/*******************************************************************************
OpenAirInterface
Copyright(c) 1999 - 2014 Eurecom
OpenAirInterface is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OpenAirInterface is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with OpenAirInterface.The full GNU General Public License is
included in this distribution in the file called "COPYING". If not,
see <http://www.gnu.org/licenses/>.
Contact Information
OpenAirInterface Admin: openair_admin@eurecom.fr
OpenAirInterface Tech : openair_tech@eurecom.fr
OpenAirInterface Dev : openair4g-devel@lists.eurecom.fr
Address : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE
*******************************************************************************/
#include "PHY/types.h"
#include "PHY/defs.h"
#include "PHY/extern.h"
#define DEBUG_PHY
// Adjust location synchronization point to account for drift
// The adjustment is performed once per frame based on the
// last channel estimate of the receiver
void lte_adjust_synch(LTE_DL_FRAME_PARMS *frame_parms,
PHY_VARS_UE *phy_vars_ue,
unsigned char eNB_id,
unsigned char clear,
short coef)
{
static int max_pos_fil = 0;
int temp = 0, i, aa, max_val = 0, max_pos = 0;
int diff;
short Re,Im,ncoef;
ncoef = 32767 - coef;
#ifdef DEBUG_PHY
LOG_D(PHY,"frame %d, slot %d: rx_offset (before) = %d\n",phy_vars_ue->frame_rx,phy_vars_ue->slot_rx,phy_vars_ue->rx_offset);
#endif //DEBUG_PHY
// we only use channel estimates from tx antenna 0 here
for (i = 0; i < frame_parms->nb_prefix_samples; i++) {
temp = 0;
for (aa=0; aa<frame_parms->nb_antennas_rx; aa++) {
Re = ((int16_t*)phy_vars_ue->lte_ue_common_vars.dl_ch_estimates_time[eNB_id][aa])[(i<<2)];
Im = ((int16_t*)phy_vars_ue->lte_ue_common_vars.dl_ch_estimates_time[eNB_id][aa])[1+(i<<2)];
temp += (Re*Re/2) + (Im*Im/2);
}
if (temp > max_val) {
max_pos = i;
max_val = temp;
}
}
// filter position to reduce jitter
if (clear == 1)
max_pos_fil = max_pos;
else
max_pos_fil = ((max_pos_fil * coef) + (max_pos * ncoef)) >> 15;
diff = max_pos_fil - frame_parms->nb_prefix_samples/8;
if ( diff > SYNCH_HYST )
phy_vars_ue->rx_offset++;
else if (diff < -SYNCH_HYST)
phy_vars_ue->rx_offset--;
if ( phy_vars_ue->rx_offset < 0 )
phy_vars_ue->rx_offset += FRAME_LENGTH_COMPLEX_SAMPLES;
if ( phy_vars_ue->rx_offset >= FRAME_LENGTH_COMPLEX_SAMPLES )
phy_vars_ue->rx_offset -= FRAME_LENGTH_COMPLEX_SAMPLES;
#ifdef DEBUG_PHY
LOG_D(PHY,"frame %d: rx_offset (after) = %d : max_pos = %d,max_pos_fil = %d (peak %d)\n",
phy_vars_ue->frame_rx,phy_vars_ue->rx_offset,max_pos,max_pos_fil,temp);
#endif //DEBUG_PHY
}
int lte_est_timing_advance(LTE_DL_FRAME_PARMS *frame_parms,
LTE_eNB_SRS *lte_eNb_srs,
unsigned int *eNB_id,
unsigned char clear,
unsigned char number_of_cards,
short coef)
{
static int max_pos_fil2 = 0;
int temp, i, aa, max_pos = 0,ind;
