LS channel estimation at UE based on CSI-RS

openair1/PHY/INIT/nr_init_ue.c

@@ -364,11 +364,16 @@ int init_nr_ue_signal(PHY_VARS_NR_UE *ue, int nb_connected_gNB)
         AssertFatal(ue->nr_csi_rs_info->nr_gold_csi_rs[slot][symb]!=NULL, "NR init: csi reference signal for slot %d symbol %d - malloc failed\n", slot, symb);
       }
     }
+    ue->nr_csi_rs_info->noise_power = (uint32_t*)malloc16_clear(sizeof(uint32_t));
     ue->nr_csi_rs_info->csi_rs_generated_signal = (int32_t **)malloc16(fp->nb_antennas_rx * sizeof(int32_t *) );
     ue->nr_csi_rs_info->csi_rs_received_signal = (int32_t **)malloc16(fp->nb_antennas_rx * sizeof(int32_t *) );
+    ue->nr_csi_rs_info->csi_rs_ls_estimated_channel = (int32_t **)malloc16(fp->nb_antennas_rx * sizeof(int32_t *) );
+    ue->nr_csi_rs_info->csi_rs_estimated_channel_freq = (int32_t **)malloc16(fp->nb_antennas_rx * sizeof(int32_t *) );
     for (i=0; i<fp->nb_antennas_rx; i++) {
       ue->nr_csi_rs_info->csi_rs_generated_signal[i] = (int32_t *) malloc16_clear(fp->samples_per_frame_wCP * sizeof(int32_t));
       ue->nr_csi_rs_info->csi_rs_received_signal[i] = (int32_t *) malloc16_clear(fp->samples_per_frame_wCP * sizeof(int32_t));
+      ue->nr_csi_rs_info->csi_rs_ls_estimated_channel[i] = (int32_t *) malloc16_clear(fp->samples_per_frame_wCP * sizeof(int32_t));
+      ue->nr_csi_rs_info->csi_rs_estimated_channel_freq[i] = (int32_t *) malloc16_clear(fp->samples_per_frame_wCP * sizeof(int32_t));
     }
 
     ue->nr_srs_info = (nr_srs_info_t *)malloc16_clear(sizeof(nr_srs_info_t));
@@ -647,6 +652,26 @@ void term_nr_ue_signal(PHY_VARS_NR_UE *ue, int nb_connected_gNB)
       free_and_zero(ue->pdcch_vars[th_id][gNB_id]);
     }
 
+    for (int i = 0; i < fp->nb_antennas_rx; i++) {
+      free_and_zero(ue->nr_csi_rs_info->csi_rs_generated_signal[i]);
+      free_and_zero(ue->nr_csi_rs_info->csi_rs_received_signal[i]);
+      free_and_zero(ue->nr_csi_rs_info->csi_rs_ls_estimated_channel[i]);
+      free_and_zero(ue->nr_csi_rs_info->csi_rs_estimated_channel_freq[i]);
+    }
+    for (int slot=0; slot<fp->slots_per_frame; slot++) {
+      for (int symb=0; symb<fp->symbols_per_slot; symb++) {
+        free_and_zero(ue->nr_csi_rs_info->nr_gold_csi_rs[slot][symb]);
+      }
+      free_and_zero(ue->nr_csi_rs_info->nr_gold_csi_rs[slot]);
+    }
+    free_and_zero(ue->nr_csi_rs_info->noise_power);
+    free_and_zero(ue->nr_csi_rs_info->nr_gold_csi_rs);
+    free_and_zero(ue->nr_csi_rs_info->csi_rs_generated_signal);
+    free_and_zero(ue->nr_csi_rs_info->csi_rs_received_signal);
+    free_and_zero(ue->nr_csi_rs_info->csi_rs_ls_estimated_channel);
+    free_and_zero(ue->nr_csi_rs_info->csi_rs_estimated_channel_freq);
+    free_and_zero(ue->nr_csi_rs_info);
+
     for (int i = 0; i < fp->nb_antennas_rx; i++) {
       free_and_zero(ue->nr_srs_info->srs_received_signal[i]);
       free_and_zero(ue->nr_srs_info->srs_ls_estimated_channel[i]);

openair1/PHY/NR_TRANSPORT/nr_csi_rs.c

@@ -79,6 +79,7 @@ void nr_generate_csi_rs(NR_DL_FRAME_PARMS frame_parms,
   uint8_t fi = 0;
   double rho, alpha;
   uint32_t beta = amp;
+  nr_csi_rs_info->csi_rs_generated_signal_bits = log2_approx(amp);
 
   AssertFatal(b!=0, "Invalid CSI frequency domain mapping: no bit selected in bitmap\n");
 
@@ -639,7 +640,7 @@ void nr_generate_csi_rs(NR_DL_FRAME_PARMS frame_parms,
               ((int16_t*)dataF[p])[((l*frame_parms.ofdm_symbol_size + k)<<1)+1+(2*dataF_offset)] = (beta*wt*wf*mod_csi[l][(mprime<<1) + 1]) >> 15;
             }
 #ifdef NR_CSIRS_DEBUG
-            printf("l,k (%d %d)  seq. index %d \t port %d \t (%d,%d)\n",l,k,mprime,p+3000,
+            printf("l,k (%d,%d)  seq. index %d \t port %d \t (%d,%d)\n",l,k,mprime,p+3000,
                    ((int16_t*)dataF[p])[((l*frame_parms.ofdm_symbol_size + k)<<1)+(2*dataF_offset)],
                    ((int16_t*)dataF[p])[((l*frame_parms.ofdm_symbol_size + k)<<1)+1+(2*dataF_offset)]);
 #endif

