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openairinterface5g/openair1/PHY/MODULATION/slot_fep.c
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/*******************************************************************************
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@eurecom.fr
Address : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE
*******************************************************************************/
#include "PHY/defs.h"
#include "MAC_INTERFACE/extern.h"
#include "defs.h"
//#define DEBUG_FEP
#define SOFFSET 0
void rescale(int16_t *input,int length) {
__m128i *input128 = (__m128i *)input;
int i;
for (i=0;i<length>>2;i++) {
input128[i] = _mm_srai_epi16(input128[i],4);
}
}
int slot_fep(PHY_VARS_UE *phy_vars_ue,
unsigned char l,
unsigned char Ns,
int sample_offset,
int no_prefix) {
LTE_DL_FRAME_PARMS *frame_parms = &phy_vars_ue->lte_frame_parms;
LTE_UE_COMMON *ue_common_vars = &phy_vars_ue->lte_ue_common_vars;
uint8_t eNB_id = 0;//ue_common_vars->eNb_id;
unsigned char aa;
unsigned char symbol = l+((7-frame_parms->Ncp)*(Ns&1)); ///symbol within sub-frame
unsigned int nb_prefix_samples = (no_prefix ? 0 : frame_parms->nb_prefix_samples);
unsigned int nb_prefix_samples0 = (no_prefix ? 0 : frame_parms->nb_prefix_samples0);
unsigned int subframe_offset;//,subframe_offset_F;
unsigned int slot_offset;
int i;
unsigned int frame_length_samples = frame_parms->samples_per_tti * 10;
unsigned int rx_offset;
void (*dft)(int16_t *,int16_t *, int);
int tmp_dft_in[256]; // This is for misalignment issues for 6 and 15 PRBs
switch (frame_parms->log2_symbol_size) {
case 7:
dft = dft128;
break;
case 8:
dft = dft256;
break;
case 9:
dft = dft512;
break;
case 10:
dft = dft1024;
break;
case 11:
dft = dft2048;
break;
default:
dft = dft512;
break;
}
if (no_prefix) {
subframe_offset = frame_parms->ofdm_symbol_size * frame_parms->symbols_per_tti * (Ns>>1);
slot_offset = frame_parms->ofdm_symbol_size * (frame_parms->symbols_per_tti>>1) * (Ns%2);
}
else {
subframe_offset = frame_parms->samples_per_tti * (Ns>>1);
slot_offset = (frame_parms->samples_per_tti>>1) * (Ns%2);
}
// subframe_offset_F = frame_parms->ofdm_symbol_size * frame_parms->symbols_per_tti * (Ns>>1);
if (l<0 || l>=7-frame_parms->Ncp) {
msg("slot_fep: l must be between 0 and %d\n",7-frame_parms->Ncp);
return(-1);
}
if (Ns<0 || Ns>=20) {
msg("slot_fep: Ns must be between 0 and 19\n");
return(-1);
}
for (aa=0;aa<frame_parms->nb_antennas_rx;aa++) {
memset(&ue_common_vars->rxdataF[aa][frame_parms->ofdm_symbol_size*symbol],0,frame_parms->ofdm_symbol_size*sizeof(int));
rx_offset = sample_offset + slot_offset + nb_prefix_samples0 + subframe_offset - SOFFSET;
// Align with 128 bit
rx_offset = rx_offset - rx_offset % 4;
#ifdef DEBUG_FEP
// if (phy_vars_ue->frame <100)
msg("slot_fep: frame %d: slot %d, symbol %d, nb_prefix_samples %d, nb_prefix_samples0 %d, slot_offset %d, subframe_offset %d, sample_offset %d,rx_offset %d\n", phy_vars_ue->frame_rx,Ns, symbol, nb_prefix_samples,nb_prefix_samples0,slot_offset,subframe_offset,sample_offset,rx_offset);
#endif
if (l==0) {
if (rx_offset > (frame_length_samples - frame_parms->ofdm_symbol_size))
memcpy((short *)&ue_common_vars->rxdata[aa][frame_length_samples],
(short *)&ue_common_vars->rxdata[aa][0],
frame_parms->ofdm_symbol_size*sizeof(int));
if ((rx_offset&3)!=0) { // if input to dft is not 128-bit aligned, issue for size 6 and 15 PRBs
memcpy((void *)tmp_dft_in,
