Remove SNR threshold based link failure detection

lib/include/srslte/interfaces/enb_interfaces.h

@@ -182,10 +182,6 @@ public:
   virtual int  get_mch_sched(uint32_t tti, bool is_mcch, dl_sched_list_t& dl_sched_res) = 0;
   virtual int  get_ul_sched(uint32_t tti, ul_sched_list_t& ul_sched_res)                = 0;
   virtual void set_sched_dl_tti_mask(uint8_t* tti_mask, uint32_t nof_sfs)               = 0;
-
-  // Radio-Link status
-  virtual void rl_failure(uint16_t rnti) = 0;
-  virtual void rl_ok(uint16_t rnti)      = 0;
 };
 
 /* Interface MAC -> PHY */
@@ -410,7 +406,6 @@ class rrc_interface_mac
 {
 public:
   /* Radio Link failure */
-  virtual void rl_failure(uint16_t rnti)                                             = 0;
   virtual void add_user(uint16_t rnti, const sched_interface::ue_cfg_t& init_ue_cfg) = 0;
   virtual void upd_user(uint16_t new_rnti, uint16_t old_rnti)                        = 0;
   virtual void set_activity_user(uint16_t rnti)                                      = 0;
@@ -544,7 +539,6 @@ typedef struct {
 typedef struct {
   uint32_t                      nof_prb; ///< Needed to dimension MAC softbuffers for all cells
   sched_interface::sched_args_t sched;
-  int                           link_failure_nof_err;
   int                           nr_tb_size = -1;
 } mac_args_t;
 

lib/src/phy/enb/enb_dl.c

@@ -531,7 +531,11 @@ enb_dl_get_ack_fdd_pcell_skip_drx(const srslte_uci_value_t* uci_value, srslte_pd
     for (uint32_t tb = 0; tb < nof_tb; tb++) {
       // Check that TB was transmitted
       if (pdsch_ack->cc[0].m[0].value[tb] != 2) {
-        pdsch_ack->cc[0].m[0].value[tb] = uci_value->ack.ack_value[ack_idx++];
+        if (uci_value->ack.valid) {
+          pdsch_ack->cc[0].m[0].value[tb] = uci_value->ack.ack_value[ack_idx++];
+        } else {
+          pdsch_ack->cc[0].m[0].value[tb] = 0;
+        }
       }
     }
   }
@@ -545,7 +549,11 @@ enb_dl_get_ack_fdd_all_keep_drx(const srslte_uci_value_t* uci_value, srslte_pdsc
       for (uint32_t tb = 0; tb < nof_tb; tb++) {
         // Check that TB was transmitted
         if (pdsch_ack->cc[cc_idx].m[0].value[tb] != 2) {
-          pdsch_ack->cc[cc_idx].m[0].value[tb] = uci_value->ack.ack_value[cc_idx * nof_tb + tb];
+          if (uci_value->ack.valid) {
+            pdsch_ack->cc[cc_idx].m[0].value[tb] = uci_value->ack.ack_value[cc_idx * nof_tb + tb];
+          } else {
+            pdsch_ack->cc[cc_idx].m[0].value[tb] = 0;
+          }
         }
       }
     }

srsenb/enb.conf.example

@@ -277,8 +277,6 @@ pusch_max_mcs    = 16
 # metrics_csv_filename: File path to use for CSV metrics.
 # pregenerate_signals:  Pregenerate uplink signals after attach. Improves CPU performance.
 # tx_amplitude:         Transmit amplitude factor (set 0-1 to reduce PAPR)
-# link_failure_nof_err: Number of PUSCH failures after which a radio-link failure is triggered. 
-#                       a link failure is when SNR<0 and CRC=KO
 # max_prach_offset_us:  Maximum allowed RACH offset (in us)
 # eea_pref_list:        Ordered preference list for the selection of encryption algorithm (EEA) (default: EEA0, EEA2, EEA1).
 # eia_pref_list:        Ordered preference list for the selection of integrity algorithm (EIA) (default: EIA2, EIA1, EIA0).
@@ -293,7 +291,6 @@ pusch_max_mcs    = 16
 #metrics_csv_filename = /tmp/enb_metrics.csv
 #pregenerate_signals  = false
 #tx_amplitude         = 0.6
-#link_failure_nof_err = 50
 #rrc_inactivity_timer = 60000
 #max_prach_offset_us  = 30
 #eea_pref_list = EEA0, EEA2, EEA1

srsenb/hdr/stack/enb_stack_lte.h

@@ -101,9 +101,6 @@ public:
   {
     mac.set_sched_dl_tti_mask(tti_mask, nof_sfs);
   }
-  // Radio-Link status
-  void rl_failure(uint16_t rnti) final { mac.rl_failure(rnti); }
-  void rl_ok(uint16_t rnti) final { mac.rl_ok(rnti); }
   void tti_clock() override;
 
