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Compute the SNR per RB using the SRS

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This commit is contained in:
Roberto Louro Magueta
2022-05-09 15:54:20 +01:00
parent dcf4fd1db2
commit ab6d7afd09
5 changed files with 38 additions and 11 deletions
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openair1/PHY/INIT/nr_init.c
+2
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@@ -618,8 +618,10 @@ int phy_init_nr_gNB(PHY_VARS_gNB *gNB,
gNB->nr_srs_info[id] = (nr_srs_info_t *)malloc16_clear(sizeof(nr_srs_info_t));
gNB->nr_srs_info[id]->sc_list = (uint16_t *) malloc16_clear(6*fp->N_RB_UL*sizeof(uint16_t));
gNB->nr_srs_info[id]->srs_generated_signal = (int32_t*)malloc16_clear(fp->ofdm_symbol_size*MAX_NUM_NR_SRS_SYMBOLS*sizeof(int32_t));
gNB->nr_srs_info[id]->signal_power = (uint32_t*)malloc16_clear(sizeof(uint32_t));
gNB->nr_srs_info[id]->noise_power_per_rb = (uint32_t*)malloc16_clear(fp->N_RB_UL*sizeof(uint32_t));
gNB->nr_srs_info[id]->noise_power = (uint32_t*)malloc16_clear(sizeof(uint32_t));
gNB->nr_srs_info[id]->snr_per_rb = (int8_t*)malloc16_clear(fp->N_RB_UL*sizeof(int8_t));
gNB->nr_srs_info[id]->srs_received_signal = (int32_t **)malloc16(Prx*sizeof(int32_t*));
gNB->nr_srs_info[id]->srs_ls_estimated_channel = (int32_t **)malloc16(Prx*sizeof(int32_t*));
gNB->nr_srs_info[id]->srs_estimated_channel_freq = (int32_t **)malloc16(Prx*sizeof(int32_t*));
openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c
+28 -9
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@@ -1079,9 +1079,9 @@ void nr_pusch_ptrs_processing(PHY_VARS_gNB *gNB,
}//Antenna loop
}
uint32_t calc_power(uint16_t *x, uint32_t size) {
uint64_t sum_x = 0;
uint64_t sum_x2 = 0;
uint32_t calc_power(const int16_t *x, uint32_t size) {
int64_t sum_x = 0;
int64_t sum_x2 = 0;
for(int k = 0; k<size; k++) {
sum_x = sum_x + x[k];
sum_x2 = sum_x2 + x[k]*x[k];
@@ -1099,8 +1099,10 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
int32_t **srs_estimated_channel_freq,
int32_t **srs_estimated_channel_time,
int32_t **srs_estimated_channel_time_shifted,
uint32_t *signal_power,
uint32_t *noise_power_per_rb,
uint32_t *noise_power) {
uint32_t *noise_power,
int8_t *snr_per_rb) {
if(nr_srs_info->sc_list_length == 0) {
LOG_E(NR_PHY, "(%d.%d) nr_srs_info was not generated yet!\n", frame, slot);
@@ -1110,8 +1112,10 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
NR_DL_FRAME_PARMS *frame_parms = &gNB->frame_parms;
int32_t **srs_ls_estimated_channel = nr_srs_info->srs_ls_estimated_channel;
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 ch_real[frame_parms->nb_antennas_rx*nr_srs_info->sc_list_length];
int16_t ch_imag[frame_parms->nb_antennas_rx*nr_srs_info->sc_list_length];
int16_t noise_real[frame_parms->nb_antennas_rx*nr_srs_info->sc_list_length];
int16_t noise_imag[frame_parms->nb_antennas_rx*nr_srs_info->sc_list_length];
int16_t ls_estimated[2];
@@ -1199,8 +1203,10 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
// 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));
ch_real[ant*nr_srs_info->sc_list_length + sc_idx] = (int16_t)(srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx]] & 0xFFFF);
ch_imag[ant*nr_srs_info->sc_list_length + sc_idx] = (int16_t)((srs_estimated_channel_freq[ant][nr_srs_info->sc_list[sc_idx]] >> 16) & 0xFFFF);
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]] & 0xFFFF) - ch_real[ant*nr_srs_info->sc_list_length + sc_idx]);
