ue,mac,ra: fix contention resolution procedure

Author: pgawlowicz

srsue/hdr/stack/mac_nr/demux_nr.h

@@ -20,6 +20,12 @@
 
 namespace srsue {
 
+class mac_nr_interface_demux
+{
+public:
+  virtual bool received_contention_id(uint64_t id) = 0;
+};
+
 /**
  * @brief Logical Channel Demultiplexing and MAC CE dissassemble according to TS 38.321
  *
@@ -36,25 +42,26 @@ class demux_nr : public demux_interface_harq_nr
   demux_nr(srslog::basic_logger& logger_);
   ~demux_nr();
 
-  int32_t init(rlc_interface_mac* rlc_, phy_interface_mac_nr* phy_);
+  int32_t init(rlc_interface_mac* rlc_, phy_interface_mac_nr* phy_, mac_nr_interface_demux* mac_);
 
   void process_pdus(); /// Called by MAC to process received PDUs
 
   // HARQ interface
-  void     push_bcch(srsran::unique_byte_buffer_t pdu);
-  void     push_pdu(srsran::unique_byte_buffer_t pdu, uint32_t tti);
-  void     push_pdu_temp_crnti(srsran::unique_byte_buffer_t pdu, uint32_t tti);
-  uint64_t get_received_crueid();
+  void push_bcch(srsran::unique_byte_buffer_t pdu);
+  void push_pdu(srsran::unique_byte_buffer_t pdu, uint32_t tti);
+  void push_pdu_temp_crnti(srsran::unique_byte_buffer_t pdu, uint32_t tti);
+  bool get_uecrid_successful();
 
 private:
   // internal helpers
   void handle_pdu(srsran::mac_sch_pdu_nr& pdu_buffer, srsran::unique_byte_buffer_t pdu);
 
-  srslog::basic_logger& logger;
-  rlc_interface_mac*    rlc = nullptr;
-  phy_interface_mac_nr* phy = nullptr;
+  srslog::basic_logger&   logger;
+  rlc_interface_mac*      rlc = nullptr;
+  phy_interface_mac_nr*   phy = nullptr;
+  mac_nr_interface_demux* mac = nullptr;
 
-  uint64_t received_crueid = 0;
+  bool is_uecrid_successful = false;
 
   ///< currently only DCH & BCH PDUs supported (add PCH, etc)
   srsran::block_queue<srsran::unique_byte_buffer_t> pdu_queue;

srsue/hdr/stack/mac_nr/mac_nr.h

@@ -39,7 +39,8 @@ class mac_nr final : public mac_interface_phy_nr,
                      public mac_interface_proc_ra_nr,
                      public mac_interface_sr_nr,
                      public mac_interface_mux_nr,
-                     public mac_interface_harq_nr
+                     public mac_interface_harq_nr,
+                     public mac_nr_interface_demux
 {
 public:
   mac_nr(srsran::ext_task_sched_handle task_sched_);
@@ -88,7 +89,6 @@ class mac_nr final : public mac_interface_phy_nr,
   void start_ra_procedure();
 
   /// Interface for internal procedures (RA, MUX, HARQ)
-  bool     received_contention_id(uint64_t rx_contention_id);
   uint16_t get_crnti();
   uint16_t get_temp_crnti();
   uint16_t get_csrnti() { return SRSRAN_INVALID_RNTI; }; // SPS not supported
@@ -102,6 +102,9 @@ class mac_nr final : public mac_interface_phy_nr,
   srsran::mac_sch_subpdu_nr::lcg_bsr_t generate_sbsr();
   void                                 set_padding_bytes(uint32_t nof_bytes);
 
+  /// Interface for DEMUX
+  bool received_contention_id(uint64_t rx_contention_id);
+
   void msg3_flush() { mux.msg3_flush(); }
   bool msg3_is_transmitted() { return mux.msg3_is_transmitted(); }
   void msg3_prepare() { mux.msg3_prepare(); }

srsue/hdr/stack/mac_nr/mac_nr_interfaces.h

@@ -24,8 +24,8 @@ class mac_interface_proc_ra_nr
 {
 public:
   // Functions for identity handling, e.g., contention id and c-rnti
-  virtual uint16_t get_crnti()                = 0;
-  virtual bool     set_crnti(uint16_t c_rnti) = 0;
+  virtual uint16_t get_crnti()                     = 0;
+  virtual bool     set_crnti(uint16_t c_rnti)      = 0;
   virtual void     set_temp_crnti(uint16_t c_rnti) = 0;
   virtual void     set_crnti_to_temp()             = 0;
 
@@ -81,9 +81,6 @@ class mac_interface_harq_nr
   // MAC also provides Temp C-RNTI (through RA proc)
   virtual uint16_t get_temp_crnti() = 0;
 
