sched: fix pucch res indexing in pucch_allocator

Signed-off-by: Carlo Galiotto <[email protected]>

Author: carlo-gal

lib/scheduler/pucch_scheduling/pucch_allocator_impl.cpp

@@ -1068,9 +1068,6 @@ pucch_harq_ack_grant pucch_allocator_impl::update_format2_grant(pucch_info&
                                                                 sr_nof_bits                  sr_bits_increment,
                                                                 unsigned                     csi_part1_bits_increment)
 {
-  // TODO replace this with value from config.
-  const unsigned PUCCH_FORMAT2_RES_SET_IDX = 1;
-
   // Retrieving the PUCCH resource configuration depends on whether existing grant is for CSI.
   // If so:  (i) the resource indicator is meaningless; (ii) the PUCCH resource configuration is the CSI specific one.
   // If not: (i) the resource indicator is needed; (ii) the PUCCH resource configuration is retrieved from the resource
@@ -1082,29 +1079,23 @@ pucch_harq_ack_grant pucch_allocator_impl::update_format2_grant(pucch_info&
   srsran_sanity_check(not(current_csi_part1_bits > 0 and current_harq_ack_bits == 0 and harq_ack_bits_increment > 0),
                       "PUCCH resource CSI cannot be converted into HARQ-ACK through this function.");
 
-  const int res_indicator = current_csi_part1_bits > 0 and current_harq_ack_bits == 0
-                                ? 0
-                                : resource_manager.fetch_f2_pucch_res_indic(
-                                      sl_tx,
-                                      existing_f2_grant.crnti,
-                                      ue_cell_cfg.cfg_dedicated().ul_config.value().init_ul_bwp.pucch_cfg.value());
-  srsran_sanity_check(res_indicator >= 0,
-                      "The resource indicator for the allocated PUCCH Format 2 grant is expected to be non-negative");
+  const bool use_pucch_f2_csi_res = current_csi_part1_bits > 0 and current_harq_ack_bits == 0;
+
+  const pucch_harq_resource_alloc_record pucch_f2_harq_info =
+      use_pucch_f2_csi_res ? pucch_harq_resource_alloc_record{.pucch_res = nullptr}
+                           : resource_manager.fetch_specific_f2_harq_resource(
+                                 sl_tx,
+                                 existing_f2_grant.crnti,
+                                 ue_cell_cfg.cfg_dedicated().ul_config.value().init_ul_bwp.pucch_cfg.value());
 
   const pucch_resource* res_cfg =
-      current_csi_part1_bits > 0 and current_harq_ack_bits == 0
-          ? resource_manager.fetch_csi_pucch_res_config(sl_tx, existing_f2_grant.crnti, ue_cell_cfg)
-          : &ue_cell_cfg.cfg_dedicated()
-                 .ul_config.value()
-                 .init_ul_bwp.pucch_cfg.value()
-                 .pucch_res_list[ue_cell_cfg.cfg_dedicated()
-                                     .ul_config.value()
-                                     .init_ul_bwp.pucch_cfg.value()
-                                     .pucch_res_set[PUCCH_FORMAT2_RES_SET_IDX]
-                                     .pucch_res_id_list[static_cast<unsigned>(res_indicator)]];
-
-  srsran_sanity_check(res_cfg != nullptr,
-                      "PUCCH resource previously allocated for UCI not found in the PUCCH resource manager.");
+      use_pucch_f2_csi_res ? resource_manager.fetch_csi_pucch_res_config(sl_tx, existing_f2_grant.crnti, ue_cell_cfg)
+                           : pucch_f2_harq_info.pucch_res;
+
+  if (res_cfg == nullptr) {
+    srsran_assertion_failure("PUCCH resource previously allocated for UCI not found in the PUCCH resource manager.");
+    return pucch_harq_ack_grant{.pucch_res_indicator = 0, .pucch_pdu = nullptr};
+  }
 
   // Check if the number of PRBs is sufficient for the number of bits to be acked.
   const float max_pucch_code_rate = to_max_code_rate_float(ue_cell_cfg.cfg_dedicated()
@@ -1142,6 +1133,7 @@ pucch_harq_ack_grant pucch_allocator_impl::update_format2_grant(pucch_info&
   }
 
   logger.debug("ue={:#x}'s UCI mltplxd on existing PUCCH F2 for slot={}", existing_f2_grant.crnti, sl_tx);
+  const unsigned res_indicator = use_pucch_f2_csi_res ? 0U : pucch_f2_harq_info.pucch_res_indicator;
   return pucch_harq_ack_grant{.pucch_res_indicator = static_cast<unsigned>(res_indicator),
                               .pucch_pdu           = &existing_f2_grant};
 }

lib/scheduler/pucch_scheduling/pucch_resource_manager.cpp

@@ -280,6 +280,54 @@ int pucch_resource_manager::fetch_f2_pucch_res_indic(slot_point slot_tx, rnti_t
   return fetch_pucch_res_indic(slot_tx, crnti, pucch_cfg, pucch_format::FORMAT_2);
 }
 
