phy: remove function pointers in frame param

1. Removed function pointers for functions get_samples_per_slot(),
   get_samples_slot_timestamp() and get_slot_from_timestamp() as it does
   not offer any advantage. The functions are now called directly from
   everywhere.
2. Optimized these functions by removing loops where ever possible.

openair1/PHY/INIT/nr_parms.c

@@ -310,31 +310,65 @@ uint32_t get_samples_symbol_timestamp(const NR_DL_FRAME_PARMS *fp, int slot, int
 
 uint32_t get_slot_from_timestamp(openair0_timestamp timestamp_rx, const NR_DL_FRAME_PARMS *fp)
 {
-   uint32_t slot_idx = 0;
-   int samples_till_the_slot = fp->get_samples_per_slot(slot_idx,fp)-1;
-   timestamp_rx = timestamp_rx%fp->samples_per_frame;
+  timestamp_rx = timestamp_rx % fp->samples_per_frame;
+  if (timestamp_rx < fp->samples_per_slot0)
+    return 0;
 
-    while (timestamp_rx > samples_till_the_slot) {
-        slot_idx++;
-        samples_till_the_slot += fp->get_samples_per_slot(slot_idx,fp);
-     }
-   return slot_idx; 
+  if (fp->numerology_index == 0)
+    return timestamp_rx / fp->samples_per_subframe;
+
+  const unsigned int num_half_sf = timestamp_rx / (fp->samples_per_subframe / 2);
+  const unsigned int slot_per_half_sf = fp->slots_per_subframe / 2;
+
+  uint32_t slot_count = num_half_sf * slot_per_half_sf;
+  int samp_idx = num_half_sf * (fp->samples_per_subframe / 2) - 1;
+
+  // Remaining samples
+  if (samp_idx < timestamp_rx) {
+    slot_count++;
+    samp_idx += fp->samples_per_slot0; // First slot of half subframe
+  }
+  if (samp_idx < timestamp_rx) {
+    const unsigned int rem_samples = timestamp_rx - samp_idx;
+    const unsigned int num_slots = ceil((double)rem_samples / fp->samples_per_slotN0);
+    slot_count += num_slots;
+  }
+
+  return slot_count - 1;
 }
 
-uint32_t get_samples_slot_timestamp(int slot, const NR_DL_FRAME_PARMS *fp, unsigned int sl_ahead)
+uint32_t get_samples_slot_timestamp(const NR_DL_FRAME_PARMS *fp, unsigned int slot)
 {
-  uint32_t samp_count = 0;
+  if (slot == 0)
+    return 0;
 
-  if(!sl_ahead) {
-    for(unsigned int idx_slot = 0; idx_slot < slot; idx_slot++)
-      samp_count += fp->get_samples_per_slot(idx_slot, fp);
-  } else {
-    for (unsigned int idx_slot = slot; idx_slot < slot + sl_ahead; idx_slot++)
-      samp_count += fp->get_samples_per_slot(idx_slot, fp);
+  if (fp->numerology_index == 0)
+    return slot * fp->samples_per_subframe;
+
+  uint32_t samp_count = 0;
+  // Number of half subframes
+  const unsigned int num_half_sf = slot / (fp->slots_per_subframe / 2);
+  samp_count += num_half_sf * fp->samples_per_subframe / 2;
+
+  // Remaining slots
+  unsigned int rem_slots = slot % (fp->slots_per_subframe / 2);
+  if (rem_slots > 0) {
+    samp_count += fp->samples_per_slot0; // First slot of the last half subframe
+    rem_slots--;
   }
+  samp_count += rem_slots * fp->samples_per_slotN0; // Remaining slots of the last half subframe
+
   return samp_count;
 }
 
+uint32_t get_samples_slot_duration(const NR_DL_FRAME_PARMS *fp, unsigned int start_slot, unsigned int num_slots)
+{
+  if (start_slot == 0 && num_slots == 0)
+    return 0;
+
+  return (get_samples_slot_timestamp(fp, start_slot + num_slots) - get_samples_slot_timestamp(fp, start_slot));
+}
+
 void nr_init_frame_parms(nfapi_nr_config_request_scf_t* cfg, NR_DL_FRAME_PARMS *fp)
 {
 
@@ -371,9 +405,6 @@ void nr_init_frame_parms(nfapi_nr_config_request_scf_t* cfg, NR_DL_FRAME_PARMS *
   fp->samples_per_slot0 = fp->nb_prefix_samples0 + ((fp->symbols_per_slot-1)*fp->nb_prefix_samples) + (fp->symbols_per_slot*fp->ofdm_symbol_size); 
   fp->samples_per_subframe = (fp->nb_prefix_samples0 + fp->ofdm_symbol_size) * 2 + 
                              (fp->nb_prefix_samples + fp->ofdm_symbol_size) * (fp->symbols_per_slot * fp->slots_per_subframe - 2); 
-  fp->get_samples_per_slot = &get_samples_per_slot;
-  fp->get_samples_slot_timestamp = &get_samples_slot_timestamp;
-  fp->get_slot_from_timestamp = &get_slot_from_timestamp;
   fp->samples_per_frame = 10 * fp->samples_per_subframe;
   fp->freq_range = get_freq_range_from_freq(fp->dl_CarrierFreq);
 
