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SRSUE: refactored sync.cc and clean up

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master
Xavier Arteaga 5 years ago committed by Xavier Arteaga
parent 2d8bd0692a
commit ac0e347d94
7 changed files with 928 additions and 701 deletions
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64
srsue/hdr/phy/search.h
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@ -0,0 +1,64 @@
/*
* Copyright 2013-2020 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsLTE is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#ifndef SRSUE_SEARCH_H
#define SRSUE_SEARCH_H
#include "srslte/interfaces/ue_interfaces.h"
#include "srslte/radio/radio.h"
#include "srslte/srslte.h"
namespace srsue {
class search_callback
{
public:
virtual int radio_recv_fnc(srslte::rf_buffer_t&, uint32_t nsamples, srslte_timestamp_t* rx_time) = 0;
virtual void set_ue_sync_opts(srslte_ue_sync_t* q, float cfo) = 0;
virtual srslte::radio_interface_phy* get_radio() = 0;
virtual void set_rx_gain(float gain) = 0;
};
// Class to run cell search
class search
{
public:
typedef enum { CELL_NOT_FOUND, CELL_FOUND, ERROR, TIMEOUT } ret_code;
~search();
void init(srslte::rf_buffer_t& buffer_, srslte::log* log_h, uint32_t nof_rx_channels, search_callback* parent);
void reset();
float get_last_cfo();
void set_agc_enable(bool enable);
ret_code run(srslte_cell_t* cell, std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload);
private:
search_callback* p = nullptr;
srslte::log* log_h = nullptr;
srslte::rf_buffer_t buffer = {};
srslte_ue_cellsearch_t cs = {};
srslte_ue_mib_sync_t ue_mib_sync = {};
int force_N_id_2 = 0;
};
}; // namespace srsue
#endif // SRSUE_SEARCH_H

71
srsue/hdr/phy/sfn_sync.h
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/*
* Copyright 2013-2020 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsLTE is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#ifndef SRSUE_SFN_SYNC_H
#define SRSUE_SFN_SYNC_H
#include "srslte/interfaces/ue_interfaces.h"
#include "srslte/radio/radio.h"
#include "srslte/srslte.h"
namespace srsue {
// Class to synchronize system frame number
class sfn_sync
{
public:
typedef enum { IDLE, SFN_FOUND, SFX0_FOUND, SFN_NOFOUND, ERROR } ret_code;
sfn_sync() = default;
~sfn_sync();
void init(srslte_ue_sync_t* ue_sync,
const phy_args_t* phy_args_,
srslte::rf_buffer_t& buffer,
uint32_t buffer_max_samples_,
srslte::log* log_h,
uint32_t nof_subframes = SFN_SYNC_NOF_SUBFRAMES);
void reset();
bool set_cell(srslte_cell_t cell);
ret_code run_subframe(srslte_cell_t* cell,
uint32_t* tti_cnt,
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload,
bool sfidx_only = false);
ret_code decode_mib(srslte_cell_t* cell,
uint32_t* tti_cnt,
srslte::rf_buffer_t* ext_buffer,
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload,
bool sfidx_only = false);
private:
const static int SFN_SYNC_NOF_SUBFRAMES = 100;
const phy_args_t* phy_args = nullptr;
uint32_t cnt = 0;
uint32_t timeout = 0;
srslte::log* log_h = nullptr;
srslte_ue_sync_t* ue_sync = nullptr;
srslte::rf_buffer_t mib_buffer = {};
uint32_t buffer_max_samples = 0;
srslte_ue_mib_t ue_mib = {};
};
}; // namespace srsue
#endif // SRSUE_SFN_SYNC_H

257
srsue/hdr/phy/sync.h
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@ -26,29 +26,31 @@
#include <map>
#include <mutex>
#include <pthread.h>
#include <srslte/phy/channel/channel.h>
#include "phy_common.h"
#include "prach.h"
#include "scell/intra_measure.h"
#include "search.h"
#include "sf_worker.h"
#include "sfn_sync.h"
#include "srslte/common/log.h"
#include "srslte/common/thread_pool.h"
#include "srslte/common/threads.h"
#include "srslte/common/tti_sync_cv.h"
#include "srslte/interfaces/radio_interfaces.h"
#include "srslte/interfaces/ue_interfaces.h"
#include "srslte/phy/channel/channel.h"
#include "srslte/srslte.h"
#include <srsue/hdr/phy/scell/intra_measure.h>
#include "sync_state.h"
namespace srsue {
typedef _Complex float cf_t;
class sync : public srslte::thread, public chest_feedback_itf
class sync : public srslte::thread, public chest_feedback_itf, public search_callback
{
public:
sync() : thread("SYNC"), sf_buffer(sync_nof_rx_subframes){};
sync() : thread("SYNC"), sf_buffer(sync_nof_rx_subframes), dummy_buffer(sync_nof_rx_subframes){};
~sync();
void init(srslte::radio_interface_phy* radio_,
@ -86,78 +88,62 @@ public:
void force_freq(float dl_freq, float ul_freq);
// Other functions
void set_rx_gain(float gain);
int radio_recv_fnc(srslte::rf_buffer_t&, uint32_t nsamples, srslte_timestamp_t* rx_time);
void set_rx_gain(float gain) override;
int radio_recv_fnc(srslte::rf_buffer_t&, uint32_t nsamples, srslte_timestamp_t* rx_time) override;
private:
// Class to run cell search
class search
{
public:
typedef enum { CELL_NOT_FOUND, CELL_FOUND, ERROR, TIMEOUT } ret_code;
~search();
void init(srslte::rf_buffer_t& buffer_, srslte::log* log_h, uint32_t nof_rx_channels, sync* parent);
void reset();
float get_last_cfo();
void set_agc_enable(bool enable);
ret_code run(srslte_cell_t* cell, std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload);
srslte::radio_interface_phy* get_radio() override { return radio_h; }
private:
sync* p = nullptr;
srslte::log* log_h = nullptr;
srslte::rf_buffer_t buffer = {};
srslte_ue_cellsearch_t cs = {};
srslte_ue_mib_sync_t ue_mib_sync = {};
int force_N_id_2 = 0;
};
// Class to synchronize system frame number
class sfn_sync
{
public:
typedef enum { IDLE, SFN_FOUND, SFX0_FOUND, SFN_NOFOUND, ERROR } ret_code;
sfn_sync() = default;
~sfn_sync();
void init(srslte_ue_sync_t* ue_sync,
const phy_args_t* phy_args_,
srslte::rf_buffer_t& buffer,
uint32_t buffer_max_samples_,
srslte::log* log_h,
uint32_t nof_subframes = SFN_SYNC_NOF_SUBFRAMES);
void reset();
bool set_cell(srslte_cell_t cell);
ret_code run_subframe(srslte_cell_t* cell,
uint32_t* tti_cnt,
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload,
bool sfidx_only = false);
ret_code decode_mib(srslte_cell_t* cell,
uint32_t* tti_cnt,
srslte::rf_buffer_t* ext_buffer,
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload,
bool sfidx_only = false);
void radio_error();
void set_ue_sync_opts(srslte_ue_sync_t* q, float cfo) override;
private:
const static int SFN_SYNC_NOF_SUBFRAMES = 100;
/**
* Search for a cell in the current frequency and go to IDLE.
