Making sample offset as cmd line parameter

for gNB its in L1 section of config file
for UE its a cmd line paramenter

executables/nr-uesoftmodem.c

@@ -242,6 +242,7 @@ void init_tpools(uint8_t nun_dlsch_threads) {
 }
 static void get_options(void) {
 
+  nrUE_params.ofdm_offset_divisor = 8;
   paramdef_t cmdline_params[] =CMDLINE_NRUEPARAMS_DESC ;
   int numparams = sizeof(cmdline_params)/sizeof(paramdef_t);
   config_process_cmdline( cmdline_params,numparams,NULL);
@@ -325,6 +326,8 @@ void set_options(int CC_id, PHY_VARS_NR_UE *UE){
 
   LOG_I(PHY, "Set UE nb_rx_antenna %d, nb_tx_antenna %d, threequarter_fs %d\n", fp->nb_antennas_rx, fp->nb_antennas_tx, fp->threequarter_fs);
 
+  fp->ofdm_offset_divisor = nrUE_params.ofdm_offset_divisor;
+
 }
 
 void init_openair0(void) {

executables/nr-uesoftmodem.h

@@ -8,7 +8,8 @@
 
 
 
-#define  CONFIG_HLP_DLSCH_PARA             "number of threads for dlsch processing 0 for no parallelization"
+#define  CONFIG_HLP_DLSCH_PARA             "number of threads for dlsch processing 0 for no parallelization\n"
+#define  CONFIG_HLP_OFFSET_DIV             "Divisor for computing OFDM symbol offset in Rx chain (num samples in CP/<the value>). Default value is 8. To set the sample offset to 0, set this value ~ 10e6\n"
 /***************************************************************************************************************************************/
 /* command line options definitions, CMDLINE_XXXX_DESC macros are used to initialize paramdef_t arrays which are then used as argument
    when calling config_get or config_getlist functions                                                                                 */
@@ -29,6 +30,7 @@
     {"usrp-args",                CONFIG_HLP_USRP_ARGS,   0,               strptr:(char **)&usrp_args,         defstrval:"type=b200", TYPE_STRING,   0},    \
     {"single-thread-disable",    CONFIG_HLP_NOSNGLT,     PARAMFLAG_BOOL,  iptr:&single_thread_flag,           defintval:1,           TYPE_INT,    0}, \
     {"dlsch-parallel",           CONFIG_HLP_DLSCH_PARA,  0,               iptr:(int32_t *)&nrUE_params.nr_dlsch_parallel,       defintval:0,           TYPE_UINT8,  0}, \
+    {"offset-divisor",           CONFIG_HLP_OFFSET_DIV,  0,               uptr:(uint32_t *)&nrUE_params.ofdm_offset_divisor,    defuintval:UINT_MAX,           TYPE_UINT32,  0}, \
     {"nr-dlsch-demod-shift",     CONFIG_HLP_DLSHIFT,     0,               iptr:(int32_t *)&nr_dlsch_demod_shift,    defintval:0,     TYPE_INT,    0}, \
     {"V" ,                       CONFIG_HLP_VCD,         PARAMFLAG_BOOL,  iptr:&vcdflag,                            defintval:0,     TYPE_INT,    0}, \
     {"rrc_config_path",          CONFIG_HLP_RRC_CFG_PATH,0,               strptr:(char **)&rrc_config_path,         defstrval:"./",  TYPE_STRING, 0} \
@@ -66,6 +68,7 @@
 
 typedef struct {
   uint64_t       optmask;   //mask to store boolean config options
+  uint32_t       ofdm_offset_divisor; // Divisor for sample offset computation for each OFDM symbol
   uint8_t        nr_dlsch_parallel; // number of threads for dlsch decoding, 0 means no parallelization
   tpool_t        Tpool;             // thread pool 
 } nrUE_params_t;

openair1/PHY/INIT/nr_init.c

@@ -483,6 +483,7 @@ void nr_phy_config_request_sim(PHY_VARS_gNB *gNB,
   gNB_config->carrier_config.dl_bandwidth.value = config_bandwidth(mu, N_RB_DL, fp->nr_band);
 
   nr_init_frame_parms(gNB_config, fp);
+  fp->ofdm_offset_divisor = UINT_MAX;
   gNB->configured    = 1;
   LOG_I(PHY,"gNB configured\n");
 }
@@ -534,6 +535,7 @@ void nr_phy_config_request(NR_PHY_Config_t *phy_config) {
 //  }
   RC.gNB[Mod_id]->configured     = 1;
 
