gNB is receiving the SRS signal

cmake_targets/CMakeLists.txt

@@ -1756,6 +1756,7 @@ set(PHY_SRC_UE
 
   set(PHY_NR_SRC_COMMON
   ${OPENAIR1_DIR}/PHY/NR_TRANSPORT/nr_prach_common.c
+  ${OPENAIR1_DIR}/PHY/NR_UE_TRANSPORT/srs_modulation_nr.c
   )
 
   set(PHY_NR_SRC
@@ -1826,7 +1827,6 @@ set(PHY_SRC_UE
   ${OPENAIR1_DIR}/PHY/NR_TRANSPORT/nr_sch_dmrs.c
   ${OPENAIR1_DIR}/PHY/NR_UE_TRANSPORT/
   ${OPENAIR1_DIR}/PHY/NR_UE_TRANSPORT/nr_prach.c
-  ${OPENAIR1_DIR}/PHY/NR_UE_TRANSPORT/srs_modulation_nr.c
   ${OPENAIR1_DIR}/PHY/NR_UE_TRANSPORT/dci_nr.c
   ${OPENAIR1_DIR}/PHY/NR_UE_TRANSPORT/dci_tools_nr.c
   ${OPENAIR1_DIR}/PHY/NR_UE_TRANSPORT/pucch_nr.c

nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h

@@ -358,7 +358,6 @@ typedef struct {
   uint16_t t_srs;                     // SRS-Periodicity in slots [3GPP TS 38.211, Sec 6.4.1.4.4], Value: 1,2,3,4,5,8,10,16,20,32,40,64,80,160,320,640,1280,2560
   uint16_t t_offset;                  // Slot offset value [3GPP TS 38.211, Sec 6.4.1.4.3], Value:0->2559
   nfapi_nr_ue_ul_beamforming_t beamforming;
-  fapi_nr_ul_srs_parms_v4 srs_parms_v4;
 } fapi_nr_ul_config_srs_pdu;
 
 typedef struct {

openair1/PHY/INIT/nr_init.c

@@ -195,6 +195,12 @@ int phy_init_nr_gNB(PHY_VARS_gNB *gNB,
 
   nr_init_csi_rs(gNB, cfg->cell_config.phy_cell_id.value);
 
+  gNB->nr_srs_info = (nr_srs_info_t *)malloc16_clear(sizeof(nr_srs_info_t));
+  gNB->nr_srs_info->srs_generated_signal = (int32_t*)malloc16_clear(NR_NB_SC_PER_RB*NR_MAX_NB_RB*sizeof(int32_t));
+  gNB->nr_srs_info->srs_received_signal = (int32_t*)malloc16_clear(NR_NB_SC_PER_RB*NR_MAX_NB_RB*sizeof(int32_t));
+
+  generate_ul_reference_signal_sequences(SHRT_MAX);
+
   /* Generate low PAPR type 1 sequences for PUSCH DMRS, these are used if transform precoding is enabled.  */
   generate_lowpapr_typ1_refsig_sequences(SHRT_MAX);
 

openair1/PHY/INIT/nr_init_ue.c

@@ -323,6 +323,9 @@ int init_nr_ue_signal(PHY_VARS_NR_UE *ue,
     srs_vars[gNB_id] = (NR_UE_SRS *)malloc16_clear(sizeof(NR_UE_SRS));
 
     srs_vars[gNB_id]->active = false;
+    ue->nr_srs_info = (nr_srs_info_t *)malloc16_clear(sizeof(nr_srs_info_t));
+    ue->nr_srs_info->srs_generated_signal = (int32_t*)malloc16_clear(NR_NB_SC_PER_RB*NR_MAX_NB_RB*sizeof(int32_t));
+    ue->nr_srs_info->srs_received_signal = (int32_t*)malloc16_clear(NR_NB_SC_PER_RB*NR_MAX_NB_RB*sizeof(int32_t));
 
     if (abstraction_flag == 0) {
       for (th_id=0; th_id<RX_NB_TH_MAX; th_id++) {

openair1/PHY/NR_TRANSPORT/nr_transport_proto.h

@@ -317,7 +317,12 @@ void nr_fill_srs(PHY_VARS_gNB *gNB,
                  int slot,
                  nfapi_nr_srs_pdu_t *srs_pdu);
 
