PBCH generation/coding/Modulation

openair1/PHY/CODING/nrPolar_tools/nr_crc_byte.c

@@ -257,8 +257,8 @@ main()
 {
   unsigned char test[] = "Thebigredfox";
   crcTableInit();
-  printf("%x\n", crcbit(test, sizeof(test) - 1, poly24a));
-  printf("%x\n", crc24a(test, (sizeof(test) - 1)*8));
+  //printf("%x\n", crcbit(test, sizeof(test) - 1, poly24a));
+  //printf("%x\n", crc24a(test, (sizeof(test) - 1)*8));
   printf("%x\n", crcbit(test, sizeof(test) - 1, poly6));
   printf("%x\n", crc6(test, (sizeof(test) - 1)*8));
 }

openair1/PHY/CODING/nrPolar_tools/nr_polar_pbch_defs.h

@@ -5,7 +5,6 @@
 #ifndef __NR_POLAR_PBCH_DEFS__H__
 #define __NR_POLAR_PBCH_DEFS__H__
 
-
 #define NR_POLAR_PBCH_PAYLOAD_BITS 32 //uint16_t
 #define NR_POLAR_PBCH_CRC_PARITY_BITS 24
 #define NR_POLAR_PBCH_CRC_ERROR_CORRECTION_BITS 3

openair1/PHY/NR_REFSIG/nr_gold.c

@@ -38,7 +38,7 @@ void nr_init_pbch_dmrs(PHY_VARS_gNB* gNB)
   for (n_hf = 0; n_hf < N_hf; n_hf++) {
 
     for (l = 0; l < Lmax ; l++) {
-      i_ssb = l & Lmax;
+      i_ssb = l & (Lmax-1);
       i_ssb2 = (i_ssb<<2) + n_hf;
 
       x1 = 1 + (1<<31);

openair1/PHY/NR_TRANSPORT/nr_pbch.c

@@ -30,11 +30,13 @@
 * \warning
 */
 
+#include "PHY/defs_gNB.h"
 #include "PHY/NR_TRANSPORT/nr_transport.h"
 #include "PHY/phy_extern.h"
 #include "PHY/sse_intrin.h"
 
 //#define DEBUG_PBCH
+//#define DEBUG_PBCH_ENCODING
 
 extern short nr_mod_table[NR_MOD_TABLE_SIZE_SHORT];
 
@@ -42,7 +44,7 @@ int nr_generate_pbch_dmrs(uint32_t *gold_pbch_dmrs,
                           int32_t **txdataF,
                           int16_t amp,
                           uint8_t ssb_start_symbol,
-                          uint8_t nu,
+                          uint8_t nushift,
                           nfapi_config_request_t* config,
                           NR_DL_FRAME_PARMS *frame_parms)
 {
@@ -50,7 +52,7 @@ int nr_generate_pbch_dmrs(uint32_t *gold_pbch_dmrs,
   int16_t a;
   int16_t mod_dmrs[2 * NR_PBCH_DMRS_LENGTH];
 
-  LOG_I(PHY, "PBCH DMRS mapping started at symbol %d shift %d\n", ssb_start_symbol+1, nu);
+  LOG_I(PHY, "PBCH DMRS mapping started at symbol %d shift %d\n", ssb_start_symbol+1, nushift);
 
   /// BPSK modulation
   for (int m=0; m<NR_PBCH_DMRS_LENGTH; m++) {
@@ -67,9 +69,9 @@ int nr_generate_pbch_dmrs(uint32_t *gold_pbch_dmrs,
   for (int aa = 0; aa < config->rf_config.tx_antenna_ports.value; aa++)
   {
 
-    // PBCH DMRS are mapped  within the SSB block on every fourth subcarrier starting from nu of symbols 1, 2, 3
-      ///symbol 1  [0+nu:4:236+nu] -- 60 mod symbols
-    k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nu;
+    // PBCH DMRS are mapped  within the SSB block on every fourth subcarrier starting from nushift of symbols 1, 2, 3
+      ///symbol 1  [0+nushift:4:236+nushift] -- 60 mod symbols
+    k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift;
     l = ssb_start_symbol + 1;
 
     for (int m = 0; m < 60; m++) {
@@ -84,8 +86,8 @@ int nr_generate_pbch_dmrs(uint32_t *gold_pbch_dmrs,
         k-=frame_parms->ofdm_symbol_size;
     }
 
