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Improved CFO loop. Fixed issue with sinusoid tolerance

This commit is contained in:
Ismael Gomez 2017-12-16 12:46:29 +01:00
parent 56f95ec8be
commit 9355cd5732
16 changed files with 81 additions and 51 deletions
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2
lib/examples/pdsch_ue.c
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@ -546,7 +546,7 @@ int main(int argc, char **argv) {
exit(-1);
}
srslte_chest_dl_cfo_estimate_enable(&ue_dl.chest, prog_args.enable_cfo_ref, 0xff, 0.005);
srslte_chest_dl_cfo_estimate_enable(&ue_dl.chest, prog_args.enable_cfo_ref, 1023);
srslte_chest_dl_average_subframe(&ue_dl.chest, prog_args.average_subframe);
/* Configure downlink receiver for the SI-RNTI since will be the only one we'll use */

4
lib/include/srslte/phy/ch_estimation/chest_dl.h
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@ -87,7 +87,6 @@ typedef struct {
bool cfo_estimate_enable;
uint32_t cfo_estimate_sf_mask;
float cfo_ema;
/* Use PSS for noise estimation in LS linear interpolation mode */
cf_t pss_signal[SRSLTE_PSS_LEN];
@ -153,8 +152,7 @@ SRSLTE_API int srslte_chest_dl_estimate_port(srslte_chest_dl_t *q,
SRSLTE_API void srslte_chest_dl_cfo_estimate_enable(srslte_chest_dl_t *q,
bool enable,
uint32_t mask,
float ema);
uint32_t mask);
SRSLTE_API void srslte_chest_dl_average_subframe(srslte_chest_dl_t *q,
bool enable);

3
lib/include/srslte/phy/sync/cfo.h
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@ -40,9 +40,6 @@
#include "srslte/config.h"
#include "srslte/phy/utils/cexptab.h"
/** If the frequency is changed more than the tolerance, a new table is generated */
#define SRSLTE_CFO_TOLERANCE 0.00001
#define SRSLTE_CFO_CEXPTAB_SIZE 4096
typedef struct SRSLTE_API {

1
lib/include/srslte/phy/sync/sync.h
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@ -102,6 +102,7 @@ typedef struct SRSLTE_API {
bool cfo_i_initiated;
float cfo_cp_mean;
float cfo_pss;
float cfo_pss_mean;
int cfo_i_value;

10
lib/include/srslte/phy/ue/ue_sync.h
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@ -62,6 +62,16 @@
#include "srslte/phy/io/filesource.h"
#define DEFAULT_CFO_BW_PSS 0.05
#define DEFAULT_CFO_PSS_MIN 400 // typical bias of PSS estimation.
#define DEFAULT_CFO_BW_REF 0.01
#define DEFAULT_CFO_REF_MIN 0 // typical bias of REF estimation
#define DEFAULT_CFO_REF_MAX DEFAULT_CFO_PSS_MIN // Maximum detection offset of REF based estimation
#define DEFAULT_PSS_STABLE_TIMEOUT 20 // Time after which the PSS is considered to be stable and we accept REF-CFO
#define DEFAULT_CFO_EMA_TRACK 0.05
typedef enum SRSLTE_API { SF_FIND, SF_TRACK} srslte_ue_sync_state_t;
//#define MEASURE_EXEC_TIME