-void nr_get_srs_signal(PHY_VARS_gNB *gNB, int frame, int slot, nfapi_nr_srs_pdu_t *srs_pdu);
+int nr_get_srs_signal(PHY_VARS_gNB *gNB,
+                      int frame,
+                      int slot,
+                      nfapi_nr_srs_pdu_t *srs_pdu,
+                      nr_srs_info_t *nr_srs_info,
+                      int32_t *srs_received_signal);
 
 void init_prach_list(PHY_VARS_gNB *gNB);
 void init_prach_ru_list(RU_t *ru);

openair1/PHY/NR_TRANSPORT/srs_rx.c

@@ -25,7 +25,7 @@
  * \version 1.0
  */
 
-#include<stdio.h>
+#include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
@@ -40,6 +40,8 @@
 
 #include "T.h"
 
+//#define SRS_DEBUG
+
 NR_gNB_SRS_t *new_gNB_srs(void){
   NR_gNB_SRS_t *srs;
   srs = (NR_gNB_SRS_t *)malloc16(sizeof(NR_gNB_SRS_t));
@@ -86,6 +88,42 @@ void nr_fill_srs(PHY_VARS_gNB *gNB,
   memcpy((void*)&srs->srs_pdu, (void*)srs_pdu, sizeof(nfapi_nr_srs_pdu_t));
 }
 
-void nr_get_srs_signal(PHY_VARS_gNB *gNB, int frame, int slot, nfapi_nr_srs_pdu_t *srs_pdu) {
-  LOG_W(NR_PHY, "(%d.%d) nr_get_srs_signal is not implemented yet!\n", frame,slot);
+int nr_get_srs_signal(PHY_VARS_gNB *gNB,
+                       int frame,
+                       int slot,
+                       nfapi_nr_srs_pdu_t *srs_pdu,
+                       nr_srs_info_t *nr_srs_info,
+                       int32_t *srs_received_signal) {
+
+  if(nr_srs_info->n_symbs==0) {
+    LOG_E(NR_PHY, "nr_srs_info was not generated yet!\n");
+    return -1;
+  }
+
+  int32_t **rxdataF = gNB->common_vars.rxdataF;
+  NR_DL_FRAME_PARMS *frame_parms = &gNB->frame_parms;
+
+  uint16_t n_symbols = (slot&3)*frame_parms->symbols_per_slot;                    // number of symbols until this slot
+  uint8_t l0 = frame_parms->symbols_per_slot - 1 - srs_pdu->time_start_position;  // starting symbol in this slot
+  uint64_t symbol_offset = (n_symbols+l0)*frame_parms->ofdm_symbol_size;
+
+  int32_t *rx_signal;
+  for (int ant = 0; ant < frame_parms->nb_antennas_rx; ant++) {
+    rx_signal = &rxdataF[ant][symbol_offset + frame_parms->first_carrier_offset];
+
+    for(int sc_idx = 0; sc_idx < nr_srs_info->n_symbs; sc_idx++) {
+      srs_received_signal[nr_srs_info->subcarrier_idx[sc_idx] + frame_parms->first_carrier_offset] = rx_signal[nr_srs_info->subcarrier_idx[sc_idx]];
+
+#ifdef SRS_DEBUG
+    if(nr_srs_info->subcarrier_idx[sc_idx]%12 == 0) {
+      LOG_I(NR_PHY,"::::::::::::: %i :::::::::::::\n", nr_srs_info->subcarrier_idx[sc_idx]/12);
+    }
+    LOG_I(NR_PHY,"(%i)  \t%i\t%i\n",
+          nr_srs_info->subcarrier_idx[sc_idx],
+          srs_received_signal[nr_srs_info->subcarrier_idx[sc_idx] + frame_parms->first_carrier_offset]&0xFFFF,
+          (srs_received_signal[nr_srs_info->subcarrier_idx[sc_idx] + frame_parms->first_carrier_offset]>>16)&0xFFFF);
+#endif
+    }
+  }
+  return 0;
 }
\ No newline at end of file

openair1/PHY/NR_UE_TRANSPORT/srs_modulation_nr.c

@@ -74,11 +74,13 @@
 *                - no antenna switching*
 *
 *********************************************************************/
-int generate_srs_nr(fapi_nr_ul_config_srs_pdu *srs_config_pdu,
+int generate_srs_nr(nfapi_nr_srs_pdu_t *srs_config_pdu,
                     NR_DL_FRAME_PARMS *frame_parms,
                     int32_t *txptr,
+                    nr_srs_info_t *nr_srs_info,
                     int16_t amp,
-                        UE_nr_rxtx_proc_t *proc)
+                    int frame_number,
+                    int slot_number)
 {
   uint8_t n_SRS_cs_max;
   uint8_t u;
@@ -94,9 +96,6 @@ int generate_srs_nr(fapi_nr_ul_config_srs_pdu *srs_config_pdu,
   uint8_t N_b;
   uint8_t k_0_overbar_p;
 
