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Added DL channel estimator algorithm options

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master
Xavier Arteaga 5 years ago committed by Xavier Arteaga
parent 355b2ed7e1
commit 9d0a3268e8
8 changed files with 107 additions and 38 deletions
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12
lib/examples/pdsch_ue.c
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@ -91,7 +91,7 @@ typedef struct {
uint32_t file_nof_ports;
uint32_t file_cell_id;
bool enable_cfo_ref;
bool average_subframe;
char* estimator_alg;
char* rf_dev;
char* rf_args;
uint32_t rf_nof_rx_ant;
@ -133,7 +133,7 @@ void args_default(prog_args_t* args)
args->rf_freq = -1.0;
args->rf_nof_rx_ant = 1;
args->enable_cfo_ref = false;
args->average_subframe = false;
args->estimator_alg = "interpolate";
args->enable_256qam = false;
#ifdef ENABLE_AGC_DEFAULT
args->rf_gain = -1.0;
@ -176,7 +176,7 @@ void usage(prog_args_t* args, char* prog)
printf("\t-l Force N_id_2 [Default best]\n");
printf("\t-C Disable CFO correction [Default %s]\n", args->disable_cfo ? "Disabled" : "Enabled");
printf("\t-F Enable RS-based CFO correction [Default %s]\n", !args->enable_cfo_ref ? "Disabled" : "Enabled");
printf("\t-R Average channel estimates on 1 ms [Default %s]\n", !args->average_subframe ? "Disabled" : "Enabled");
printf("\t-R Channel estimates algorithm (average, interpolate, wiener) [Default %s]\n", args->estimator_alg);
printf("\t-t Add time offset [Default %d]\n", args->time_offset);
printf("\t-T Set TDD special subframe configuration [Default %d]\n", args->tdd_special_sf);
printf("\t-G Set TDD uplink/downlink configuration [Default %d]\n", args->sf_config);
@ -242,7 +242,7 @@ void parse_args(prog_args_t* args, int argc, char** argv)
args->enable_cfo_ref = true;
break;
case 'R':
args->average_subframe = true;
args->estimator_alg = argv[optind];
break;
case 't':
args->time_offset = (uint32_t)strtol(argv[optind], NULL, 10);
@ -606,13 +606,13 @@ int main(int argc, char** argv)
srslte_chest_dl_cfg_t chest_pdsch_cfg = {};
chest_pdsch_cfg.cfo_estimate_enable = prog_args.enable_cfo_ref;
chest_pdsch_cfg.cfo_estimate_sf_mask = 1023;
chest_pdsch_cfg.interpolate_subframe = !prog_args.average_subframe;
chest_pdsch_cfg.estimator_alg = srslte_chest_dl_str2estimator_alg(prog_args.estimator_alg);
// Special configuration for MBSFN channel estimation
srslte_chest_dl_cfg_t chest_mbsfn_cfg = {};
chest_mbsfn_cfg.filter_type = SRSLTE_CHEST_FILTER_TRIANGLE;
chest_mbsfn_cfg.filter_coef[0] = 0.1;
chest_mbsfn_cfg.interpolate_subframe = true;
chest_mbsfn_cfg.estimator_alg = SRSLTE_ESTIMATOR_ALG_INTERPOLATE;
chest_mbsfn_cfg.noise_alg = SRSLTE_NOISE_ALG_PSS;
// Allocate softbuffer buffers

13
lib/include/srslte/phy/ch_estimation/chest_dl.h
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@ -67,12 +67,20 @@ typedef struct SRSLTE_API {
float sync_error;
} srslte_chest_dl_res_t;
// Noise estimation algorithm
typedef enum SRSLTE_API {
SRSLTE_NOISE_ALG_REFS = 0,
SRSLTE_NOISE_ALG_PSS,
SRSLTE_NOISE_ALG_EMPTY,
} srslte_chest_dl_noise_alg_t;
// Channel estimator algorithm
typedef enum SRSLTE_API {
SRSLTE_ESTIMATOR_ALG_AVERAGE = 0,
SRSLTE_ESTIMATOR_ALG_INTERPOLATE,
SRSLTE_ESTIMATOR_ALG_WIENER,
} srslte_chest_dl_estimator_alg_t;
typedef struct SRSLTE_API {
srslte_cell_t cell;
uint32_t nof_rx_antennas;
@ -114,12 +122,13 @@ typedef struct SRSLTE_API {
typedef struct SRSLTE_API {
srslte_chest_dl_estimator_alg_t estimator_alg;
srslte_chest_dl_noise_alg_t noise_alg;
srslte_chest_filter_t filter_type;
float filter_coef[2];
uint16_t mbsfn_area_id;
bool interpolate_subframe;
bool rsrp_neighbour;
bool cfo_estimate_enable;
uint32_t cfo_estimate_sf_mask;
@ -158,4 +167,6 @@ SRSLTE_API int srslte_chest_dl_estimate_cfg(srslte_chest_dl_t* q,
cf_t* input[SRSLTE_MAX_PORTS],
srslte_chest_dl_res_t* res);
SRSLTE_API srslte_chest_dl_estimator_alg_t srslte_chest_dl_str2estimator_alg(const char* str);
#endif // SRSLTE_CHEST_DL_H

