=receiver)[0]
desired = (0.535, 0.508, 0.521, 0.554, 0.475) # From previous test
assert_allclose(
BERs,
desired,
rtol=1.25,
err_msg='Wrong performance for MIMO 16QAM and 4x4 Rayleigh channel')
def do(self, nb_tx, nb_rx):
# Set seed
seed(17121996)
def check_chan_gain(mod, chan):
msg = choice(mod, self.msg_length)
chan.propagate(msg)
P_msg = signal_power(msg)
P_unnoisy = signal_power(chan.unnoisy_output)
assert_allclose(P_unnoisy, P_msg * chan.nb_tx, rtol=0.2,
err_msg='Channel add or remove energy')
def expo_correlation(t, r):
# Construct the exponent matrix
expo_tx = fromiter((j - i for i in range(chan.nb_tx) for j in range(chan.nb_tx)), int, chan.nb_tx ** 2)
expo_rx = fromiter((j - i for i in range(chan.nb_rx) for j in range(chan.nb_rx)), int, chan.nb_rx ** 2)
# Reshape
expo_tx = expo_tx.reshape(chan.nb_tx, chan.nb_tx)
expo_rx = expo_rx.reshape(chan.nb_rx, chan.nb_rx)
return t ** expo_tx, r ** expo_rx
def check_correlation(chan, Rt, Rr):
nb_ant = chan.nb_tx * chan.nb_rx
Rdes = kron(Rt, Rr)
H = chan.channel_gains
Ract = zeros_like(Rdes)
for i in range(len(H)):
Ract += H[i].T.reshape(nb_ant, 1).dot(H[i].T.reshape(1, nb_ant).conj())
Ract /= len(H)
assert_allclose(Rdes, Ract, atol=0.05,
err_msg='Wrong correlation matrix')
# Test value checking in constructor construction
with assert_raises(ValueError):
MIMOFlatChannel(nb_tx, nb_tx, 0, (ones((nb_tx, nb_tx)), ones((nb_tx, nb_tx)), ones((nb_rx, nb_rx))))
chan = MIMOFlatChannel(nb_tx, nb_rx, 0)
prod_nb = nb_tx * nb_rx
# Test on real channel
for mod in self.real_mods:
# Test value checking after construction
with assert_raises(ValueError):
chan.fading_param = (ones((nb_tx, nb_tx)), ones((nb_tx, nb_tx)), ones((nb_rx, nb_rx)))
# Test with Rayleigh fading
chan.fading_param = (zeros((nb_rx, nb_tx)), identity(nb_tx), identity(nb_rx))
check_chan_gain(mod, chan)
# Test with rician fading
mean = randn(nb_rx, nb_tx)
mean *= sqrt(prod_nb * 0.75 / einsum('ij,ij->', absolute(mean), absolute(mean)))
Rt = self.random_SDP_matrix(nb_tx) * sqrt(prod_nb) * 0.5
Rr = self.random_SDP_matrix(nb_rx) * sqrt(prod_nb) * 0.5
chan.fading_param = (mean, Rt, Rr)
check_chan_gain(mod, chan)
# Test helper functions
chan.uncorr_rayleigh_fading(float)
check_chan_gain(mod, chan)
assert_allclose(chan.k_factor, 0,
err_msg='Wrong k-factor with uncorrelated Rayleigh fading')
mean = randn(nb_rx, nb_tx)
chan.uncorr_rician_fading(mean, 10)
check_chan_gain(mod, chan)
assert_allclose(chan.k_factor, 10,
err_msg='Wrong k-factor with uncorrelated rician fading')
# Test on complex channel
for mod in self.all_mods:
# Test value checking after construction
with assert_raises(ValueError):
chan.fading_param = (ones((nb_tx, nb_tx)), ones((nb_tx, nb_tx)), ones((nb_rx, nb_rx)))
# Test with Rayleigh fading
chan.fading_param = (zeros((nb_rx, nb_tx), complex), identity(nb_tx), identity(nb_rx))
check_chan_gain(mod, chan)
assert_allclose(chan.channel_gains.mean(), 0, atol=1e-2,
err_msg='Wrong channel mean with complex channel')
assert_allclose(chan.channel_gains.var(), 1, atol=5e-2,
err_msg='Wrong channel variance with complex channel')
# Test with rician fading
mean = randn(nb_rx, nb_tx) + 1j * randn(nb_rx, nb_tx)
mean *= sqrt(prod_nb * 0.75 / einsum('ij,ij->', absolute(mean), absolute(mean)))
Rt = self.random_SDP_matrix(nb_tx) * sqrt(prod_nb) * 0.5
Rr = self.random_SDP_matrix(nb_rx) * sqrt(prod_nb) * 0.5
chan.fading_param = (mean, Rt, Rr)
check_chan_gain(mod, chan)
assert_allclose(chan.channel_gains.mean(0).real, mean.real, atol=0.1,
err_msg='Wrong channel mean with complex channel')
assert_allclose(chan.channel_gains.mean(0).imag, mean.imag, atol=0.1,
err_msg='Wrong channel mean with complex channel')
# Test helper functions
chan.uncorr_rayleigh_fading(complex)
check_chan_gain(mod, chan)
assert_allclose(chan.k_factor, 0,
err_msg='Wrong k-factor with uncorrelated Rayleigh fading')
mean = randn(nb_rx, nb_tx) + randn(nb_rx, nb_tx) * 1j
chan.uncorr_rician_fading(mean, 10)
check_chan_gain(mod, chan)
assert_allclose(chan.k_factor, 10,
