brute force multiple ssb detection works in pbchsim

openair1/PHY/NR_UE_ESTIMATION/nr_dl_channel_estimation.c

@@ -37,7 +37,9 @@ int nr_pbch_channel_estimation(PHY_VARS_NR_UE *ue,
 			       uint8_t eNB_offset,
 			       unsigned char Ns,
 			       unsigned char symbol,
-			       int dmrss)
+			       int dmrss,
+			       uint8_t ssb_index,
+			       uint8_t n_hf)
 {
   int pilot[200] __attribute__((aligned(16)));
   unsigned char aarx;
@@ -49,8 +51,6 @@ int nr_pbch_channel_estimation(PHY_VARS_NR_UE *ue,
   //uint16_t Nid_cell = (eNB_offset == 0) ? ue->frame_parms.Nid_cell : ue->measurements.adj_cell_id[eNB_offset-1];
 
   uint8_t nushift;
-  uint8_t ssb_index=ue->i_ssb;
-  uint8_t n_hf=ue->n_hf;  
   int **dl_ch_estimates  =ue->common_vars.common_vars_rx_data_per_thread[ue->current_thread_id[Ns>>1]].dl_ch_estimates[eNB_offset];
   int **rxdataF=ue->common_vars.common_vars_rx_data_per_thread[ue->current_thread_id[Ns>>1]].rxdataF;
 

openair1/PHY/NR_UE_ESTIMATION/nr_estimation.h

@@ -54,7 +54,9 @@ int nr_pbch_channel_estimation(PHY_VARS_NR_UE *ue,
                                uint8_t eNB_offset,
                                unsigned char Ns,
                                unsigned char symbol,
-			       int dmrss);
+			       int dmrss,
+			       uint8_t ssb_index,
+			       uint8_t n_hf);
 
 int nr_pdsch_channel_estimation(PHY_VARS_NR_UE *ue,
                               uint8_t eNB_offset,

openair1/PHY/NR_UE_TRANSPORT/nr_initial_sync.c

@@ -71,14 +71,12 @@ int nr_pbch_detection(PHY_VARS_NR_UE *ue, int pbch_initial_symbol, runmode_t mod
   for (int hf = 0; hf < N_hf; hf++) {
     for (int l = 0; l < N_L ; l++) {
       if (ret !=0) {
-        ue->i_ssb = l;
-        ue->n_hf = hf;
 
 #if UE_TIMING_TRACE
         start_meas(&ue->dlsch_channel_estimation_stats);
 #endif
         for(int i=pbch_initial_symbol; i<pbch_initial_symbol+3;i++)
-          nr_pbch_channel_estimation(ue,0,0,i,i-pbch_initial_symbol);
+          nr_pbch_channel_estimation(ue,0,0,i,i-pbch_initial_symbol,l,hf);
 #if UE_TIMING_TRACE
         stop_meas(&ue->dlsch_channel_estimation_stats);
 #endif
@@ -88,6 +86,7 @@ int nr_pbch_detection(PHY_VARS_NR_UE *ue, int pbch_initial_symbol, runmode_t mod
 		         ue->pbch_vars[0],
 		         frame_parms,
 		         0,
+			 l,
                          SISO,
 		         ue->high_speed_flag);
 
@@ -130,7 +129,7 @@ char prefix_string[2][9] = {"NORMAL","EXTENDED"};
 int nr_initial_sync(PHY_VARS_NR_UE *ue, runmode_t mode)
 {
 
-  int32_t sync_pos, sync_pos_slot; // k_ssb, N_ssb_crb, sync_pos2,
+  int32_t sync_pos, sync_pos_frame; // k_ssb, N_ssb_crb, sync_pos2,
   int32_t metric_tdd_ncp=0;
   uint8_t phase_tdd_ncp;
   double im, re;
@@ -173,20 +172,17 @@ int nr_initial_sync(PHY_VARS_NR_UE *ue, runmode_t mode)
   /* process pss search on received buffer */
   sync_pos = pss_synchro_nr(ue, NO_RATE_CHANGE);
 