64
lib/src/phy/ch_estimation/chest_dl.c
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@ -446,7 +446,7 @@ static void interpolate_pilots(srslte_chest_dl_t* q,
/* Interpolate in the frequency domain */
uint32_t freq_nsymbols = nsymbols;
if (!cfg->interpolate_subframe) {
if (cfg->estimator_alg == SRSLTE_ESTIMATOR_ALG_AVERAGE) {
freq_nsymbols = 1;
}
@ -470,7 +470,7 @@ static void interpolate_pilots(srslte_chest_dl_t* q,
(fidx_offset) ? 1 : 2);
}
} else {
if (!cfg->interpolate_subframe && nsymbols > 1) {
if (cfg->estimator_alg == SRSLTE_ESTIMATOR_ALG_AVERAGE && nsymbols > 1) {
fidx_offset = q->cell.id % 3;
srslte_interp_linear_offset(
&q->srslte_interp_lin_3, pilot_estimates, ce, fidx_offset, SRSLTE_NRE / 4 - fidx_offset);
@ -487,7 +487,7 @@ static void interpolate_pilots(srslte_chest_dl_t* q,
}
/* Now interpolate in the time domain between symbols */
if (sf->sf_type == SRSLTE_SF_NORM && (!cfg->interpolate_subframe || nsymbols < 3)) {
if (sf->sf_type == SRSLTE_SF_NORM && (cfg->estimator_alg == SRSLTE_ESTIMATOR_ALG_AVERAGE || nsymbols < 3)) {
// If we average per subframe, just copy the estimates in the time domain
for (uint32_t l = 1; l < 2 * SRSLTE_CP_NSYMB(q->cell.cp); l++) {
memcpy(&ce[l * SRSLTE_NRE * q->cell.nof_prb], ce, sizeof(cf_t) * SRSLTE_NRE * q->cell.nof_prb);
@ -547,7 +547,7 @@ static void average_pilots(srslte_chest_dl_t* q,
uint32_t nref = (sf->sf_type == SRSLTE_SF_MBSFN) ? 6 * q->cell.nof_prb : 2 * q->cell.nof_prb;
// Average in the time domain if enabled
if (!cfg->interpolate_subframe && nsymbols > 1) {
if (cfg->estimator_alg == SRSLTE_ESTIMATOR_ALG_AVERAGE && nsymbols > 1) {
cf_t* temp = output; // Use output as temporal buffer
if (srslte_refsignal_cs_fidx(q->cell, 0, port_id, 0) < 3) {
@ -645,24 +645,35 @@ static void chest_interpolate_noise_est(srslte_chest_dl_t* q,
q->noise_estimate[rxant_id][port_id] = estimate_noise_pilots(q, sf, port_id);
}
if (q->wiener_dl && ch_mode == SRSLTE_SF_NORM) {
if (q->wiener_dl && ch_mode == SRSLTE_SF_NORM && cfg->estimator_alg == SRSLTE_ESTIMATOR_ALG_WIENER) {
bool ready = q->wiener_dl->ready;
uint32_t nre = q->cell.nof_prb * SRSLTE_NRE;
uint32_t nref = q->cell.nof_prb * 2;
uint32_t shift = srslte_refsignal_cs_fidx(q->cell, 0, port_id, 0);
for (uint32_t m = 0, l = 0; m < 2 * SRSLTE_CP_NORM_NSYMB; m++) {
uint32_t k = srslte_refsignal_cs_nsymbol(l, q->cell.cp, 0);
srslte_wiener_dl_run(q->wiener_dl,
port_id,
rxant_id,
m,
shift,
&input[nref * l],
&ce[nre * m],
q->noise_estimate[rxant_id][port_id]);
uint32_t nsymb = srslte_refsignal_cs_nof_symbols(&q->csr_refs, sf, port_id);
float snr_lin = +INFINITY;
if (l == k) {
l++;
if (isnormal(q->noise_estimate[rxant_id][port_id]) && isnormal(q->rsrp[rxant_id][port_id])) {
snr_lin = q->rsrp[rxant_id][port_id] / q->noise_estimate[rxant_id][port_id] / 2;
}
for (uint32_t m = 0, l = 0; m < 2 * SRSLTE_CP_NORM_NSYMB + 4; m++) {
uint32_t ce_idx = 0;
if (m >= 4) {
ce_idx = (m - 4) * nre;
}
uint32_t k = srslte_refsignal_cs_nsymbol(l, q->cell.cp, port_id);
srslte_wiener_dl_run(
q->wiener_dl, port_id, rxant_id, m, shift, &q->pilot_estimates[nref * l], &ce[ce_idx], snr_lin);
if (m == k) {
l = (l + 1) % nsymb;
}
}
if (ready) {
return;
}
}
@ -686,7 +697,7 @@ static void chest_interpolate_noise_est(srslte_chest_dl_t* q,
break;
}
if (!cfg->interpolate_subframe && ch_mode == SRSLTE_SF_MBSFN) {
if (cfg->estimator_alg != SRSLTE_ESTIMATOR_ALG_INTERPOLATE && ch_mode == SRSLTE_SF_MBSFN) {
ERROR("Warning: Subframe interpolation must be enabled in MBSFN subframes\n");
}
@ -970,3 +981,20 @@ int srslte_chest_dl_estimate_cfg(srslte_chest_dl_t* q,
return SRSLTE_SUCCESS;
}
srslte_chest_dl_estimator_alg_t srslte_chest_dl_str2estimator_alg(const char* str)
{
srslte_chest_dl_estimator_alg_t ret = SRSLTE_ESTIMATOR_ALG_AVERAGE;
if (str) {
if (strcmp(str, "interpolate") == 0) {
ret = SRSLTE_ESTIMATOR_ALG_INTERPOLATE;
} else if (strcmp(str, "average") == 0) {
ret = SRSLTE_ESTIMATOR_ALG_AVERAGE;
} else if (strcmp(str, "wiener") == 0) {
ret = SRSLTE_ESTIMATOR_ALG_WIENER;
}
}
return ret;
}

