lte_sync_time.c

/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
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 */

/* file: lte_sync_time.c
   purpose: coarse timing synchronization for LTE (using PSS)
   author: florian.kaltenberger@eurecom.fr, oscar.tonelli@yahoo.it
   date: 22.10.2009
*/

//#include <string.h>
#include <math.h>
#include "PHY/defs_UE.h"
#include "PHY/phy_extern_ue.h"
#include "PHY/LTE_REFSIG/lte_refsig.h"

// Note: this is for prototype of generate_drs_pusch (OTA synchronization of RRUs)
#include "PHY/LTE_UE_TRANSPORT/transport_proto_ue.h"

static struct complex16 *primary_synch0_time __attribute__((aligned(32)));
static struct complex16 *primary_synch1_time __attribute__((aligned(32)));
static struct complex16 *primary_synch2_time __attribute__((aligned(32)));

static void doIdft(int size, short *in, short *out) {
  switch (size) {
  case 6:
      idft(IDFT_128,in,out,1);
    break;

  case 25:
      idft(IDFT_512,in,out,1);
    break;

  case 50:
      idft(IDFT_1024,in,out,1);
    break;
    
  case 75:
      idft(IDFT_1536,in,out,1);
    break;

  case 100:
      idft(IDFT_2048,in,out,1);
    break;

  default:
      LOG_E(PHY,"Unsupported N_RB_DL %d\n",size);
      abort();
    break;
    }
  }

static void copyPrimary( struct complex16 *out, struct complex16 *in, int ofdmSize) {
  int k=ofdmSize-36;
    
  for (int i=0; i<72; i++) {
    out[k].r = in[i].r>>1;  //we need to shift input to avoid overflow in fft
    out[k].i = in[i].i>>1;
    k++;

    if (k >= ofdmSize) {
      k++;  // skip DC carrier
      k-=ofdmSize;
    }
  }
  }

int lte_sync_time_init(LTE_DL_FRAME_PARMS *frame_parms ) { // LTE_UE_COMMON *common_vars
  struct complex16 syncF_tmp[2048]__attribute__((aligned(32)))= {{0}};
  int sz=frame_parms->ofdm_symbol_size*sizeof(*primary_synch0_time);
  AssertFatal( NULL != (primary_synch0_time = (struct complex16 *)malloc16(sz)),"");
  bzero(primary_synch0_time,sz);
  AssertFatal( NULL != (primary_synch1_time = (struct complex16 *)malloc16(sz)),"");
  bzero(primary_synch1_time,sz);
  AssertFatal( NULL != (primary_synch2_time = (struct complex16 *)malloc16(sz)),"");
  bzero(primary_synch2_time,sz);
  // generate oversampled sync_time sequences
  copyPrimary( syncF_tmp, (struct complex16 *) primary_synch0, frame_parms->ofdm_symbol_size);
  doIdft(frame_parms->N_RB_DL, (short *)syncF_tmp,(short *)primary_synch0_time);
  copyPrimary( syncF_tmp, (struct complex16 *) primary_synch1, frame_parms->ofdm_symbol_size);
  doIdft(frame_parms->N_RB_DL, (short *)syncF_tmp,(short *)primary_synch1_time);
  copyPrimary( syncF_tmp, (struct complex16 *) primary_synch2, frame_parms->ofdm_symbol_size);
  doIdft(frame_parms->N_RB_DL, (short *)syncF_tmp,(short *)primary_synch2_time);

  if ( LOG_DUMPFLAG(DEBUG_LTEESTIM)){
    LOG_M("primary_sync0.m","psync0",primary_synch0_time,frame_parms->ofdm_symbol_size,1,1);
    LOG_M("primary_sync1.m","psync1",primary_synch1_time,frame_parms->ofdm_symbol_size,1,1);
    LOG_M("primary_sync2.m","psync2",primary_synch2_time,frame_parms->ofdm_symbol_size,1,1);
  }

  return (1);
}


void lte_sync_time_free(void) {
  if (primary_synch0_time) {
    LOG_D(PHY,"Freeing primary_sync0_time ...\n");
    free(primary_synch0_time);
  }

  if (primary_synch1_time) {
    LOG_D(PHY,"Freeing primary_sync1_time ...\n");
    free(primary_synch1_time);
  }

  if (primary_synch2_time) {
    LOG_D(PHY,"Freeing primary_sync2_time ...\n");
    free(primary_synch2_time);
  }

  primary_synch0_time = NULL;
  primary_synch1_time = NULL;
  primary_synch2_time = NULL;
}


static inline int abs32(int x) {
  return (((int)((short*)&x)[0])*((int)((short*)&x)[0]) + ((int)((short*)&x)[1])*((int)((short*)&x)[1]));
}

static inline double absF(struct complexd x) {
  return x.r*x.r+x.i*x.i;
}

#define complexNull(c) bzero((void*) &(c), sizeof(c))