13
lib/src/phy/ch_estimation/chest_dl.c
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@ -467,7 +467,11 @@ float chest_estimate_cfo(srslte_chest_dl_t *q)
}
void chest_interpolate_noise_est(srslte_chest_dl_t *q, cf_t *input, cf_t *ce, uint32_t sf_idx, uint32_t port_id, uint32_t rxant_id, srslte_sf_t ch_mode){
if (ce != NULL) {
if (q->cfo_estimate_enable && ((1<<sf_idx) & q->cfo_estimate_sf_mask)) {
q->cfo = chest_estimate_cfo(q);
}
if (ce != NULL) {
/* Smooth estimates (if applicable) and interpolate */
if (q->smooth_filter_len == 0 || (q->smooth_filter_len == 3 && q->smooth_filter[0] == 0)) {
interpolate_pilots(q, q->pilot_estimates, ce, port_id, ch_mode);
@ -490,10 +494,6 @@ void chest_interpolate_noise_est(srslte_chest_dl_t *q, cf_t *input, cf_t *ce, ui
}
}
if (q->cfo_estimate_enable && ((1<<sf_idx) & q->cfo_estimate_sf_mask)) {
q->cfo = SRSLTE_VEC_EMA(chest_estimate_cfo(q), q->cfo, q->cfo_ema);
}
/* Compute RSRP for the channel estimates in this port */
uint32_t npilots = SRSLTE_REFSIGNAL_NUM_SF(q->cell.nof_prb, port_id);
float energy = cabsf(srslte_vec_acc_cc(q->pilot_estimates, npilots)/npilots);
@ -581,9 +581,8 @@ void srslte_chest_dl_average_subframe(srslte_chest_dl_t *q, bool enable)
q->average_subframe = enable;
}
void srslte_chest_dl_cfo_estimate_enable(srslte_chest_dl_t *q, bool enable, uint32_t mask, float ema)
void srslte_chest_dl_cfo_estimate_enable(srslte_chest_dl_t *q, bool enable, uint32_t mask)
{
q->cfo_ema = ema;
q->cfo_estimate_enable = enable;
q->cfo_estimate_sf_mask = mask;
}

2
lib/src/phy/sync/cfo.c
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@ -45,7 +45,7 @@ int srslte_cfo_init(srslte_cfo_t *h, uint32_t nsamples) {
if (!h->cur_cexp) {
goto clean;
}
h->tol = SRSLTE_CFO_TOLERANCE;
h->tol = 0;
h->last_freq = 0;
h->nsamples = nsamples;
h->max_samples = nsamples;

1
lib/src/phy/sync/pss.c
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@ -120,6 +120,7 @@ int srslte_pss_init_fft_offset_decim(srslte_pss_t *q,
buffer_size = fft_size + frame_size + 1;
q->filter_pss_enable = false;
q->chest_on_filter = false;
if(q->decimate > 1) {
int filter_order = 3;

12
lib/src/phy/sync/sync.c
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@ -475,7 +475,7 @@ srslte_pss_t* srslte_sync_get_cur_pss_obj(srslte_sync_t *q)
static float cfo_cp_estimate(srslte_sync_t *q, const cf_t *input)
{
uint32_t cp_offset = 0;
cp_offset = srslte_cp_synch(&q->cp_synch, input, q->max_offset, 7, SRSLTE_CP_LEN_NORM(1,q->fft_size));
cp_offset = srslte_cp_synch(&q->cp_synch, input, q->max_offset, 1, SRSLTE_CP_LEN_NORM(1,q->fft_size));
cf_t cp_corr_max = srslte_cp_synch_corr_output(&q->cp_synch, cp_offset);
float cfo = -carg(cp_corr_max) / M_PI / 2;
return cfo;
@ -612,16 +612,16 @@ srslte_sync_find_ret_t srslte_sync_find(srslte_sync_t *q, const cf_t *input, uin
}
// PSS-based CFO estimation
float cfo_pss = srslte_pss_cfo_compute(&q->pss, pss_ptr);
q->cfo_pss = srslte_pss_cfo_compute(&q->pss, pss_ptr);
if (!q->cfo_pss_is_set) {
q->cfo_pss_mean = cfo_pss;
q->cfo_pss_mean = q->cfo_pss;
q->cfo_pss_is_set = true;
} else if (15000*fabsf(cfo_pss) < MAX_CFO_PSS_OFFSET) {
q->cfo_pss_mean = SRSLTE_VEC_EMA(cfo_pss, q->cfo_pss_mean, q->cfo_ema_alpha);
} else if (15000*fabsf(q->cfo_pss) < MAX_CFO_PSS_OFFSET) {
q->cfo_pss_mean = SRSLTE_VEC_EMA(q->cfo_pss, q->cfo_pss_mean, q->cfo_ema_alpha);
}
INFO("PSS-CFO: filter=%s, estimated=%f, mean=%f\n",
q->pss_filtering_enabled?"yes":"no", cfo_pss, q->cfo_pss_mean);
q->pss_filtering_enabled?"yes":"no", q->cfo_pss, q->cfo_pss_mean);
}

