Fix cyclic prefix length of first symbol for 5g NR PUSCH

Signed-off-by: Daniel Schäufele <[email protected]>

Author: danielschaeufele

sionna/nr/carrier_config.py

@@ -6,6 +6,8 @@
 """
 # pylint: disable=line-too-long
 
+import numpy as np
+
 from .config import Config
 
 class CarrierConfig(Config):
@@ -244,16 +246,23 @@ def kappa(self):
     @property
     def cyclic_prefix_length(self):
         r"""
-        float, read-only : Cyclic prefix length
+        np.ndarray[float], read-only : Vector of cyclic prefix length of all
+            symbols in the current slot as defined in Section 5.3.1 [3GPP38211]_
             :math:`N_{\text{CP},l}^{\mu} \cdot T_{\text{c}}` [s]
         """
-        if self.cyclic_prefix=="extended":
-            cp =  512*self.kappa*2**(-self.mu)
+        cp = np.zeros(self.num_symbols_per_slot)
+        if self.cyclic_prefix == "extended":
+            cp[:] = 512 * self.kappa * 2 ** (-self.mu)
         else:
-            cp = 144*self.kappa*2**(-self.mu)
-            if self.slot_number in [0, 7*2**self.mu]:
-                cp += 16*self.kappa
-        return cp*self.t_c
+            cp[:] = 144 * self.kappa * 2 ** (-self.mu)
+
+            # Extend cyclic prefix for l=0 or l=7*2^\mu
+            long_cp_period = 7 * 2 ** self.mu
+            l_start = self.slot_number * self.num_symbols_per_slot
+            for i in range(l_start % long_cp_period,
+                           self.num_symbols_per_slot, long_cp_period):
+                cp[i] += 16 * self.kappa
+        return cp * self.t_c
 
     #-------------------#
     #---Class methods---#

sionna/nr/pusch_transmitter.py

@@ -168,7 +168,9 @@ def __init__(self,
                             subcarrier_spacing=self._subcarrier_spacing,
                             num_tx=self._num_tx,
                             num_streams_per_tx=self._num_layers,
-                            cyclic_prefix_length=self._cyclic_prefix_length,
+                            # TODO: pass vector of cyclic prefix lengths
+                            # (requires rewrite of channel simulation code)
+                            cyclic_prefix_length=self._cyclic_prefix_length[1],
                             pilot_pattern=self._pilot_pattern,
                             dtype=dtype)
 

test/unit/nr/test_pusch_config.py

@@ -8,7 +8,7 @@
 import numpy as np
 import tensorflow as tf
 import sionna
-from sionna.nr import PUSCHConfig
+from sionna.nr import PUSCHConfig, CarrierConfig
 from sionna import config
 
 script_dir = os.path.dirname(os.path.abspath(__file__))
@@ -228,3 +228,44 @@ def test_precoding_against_reference(self):
         for i in range(5):
             pusch_config.tpmi = i
             self.assertTrue(np.allclose(pusch_config.dmrs_grid_precoded/np.sqrt(3), ref[i]))
+
+
+class TestCarrierConfig(unittest.TestCase):
+    """Tests for the CarrierConfig Class"""
+
+    def test_cyclic_prefix_length(self):
+        carrier_config = CarrierConfig(subcarrier_spacing=15, slot_number=0)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, ([5.2] + [4.69]*6)*2, decimal=2)
+        carrier_config = CarrierConfig(subcarrier_spacing=15, slot_number=1)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, ([5.2] + [4.69]*6)*2, decimal=2)
+
+        carrier_config = CarrierConfig(subcarrier_spacing=30, slot_number=0)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [2.86] + [2.34]*13, decimal=2)
+        carrier_config = CarrierConfig(subcarrier_spacing=30, slot_number=1)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [2.86] + [2.34]*13, decimal=2)
+
+        carrier_config = CarrierConfig(subcarrier_spacing=60, slot_number=0)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [1.69] + [1.17]*13, decimal=2)
+        carrier_config = CarrierConfig(subcarrier_spacing=60, slot_number=1)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [1.17] * 14, decimal=2)
+
+        carrier_config = CarrierConfig(subcarrier_spacing=60, slot_number=0, cyclic_prefix='extended')
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [4.17] * 12, decimal=2)
+        carrier_config = CarrierConfig(subcarrier_spacing=60, slot_number=1, cyclic_prefix='extended')
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [4.17] * 12, decimal=2)
+
+        carrier_config = CarrierConfig(subcarrier_spacing=120, slot_number=0)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [1.11] + [0.59] * 13, decimal=2)
+        carrier_config = CarrierConfig(subcarrier_spacing=120, slot_number=1)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [0.59] * 14, decimal=2)
+        carrier_config = CarrierConfig(subcarrier_spacing=120, slot_number=2)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [0.59] * 14, decimal=2)
+        carrier_config = CarrierConfig(subcarrier_spacing=120, slot_number=3)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [0.59] * 14, decimal=2)
+        carrier_config = CarrierConfig(subcarrier_spacing=120, slot_number=4)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [1.11] + [0.59] * 13, decimal=2)
+
+        carrier_config = CarrierConfig(subcarrier_spacing=240, slot_number=0)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [0.81] + [0.29] * 13, decimal=2)
+        carrier_config = CarrierConfig(subcarrier_spacing=240, slot_number=1)
+        np.testing.assert_array_almost_equal(carrier_config.cyclic_prefix_length * 1e6, [0.29] * 14, decimal=2)