233 lines
7.0 KiB
C
233 lines
7.0 KiB
C
/*******************************************************************************
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OpenAirInterface
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Copyright(c) 1999 - 2014 Eurecom
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OpenAirInterface is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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OpenAirInterface is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with OpenAirInterface.The full GNU General Public License is
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included in this distribution in the file called "COPYING". If not,
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see <http://www.gnu.org/licenses/>.
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Contact Information
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OpenAirInterface Admin: openair_admin@eurecom.fr
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OpenAirInterface Tech : openair_tech@eurecom.fr
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OpenAirInterface Dev : openair4g-devel@eurecom.fr
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Address : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE
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*******************************************************************************/
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#include "PHY/types.h"
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#include "PHY/defs.h"
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#include "PHY/extern.h"
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#include "MAC_INTERFACE/defs.h"
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#include "MAC_INTERFACE/extern.h"
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#define DEBUG_PHY
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// Adjust location synchronization point to account for drift
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// The adjustment is performed once per frame based on the
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// last channel estimate of the receiver
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void lte_adjust_synch(LTE_DL_FRAME_PARMS *frame_parms,
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PHY_VARS_UE *phy_vars_ue,
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unsigned char eNB_id,
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unsigned char clear,
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short coef)
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{
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static int max_pos_fil = 0;
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int temp = 0, i, aa, max_val = 0, max_pos = 0;
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int diff;
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short Re,Im,ncoef;
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ncoef = 32767 - coef;
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#ifdef DEBUG_PHY
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LOG_D(PHY,"frame %d: rx_offset (before) = %d\n",phy_vars_ue->frame_rx,phy_vars_ue->rx_offset);
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#endif //DEBUG_PHY
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// we only use channel estimates from tx antenna 0 here
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for (i = 0; i < frame_parms->nb_prefix_samples; i++) {
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temp = 0;
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for (aa=0;aa<frame_parms->nb_antennas_rx;aa++) {
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Re = ((int16_t*)phy_vars_ue->lte_ue_common_vars.dl_ch_estimates_time[eNB_id][aa])[(i<<2)];
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Im = ((int16_t*)phy_vars_ue->lte_ue_common_vars.dl_ch_estimates_time[eNB_id][aa])[1+(i<<2)];
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temp += (Re*Re/2) + (Im*Im/2);
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}
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if (temp > max_val) {
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max_pos = i;
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max_val = temp;
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}
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}
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// filter position to reduce jitter
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if (clear == 1)
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max_pos_fil = max_pos;
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else
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max_pos_fil = ((max_pos_fil * coef) + (max_pos * ncoef)) >> 15;
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diff = max_pos_fil - 2; //frame_parms->nb_prefix_samples/8;
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if ( diff > SYNCH_HYST )
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phy_vars_ue->rx_offset++;
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else if (diff < -SYNCH_HYST)
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phy_vars_ue->rx_offset--;
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if ( phy_vars_ue->rx_offset < 0 )
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phy_vars_ue->rx_offset += FRAME_LENGTH_COMPLEX_SAMPLES;
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if ( phy_vars_ue->rx_offset >= FRAME_LENGTH_COMPLEX_SAMPLES )
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phy_vars_ue->rx_offset -= FRAME_LENGTH_COMPLEX_SAMPLES;
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#ifdef DEBUG_PHY
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LOG_D(PHY,"frame %d: rx_offset (after) = %d : max_pos = %d,max_pos_fil = %d (peak %d)\n",
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phy_vars_ue->frame_rx,phy_vars_ue->rx_offset,max_pos,max_pos_fil,temp);
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#endif //DEBUG_PHY
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}
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int lte_est_timing_advance(LTE_DL_FRAME_PARMS *frame_parms,
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LTE_eNB_SRS *lte_eNb_srs,
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unsigned int *eNB_id,
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unsigned char clear,
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unsigned char number_of_cards,
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short coef)
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{
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static int max_pos_fil2 = 0;
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int temp, i, aa, max_pos = 0,ind;
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int max_val=0;
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short Re,Im,ncoef;
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#ifdef USER_MODE
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#ifdef DEBUG_PHY
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char fname[100],vname[100];
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#endif
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#endif
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ncoef = 32768 - coef;
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for (ind=0;ind<number_of_cards;ind++) {
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if (ind==0)