2
lib/src/phy/phch/test/pmch_file_test.c
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@ -195,7 +195,7 @@ int main(int argc, char** argv)
// Special configuration for MBSFN channel estimation
ue_dl_cfg.chest_cfg.filter_type = SRSLTE_CHEST_FILTER_TRIANGLE;
ue_dl_cfg.chest_cfg.filter_coef[0] = 0.1;
ue_dl_cfg.chest_cfg.interpolate_subframe = true;
ue_dl_cfg.chest_cfg.estimator_alg = SRSLTE_ESTIMATOR_ALG_INTERPOLATE;
ue_dl_cfg.chest_cfg.noise_alg = SRSLTE_NOISE_ALG_PSS;
if ((ret = srslte_ue_dl_decode_fft_estimate(&ue_dl, &dl_sf, &ue_dl_cfg)) < 0) {

35
lib/src/phy/utils/mat.c
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@ -443,15 +443,23 @@ static inline void srslte_vec_sub_ccc_simd_inline(const cf_t* x, const cf_t* y,
static inline cf_t reciprocal(cf_t x)
{
cf_t y;
cf_t y = 0.0f;
float mod = __real__ x * __real__ x + __imag__ x * __imag__ x;
if (isnormal(mod)) {
__real__ y = (__real__ x) / mod;
__imag__ y = -(__imag__ x) / mod;
}
return y;
}
static inline float _cabs2(cf_t x)
{
return __real__ x * __real__ x + __imag__ x * __imag__ x;
}
void srslte_matrix_NxN_inv_run(srslte_matrix_NxN_inv_t* q, cf_t* in, cf_t* out)
{
if (q && in && out) {
@ -476,8 +484,29 @@ void srslte_matrix_NxN_inv_run(srslte_matrix_NxN_inv_t* q, cf_t* in, cf_t* out)
// 1) Forward elimination
for (int i = 0; i < N - 1; i++) {
tmp_src_ptr = &q->matrix[N * 2 * (N - 1 - i)];
cf_t b = tmp_src_ptr[N - 1 - i];
uint32_t row_i = N - i - 1;
uint32_t col_i = N - i - 1;
float max_v = 0.0f;
uint32_t max_i = 0;
// Find Row with highest value in the column to reduce
for (int j = 0; j < N - i; j++) {
float v = _cabs2(q->matrix[(j + 1) * 2 * N - 1 - i]);
if (v > max_v) {
max_i = j;
max_v = v;
}
}
// Swap rows
if (max_i != row_i) {
memcpy(q->row_buffer, &q->matrix[row_i * N * 2], sizeof(cf_t) * N * 2);
memcpy(&q->matrix[row_i * N * 2], &q->matrix[max_i * N * 2], sizeof(cf_t) * N * 2);
memcpy(&q->matrix[max_i * N * 2], q->row_buffer, sizeof(cf_t) * N * 2);
}
tmp_src_ptr = &q->matrix[N * 2 * row_i]; // Select row
cf_t b = tmp_src_ptr[col_i];
srslte_vec_sc_prod_ccc_simd_inline(tmp_src_ptr, reciprocal(b), tmp_src_ptr, 2 * N);
for (int j = 0; j < N - i - 1; j++) {

2
lib/test/phy/phy_dl_test.c