(void *)&ue_common_vars->rxdata[aa][(rx_offset-nb_prefix_samples0) % frame_length_samples],
frame_parms->ofdm_symbol_size*sizeof(int));
#ifdef USRP
rescale((int16_t *)tmp_dft_in,
frame_parms->ofdm_symbol_size);
#endif
dft((int16_t *)tmp_dft_in,
(int16_t *)&ue_common_vars->rxdataF[aa][frame_parms->ofdm_symbol_size*symbol],1);
}
else {// use dft input from RX buffer directly
start_meas(&phy_vars_ue->rx_dft_stats);
#ifdef USRP
rescale((int16_t *)&ue_common_vars->rxdata[aa][(rx_offset-nb_prefix_samples0) % frame_length_samples],
frame_parms->ofdm_symbol_size+nb_prefix_samples0);
#endif
dft((int16_t *)&ue_common_vars->rxdata[aa][(rx_offset) % frame_length_samples],
(int16_t *)&ue_common_vars->rxdataF[aa][frame_parms->ofdm_symbol_size*symbol],1);
stop_meas(&phy_vars_ue->rx_dft_stats);
}
}
else {
rx_offset += (frame_parms->ofdm_symbol_size+nb_prefix_samples) +
(frame_parms->ofdm_symbol_size+nb_prefix_samples)*(l-1);
#ifdef DEBUG_FEP
// if (phy_vars_ue->frame <100)
msg("slot_fep: frame %d: slot %d, symbol %d, nb_prefix_samples %d, nb_prefix_samples0 %d, slot_offset %d, subframe_offset %d, sample_offset %d,rx_offset %d\n", phy_vars_ue->frame_rx,Ns, symbol, nb_prefix_samples,nb_prefix_samples0,slot_offset,subframe_offset,sample_offset,rx_offset);
#endif
if (rx_offset > (frame_length_samples - frame_parms->ofdm_symbol_size))
memcpy((void *)&ue_common_vars->rxdata[aa][frame_length_samples],
(void *)&ue_common_vars->rxdata[aa][0],
frame_parms->ofdm_symbol_size*sizeof(int));
start_meas(&phy_vars_ue->rx_dft_stats);
if ((rx_offset&3)!=0) { // if input to dft is not 128-bit aligned, issue for size 6 and 15 PRBs
memcpy((void *)tmp_dft_in,
(void *)&ue_common_vars->rxdata[aa][(rx_offset) % frame_length_samples],
frame_parms->ofdm_symbol_size*sizeof(int));
#ifdef USRP
rescale((int16_t *)tmp_dft_in,
frame_parms->ofdm_symbol_size);
#endif
dft((int16_t *)tmp_dft_in,
(int16_t *)&ue_common_vars->rxdataF[aa][frame_parms->ofdm_symbol_size*symbol],1);
}
else {// use dft input from RX buffer directly
#ifdef USRP
rescale((int16_t *)&ue_common_vars->rxdata[aa][(rx_offset-nb_prefix_samples) % frame_length_samples],
frame_parms->ofdm_symbol_size+nb_prefix_samples);
#endif
dft((int16_t *)&ue_common_vars->rxdata[aa][(rx_offset) % frame_length_samples],
(int16_t *)&ue_common_vars->rxdataF[aa][frame_parms->ofdm_symbol_size*symbol],1);
}
stop_meas(&phy_vars_ue->rx_dft_stats);
}
}
if (phy_vars_ue->perfect_ce == 0) {
if ((l==0) || (l==(4-frame_parms->Ncp))) {
for (aa=0;aa<frame_parms->nb_antennas_tx_eNB;aa++) {
#ifdef DEBUG_FEP
msg("Channel estimation eNB %d, aatx %d, slot %d, symbol %d\n",eNB_id,aa,Ns,l);
#endif
start_meas(&phy_vars_ue->dlsch_channel_estimation_stats);
lte_dl_channel_estimation(phy_vars_ue,eNB_id,0,
Ns,
aa,
l,
symbol);
stop_meas(&phy_vars_ue->dlsch_channel_estimation_stats);
for (i=0;i<phy_vars_ue->PHY_measurements.n_adj_cells;i++) {
lte_dl_channel_estimation(phy_vars_ue,eNB_id,i+1,
Ns,
aa,
l,
symbol);
}
}
// do frequency offset estimation here!
// use channel estimates from current symbol (=ch_t) and last symbol (ch_{t-1})
#ifdef DEBUG_FEP
msg("Frequency offset estimation\n");
#endif
if (l==(4-frame_parms->Ncp)) {
start_meas(&phy_vars_ue->dlsch_freq_offset_estimation_stats);
lte_est_freq_offset(ue_common_vars->dl_ch_estimates[0],
frame_parms,
l,
&ue_common_vars->freq_offset);
stop_meas(&phy_vars_ue->dlsch_freq_offset_estimation_stats);
}
}
}
#ifdef DEBUG_FEP
msg("slot_fep: done\n");
#endif
return(0);
}
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