* The function search_p.run() will not return until the search finishes
*/
void run_cell_search_state();
const phy_args_t* phy_args = nullptr;
uint32_t cnt = 0;
uint32_t timeout = 0;
srslte::log* log_h = nullptr;
srslte_ue_sync_t* ue_sync = nullptr;
srslte::rf_buffer_t mib_buffer = {};
uint32_t buffer_max_samples = 0;
srslte_ue_mib_t ue_mib = {};
};
/**
* SFN synchronization using MIB. run_subframe() receives and processes 1 subframe
* and returns
*/
void run_sfn_sync_state();
/* TODO: Intra-freq measurements can be improved by capturing 200 ms length signal and run cell search +
* measurements offline using sync object and finding multiple cells for each N_id_2
/**
* Cell camping state. Calls the PHCH workers to process subframes and maintains cell synchronization
*/
void run_camping_state();
void reset();
void radio_error();
void set_ue_sync_opts(srslte_ue_sync_t* q, float cfo);
/**
* Receives and discards received samples. Does not maintain synchronization
*/
void run_idle_state();
/**
* MAIN THREAD
*
* The main thread process the SYNC state machine. Every state except IDLE must have exclusive access to
* all variables. If any change of cell configuration must be done, the thread must be in IDLE.
*
* On each state except campling, 1 function is called and the thread jumps to the next state based on the output.
*
* It has 3 states: Cell search, SFN synchronization, initial measurement and camping.
* - CELL_SEARCH: Initial Cell id and MIB acquisition. Uses 1.92 MHz sampling rate
* - CELL_SYNC: Full sampling rate, uses MIB to obtain SFN. When SFN is obtained, moves to CELL_CAMP
* - CELL_CAMP: Cell camping state. Calls the PHCH workers to process subframes and maintains cell
* synchronization.
* - IDLE: Receives and discards received samples. Does not maintain synchronization.
*
*/
void run_thread() final;
/**
* Helper method, executed when the UE is camping and in-sync
* @param worker Selected worker for the current TTI
* @param sync_buffer Sub-frame buffer for the current TTI
*/
void run_camping_in_sync_state(sf_worker* worker, srslte::rf_buffer_t& sync_buffer);
float get_tx_cfo();
void set_sampling_rate();
@ -174,8 +160,6 @@ private:
sfn_sync sfn_p;
std::vector<std::unique_ptr<scell::intra_measure> > intra_freq_meas;
uint32_t current_sflen = 0;
// Pointers to other classes
stack_interface_phy_lte* stack = nullptr;
srslte::log* log_h = nullptr;
@ -186,12 +170,19 @@ private:
prach* prach_buffer = nullptr;
srslte::channel_ptr channel_emulator = nullptr;
// PRACH state
uint32_t prach_nof_sf = 0;
uint32_t prach_sf_cnt = 0;
cf_t* prach_ptr = nullptr;
float prach_power = 0;
// Object for synchronization of the primary cell
srslte_ue_sync_t ue_sync = {};
// Buffer for primary and secondary cell samples
const static uint32_t sync_nof_rx_subframes = 5;
srslte::rf_buffer_t sf_buffer = {};
srslte::rf_buffer_t dummy_buffer;
// Sync metrics
sync_metrics_t metrics = {};
@ -200,133 +191,6 @@ private:
uint32_t out_of_sync_cnt = 0;
uint32_t in_sync_cnt = 0;
// State machine for SYNC thread
class sync_state
{
public:
typedef enum {
IDLE = 0,
CELL_SEARCH,
SFN_SYNC,
CAMPING,
} state_t;
/* Run_state is called by the main thread at the start of each loop. It updates the state
* and returns the current state
*/
state_t run_state()
{
std::lock_guard<std::mutex> lock(inside);
cur_state = next_state;
if (state_setting) {
state_setting = false;
state_running = true;
}
cvar.notify_all();
return cur_state;
}
// Called by the main thread at the end of each state to indicate it has finished.
void state_exit(bool exit_ok = true)
{
std::lock_guard<std::mutex> lock(inside);
if (cur_state == SFN_SYNC && exit_ok == true) {
next_state = CAMPING;
} else {
next_state = IDLE;
}
state_running = false;
cvar.notify_all();
}
void force_sfn_sync()
{
std::lock_guard<std::mutex> lock(inside);
next_state = SFN_SYNC;
}
/* Functions to be called from outside the STM thread to instruct the STM to switch state.
* The functions change the state and wait until it has changed it.
