csi: fix regression introduced in !3834

openair1/PHY/NR_UE_TRANSPORT/csi_rx.c

@@ -290,9 +290,10 @@ static int nr_csi_rs_channel_estimation(
 
           // loop over frequency resource elements within a group
           for (int kp = 0; kp <= csi_mapping->kprime; kp++) {
-
-            uint16_t kinit = (fp->first_carrier_offset + rb*NR_NB_SC_PER_RB) % fp->ofdm_symbol_size;
-            uint16_t k = kinit + csi_mapping->koverline[cdm_id] + kp;
+            uint16_t kinit_rx = (fp->first_carrier_offset + rb * NR_NB_SC_PER_RB) % fp->ofdm_symbol_size;
+            uint16_t k_rx = kinit_rx + csi_mapping->koverline[cdm_id] + kp;
+            uint16_t kinit_tx = rb * NR_NB_SC_PER_RB;
+            uint16_t k_tx = kinit_tx + csi_mapping->koverline[cdm_id] + kp;
 
             // loop over time resource elements within a group
             for (int lp = 0; lp <= csi_mapping->lprime; lp++) {
@@ -300,11 +301,12 @@ static int nr_csi_rs_channel_estimation(
               uint64_t symbol_offset = symb * fp->ofdm_symbol_size;
               const c16_t *tx_csi_rs_signal = &csi_rs_generated_signal[port_tx][symbol_offset];
               const c16_t *rx_csi_rs_signal = &csi_rs_received_signal[ant_rx][symbol_offset];
-              c16_t tmp = c16MulConjShift(tx_csi_rs_signal[k], rx_csi_rs_signal[k], nr_csi_info->csi_rs_generated_signal_bits);
+              c16_t tmp =
+                  c16MulConjShift(tx_csi_rs_signal[k_tx], rx_csi_rs_signal[k_rx], nr_csi_info->csi_rs_generated_signal_bits);
               // This is not just the LS estimation for each (k,l), but also the sum of the different contributions
               // for the sake of optimizing the memory used.
-              csi_rs_ls_estimated_channel[ant_rx][port_tx][kinit].r += tmp.r;
-              csi_rs_ls_estimated_channel[ant_rx][port_tx][kinit].i += tmp.i;
+              csi_rs_ls_estimated_channel[ant_rx][port_tx][kinit_rx].r += tmp.r;
+              csi_rs_ls_estimated_channel[ant_rx][port_tx][kinit_rx].i += tmp.i;
             }
           }
         }