From 170fbefbf5c7f2ba48dd7f2fcb6c9beb885b3261 Mon Sep 17 00:00:00 2001
From: Xavier Arteaga <xavier@softwareradiosystems.com>
Date: Mon, 17 May 2021 12:06:37 +0200
Subject: [PATCH] Avoid SCell receiver to copy

---
 srsue/hdr/phy/scell/scell_recv.h         | 26 ++++++++++++++++--------
 srsue/src/phy/scell/intra_measure_lte.cc |  7 +------
 srsue/src/phy/scell/scell_recv.cc        | 15 +++++++-------
 3 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/srsue/hdr/phy/scell/scell_recv.h b/srsue/hdr/phy/scell/scell_recv.h
index 4242c2360..0ac24d40a 100644
--- a/srsue/hdr/phy/scell/scell_recv.h
+++ b/srsue/hdr/phy/scell/scell_recv.h
@@ -26,18 +26,26 @@ class scell_recv
 public:
   explicit scell_recv(srslog::basic_logger& logger) : logger(logger) {}
 
-  void               init(uint32_t max_sf_window);
-  void               deinit();
-  void               reset();
-  std::set<uint32_t> find_cells(const cf_t* input_buffer, const srsran_cell_t serving_cell, const uint32_t nof_sf);
+  void init(uint32_t max_sf_window);
+  void deinit();
+  void reset();
+
+  /**
+   * @brief Find neighbour cells in a given buffer
+   * @param input_buffer Provides the baseband samples
+   * @param serving_cell Current serving cell
+   * @param nof_sf Number of subframes contained in the baseband buffer
+   * @param found_cell_ids Provides a set where to insert the found cell identifiers (PCIs)
+   */
+  void find_cells(const cf_t*          input_buffer,
+                  const srsran_cell_t& serving_cell,
+                  const uint32_t&      nof_sf,
+                  std::set<uint32_t>&  found_cell_ids);
 
 private:
-  // 36.133 9.1.2.1 for band 7
-  constexpr static float ABSOLUTE_RSRP_THRESHOLD_DBM = -125;
-
-  cf_t*                 sf_buffer[SRSRAN_MAX_PORTS];
+  cf_t*                 sf_buffer[SRSRAN_MAX_PORTS] = {};
   srslog::basic_logger& logger;
-  srsran_sync_t         sync_find;
+  srsran_sync_t         sync_find = {};
 
   uint32_t current_fft_sz;
 };
diff --git a/srsue/src/phy/scell/intra_measure_lte.cc b/srsue/src/phy/scell/intra_measure_lte.cc
index 9a09c8320..75a09b14a 100644
--- a/srsue/src/phy/scell/intra_measure_lte.cc
+++ b/srsue/src/phy/scell/intra_measure_lte.cc
@@ -52,12 +52,7 @@ void intra_measure_lte::measure_rat(const measure_context_t& context, std::vecto
   std::set<uint32_t> cells_to_measure = context.active_pci;
 
   // Detect new cells using PSS/SSS
-  std::set<uint32_t> detected_cells = scell_rx.find_cells(buffer.data(), serving_cell, context.meas_len_ms);
-
-  // Add detected cells to the list of cells to measure
-  for (const uint32_t& c : detected_cells) {
-    cells_to_measure.insert(c);
-  }
+  scell_rx.find_cells(buffer.data(), serving_cell, context.meas_len_ms, cells_to_measure);
 
   // Initialise empty neighbour cell list
   std::vector<phy_meas_t> neighbour_cells = {};
diff --git a/srsue/src/phy/scell/scell_recv.cc b/srsue/src/phy/scell/scell_recv.cc
index e15a0e524..a84ba6e19 100644
--- a/srsue/src/phy/scell/scell_recv.cc
+++ b/srsue/src/phy/scell/scell_recv.cc
@@ -68,18 +68,18 @@ void scell_recv::reset()
   current_fft_sz = 0;
 }
 
-std::set<uint32_t>
-scell_recv::find_cells(const cf_t* input_buffer, const srsran_cell_t serving_cell, const uint32_t nof_sf)
+void scell_recv::find_cells(const cf_t*          input_buffer,
+                            const srsran_cell_t& serving_cell,
+                            const uint32_t&      nof_sf,
+                            std::set<uint32_t>&  found_cell_ids)
 {
-  std::set<uint32_t> found_cell_ids = {};
-
   uint32_t fft_sz = srsran_symbol_sz(serving_cell.nof_prb);
   uint32_t sf_len = SRSRAN_SF_LEN(fft_sz);
 
   if (fft_sz != current_fft_sz) {
     if (srsran_sync_resize(&sync_find, nof_sf * sf_len, 5 * sf_len, fft_sz)) {
       logger.error("Error resizing sync nof_sf=%d, sf_len=%d, fft_sz=%d", nof_sf, sf_len, fft_sz);
-      return found_cell_ids;
+      return;
     }
     current_fft_sz = fft_sz;
   }
@@ -88,7 +88,6 @@ scell_recv::find_cells(const cf_t* input_buffer, const srsran_cell_t serving_cel
   int      cell_id  = 0;
 
   for (uint32_t n_id_2 = 0; n_id_2 < 3; n_id_2++) {
-
     if (n_id_2 != (serving_cell.id % 3)) {
       srsran_sync_set_N_id_2(&sync_find, n_id_2);
 
@@ -108,7 +107,7 @@ scell_recv::find_cells(const cf_t* input_buffer, const srsran_cell_t serving_cel
         sync_res = srsran_sync_find(&sync_find, input_buffer, sf5_cnt * 5 * sf_len, &peak_idx);
         if (sync_res == SRSRAN_SYNC_ERROR) {
           logger.error("INTRA: Error calling sync_find()");
-          return found_cell_ids;
+          return;
         }
 
         if (sync_find.peak_value > max_peak && sync_res == SRSRAN_SYNC_FOUND && srsran_sync_sss_detected(&sync_find)) {
@@ -144,7 +143,7 @@ scell_recv::find_cells(const cf_t* input_buffer, const srsran_cell_t serving_cel
       }
     }
   }
-  return found_cell_ids;
+  return;
 }
 
 } // namespace scell