*
* These functions are mutexed and only 1 can be called at a time
*/
void go_idle()
{
std::lock_guard<std::mutex> lock(outside);
go_state(IDLE);
}
void run_cell_search()
{
std::lock_guard<std::mutex> lock(outside);
go_state(CELL_SEARCH);
wait_state_run();
wait_state_next();
}
void run_sfn_sync()
{
std::lock_guard<std::mutex> lock(outside);
go_state(SFN_SYNC);
wait_state_run();
wait_state_next();
}
/* Helpers below this */
bool is_idle() { return cur_state == IDLE; }
bool is_camping() { return cur_state == CAMPING; }
const char* to_string()
{
switch (cur_state) {
case IDLE:
return "IDLE";
case CELL_SEARCH:
return "SEARCH";
case SFN_SYNC:
return "SYNC";
case CAMPING:
return "CAMPING";
default:
return "UNKNOWN";
}
}
sync_state() = default;
private:
void go_state(state_t s)
{
std::unique_lock<std::mutex> ul(inside);
next_state = s;
state_setting = true;
while (state_setting) {
cvar.wait(ul);
}
}
/* Waits until there is a call to set_state() and then run_state(). Returns when run_state() returns */
void wait_state_run()
{
std::unique_lock<std::mutex> ul(inside);
while (state_running) {
cvar.wait(ul);
}
}
void wait_state_next()
{
std::unique_lock<std::mutex> ul(inside);
while (cur_state != next_state) {
cvar.wait(ul);
}
}
bool state_running = false;
bool state_setting = false;
state_t cur_state = IDLE;
state_t next_state = IDLE;
std::mutex inside;
std::mutex outside;
std::condition_variable cvar;
};
std::mutex rrc_mutex;
sync_state phy_state;
@ -339,6 +203,7 @@ private:
// This is the primary cell
srslte_cell_t cell = {};
bool force_camping_sfn_sync = false;
uint32_t tti = 0;
srslte_timestamp_t tti_ts = {};
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN> mib = {};

155
srsue/hdr/phy/sync_state.h
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/*
* Copyright 2013-2020 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsLTE is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#ifndef SRSUE_SYNC_STATE_H
#define SRSUE_SYNC_STATE_H
namespace srsue {
class sync_state
{
public:
typedef enum {
IDLE = 0,
CELL_SEARCH,
SFN_SYNC,
CAMPING,
} state_t;
/* Run_state is called by the main thread at the start of each loop. It updates the state
* and returns the current state
*/
state_t run_state()
{
std::lock_guard<std::mutex> lock(inside);
cur_state = next_state;
if (state_setting) {
state_setting = false;
state_running = true;
}
cvar.notify_all();
return cur_state;
}
// Called by the main thread at the end of each state to indicate it has finished.
void state_exit(bool exit_ok = true)
{
std::lock_guard<std::mutex> lock(inside);
if (cur_state == SFN_SYNC && exit_ok == true) {
next_state = CAMPING;
} else {
next_state = IDLE;
}
state_running = false;
cvar.notify_all();
}
void force_sfn_sync()
{
std::lock_guard<std::mutex> lock(inside);
next_state = SFN_SYNC;
}
/* Functions to be called from outside the STM thread to instruct the STM to switch state.
* The functions change the state and wait until it has changed it.
*
* These functions are mutexed and only 1 can be called at a time
*/
void go_idle()
{
std::lock_guard<std::mutex> lock(outside);
go_state(IDLE);
}
void run_cell_search()
{
std::lock_guard<std::mutex> lock(outside);
go_state(CELL_SEARCH);
wait_state_run();
wait_state_next();
}
void run_sfn_sync()
{
std::lock_guard<std::mutex> lock(outside);
go_state(SFN_SYNC);
wait_state_run();
wait_state_next();
}
/* Helpers below this */
bool is_idle() { return cur_state == IDLE; }
bool is_camping() { return cur_state == CAMPING; }
const char* to_string()
{
switch (cur_state) {
case IDLE:
return "IDLE";
case CELL_SEARCH:
return "SEARCH";
case SFN_SYNC:
return "SYNC";
case CAMPING:
return "CAMPING";
default:
return "UNKNOWN";
}
}
sync_state() = default;
private:
void go_state(state_t s)
{
std::unique_lock<std::mutex> ul(inside);
next_state = s;
state_setting = true;
while (state_setting) {
cvar.wait(ul);
}
}
/* Waits until there is a call to set_state() and then run_state(). Returns when run_state() returns */
void wait_state_run()
{
std::unique_lock<std::mutex> ul(inside);
while (state_running) {
cvar.wait(ul);
}
}
void wait_state_next()
{
std::unique_lock<std::mutex> ul(inside);
while (cur_state != next_state) {
cvar.wait(ul);
}
}
bool state_running = false;
bool state_setting = false;
state_t cur_state = IDLE;
state_t next_state = IDLE;
std::mutex inside;
std::mutex outside;
std::condition_variable cvar;
};
}; // namespace srsue
#endif // SRSUE_SYNC_STATE_H

200
srsue/src/phy/search.cc
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@ -0,0 +1,200 @@
/*
* Copyright 2013-2020 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsLTE is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#include "srsue/hdr/phy/search.h"
#define Error(fmt, ...) \
if (SRSLTE_DEBUG_ENABLED) \
log_h->error(fmt, ##__VA_ARGS__)
#define Warning(fmt, ...) \
if (SRSLTE_DEBUG_ENABLED) \
log_h->warning(fmt, ##__VA_ARGS__)
#define Info(fmt, ...) \
if (SRSLTE_DEBUG_ENABLED) \
log_h->info(fmt, ##__VA_ARGS__)
#define Debug(fmt, ...) \
if (SRSLTE_DEBUG_ENABLED) \
