From 1bffebe0bfc7954081e8ef83f9e4ebbc79f521b4 Mon Sep 17 00:00:00 2001
From: Xavier Arteaga <xavier.arteaga@softwareradiosystems.com>
Date: Thu, 7 Oct 2021 16:59:00 +0200
Subject: [PATCH] Removed cached PRACH signals

---
 srsue/hdr/phy/prach.h  | 40 ++++++++++++++--------------------------
 srsue/src/phy/prach.cc | 33 +++------------------------------
 2 files changed, 17 insertions(+), 56 deletions(-)

diff --git a/srsue/hdr/phy/prach.h b/srsue/hdr/phy/prach.h
index cfe9a272d..f858f3266 100644
--- a/srsue/hdr/phy/prach.h
+++ b/srsue/hdr/phy/prach.h
@@ -41,37 +41,25 @@ public:
 private:
   bool generate_buffer(uint32_t f_idx);
 
-  bool is_buffer_generated(uint32_t f_idx, uint32_t preamble_index) const
-  {
-    return buffer_bitmask.test(f_idx * 64 + preamble_index);
-  }
-
-  void set_buffer_as_generated(uint32_t f_idx, uint32_t preamble_index)
-  {
-    buffer_bitmask.set(f_idx * 64 + preamble_index);
-  }
-
 private:
   static constexpr unsigned MAX_LEN_SF    = 3;
   static constexpr unsigned max_fs        = 12;
   static constexpr unsigned max_preambles = 64;
 
-  srslog::basic_logger&                                logger;
-  srsran_prach_t                                       prach_obj        = {};
-  srsran_cell_t                                        cell             = {};
-  srsran_cfo_t                                         cfo_h            = {};
-  srsran_prach_cfg_t                                   cfg              = {};
-  std::array<std::array<cf_t*, max_preambles>, max_fs> buffer           = {};
-  cf_t*                                                signal_buffer    = nullptr;
-  int                                                  preamble_idx     = -1;
-  uint32_t                                             len              = 0;
-  int                                                  allowed_subframe = 0;
-  int                                                  transmitted_tti  = 0;
-  float                                                target_power_dbm = 0;
-  bool                                                 mem_initiated    = false;
-  bool                                                 cell_initiated   = false;
-  std::bitset<max_fs * max_preambles>                  buffer_bitmask;
-  mutable std::mutex                                   mutex;
+  srslog::basic_logger& logger;
+  srsran_prach_t        prach_obj        = {};
+  srsran_cell_t         cell             = {};
+  srsran_cfo_t          cfo_h            = {};
+  srsran_prach_cfg_t    cfg              = {};
+  cf_t*                 signal_buffer    = nullptr;
+  int                   preamble_idx     = -1;
+  uint32_t              len              = 0;
+  int                   allowed_subframe = 0;
+  int                   transmitted_tti  = 0;
+  float                 target_power_dbm = 0;
+  bool                  mem_initiated    = false;
+  bool                  cell_initiated   = false;
+  mutable std::mutex    mutex;
 };
 
 } // namespace srsue
diff --git a/srsue/src/phy/prach.cc b/srsue/src/phy/prach.cc
index f227ddf12..8425f7e34 100644
--- a/srsue/src/phy/prach.cc
+++ b/srsue/src/phy/prach.cc
@@ -33,15 +33,6 @@ using namespace srsue;
 void prach::init(uint32_t max_prb)
 {
   std::lock_guard<std::mutex> lock(mutex);
-  for (auto& i : buffer) {
-    for (auto& j : i) {
-      j = srsran_vec_cf_malloc(SRSRAN_PRACH_MAX_LEN);
-      if (!j) {
-        perror("malloc");
-        return;
-      }
-    }
-  }
 
   if (srsran_cfo_init(&cfo_h, SRSRAN_PRACH_MAX_LEN)) {
     ERROR("PRACH: Error initiating CFO");
@@ -50,7 +41,7 @@ void prach::init(uint32_t max_prb)
 
   srsran_cfo_set_tol(&cfo_h, 0);
 
-  signal_buffer = srsran_vec_cf_malloc(MAX_LEN_SF * 30720U);
+  signal_buffer = srsran_vec_cf_malloc(SRSRAN_MAX(MAX_LEN_SF * 30720U, SRSRAN_PRACH_MAX_LEN));
   if (!signal_buffer) {
     perror("malloc");
     return;
@@ -71,12 +62,6 @@ void prach::stop()
     return;
   }
 
-  for (auto& i : buffer) {
-    for (auto& j : i) {
-      free(j);
-    }
-  }
-
   free(signal_buffer);
   srsran_cfo_free(&cfo_h);
   srsran_prach_free(&prach_obj);
@@ -118,7 +103,6 @@ bool prach::set_cell(srsran_cell_t cell_, srsran_prach_cfg_t prach_cfg)
     return false;
   }
 
-  buffer_bitmask.reset();
   len             = prach_obj.N_seq + prach_obj.N_cp;
   transmitted_tti = -1;
   cell_initiated  = true;
@@ -130,22 +114,16 @@ bool prach::set_cell(srsran_cell_t cell_, srsran_prach_cfg_t prach_cfg)
 
 bool prach::generate_buffer(uint32_t f_idx)
 {
-  if (is_buffer_generated(f_idx, preamble_idx)) {
-    return true;
-  }
-
   uint32_t freq_offset = cfg.freq_offset;
   if (cell.frame_type == SRSRAN_TDD) {
     freq_offset = srsran_prach_f_ra_tdd(
         cfg.config_idx, cfg.tdd_config.sf_config, (f_idx / 6) * 10, f_idx % 6, cfg.freq_offset, cell.nof_prb);
   }
-  if (srsran_prach_gen(&prach_obj, preamble_idx, freq_offset, buffer[f_idx][preamble_idx])) {
+  if (srsran_prach_gen(&prach_obj, preamble_idx, freq_offset, signal_buffer)) {
     Error("Generating PRACH preamble %d", preamble_idx);
     return false;
   }
 
-  set_buffer_as_generated(f_idx, preamble_idx);
-
   return true;
 }
 
@@ -239,13 +217,8 @@ cf_t* prach::generate(float cfo, uint32_t* nof_sf, float* target_power)
     return nullptr;
   }
 
-  if (!is_buffer_generated(f_idx, preamble_idx)) {
-    Error("PRACH Buffer not generated: f_idx=%d preamble_idx=%d", f_idx, preamble_idx);
-    return nullptr;
-  }
-
   // Correct CFO before transmission
-  srsran_cfo_correct(&cfo_h, buffer[f_idx][preamble_idx], signal_buffer, cfo / srsran_symbol_sz(cell.nof_prb));
+  srsran_cfo_correct(&cfo_h, signal_buffer, signal_buffer, cfo / srsran_symbol_sz(cell.nof_prb));
 
   // pad guard symbols with zeros
   uint32_t nsf = SRSRAN_CEIL(len, SRSRAN_SF_LEN_PRB(cell.nof_prb));