#define SHIFT 17


int lte_sync_time(int **rxdata, ///rx data in time domain
                  LTE_DL_FRAME_PARMS *frame_parms,
                  int *eNB_id) {
  // perform a time domain correlation using the oversampled sync sequence
  unsigned int n, ar, s, peak_pos, peak_val, sync_source;
  int result,result2;
  struct complexd sync_out[3]= {{0}}, sync_out2[3]= {{0}};
  int length =   LTE_NUMBER_OF_SUBFRAMES_PER_FRAME*frame_parms->samples_per_tti>>1;
  peak_val = 0;
  peak_pos = 0;
  sync_source = 0;

  for (n=0; n<length; n+=4) {
    for (s=0; s<3; s++) {
      complexNull(sync_out[s]);
      complexNull(sync_out2[s]);
    }

    //    if (n<(length-frame_parms->ofdm_symbol_size-frame_parms->nb_prefix_samples)) {
    if (n<(length-frame_parms->ofdm_symbol_size)) {
      //calculate dot product of primary_synch0_time and rxdata[ar][n] (ar=0..nb_ant_rx) and store the sum in temp[n];
      for (ar=0; ar<frame_parms->nb_antennas_rx; ar++) {
        result  = dot_product((short *)primary_synch0_time, (short *) &(rxdata[ar][n]), frame_parms->ofdm_symbol_size, SHIFT);
        result2 = dot_product((short *)primary_synch0_time, (short *) &(rxdata[ar][n+length]), frame_parms->ofdm_symbol_size, SHIFT);
        sync_out[0].r += ((short *) &result)[0];
        sync_out[0].i += ((short *) &result)[1];
        sync_out2[0].r += ((short *) &result2)[0];
        sync_out2[0].i += ((short *) &result2)[1];
      }

      for (ar=0; ar<frame_parms->nb_antennas_rx; ar++) {
        result = dot_product((short *)primary_synch1_time, (short *) &(rxdata[ar][n]), frame_parms->ofdm_symbol_size, SHIFT);
        result2 = dot_product((short *)primary_synch1_time, (short *) &(rxdata[ar][n+length]), frame_parms->ofdm_symbol_size, SHIFT);
        sync_out[1].r += ((short *) &result)[0];
        sync_out[1].i += ((short *) &result)[1];
        sync_out2[1].r += ((short *) &result2)[0];
        sync_out2[1].i += ((short *) &result2)[1];
      }

      for (ar=0; ar<frame_parms->nb_antennas_rx; ar++) {
        result = dot_product((short *)primary_synch2_time, (short *) &(rxdata[ar][n]), frame_parms->ofdm_symbol_size, SHIFT);
        result2 = dot_product((short *)primary_synch2_time, (short *) &(rxdata[ar][n+length]), frame_parms->ofdm_symbol_size, SHIFT);
        sync_out[2].r += ((short *) &result)[0];
        sync_out[2].i += ((short *) &result)[1];
        sync_out2[2].r += ((short *) &result2)[0];
        sync_out2[2].i += ((short *) &result2)[1];
      }
    }

    // calculate the absolute value of sync_corr[n]

    for (s=0; s<3; s++) {
      double tmp = absF(sync_out[s]) + absF(sync_out2[s]);

      if (tmp>peak_val) {
        peak_val = tmp;
        peak_pos = n;
        sync_source = s;
        /*
        printf("s %d: n %d sync_out %d, sync_out2  %d (sync_corr %d,%d), (%d,%d) (%d,%d)\n",s,n,abs32(sync_out[s]),abs32(sync_out2[s]),sync_corr_ue0[n],
               sync_corr_ue0[n+length],((int16_t*)&sync_out[s])[0],((int16_t*)&sync_out[s])[1],((int16_t*)&sync_out2[s])[0],((int16_t*)&sync_out2[s])[1]);
        */
      }
    }
  }