-  sync_pos_slot = (fp->samples_per_subframe/fp->slots_per_subframe) - 10*(fp->ofdm_symbol_size + fp->nb_prefix_samples);
+  if (sync_pos >= fp->nb_prefix_samples)
+    ue->ssb_offset = sync_pos - fp->nb_prefix_samples;
+  else
+    ue->ssb_offset = sync_pos + (fp->samples_per_subframe * 10) - fp->nb_prefix_samples;
 
-  if (sync_pos >= fp->nb_prefix_samples){
-    ue->ssb_offset = sync_pos - fp->nb_prefix_samples;}
-  else{
-    ue->ssb_offset = sync_pos + (fp->samples_per_subframe * 10) - fp->nb_prefix_samples;}
-    
-  ue->rx_offset = ue->ssb_offset - sync_pos_slot;
 
   //write_output("rxdata1.m","rxd1",ue->common_vars.rxdata[0],10*fp->samples_per_subframe,1,1);
 
 #ifdef DEBUG_INITIAL_SYNCH
   LOG_I(PHY,"[UE%d] Initial sync : Estimated PSS position %d, Nid2 %d\n", ue->Mod_id, sync_pos,ue->common_vars.eNb_id);
-  LOG_I(PHY,"sync_pos %d ssb_offset %d sync_pos_slot %d \n",sync_pos,ue->ssb_offset,sync_pos_slot);
+  LOG_I(PHY,"sync_pos %d ssb_offset %d \n",sync_pos,ue->ssb_offset);
 #endif
 
   // digital compensation of FFO for SSB symbols
@@ -240,6 +236,13 @@ int nr_initial_sync(PHY_VARS_NR_UE *ue, runmode_t mode)
     nr_gold_pbch(ue);
     ret = nr_pbch_detection(ue,1,mode);  // start pbch detection at first symbol after pss
 
+    if (ret == 0) {
+      // sync at symbol ue->symbol_offset
+      // computing the offset wrt the beginning of the frame
+      sync_pos_frame = (fp->ofdm_symbol_size + fp->nb_prefix_samples0)+((ue->symbol_offset)-1)*(fp->ofdm_symbol_size + fp->nb_prefix_samples);
+      ue->rx_offset = ue->ssb_offset - sync_pos_frame;
+    }   
+
     nr_gold_pdcch(ue,0, 2);
     /*
     int nb_prefix_samples0 = fp->nb_prefix_samples0;
@@ -263,7 +266,7 @@ int nr_initial_sync(PHY_VARS_NR_UE *ue, runmode_t mode)
   }
   else {
 #ifdef DEBUG_INITIAL_SYNCH
-    LOG_I(PHY,"TDD Normal prefix: SSS error condition: sync_pos %d, sync_pos_slot %d\n", sync_pos, sync_pos_slot);
+    LOG_I(PHY,"TDD Normal prefix: SSS error condition: sync_pos %d\n", sync_pos);
 #endif
   }
   }

openair1/PHY/NR_UE_TRANSPORT/nr_pbch.c

@@ -414,6 +414,7 @@ int nr_rx_pbch( PHY_VARS_NR_UE *ue,
                 NR_UE_PBCH *nr_ue_pbch_vars,
                 NR_DL_FRAME_PARMS *frame_parms,
                 uint8_t eNB_id,
+                uint8_t i_ssb,
                 MIMO_mode_t mimo_mode,
                 uint32_t high_speed_flag) {
   NR_UE_COMMON *nr_ue_common_vars = &ue->common_vars;
@@ -424,10 +425,9 @@ int nr_rx_pbch( PHY_VARS_NR_UE *ue,
   //uint32_t pbch_a_prime;
   int16_t *pbch_e_rx;
   uint8_t *decoded_output = nr_ue_pbch_vars->decoded_output;
-  uint8_t nushift;
+  uint8_t nushift,n_hf,ssb_index;
   uint16_t M;
   uint8_t Lmax=frame_parms->Lmax; 
-  uint8_t ssb_index=ue->i_ssb;
   //uint16_t crc;
   //unsigned short idx_demod =0;
   uint32_t decoderState=0;
@@ -443,7 +443,7 @@ int nr_rx_pbch( PHY_VARS_NR_UE *ue,
   int symbol_offset=1;
 
   if (ue->is_synchronized > 0)
-    symbol_offset=2;
+    symbol_offset=ue->symbol_offset;
   else
     symbol_offset=0;
 