-  // HARQ can query MAC for current C-RNTI
-  virtual bool received_contention_id(uint64_t rx_contention_id) = 0;
-
   // MAC provides the Currently Scheduled RNTI (for SPS)
   virtual uint16_t get_csrnti() = 0;
 };
@@ -95,10 +92,10 @@ class demux_interface_harq_nr
 {
 public:
   /// Inform demux unit about a newly decoded TB.
-  virtual void     push_bcch(srsran::unique_byte_buffer_t pdu)                         = 0;
-  virtual void     push_pdu(srsran::unique_byte_buffer_t pdu, uint32_t tti)            = 0;
-  virtual void     push_pdu_temp_crnti(srsran::unique_byte_buffer_t pdu, uint32_t tti) = 0;
-  virtual uint64_t get_received_crueid()                                               = 0;
+  virtual void push_bcch(srsran::unique_byte_buffer_t pdu)                         = 0;
+  virtual void push_pdu(srsran::unique_byte_buffer_t pdu, uint32_t tti)            = 0;
+  virtual void push_pdu_temp_crnti(srsran::unique_byte_buffer_t pdu, uint32_t tti) = 0;
+  virtual bool get_uecrid_successful()                                             = 0;
 };
 
 } // namespace srsue

srsue/hdr/stack/mac_nr/proc_ra_nr.h

@@ -113,7 +113,7 @@ class proc_ra_nr
   void ra_resource_selection();
   void ra_preamble_transmission();
   void ra_response_reception(const mac_interface_phy_nr::tb_action_dl_result_t& tb);
-  void ra_contention_resolution(bool received_con_res_matches_ue_id);
+  void ra_contention_resolution(bool is_successful, bool is_ul_grant);
   void ra_completion();
   void ra_error();
 };

srsue/src/stack/mac_nr/demux_nr.cc

@@ -21,16 +21,17 @@ demux_nr::demux_nr(srslog::basic_logger& logger_) : logger(logger_) {}
 
 demux_nr::~demux_nr() {}
 
-int32_t demux_nr::init(rlc_interface_mac* rlc_, phy_interface_mac_nr* phy_)
+int32_t demux_nr::init(rlc_interface_mac* rlc_, phy_interface_mac_nr* phy_, mac_nr_interface_demux* mac_)
 {
   rlc = rlc_;
   phy = phy_;
+  mac = mac_;
   return SRSRAN_SUCCESS;
 }
 
-uint64_t demux_nr::get_received_crueid()
+bool demux_nr::get_uecrid_successful()
 {
-  return received_crueid;
+  return is_uecrid_successful;
 }
 
 // Enqueues PDU and returns quickly
@@ -55,7 +56,7 @@ void demux_nr::push_bcch(srsran::unique_byte_buffer_t pdu)
  */
 void demux_nr::push_pdu_temp_crnti(srsran::unique_byte_buffer_t pdu, uint32_t tti)
 {
-  received_crueid = 0;
+  is_uecrid_successful = false;
   handle_pdu(rx_pdu_tcrnti, std::move(pdu));
 }
 
@@ -90,6 +91,7 @@ void demux_nr::handle_pdu(srsran::mac_sch_pdu_nr& pdu_buffer, srsran::unique_byt
     logger.info("%s", srsran::to_c_str(str_buffer));
   }
 
+  bool con_res_rxed = false;
   for (uint32_t i = 0; i < pdu_buffer.get_num_subpdus(); ++i) {
     srsran::mac_sch_subpdu_nr subpdu = pdu_buffer.get_subpdu(i);
     logger.debug("Handling subPDU %d/%d: rnti=0x%x lcid=%d, sdu_len=%d",
@@ -99,7 +101,7 @@ void demux_nr::handle_pdu(srsran::mac_sch_pdu_nr& pdu_buffer, srsran::unique_byt
                  subpdu.get_lcid(),
                  subpdu.get_sdu_length());
 
-    // Handle Timing Advance CE
+    // Handle Contention Resolution UE ID and Timing Advance CE
     switch (subpdu.get_lcid()) {
       case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::DRX_CMD:
         logger.info("DRX CE not implemented.");
@@ -109,12 +111,17 @@ void demux_nr::handle_pdu(srsran::mac_sch_pdu_nr& pdu_buffer, srsran::unique_byt
         phy->set_timeadv(0, subpdu.get_ta().ta_command);
         break;
       case srsran::mac_sch_subpdu_nr::nr_lcid_sch_t::CON_RES_ID:
-        received_crueid = subpdu.get_ue_con_res_id_ce_packed();
+        con_res_rxed = true;
         logger.info("Received Contention Resolution ID 0x%lx", subpdu.get_ue_con_res_id_ce_packed());
+        if (!is_uecrid_successful) {
+          is_uecrid_successful = mac->received_contention_id(subpdu.get_ue_con_res_id_ce_packed());
+        }
         break;
       default:
-        if (subpdu.is_sdu()) {
-          rlc->write_pdu(subpdu.get_lcid(), subpdu.get_sdu(), subpdu.get_sdu_length());
+        if (!con_res_rxed or (con_res_rxed and is_uecrid_successful)) {
+          if (subpdu.is_sdu()) {
+            rlc->write_pdu(subpdu.get_lcid(), subpdu.get_sdu(), subpdu.get_sdu_length());
+          }
         }
     }
   }

