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SRS channel interpolation improved for comb_size 2

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This commit is contained in:
rmagueta
2022-01-10 19:08:08 +00:00
parent af56207fdf
commit d14d36747d
3 changed files with 42 additions and 23 deletions
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openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c
+23 -23
View File
@@ -1107,7 +1107,6 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
uint16_t noise_real[frame_parms->nb_antennas_rx*nr_srs_info->sc_list_length];
uint16_t noise_imag[frame_parms->nb_antennas_rx*nr_srs_info->sc_list_length];
int16_t prev_ls_estimated[2];
int16_t ls_estimated[2];
for (int ant = 0; ant < frame_parms->nb_antennas_rx; ant++) {
@@ -1131,27 +1130,25 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
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->sc_list[sc_idx]] = ls_estimated[0] + (((int32_t)ls_estimated[1] << 16) & 0xFFFF0000);
if(sc_idx>0 && nr_srs_info->sc_list[sc_idx] > nr_srs_info->sc_list[sc_idx - 1]) {
ls_estimated[0] = (ls_estimated[0] + prev_ls_estimated[0])>>1;
ls_estimated[1] = (ls_estimated[1] + prev_ls_estimated[1])>>1;
}
prev_ls_estimated[0] = (int16_t)(((int32_t)generated_real*received_real + (int32_t)generated_imag*received_imag)>>nr_srs_info->srs_generated_signal_bits);
prev_ls_estimated[1] = (int16_t)(((int32_t)generated_real*received_imag - (int32_t)generated_imag*received_real)>>nr_srs_info->srs_generated_signal_bits);
// Channel interpolation
if(srs_pdu->comb_size == 0) {
if(sc_idx == 0) {
multadd_real_vector_complex_scalar(filt8_l0, ls_estimated, srs_estimated_channel16, 8);
} else if(nr_srs_info->sc_list[sc_idx] < nr_srs_info->sc_list[sc_idx - 1]) {
if(sc_idx == 0) { // First subcarrier case
// filt8_start is {12288,8192,4096,0,0,0,0,0}
multadd_real_vector_complex_scalar(filt8_start, ls_estimated, srs_estimated_channel16, 8);
} else if(nr_srs_info->sc_list[sc_idx] < nr_srs_info->sc_list[sc_idx - 1]) { // Start of OFDM symbol case
// filt8_start is {12288,8192,4096,0,0,0,0,0}
srs_estimated_channel16 = (int16_t *)&srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx + 2]] - 8;
multadd_real_vector_complex_scalar(filt8_l0, ls_estimated, srs_estimated_channel16, 8);
} else if((sc_idx < (nr_srs_info->sc_list_length - 1) && nr_srs_info->sc_list[sc_idx + 1] < nr_srs_info->sc_list[sc_idx]) || (sc_idx == (nr_srs_info->sc_list_length - 1))) {
multadd_real_vector_complex_scalar(filt8_m0, ls_estimated, srs_estimated_channel16, 8);
srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx] + 1] = srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx]];
} 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);
multadd_real_vector_complex_scalar(filt8_start, ls_estimated, srs_estimated_channel16, 8);
} else if((sc_idx < (nr_srs_info->sc_list_length - 1) && nr_srs_info->sc_list[sc_idx + 1] < nr_srs_info->sc_list[sc_idx])
|| (sc_idx == (nr_srs_info->sc_list_length - 1))) { // End of OFDM symbol or last subcarrier cases
// filt8_end is {4096,8192,12288,16384,0,0,0,0}
multadd_real_vector_complex_scalar(filt8_end, ls_estimated, srs_estimated_channel16, 8);
} else if(sc_idx%2 == 1) { // 1st middle case
// filt8_middle2 is {4096,8192,8192,8192,4096,0,0,0}
multadd_real_vector_complex_scalar(filt8_middle2, ls_estimated, srs_estimated_channel16, 8);
} else if(sc_idx%2 == 0) { // 2nd middle case
// filt8_middle4 is {0,0,4096,8192,8192,8192,4096,0}
multadd_real_vector_complex_scalar(filt8_middle4, ls_estimated, srs_estimated_channel16, 8);
srs_estimated_channel16 = (int16_t *)&srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx]];
}
} else {
@@ -1173,9 +1170,6 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
}
}
noise_real[ant*nr_srs_info->sc_list_length + sc_idx] = abs(prev_ls_estimated[0] - (int16_t)(srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx]] & 0xFFFF));
noise_imag[ant*nr_srs_info->sc_list_length + sc_idx] = abs(prev_ls_estimated[1] - (int16_t)((srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx]] >> 16) & 0xFFFF));
#ifdef SRS_DEBUG
uint64_t subcarrier_offset = frame_parms->first_carrier_offset + srs_pdu->bwp_start*12;
int subcarrier_log = nr_srs_info->sc_list[sc_idx]-subcarrier_offset;
@@ -1193,10 +1187,16 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
subcarrier_log,
generated_real, generated_imag,
received_real, received_imag,
prev_ls_estimated[0], prev_ls_estimated[1]);
ls_estimated[0], ls_estimated[1]);
#endif
}
// Compute noise
for(int sc_idx = 0; sc_idx < nr_srs_info->sc_list_length; sc_idx++) {
noise_real[ant*nr_srs_info->sc_list_length + sc_idx] = abs((int16_t)((srs_ls_estimated_channel[ant][nr_srs_info->sc_list[sc_idx]]-srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx]]) & 0xFFFF));
noise_imag[ant*nr_srs_info->sc_list_length + sc_idx] = abs((int16_t)(((srs_ls_estimated_channel[ant][nr_srs_info->sc_list[sc_idx]]-srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx]]) >> 16) & 0xFFFF));
}
// Convert to time domain
freq2time(gNB->frame_parms.ofdm_symbol_size,
(int16_t*) srs_estimated_channel_freq[ant],
openair1/PHY/NR_UE_ESTIMATION/filt16a_32.c
+13
View File
@@ -260,3 +260,16 @@ short filt8_avlip5[8] = {
short filt8_avlip6[8] = {
13653,15019,16384,16384,16384,16384,16384,16384};
// Comb size 2
short filt8_start[8] = {
12288,8192,4096,0,0,0,0,0};
short filt8_middle2[8] = {
4096,8192,8192,8192,4096,0,0,0};
short filt8_middle4[8] = {
0,0,4096,8192,8192,8192,4096,0};
short filt8_end[8] = {
4096,8192,12288,16384,0,0,0,0};
openair1/PHY/NR_UE_ESTIMATION/filt16a_32.h
+6
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@@ -182,4 +182,10 @@ extern short filt8_avlip4[8];
extern short filt8_avlip5[8];
extern short filt8_avlip6[8];
/*Comb size 2*/
extern short filt8_start[8];
extern short filt8_middle2[8];
extern short filt8_middle4[8];
extern short filt8_end[8];
#endif