Add downlink PAPR measurement to eNB.

lib/include/srsran/interfaces/enb_command_interface.h

@@ -28,6 +28,10 @@ namespace srsenb {
 class enb_command_interface
 {
 public:
+  /**
+   * Trigger downlink singnal measurements.
+   */
+  virtual void cmd_cell_measure() = 0;
   /**
    * Sets the relative gain of a cell from it's index (following rr.conf) order.
    * @param cell_id Provides a cell identifier

srsenb/hdr/enb.h

@@ -142,6 +142,7 @@ class enb : public enb_metrics_interface, enb_command_interface
   bool get_metrics(enb_metrics_t* m) override;
 
   // eNodeB command interface
+  void cmd_cell_measure() override;
   void cmd_cell_gain(uint32_t cell_id, float gain) override;
 
 private:

srsenb/hdr/phy/enb_phy_base.h

@@ -46,6 +46,8 @@ class enb_phy_base
 
   virtual void get_metrics(std::vector<phy_metrics_t>& m) = 0;
 
+  virtual void cmd_cell_measure() = 0;
+
   virtual void cmd_cell_gain(uint32_t cell_idx, float gain_db) = 0;
 };
 

srsenb/hdr/phy/phy.h

@@ -63,6 +63,8 @@ class phy final : public enb_phy_base, public phy_interface_stack_lte, public sr
 
   void get_metrics(std::vector<phy_metrics_t>& metrics) override;
 
+  void cmd_cell_measure() override;
+
   void cmd_cell_gain(uint32_t cell_id, float gain_db) override;
 
   void radio_overflow() override{};

srsenb/hdr/phy/phy_common.h

@@ -170,6 +170,19 @@ class phy_common
     return c;
   };
 
+  void set_cell_measure_trigger()
+  {
+    // Trigger on LTE cell
+    for (auto it_lte = cell_list_lte.begin(); it_lte != cell_list_lte.end(); ++it_lte) {
+      it_lte->dl_measure = true;
+    }
+
+    // Trigger on NR cell
+    for (auto it_nr = cell_list_nr.begin(); it_nr != cell_list_nr.end(); ++it_nr) {
+      it_nr->dl_measure = true;
+    }
+  }
+
   void set_cell_gain(uint32_t cell_id, float gain_db)
   {
     // Find LTE cell
@@ -195,6 +208,20 @@ class phy_common
     srsran::console("cell ID %d not found\n", cell_id);
   }
 
+  bool get_cell_measure_trigger(uint32_t cc_idx)
+  {
+    if (cc_idx < cell_list_lte.size()) {
+      return cell_list_lte.at(cc_idx).dl_measure;
+    }
+
+    cc_idx -= cell_list_lte.size();
+    if (cc_idx < cell_list_nr.size()) {
+      return cell_list_nr.at(cc_idx).dl_measure;
+    }
+
+    return false;
+  }
+
   float get_cell_gain(uint32_t cc_idx)
   {
     if (cc_idx < cell_list_lte.size()) {
@@ -209,6 +236,20 @@ class phy_common
     return 0.0f;
   }
 
+  void clear_cell_measure_trigger(uint32_t cc_idx)
+  {
+    if (cc_idx < cell_list_lte.size()) {
+      cell_list_lte.at(cc_idx).dl_measure = false;
+    }
+
+    cc_idx -= cell_list_lte.size();
+    if (cc_idx < cell_list_nr.size()) {
+      cell_list_nr.at(cc_idx).dl_measure = false;
+    }
+
+    return;
+  }
+
   // Common Physical Uplink DMRS configuration
   srsran_refsignal_dmrs_pusch_cfg_t dmrs_pusch_cfg = {};
 

srsenb/hdr/phy/phy_interfaces.h

@@ -40,6 +40,7 @@ struct phy_cell_cfg_t {
   uint32_t      root_seq_idx;
   uint32_t      num_ra_preambles;
   float         gain_db;
+  bool          dl_measure;
 };
 
 struct phy_cell_cfg_nr_t {
@@ -51,6 +52,7 @@ struct phy_cell_cfg_nr_t {
   uint32_t            root_seq_idx;
   uint32_t            num_ra_preambles;
   float               gain_db;
+  bool                dl_measure;
 };
 
 typedef std::vector<phy_cell_cfg_t>    phy_cell_cfg_list_t;

srsenb/hdr/phy/vnf_phy_nr.h

@@ -54,6 +54,11 @@ class vnf_phy_nr : public srsenb::enb_phy_base, public srsenb::phy_interface_sta
   int dl_config_request(const dl_config_request_t& request) override;
   int tx_request(const tx_request_t& request) override;
 