@@ -454,8 +485,6 @@ int nr_init_frame_parms_ue(NR_DL_FRAME_PARMS *fp,
   fp->samples_per_slot0 = fp->nb_prefix_samples0 + ((fp->symbols_per_slot-1)*fp->nb_prefix_samples) + (fp->symbols_per_slot*fp->ofdm_symbol_size); 
   fp->samples_per_subframe = (fp->nb_prefix_samples0 + fp->ofdm_symbol_size) * 2 + 
                              (fp->nb_prefix_samples + fp->ofdm_symbol_size) * (fp->symbols_per_slot * fp->slots_per_subframe - 2); 
-  fp->get_samples_per_slot = &get_samples_per_slot;
-  fp->get_samples_slot_timestamp = &get_samples_slot_timestamp;
   fp->samples_per_frame = 10 * fp->samples_per_subframe;
   fp->freq_range = get_freq_range_from_freq(fp->dl_CarrierFreq);
 
@@ -512,8 +541,6 @@ void nr_init_frame_parms_ue_sa(NR_DL_FRAME_PARMS *frame_parms, uint64_t downlink
   frame_parms->samples_per_slot0 = frame_parms->nb_prefix_samples0 + ((frame_parms->symbols_per_slot-1)*frame_parms->nb_prefix_samples) + (frame_parms->symbols_per_slot*frame_parms->ofdm_symbol_size);
   frame_parms->samples_per_subframe = (frame_parms->nb_prefix_samples0 + frame_parms->ofdm_symbol_size) * 2 +
                              (frame_parms->nb_prefix_samples + frame_parms->ofdm_symbol_size) * (frame_parms->symbols_per_slot * frame_parms->slots_per_subframe - 2);
-  frame_parms->get_samples_per_slot = &get_samples_per_slot;
-  frame_parms->get_samples_slot_timestamp = &get_samples_slot_timestamp;
   frame_parms->samples_per_frame = 10 * frame_parms->samples_per_subframe;
 
   LOG_W(PHY, "samples_per_subframe %d/per second %d, wCP %d\n", frame_parms->samples_per_subframe, 1000*frame_parms->samples_per_subframe, frame_parms->samples_per_subframe_wCP);
@@ -613,8 +640,6 @@ int nr_init_frame_parms_ue_sl(NR_DL_FRAME_PARMS *fp,
       fp->nb_prefix_samples0 + ((fp->symbols_per_slot - 1) * fp->nb_prefix_samples) + (fp->symbols_per_slot * fp->ofdm_symbol_size);
   fp->samples_per_subframe = (fp->nb_prefix_samples0 + fp->ofdm_symbol_size) * 2
                              + (fp->nb_prefix_samples + fp->ofdm_symbol_size) * (fp->symbols_per_slot * fp->slots_per_subframe - 2);
-  fp->get_samples_per_slot = &get_samples_per_slot;
-  fp->get_samples_slot_timestamp = &get_samples_slot_timestamp;
   fp->samples_per_frame = 10 * fp->samples_per_subframe;
   fp->freq_range = get_freq_range_from_freq(fp->sl_CarrierFreq);
 

openair1/PHY/INIT/tests/test_nr_frame_params.cpp

@@ -33,11 +33,11 @@ softmodem_params_t *get_softmodem_params(void)
 
 void test_coherence_symbol_api(NR_DL_FRAME_PARMS *fp)
 {
-  EXPECT_EQ(get_samples_symbol_timestamp(fp, 0, 0), fp->get_samples_slot_timestamp(0, fp, 0));
+  EXPECT_EQ(get_samples_symbol_timestamp(fp, 0, 0), get_samples_slot_timestamp(fp, 0));
 
   for (int slot = 0; slot < 4; slot++) {
-    EXPECT_EQ(get_samples_symbol_duration(fp, slot, 0, fp->symbols_per_slot) + fp->get_samples_slot_timestamp(slot, fp, 0),
-              fp->get_samples_slot_timestamp(slot + 1, fp, 0));
+    EXPECT_EQ(get_samples_symbol_duration(fp, slot, 0, fp->symbols_per_slot) + get_samples_slot_timestamp(fp, slot),
+              get_samples_slot_timestamp(fp, slot + 1));
   }
 
   for (int symbol = 0; symbol < fp->symbols_per_slot - 1; symbol++) {

openair1/PHY/MODULATION/slot_fep_nr.c

@@ -80,7 +80,7 @@ int nr_slot_fep(PHY_VARS_NR_UE *ue,
   // For Sidelink 16 frames worth of samples is processed to find SSB, for 5G-NR 2.
   const unsigned int total_samples = (is_sl) ? 16 * frame_parms->samples_per_frame : 2 * frame_parms->samples_per_frame;
 