log_h->debug(fmt, ##__VA_ARGS__)
namespace srsue {
static int
radio_recv_callback(void* obj, cf_t* data[SRSLTE_MAX_CHANNELS], uint32_t nsamples, srslte_timestamp_t* rx_time)
{
srslte::rf_buffer_t x(data);
return ((search_callback*)obj)->radio_recv_fnc(x, nsamples, rx_time);
}
static SRSLTE_AGC_CALLBACK(callback_set_rx_gain)
{
((search_callback*)h)->set_rx_gain(gain_db);
}
search::~search()
{
srslte_ue_mib_sync_free(&ue_mib_sync);
srslte_ue_cellsearch_free(&cs);
}
void search::init(srslte::rf_buffer_t& buffer_, srslte::log* log_h_, uint32_t nof_rx_channels, search_callback* parent)
{
log_h = log_h_;
p = parent;
buffer = buffer_;
if (srslte_ue_cellsearch_init_multi(&cs, 8, radio_recv_callback, nof_rx_channels, parent)) {
Error("SYNC: Initiating UE cell search\n");
}
srslte_ue_cellsearch_set_nof_valid_frames(&cs, 4);
if (srslte_ue_mib_sync_init_multi(&ue_mib_sync, radio_recv_callback, nof_rx_channels, parent)) {
Error("SYNC: Initiating UE MIB synchronization\n");
}
// Set options defined in expert section
p->set_ue_sync_opts(&cs.ue_sync, 0);
force_N_id_2 = -1;
}
void search::reset()
{
srslte_ue_sync_reset(&ue_mib_sync.ue_sync);
}
float search::get_last_cfo()
{
return srslte_ue_sync_get_cfo(&ue_mib_sync.ue_sync);
}
void search::set_agc_enable(bool enable)
{
if (enable) {
srslte_rf_info_t* rf_info = p->get_radio()->get_info();
srslte_ue_sync_start_agc(&ue_mib_sync.ue_sync,
callback_set_rx_gain,
rf_info->min_rx_gain,
rf_info->max_rx_gain,
p->get_radio()->get_rx_gain());
} else {
ERROR("Error stop AGC not implemented\n");
}
}
search::ret_code search::run(srslte_cell_t* cell_, std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload)
{
srslte_cell_t new_cell = {};
srslte_ue_cellsearch_result_t found_cells[3];
bzero(found_cells, 3 * sizeof(srslte_ue_cellsearch_result_t));
/* Find a cell in the given N_id_2 or go through the 3 of them to find the strongest */
uint32_t max_peak_cell = 0;
int ret = SRSLTE_ERROR;
Info("SYNC: Searching for cell...\n");
log_h->console(".");
if (force_N_id_2 >= 0 && force_N_id_2 < 3) {
ret = srslte_ue_cellsearch_scan_N_id_2(&cs, force_N_id_2, &found_cells[force_N_id_2]);
max_peak_cell = force_N_id_2;
} else {
ret = srslte_ue_cellsearch_scan(&cs, found_cells, &max_peak_cell);
}
if (ret < 0) {
Error("SYNC: Error decoding MIB: Error searching PSS\n");
return ERROR;
} else if (ret == 0) {
Info("SYNC: Could not find any cell in this frequency\n");
return CELL_NOT_FOUND;
}
// Save result
new_cell.id = found_cells[max_peak_cell].cell_id;
new_cell.cp = found_cells[max_peak_cell].cp;
new_cell.frame_type = found_cells[max_peak_cell].frame_type;
float cfo = found_cells[max_peak_cell].cfo;
log_h->console("\n");
Info("SYNC: PSS/SSS detected: Mode=%s, PCI=%d, CFO=%.1f KHz, CP=%s\n",
new_cell.frame_type ? "TDD" : "FDD",
new_cell.id,
cfo / 1000,
srslte_cp_string(new_cell.cp));
if (srslte_ue_mib_sync_set_cell(&ue_mib_sync, new_cell)) {
Error("SYNC: Setting UE MIB cell\n");
return ERROR;
}
// Set options defined in expert section
p->set_ue_sync_opts(&ue_mib_sync.ue_sync, cfo);
srslte_ue_sync_reset(&ue_mib_sync.ue_sync);
/* Find and decode MIB */
int sfn_offset;
ret = srslte_ue_mib_sync_decode(&ue_mib_sync, 40, bch_payload.data(), &new_cell.nof_ports, &sfn_offset);
if (ret == 1) {
srslte_pbch_mib_unpack(bch_payload.data(), &new_cell, NULL);
// pack MIB and store inplace for PCAP dump
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN / 8> mib_packed;
srslte_bit_pack_vector(bch_payload.data(), mib_packed.data(), SRSLTE_BCH_PAYLOAD_LEN);
std::copy(std::begin(mib_packed), std::end(mib_packed), std::begin(bch_payload));
fprintf(stdout,
"Found Cell: Mode=%s, PCI=%d, PRB=%d, Ports=%d, CFO=%.1f KHz\n",
new_cell.frame_type ? "TDD" : "FDD",
new_cell.id,
new_cell.nof_prb,
new_cell.nof_ports,
cfo / 1000);
Info("SYNC: MIB Decoded: Mode=%s, PCI=%d, PRB=%d, Ports=%d, CFO=%.1f KHz\n",
new_cell.frame_type ? "TDD" : "FDD",
new_cell.id,
new_cell.nof_prb,
new_cell.nof_ports,
cfo / 1000);
if (!srslte_cell_isvalid(&new_cell)) {
Error("SYNC: Detected invalid cell.\n");
return CELL_NOT_FOUND;
}
// Save cell pointer
if (cell_) {
*cell_ = new_cell;
}
return CELL_FOUND;
} else if (ret == 0) {
Warning("SYNC: Found PSS but could not decode PBCH\n");
return CELL_NOT_FOUND;
} else {
Error("SYNC: Receiving MIB\n");
return ERROR;
}
}
}; // namespace srsue

167
srsue/src/phy/sfn_sync.cc
Unescape Escape View File

@ -0,0 +1,167 @@
/*
* Copyright 2013-2020 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsLTE is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#include "srsue/hdr/phy/sfn_sync.h"
#define Error(fmt, ...) \
if (SRSLTE_DEBUG_ENABLED) \
log_h->error(fmt, ##__VA_ARGS__)
#define Warning(fmt, ...) \
if (SRSLTE_DEBUG_ENABLED) \
log_h->warning(fmt, ##__VA_ARGS__)
#define Info(fmt, ...) \
if (SRSLTE_DEBUG_ENABLED) \
log_h->info(fmt, ##__VA_ARGS__)
#define Debug(fmt, ...) \
if (SRSLTE_DEBUG_ENABLED) \
log_h->debug(fmt, ##__VA_ARGS__)
namespace srsue {
sfn_sync::~sfn_sync()
{
srslte_ue_mib_free(&ue_mib);
}
void sfn_sync::init(srslte_ue_sync_t* ue_sync_,