+const pucch_harq_resource_alloc_record
+pucch_resource_manager::fetch_specific_f2_harq_resource(slot_point          slot_harq,
+                                                        rnti_t              crnti,
+                                                        const pucch_config& pucch_cfg)
+{
+  srsran_sanity_check(slot_harq < last_sl_ind + RES_MANAGER_RING_BUFFER_SIZE,
+                      "PUCCH being allocated to far into the future");
+
+  // Get resource list of wanted slot.
+  rnti_pucch_res_id_slot_record& res_counter = get_slot_resource_counter(slot_harq);
+
+  auto& slot_res_array = res_counter.ues_using_pucch_res;
+
+  // Get the span over the array of resources for the specific UE.
+  const auto& ue_res_id_set_for_harq = pucch_cfg.pucch_res_set[PUCCH_HARQ_F2_RES_SET_ID].pucch_res_id_list;
+  unsigned    ue_first_res_id        = ue_res_id_set_for_harq.front();
+  srsran_assert(ue_first_res_id + ue_res_id_set_for_harq.size() <= slot_res_array.size(),
+                "Indexing of PUCCH resource set exceeds the size of the cell resource array");
+  span<resource_tracker> slot_ue_res_array(&slot_res_array[ue_first_res_id], ue_res_id_set_for_harq.size());
+
+  // Check first if the target PUCCH resource (given the CRNTI and usage) exists within the resource tracker.
+  auto* target_ue_resource = std::find_if(
+      slot_ue_res_array.begin(), slot_ue_res_array.end(), [target_rnti = crnti](const resource_tracker res) {
+        return res.rnti == target_rnti and res.resource_usage == pucch_resource_usage::HARQ_F2;
+      });
+
+  const auto& pucch_res_list = pucch_cfg.pucch_res_list;
+
+  // If there is an available resource, try to allocate it.
+  if (target_ue_resource != slot_ue_res_array.end() and
+      static_cast<unsigned>(target_ue_resource - slot_ue_res_array.begin()) <
+          pucch_cfg.pucch_res_set[PUCCH_HARQ_F2_RES_SET_ID].pucch_res_id_list.size()) {
+    // Get the PUCCH resource indicator from the available resource position within the span.
+    const unsigned pucch_res_indicator = static_cast<unsigned>(target_ue_resource - slot_ue_res_array.begin());
+    // Get the PUCCH resource ID from the PUCCH resource indicator and the PUCCH resource set.
+    const unsigned pucch_res_idx_from_list = ue_res_id_set_for_harq[pucch_res_indicator];
+
+    // Search for the PUCCH resource with the correct PUCCH resource ID from the PUCCH resource list.
+    const auto* res_cfg = std::find_if(
+        pucch_res_list.begin(), pucch_res_list.end(), [pucch_res_idx_from_list](const pucch_resource& res) {
+          return res.res_id == pucch_res_idx_from_list;
+        });
+
+    return pucch_harq_resource_alloc_record{.pucch_res = &(*res_cfg), .pucch_res_indicator = pucch_res_indicator};
+  }
+  return pucch_harq_resource_alloc_record{.pucch_res = nullptr};
+}
+
 const pucch_resource* pucch_resource_manager::fetch_csi_pucch_res_config(slot_point                   slot_tx,
                                                                          rnti_t                       crnti,
                                                                          const ue_cell_configuration& ue_cell_cfg)

lib/scheduler/pucch_scheduling/pucch_resource_manager.h

@@ -124,6 +124,12 @@ class pucch_resource_manager
   /// \return PUCCH resource indicator of the resource used allocated to the UE; if UE is not found, returns -1.
   int fetch_f2_pucch_res_indic(slot_point slot_tx, rnti_t crnti, const pucch_config& pucch_cfg);
 
+  /// \brief Returns the configuration of the PUCCH Format 2 resource used for HARQ already allocated to a given RNTI at
+  /// a given slot.
+  /// \return Pointer to the resource configuration allocated to the UE; if UE is not found, returns \c nullptr.
+  const pucch_harq_resource_alloc_record
+  fetch_specific_f2_harq_resource(slot_point slot_harq, rnti_t crnti, const pucch_config& pucch_cfg);
+
   /// \brief Returns the configuration of the PUCCH resource used for CSI (format 2) for a given RNTI at a given slot.
   /// \return Pointer to the resource configuration used allocated to the UE; if UE is not found, returns \c nullptr.
   const pucch_resource*

lib/scheduler/uci_scheduling/uci_allocator_impl.cpp

@@ -208,8 +208,8 @@ void uci_allocator_impl::multiplex_uci_on_pusch(ul_sched_info&                pu
                                                 const ue_cell_configuration&  ue_cell_cfg,
                                                 rnti_t                        crnti)
 {
-  // Note: the UCI bits is capped to the PUCCH Format 2 capacity. When multiplexing UCI to PUSCH, we only "tranfer" the
-  // bits that would have been fit within the PUCCH, not the all the bits that should have been reported.
+  // Note: the UCI bits is capped to the PUCCH Format 2 capacity. When multiplexing UCI to PUSCH, we only "tranfer"
+  // the bits that would have been fit within the PUCCH, not the all the bits that should have been reported.
   // TODO: Check if this approach is correct.
   const pucch_uci_bits pucch_uci = pucch_alloc.remove_ue_uci_from_pucch(slot_alloc, crnti, ue_cell_cfg);