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max_val=0;
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for (aa=0;aa<frame_parms->nb_antennas_rx;aa++) {
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// do ifft of channel estimate
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fft((short*) <e_eNb_srs->srs_ch_estimates[ind][aa][0],
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(short*) lte_eNb_srs->srs_ch_estimates_time[ind][aa],
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frame_parms->twiddle_ifft,
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frame_parms->rev,
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frame_parms->log2_symbol_size,
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frame_parms->log2_symbol_size/2,
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0);
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#ifdef USER_MODE
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#ifdef DEBUG_PHY
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sprintf(fname,"srs_ch_estimates_time_%d%d.m",ind,aa);
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sprintf(vname,"srs_time_%d%d",ind,aa);
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write_output(fname,vname,lte_eNb_srs->srs_ch_estimates_time[ind][aa],frame_parms->ofdm_symbol_size*2,2,1);
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#endif
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#endif
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}
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// we only use channel estimates from tx antenna 0 here
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// remember we fixed the SRS to use only every second subcarriers
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for (i = 0; i < frame_parms->ofdm_symbol_size/2; i++) {
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temp = 0;
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for (aa=0;aa<frame_parms->nb_antennas_rx;aa++) {
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Re = ((int16_t*)lte_eNb_srs->srs_ch_estimates_time[ind][aa])[(i<<2)];
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Im = ((int16_t*)lte_eNb_srs->srs_ch_estimates_time[ind][aa])[1+(i<<2)];
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temp += (Re*Re/2) + (Im*Im/2);
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}
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if (temp > max_val) {
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max_pos = i;
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max_val = temp;
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*eNB_id = ind;
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}
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}
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}
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// filter position to reduce jitter
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if (clear == 1)
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max_pos_fil2 = max_pos;
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else
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max_pos_fil2 = ((max_pos_fil2 * coef) + (max_pos * ncoef)) >> 15;
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#ifdef DEBUG_PHY
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//LOG_D(PHY,"frame %d: max_pos = %d, max_pos_fil = %d\n",mac_xface->frame,max_pos,max_pos_fil2);
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#endif //DEBUG_PHY
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return(max_pos_fil2);
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}
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int lte_est_timing_advance_pusch(PHY_VARS_eNB* phy_vars_eNB,uint8_t UE_id,uint8_t sched_subframe)
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{
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static int first_run=1;
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static int max_pos_fil2=0;
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int temp, i, aa, max_pos=0, max_val=0;
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short Re,Im,coef=24576;
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short ncoef = 32768 - coef;
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LTE_DL_FRAME_PARMS *frame_parms = &phy_vars_eNB->lte_frame_parms;
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LTE_eNB_PUSCH *eNB_pusch_vars = phy_vars_eNB->lte_eNB_pusch_vars[UE_id];
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int32_t **ul_ch_estimates_time= eNB_pusch_vars->drs_ch_estimates_time[0];
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int subframe = phy_vars_eNB->proc[sched_subframe].subframe_rx;
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uint8_t harq_pid;
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uint8_t Ns = 1; //we take the estimate from the second slot
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uint8_t cyclic_shift = 0;//(frame_parms->pusch_config_common.ul_ReferenceSignalsPUSCH.cyclicShift +
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//phy_vars_eNB->ulsch_eNB[UE_id]->harq_processes[harq_pid]->n_DMRS2 +
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//frame_parms->pusch_config_common.ul_ReferenceSignalsPUSCH.nPRS[(subframe<<1)+Ns]) % 12;
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harq_pid = subframe2harq_pid(frame_parms,phy_vars_eNB->proc[sched_subframe].frame_rx,subframe);
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int sync_pos = (frame_parms->ofdm_symbol_size-cyclic_shift*frame_parms->ofdm_symbol_size/12)%(frame_parms->ofdm_symbol_size);
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for (i = 0; i < frame_parms->ofdm_symbol_size; i++) {
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temp = 0;
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for (aa=0;aa<frame_parms->nb_antennas_rx;aa++) {
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Re = ((int16_t*)ul_ch_estimates_time[aa])[(i<<2)];
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Im = ((int16_t*)ul_ch_estimates_time[aa])[1+(i<<2)];
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temp += (Re*Re/2) + (Im*Im/2);
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}
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if (temp > max_val) {
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max_pos = i;
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max_val = temp;
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}
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}
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// filter position to reduce jitter
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if (first_run == 1){
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first_run=0;
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max_pos_fil2 = max_pos;
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}
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else
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max_pos_fil2 = ((max_pos_fil2 * coef) + (max_pos * ncoef)) >> 15;
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#ifdef DEBUG_PHY
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LOG_I(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);
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#endif //DEBUG_PHY
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return(max_pos_fil2-sync_pos);
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}
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