37
lib/src/phy/ue/ue_sync.c
View File

@ -29,7 +29,7 @@
#include <strings.h>
#include <assert.h>
#include <unistd.h>
#include <srslte/srslte.h>
#include "srslte/srslte.h"
#include "srslte/phy/ue/ue_sync.h"
@ -47,14 +47,6 @@
#define DEFAULT_SAMPLE_OFFSET_CORRECT_PERIOD 0
#define DEFAULT_SFO_EMA_COEFF 0.1
#define DEFAULT_CFO_BW 0.2
#define DEFAULT_CFO_PSS_MIN 500 // typical bias of PSS estimation.
#define DEFAULT_CFO_REF_MIN 0 // typical bias of REF estimation
#define DEFAULT_CFO_REF_MAX 500 // Maximum detection offset of REF based estimation
#define DEFAULT_PSS_STABLE_TIMEOUT 100 // Time after which the PSS is considered to be stable and we accept REF-CFO
#define DEFAULT_CFO_EMA_TRACK 0.1
cf_t dummy_buffer0[15*2048/2];
cf_t dummy_buffer1[15*2048/2];
@ -226,8 +218,8 @@ int srslte_ue_sync_init_multi_decim(srslte_ue_sync_t *q,
q->cfo_ref_max = DEFAULT_CFO_REF_MAX;
q->cfo_ref_min = DEFAULT_CFO_REF_MIN;
q->cfo_pss_min = DEFAULT_CFO_PSS_MIN;
q->cfo_loop_bw_pss = DEFAULT_CFO_BW;
q->cfo_loop_bw_ref = DEFAULT_CFO_BW;
q->cfo_loop_bw_pss = DEFAULT_CFO_BW_PSS;
q->cfo_loop_bw_ref = DEFAULT_CFO_BW_REF;
q->cfo_correct_enable = true;
q->pss_stable_cnt = 0;
@ -679,6 +671,8 @@ int srslte_ue_sync_zerocopy(srslte_ue_sync_t *q, cf_t *input_buffer) {
return srslte_ue_sync_zerocopy_multi(q, _input_buffer);
}
int track_time, find_time;
/* Returns 1 if the subframe is synchronized in time, 0 otherwise */
int srslte_ue_sync_zerocopy_multi(srslte_ue_sync_t *q, cf_t *input_buffer[SRSLTE_MAX_PORTS]) {
int ret = SRSLTE_ERROR_INVALID_INPUTS;
@ -723,10 +717,16 @@ int srslte_ue_sync_zerocopy_multi(srslte_ue_sync_t *q, cf_t *input_buffer[SRSLTE
fprintf(stderr, "Error receiving samples\n");
return SRSLTE_ERROR;
}
int n;
struct timeval t[3];
switch (q->state) {
case SF_FIND:
switch(srslte_sync_find(&q->sfind, input_buffer[0], 0, &q->peak_idx)) {
gettimeofday(&t[1], NULL);
n = srslte_sync_find(&q->sfind, input_buffer[0], 0, &q->peak_idx);
gettimeofday(&t[2], NULL);
get_time_interval(t);
find_time = t[0].tv_usec;
switch(n) {
case SRSLTE_SYNC_ERROR:
ret = SRSLTE_ERROR;
fprintf(stderr, "Error finding correlation peak (%d)\n", ret);
@ -781,9 +781,14 @@ int srslte_ue_sync_zerocopy_multi(srslte_ue_sync_t *q, cf_t *input_buffer[SRSLTE
* In tracking phase, the subframe carrying the PSS is always the last one of the frame
*/
track_idx = 0;
switch(srslte_sync_find(&q->strack, input_buffer[0],
q->frame_len - q->sf_len/2 - q->fft_size - q->strack.max_offset/2,
&track_idx))
gettimeofday(&t[1], NULL);
int n = srslte_sync_find(&q->strack, input_buffer[0],
q->frame_len - q->sf_len/2 - q->fft_size - q->strack.max_offset/2,
&track_idx);
gettimeofday(&t[2], NULL);
get_time_interval(t);
track_time = t[0].tv_usec;
switch(n)
{
case SRSLTE_SYNC_ERROR:
fprintf(stderr, "Error tracking correlation peak\n");