int max_val=0;
short Re,Im,ncoef;
#ifdef USER_MODE
#ifdef DEBUG_PHY
char fname[100],vname[100];
#endif
#endif
ncoef = 32768 - coef;
for (ind=0; ind<number_of_cards; ind++) {
if (ind==0)
max_val=0;
for (aa=0; aa<frame_parms->nb_antennas_rx; aa++) {
// do ifft of channel estimate
switch(frame_parms->N_RB_DL) {
case 6:
dft128((int16_t*) <e_eNb_srs->srs_ch_estimates[ind][aa][0],
(int16_t*) lte_eNb_srs->srs_ch_estimates_time[ind][aa],
1);
break;
case 25:
dft512((int16_t*) <e_eNb_srs->srs_ch_estimates[ind][aa][0],
(int16_t*) lte_eNb_srs->srs_ch_estimates_time[ind][aa],
1);
break;
case 50:
dft1024((int16_t*) <e_eNb_srs->srs_ch_estimates[ind][aa][0],
(int16_t*) lte_eNb_srs->srs_ch_estimates_time[ind][aa],
1);
break;
case 100:
dft2048((int16_t*) <e_eNb_srs->srs_ch_estimates[ind][aa][0],
(int16_t*) lte_eNb_srs->srs_ch_estimates_time[ind][aa],
1);
break;
}
#ifdef USER_MODE
#ifdef DEBUG_PHY
sprintf(fname,"srs_ch_estimates_time_%d%d.m",ind,aa);
sprintf(vname,"srs_time_%d%d",ind,aa);
write_output(fname,vname,lte_eNb_srs->srs_ch_estimates_time[ind][aa],frame_parms->ofdm_symbol_size*2,2,1);
#endif
#endif
}
// we only use channel estimates from tx antenna 0 here
// remember we fixed the SRS to use only every second subcarriers
for (i = 0; i < frame_parms->ofdm_symbol_size/2; i++) {
temp = 0;
for (aa=0; aa<frame_parms->nb_antennas_rx; aa++) {
Re = ((int16_t*)lte_eNb_srs->srs_ch_estimates_time[ind][aa])[(i<<1)];
Im = ((int16_t*)lte_eNb_srs->srs_ch_estimates_time[ind][aa])[1+(i<<1)];
temp += (Re*Re/2) + (Im*Im/2);
}
if (temp > max_val) {
max_pos = i;
max_val = temp;
*eNB_id = ind;
}
}
}
// filter position to reduce jitter
if (clear == 1)
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\n",mac_xface->frame,max_pos,max_pos_fil2);
#endif //DEBUG_PHY
return(max_pos_fil2);
}
int lte_est_timing_advance_pusch(PHY_VARS_eNB* phy_vars_eNB,uint8_t UE_id,uint8_t sched_subframe)
{
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;
LTE_DL_FRAME_PARMS *frame_parms = &phy_vars_eNB->lte_frame_parms;
LTE_eNB_PUSCH *eNB_pusch_vars = phy_vars_eNB->lte_eNB_pusch_vars[UE_id];
int32_t **ul_ch_estimates_time= eNB_pusch_vars->drs_ch_estimates_time[0];
uint8_t cyclic_shift = 0;
int sync_pos = (frame_parms->ofdm_symbol_size-cyclic_shift*frame_parms->ofdm_symbol_size/12)%(frame_parms->ofdm_symbol_size);
for (i = 0; i < frame_parms->ofdm_symbol_size; i++) {
temp = 0;
for (aa=0; aa<frame_parms->nb_antennas_rx; aa++) {
Re = ((int16_t*)ul_ch_estimates_time[aa])[(i<<1)];
Im = ((int16_t*)ul_ch_estimates_time[aa])[1+(i<<1)];
temp += (Re*Re/2) + (Im*Im/2);
}
if (temp > max_val) {
max_pos = i;
max_val = temp;
}
}
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",phy_vars_eNB->proc[sched_subframe].frame_rx,max_pos,max_pos_fil2,sync_pos);
#endif //DEBUG_PHY
return(max_pos_fil2-sync_pos);
}