openair1/PHY/NR_UE_TRANSPORT/csi_rx.c

@@ -63,7 +63,7 @@ int nr_get_csi_rs_signal(PHY_VARS_NR_UE *ue,
 #ifdef NR_CSIRS_DEBUG
         int dataF_offset = proc->nr_slot_rx*ue->frame_parms.samples_per_slot_wCP;
         int16_t *tx_csi_rs_signal = (int16_t*)&nr_csi_rs_info->csi_rs_generated_signal[ant][symbol_offset+dataF_offset];
-        LOG_I(NR_PHY, "l,k (%d %d) \t tx (%d,%d) \t rx (%d,%d)\n",
+        LOG_I(NR_PHY, "l,k (%2d,%3d) |\ttx (%4d,%4d)\trx (%4d,%4d)\n",
               symb,
               nr_csi_rs_info->map_list[symb][k_id],
               tx_csi_rs_signal[k<<1],
@@ -78,6 +78,48 @@ int nr_get_csi_rs_signal(PHY_VARS_NR_UE *ue,
   return 0;
 }
 
+int nr_csi_rs_channel_estimation(PHY_VARS_NR_UE *ue,
+                                 UE_nr_rxtx_proc_t *proc,
+                                 nr_csi_rs_info_t *nr_csi_rs_info,
+                                 int32_t **csi_rs_generated_signal,
+                                 int32_t **csi_rs_received_signal,
+                                 int32_t **csi_rs_estimated_channel_freq,
+                                 uint32_t *noise_power) {
+
+  NR_DL_FRAME_PARMS *frame_parms = &ue->frame_parms;
+  int dataF_offset = proc->nr_slot_rx*ue->frame_parms.samples_per_slot_wCP;
+  int16_t ls_estimated[2];
+
+  for (int ant = 0; ant < frame_parms->nb_antennas_rx; ant++) {
+    for(int symb = 0; symb < NR_SYMBOLS_PER_SLOT; symb++) {
+
+      uint64_t symbol_offset = symb*frame_parms->ofdm_symbol_size;
+      int16_t *tx_csi_rs_signal = (int16_t*)&nr_csi_rs_info->csi_rs_generated_signal[ant][symbol_offset+dataF_offset];
+      int16_t *rx_csi_rs_signal = (int16_t*)&csi_rs_received_signal[ant][symbol_offset];
+
+      for(int k_id = 0; k_id<nr_csi_rs_info->k_list_length[symb]; k_id++) {
+        uint16_t k = nr_csi_rs_info->map_list[symb][k_id];
+        ls_estimated[0] = (int16_t)(((int32_t)tx_csi_rs_signal[k<<1]*rx_csi_rs_signal[k<<1] + (int32_t)tx_csi_rs_signal[(k<<1)+1]*rx_csi_rs_signal[(k<<1)+1])>>nr_csi_rs_info->csi_rs_generated_signal_bits);
+        ls_estimated[1] = (int16_t)(((int32_t)tx_csi_rs_signal[k<<1]*rx_csi_rs_signal[(k<<1)+1] - (int32_t)tx_csi_rs_signal[(k<<1)+1]*rx_csi_rs_signal[k<<1])>>nr_csi_rs_info->csi_rs_generated_signal_bits);
+
+#ifdef NR_CSIRS_DEBUG
+        LOG_I(NR_PHY, "l,k (%2d,%3d) |\ttx (%4d,%4d)\trx (%4d,%4d)\tls (%4d,%4d)\n",
+              symb,
+              nr_csi_rs_info->map_list[symb][k_id],
+              tx_csi_rs_signal[k<<1],
+              tx_csi_rs_signal[(k<<1)+1],
+              rx_csi_rs_signal[k<<1],
+              rx_csi_rs_signal[(k<<1)+1],
+              ls_estimated[0],
+              ls_estimated[1]);
+#endif
+      }
+    }
+  }
+
+  return 0;
+}
+
 int nr_ue_csi_im_procedures(PHY_VARS_NR_UE *ue, UE_nr_rxtx_proc_t *proc, uint8_t gNB_id) {
   return 0;
 }
@@ -117,5 +159,12 @@ int nr_ue_csi_rs_procedures(PHY_VARS_NR_UE *ue, UE_nr_rxtx_proc_t *proc, uint8_t
 
   nr_get_csi_rs_signal(ue, proc, ue->nr_csi_rs_info, ue->nr_csi_rs_info->csi_rs_received_signal);
 
+  nr_csi_rs_channel_estimation(ue,
+                               proc,
+                               ue->nr_csi_rs_info,
+                               ue->nr_csi_rs_info->csi_rs_generated_signal,
+                               ue->nr_csi_rs_info->csi_rs_received_signal,
+                               ue->nr_csi_rs_info->csi_rs_estimated_channel_freq,
+                               ue->nr_csi_rs_info->noise_power);
   return 0;
 }

openair1/PHY/defs_nr_common.h

@@ -268,8 +268,12 @@ typedef struct {
   uint32_t ***nr_gold_csi_rs;
   uint16_t k_list_length[NR_SYMBOLS_PER_SLOT];
   uint16_t map_list[NR_SYMBOLS_PER_SLOT][NR_MAX_CSI_RS_LENGTH];
+  uint8_t csi_rs_generated_signal_bits;
   int32_t **csi_rs_generated_signal;
   int32_t **csi_rs_received_signal;
+  int32_t **csi_rs_ls_estimated_channel;
+  int32_t **csi_rs_estimated_channel_freq;
+  uint32_t *noise_power;
 } nr_csi_rs_info_t;
 
 typedef struct NR_DL_FRAME_PARMS NR_DL_FRAME_PARMS;