const phy_args_t* phy_args_,
srslte::rf_buffer_t& buffer,
uint32_t buffer_max_samples_,
srslte::log* log_h_,
uint32_t nof_subframes)
{
log_h = log_h_;
ue_sync = ue_sync_;
phy_args = phy_args_;
timeout = nof_subframes;
mib_buffer = buffer;
buffer_max_samples = buffer_max_samples_;
// MIB decoder uses a single receiver antenna in logical channel 0
if (srslte_ue_mib_init(&ue_mib, buffer.get(0), SRSLTE_MAX_PRB)) {
Error("SYNC: Initiating UE MIB decoder\n");
}
}
bool sfn_sync::set_cell(srslte_cell_t cell_)
{
if (srslte_ue_mib_set_cell(&ue_mib, cell_)) {
Error("SYNC: Setting cell: initiating ue_mib\n");
return false;
}
reset();
return true;
}
void sfn_sync::reset()
{
cnt = 0;
srslte_ue_mib_reset(&ue_mib);
}
sfn_sync::ret_code sfn_sync::run_subframe(srslte_cell_t* cell_,
uint32_t* tti_cnt,
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload,
bool sfidx_only)
{
int ret = srslte_ue_sync_zerocopy(ue_sync, mib_buffer.to_cf_t(), buffer_max_samples);
if (ret < 0) {
Error("SYNC: Error calling ue_sync_get_buffer.\n");
return ERROR;
}
if (ret == 1) {
sfn_sync::ret_code ret2 = decode_mib(cell_, tti_cnt, nullptr, bch_payload, sfidx_only);
if (ret2 != SFN_NOFOUND) {
return ret2;
}
} else {
Info("SYNC: Waiting for PSS while trying to decode MIB (%d/%d)\n", cnt, timeout);
}
cnt++;
if (cnt >= timeout) {
cnt = 0;
return SFN_NOFOUND;
}
return IDLE;
}
sfn_sync::ret_code sfn_sync::decode_mib(srslte_cell_t* cell_,
uint32_t* tti_cnt,
srslte::rf_buffer_t* ext_buffer,
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload,
bool sfidx_only)
{
// If external buffer provided not equal to internal buffer, copy samples from channel/port 0
if (ext_buffer != nullptr) {
memcpy(mib_buffer.get(0), ext_buffer->get(0), sizeof(cf_t) * ue_sync->sf_len);
}
if (srslte_ue_sync_get_sfidx(ue_sync) == 0) {
// Skip MIB decoding if we are only interested in subframe 0
if (sfidx_only) {
if (tti_cnt) {
*tti_cnt = 0;
}
return SFX0_FOUND;
}
int sfn_offset = 0;
int n = srslte_ue_mib_decode(&ue_mib, bch_payload.data(), NULL, &sfn_offset);
switch (n) {
default:
Error("SYNC: Error decoding MIB while synchronising SFN");
return ERROR;
case SRSLTE_UE_MIB_FOUND:
uint32_t sfn;
srslte_pbch_mib_unpack(bch_payload.data(), cell_, &sfn);
sfn = (sfn + sfn_offset) % 1024;
if (tti_cnt) {
*tti_cnt = 10 * sfn;
// Check if SNR is below the minimum threshold
if (ue_mib.chest_res.snr_db < phy_args->in_sync_snr_db_th) {
Info("SYNC: MIB decoded, SNR is too low (%+.1f < %+.1f)\n",
ue_mib.chest_res.snr_db,
phy_args->in_sync_snr_db_th);
return SFN_NOFOUND;
}
Info("SYNC: DONE, SNR=%.1f dB, TTI=%d, sfn_offset=%d\n", ue_mib.chest_res.snr_db, *tti_cnt, sfn_offset);
}
reset();
return SFN_FOUND;
case SRSLTE_UE_MIB_NOTFOUND:
Info("SYNC: Found PSS but could not decode MIB. SNR=%.1f dB (%d/%d)\n", ue_mib.chest_res.snr_db, cnt, timeout);
return SFN_NOFOUND;
}
}
return IDLE;
}
}; // namespace srsue

453
srsue/src/phy/sync.cc
Unescape Escape View File

@ -78,7 +78,8 @@ void sync::init(srslte::radio_interface_phy* _radio,
return;
}
if (srslte_ue_sync_init_multi(&ue_sync, SRSLTE_MAX_PRB, false, radio_recv_callback, nof_rf_channels, this)) {
if (srslte_ue_sync_init_multi(&ue_sync, SRSLTE_MAX_PRB, false, radio_recv_callback, nof_rf_channels, this) !=
SRSLTE_SUCCESS) {
Error("SYNC: Initiating ue_sync\n");
return;
}
@ -98,7 +99,7 @@ void sync::init(srslte::radio_interface_phy* _radio,
// Start intra-frequency measurement
for (uint32_t i = 0; i < worker_com->args->nof_carriers; i++) {
auto q = new scell::intra_measure;
scell::intra_measure* q = new scell::intra_measure;
q->init(worker_com, stack, log_h);
intra_freq_meas.push_back(std::unique_ptr<scell::intra_measure>(q));
}
@ -309,13 +310,13 @@ bool sync::cell_select(const phy_interface_rrc_lte::phy_cell_t* new_cell)
intra_freq_meas[0]->set_primary_cell(current_earfcn, cell);
}
/* Change sampling rate if necessary */
// Change sampling rate if necessary
if (srate_mode != SRATE_CAMP) {
log_h->info("Cell Select: Setting CAMPING sampling rate\n");
set_sampling_rate();
}
/* SFN synchronization */
// SFN synchronization
phy_state.run_sfn_sync();
if (phy_state.is_camping()) {
Info("Cell Select: SFN synchronized. CAMPING...\n");
@ -333,69 +334,21 @@ bool sync::cell_is_camping()
return phy_state.is_camping();
}
/**
* MAIN THREAD
*
* The main thread process the SYNC state machine. Every state except IDLE must have exclusive access to
* all variables. If any change of cell configuration must be done, the thread must be in IDLE.
*
* On each state except campling, 1 function is called and the thread jumps to the next state based on the output.
*
* It has 3 states: Cell search, SFN synchronization, initial measurement and camping.
* - CELL_SEARCH: Initial Cell id and MIB acquisition. Uses 1.92 MHz sampling rate
* - CELL_SYNC: Full sampling rate, uses MIB to obtain SFN. When SFN is obtained, moves to CELL_CAMP
* - CELL_CAMP: Cell camping state. Calls the PHCH workers to process subframes and maintains cell synchronization.
* - IDLE: Receives and discards received samples. Does not maintain synchronization.
