rf: allow 5G custom tx/rx frequencies

Signed-off-by: Nikos Apostolakis <nikos.apostolakis@srs.io>

Author: kaposnick

lib/include/srsran/interfaces/ue_nr_interfaces.h

@@ -231,6 +231,8 @@ struct phy_args_nr_t {
   float                  trs_sinr_ema_alpha    = 0.1f; ///< SINR measurement exponential average alpha
   float                  trs_cfo_ema_alpha     = 0.1f; ///< RSRP measurement exponential average alpha
   bool                   enable_worker_cfo     = true; ///< Enable/Disable open loop CFO correction at the workers
+  float                  dl_freq               = -1.0f;
+  float                  ul_freq               = -1.0f;
 
   phy_args_nr_t()
   {

srsue/hdr/phy/nr/sync_sa.h

@@ -54,6 +54,8 @@ class sync_sa : public srsran::thread, public srsran::phy_common_interface
     float                       pbch_dmrs_thr   = 0.0f; ///< PBCH DMRS correlation detection threshold (0 means auto)
     float                       cfo_alpha       = 0.0f; ///< CFO averaging alpha (0 means auto)
     int                         thread_priority = 1;
+    double                      dl_freq_override_hz = -1;
+    double                      ul_freq_override_hz = -1;
 
     cell_search::args_t get_cell_search() const
     {
@@ -115,6 +117,8 @@ class sync_sa : public srsran::thread, public srsran::phy_common_interface
   const static uint32_t        cell_search_max_trials = 100;
   uint32_t                     sfn_sync_nof_trials    = 0;
   const static uint32_t        sfn_sync_max_trials    = 100;
+  double                       dl_freq_override_hz    = -1;
+  double                       ul_freq_override_hz    = -1;
 
   cell_search::ret_t cs_ret;
   cell_search        searcher;

srsue/src/phy/phy_nr_sa.cc

@@ -68,7 +68,8 @@ phy_nr_sa::phy_nr_sa(const char* logname) :
   logger_phy_lib(srslog::fetch_basic_logger("PHY_LIB")),
   sync(logger, workers),
   workers(logger, 4)
-{}
+{
+}
 
 int phy_nr_sa::init(const phy_args_nr_t& args_, stack_interface_phy_nr* stack_, srsran::radio_interface_phy* radio_)
 {
@@ -106,6 +107,8 @@ void phy_nr_sa::init_background()
   nr::sync_sa::args_t sync_args = {};
   sync_args.srate_hz            = args.srate_hz;
   sync_args.thread_priority     = args.slot_recv_thread_prio;
+  sync_args.ul_freq_override_hz = args.ul_freq;
+  sync_args.dl_freq_override_hz = args.dl_freq;
   if (not sync.init(sync_args, stack, radio)) {
     logger.error("Error initialising SYNC");
     return;

srsue/src/phy/sync_sa.cc

@@ -26,7 +26,8 @@ namespace srsue {
 namespace nr {
 sync_sa::sync_sa(srslog::basic_logger& logger_, worker_pool& workers_) :
   logger(logger_), workers(workers_), slot_synchronizer(logger_), searcher(logger_), ta(logger_), srsran::thread("SYNC")
-{}
+{
+}
 
 sync_sa::~sync_sa()
 {
@@ -37,10 +38,12 @@ sync_sa::~sync_sa()
 
 bool sync_sa::init(const args_t& args, stack_interface_phy_nr* stack_, srsran::radio_interface_phy* radio_)
 {
-  stack    = stack_;
-  radio    = radio_;
-  srate_hz = args.srate_hz;
-  slot_sz  = (uint32_t)(args.srate_hz / 1000.0f);
+  stack               = stack_;
+  radio               = radio_;
+  srate_hz            = args.srate_hz;
+  slot_sz             = (uint32_t)(args.srate_hz / 1000.0f);
+  dl_freq_override_hz = args.dl_freq_override_hz;
+  ul_freq_override_hz = args.ul_freq_override_hz;
 
   // Initialise cell search internal object
   if (not searcher.init(args.get_cell_search())) {
@@ -149,7 +152,12 @@ cell_search::ret_t sync_sa::cell_search_run(const cell_search::cfg_t& cfg)
 
   // tune radio
   logger.info("Tuning Rx channel %d to %.2f MHz", 0, cfg.center_freq_hz / 1e6);
-  radio->set_rx_freq(0, cfg.center_freq_hz);
+  double dl_freq_applied = cfg.center_freq_hz;
+  if (dl_freq_override_hz > 0) {
+    dl_freq_applied = dl_freq_override_hz;
+    logger.info("Overriding Rx channel %d to %.2f MHz", 0, dl_freq_override_hz / 1e6);
+  }
+  radio->set_rx_freq(0, dl_freq_applied);
 
   if (not searcher.start(cfg)) {
     logger.error("Sync: failed to start cell search");
@@ -185,9 +193,20 @@ rrc_interface_phy_nr::cell_select_result_t sync_sa::cell_select_run(const phy_in
 
   // tune radio
   logger.info("Tuning Rx channel %d to %.2f MHz", 0, req.carrier.dl_center_frequency_hz / 1e6);
-  radio->set_rx_freq(0, req.carrier.dl_center_frequency_hz);
+  double dl_freq_applied = req.carrier.dl_center_frequency_hz;
+  if (dl_freq_override_hz > 0) {
+    dl_freq_applied = dl_freq_override_hz;
+    logger.info("Overriding Rx channel %d to %.2f MHz", 0, dl_freq_override_hz / 1e6);
+  }
+  radio->set_rx_freq(0, dl_freq_applied);
+
   logger.info("Tuning Tx channel %d to %.2f MHz", 0, req.carrier.ul_center_frequency_hz / 1e6);
-  radio->set_tx_freq(0, req.carrier.ul_center_frequency_hz);
+  double ul_freq_applied = req.carrier.ul_center_frequency_hz;
+  if (ul_freq_override_hz > 0) {
+    ul_freq_applied = ul_freq_override_hz;
+    logger.info("Overriding Rx channel %d to %.2f MHz", 0, ul_freq_override_hz / 1e6);
+  }
+  radio->set_tx_freq(0, ul_freq_applied);
 
   // Configure cell
   srsran_ue_sync_nr_cfg_t cfg = {};

srsue/src/ue.cc

@@ -92,6 +92,8 @@ int ue::init(const all_args_t& args_)
   phy_args_nr.log                  = args.phy.log;
   phy_args_nr.store_pdsch_ko       = args.phy.nr_store_pdsch_ko;
   phy_args_nr.srate_hz             = args.rf.srate_hz;
+  phy_args_nr.dl_freq              = args.phy.dl_freq;
+  phy_args_nr.ul_freq              = args.phy.ul_freq;
 
   // init layers
   if (args.phy.nof_lte_carriers == 0) {
@@ -279,7 +281,7 @@ int ue::parse_args(const all_args_t& args_)
   // Consider Carrier Aggregation support if more than one
   args.stack.rrc.nof_lte_carriers = args.phy.nof_lte_carriers;
   args.stack.rrc.nof_nr_carriers  = args.phy.nof_nr_carriers;
-  args.stack.rrc.support_ca = (args.phy.nof_lte_carriers > 1);
+  args.stack.rrc.support_ca       = (args.phy.nof_lte_carriers > 1);
 
   // Make sure fix sampling rate is set for SA mode
   if (args.phy.nof_lte_carriers == 0 and not std::isnormal(args.rf.srate_hz)) {