   /* STACK-S1AP interface*/

srsenb/hdr/stack/mac/mac.h

@@ -74,8 +74,6 @@ public:
     scheduler.set_dl_tti_mask(tti_mask, nof_sfs);
   }
   void build_mch_sched(uint32_t tbs);
-  void rl_failure(uint16_t rnti) override;
-  void rl_ok(uint16_t rnti) override;
 
   /******** Interface from RRC (RRC -> MAC) ****************/
   /* Provides cell configuration including SIB periodicity, etc. */

srsenb/hdr/stack/mac/ue.h

@@ -84,9 +84,6 @@ public:
   void     push_pdu(const uint32_t ue_cc_idx, const uint32_t tti, uint32_t len);
   void     deallocate_pdu(const uint32_t ue_cc_idx, const uint32_t tti);
 
-  uint32_t rl_failure();
-  void     rl_failure_reset();
-
   void set_lcg(uint32_t lcid, uint32_t lcg);
 
   void metrics_read(srsenb::mac_metrics_t* metrics);

srsenb/hdr/stack/rrc/rrc.h

@@ -69,7 +69,6 @@ public:
   void tti_clock();
 
   // rrc_interface_mac
-  void     rl_failure(uint16_t rnti) override;
   void     add_user(uint16_t rnti, const sched_interface::ue_cfg_t& init_ue_cfg) override;
   void     upd_user(uint16_t new_rnti, uint16_t old_rnti) override;
   void     set_activity_user(uint16_t rnti) override;
@@ -142,7 +141,6 @@ private:
   std::map<uint32_t, asn1::rrc::paging_record_s> pending_paging;
 
   void     process_release_complete(uint16_t rnti);
-  void     process_rl_failure(uint16_t rnti);
   void     rem_user(uint16_t rnti);
   uint32_t generate_sibs();
   void     configure_mbsfn_sibs(asn1::rrc::sib_type2_s* sib2, asn1::rrc::sib_type13_r9_s* sib13);
@@ -162,7 +160,6 @@ private:
   const static uint32_t LCID_EXIT     = 0xffff0000;
   const static uint32_t LCID_REM_USER = 0xffff0001;
   const static uint32_t LCID_REL_USER = 0xffff0002;
-  const static uint32_t LCID_RLF_USER = 0xffff0003;
   const static uint32_t LCID_ACT_USER = 0xffff0004;
 
   bool                         running         = false;

srsenb/hdr/stack/rrc/rrc_ue.h

@@ -47,8 +47,6 @@ public:
   void        set_activity();
   void        activity_timer_expired();
 
-  uint32_t rl_failure();
-
   rrc_state_t get_state();
 
   void send_connection_setup();

srsenb/src/main.cc

@@ -184,7 +184,6 @@ void parse_args(all_args_t* args, int argc, char* argv[])
     ("expert.pusch_meas_evm", bpo::value<bool>(&args->phy.pusch_meas_evm)->default_value(false), "Enable/Disable PUSCH EVM measure")
     ("expert.tx_amplitude", bpo::value<float>(&args->phy.tx_amplitude)->default_value(0.6), "Transmit amplitude factor")
     ("expert.nof_phy_threads", bpo::value<int>(&args->phy.nof_phy_threads)->default_value(3), "Number of PHY threads")
-    ("expert.link_failure_nof_err", bpo::value<int>(&args->stack.mac.link_failure_nof_err)->default_value(100), "Number of PUSCH failures after which a radio-link failure is triggered")
     ("expert.max_prach_offset_us", bpo::value<float>(&args->phy.max_prach_offset_us)->default_value(30), "Maximum allowed RACH offset (in us)")
     ("expert.equalizer_mode", bpo::value<string>(&args->phy.equalizer_mode)->default_value("mmse"), "Equalizer mode")
     ("expert.estimator_fil_w", bpo::value<float>(&args->phy.estimator_fil_w)->default_value(0.1), "Chooses the coefficients for the 3-tap channel estimator centered filter.")