-      ///symbol 2  [0+u:4:44+nu ; 192+nu:4:236+nu] -- 24 mod symbols
-    k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nu;
+      ///symbol 2  [0+u:4:44+nushift ; 192+nu:4:236+nushift] -- 24 mod symbols
+    k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift;
     l++;
 
     for (int m = 60; m < 84; m++) {
@@ -100,8 +102,8 @@ int nr_generate_pbch_dmrs(uint32_t *gold_pbch_dmrs,
         k-=frame_parms->ofdm_symbol_size;
     }
 
-      ///symbol 3  [0+nu:4:236+nu] -- 60 mod symbols
-    k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nu;
+      ///symbol 3  [0+nushift:4:236+nushift] -- 60 mod symbols
+    k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift;
     l++;
 
     for (int m = 84; m < NR_PBCH_DMRS_LENGTH; m++) {
@@ -125,23 +127,141 @@ int nr_generate_pbch_dmrs(uint32_t *gold_pbch_dmrs,
   return 0;
 }
 
-#define NR_PBCH_LENGTH 1000
+void nr_pbch_scrambling(uint32_t Nid,
+                        uint8_t *pbch_a,
+                        uint32_t length)
+{
+  uint8_t reset;
+  uint32_t x1, x2, s=0;
+
+  reset = 1;
+  // x1 is set in lte_gold_generic
+  x2 = Nid;
+
+  for (int i=0; i<length; i++) {
+    if ((i&0x1f)==0) {
+      s = lte_gold_generic(&x1, &x2, reset);
+      reset = 0;
+    }
+    pbch_a[i] = (pbch_a[i]&1) ^ ((s>>(i&0x1f))&1);
+  }
+}
+
 
 int nr_generate_pbch(NR_gNB_PBCH *pbch,
                      uint8_t *pbch_pdu,
                      int32_t **txdataF,
                      int16_t amp,
                      uint8_t ssb_start_symbol,
-                     uint8_t nu,
+                     uint8_t nushift,
+                     uint8_t n_hf,
+                     int sfn,
+                     int frame_mod8,
                      nfapi_config_request_t* config,
                      NR_DL_FRAME_PARMS *frame_parms)
 {
 
   int m,k,l;
-  int a, aa;
-  int16_t mod_payload[2 * NR_PBCH_LENGTH];
+  int16_t a;
+  int16_t mod_pbch_e[NR_POLAR_PBCH_E<<1];
+  uint8_t sfn_4lsb, idx=0;
 
   LOG_I(PHY, "PBCH generation started\n");
 
