Merge remote-tracking branch 'origin/better-C-style-pss-sss' into integration_2026_w12 (!3724)

Better c style pss sss

there is a commit to simplify code for pss and sss detection
then a second commit to test a idea: detect SSS with a advantage for SSS
in phase with PSS

openair1/PHY/NR_REFSIG/sss_nr.h

@@ -61,38 +61,9 @@
 
 #define SSS_METRIC_FLOOR_NR   (30000)
 
-/************** VARIABLES *****************************************/
-
-#define PHASE_HYPOTHESIS_NUMBER       (16)
-#define INDEX_NO_PHASE_DIFFERENCE (3) /* this is for no phase shift case */
-
-/************** FUNCTION ******************************************/
-
-static const c16_t phase_nr[PHASE_HYPOTHESIS_NUMBER] = {
-    // {pi/3 ---- pi/3, -pi/3 ---- pi/3}
-    {16384, -28377},
-    {20173, -25821},
-    {23571, -22762},
-    {26509, -19260},
-    {28932, -15383},
-    {30791, -11207},
-    {32051, -6813},
-    {32687, -2286},
-    {32687, 2286},
-    {32051, 6813},
-    {30791, 11207},
-    {28932, 15383},
-    {26509, 19260},
-    {23571, 22762},
-    {20173, 25821},
-    {16384, 28377}};
-
 void init_context_sss_nr(int amp);
 void free_context_sss_nr(void);
 
-void insert_sss_nr(int16_t *sss_time,
-                   NR_DL_FRAME_PARMS *frame_parms);
-
 bool rx_sss_nr(const NR_DL_FRAME_PARMS *frame_parms,
                int nid2,
                int target_Nid_cell,

openair1/PHY/NR_TRANSPORT/nr_sss.c

@@ -23,11 +23,7 @@
 
 //#define NR_SSS_DEBUG
 
-int nr_generate_sss(  c16_t *txdataF,
-                      int16_t amp,
-                      uint8_t ssb_start_symbol,
-                      nfapi_nr_config_request_scf_t* config,
-                      NR_DL_FRAME_PARMS *frame_parms)
+int nr_generate_sss(c16_t *txdataF, int16_t amp, uint8_t ssb_start_symbol, int Nid, NR_DL_FRAME_PARMS *frame_parms)
 {
   int16_t x0[NR_SSS_LENGTH];
   int16_t x1[NR_SSS_LENGTH];
@@ -35,7 +31,6 @@ int nr_generate_sss(  c16_t *txdataF,
   const int x1_initial[7] = { 1, 0, 0, 0, 0, 0, 0 };
 
   /// Sequence generation
-  int Nid = config->cell_config.phy_cell_id.value;
   int Nid2 = Nid % 3;
   int Nid1 = (Nid - Nid2)/3;
 
@@ -59,13 +54,11 @@ int nr_generate_sss(  c16_t *txdataF,
   /// Resource mapping
 
   // SSS occupies a predefined position (subcarriers 56-182, symbol 2) within the SSB block starting from
-  int k = frame_parms->ssb_start_subcarrier + 56;
-  int l = ssb_start_symbol + 2;
+  c16_t *tx = txdataF + (ssb_start_symbol + 2) * frame_parms->ofdm_symbol_size + frame_parms->ssb_start_subcarrier + 56;
 
   for (int i = 0; i < NR_SSS_LENGTH; i++) {
     int16_t d_sss = (1 - 2*x0[(i + m0) % NR_SSS_LENGTH] ) * (1 - 2*x1[(i + m1) % NR_SSS_LENGTH] ) * 23170;
-    ((int16_t*)txdataF)[2*(l*frame_parms->ofdm_symbol_size + k)] = (((int16_t)amp) * d_sss) >> 15;
-    k++;
+    *tx++ = (c16_t){.r = (amp * d_sss) >> 15};
   }
 #ifdef NR_SSS_DEBUG
   //  write_output("sss_0.m", "sss_0", (void*)txdataF[0][l*frame_parms->ofdm_symbol_size], frame_parms->ofdm_symbol_size, 1, 1);

openair1/PHY/NR_TRANSPORT/nr_transport_proto.h

@@ -60,11 +60,7 @@ int nr_generate_pss(c16_t *txdataF,
 @param
 @returns 0 on success
  */
-int nr_generate_sss(c16_t *txdataF,
-                    int16_t amp,
-                    uint8_t ssb_start_symbol,
-                    nfapi_nr_config_request_scf_t *config,
-                    NR_DL_FRAME_PARMS *frame_parms);
+int nr_generate_sss(c16_t *txdataF, int16_t amp, uint8_t ssb_start_symbol, int nid, NR_DL_FRAME_PARMS *frame_parms);
 
 /*!
 \fn void nr_generate_pbch_dmrs

openair1/PHY/NR_UE_TRANSPORT/nr_initial_sync_sl.c

@@ -161,7 +161,6 @@ static void sl_nr_extract_sss(PHY_VARS_NR_UE *ue,
   NR_DL_FRAME_PARMS *sl_fp = &ue->SL_UE_PHY_PARAMS.sl_frame_params;
   int16_t *d;
   uint16_t Nid1 = 0;
-  uint8_t phase;
   c16_t *rxF_ext;
 
   for (int aarx = 0; aarx < sl_fp->nb_antennas_rx; aarx++) {
@@ -260,15 +259,16 @@ static void sl_nr_extract_sss(PHY_VARS_NR_UE *ue,
   c16_t *sss = &sss_ext[0][0][0];
 
   for (uint16_t id1 = 0; id1 < SL_NR_NUM_IDs_IN_SSS; id1++) { // all possible SSS Nid1 values
-    for (phase = 0; phase < PHASE_HYPOTHESIS_NUMBER; phase++) { // phase offset between PSS and SSS
+    for (int phase = -15; phase < 16; phase += 2) { // phase offset between PSS and SSS
 
       int32_t metric = 0, metric_re = 0;
-
+      const c64_t rot = (c64_t){round(cos(M_PI / 3 / 15 * (phase)) * 32767), round(sin(M_PI / 3 / 15 * (phase)) * 32767)};
       d = (int16_t *)&ue->SL_UE_PHY_PARAMS.init_params.sl_sss_for_sync[Nid2 * SL_NR_NUM_IDs_IN_SSS + id1];
 
       // This is the inner product using one particular value of each unknown parameter
       for (int i = 0; i < SL_NR_SSS_SEQUENCE_LENGTH; i++) {
-        metric_re += d[i] * (((int64_t)phase_nr[phase].r * sss[i].r - phase_nr[phase].i * sss[i].i) >> 15);
+        // metric is only real part because sss is a pure real signal (imaginary is 0)
+        metric_re += d[i] * ((rot.r * sss[i].r - rot.i * sss[i].i) >> 15);
       }
 
       metric = metric_re;

openair1/SCHED_NR/phy_procedures_nr_gNB.c

@@ -156,7 +156,7 @@ void nr_common_signal_procedures(PHY_VARS_gNB *gNB, int frame, int slot, const n
                                       bitmap);
 
   nr_generate_pss(txdataF[beam_nb][0], gNB->TX_AMP, ssb_start_symbol, cfg, fp);
-  nr_generate_sss(txdataF[beam_nb][0], gNB->TX_AMP, ssb_start_symbol, cfg, fp);
+  nr_generate_sss(txdataF[beam_nb][0], gNB->TX_AMP, ssb_start_symbol, cfg->cell_config.phy_cell_id.value, fp);
 
   uint16_t slots_per_hf = (fp->slots_per_frame) >> 1;
   int n_hf = slot < slots_per_hf ? 0 : 1;