+  fp->ofdm_offset_divisor = RC.gNB[Mod_id]->ofdm_offset_divisor;
   init_symbol_rotation(fp);
   init_timeshift_rotation(fp);
 

openair1/PHY/MODULATION/nr_modulation.c

@@ -762,7 +762,7 @@ void init_timeshift_rotation(NR_DL_FRAME_PARMS *fp)
   for (i = 0; i < fp->ofdm_symbol_size/2; i++) {
     timeshift_symbol_rotation = fp->timeshift_symbol_rotation[0];
     f = fd * i;
-    t0 = Ncp0 / 8;
+    t0 = Ncp0 / fp->ofdm_offset_divisor;
     poff = 2 * M_PI * -t0 * Tc * f;
     exp_re = cos(poff);
     exp_im = sin(-poff);
@@ -770,7 +770,7 @@ void init_timeshift_rotation(NR_DL_FRAME_PARMS *fp)
     timeshift_symbol_rotation[i*2+1] = (int16_t)floor(exp_im * 32767);
 
     timeshift_symbol_rotation = fp->timeshift_symbol_rotation[1];
-    t0 = Ncp1 / 8;
+    t0 = Ncp1 / fp->ofdm_offset_divisor;
     poff = 2 * M_PI * -t0 * Tc * f;
     exp_re = cos(poff);
     exp_im = sin(-poff);
@@ -779,8 +779,8 @@ void init_timeshift_rotation(NR_DL_FRAME_PARMS *fp)
 
     if (i < 10)
       LOG_I(PHY,"Timeshift symbol rotation %d => (%d,%d) %f\n",i,
-            fp->timeshift_symbol_rotation[1][i*2],
-            fp->timeshift_symbol_rotation[1][i*2+1],
+            fp->timeshift_symbol_rotation[0][i*2],
+            fp->timeshift_symbol_rotation[0][i*2+1],
             poff);
 
   }
@@ -789,25 +789,25 @@ void init_timeshift_rotation(NR_DL_FRAME_PARMS *fp)
   for (int j = fp->ofdm_symbol_size-1; j > fp->ofdm_symbol_size/2-1; j--) {
     timeshift_symbol_rotation = fp->timeshift_symbol_rotation[0];
     f = -fd * i;
-    t0 = Ncp0 / 8;
+    t0 = Ncp0 / fp->ofdm_offset_divisor;
     poff = 2 * M_PI * -t0 * Tc * f;
     exp_re = cos(poff);
     exp_im = sin(-poff);
-    timeshift_symbol_rotation[j*2] = (int16_t)floor(exp_re * 32767);
-    timeshift_symbol_rotation[j*2+1] = (int16_t)floor(exp_im * 32767);
+    timeshift_symbol_rotation[j*2] = (int16_t)ceil(exp_re * 32767);
+    timeshift_symbol_rotation[j*2+1] = (int16_t)ceil(exp_im * 32767);
 
     timeshift_symbol_rotation = fp->timeshift_symbol_rotation[1];
-    t0 = Ncp1 / 8;
+    t0 = Ncp1 / fp->ofdm_offset_divisor;
     poff = 2 * M_PI * -t0 * Tc * f;
     exp_re = cos(poff);
     exp_im = sin(-poff);
-    timeshift_symbol_rotation[j*2] = (int16_t)floor(exp_re * 32767);
-    timeshift_symbol_rotation[j*2+1] = (int16_t)floor(exp_im * 32767);
+    timeshift_symbol_rotation[j*2] = (int16_t)ceil(exp_re * 32767);
+    timeshift_symbol_rotation[j*2+1] = (int16_t)ceil(exp_im * 32767);
 
     if (j > fp->ofdm_symbol_size-10-1)
       LOG_I(PHY,"Timeshift symbol rotation %d => (%d,%d) %f\n",-i,
-            fp->timeshift_symbol_rotation[1][j*2],
-            fp->timeshift_symbol_rotation[1][j*2+1],
+            fp->timeshift_symbol_rotation[0][j*2],
+            fp->timeshift_symbol_rotation[0][j*2+1],
             poff);
     i++;
   }

openair1/PHY/MODULATION/slot_fep_nr.c

@@ -107,7 +107,7 @@ int nr_slot_fep(PHY_VARS_NR_UE *ue,
   rx_offset += frame_parms->ofdm_symbol_size * symbol;
 
   // use OFDM symbol from within 1/8th of the CP to avoid ISI
-  rx_offset -= nb_prefix_samples / 8;
+  rx_offset -= (nb_prefix_samples / frame_parms->ofdm_offset_divisor);
 
 #ifdef DEBUG_FEP
   //  if (ue->frame <100)
@@ -158,11 +158,7 @@ int nr_slot_fep(PHY_VARS_NR_UE *ue,
 		      frame_parms->ofdm_symbol_size,
 		      15);
 
