Added option to force the DL/UL frequency at the UE

srsenb/enb.conf.example

@@ -45,7 +45,9 @@ drb_config = drb.conf
 # tx_gain: Transmit gain (dB). 
 # rx_gain: Optional receive gain (dB). If disabled, AGC if enabled
 #
-# Optional parameters: 
+# Optional parameters:
+# dl_freq:            Override DL frequency corresponding to dl_earfcn
+# ul_freq:            Override UL frequency corresponding to dl_earfcn (must be set if dl_freq is set)
 # device_name:        Device driver family. Supported options: "auto" (uses first found), "UHD" or "bladeRF" 
 # device_args:        Arguments for the device driver. Options are "auto" or any string. 
 #                     Default for UHD: "recv_frame_size=9232,send_frame_size=9232"

srsue/hdr/phy/phch_recv.h

@@ -53,6 +53,7 @@ public:
   void set_agc_enable(bool enable);
 
   void    set_earfcn(std::vector<uint32_t> earfcn);
+  void    force_freq(float dl_freq, float ul_freq);
 
   void    reset_sync();
   void    cell_search_start();
@@ -171,6 +172,10 @@ private:
   int    cell_meas_rsrp();
   int    cell_search(int force_N_id_2 = -1);
   bool   set_cell();
+
+  float dl_freq;
+  float ul_freq;
+
 };
 
 } // namespace srsue

srsue/hdr/phy/phy.h

@@ -76,6 +76,7 @@ public:
   void write_trace(std::string filename);
 
   void set_earfcn(std::vector<uint32_t> earfcns);
+  void force_freq(float dl_freq, float ul_freq);
 
   /********** RRC INTERFACE ********************/
   void    reset();
@@ -167,7 +168,7 @@ private:
   
   /* Current time advance */
   uint32_t     n_ta;
-    
+
   bool init_(srslte::radio *radio_handler, mac_interface_phy *mac, srslte::log *log_h, bool do_agc, uint32_t nof_workers);
   void set_default_args(phy_args_t *args);
   bool check_args(phy_args_t *args); 

srsue/src/main.cc

@@ -65,6 +65,8 @@ void parse_args(all_args_t *args, int argc, char *argv[]) {
   common.add_options()
     ("rf.dl_earfcn", bpo::value<uint32_t>(&args->rf.dl_earfcn)->default_value(3400), "Downlink EARFCN")
     ("rf.freq_offset", bpo::value<float>(&args->rf.freq_offset)->default_value(0), "(optional) Frequency offset")
+    ("rf.dl_freq",     bpo::value<float>(&args->rf.dl_freq)->default_value(-1),      "Downlink Frequency (if positive overrides EARFCN)")
+    ("rf.ul_freq",     bpo::value<float>(&args->rf.ul_freq)->default_value(-1),      "Uplink Frequency (if positive overrides EARFCN)")
     ("rf.rx_gain", bpo::value<float>(&args->rf.rx_gain)->default_value(-1), "Front-end receiver gain")
     ("rf.tx_gain", bpo::value<float>(&args->rf.tx_gain)->default_value(-1), "Front-end transmitter gain")
     ("rf.nof_rx_ant", bpo::value<uint32_t>(&args->rf.nof_rx_ant)->default_value(1), "Number of RX antennas")

srsue/src/phy/phch_recv.cc

@@ -63,6 +63,8 @@ double callback_set_rx_gain(void *h, double gain) {
 
 
 phch_recv::phch_recv() {
+  dl_freq = -1;
+  ul_freq = -1;
   bzero(&cell, sizeof(srslte_cell_t));
   running = false;
 }
@@ -445,6 +447,11 @@ void phch_recv::set_earfcn(std::vector<uint32_t> earfcn) {
   this->earfcn = earfcn;
 }
 
+void phch_recv::force_freq(float dl_freq, float ul_freq) {
+  this->dl_freq = dl_freq;
+  this->ul_freq = ul_freq;
+}
+
 bool phch_recv::stop_sync() {
 
   wait_radio_reset();
@@ -568,17 +575,25 @@ bool phch_recv::cell_select(uint32_t earfcn, srslte_cell_t cell) {
 
 bool phch_recv::set_frequency()
 {
-  double dl_freq = 1e6*srslte_band_fd(current_earfcn);
-  double ul_freq = 1e6*srslte_band_fu(srslte_band_ul_earfcn(current_earfcn));
-  if (dl_freq > 0 && ul_freq > 0) {
+  double set_dl_freq = 0;
+  double set_ul_freq = 0;
+
+  if (this->dl_freq > 0 && this->ul_freq > 0) {
+    set_dl_freq = this->dl_freq;
+    set_ul_freq = this->ul_freq;
+  } else {
+    set_dl_freq = 1e6*srslte_band_fd(current_earfcn);
+    set_ul_freq = 1e6*srslte_band_fu(srslte_band_ul_earfcn(current_earfcn));
+  }
+  if (set_dl_freq > 0 && set_ul_freq > 0) {
     log_h->info("SYNC:  Set DL EARFCN=%d, f_dl=%.1f MHz, f_ul=%.1f MHz\n",
-                current_earfcn, dl_freq / 1e6, ul_freq / 1e6);
+                current_earfcn, set_dl_freq / 1e6, set_ul_freq / 1e6);
 
     log_h->console("Searching cell in DL EARFCN=%d, f_dl=%.1f MHz, f_ul=%.1f MHz\n",
-                current_earfcn, dl_freq / 1e6, ul_freq / 1e6);
+                current_earfcn, set_dl_freq / 1e6, set_ul_freq / 1e6);
 
-    radio_h->set_rx_freq(dl_freq);
-    radio_h->set_tx_freq(ul_freq);
+    radio_h->set_rx_freq(set_dl_freq);
+    radio_h->set_tx_freq(set_ul_freq);
     ul_dl_factor = radio_h->get_tx_freq()/radio_h->get_rx_freq();
 
     srslte_ue_sync_reset(&ue_sync);

srsue/src/phy/phy.cc

@@ -332,6 +332,11 @@ void phy::set_earfcn(vector< uint32_t > earfcns)
   sf_recv.set_earfcn(earfcns);
 }
 
+void phy::force_freq(float dl_freq, float ul_freq)
+{
+  sf_recv.force_freq(dl_freq, ul_freq);
+}
+
 bool phy::sync_status()
 {
   return sf_recv.status_is_sync();

srsue/src/ue.cc

@@ -193,6 +193,10 @@ bool ue::init(all_args_t *args_)
   earfcn_list.push_back(args->rf.dl_earfcn);
   phy.set_earfcn(earfcn_list);
 
+  if (args->rf.dl_freq > 0 && args->rf.ul_freq > 0) {
+    phy.force_freq(args->rf.dl_freq, args->rf.ul_freq);
+  }
+
   printf("Waiting PHY to initialize...\n");
   phy.wait_initialize();
   phy.configure_ul_params();

srsue/ue.conf.example

@@ -9,6 +9,8 @@
 # rx_gain: Optional receive gain (dB). If disabled, AGC if enabled
 #
 # Optional parameters: 
+# dl_freq:            Override DL frequency corresponding to dl_earfcn
+# ul_freq:            Override UL frequency corresponding to dl_earfcn
 # nof_rx_ant:         Number of RX antennas (Default 1, supported 1 or 2)
 # device_name:        Device driver family. Supported options: "auto" (uses first found), "UHD" or "bladeRF" 
 # device_args:        Arguments for the device driver. Options are "auto" or any string.