*
*/
void sync::run_thread()
void sync::run_cell_search_state()
{
sf_worker* worker = nullptr;
srslte_cell_t temp_cell = {};
bool force_camping_sfn_sync = false;
srslte::rf_buffer_t dummy_buffer(sync_nof_rx_subframes);
srslte::rf_buffer_t sync_buffer = {};
uint32_t prach_nof_sf = 0;
uint32_t prach_sf_cnt = 0;
cf_t* prach_ptr = NULL;
float prach_power = 0;
while (running) {
Debug("SYNC: state=%s, tti=%d\n", phy_state.to_string(), tti);
// If not camping, clear SFN sync
if (!phy_state.is_camping()) {
force_camping_sfn_sync = false;
}
if (log_phy_lib_h) {
log_phy_lib_h->step(tti);
}
switch (phy_state.run_state()) {
case sync_state::CELL_SEARCH:
/* Search for a cell in the current frequency and go to IDLE.
* The function search_p.run() will not return until the search finishes
*/
cell_search_ret = search_p.run(&cell, mib);
if (cell_search_ret == search::CELL_FOUND) {
stack->bch_decoded_ok(SYNC_CC_IDX, mib.data(), mib.size() / 8);
}
phy_state.state_exit();
break;
case sync_state::SFN_SYNC:
}
/* SFN synchronization using MIB. run_subframe() receives and processes 1 subframe
* and returns
*/
temp_cell = cell;
void sync::run_sfn_sync_state()
{
srslte_cell_t temp_cell = cell;
switch (sfn_p.run_subframe(&temp_cell, &tti, mib)) {
case sfn_sync::SFN_FOUND:
if (memcmp(&cell, &temp_cell, sizeof(srslte_cell_t))) {
if (memcmp(&cell, &temp_cell, sizeof(srslte_cell_t)) != 0) {
srslte_cell_fprint(stdout, &cell, 0);
srslte_cell_fprint(stdout, &temp_cell, 0);
log_h->error("Detected cell during SFN synchronization differs from configured cell. Cell reselection to "
@ -413,21 +366,10 @@ void sync::run_thread()
phy_state.state_exit(false);
break;
}
break;
case sync_state::CAMPING:
worker = (sf_worker*)workers_pool->wait_worker(tti);
if (worker) {
// Map carrier/antenna buffers to worker buffers
for (uint32_t c = 0; c < worker_com->args->nof_carriers; c++) {
for (uint32_t i = 0; i < worker_com->args->nof_rx_ant; i++) {
sync_buffer.set(c, i, worker_com->args->nof_rx_ant, worker->get_buffer(c, i));
}
}
// Primary Cell (PCell) Synchronization
switch (srslte_ue_sync_zerocopy(&ue_sync, sync_buffer.to_cf_t(), worker->get_buffer_len())) {
case 1:
void sync::run_camping_in_sync_state(sf_worker* worker, srslte::rf_buffer_t& sync_buffer)
{
// Check tti is synched with ue_sync
if (srslte_ue_sync_get_sfidx(&ue_sync) != tti % 10) {
@ -447,8 +389,9 @@ void sync::run_thread()
// Force decode MIB if required
if (force_camping_sfn_sync) {
uint32_t _tti = 0;
temp_cell = cell;
sync::sfn_sync::ret_code ret = sfn_p.decode_mib(&temp_cell, &_tti, &sync_buffer, mib);
srslte_cell_t temp_cell = cell;
sfn_sync::ret_code ret = sfn_p.decode_mib(&temp_cell, &_tti, &sync_buffer, mib);
if (ret == sfn_sync::SFN_FOUND) {
// Force tti
tti = _tti;
@ -456,7 +399,7 @@ void sync::run_thread()
// Disable
force_camping_sfn_sync = false;
if (memcmp(&cell, &temp_cell, sizeof(srslte_cell_t))) {
if (memcmp(&cell, &temp_cell, sizeof(srslte_cell_t)) != 0) {
log_h->error("Detected cell during SFN synchronization differs from configured cell. Cell "
"reselection to cells with different MIB is not supported\n");
log_h->console("Detected cell during SFN synchronization differs from configured cell. Cell "
@ -481,19 +424,17 @@ void sync::run_thread()
// Check if we need to TX a PRACH
if (prach_buffer->is_ready_to_send(tti)) {
prach_ptr = prach_buffer->generate(get_tx_cfo(), &prach_nof_sf, &prach_power);
if (!prach_ptr) {
if (prach_ptr == nullptr) {
Error("Generating PRACH\n");
}
}
/* Compute TX time: Any transmission happens in TTI+4 thus advance 4 ms the reception time */
srslte_timestamp_t rx_time, tx_time;
srslte_ue_sync_get_last_timestamp(&ue_sync, &rx_time);
srslte_timestamp_copy(&tx_time, &rx_time);
srslte_timestamp_add(&tx_time, 0, FDD_HARQ_DELAY_DL_MS * 1e-3);
// Compute TX time: Any transmission happens in TTI+4 thus advance 4 ms the reception time
srslte_timestamp_t tx_time;
srslte_ue_sync_get_last_timestamp(&ue_sync, &tx_time); // Get Rx Timestamp
srslte_timestamp_add(&tx_time, 0, FDD_HARQ_DELAY_DL_MS * 1e-3); // Add Tx delay
worker->set_prach(prach_ptr ? &prach_ptr[prach_sf_cnt * SRSLTE_SF_LEN_PRB(cell.nof_prb)] : nullptr,
prach_power);
worker->set_prach(prach_ptr ? &prach_ptr[prach_sf_cnt * SRSLTE_SF_LEN_PRB(cell.nof_prb)] : nullptr, prach_power);
// Set CFO for all Carriers
for (uint32_t cc = 0; cc < worker_com->args->nof_carriers; cc++) {
@ -516,7 +457,29 @@ void sync::run_thread()
// Start worker
worker_com->semaphore.push(worker);
workers_pool->start_worker(worker);
}
void sync::run_camping_state()
{
sf_worker* worker = (sf_worker*)workers_pool->wait_worker(tti);
srslte::rf_buffer_t sync_buffer = {};
if (worker == nullptr) {
// wait_worker() only returns NULL if it's being closed. Quit now to avoid unnecessary loops here