-    int16_t *shift_rot;
-    if (symb_offset+symbol == (7 * (1 << frame_parms->numerology_index)))
-      shift_rot = frame_parms->timeshift_symbol_rotation[0];
-    else
-      shift_rot = frame_parms->timeshift_symbol_rotation[1];
+    int16_t *shift_rot = frame_parms->timeshift_symbol_rotation[0];
 
     multadd_cpx_vector((int16_t *)&common_vars->common_vars_rx_data_per_thread[proc->thread_id].rxdataF[aa][frame_parms->ofdm_symbol_size*symbol],
           shift_rot,
@@ -309,7 +305,7 @@ int nr_slot_fep_ul(NR_DL_FRAME_PARMS *frame_parms,
   // offset of n-th OFDM symbol
   rxdata_offset += symbol * (frame_parms->ofdm_symbol_size + nb_prefix_samples);
   // use OFDM symbol from within 1/8th of the CP to avoid ISI
-  rxdata_offset -= nb_prefix_samples / 8;
+  rxdata_offset -= (nb_prefix_samples / frame_parms->ofdm_offset_divisor);
 
   int16_t *rxdata_ptr;
 
@@ -370,11 +366,7 @@ void apply_nr_rotation_ul(NR_DL_FRAME_PARMS *frame_parms,
 		      length,
 		      15);
 
-    int16_t *shift_rot;
-    if (symb_offset+symbol == (7 * (1 << frame_parms->numerology_index)))
-      shift_rot = frame_parms->timeshift_symbol_rotation[0];
-    else
-      shift_rot = frame_parms->timeshift_symbol_rotation[1];
+    int16_t *shift_rot = frame_parms->timeshift_symbol_rotation[0];
 
     multadd_cpx_vector((int16_t *)&rxdataF[frame_parms->ofdm_symbol_size*symbol],
           shift_rot,

openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c

@@ -45,7 +45,7 @@ int nr_est_timing_advance_pusch(PHY_VARS_gNB* gNB, int UE_id)
   NR_gNB_PUSCH *gNB_pusch_vars   = gNB->pusch_vars[UE_id];
   int32_t **ul_ch_estimates_time = gNB_pusch_vars->ul_ch_estimates_time;
   
-  int sync_pos = frame_parms->nb_prefix_samples / 8;
+  int sync_pos = frame_parms->nb_prefix_samples / frame_parms->ofdm_offset_divisor;
 
   for (i = 0; i < frame_parms->ofdm_symbol_size; i++) {
     int temp = 0;

openair1/PHY/NR_UE_ESTIMATION/nr_adjust_synch_ue.c

@@ -82,7 +82,7 @@ void nr_adjust_synch_ue(NR_DL_FRAME_PARMS *frame_parms,
   // do not filter to have proactive timing adjustment
   //max_pos_fil = max_pos;
 
-      diff = max_pos_fil - (frame_parms->nb_prefix_samples>>3);
+      diff = max_pos_fil - (frame_parms->nb_prefix_samples / frame_parms->ofdm_offset_divisor);
 
       if (frame_parms->freq_range==nr_FR2) 
 		sync_offset = 2;

openair1/PHY/defs_gNB.h

@@ -776,6 +776,8 @@ typedef struct PHY_VARS_gNB_s {
 
   uint32_t max_peak_val;
 
+  /// OFDM symbol offset divisor for UL
+  uint32_t ofdm_offset_divisor;
   /// \brief sinr for all subcarriers of the current link (used only for abstraction).
   /// first index: ? [0..N_RB_DL*12[
   double *sinr_dB;

openair1/PHY/defs_nr_common.h

@@ -365,6 +365,8 @@ struct NR_DL_FRAME_PARMS {
   uint8_t ssb_index;
   /// PBCH polar encoder params
   t_nrPolar_params pbch_polar_params;
+  /// OFDM symbol offset divisor for UL
+  uint32_t ofdm_offset_divisor;
 };
 
 

openair1/SIMULATION/NR_PHY/dlsim.c

@@ -619,6 +619,7 @@ int main(int argc, char **argv)
   memset(RC.gNB[0],0,sizeof(PHY_VARS_gNB));
 
   gNB = RC.gNB[0];
+  gNB->ofdm_offset_divisor = UINT_MAX;
   frame_parms = &gNB->frame_parms; //to be initialized I suppose (maybe not necessary for PBCH)
   frame_parms->nb_antennas_tx = n_tx;
   frame_parms->nb_antennas_rx = n_rx;

openair1/SIMULATION/NR_PHY/pbchsim.c

@@ -109,7 +109,9 @@ void nr_phy_config_request_sim_pbchsim(PHY_VARS_gNB *gNB,
 
   gNB_config->carrier_config.dl_bandwidth.value = config_bandwidth(mu, N_RB_DL, fp->nr_band);
 
