fix sched_dl_cqi method to compute cqi-optimal rbgmask

srsenb/hdr/stack/mac/sched_common.h

@@ -25,6 +25,7 @@ namespace srsenb {
 
 constexpr float    tti_duration_ms = 1;
 constexpr uint32_t NOF_AGGR_LEVEL  = 4;
+constexpr uint32_t MAX_NOF_RBGS    = 25;
 
 /***********************
  *   Helper Types
@@ -85,7 +86,7 @@ public:
 using pdcch_mask_t = srsran::bounded_bitset<sched_interface::max_cce, true>;
 
 //! Bitmask that stores the allocared DL RBGs
-using rbgmask_t = srsran::bounded_bitset<25, true>;
+using rbgmask_t = srsran::bounded_bitset<MAX_NOF_RBGS, true>;
 
 //! Bitmask that stores the allocated UL PRBs
 using prbmask_t = srsran::bounded_bitset<100, true>;

srsenb/hdr/stack/mac/sched_ue_ctrl/sched_dl_cqi.h

@@ -88,6 +88,16 @@ public:
 
   int get_avg_cqi() const { return get_grant_avg_cqi(rbg_interval(0, cell_nof_rbg)); }
 
+  /// Get CQI of RBG
+  int get_rbg_cqi(uint32_t rbg) const
+  {
+    if (not subband_cqi_enabled()) {
+      return static_cast<int>(wb_cqi_avg);
+    }
+    uint32_t sb_idx = rbg_to_sb_index(rbg);
+    return bp_list[get_bp_index(sb_idx)].last_feedback_tti.is_valid() ? subband_cqi[sb_idx] : wb_cqi_avg;
+  }
+
   /// Get average CQI in given RBG interval
   int get_grant_avg_cqi(rbg_interval interv) const
   {
@@ -126,21 +136,12 @@ public:
   }
 
   /// Get CQI-optimal RBG mask
-  rbgmask_t get_optim_rbg_mask(uint32_t req_rbgs) const
+  rbgmask_t get_optim_rbgmask(uint32_t req_rbgs) const
   {
-    req_rbgs = std::min(req_rbgs, cell_nof_rbg);
-    rbgmask_t mask(cell_nof_rbg);
-    if (not subband_cqi_enabled()) {
-      mask.fill(0, req_rbgs);
-      return mask;
-    }
-    srsran::bounded_vector<float, max_nof_subbands> sorted_cqis = subband_cqi;
-    std::partial_sort(sorted_cqis.begin(), sorted_cqis.begin() + req_rbgs, sorted_cqis.end());
-    for (uint32_t i = 0; i < req_rbgs; ++i) {
-      mask.set(i);
-    }
-    return mask;
+    rbgmask_t rbgmask(cell_nof_rbg);
+    return get_optim_rbgmask(rbgmask, req_rbgs);
   }
+  rbgmask_t get_optim_rbgmask(const rbgmask_t& dl_mask, uint32_t req_rbgs) const;
 
   /// TS 36.321, 7.2.2 - Parameter N
   uint32_t nof_subbands() const { return subband_cqi.size(); }

srsenb/hdr/stack/mac/schedulers/sched_base.h

@@ -43,7 +43,7 @@ rbg_interval find_empty_rbg_interval(uint32_t max_nof_rbgs, const rbgmask_t& cur
  * @param current_mask bitmask of occupied RBGs, where to search for available RBGs
  * @return bitmask of found RBGs. If a valid mask wasn't found, bitmask::size() == 0
  */
-rbgmask_t compute_rbgmask_greedy(uint32_t max_nof_rbgs, bool is_contiguous, const rbgmask_t& current_mask);
+rbgmask_t find_available_rbgmask(uint32_t max_nof_rbgs, bool is_contiguous, const rbgmask_t& current_mask);
 