2
lib/src/phy/ue/ue_ul.c
View File

@ -38,7 +38,7 @@
#define MAX_SFLEN SRSLTE_SF_LEN(srslte_symbol_sz(max_prb))
#define DEFAULT_CFO_TOL 0.0 // Hz
#define DEFAULT_CFO_TOL 1.0 // Hz
int srslte_ue_ul_init(srslte_ue_ul_t *q,
cf_t *out_buffer,

2
srsue/hdr/phy/phch_worker.h
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@ -67,6 +67,8 @@ public:
int read_pdsch_d(cf_t *pdsch_d);
void start_plot();
float get_ref_cfo();
private:
/* Inherited from thread_pool::worker. Function called every subframe to run the DL/UL processing */
void work_imp();

17
srsue/src/main.cc
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@ -37,6 +37,7 @@
#include <boost/program_options/parsers.hpp>
#include "ue.h"
#include "srslte/srslte.h"
#include "metrics_stdout.h"
#include "metrics_csv.h"
#include "srslte/common/metrics_hub.h"
@ -201,40 +202,42 @@ void parse_args(all_args_t *args, int argc, char *argv[]) {
"Enables integer CFO estimation and correction.")
("expert.cfo_correct_tol_hz",
bpo::value<float>(&args->expert.phy.cfo_correct_tol_hz)->default_value(0.0),
bpo::value<float>(&args->expert.phy.cfo_correct_tol_hz)->default_value(1.0),
"Tolerance (in Hz) for digital CFO compensation (needs to be low if average_subframe_enabled=true.")
("expert.cfo_pss_ema",
bpo::value<float>(&args->expert.phy.cfo_pss_ema)->default_value(0.01),
bpo::value<float>(&args->expert.phy.cfo_pss_ema)->default_value(DEFAULT_CFO_EMA_TRACK),
"CFO Exponential Moving Average coefficient for PSS estimation during TRACK.")
/* REF EMA is currently not used
("expert.cfo_ref_ema",
bpo::value<float>(&args->expert.phy.cfo_ref_ema)->default_value(0.01),
"CFO Exponential Moving Average coefficient for RS estimation after PSS acquisition")
*/
("expert.cfo_ref_mask",
bpo::value<uint32_t>(&args->expert.phy.cfo_ref_mask)->default_value(1023),
"Bitmask for subframes on which to run RS estimation (set to 0 to disable, default all sf)")
("expert.cfo_loop_bw_pss",
bpo::value<float>(&args->expert.phy.cfo_loop_bw_pss)->default_value(0.05),
bpo::value<float>(&args->expert.phy.cfo_loop_bw_pss)->default_value(DEFAULT_CFO_BW_PSS),
"CFO feedback loop bandwidth for samples from PSS")
("expert.cfo_loop_bw_ref",
bpo::value<float>(&args->expert.phy.cfo_loop_bw_ref)->default_value(0.01),
bpo::value<float>(&args->expert.phy.cfo_loop_bw_ref)->default_value(DEFAULT_CFO_BW_REF),
"CFO feedback loop bandwidth for samples from RS")
("expert.cfo_loop_pss_tol",
bpo::value<float>(&args->expert.phy.cfo_loop_pss_tol)->default_value(300),
bpo::value<float>(&args->expert.phy.cfo_loop_pss_tol)->default_value(DEFAULT_CFO_PSS_MIN),
"Tolerance (in Hz) of the PSS estimation method. Below this value, PSS estimation does not feeds back the loop"
"and RS estimations are used instead (when available)")
("expert.cfo_loop_ref_min",
bpo::value<float>(&args->expert.phy.cfo_loop_ref_min)->default_value(0),
bpo::value<float>(&args->expert.phy.cfo_loop_ref_min)->default_value(DEFAULT_CFO_REF_MIN),
"Tolerance (in Hz) of the RS estimation method. Below this value, RS estimation does not feeds back the loop")
("expert.cfo_loop_pss_conv",
bpo::value<uint32_t>(&args->expert.phy.cfo_loop_pss_conv)->default_value(20),
bpo::value<uint32_t>(&args->expert.phy.cfo_loop_pss_conv)->default_value(DEFAULT_PSS_STABLE_TIMEOUT),
"After the PSS estimation is below cfo_loop_pss_tol for cfo_loop_pss_timeout times consecutively, RS adjustments are allowed.")
("expert.sic_pss_enabled",