+  fp->ofdm_offset_divisor = UINT_MAX;
   nr_init_frame_parms(gNB_config, fp);
+  init_timeshift_rotation(fp);
 
   init_symbol_rotation(fp);
 
@@ -405,6 +407,7 @@ int main(int argc, char **argv)
   RC.gNB = (PHY_VARS_gNB**) malloc(sizeof(PHY_VARS_gNB *));
   RC.gNB[0] = malloc(sizeof(PHY_VARS_gNB));
   gNB = RC.gNB[0];
+  gNB->ofdm_offset_divisor = UINT_MAX;
   frame_parms = &gNB->frame_parms; //to be initialized I suppose (maybe not necessary for PBCH)
   frame_parms->nb_antennas_tx = n_tx;
   frame_parms->nb_antennas_rx = n_rx;

openair1/SIMULATION/NR_PHY/ulsim.c

@@ -616,6 +616,7 @@ int main(int argc, char **argv)
   RC.gNB = (PHY_VARS_gNB **) malloc(sizeof(PHY_VARS_gNB *));
   RC.gNB[0] = calloc(1,sizeof(PHY_VARS_gNB));
   gNB = RC.gNB[0];
+  gNB->ofdm_offset_divisor = UINT_MAX;
   gNB->threadPool = (tpool_t*)malloc(sizeof(tpool_t));
   gNB->respDecode = (notifiedFIFO_t*) malloc(sizeof(notifiedFIFO_t));
   char tp_param[] = "n";

openair2/GNB_APP/L1_nr_paramdef.h

@@ -47,6 +47,7 @@
 #define CONFIG_STRING_L1_REMOTE_N_PORTD                    "remote_n_portd"
 #define CONFIG_STRING_L1_TRANSPORT_N_PREFERENCE            "tr_n_preference"
 #define CONFIG_STRING_L1_PUSCH_PROC_THREADS                "pusch_proc_threads"
+#define CONFIG_STRING_L1_OFDM_OFFSET_DIVISOR               "ofdm_offset_divisor"
 
 /*----------------------------------------------------------------------------------------------------------------------------------------------------*/
 /*                                            L1 configuration parameters                                                                             */
@@ -62,7 +63,8 @@
 {CONFIG_STRING_L1_REMOTE_N_PORTC,                    NULL,      0,         uptr:NULL,           defintval:50030,           TYPE_UINT,     0},         \
 {CONFIG_STRING_L1_LOCAL_N_PORTD,                     NULL,      0,         uptr:NULL,           defintval:50031,           TYPE_UINT,     0},         \
 {CONFIG_STRING_L1_REMOTE_N_PORTD,                    NULL,      0,         uptr:NULL,           defintval:50031,           TYPE_UINT,     0},         \
-{CONFIG_STRING_L1_PUSCH_PROC_THREADS,                NULL,      0,         uptr:NULL,           defintval:3,               TYPE_UINT,     0} \
+{CONFIG_STRING_L1_PUSCH_PROC_THREADS,                NULL,      0,         uptr:NULL,           defintval:3,               TYPE_UINT,     0}, \
+{CONFIG_STRING_L1_OFDM_OFFSET_DIVISOR,               NULL,      0,         uptr:NULL,           defuintval:UINT_MAX,       TYPE_UINT,     0} \
 }
 #define L1_CC_IDX                                          0
 #define L1_TRANSPORT_N_PREFERENCE_IDX                      1
@@ -74,6 +76,7 @@
 #define L1_LOCAL_N_PORTD_IDX                               7
 #define L1_REMOTE_N_PORTD_IDX                              8
 #define L1_PUSCH_PROC_THREADS                              9
+#define L1_OFDM_OFFSET_DIVISOR                             10
 
 /*----------------------------------------------------------------------------------------------------------------------------------------------------*/
 #endif

openair2/GNB_APP/gnb_config.c

@@ -591,6 +591,7 @@ void RCconfig_NR_L1(void) {
       }
 
       RC.gNB[j]->pusch_proc_threads = *(L1_ParamList.paramarray[j][L1_PUSCH_PROC_THREADS].uptr);
+      RC.gNB[j]->ofdm_offset_divisor = *(L1_ParamList.paramarray[j][L1_OFDM_OFFSET_DIVISOR].uptr);
 
       if(strcmp(*(L1_ParamList.paramarray[j][L1_TRANSPORT_N_PREFERENCE_IDX].strptr), "local_mac") == 0) {
         //sf_ahead = 2; // Need 4 subframe gap between RX and TX

targets/PROJECTS/GENERIC-LTE-EPC/CONF/gnb.band78.tm1.106PRB.usrpn300.conf

@@ -235,6 +235,7 @@ L1s = (
 	num_cc = 1;
 	tr_n_preference = "local_mac";
 	pusch_proc_threads = 8;
+  ofdm_offset_divisor = 8;
 	}
 );