-  int frame_number = proc->frame_tx;
-  int slot_number = proc->nr_slot_tx;
-
   // get parameters from srs_config_pdu
   uint8_t B_SRS  = srs_config_pdu->bandwidth_index;
   uint8_t C_SRS  = srs_config_pdu->config_index;
@@ -117,6 +116,10 @@ int generate_srs_nr(fapi_nr_ul_config_srs_pdu *srs_config_pdu,
   uint8_t l0 = N_SYMB_SLOT - 1 - l_offset;              // starting position in the time domain
   uint8_t k_0_p;                                        // frequency domain starting position
 
+  if(nr_srs_info) {
+    nr_srs_info->n_symbs = 0;
+  }
+
 #ifdef SRS_DEBUG
   LOG_I(NR_PHY,"Frame = %i, slot = %i\n", frame_number, slot_number);
   LOG_I(NR_PHY,"B_SRS = %i\n", B_SRS);
@@ -369,6 +372,11 @@ int generate_srs_nr(fapi_nr_ul_config_srs_pdu *srs_config_pdu,
 
       txptr[subcarrier+ofdm_symbol*frame_parms->ofdm_symbol_size] = (real_amp & 0xFFFF) + ((imag_amp<<16)&0xFFFF0000);
 
+      if(nr_srs_info) {
+        nr_srs_info->subcarrier_idx[nr_srs_info->n_symbs] = subcarrier+ofdm_symbol*frame_parms->ofdm_symbol_size-frame_parms->first_carrier_offset;
+        nr_srs_info->n_symbs++;
+      }
+
 #ifdef SRS_DEBUG
       if( (subcarrier+ofdm_symbol*frame_parms->ofdm_symbol_size-frame_parms->first_carrier_offset)%12 == 0 ) {
         LOG_I(NR_PHY,"------------ %i ------------\n",
@@ -417,7 +425,7 @@ int ue_srs_procedures_nr(PHY_VARS_NR_UE *ue, UE_nr_rxtx_proc_t *proc, uint8_t gN
   }
   ue->srs_vars[0]->active = false;
 
-  fapi_nr_ul_config_srs_pdu *srs_config_pdu = &ue->srs_vars[0]->srs_config_pdu;
+  nfapi_nr_srs_pdu_t *srs_config_pdu = (nfapi_nr_srs_pdu_t*)&ue->srs_vars[0]->srs_config_pdu;
 
 #ifdef SRS_DEBUG
   LOG_I(NR_PHY,"Frame = %i, slot = %i\n", proc->frame_tx, proc->nr_slot_tx);
@@ -452,7 +460,8 @@ int ue_srs_procedures_nr(PHY_VARS_NR_UE *ue, UE_nr_rxtx_proc_t *proc, uint8_t gN
   uint16_t nsymb = (ue->frame_parms.Ncp==0) ? 14:12;
   uint16_t symbol_offset = (int)ue->frame_parms.ofdm_symbol_size*((proc->nr_slot_tx*nsymb)+(nsymb-1));
 
-  if (generate_srs_nr(srs_config_pdu, frame_parms, &ue->common_vars.txdataF[gNB_id][symbol_offset], txptr, proc) == 0) {
+  if (generate_srs_nr(srs_config_pdu, frame_parms, &ue->common_vars.txdataF[gNB_id][symbol_offset], ue->nr_srs_info,
+                      txptr, proc->frame_tx, proc->nr_slot_tx) == 0) {
     return 0;
   } else {
     return -1;

openair1/PHY/NR_UE_TRANSPORT/srs_modulation_nr.h

@@ -136,15 +136,19 @@ EXTERN const uint16_t srs_periodicity[SRS_PERIODICITY]
 /** \brief This function generates the sounding reference symbol (SRS) for the uplink according to 38.211 6.4.1.4 Sounding reference signal
     @param frame_parms NR DL Frame parameters
     @param txdataF pointer to the frequency domain TX signal
+    @param nr_srs_info pointer to the srs info structure
     @param amp amplitude of generated signal
-    @param proc pointer to the transmit parameters
+    @param frame_number frame number
+    @param slot_number slot number
     @returns 0 on success -1 on error with message */
 