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]] >> 16) & 0xFFFF) - ch_imag[ant*nr_srs_info->sc_list_length + sc_idx]);
}
// Convert to time domain
@@ -1217,8 +1223,20 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
(gNB->frame_parms.ofdm_symbol_size>>1)*sizeof(int32_t));
}
// Compute signal power
*signal_power = calc_power(ch_real,frame_parms->nb_antennas_rx*nr_srs_info->sc_list_length)
+ calc_power(ch_imag,frame_parms->nb_antennas_rx*nr_srs_info->sc_list_length);
#ifdef SRS_DEBUG
LOG_I(NR_PHY,"signal_power = %u\n", *signal_power);
#endif
// Compute noise power
uint8_t signal_power_bits = log2_approx(*signal_power);
uint8_t factor_bits = signal_power_bits < 32 ? 32 - signal_power_bits : 0; // 32 due to input of dB_fixed(uint32_t x)
int32_t factor_dB = dB_fixed(1<<factor_bits);
uint64_t subcarrier_offset = frame_parms->first_carrier_offset + srs_pdu->bwp_start*12;
uint8_t srs_symbols_per_rb = srs_pdu->comb_size == 0 ? 6 : 3;
uint8_t n_noise_estimates = frame_parms->nb_antennas_rx*srs_symbols_per_rb;
@@ -1247,6 +1265,7 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
if (count_estimates == n_noise_estimates) {
noise_power_per_rb[rb] = sum_re2/n_noise_estimates - (sum_re/n_noise_estimates)*(sum_re/n_noise_estimates) +
sum_im2/n_noise_estimates - (sum_im/n_noise_estimates)*(sum_im/n_noise_estimates);
snr_per_rb[rb] = dB_fixed((int32_t)((*signal_power<<factor_bits)/noise_power_per_rb[rb])) - factor_dB;
count_estimates = 0;
sum_re = 0;
sum_re2 = 0;
@@ -1254,7 +1273,7 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
sum_im2 = 0;
#ifdef SRS_DEBUG
LOG_I(NR_PHY,"noise_power_per_rb[%i] = %i\n", rb, noise_power_per_rb[rb]);
LOG_I(NR_PHY,"noise_power_per_rb[%i] = %i, snr_per_rb[%i] = %i dB\n", rb, noise_power_per_rb[rb], rb, snr_per_rb[rb]);
#endif
}
openair1/PHY/NR_ESTIMATION/nr_ul_estimation.h
+3 -1
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@@ -73,6 +73,8 @@ int nr_srs_channel_estimation(PHY_VARS_gNB *gNB,
int32_t **srs_estimated_channel_freq,
int32_t **srs_estimated_channel_time,
int32_t **srs_estimated_channel_time_shifted,
uint32_t *signal_power,
uint32_t *noise_power_per_rb,
uint32_t *noise_power);
uint32_t *noise_power,
int8_t *snr_per_rb);
#endif
openair1/PHY/defs_nr_common.h
+2
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@@ -244,8 +244,10 @@ typedef struct {
int32_t **srs_estimated_channel_freq;
int32_t **srs_estimated_channel_time;
int32_t **srs_estimated_channel_time_shifted;
uint32_t *signal_power;
uint32_t *noise_power_per_rb;
uint32_t *noise_power;
int8_t *snr_per_rb;
} nr_srs_info_t;
typedef struct NR_DL_FRAME_PARMS NR_DL_FRAME_PARMS;
openair1/SCHED_NR/phy_procedures_nr_gNB.c
+3 -1
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@@ -834,8 +834,10 @@ int phy_procedures_gNB_uespec_RX(PHY_VARS_gNB *gNB, int frame_rx, int slot_rx) {
gNB->nr_srs_info[i]->srs_estimated_channel_freq,
gNB->nr_srs_info[i]->srs_estimated_channel_time,
gNB->nr_srs_info[i]->srs_estimated_channel_time_shifted,
gNB->nr_srs_info[i]->signal_power,
gNB->nr_srs_info[i]->noise_power_per_rb,
gNB->nr_srs_info[i]->noise_power);
gNB->nr_srs_info[i]->noise_power,
gNB->nr_srs_info[i]->snr_per_rb);
T(T_GNB_PHY_UL_FREQ_CHANNEL_ESTIMATE, T_INT(0), T_INT(srs_pdu->rnti), T_INT(frame_rx), T_INT(0), T_INT(0),
T_BUFFER(gNB->nr_srs_info[i]->srs_estimated_channel_freq[0], gNB->frame_parms.ofdm_symbol_size*sizeof(int32_t)));