srsenb/src/phy/cc_worker.cc

@@ -335,19 +335,15 @@ void cc_worker::decode_pusch_rnti(stack_interface_phy_lte::ul_sched_grant_t& ul_
     phy->stack->snr_info(ul_sf.tti, rnti, cc_idx, snr_db);
 
     if (ul_grant.dci.tb.rv == 0) {
-      if (!pusch_res.crc) {
+      // Notify MAC of Time Alignment only if it enabled and valid measurement, ignore value otherwise
-        Debug("PUSCH: Radio-Link failure snr=%.1f dB\n", snr_db);
+      if (ul_cfg.pusch.meas_ta_en and not std::isnan(enb_ul.chest_res.ta_us) and
-        phy->stack->rl_failure(rnti);
+          not std::isinf(enb_ul.chest_res.ta_us)) {
-      } else {
+        phy->stack->ta_info(ul_sf.tti, rnti, enb_ul.chest_res.ta_us);
-        phy->stack->rl_ok(rnti);
-
-        // Notify MAC of Time Alignment only if it enabled and valid measurement, ignore value otherwise
-        if (ul_cfg.pusch.meas_ta_en and not std::isnan(enb_ul.chest_res.ta_us) and
-            not std::isinf(enb_ul.chest_res.ta_us)) {
-          phy->stack->ta_info(ul_sf.tti, rnti, enb_ul.chest_res.ta_us);
-        }
       }
     }
+    pusch_res.uci.ack.valid = true;
+  } else {
+    pusch_res.uci.ack.valid = false;
   }
 
   // Send UCI data to MAC
@@ -408,16 +404,6 @@ int cc_worker::decode_pucch()
           return SRSLTE_ERROR;
         }
 
-        // Notify MAC of RL status (skip SR subframes)
-        if (!ul_cfg.pucch.uci_cfg.is_scheduling_request_tti) {
-          if (pucch_res.correlation < PUCCH_RL_CORR_TH) {
-            Debug("PUCCH: Radio-Link failure corr=%.1f\n", pucch_res.correlation);
-            phy->stack->rl_failure(rnti);
-          } else {
-            phy->stack->rl_ok(rnti);
-          }
-        }
-
         // Send UCI data to MAC
         phy->ue_db.send_uci_data(tti_rx, rnti, cc_idx, ul_cfg.pucch.uci_cfg, pucch_res.uci_data);
 

srsenb/src/stack/mac/mac.cc

@@ -293,31 +293,6 @@ void mac::get_metrics(mac_metrics_t metrics[ENB_METRICS_MAX_USERS])
  *
  *******************************************************/
 
-void mac::rl_failure(uint16_t rnti)
-{
-  srslte::rwlock_read_guard lock(rwlock);
-  if (ue_db.count(rnti)) {
-    uint32_t nof_fails = ue_db[rnti]->rl_failure();
-    if (nof_fails >= (uint32_t)args.link_failure_nof_err && args.link_failure_nof_err > 0) {
-      Info("Detected Uplink failure for rnti=0x%x\n", rnti);
-      rrc_h->rl_failure(rnti);
-      ue_db[rnti]->rl_failure_reset();
-    }
-  } else {
-    Error("User rnti=0x%x not found\n", rnti);
-  }
-}
-
-void mac::rl_ok(uint16_t rnti)
-{
-  srslte::rwlock_read_guard lock(rwlock);
-  if (ue_db.count(rnti)) {
-    ue_db[rnti]->rl_failure_reset();
-  } else {
-    Error("User rnti=0x%x not found\n", rnti);
-  }
-}
-
 int mac::ack_info(uint32_t tti, uint16_t rnti, uint32_t enb_cc_idx, uint32_t tb_idx, bool ack)
 {
   srslte::rwlock_read_guard lock(rwlock);
@@ -329,7 +304,7 @@ int mac::ack_info(uint32_t tti, uint16_t rnti, uint32_t enb_cc_idx, uint32_t tb_
     if (ack) {
       if (nof_bytes > 64) { // do not count RLC status messages only
         rrc_h->set_activity_user(rnti);
-        log_h->debug("DL activity rnti=0x%x, n_bytes=%d\n", rnti, nof_bytes);
+        log_h->info("DL activity rnti=0x%x, n_bytes=%d\n", rnti, nof_bytes);
       }
     }
   }

srsenb/src/stack/mac/ue.cc

@@ -158,17 +158,6 @@ void ue::start_pcap(srslte::mac_pcap* pcap_)
   pcap = pcap_;
 }
 