running = false;
return;
}
// Map carrier/antenna buffers to worker buffers
for (uint32_t c = 0; c < worker_com->args->nof_carriers; c++) {
for (uint32_t i = 0; i < worker_com->args->nof_rx_ant; i++) {
sync_buffer.set(c, i, worker_com->args->nof_rx_ant, worker->get_buffer(c, i));
}
}
// Primary Cell (PCell) Synchronization
switch (srslte_ue_sync_zerocopy(&ue_sync, sync_buffer.to_cf_t(), worker->get_buffer_len())) {
case 1:
run_camping_in_sync_state(worker, sync_buffer);
break;
case 0:
Warning("SYNC: Out-of-sync detected in PSS/SSS\n");
@ -531,14 +494,13 @@ void sync::run_thread()
break;
default:
radio_error();
worker->release();
break;
}
} else {
// wait_worker() only returns NULL if it's being closed. Quit now to avoid unnecessary loops here
running = false;
}
break;
case sync_state::IDLE:
void sync::run_idle_state()
{
if (radio_h->is_init()) {
uint32_t nsamples = 1920;
if (current_srate > 0) {
@ -546,7 +508,7 @@ void sync::run_thread()
}
Debug("Discarding %d samples\n", nsamples);
srslte_timestamp_t rx_time = {};
if (!radio_recv_fnc(dummy_buffer, nsamples, &rx_time)) {
if (radio_recv_fnc(dummy_buffer, nsamples, &rx_time) == SRSLTE_SUCCESS) {
log_h->console("SYNC: Receiving from radio while in IDLE_RX\n");
}
// If radio is in locked state returns immediately. In that case, do a 1 ms sleep
@ -558,11 +520,39 @@ void sync::run_thread()
Debug("Sleeping\n");
usleep(1000);
}
}
void sync::run_thread()
{
while (running) {
Debug("SYNC: state=%s, tti=%d\n", phy_state.to_string(), tti);
// If not camping, clear SFN sync
if (!phy_state.is_camping()) {
force_camping_sfn_sync = false;
}
if (log_phy_lib_h) {
log_phy_lib_h->step(tti);
}
switch (phy_state.run_state()) {
case sync_state::CELL_SEARCH:
run_cell_search_state();
break;
case sync_state::SFN_SYNC:
run_sfn_sync_state();
break;
case sync_state::CAMPING:
run_camping_state();
break;
case sync_state::IDLE:
run_idle_state();
break;
}
// Increase TTI counter
tti = (tti + 1) % 10240;
tti = TTI_ADD(tti, 1);
}
}
@ -786,7 +776,6 @@ void sync::set_sampling_rate()
return;
}
current_sflen = (uint32_t)SRSLTE_SF_LEN_PRB(cell.nof_prb);
if (current_srate != new_srate || srate_mode != SRATE_CAMP) {
current_srate = new_srate;
Info("SYNC: Setting sampling rate %.2f MHz\n", current_srate / 1000000);
@ -887,290 +876,6 @@ void sync::set_rx_gain(float gain)
radio_h->set_rx_gain_th(gain);
}
/*********
* Cell search class
*/
sync::search::~search()
{
srslte_ue_mib_sync_free(&ue_mib_sync);
srslte_ue_cellsearch_free(&cs);
}
void sync::search::init(srslte::rf_buffer_t& buffer_, srslte::log* log_h_, uint32_t nof_rx_channels, sync* parent)
{
log_h = log_h_;
p = parent;
buffer = buffer_;
if (srslte_ue_cellsearch_init_multi(&cs, 8, radio_recv_callback, nof_rx_channels, parent)) {
Error("SYNC: Initiating UE cell search\n");
}
srslte_ue_cellsearch_set_nof_valid_frames(&cs, 4);
if (srslte_ue_mib_sync_init_multi(&ue_mib_sync, radio_recv_callback, nof_rx_channels, parent)) {
Error("SYNC: Initiating UE MIB synchronization\n");
}
// Set options defined in expert section
p->set_ue_sync_opts(&cs.ue_sync, 0);
force_N_id_2 = -1;
}
void sync::search::reset()
{
srslte_ue_sync_reset(&ue_mib_sync.ue_sync);
}
float sync::search::get_last_cfo()
{
return srslte_ue_sync_get_cfo(&ue_mib_sync.ue_sync);
}
void sync::search::set_agc_enable(bool enable)
{
if (enable) {
srslte_rf_info_t* rf_info = p->radio_h->get_info();
srslte_ue_sync_start_agc(&ue_mib_sync.ue_sync,
callback_set_rx_gain,
rf_info->min_rx_gain,
rf_info->max_rx_gain,
p->radio_h->get_rx_gain());
} else {
ERROR("Error stop AGC not implemented\n");
}
}
sync::search::ret_code sync::search::run(srslte_cell_t* cell_, std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload)
{
srslte_cell_t new_cell = {};
srslte_ue_cellsearch_result_t found_cells[3];
bzero(found_cells, 3 * sizeof(srslte_ue_cellsearch_result_t));
/* Find a cell in the given N_id_2 or go through the 3 of them to find the strongest */
uint32_t max_peak_cell = 0;
int ret = SRSLTE_ERROR;
Info("SYNC: Searching for cell...\n");
log_h->console(".");
if (force_N_id_2 >= 0 && force_N_id_2 < 3) {
ret = srslte_ue_cellsearch_scan_N_id_2(&cs, force_N_id_2, &found_cells[force_N_id_2]);
max_peak_cell = force_N_id_2;
} else {
ret = srslte_ue_cellsearch_scan(&cs, found_cells, &max_peak_cell);
}
if (ret < 0) {
Error("SYNC: Error decoding MIB: Error searching PSS\n");
return ERROR;
} else if (ret == 0) {
Info("SYNC: Could not find any cell in this frequency\n");
return CELL_NOT_FOUND;
}
// Save result
new_cell.id = found_cells[max_peak_cell].cell_id;
new_cell.cp = found_cells[max_peak_cell].cp;
new_cell.frame_type = found_cells[max_peak_cell].frame_type;
float cfo = found_cells[max_peak_cell].cfo;
log_h->console("\n");
