Commit dbba6c65 authored by rmagueta's avatar rmagueta

Perform channel interpolation for SRS at gNB

parent 3a983dbf
......@@ -274,10 +274,10 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
ch,
ul_ch,
8);
//for (int i= 0; i<16; i++)
//printf("ul_ch addr %p %d\n", ul_ch+i, *(ul_ch+i));
pil += 2;
re_offset = (re_offset+2) % gNB->frame_parms.ofdm_symbol_size;
rxF = (int16_t *)&rxdataF[aarx][(soffset+symbol_offset+nushift+re_offset)];
......@@ -1112,11 +1112,15 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
int32_t **srs_ls_estimated_channel = nr_srs_info->srs_ls_estimated_channel;
uint64_t subcarrier_offset = frame_parms->first_carrier_offset + srs_pdu->bwp_start*12;
int16_t ls_estimated[2];
for (int ant = 0; ant < frame_parms->nb_antennas_rx; ant++) {
memset(srs_ls_estimated_channel[ant], 0, frame_parms->samples_per_frame*sizeof(int32_t));
memset(srs_estimated_channel[ant], 0, frame_parms->samples_per_frame*sizeof(int32_t));
int16_t *srs_estimated_channel16 = (int16_t *)&srs_estimated_channel[ant][nr_srs_info->subcarrier_idx[0] + subcarrier_offset];
for(int sc_idx = 0; sc_idx < nr_srs_info->n_symbs; sc_idx++) {
int16_t generated_real = srs_generated_signal[nr_srs_info->subcarrier_idx[sc_idx] + subcarrier_offset]&0xFFFF;
......@@ -1127,10 +1131,19 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
// We know that nr_srs_info->srs_generated_signal_bits bits are enough to represent the generated_real and generated_imag.
// So we only need a nr_srs_info->srs_generated_signal_bits shift to ensure that the result fits into 16 bits.
int16_t ls_estimated_real = (int16_t)(((int32_t)generated_real*received_real + (int32_t)generated_imag*received_imag)>>nr_srs_info->srs_generated_signal_bits);
int16_t ls_estimated_imag = (int16_t)(((int32_t)generated_real*received_imag - (int32_t)generated_imag*received_real)>>nr_srs_info->srs_generated_signal_bits);
ls_estimated[0] = (int16_t)(((int32_t)generated_real*received_real + (int32_t)generated_imag*received_imag)>>nr_srs_info->srs_generated_signal_bits);
ls_estimated[1] = (int16_t)(((int32_t)generated_real*received_imag - (int32_t)generated_imag*received_real)>>nr_srs_info->srs_generated_signal_bits);
srs_ls_estimated_channel[ant][nr_srs_info->subcarrier_idx[sc_idx] + subcarrier_offset] = ls_estimated[0] + (((int32_t)ls_estimated[1]<<16)&0xFFFF0000);
srs_ls_estimated_channel[ant][nr_srs_info->subcarrier_idx[sc_idx] + subcarrier_offset] = ls_estimated_real + (((int32_t)ls_estimated_imag<<16)&0xFFFF0000);
if(sc_idx == 0) {
multadd_real_vector_complex_scalar(filt8_l0, ls_estimated, srs_estimated_channel16, 8);
} else if(sc_idx%2 == 1) {
multadd_real_vector_complex_scalar(filt8_m0, ls_estimated, srs_estimated_channel16, 8);
} else if(sc_idx%2 == 0) {
multadd_real_vector_complex_scalar(filt8_mm0, ls_estimated, srs_estimated_channel16, 8);
srs_estimated_channel16+=8;
}
#ifdef SRS_DEBUG
if(sc_idx == 0) {
......@@ -1149,5 +1162,25 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
}
}
#ifdef SRS_DEBUG
for (int ant = 0; ant < frame_parms->nb_antennas_rx; ant++) {
for(int sc = 0; sc <= nr_srs_info->subcarrier_idx[nr_srs_info->n_symbs-1]; sc++) {
if(sc == 0) {
LOG_I(NR_PHY,"__________________ Rx antenna %i ___________________\n", ant);
}
if(sc%12 == 0) {
LOG_I(NR_PHY,":::::::::::::::::::::::: %i ::::::::::::::::::::::::\n", sc/12);
LOG_I(NR_PHY,"\t __lsRe__________lsIm__|____intRe_______intIm_\n");
}
LOG_I(NR_PHY,"(%4i) %6i\t%6i | %6i\t%6i\n",
sc,
(int16_t)(srs_ls_estimated_channel[ant][sc+subcarrier_offset]&0xFFFF),
(int16_t)((srs_ls_estimated_channel[ant][sc+subcarrier_offset]>>16)&0xFFFF),
(int16_t)(srs_estimated_channel[ant][sc+subcarrier_offset]&0xFFFF),
(int16_t)((srs_estimated_channel[ant][sc+subcarrier_offset]>>16)&0xFFFF));
}
}
#endif
return 0;
}
\ No newline at end of file
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