Update tests & correct typos.

Author: BastienTr

commpy/channels.py

@@ -416,8 +416,8 @@ def uncorr_rayleigh_fading(self, dtype):
     def expo_corr_rayleigh_fading(self, t, r):
         """ Set the fading parameters to a complex correlated Rayleigh channel following the exponential model.
 
-        See: S. L. Loyka, « Channel capacity of MIMO architecture using the exponential correlation matrix », IEEE
-            Commun. Lett., vol. 5, nᵒ 9, p. 369‑371, sept. 2001.
+        See: S. L. Loyka, "Channel capacity if MIMO architecture using the exponential correlation matrix ", IEEE
+            Commun. Lett., vol.5, n. 9, p. 369-371, sept. 2001.
 
         Parameters
         ----------
@@ -470,8 +470,8 @@ def uncorr_rician_fading(self, mean, k_factor):
     def expo_corr_rician_fading(self, mean, k_factor, t, r):
         """ Set the fading parameters to a complex correlated rician channel following the exponential model.
 
-        See: S. L. Loyka, « Channel capacity of MIMO architecture using the exponential correlation matrix », IEEE
-            Commun. Lett., vol. 5, nᵒ 9, p. 369‑371, sept. 2001.
+        See: S. L. Loyka, "Channel capacity if MIMO architecture using the exponential correlation matrix ", IEEE
+            Commun. Lett., vol.5, n. 9, p. 369-371, sept. 2001.
 
         mean and correlation matricies will be scaled to fit the required k-factor.
 

commpy/links.py

@@ -15,6 +15,7 @@
 from __future__ import division  # Python 2 compatibility
 
 import numpy as np
+
 from commpy.channels import MIMOFlatChannel
 
 __all__ = ['link_performance', 'linkModel']
@@ -80,7 +81,7 @@ def link_performance(link_model, SNRs, send_max, err_min, send_chunk=None, code_
                      received_msg[receive_size * i:receive_size * (i+1)] = \
                          link_model.receive(channel_output[i], link_model.channel.channel_gains[i], link_model.constellation)
             else:
-                received_msg = channel_output
+                received_msg = link_model.receive(channel_output, link_model.channel.channel_gains, link_model.constellation)
             # Count errors
             bit_err += (msg != received_msg).sum()  # Remove MIMO padding
             bit_send += send_chunk

commpy/tests/test_channels.py

@@ -77,15 +77,15 @@ def check_chan_gain(mod, chan):
             # Test with Rayleigh fading
             chan.fading_param = (0, 1)
             check_chan_gain(mod, chan)
-            assert_allclose(absolute(chan.channel_gains.mean()), 0, atol=1e-2,
+            assert_allclose(absolute(chan.channel_gains.mean()), 0, atol=2e-2,
                             err_msg='Wrong channel mean with real channel')
             assert_allclose(chan.channel_gains.var(), 1, atol=0.2,
                             err_msg='Wrong channel variance with real channel')
 
             # Test with rician fading
             chan.fading_param = (sqrt(2 / 3), 1 / 3)
             check_chan_gain(mod, chan)
-            assert_allclose(chan.channel_gains.mean(), sqrt(2 / 3), atol=1e-2,
+            assert_allclose(chan.channel_gains.mean(), sqrt(2 / 3), atol=2e-2,
                             err_msg='Wrong channel mean with real channel')
             assert_allclose(chan.channel_gains.var(), 1 / 3, atol=0.2,
                             err_msg='Wrong channel variance with real channel')
@@ -105,15 +105,15 @@ def check_chan_gain(mod, chan):
             # Test with Rayleigh fading
             chan.fading_param = (0j, 1)
             check_chan_gain(mod, chan)
-            assert_allclose(absolute(chan.channel_gains.mean()), 0, atol=1e-2,
+            assert_allclose(absolute(chan.channel_gains.mean()), 0, atol=2e-2,
                             err_msg='Wrong channel mean with real channel')
             assert_allclose(chan.channel_gains.var(), 1, atol=0.2,
                             err_msg='Wrong channel variance with real channel')
 
             # Test with rician fading
             chan.fading_param = (0.5 + 0.5j, 0.5)
             check_chan_gain(mod, chan)
-            assert_allclose(absolute(chan.channel_gains.mean()), sqrt(0.5), atol=1e-2,
+            assert_allclose(absolute(chan.channel_gains.mean()), sqrt(0.5), atol=2e-2,
                             err_msg='Wrong channel mean with real channel')
             assert_allclose(chan.channel_gains.var(), 0.5, atol=0.2,
                             err_msg='Wrong channel variance with real channel')

commpy/tests/test_links.py

@@ -0,0 +1,50 @@
+# Authors: Bastien Trotobas <bastien.trotobas@gmail.com>
+# License: BSD 3-Clause
+
+from __future__ import division  # Python 2 compatibility
+
+from numpy import arange, sqrt, log10
+from numpy.random import seed
+from numpy.testing import run_module_suite, assert_allclose, dec
+from scipy.special import erfc
+
+from commpy.channels import MIMOFlatChannel, SISOFlatChannel
+from commpy.links import link_performance, linkModel
+from commpy.modulation import QAMModem, kbest
+
+
+@dec.slow
+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')
+
+
+if __name__ == "__main__":
+    seed(17121996)
+    run_module_suite()