Info("SYNC: PSS/SSS detected: Mode=%s, PCI=%d, CFO=%.1f KHz, CP=%s\n",
new_cell.frame_type ? "TDD" : "FDD",
new_cell.id,
cfo / 1000,
srslte_cp_string(new_cell.cp));
if (srslte_ue_mib_sync_set_cell(&ue_mib_sync, new_cell)) {
Error("SYNC: Setting UE MIB cell\n");
return ERROR;
}
// Set options defined in expert section
p->set_ue_sync_opts(&ue_mib_sync.ue_sync, cfo);
srslte_ue_sync_reset(&ue_mib_sync.ue_sync);
/* Find and decode MIB */
int sfn_offset;
ret = srslte_ue_mib_sync_decode(&ue_mib_sync, 40, bch_payload.data(), &new_cell.nof_ports, &sfn_offset);
if (ret == 1) {
srslte_pbch_mib_unpack(bch_payload.data(), &new_cell, NULL);
// pack MIB and store inplace for PCAP dump
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN / 8> mib_packed;
srslte_bit_pack_vector(bch_payload.data(), mib_packed.data(), SRSLTE_BCH_PAYLOAD_LEN);
std::copy(std::begin(mib_packed), std::end(mib_packed), std::begin(bch_payload));
fprintf(stdout,
"Found Cell: Mode=%s, PCI=%d, PRB=%d, Ports=%d, CFO=%.1f KHz\n",
new_cell.frame_type ? "TDD" : "FDD",
new_cell.id,
new_cell.nof_prb,
new_cell.nof_ports,
cfo / 1000);
Info("SYNC: MIB Decoded: Mode=%s, PCI=%d, PRB=%d, Ports=%d, CFO=%.1f KHz\n",
new_cell.frame_type ? "TDD" : "FDD",
new_cell.id,
new_cell.nof_prb,
new_cell.nof_ports,
cfo / 1000);
if (!srslte_cell_isvalid(&new_cell)) {
Error("SYNC: Detected invalid cell.\n");
return CELL_NOT_FOUND;
}
// Save cell pointer
if (cell_) {
*cell_ = new_cell;
}
return CELL_FOUND;
} else if (ret == 0) {
Warning("SYNC: Found PSS but could not decode PBCH\n");
return CELL_NOT_FOUND;
} else {
Error("SYNC: Receiving MIB\n");
return ERROR;
}
}
/*********
* SFN synchronizer class
*/
sync::sfn_sync::~sfn_sync()
{
srslte_ue_mib_free(&ue_mib);
}
void sync::sfn_sync::init(srslte_ue_sync_t* ue_sync_,
const phy_args_t* phy_args_,
srslte::rf_buffer_t& buffer,
uint32_t buffer_max_samples_,
srslte::log* log_h_,
uint32_t nof_subframes)
{
log_h = log_h_;
ue_sync = ue_sync_;
phy_args = phy_args_;
timeout = nof_subframes;
mib_buffer = buffer;
buffer_max_samples = buffer_max_samples_;
// MIB decoder uses a single receiver antenna in logical channel 0
if (srslte_ue_mib_init(&ue_mib, buffer.get(0), SRSLTE_MAX_PRB)) {
Error("SYNC: Initiating UE MIB decoder\n");
}
}
bool sync::sfn_sync::set_cell(srslte_cell_t cell_)
{
if (srslte_ue_mib_set_cell(&ue_mib, cell_)) {
Error("SYNC: Setting cell: initiating ue_mib\n");
return false;
}
reset();
return true;
}
void sync::sfn_sync::reset()
{
cnt = 0;
srslte_ue_mib_reset(&ue_mib);
}
sync::sfn_sync::ret_code sync::sfn_sync::run_subframe(srslte_cell_t* cell_,
uint32_t* tti_cnt,
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload,
bool sfidx_only)
{
int ret = srslte_ue_sync_zerocopy(ue_sync, mib_buffer.to_cf_t(), buffer_max_samples);
if (ret < 0) {
Error("SYNC: Error calling ue_sync_get_buffer.\n");
return ERROR;
}
if (ret == 1) {
sync::sfn_sync::ret_code ret2 = decode_mib(cell_, tti_cnt, nullptr, bch_payload, sfidx_only);
if (ret2 != SFN_NOFOUND) {
return ret2;
}
} else {
Info("SYNC: Waiting for PSS while trying to decode MIB (%d/%d)\n", cnt, timeout);
}
cnt++;
if (cnt >= timeout) {
cnt = 0;
return SFN_NOFOUND;
}
return IDLE;
}
sync::sfn_sync::ret_code sync::sfn_sync::decode_mib(srslte_cell_t* cell_,
uint32_t* tti_cnt,
srslte::rf_buffer_t* ext_buffer,
std::array<uint8_t, SRSLTE_BCH_PAYLOAD_LEN>& bch_payload,
bool sfidx_only)
{
// If external buffer provided not equal to internal buffer, copy samples from channel/port 0
if (ext_buffer != nullptr) {
memcpy(mib_buffer.get(0), ext_buffer->get(0), sizeof(cf_t) * ue_sync->sf_len);
}
if (srslte_ue_sync_get_sfidx(ue_sync) == 0) {
// Skip MIB decoding if we are only interested in subframe 0
if (sfidx_only) {
if (tti_cnt) {
*tti_cnt = 0;
}
return SFX0_FOUND;
}
int sfn_offset = 0;
int n = srslte_ue_mib_decode(&ue_mib, bch_payload.data(), NULL, &sfn_offset);
switch (n) {
default:
Error("SYNC: Error decoding MIB while synchronising SFN");
return ERROR;
case SRSLTE_UE_MIB_FOUND:
uint32_t sfn;
srslte_pbch_mib_unpack(bch_payload.data(), cell_, &sfn);
sfn = (sfn + sfn_offset) % 1024;
if (tti_cnt) {
*tti_cnt = 10 * sfn;
// Check if SNR is below the minimum threshold
if (ue_mib.chest_res.snr_db < phy_args->in_sync_snr_db_th) {
Info("SYNC: MIB decoded, SNR is too low (%+.1f < %+.1f)\n",
ue_mib.chest_res.snr_db,
phy_args->in_sync_snr_db_th);
return SFN_NOFOUND;
}
Info("SYNC: DONE, SNR=%.1f dB, TTI=%d, sfn_offset=%d\n", ue_mib.chest_res.snr_db, *tti_cnt, sfn_offset);
}
reset();
return SFN_FOUND;
case SRSLTE_UE_MIB_NOTFOUND:
Info("SYNC: Found PSS but could not decode MIB. SNR=%.1f dB (%d/%d)\n", ue_mib.chest_res.snr_db, cnt, timeout);
return SFN_NOFOUND;
}
}
return IDLE;
}
/**********
* PHY measurements
*

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