Implementation of function add_noise()

openair1/SIMULATION/NR_PHY/ulsim.c

@@ -305,7 +305,6 @@ int main(int argc, char **argv)
   int Imcs = 9;
   uint8_t precod_nbr_layers = 1;
   int gNB_id = 0;
-  int ap;
   int tx_offset;
   int32_t txlev_sum = 0, atxlev[4];
   int start_rb = 0;
@@ -1319,17 +1318,7 @@ int main(int argc, char **argv)
         } else {
           multipath_tv_channel(UE2gNB, s_re, s_im, r_re, r_im, 2*slot_length, 0);
         }
-
+        add_noise(rxdata, (const double **) r_re, (const double **) r_im, sigma, slot_length, slot_offset, ts, delay, pdu_bit_map, frame_parms->nb_antennas_rx);
-        for (i=0; i<slot_length; i++) {
-          for (ap=0; ap<frame_parms->nb_antennas_rx; ap++) {
-            rxdata[ap][slot_offset+i+delay].r = (int16_t)((r_re[ap][i]) + (sqrt(sigma/2)*gaussdouble(0.0,1.0))); // convert to fixed point
-            rxdata[ap][slot_offset+i+delay].i = (int16_t)((r_im[ap][i]) + (sqrt(sigma/2)*gaussdouble(0.0,1.0)));
-            /* Add phase noise if enabled */
-            if (pdu_bit_map & PUSCH_PDU_BITMAP_PUSCH_PTRS) {
-              phase_noise(ts, &rxdata[ap][slot_offset].r, &rxdata[ap][slot_offset].i);
-            }
-          }
-        }
 
       } /*End input_fd */
 

openair1/SIMULATION/TOOLS/multipath_channel.c

@@ -23,6 +23,7 @@
 #include <stdlib.h>
 #include <math.h>
 #include <string.h>
+#include "nfapi_nr_interface_scf.h"
 #include "PHY/TOOLS/tools_defs.h"
 #include "SIMULATION/RF/rf.h"
 #include "sim.h"
@@ -144,6 +145,31 @@ void multipath_channel(channel_desc_t *desc,
 }
 
 #else
+
+void add_noise(c16_t **rxdata,
+               const double **r_re,
+               const double **r_im,
+               const double sigma,
+               const int length,
+               const int slot_offset,
+               const double ts,
+               const int delay,
+               const uint16_t pdu_bit_map,
+               const uint8_t nb_antennas_rx)
+{
+  for (int i = 0; i < length; i++) {
+    for (int ap = 0; ap < nb_antennas_rx; ap++) {
+      c16_t *rxd = &rxdata[ap][slot_offset + i + delay];
+      rxd->r = r_re[ap][i] + sqrt(sigma / 2) * gaussdouble(0.0, 1.0); // convert to fixed point
+      rxd->i = r_im[ap][i] + sqrt(sigma / 2) * gaussdouble(0.0, 1.0);
+      /* Add phase noise if enabled */
+      if (pdu_bit_map & PUSCH_PDU_BITMAP_PUSCH_PTRS) {
+        phase_noise(ts, &rxdata[ap][slot_offset + i + delay].r, &rxdata[ap][slot_offset + i + delay].i);
+      }
+    }
+  }
+}
+
 void multipath_channel(channel_desc_t *desc,
                        double *tx_sig_re[NB_ANTENNAS_TX],
                        double *tx_sig_im[NB_ANTENNAS_TX],

openair1/SIMULATION/TOOLS/sim.h

@@ -348,6 +348,30 @@ void set_channeldesc_name(channel_desc_t *cdesc,char *modelname);
 */
 int random_channel(channel_desc_t *desc, uint8_t abstraction_flag);
 
+/**
+\brief Add AWGN noise and phase noise if enabled
+\param rxdata output data with noise
+\param r_re real part of input data without noise
+\param r_im imaginary part of input data without noise
+\param sigma noise power
+\param length number of samples to apply the noise
+\param slot_offset slot offset to start applying the noise
+\param ts sampling time
+\param delay introduce delay in terms of number of samples
+\param pdu_bit_map bitmap indicating presence of optional PDUs
+\param nb_antennas_rx number of receive antennas
+*/
+void add_noise(c16_t **rxdata,
+               const double **r_re,
+               const double **r_im,
+               const double sigma,
+               const int length,
+               const int slot_offset,
+               const double ts,
+               const int delay,
+               const uint16_t pdu_bit_map,
+               const uint8_t nb_antennas_rx);
+
 /**\fn void multipath_channel(channel_desc_t *desc,
            double tx_sig_re[NB_ANTENNAS_TX],
            double tx_sig_im[NB_ANTENANS_TX],