-uint32_t ue::rl_failure()
-{
-  nof_failures++;
-  return nof_failures;
-}
-
-void ue::rl_failure_reset()
-{
-  nof_failures = 0;
-}
-
 void ue::set_lcg(uint32_t lcid, uint32_t lcg)
 {
   // find and remove if already exists

srsenb/src/stack/rrc/rrc.cc

@@ -122,12 +122,6 @@ uint8_t* rrc::read_pdu_bcch_dlsch(const uint8_t cc_idx, const uint32_t sib_index
   return nullptr;
 }
 
-void rrc::rl_failure(uint16_t rnti)
-{
-  rrc_pdu p = {rnti, LCID_RLF_USER, nullptr};
-  rx_pdu_queue.push(std::move(p));
-}
-
 void rrc::set_activity_user(uint16_t rnti)
 {
   rrc_pdu p = {rnti, LCID_ACT_USER, nullptr};
@@ -503,31 +497,6 @@ void rrc::parse_ul_dcch(uint16_t rnti, uint32_t lcid, srslte::unique_byte_buffer
   }
 }
 
-///< User mutex must be hold by caller
-void rrc::process_rl_failure(uint16_t rnti)
-{
-  auto user_it = users.find(rnti);
-  if (user_it != users.end()) {
-    uint32_t n_rfl = user_it->second->rl_failure();
-    if (n_rfl == 1) {
-      rrc_log->info("Radio-Link failure detected rnti=0x%x\n", rnti);
-      if (s1ap->user_exists(rnti)) {
-        if (!s1ap->user_release(rnti, asn1::s1ap::cause_radio_network_opts::radio_conn_with_ue_lost)) {
-          rrc_log->info("Removing rnti=0x%x\n", rnti);
-        }
-      } else {
-        rrc_log->warning("User rnti=0x%x context not existing in S1AP. Removing user\n", rnti);
-        // Remove user from separate thread to wait to close all resources
-        rem_user_thread(rnti);
-      }
-    } else {
-      rrc_log->info("%d Radio-Link failure detected rnti=0x%x\n", n_rfl, rnti);
-    }
-  } else {
-    rrc_log->error("Radio-Link failure detected for unknown rnti=0x%x\n", rnti);
-  }
-}
-
 ///< User mutex must be hold by caller
 void rrc::process_release_complete(uint16_t rnti)
 {
@@ -788,9 +757,6 @@ void rrc::tti_clock()
       case LCID_REL_USER:
         process_release_complete(p.rnti);
         break;
-      case LCID_RLF_USER:
-        process_rl_failure(p.rnti);
-        break;
       case LCID_ACT_USER:
         user_it->second->set_activity();
         break;

srsenb/src/stack/rrc/rrc_ue.cc

@@ -72,12 +72,6 @@ rrc_state_t rrc::ue::get_state()
   return state;
 }
 
-uint32_t rrc::ue::rl_failure()
-{
-  rlf_cnt++;
-  return rlf_cnt;
-}
-
 void rrc::ue::set_activity()
 {
   // re-start activity timer with current timeout value

srsenb/test/phy/enb_phy_test.cc

@@ -291,8 +291,6 @@ private:
   CALLBACK(get_mch_sched);
   CALLBACK(get_ul_sched);
   CALLBACK(set_sched_dl_tti_mask);
-  CALLBACK(rl_failure);
-  CALLBACK(rl_ok);
   CALLBACK(tti_clock);
 
   typedef struct {
@@ -679,8 +677,6 @@ public:
     return SRSLTE_SUCCESS;
   }
   void set_sched_dl_tti_mask(uint8_t* tti_mask, uint32_t nof_sfs) override { notify_set_sched_dl_tti_mask(); }
-  void rl_failure(uint16_t rnti) override { notify_rl_failure(); }
-  void rl_ok(uint16_t rnti) override { notify_rl_ok(); }
   void tti_clock() override { notify_tti_clock(); }
   int  run_tti(bool enable_assert)
   {
@@ -1283,12 +1279,6 @@ public:
   {
     int ret = SRSLTE_SUCCESS;
 
-    // If no assertion enabled, clear radio link failure to avoid errors in cell transitions
-    if (change_state != change_state_assert) {
-      stack->clear_rl_failure();
-    }
-
-    TESTASSERT(not stack->get_received_rl_failure());
     TESTASSERT(ue_phy->run_tti() >= SRSLTE_SUCCESS);
     TESTASSERT(stack->run_tti(change_state == change_state_assert) >= SRSLTE_SUCCESS);