@@ -527,7 +527,7 @@ int nr_rx_pbch( PHY_VARS_NR_UE *ue,
 #endif
   //un-scrambling
   M =  NR_POLAR_PBCH_E;
-  nushift = (Lmax==4)? ssb_index&3 : ssb_index&7;
+  nushift = (Lmax==4)? i_ssb&3 : i_ssb&7;
   uint32_t unscrambling_mask = (Lmax==64)?0x100006D:0x1000041;
   nr_pbch_unscrambling(nr_ue_pbch_vars,frame_parms->Nid_cell,nushift,M,NR_POLAR_PBCH_E,0,0);
   //polar decoding de-rate matching
@@ -571,6 +571,16 @@ int nr_rx_pbch( PHY_VARS_NR_UE *ue,
   for (int i=0; i<3; i++)
     decoded_output[i] = (uint8_t)((payload>>((3-i)<<3))&0xff);
 
+  n_hf = ((xtra_byte>>4)&0x01); // computing the half frame index from the extra byte
+
+  ssb_index = i_ssb;  // ssb index corresponds to i_ssb for Lmax = 4,8
+  if (Lmax == 64) {   // for Lmax = 64 ssb index 4th,5th and 6th bits are in extra byte
+    for (int i=0; i<3; i++)
+      ssb_index += (((xtra_byte>>(7-i))&0x01)<<(3+i));
+  }
+
+  ue->symbol_offset = nr_get_ssb_start_symbol(frame_parms, ssb_index, n_hf);
+
 #ifdef DEBUG_PBCH
   printf("xtra_byte %x payload %x\n", xtra_byte, payload);
 
@@ -578,14 +588,14 @@ int nr_rx_pbch( PHY_VARS_NR_UE *ue,
     //     printf("unscrambling pbch_a[%d] = %x \n", i,pbch_a[i]);
     printf("[PBCH] decoder payload[%d] = %x\n",i,decoded_output[i]);
   }
-
 #endif
+
   ue->dl_indication.rx_ind = &ue->rx_ind; //  hang on rx_ind instance
   //ue->rx_ind.sfn_slot = 0;  //should be set by higher-1-layer, i.e. clean_and_set_if_instance()
   ue->rx_ind.rx_indication_body[0].pdu_type = FAPI_NR_RX_PDU_TYPE_MIB;
   ue->rx_ind.rx_indication_body[0].mib_pdu.pdu = &decoded_output[0];
   ue->rx_ind.rx_indication_body[0].mib_pdu.additional_bits = xtra_byte;
-  ue->rx_ind.rx_indication_body[0].mib_pdu.ssb_index = ssb_index;            //  confirm with TCL
+  ue->rx_ind.rx_indication_body[0].mib_pdu.ssb_index = i_ssb;                //  confirm with TCL
   ue->rx_ind.rx_indication_body[0].mib_pdu.ssb_length = Lmax;                //  confirm with TCL
   ue->rx_ind.rx_indication_body[0].mib_pdu.cell_id = frame_parms->Nid_cell;  //  confirm with TCL
   ue->rx_ind.number_pdus = 1;

openair1/PHY/NR_UE_TRANSPORT/nr_transport_proto_ue.h

@@ -1122,6 +1122,7 @@ int nr_rx_pbch( PHY_VARS_NR_UE *ue,
 		     NR_UE_PBCH *nr_ue_pbch_vars,
 		     NR_DL_FRAME_PARMS *frame_parms,
 		     uint8_t eNB_id,
+                     uint8_t i_ssb,
 		     MIMO_mode_t mimo_mode,
 		     uint32_t high_speed_flag);
 