10
srsue/src/phy/phch_recv.cc
View File

@ -539,6 +539,7 @@ double phch_recv::set_rx_gain(double gain) {
void phch_recv::run_thread()
{
phch_worker *worker = NULL;
phch_worker *last_worker = NULL;
cf_t *buffer[SRSLTE_MAX_PORTS] = {NULL};
uint32_t sf_idx = 0;
phy_state = IDLE;
@ -637,6 +638,15 @@ void phch_recv::run_thread()
switch(srslte_ue_sync_zerocopy_multi(&ue_sync, buffer)) {
case 1:
if (last_worker) {
Warning("SF: cfo=%7.1f Hz, ref=%f Hz, pss=%f Hz\n",
srslte_ue_sync_get_cfo(&ue_sync),
15000*last_worker->get_ref_cfo(),
15000*ue_sync.strack.cfo_pss_mean);
}
last_worker = worker;
Debug("SYNC: Worker %d synchronized\n", worker->get_id());
metrics.sfo = srslte_ue_sync_get_sfo(&ue_sync);

7
srsue/src/phy/phch_worker.cc
View File

@ -132,7 +132,7 @@ bool phch_worker::init(uint32_t max_prb, srslte::log *log_h, chest_feedback_itf
}
srslte_chest_dl_average_subframe(&ue_dl.chest, phy->args->average_subframe_enabled);
srslte_chest_dl_cfo_estimate_enable(&ue_dl.chest, phy->args->cfo_ref_mask!=0, phy->args->cfo_ref_mask, phy->args->cfo_ref_ema);
srslte_chest_dl_cfo_estimate_enable(&ue_dl.chest, phy->args->cfo_ref_mask!=0, phy->args->cfo_ref_mask);
srslte_ue_ul_set_normalization(&ue_ul, true);
srslte_ue_ul_set_cfo_enable(&ue_ul, true);
@ -195,6 +195,11 @@ void phch_worker::set_crnti(uint16_t rnti)
rnti_is_set = true;
}
float phch_worker::get_ref_cfo()
{
return srslte_chest_dl_get_cfo(&ue_dl.chest);
}
void phch_worker::work_imp()
{
if (!cell_initiated) {

9
srsue/ue.conf.example
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@ -202,15 +202,14 @@ enable = false
# CFO related values
#cfo_integer_enabled = false
#cfo_correct_tol_hz = 0
#cfo_pss_ema = 0.1
#cfo_ref_ema = 0.01
#cfo_correct_tol_hz = 1.0
#cfo_pss_ema = 0.05
#cfo_ref_mask = 1023
#cfo_loop_bw_pss = 0.05
#cfo_loop_bw_ref = 0.01
#cfo_loop_pss_tol = 300
#cfo_loop_pss_tol = 400
#cfo_loop_ref_min = 0
#cfo_loop_pss_conv = 50
#cfo_loop_pss_conv = 20
#####################################################################
# Manual RF calibration