bugfix: fix timing advance

- remove global variables in the function lte_est_timing_advance_pusch
- do the smoothing logic that was in lte_est_timing_advance_pusch
  in rx_sdu (is it necessary? is it correct?)
- put back the value 100 in prach_procedures for the test on prach energy
- change the value of timing_advance_update

  it was:

     timing_advance_update                  = sync_pos - eNB->frame_parms.nb_prefix_samples/4; //to check

  it is now:

     timing_advance_update                  = sync_pos; // - eNB->frame_parms.nb_prefix_samples/4; //to check

  this should be checked somehow. The computation looked suspicious. Maybe
  the new one is wrong.

openair1/PHY/LTE_ESTIMATION/lte_adjust_sync.c

@@ -227,11 +227,8 @@ int lte_est_timing_advance(LTE_DL_FRAME_PARMS *frame_parms,
 
 int lte_est_timing_advance_pusch(PHY_VARS_eNB* eNB,uint8_t UE_id)
 {
-  static int first_run=1;
-  static int max_pos_fil2=0;
   int temp, i, aa, max_pos=0, max_val=0;
-  short Re,Im,coef=24576;
-  short ncoef = 32768 - coef;
+  short Re,Im;
 
   LTE_DL_FRAME_PARMS *frame_parms = &eNB->frame_parms;
   LTE_eNB_PUSCH *eNB_pusch_vars = eNB->pusch_vars[UE_id];
@@ -260,16 +257,9 @@ int lte_est_timing_advance_pusch(PHY_VARS_eNB* eNB,uint8_t UE_id)
   if (max_pos>frame_parms->ofdm_symbol_size/2)
     max_pos = max_pos-frame_parms->ofdm_symbol_size;
 
-  // filter position to reduce jitter
-  if (first_run == 1) {
-    first_run=0;
-    max_pos_fil2 = max_pos;
-  } else
-    max_pos_fil2 = ((max_pos_fil2 * coef) + (max_pos * ncoef)) >> 15;
-
   //#ifdef DEBUG_PHY
-  LOG_D(PHY,"frame %d: max_pos = %d, max_pos_fil = %d, sync_pos=%d\n",eNB->proc.frame_rx,max_pos,max_pos_fil2,sync_pos);
+  LOG_D(PHY,"frame %d: max_pos = %d, sync_pos=%d\n",eNB->proc.frame_rx,max_pos,sync_pos);
   //#endif //DEBUG_PHY
 
-  return(max_pos_fil2-sync_pos);
+  return max_pos - sync_pos;
 }

openair1/SCHED/phy_procedures_lte_eNb.c

@@ -663,7 +663,7 @@ void prach_procedures(PHY_VARS_eNB *eNB,
 
     {
       if ((eNB->prach_energy_counter == 100) && 
-          (max_preamble_energy[0] > eNB->measurements.prach_I0+200)) {
+          (max_preamble_energy[0] > eNB->measurements.prach_I0+100)) {
 
 	LOG_D(PHY,"[eNB %d/%d][RAPROC] Frame %d, subframe %d Initiating RA procedure with preamble %d, energy %d.%d dB, delay %d\n",
 	      eNB->Mod_id,
@@ -1524,7 +1524,7 @@ void fill_rx_indication(PHY_VARS_eNB *eNB,int UE_id,int frame,int subframe)
   pdu->data                              = eNB->ulsch[UE_id]->harq_processes[harq_pid]->b;
   // estimate timing advance for MAC
   sync_pos                               = lte_est_timing_advance_pusch(eNB,UE_id);
-  timing_advance_update                  = sync_pos - eNB->frame_parms.nb_prefix_samples/4; //to check
+  timing_advance_update                  = sync_pos; // - eNB->frame_parms.nb_prefix_samples/4; //to check
 
   //  if (timing_advance_update > 10) { dump_ulsch(eNB,frame,subframe,UE_id); exit(-1);}
   //  if (timing_advance_update < -10) { dump_ulsch(eNB,frame,subframe,UE_id); exit(-1);}

openair2/LAYER2/MAC/eNB_scheduler_ulsch.c

@@ -113,9 +113,13 @@ void rx_sdu(const module_id_t enb_mod_idP,
        UE_list->UE_sched_ctrl[UE_id].ul_inactivity_timer   = 0;
        UE_list->UE_sched_ctrl[UE_id].ul_failure_timer      = 0;
        UE_list->UE_sched_ctrl[UE_id].ul_scheduled         &= (~(1<<harq_pid));
-       /* don't take into account TA if timer is running */
-       if (UE_list->UE_sched_ctrl[UE_id].ta_timer == 0)
-         UE_list->UE_sched_ctrl[UE_id].ta_update             = timing_advance;
+       /* Update with smoothing: 3/4 of old value and 1/4 of new.
+        * This is the logic that was done in the function
+        * lte_est_timing_advance_pusch, maybe it's not necessary?
+        * maybe it's even not correct at all?
+        */
+       UE_list->UE_sched_ctrl[UE_id].ta_update             =
+           (UE_list->UE_sched_ctrl[UE_id].ta_update * 3 + timing_advance)/4;
        UE_list->UE_sched_ctrl[UE_id].pusch_snr[CC_idP]       = ul_cqi;
        UE_list->UE_sched_ctrl[UE_id].ul_consecutive_errors = 0;
        first_rb =  UE_list->UE_template[CC_idP][UE_id].first_rb_ul[harq_pid];