  *eNB_id = sync_source;
  LOG_I(PHY,"[UE] lte_sync_time: Sync source = %d, Peak found at pos %d, val = %d (%d dB)\n",sync_source,peak_pos,peak_val/2,dB_fixed(peak_val/2)/2);
  return(peak_pos);
}


int ru_sync_time_init(RU_t *ru) { // LTE_UE_COMMON *common_vars
  /*
  int16_t dmrs[2048];
  int16_t *dmrsp[2] = {dmrs,NULL};
  */
  int32_t dmrs[ru->frame_parms->ofdm_symbol_size*14] __attribute__((aligned(32)));
  //int32_t *dmrsp[2] = {&dmrs[(3-ru->frame_parms->Ncp)*ru->frame_parms->ofdm_symbol_size],NULL};
  int32_t *dmrsp[2] = {&dmrs[0],NULL};
  generate_ul_ref_sigs();
  ru->dmrssync = (int16_t *)malloc16_clear(ru->frame_parms->ofdm_symbol_size*2*sizeof(int16_t));
  ru->dmrs_corr = (uint64_t *)malloc16_clear(ru->frame_parms->samples_per_tti*10*sizeof(uint64_t));
  generate_drs_pusch(NULL,
                     NULL,
                     ru->frame_parms,
                     dmrsp,
                     0,
                     AMP,
                     0,
                     0,
                     ru->frame_parms->N_RB_DL,
                     0);

  switch (ru->frame_parms->N_RB_DL) {
    case 6:
      idft(IDFT_128,(int16_t *)(&dmrsp[0][3*ru->frame_parms->ofdm_symbol_size]),
           ru->dmrssync, /// complex output
           1);
      break;

    case 25:
      idft(IDFT_512,(int16_t *)(&dmrsp[0][3*ru->frame_parms->ofdm_symbol_size]),
           ru->dmrssync, /// complex output
           1);
      break;

    case 50:
      idft(IDFT_1024,(int16_t *)(&dmrsp[0][3*ru->frame_parms->ofdm_symbol_size]),
           ru->dmrssync, /// complex output
           1);
      break;

    case 75:
      idft(IDFT_1536,(int16_t *)(&dmrsp[0][3*ru->frame_parms->ofdm_symbol_size]),
           ru->dmrssync,
           1); /// complex output
      break;

    case 100:
      idft(IDFT_2048,(int16_t *)(&dmrsp[0][3*ru->frame_parms->ofdm_symbol_size]),
           ru->dmrssync, /// complex output
           1);
      break;

    default:
      AssertFatal(1==0,"Unsupported N_RB_DL %d\n",ru->frame_parms->N_RB_DL);
      break;
  }

  return(0);
}


void ru_sync_time_free(RU_t *ru) {
  AssertFatal(ru->dmrssync!=NULL,"ru->dmrssync is NULL\n");
  free(ru->dmrssync);

  if (ru->dmrs_corr)
    free(ru->dmrs_corr);
}

//#define DEBUG_PHY

int lte_sync_time_eNB(int32_t **rxdata, ///rx data in time domain
                      LTE_DL_FRAME_PARMS *frame_parms,
                      uint32_t length,
                      uint32_t *peak_val_out,
                      uint32_t *sync_corr_eNB) {
  // perform a time domain correlation using the oversampled sync sequence
  unsigned int n, ar, peak_val, peak_pos;
  uint64_t mean_val;
  int result;
  short *primary_synch_time;
  int eNB_id = frame_parms->Nid_cell%3;

  // LOG_E(PHY,"[SYNC TIME] Calling sync_time_eNB(%p,%p,%d,%d)\n",rxdata,frame_parms,eNB_id,length);
  if (sync_corr_eNB == NULL) {
    LOG_E(PHY,"[SYNC TIME] sync_corr_eNB not yet allocated! Exiting.\n");
    return(-1);
  }

  switch (eNB_id) {
    case 0:
      primary_synch_time = (short *)primary_synch0_time;
      break;

    case 1:
      primary_synch_time = (short *)primary_synch1_time;
      break;

    case 2:
      primary_synch_time = (short *)primary_synch2_time;
      break;

    default:
      LOG_E(PHY,"[SYNC TIME] Illegal eNB_id!\n");
      return (-1);
  }

  peak_val = 0;
  peak_pos = 0;
  mean_val = 0;

  for (n=0; n<length; n+=4) {
    sync_corr_eNB[n] = 0;

    if (n<(length-frame_parms->ofdm_symbol_size-frame_parms->nb_prefix_samples)) {
      //calculate dot product of primary_synch0_time and rxdata[ar][n] (ar=0..nb_ant_rx) and store the sum in temp[n];
      for (ar=0; ar<frame_parms->nb_antennas_rx; ar++)  {
        result = dot_product((short *)primary_synch_time, (short *) &(rxdata[ar][n]), frame_parms->ofdm_symbol_size, SHIFT);
        //((short*)sync_corr)[2*n]   += ((short*) &result)[0];
        //((short*)sync_corr)[2*n+1] += ((short*) &result)[1];
        sync_corr_eNB[n] += abs32(result);
      }
    }

