Allocate PUCCH resources on ConnectionRequest and send ConnectionReject if not available

srsenb/hdr/stack/rrc/rrc_cell_cfg.h

@@ -127,8 +127,9 @@ public:
                             const enb_cell_common_list& enb_common_list);
   ~ue_cell_ded_list();
 
-  ue_cell_ded* add_cell(uint32_t enb_cc_idx);
+  ue_cell_ded* add_cell(uint32_t enb_cc_idx, bool init_pucch = true);
   bool         rem_last_cell();
+  bool         init_pucch_pcell();
   bool         set_cells(const std::vector<uint32_t>& enb_cc_idxs);
 
   ue_cell_ded* get_ue_cc_idx(uint32_t ue_cc_idx) { return (ue_cc_idx < nof_cells()) ? &cell_list[ue_cc_idx] : nullptr; }

srsenb/hdr/stack/rrc/rrc_ue.h

@@ -51,6 +51,9 @@ public:
   void        protocol_failure();
   void        deactivate_bearers() { mac_ctrl.set_radio_bearer_state(mac_lc_ch_cfg_t::IDLE); }
 
+  // Init PUCCH resources for PCell
+  bool init_pucch();
+
   rrc_state_t get_state();
   void        get_metrics(rrc_ue_metrics_t& ue_metrics) const;
 

srsenb/src/stack/rrc/rrc_cell_cfg.cc

@@ -170,7 +170,7 @@ const ue_cell_ded* ue_cell_ded_list::find_cell(uint32_t earfcn, uint32_t pci) co
   return it == cell_list.end() ? nullptr : &(*it);
 }
 
-ue_cell_ded* ue_cell_ded_list::add_cell(uint32_t enb_cc_idx)
+ue_cell_ded* ue_cell_ded_list::add_cell(uint32_t enb_cc_idx, bool init_pucch)
 {
   const enb_cell_common* cell_common = common_list.get_cc_idx(enb_cc_idx);
   if (cell_common == nullptr) {
@@ -193,10 +193,12 @@ ue_cell_ded* ue_cell_ded_list::add_cell(uint32_t enb_cc_idx)
   cell_list.emplace_back(cell_list.size(), *cell_common);
 
   // Allocate CQI, SR, and PUCCH CS resources. If failure, do not add new cell
+  if (init_pucch) {
     if (not alloc_cell_resources(ue_cc_idx)) {
       rem_last_cell();
       return nullptr;
     }
+  }
 
   return &cell_list.back();
 }
@@ -216,6 +218,17 @@ bool ue_cell_ded_list::rem_last_cell()
   return true;
 }
 
+bool ue_cell_ded_list::init_pucch_pcell()
+{
+  if (not alloc_cell_resources(UE_PCELL_CC_IDX)) {
+    dealloc_sr_resources();
+    dealloc_pucch_cs_resources();
+    dealloc_cqi_resources(UE_PCELL_CC_IDX);
+    return false;
+  }
+  return true;
+}
+
 bool ue_cell_ded_list::alloc_cell_resources(uint32_t ue_cc_idx)
 {
   const uint32_t meas_gap_duration = 6;

srsenb/src/stack/rrc/rrc_mobility.cc

@@ -171,9 +171,20 @@ uint16_t rrc::start_ho_ue_resource_alloc(const asn1::s1ap::ho_request_s&
   }
 
   // Register new user in RRC
-  add_user(rnti, ue_cfg);
+  if (add_user(rnti, ue_cfg) != SRSRAN_SUCCESS) {
+    logger.error("Failed to create user");
+    cause.set_radio_network().value = asn1::s1ap::cause_radio_network_opts::no_radio_res_available_in_target_cell;
+    return SRSRAN_INVALID_RNTI;
+  }
   auto it     = users.find(rnti);
   ue*  ue_ptr = it->second.get();
+  if (not ue_ptr->init_pucch()) {
+    rem_user(rnti);
+    logger.warning("Failed to allocate PUCCH resources for rnti=0x%x", rnti);
+    cause.set_radio_network().value = asn1::s1ap::cause_radio_network_opts::no_radio_res_available_in_target_cell;
+    return SRSRAN_INVALID_RNTI;
+  }
+
   // Reset activity timer (Response is not expected)
   ue_ptr->set_activity_timeout(ue::UE_INACTIVITY_TIMEOUT);
   ue_ptr->set_activity(false);

srsenb/src/stack/rrc/rrc_ue.cc

@@ -47,10 +47,16 @@ rrc::ue::ue(rrc* outer_rrc, uint16_t rnti_, const sched_interface::ue_cfg_t& sch
 
 rrc::ue::~ue() {}
 
+bool rrc::ue::init_pucch()
+{
+  // Allocate PUCCH resources for PCell
+  return ue_cell_list.init_pucch_pcell();
+}
+
 int rrc::ue::init()
 {
-  // Allocate cell and PUCCH resources
-  if (ue_cell_list.add_cell(mac_ctrl.get_ue_sched_cfg().supported_cc_list[0].enb_cc_idx) == nullptr) {
+  // Allocate cell (PUCCH resources are not allocated here)
+  if (ue_cell_list.add_cell(mac_ctrl.get_ue_sched_cfg().supported_cc_list[0].enb_cc_idx, false) == nullptr) {
     return SRSRAN_ERROR;
   }
 
@@ -436,6 +442,13 @@ void rrc::ue::handle_rrc_con_req(rrc_conn_request_s* msg)
     return;
   }
 
+  // Allocate PUCCH resources and reject if not available
+  if (not init_pucch()) {
+    parent->logger.warning("Could not allocate PUCCH resources for rnti=0x%x. Sending Connection Reject", rnti);
+    send_connection_reject(procedure_result_code::fail_in_radio_interface_proc);
+    return;
+  }
+
   rrc_conn_request_r8_ies_s* msg_r8 = &msg->crit_exts.rrc_conn_request_r8();
 
   if (msg_r8->ue_id.type() == init_ue_id_c::types::s_tmsi) {