+  void cmd_cell_measure() override
+  {
+    // Do nothing
+  }
+
   void cmd_cell_gain(uint32_t cell_idx, float gain_db) override
   {
     // Do nothing

srsenb/src/enb.cc

@@ -216,6 +216,11 @@ void enb::cmd_cell_gain(uint32_t cell_id, float gain)
   phy->cmd_cell_gain(cell_id, gain);
 }
 
+void enb::cmd_cell_measure()
+{
+  phy->cmd_cell_measure();
+}
+
 std::string enb::get_build_mode()
 {
   return std::string(srsran_get_build_mode());

srsenb/src/main.cc

@@ -439,6 +439,7 @@ static void* input_loop(metrics_stdout* metrics, srsenb::enb_command_interface*
 {
   struct pollfd pfd = {STDIN_FILENO, POLLIN, 0};
   string        input_line;
+
   while (running) {
     int ret = poll(&pfd, 1, 1000); // query stdin with a timeout of 1000ms
     if (ret == 1) {
@@ -458,6 +459,9 @@ static void* input_loop(metrics_stdout* metrics, srsenb::enb_command_interface*
             cout << "Enter t to restart trace." << endl;
           }
           metrics->toggle_print(do_metrics);
+        } else if (cmd[0] == "m") {
+          // Trigger cell measurements
+          control->cmd_cell_measure();
         } else if (cmd[0] == "q") {
           raise(SIGTERM);
         } else if (cmd[0] == "cell_gain") {
@@ -475,6 +479,7 @@ static void* input_loop(metrics_stdout* metrics, srsenb::enb_command_interface*
         } else {
           cout << "Available commands: " << endl;
           cout << "          t: starts console trace" << endl;
+          cout << "          m: downlink signal measurements" << endl;
           cout << "          q: quit srsenb" << endl;
           cout << "  cell_gain: set relative cell gain" << endl;
           cout << endl;

srsenb/src/phy/lte/cc_worker.cc

@@ -18,6 +18,7 @@
  * and at http://www.gnu.org/licenses/.
  *
  */
+#include <iomanip>
 
 #include "srsran/common/threads.h"
 #include "srsran/srsran.h"
@@ -262,6 +263,24 @@ void cc_worker::work_dl(const srsran_dl_sf_cfg_t&            dl_sf_cfg,
       srsran_vec_sc_prod_cfc(signal_buffer_tx[i], scale, signal_buffer_tx[i], sf_len);
     }
   }
+
+  // Measure if flag was triggered
+  bool cell_meas_flag = phy->get_cell_measure_trigger(cc_idx);
+  if (cell_meas_flag == true) {
+    uint32_t sf_len = SRSRAN_SF_LEN_PRB(enb_dl.cell.nof_prb);
+    for (uint32_t i = 0; i < enb_dl.cell.nof_ports; i++) {
+      // PAPR measure
+      std::vector<float> sigSq(sf_len);
+      srsran_vec_abs_square_cf(signal_buffer_tx[i], sigSq.data(), sf_len);
+      float sigPMax  = sigSq[srsran_vec_max_abs_fi(sigSq.data(), sf_len)];
+      float sigPMean = srsran_vec_acc_ff(sigSq.data(), sf_len) / float(sf_len);
+      float PAPRdB   = 10.0f * log10(sigPMax / sigPMean);
+      std::cout << "Cell #" << cc_idx << " port #" << i << " PAPR = " << std::setprecision(4) << PAPRdB << " dB "
+                << std::endl;
+    }
+    // clear measurement flag on cell
+    phy->clear_cell_measure_trigger(cc_idx);
+  }
 }
 
 void cc_worker::decode_pusch_rnti(stack_interface_phy_lte::ul_sched_grant_t& ul_grant,

srsenb/src/phy/phy.cc

@@ -243,6 +243,11 @@ void phy::cmd_cell_gain(uint32_t cell_id, float gain_db)
   workers_common.set_cell_gain(cell_id, gain_db);
 }
 
+void phy::cmd_cell_measure()
+{
+  workers_common.set_cell_measure_trigger();
+}
+
 /***** RRC->PHY interface **********/
 
 void phy::set_config(uint16_t rnti, const phy_rrc_cfg_list_t& phy_cfg_list)