openair1/PHY/defs_nr_UE.h

@@ -1143,8 +1143,7 @@ typedef struct {
   uint8_t               decode_MIB;
   /// temporary offset during cell search prior to MIB decoding
   int              ssb_offset;
-  uint8_t          i_ssb;
-  uint8_t          n_hf;
+  uint16_t	   symbol_offset; // offset in terms of symbols for detected ssb in sync
   int              rx_offset; /// Timing offset
   int              rx_offset_diff; /// Timing adjustment for ofdm symbol0 on HW USRP
   int              time_sync_cell;

openair1/SCHED_NR_UE/phy_procedures_nr_ue.c

@@ -2973,6 +2973,7 @@ void nr_ue_pbch_procedures(uint8_t eNB_id,PHY_VARS_NR_UE *ue,UE_nr_rxtx_proc_t *
 		   ue->pbch_vars[eNB_id],
 		   &ue->frame_parms,
 		   eNB_id,
+		   ue->rx_ind.rx_indication_body[0].mib_pdu.ssb_index,
 		   SISO,
 		   ue->high_speed_flag);
 
@@ -5098,9 +5099,13 @@ int phy_procedures_nrUE_RX(PHY_VARS_NR_UE *ue,UE_nr_rxtx_proc_t *proc,uint8_t eN
   if ( (nr_tti_rx == 0) && (ue->decode_MIB == 1))
     {
       LOG_D(PHY," ------  PBCH ChannelComp/LLR: frame.slot %d.%d ------  \n", frame_rx%1024, nr_tti_rx);
-      for (int i=0; i<3; i++) {
+
+      uint8_t i_ssb = ue->rx_ind.rx_indication_body[0].mib_pdu.ssb_index;
+      uint8_t n_hf = (((ue->rx_ind.rx_indication_body[0].mib_pdu.additional_bits)>>4)&0x01);
+
+      for (int i=1; i<4; i++) {
 	nr_slot_fep(ue,
-		    (5+i), //mu=1 case B
+		    (ue->symbol_offset+i), //mu=1 case B
 		    nr_tti_rx,
 		    0,
 		    0,
@@ -5109,7 +5114,7 @@ int phy_procedures_nrUE_RX(PHY_VARS_NR_UE *ue,UE_nr_rxtx_proc_t *proc,uint8_t eN
 #if UE_TIMING_TRACE
   	start_meas(&ue->dlsch_channel_estimation_stats);
 #endif
-   	nr_pbch_channel_estimation(ue,0,0,5+i,i);
+   	nr_pbch_channel_estimation(ue,0,0,ue->symbol_offset+i,i-1,i_ssb,n_hf);
 #if UE_TIMING_TRACE
   	stop_meas(&ue->dlsch_channel_estimation_stats);
 #endif

openair1/SIMULATION/NR_PHY/pbchsim.c

@@ -129,7 +129,7 @@ int main(int argc, char **argv)
   unsigned char frame_type = 0;
   unsigned char pbch_phase = 0;
 
-  int frame=0,subframe=0;
+  int frame=0;
   int frame_length_complex_samples;
   int frame_length_complex_samples_no_prefix;
   NR_DL_FRAME_PARMS *frame_parms;
@@ -610,8 +610,8 @@ int main(int argc, char **argv)
 	uint8_t ssb_index = 0;
         while (!((SSB_positions >> ssb_index) & 0x01)) ssb_index++;  // to select the first transmitted ssb
 
-	int start_symbol = nr_get_ssb_start_symbol(frame_parms, ssb_index, n_hf);
-	for (int i=start_symbol+1; i<start_symbol+4; i++) {
+	UE->symbol_offset = nr_get_ssb_start_symbol(frame_parms, ssb_index, n_hf);
+	for (int i=UE->symbol_offset+1; i<UE->symbol_offset+4; i++) {
 	  nr_slot_fep(UE,
 	  	      i,
 		      0,
@@ -620,7 +620,7 @@ int main(int argc, char **argv)
 		      NR_PBCH_EST);
         }
 
-	ret = nr_pbch_detection(UE,start_symbol+1,0);
+	ret = nr_pbch_detection(UE,UE->symbol_offset+1,0);
 
 	if (ret==0) {
 	  //UE->rx_ind.rx_indication_body->mib_pdu.ssb_index;  //not yet detected automatically