+  ///Payload generation
+    // Fix byte endian
+  if (!frame_mod8)
+    for (int i=0; i<NR_PBCH_PDU_BITS; i++)
+      pbch->pbch_a[NR_PBCH_PDU_BITS-i-1] = pbch_pdu[i];
+
+    // Extra bits generation
+  sfn_4lsb = sfn&3;
+  for (int i=0; i<4; i++)
+    pbch->pbch_a[NR_PBCH_PDU_BITS+i] = (sfn_4lsb>>i)&1; // 4 lsb of sfn
+
+  pbch->pbch_a[NR_PBCH_PDU_BITS+4] = n_hf; // half frame index bit
+
+  pbch->pbch_a[NR_PBCH_PDU_BITS+5] = (config->sch_config.ssb_subcarrier_offset.value>>5)&1; //MSB of k0 -- Note the case Lssb=64 is not supported (FR2)
+
+    // Scrambling
+  nr_pbch_scrambling((uint32_t)config->sch_config.physical_cell_id.value, pbch->pbch_a, NR_POLAR_PBCH_PAYLOAD_BITS);
+
+  /// CRC, coding and rate matching
+  polar_encoder (pbch->pbch_a, pbch->pbch_e, &frame_parms->pbch_polar_params);
+
+  /// QPSK modulation
+  for (int i=0; i<NR_POLAR_PBCH_E>>2; i++){
+    idx = (pbch->pbch_e[i<<2]&1) ^ ((pbch->pbch_e[(i<<2)+1]&1)<<1);
+    mod_pbch_e[i<<2] = nr_mod_table[(NR_MOD_TABLE_QPSK_OFFSET + idx)<<1];
+    mod_pbch_e[(i<<2)+1] = nr_mod_table[((NR_MOD_TABLE_QPSK_OFFSET + idx)<<1)+1];
+
+#ifdef DEBUG_PBCH
+  printf("i %d  mod_pbch %d %d\n", i, mod_pbch_e[2*i], mod_pbch_e[2*i+1]);
+#endif
+  }
+
+  /// Resource mapping
+/*  a = (config->rf_config.tx_antenna_ports.value == 1) ? amp : (amp*ONE_OVER_SQRT2_Q15)>>15;
+
+  for (int aa = 0; aa < config->rf_config.tx_antenna_ports.value; aa++)
+  {
+
+    // PBCH DMRS are mapped  within the SSB block on every fourth subcarrier starting from nushift of symbols 1, 2, 3
+      ///symbol 1  [0+nushift:4:236+nushift] -- 60 mod symbols
+    k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift;
+    l = ssb_start_symbol + 1;
+
+    for (int m = 0; m < 60; m++) {
+#ifdef DEBUG_PBCH
+  printf("m %d at k %d of l %d\n", m, k, l);
+#endif
+      ((int16_t*)txdataF[aa])[(l*frame_parms->ofdm_symbol_size + k)<<1] = (a * mod_dmrs[m<<1]) >> 15;
+      ((int16_t*)txdataF[aa])[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (a * mod_dmrs[(m<<1) + 1]) >> 15;
+      k+=4;
+
+      if (k >= frame_parms->ofdm_symbol_size)
+        k-=frame_parms->ofdm_symbol_size;
+    }
+
+      ///symbol 2  [0+u:4:44+nushift ; 192+nu:4:236+nushift] -- 24 mod symbols
+    k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift;
+    l++;
+
+    for (int m = 60; m < 84; m++) {
+#ifdef DEBUG_PBCH
+  printf("m %d at k %d of l %d\n", m, k, l);
+#endif
+      ((int16_t*)txdataF[aa])[(l*frame_parms->ofdm_symbol_size + k)<<1] = (a * mod_dmrs[m<<1]) >> 15;
+      ((int16_t*)txdataF[aa])[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (a * mod_dmrs[(m<<1) + 1]) >> 15;
+      k+=(m==71)?148:4; // Jump from 44+nu to 192+nu
+
+      if (k >= frame_parms->ofdm_symbol_size)
+        k-=frame_parms->ofdm_symbol_size;
+    }
+
+      ///symbol 3  [0+nushift:4:236+nushift] -- 60 mod symbols
+    k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift;
+    l++;
+
+    for (int m = 84; m < NR_PBCH_DMRS_LENGTH; m++) {
+#ifdef DEBUG_PBCH
+  printf("m %d at k %d of l %d\n", m, k, l);
+#endif
+      ((int16_t*)txdataF[aa])[(l*frame_parms->ofdm_symbol_size + k)<<1] = (a * mod_dmrs[m<<1]) >> 15;
+      ((int16_t*)txdataF[aa])[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (a * mod_dmrs[(m<<1) + 1]) >> 15;
+      k+=4;
+
+      if (k >= frame_parms->ofdm_symbol_size)
+        k-=frame_parms->ofdm_symbol_size;
+    }
+
+  }
+
+
+#ifdef DEBUG_PBCH
+  write_output("txdataF.m", "txdataF", txdataF[0], frame_parms->samples_per_frame_wCP>>1, 1, 1);
+#endif
+
+*/
   return 0;
 }

openair1/PHY/NR_TRANSPORT/nr_transport.h

@@ -24,6 +24,7 @@
 
 #include "PHY/defs_gNB.h"
 
+#define NR_PBCH_PDU_BITS 24
 
 /*!
 \fn int nr_generate_pss
@@ -61,10 +62,19 @@ int nr_generate_pbch_dmrs(uint32_t *gold_pbch_dmrs,
                           int32_t **txdataF,
                           int16_t amp,
                           uint8_t ssb_start_symbol,
-                          uint8_t nu,
+                          uint8_t nushift,
                           nfapi_config_request_t* config,
                           NR_DL_FRAME_PARMS *frame_parms);
 