    /*
    if (eNB_id == 2) {
      printf("sync_time_eNB %d : %d,%d (%d)\n",n,sync_corr_eNB[n],mean_val,
       peak_val);
    }
    */
    mean_val += sync_corr_eNB[n];

    if (sync_corr_eNB[n]>peak_val) {
      peak_val = sync_corr_eNB[n];
      peak_pos = n;
    }
  }

  mean_val/=length;
  *peak_val_out = peak_val;

  if (peak_val <= (40*(uint32_t)mean_val)) {
    LOG_I(PHY,"[SYNC TIME] No peak found (%u,%u,%"PRIu64",%"PRIu64")\n",peak_pos,peak_val,mean_val,40*mean_val);
    return(-1);
  } else {
    LOG_I(PHY,"[SYNC TIME] Peak found at pos %u, val = %u, mean_val = %"PRIu64"\n",peak_pos,peak_val,mean_val);
    return(peak_pos);
  }
}


static inline int64_t abs64(int64_t x) {
  return (((int64_t)((int32_t *)&x)[0])*((int64_t)((int32_t *)&x)[0]) + ((int64_t)
          ((int32_t *)&x)[1])*((int64_t)((int32_t *)&x)[1]));
}


int ru_sync_time(RU_t *ru,
                 int64_t *lev,
                 int64_t *avg) {
  LTE_DL_FRAME_PARMS *frame_parms = ru->frame_parms;
  RU_CALIBRATION *calibration = &ru->calibration;
  // perform a time domain correlation using the oversampled sync sequence
  int length =   LTE_NUMBER_OF_SUBFRAMES_PER_FRAME*frame_parms->samples_per_tti;

  // circular copy of beginning to end of rxdata buffer. Note: buffer should be big enough upon calling this function
  for (int ar=0; ar<ru->nb_rx; ar++)
    memcpy((void *)&ru->common.rxdata[ar][2*length],
           (void *)&ru->common.rxdata[ar][0],
           frame_parms->ofdm_symbol_size);

  int32_t maxlev0=0;
  int     maxpos0=0;
  int64_t avg0=0;
  int64_t result;
  int64_t dmrs_corr;
  int maxval=0;

  for (int i=0; i<2*(frame_parms->ofdm_symbol_size); i++) {
    maxval = max(maxval,ru->dmrssync[i]);
    maxval = max(maxval,-ru->dmrssync[i]);
  }

  if (ru->state == RU_CHECK_SYNC) {
    for (int i=0; i<2*(frame_parms->ofdm_symbol_size); i++) {
      maxval = max(maxval,calibration->drs_ch_estimates_time[0][i]);
      maxval = max(maxval,-calibration->drs_ch_estimates_time[0][i]);
    }
  }

  int shift = log2_approx(maxval);

  for (int n=0; n<length; n+=4) {
    dmrs_corr = 0;

    //calculate dot product of primary_synch0_time and rxdata[ar][n] (ar=0..nb_ant_rx) and store the sum in temp[n];
    for (int ar=0; ar<ru->nb_rx; ar++) {
      result  = dot_product64(ru->dmrssync,
                              (int16_t *) &ru->common.rxdata[ar][n],
                              frame_parms->ofdm_symbol_size,
                              shift);

      if (ru->state == RU_CHECK_SYNC) {
        result  = dot_product64((int16_t *) &calibration->drs_ch_estimates_time[ar],
                                (int16_t *) &ru->common.rxdata[ar][n],
                                frame_parms->ofdm_symbol_size,
                                shift);
      }

      dmrs_corr += abs64(result);
    }

    if (ru->dmrs_corr != NULL)
      ru->dmrs_corr[n] = dmrs_corr;

    // tmpi holds <synchi,rx0>+<synci,rx1>+...+<synchi,rx_{nbrx-1}>

    if (dmrs_corr>maxlev0) {
      maxlev0 = dmrs_corr;
      maxpos0 = n;
    }

    avg0 += dmrs_corr;
  }

  avg0/=(length/4);
  int dmrsoffset = frame_parms->samples_per_tti + (3*frame_parms->ofdm_symbol_size)+(3*frame_parms->nb_prefix_samples) + frame_parms->nb_prefix_samples0;

  if ((int64_t)maxlev0 > (10*avg0)) {
    *lev = maxlev0;
    *avg=avg0;
    return((length+maxpos0-dmrsoffset)%length);
  }

  return(-1);
}