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@ -578,7 +578,7 @@ int main(int argc, char** argv)
ue_dl_cfg.chest_cfg.filter_type = SRSLTE_CHEST_FILTER_GAUSS;
ue_dl_cfg.chest_cfg.noise_alg = SRSLTE_NOISE_ALG_REFS;
ue_dl_cfg.chest_cfg.rsrp_neighbour = false;
ue_dl_cfg.chest_cfg.interpolate_subframe = false;
ue_dl_cfg.chest_cfg.estimator_alg = SRSLTE_ESTIMATOR_ALG_AVERAGE;
ue_dl_cfg.chest_cfg.cfo_estimate_enable = false;
ue_dl_cfg.chest_cfg.cfo_estimate_sf_mask = false;
ue_dl_cfg.chest_cfg.sync_error_enable = false;

6
srsue/src/phy/cc_worker.cc
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@ -87,7 +87,7 @@ cc_worker::cc_worker(uint32_t cc_idx_, uint32_t max_prb, srsue::phy_common* phy_
// Define MBSFN subframes channel estimation and save default one
chest_mbsfn_cfg.filter_type = SRSLTE_CHEST_FILTER_TRIANGLE;
chest_mbsfn_cfg.filter_coef[0] = 0.1;
chest_mbsfn_cfg.interpolate_subframe = true;
chest_mbsfn_cfg.estimator_alg = SRSLTE_ESTIMATOR_ALG_INTERPOLATE;
chest_mbsfn_cfg.noise_alg = SRSLTE_NOISE_ALG_PSS;
chest_default_cfg = ue_dl_cfg.chest_cfg;
@ -144,8 +144,8 @@ bool cc_worker::set_cell(srslte_cell_t cell_)
return false;
}
if (cell.frame_type == SRSLTE_TDD && !ue_dl_cfg.chest_cfg.interpolate_subframe) {
chest_default_cfg.interpolate_subframe = true;
if (cell.frame_type == SRSLTE_TDD && ue_dl_cfg.chest_cfg.estimator_alg != SRSLTE_ESTIMATOR_ALG_INTERPOLATE) {
chest_default_cfg.estimator_alg = SRSLTE_ESTIMATOR_ALG_INTERPOLATE;
log_h->console("Enabling subframe interpolation for TDD cells (recommended setting)\n");
}

3
srsue/src/phy/phy_common.cc
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@ -103,7 +103,8 @@ void phy_common::set_ue_dl_cfg(srslte_ue_dl_cfg_t* ue_dl_cfg)
chest_cfg->rsrp_neighbour = false;
chest_cfg->sync_error_enable = args->correct_sync_error;
chest_cfg->interpolate_subframe = args->interpolate_subframe_enabled;
chest_cfg->estimator_alg =
args->interpolate_subframe_enabled ? SRSLTE_ESTIMATOR_ALG_INTERPOLATE : SRSLTE_ESTIMATOR_ALG_AVERAGE;
chest_cfg->cfo_estimate_enable = args->cfo_ref_mask != 0;
chest_cfg->cfo_estimate_sf_mask = args->cfo_ref_mask;
}

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