+/*!
+\fn int nr_pbch_scrambling
+\brief PBCH scrambling function
+@param
+ */
+void nr_pbch_scrambling(uint32_t Nid,
+                        uint8_t *pbch_a,
+                        uint32_t length);
+
 /*!
 \fn int nr_generate_pbch
 \brief Generation of the PBCH
@@ -76,7 +86,10 @@ int nr_generate_pbch(NR_gNB_PBCH *pbch,
                      int32_t **txdataF,
                      int16_t amp,
                      uint8_t ssb_start_symbol,
-                     uint8_t nu,
+                     uint8_t nushift,
+                     uint8_t n_hf,
+                     int sfn,
+                     int frame_mod8,
                      nfapi_config_request_t* config,
                      NR_DL_FRAME_PARMS *frame_parms);
 

openair1/PHY/defs_gNB.h

@@ -34,10 +34,12 @@
 
 #include "defs_eNB.h"
 #include "defs_nr_common.h"
+#include "CODING/nrPolar_tools/nr_polar_pbch_defs.h"
 
 
 typedef struct {
-  uint8_t pbch_d[100];
+  uint8_t pbch_a[NR_POLAR_PBCH_PAYLOAD_BITS];
+  uint8_t pbch_e[NR_POLAR_PBCH_E];
 } NR_gNB_PBCH;
 
 typedef struct {

openair1/SCHED_NR/phy_procedures_nr_gNB.c

@@ -122,24 +122,32 @@ void nr_common_signal_procedures (PHY_VARS_gNB *gNB,int frame, int subframe) {
   int **txdataF = gNB->common_vars.txdataF;
   uint8_t *pbch_pdu=&gNB->pbch_pdu[0];
   int ss_subframe = (cfg->sch_config.half_frame_index.value)? 5 : 0;
-  uint8_t Lmax, nu, ssb_index=0, n_hf=0;
+  int sfn = 10*frame + subframe;
+  int frame_mod8 = frame&7;
+  uint8_t Lmax, nushift, ssb_index=0, n_hf=0;
 
   LOG_D(PHY,"common_signal_procedures: frame %d, subframe %d\n",frame,subframe);
 
   int ssb_start_symbol = nr_get_ssb_start_symbol(cfg, fp);
   nr_set_ssb_first_subcarrier(cfg, fp);
   Lmax = (fp->dl_CarrierFreq < 3e9)? 4:8;
-  nu = (Lmax < 8)? ssb_index&3 : ssb_index&7;
+  nushift = (Lmax < 8)? ssb_index&3 : ssb_index&7;
 
 
   if (subframe == ss_subframe)
   {
     // Current implementation is based on SSB in first half frame, first candidate
     LOG_I(PHY,"SS TX: frame %d, subframe %d, start_symbol %d\n",frame,subframe, ssb_start_symbol);
+
     nr_generate_pss(gNB->d_pss, txdataF, AMP, ssb_start_symbol, cfg, fp);
     nr_generate_sss(gNB->d_sss, txdataF, AMP_OVER_2, ssb_start_symbol, cfg, fp);
-    nr_generate_pbch_dmrs(gNB->nr_gold_pbch_dmrs[n_hf][ssb_index],txdataF, AMP_OVER_2, ssb_start_symbol, nu, cfg, fp);
-    nr_generate_pbch(&gNB->pbch, pbch_pdu, txdataF, AMP_OVER_2, ssb_start_symbol, nu, cfg, fp);
+
+    /*if ((frame_mod8) == 0){
+      if (gNB->pbch_configured != 1)return;
+      gNB->pbch_configured = 0;
+    }*/
+    nr_generate_pbch_dmrs(gNB->nr_gold_pbch_dmrs[n_hf][ssb_index],txdataF, AMP_OVER_2, ssb_start_symbol, nushift, cfg, fp);
+    nr_generate_pbch(&gNB->pbch, pbch_pdu, txdataF, AMP_OVER_2, ssb_start_symbol, nushift, sfn, n_hf, frame_mod8, cfg, fp);
   }
 
 }