err_msg='Wrong k-factor with uncorrelated rician fading')
chan.expo_corr_rayleigh_fading(exp(-0.2j * pi), exp(-0.1j * pi))
check_chan_gain(mod, chan)
assert_allclose(chan.k_factor, 0,
err_msg='Wrong k-factor with correlated Rayleigh fading')
Rt, Rr = expo_correlation(exp(-0.2j * pi), exp(-0.1j * pi))
check_correlation(chan, Rt, Rr)
mean = randn(nb_rx, nb_tx) + randn(nb_rx, nb_tx) * 1j
chan.expo_corr_rician_fading(mean, 10, exp(-0.1j * pi), exp(-0.2j * pi))
check_chan_gain(mod, chan)
assert_allclose(chan.k_factor, 10,
err_msg='Wrong k-factor with correlated rician fading')
# Test with beta > 0
chan.expo_corr_rayleigh_fading(exp(-0.2j * pi), exp(-0.1j * pi), 1, 0.5)
check_chan_gain(mod, chan)
assert_allclose(chan.k_factor, 0,
err_msg='Wrong k-factor with correlated Rayleigh fading')
mean = randn(nb_rx, nb_tx) + randn(nb_rx, nb_tx) * 1j
chan.expo_corr_rician_fading(mean, 5, exp(-0.1j * pi), exp(-0.2j * pi), 3, 2)
check_chan_gain(mod, chan)
assert_allclose(chan.k_factor, 5,
err_msg='Wrong k-factor with correlated rician fading')
def test_link_performance():
# Set seed
seed(8071996)
######################################
# Build models & desired solutions
######################################
models = []
desired_bers = []
snr_range = []
labels = []
rtols = []
code_rates = []
# SISO QPSK and AWGN channel
QPSK = QAMModem(4)
def receiver(y, h, constellation, noise_var):
return QPSK.demodulate(y, 'hard')
models.append(
LinkModel(QPSK.modulate, SISOFlatChannel(fading_param=(1 + 0j, 0)),
receiver, QPSK.num_bits_symbol, QPSK.constellation, QPSK.Es))
snr_range.append(arange(0, 9, 2))
desired_bers.append(erfc(sqrt(10**(snr_range[-1] / 10) / 2)) / 2)
labels.append('SISO QPSK and AWGN channel')
rtols.append(.25)
code_rates.append(1)
# MIMO 16QAM, 4x4 Rayleigh channel and hard-output K-Best
QAM16 = QAMModem(16)
RayleighChannel = MIMOFlatChannel(4, 4)
RayleighChannel.uncorr_rayleigh_fading(complex)
def receiver(y, h, constellation, noise_var):
return QAM16.demodulate(kbest(y, h, constellation, 16), 'hard')
models.append(
LinkModel(QAM16.modulate, RayleighChannel, receiver,
QAM16.num_bits_symbol, QAM16.constellation, QAM16.Es))
snr_range.append(arange(0, 21, 5) + 10 * log10(QAM16.num_bits_symbol))
desired_bers.append((2e-1, 1e-1, 3e-2, 2e-3, 4e-5)) # From reference
labels.append('MIMO 16QAM, 4x4 Rayleigh channel and hard-output K-Best')
rtols.append(1.25)
code_rates.append(1)
# MIMO 16QAM, 4x4 Rayleigh channel and soft-output best-first
QAM16 = QAMModem(16)
RayleighChannel = MIMOFlatChannel(4, 4)
RayleighChannel.uncorr_rayleigh_fading(complex)
ldpc_params = get_ldpc_code_params(
'commpy/channelcoding/designs/ldpc/wimax/1440.720.txt', True)
def modulate(bits):
return QAM16.modulate(
triang_ldpc_systematic_encode(bits, ldpc_params,
False).reshape(-1, order='F'))
def decoder(llrs):
return ldpc_bp_decode(llrs, ldpc_params, 'MSA',
15)[0][:720].reshape(-1, order='F')
def demode(symbs):
return QAM16.demodulate(symbs, 'hard')
def receiver(y, h, constellation, noise_var):
return best_first_detector(y, h, constellation, (1, 3, 5), noise_var,
demode, 500)
models.append(
LinkModel(modulate, RayleighChannel, receiver, QAM16.num_bits_symbol,
QAM16.constellation, QAM16.Es, decoder, 0.5))
snr_range.append(arange(17, 20, 1))
desired_bers.append((1.7e-1, 1e-1, 2.5e-3)) # From reference
labels.append(
'MIMO 16QAM, 4x4 Rayleigh channel and soft-output best-first')
rtols.append(2)
code_rates.append(.5)
######################################
# Make tests
######################################
for test in range(len(models)):
BERs = link_performance(models[test], snr_range[test], 5e5, 200, 720,
models[test].rate)
assert_allclose(BERs,
desired_bers[test],
rtol=rtols[test],
err_msg='Wrong performance for ' + labels[test])
full_metrics = models[test].link_performance_full_metrics(
snr_range[test], 2500, 200, 720, models[test].rate)
assert_allclose(full_metrics[0],
desired_bers[test],
rtol=rtols[test],
err_msg='Wrong performance for ' + labels[test])