 /**
  * Finds a range of L contiguous PRBs that are empty

srsenb/src/stack/mac/CMakeLists.txt

@@ -9,7 +9,7 @@
 add_subdirectory(schedulers)
 
 set(SOURCES mac.cc ue.cc sched.cc sched_carrier.cc sched_grid.cc sched_ue_ctrl/sched_harq.cc sched_ue.cc
-        sched_ue_ctrl/sched_lch.cc sched_ue_ctrl/sched_ue_cell.cc sched_phy_ch/sf_cch_allocator.cc sched_phy_ch/sched_dci.cc sched_helpers.cc)
+        sched_ue_ctrl/sched_lch.cc sched_ue_ctrl/sched_ue_cell.cc sched_ue_ctrl/sched_dl_cqi.cc sched_phy_ch/sf_cch_allocator.cc sched_phy_ch/sched_dci.cc sched_helpers.cc)
 add_library(srsenb_mac STATIC ${SOURCES} $<TARGET_OBJECTS:mac_schedulers>)
 
 set(SOURCES mac_nr.cc)

srsenb/src/stack/mac/sched_ue_ctrl/sched_dl_cqi.cc

@@ -0,0 +1,46 @@
+/**
+ *
+ * \section COPYRIGHT
+ *
+ * Copyright 2013-2021 Software Radio Systems Limited
+ *
+ * By using this file, you agree to the terms and conditions set
+ * forth in the LICENSE file which can be found at the top level of
+ * the distribution.
+ *
+ */
+
+#include "srsenb/hdr/stack/mac/sched_ue_ctrl/sched_dl_cqi.h"
+#include "srsenb/hdr/stack/mac/schedulers/sched_base.h"
+
+using namespace srsenb;
+
+rbgmask_t sched_dl_cqi::get_optim_rbgmask(const rbgmask_t& dl_mask, uint32_t req_rbgs) const
+{
+  req_rbgs = std::min(req_rbgs, cell_nof_rbg);
+  if (not subband_cqi_enabled()) {
+    // in case of wideband, just find any available RBGs
+    return find_available_rbgmask(req_rbgs, false, dl_mask);
+  }
+
+  rbgmask_t emptymask = ~dl_mask;
+  if (emptymask.none() or req_rbgs >= emptymask.size() or emptymask.count() <= req_rbgs) {
+    return emptymask;
+  }
+
+  srsran::bounded_vector<uint32_t, MAX_NOF_RBGS> sorted_cqi_pos;
+  srsran::bounded_vector<uint32_t, MAX_NOF_RBGS> sorted_cqis;
+  for (int pos = emptymask.find_lowest(0, emptymask.size(), true); pos >= 0;
+       pos     = emptymask.find_lowest(pos + 1, emptymask.size(), true)) {
+    sorted_cqis.push_back(get_rbg_cqi(pos));
+    sorted_cqi_pos.push_back(pos);
+  }
+  std::stable_sort(sorted_cqi_pos.begin(), sorted_cqi_pos.end(), [&sorted_cqis](uint32_t lhs, uint32_t rhs) {
+    return sorted_cqis[lhs] > sorted_cqis[rhs];
+  });
+  for (size_t i = req_rbgs; i < sorted_cqi_pos.size(); ++i) {
+    emptymask.set(sorted_cqi_pos[i], false);
+  }
+
+  return emptymask;
+}

srsenb/src/stack/mac/schedulers/sched_base.cc

@@ -49,11 +49,16 @@ RBInterval find_contiguous_interval(const RBMask& in_mask, uint32_t max_size)
  *    DL Helper methods
  ***************************/
 
-rbgmask_t find_available_rb_mask(const rbgmask_t& in_mask, uint32_t max_size)
+rbgmask_t find_available_rbgmask(const rbgmask_t& in_mask, uint32_t max_size)
 {
   // 1's for free RBs
   rbgmask_t localmask = ~(in_mask);
 