-  unsigned int rx_offset = frame_parms->get_samples_slot_timestamp(slot, frame_parms, 0);
+  unsigned int rx_offset = get_samples_slot_timestamp(frame_parms, slot);
   const unsigned int abs_symbol = slot * frame_parms->symbols_per_slot + symbol;
   for (int idx_symb = slot * frame_parms->symbols_per_slot; idx_symb <= abs_symbol; idx_symb++)
     rx_offset += (idx_symb % (0x7 << frame_parms->numerology_index)) ? nb_prefix_samples : nb_prefix_samples0;
@@ -150,7 +150,7 @@ int nr_slot_fep_ul(NR_DL_FRAME_PARMS *frame_parms,
   int32_t tmp_dft_in[8192] __attribute__ ((aligned (32)));
 
   // offset of first OFDM symbol
-  unsigned int rxdata_offset = frame_parms->get_samples_slot_timestamp(Ns,frame_parms,0);
+  unsigned int rxdata_offset = get_samples_slot_timestamp(frame_parms, Ns);
   unsigned int abs_symbol = Ns * frame_parms->symbols_per_slot + symbol;
   for (int idx_symb = Ns*frame_parms->symbols_per_slot; idx_symb <= abs_symbol; idx_symb++)
     rxdata_offset += (idx_symb%(0x7<<frame_parms->numerology_index)) ? nb_prefix_samples : nb_prefix_samples0;

openair1/PHY/NR_TRANSPORT/nr_prach.c

@@ -362,7 +362,7 @@ static void rx_nr_prach_ru_internal(prach_item_t *p,
     // Fixme: slot or slot makes no sense ???
     int slot2 = p->prach_sequence_length ? p->slot : p->slot;
     int idx = aa + beam_id * p->nb_rx;
-    c16_t *prach = (c16_t *)&rxdata[idx][fp->get_samples_slot_timestamp(slot2, fp, 0) + sample_offset_slot - N_TA_offset];
+    c16_t *prach = (c16_t *)&rxdata[idx][get_samples_slot_timestamp(fp, slot2) + sample_offset_slot - N_TA_offset];
 
     // do DFT
     c16_t *prach2 = prach + Ncp;

openair1/PHY/defs_nr_common.h

@@ -165,11 +165,6 @@ void init_prach_list(prach_list_t *);
 
 typedef struct NR_DL_FRAME_PARMS NR_DL_FRAME_PARMS;
 
-typedef uint32_t (*get_samples_per_slot_t)(int slot, const NR_DL_FRAME_PARMS *fp);
-typedef uint32_t (*get_slot_from_timestamp_t)(openair0_timestamp timestamp_rx, const NR_DL_FRAME_PARMS *fp);
-
-typedef uint32_t (*get_samples_slot_timestamp_t)(int slot, const NR_DL_FRAME_PARMS *fp, unsigned int sl_ahead);
-
 struct NR_DL_FRAME_PARMS {
   /// frequency range
   frequency_range_t freq_range;
@@ -225,12 +220,6 @@ struct NR_DL_FRAME_PARMS {
   uint16_t slots_per_frame;
   /// Number of samples in a subframe
   uint32_t samples_per_subframe;
-  /// Number of samples in current slot
-  get_samples_per_slot_t get_samples_per_slot;
-  /// slot calculation from timestamp
-  get_slot_from_timestamp_t get_slot_from_timestamp;
-  /// Number of samples before slot
-  get_samples_slot_timestamp_t get_samples_slot_timestamp;
   /// Number of samples in 0th and center slot of a subframe
   uint32_t samples_per_slot0;
   /// Number of samples in other slots of the subframe
@@ -340,5 +329,13 @@ typedef struct {
 uint32_t get_samples_symbol_duration(const NR_DL_FRAME_PARMS *fp, int slot, int start_symbol, int num_symbols);
 // Get timestamp of symbol within slot in samples
 uint32_t get_samples_symbol_timestamp(const NR_DL_FRAME_PARMS *fp, int slot, int symbol);
+// Get slot duration between two slot
+uint32_t get_samples_slot_duration(const NR_DL_FRAME_PARMS *fp, unsigned int start_slot, unsigned int num_slots);
+// Get timestamp of slot from start of frame
+uint32_t get_samples_slot_timestamp(const NR_DL_FRAME_PARMS *fp, unsigned int slot);
+// Get slot from timestamp
+uint32_t get_slot_from_timestamp(openair0_timestamp timestamp_rx, const NR_DL_FRAME_PARMS *fp);
+// Get number of samples in the slot
+uint32_t get_samples_per_slot(int slot, const NR_DL_FRAME_PARMS *fp);
 
 #endif