-int generate_srs_nr(fapi_nr_ul_config_srs_pdu *srs_config_pdu,
+int generate_srs_nr(nfapi_nr_srs_pdu_t *srs_config_pdu,
                     NR_DL_FRAME_PARMS *frame_parms,
                     int32_t *txptr,
+                    nr_srs_info_t *nr_srs_info,
                     int16_t amp,
-                    UE_nr_rxtx_proc_t *proc);
+                    int frame_number,
+                    int slot_number);
 
 /** \brief This function checks for periodic srs if srs should be transmitted in this slot
  *  @param p_SRS_Resource pointer to active resource

openair1/PHY/defs_gNB.h

@@ -794,6 +794,9 @@ typedef struct PHY_VARS_gNB_s {
   NR_gNB_UCI_STATS_t uci_stats[NUMBER_OF_NR_UCI_STATS_MAX];
   t_nrPolar_params    *uci_polarParams;
 
+  /// SRS variables
+  nr_srs_info_t *nr_srs_info;
+
   uint8_t pbch_configured;
   char gNB_generate_rar;
 

openair1/PHY/defs_nr_UE.h

@@ -973,6 +973,8 @@ typedef struct {
   /// PUSCH contention-based access vars
   PUSCH_CA_CONFIG_DEDICATED  pusch_ca_config_dedicated[NUMBER_OF_eNB_MAX]; // lola
 
+  /// SRS variables
+  nr_srs_info_t *nr_srs_info;
 
   //#if defined(UPGRADE_RAT_NR)
 #if 1

openair1/PHY/defs_nr_common.h

@@ -240,6 +240,13 @@ typedef struct {
   uint8_t init_msg1;
 } NR_PRACH_RESOURCES_t;
 
+typedef struct {
+  uint16_t n_symbs;
+  uint16_t subcarrier_idx[6*NR_MAX_NB_RB];
+  int32_t *srs_generated_signal;
+  int32_t *srs_received_signal;
+} nr_srs_info_t;
+
 typedef struct NR_DL_FRAME_PARMS NR_DL_FRAME_PARMS;
 
 typedef uint32_t (*get_samples_per_slot_t)(int slot, NR_DL_FRAME_PARMS* fp);

openair1/SCHED_NR/phy_procedures_nr_gNB.c

@@ -33,6 +33,7 @@
 #include "common/utils/LOG/vcd_signal_dumper.h"
 #include "PHY/INIT/phy_init.h"
 #include "PHY/MODULATION/nr_modulation.h"
+#include "PHY/NR_UE_TRANSPORT/srs_modulation_nr.h"
 #include "T.h"
 #include "executables/softmodem-common.h"
 
@@ -792,9 +793,17 @@ int phy_procedures_gNB_uespec_RX(PHY_VARS_gNB *gNB, int frame_rx, int slot_rx) {
     NR_gNB_SRS_t *srs = gNB->srs[i];
     if (srs) {
       if ((srs->active == 1) && (srs->frame == frame_rx) && (srs->slot == slot_rx)) {
+
         LOG_D(NR_PHY, "(%d.%d) gNB is waiting for SRS, id = %i\n", frame_rx, slot_rx, i);
+
         nfapi_nr_srs_pdu_t *srs_pdu = &srs->srs_pdu;
-        nr_get_srs_signal(gNB,frame_rx,slot_rx,srs_pdu);
+
+        // At least currently, the configuration is constant, so it is enough to generate the sequence just once.
+        if(gNB->nr_srs_info->n_symbs==0) {
+          generate_srs_nr(srs_pdu, &gNB->frame_parms, gNB->nr_srs_info->srs_generated_signal, gNB->nr_srs_info, AMP, frame_rx, slot_rx);
+        }
+
+        nr_get_srs_signal(gNB,frame_rx,slot_rx,srs_pdu, gNB->nr_srs_info, gNB->nr_srs_info->srs_received_signal);
         srs->active = 0;
       }
     }