+  if (max_size >= localmask.size() or max_size >= localmask.count()) {
+    // shortcut in case rbg count < max_size
+    return localmask;
+  }
+
   uint32_t i = 0, nof_alloc = 0;
   for (; i < localmask.size() and nof_alloc < max_size; ++i) {
     if (localmask.test(i)) {
@@ -69,7 +74,7 @@ rbg_interval find_empty_rbg_interval(uint32_t max_nof_rbgs, const rbgmask_t& cur
   return find_contiguous_interval(current_mask, max_nof_rbgs);
 }
 
-rbgmask_t compute_rbgmask_greedy(uint32_t max_nof_rbgs, bool is_contiguous, const rbgmask_t& current_mask)
+rbgmask_t find_available_rbgmask(uint32_t max_nof_rbgs, bool is_contiguous, const rbgmask_t& current_mask)
 {
   // Allocate enough RBs that accommodate pending data
   rbgmask_t newtx_mask(current_mask.size());
@@ -77,7 +82,7 @@ rbgmask_t compute_rbgmask_greedy(uint32_t max_nof_rbgs, bool is_contiguous, cons
     rbg_interval interv = find_contiguous_interval(current_mask, max_nof_rbgs);
     newtx_mask.fill(interv.start(), interv.stop());
   } else {
-    newtx_mask = find_available_rb_mask(current_mask, max_nof_rbgs);
+    newtx_mask = find_available_rbgmask(current_mask, max_nof_rbgs);
   }
   return newtx_mask;
 }
@@ -128,7 +133,7 @@ alloc_result try_dl_retx_alloc(sf_sched& tti_sched, sched_ue& ue, const dl_harq_
   // If previous mask does not fit, find another with exact same number of rbgs
   size_t nof_rbg             = retx_mask.count();
   bool   is_contiguous_alloc = ue.get_dci_format() == SRSRAN_DCI_FORMAT1A;
-  retx_mask                  = compute_rbgmask_greedy(nof_rbg, is_contiguous_alloc, tti_sched.get_dl_mask());
+  retx_mask                  = find_available_rbgmask(nof_rbg, is_contiguous_alloc, tti_sched.get_dl_mask());
   if (retx_mask.count() == nof_rbg) {
     return tti_sched.alloc_dl_user(&ue, retx_mask, h.get_id());
   }
@@ -155,7 +160,7 @@ alloc_result try_dl_newtx_alloc_greedy(sf_sched& tti_sched, sched_ue& ue, const
 
   // Find RBG mask that accommodates pending data
   bool      is_contiguous_alloc = ue.get_dci_format() == SRSRAN_DCI_FORMAT1A;
-  rbgmask_t newtxmask           = compute_rbgmask_greedy(req_rbgs.stop(), is_contiguous_alloc, current_mask);
+  rbgmask_t newtxmask           = find_available_rbgmask(req_rbgs.stop(), is_contiguous_alloc, current_mask);
   if (newtxmask.none() or newtxmask.count() < req_rbgs.start()) {
     return alloc_result::no_sch_space;
   }

srsenb/test/mac/sched_cqi_test.cc

@@ -45,7 +45,7 @@ void test_sched_cqi_one_subband_cqi()
   TESTASSERT(ue_cqi.get_grant_avg_cqi(mask) > 0 and ue_cqi.get_grant_avg_cqi(mask) < 5);
 
   // TEST: Get optimal RBG mask in terms of CQI
-  mask = ue_cqi.get_optim_rbg_mask(5);
+  mask = ue_cqi.get_optim_rbgmask(5);
   TESTASSERT(mask.count() == 5);
   for (uint32_t i = 0; i < 5; ++i) {
     TESTASSERT(mask.test(i) > 0);
@@ -73,7 +73,7 @@ void test_sched_cqi_wideband_cqi()
   TESTASSERT(ue_cqi.get_grant_avg_cqi(mask) == 5);
 
   // TEST: Get optimal RBG mask in terms of CQI
-  mask = ue_cqi.get_optim_rbg_mask(5);
+  mask = ue_cqi.get_optim_rbgmask(5);
   TESTASSERT(mask.count() == 5);
   for (uint32_t i = 0; i < 5; ++i) {
     TESTASSERT(mask.test(i) > 0);