srsue/src/stack/mac_nr/dl_harq_nr.cc

@@ -235,7 +235,10 @@ void dl_harq_entity_nr::dl_harq_process_nr::tb_decoded(const mac_nr_grant_dl_t&
         logger.debug("Delivering PDU=%d bytes to Dissassemble and Demux unit (Temporal C-RNTI) not implemented",
                      grant.tbs);
         harq_entity->demux_unit->push_pdu_temp_crnti(std::move(result.payload), grant.tti);
-        result.ack = harq_entity->mac->received_contention_id(harq_entity->demux_unit->get_received_crueid());
+        result.ack = harq_entity->demux_unit->get_uecrid_successful();
+        if (not result.ack) {
+          reset();
+        }
       } else {
         logger.debug("Delivering PDU=%d bytes to Dissassemble and Demux unit", grant.tbs);
         harq_entity->demux_unit->push_pdu(std::move(result.payload), grant.tti);

srsue/src/stack/mac_nr/mac_nr.cc

@@ -65,7 +65,7 @@ int mac_nr::init(const mac_nr_args_t&  args_,
     return SRSRAN_ERROR;
   }
 
-  if (demux.init(rlc, phy) != SRSRAN_SUCCESS) {
+  if (demux.init(rlc, phy, this) != SRSRAN_SUCCESS) {
     logger.error("Couldn't initialize demux unit.");
     return SRSRAN_ERROR;
   }
@@ -349,11 +349,6 @@ void mac_nr::tb_decoded(const uint32_t cc_idx, const mac_nr_grant_dl_t& grant, t
 
     dl_harq.at(cc_idx)->tb_decoded(grant, std::move(result));
   }
-
-  // If proc ra is in contention resolution (RA connection request procedure)
-  if (proc_ra.is_contention_resolution() && grant.rnti == rntis.get_temp_rnti()) {
-    proc_ra.received_contention_resolution(contention_res_successful);
-  }
 }
 
 void mac_nr::new_grant_ul(const uint32_t cc_idx, const mac_nr_grant_ul_t& grant, tb_action_ul_t* action)
@@ -566,6 +561,7 @@ void mac_nr::process_pdus()
 bool mac_nr::received_contention_id(uint64_t rx_contention_id)
 {
   contention_res_successful = rntis.get_contention_id() == rx_contention_id;
+  proc_ra.received_contention_resolution(contention_res_successful);
   return contention_res_successful;
 }
 

srsue/src/stack/mac_nr/proc_ra_nr.cc

@@ -122,7 +122,7 @@ bool proc_ra_nr::has_rar_rnti()
 void proc_ra_nr::received_contention_resolution(bool is_successful)
 {
   std::lock_guard<std::mutex> lock(mutex);
-  ra_contention_resolution(is_successful);
+  ra_contention_resolution(is_successful, false);
 }
 
 void proc_ra_nr::timer_expired(uint32_t timer_id)
@@ -196,8 +196,6 @@ void proc_ra_nr::ra_response_reception(const mac_interface_phy_nr::tb_action_dl_
     return;
   }
 
-  // Stop rar timer
-  rar_timeout_timer.stop();
   if (tb.ack && tb.payload != nullptr) {
     srsran::mac_rar_pdu_nr pdu;
     if (!pdu.unpack(tb.payload->msg, tb.payload->N_bytes)) {
@@ -211,6 +209,9 @@ void proc_ra_nr::ra_response_reception(const mac_interface_phy_nr::tb_action_dl_
 
     for (auto& subpdu : pdu.get_subpdus()) {
       if (subpdu.has_rapid() && subpdu.get_rapid() == preamble_index) {
+        // Stop rar timer
+        rar_timeout_timer.stop();
+
         logger.debug("PROC RA NR: Setting UL grant and prepare Msg3");
         mac.set_temp_crnti(subpdu.get_temp_crnti());
 
@@ -231,18 +232,20 @@ void proc_ra_nr::ra_response_reception(const mac_interface_phy_nr::tb_action_dl_
         } else {
           preamble_backoff = 0;
         }
+
+        contention_resolution_timer.set(rach_cfg.ra_ContentionResolutionTimer,
+                                        [this](uint32_t tid) { timer_expired(tid); });
+        contention_resolution_timer.run();
+        logger.debug("Waiting for Contention Resolution");
+        state = WAITING_FOR_CONTENTION_RESOLUTION;
       }
     }
   }
-  contention_resolution_timer.set(rach_cfg.ra_ContentionResolutionTimer, [this](uint32_t tid) { timer_expired(tid); });
-  contention_resolution_timer.run();
-  logger.debug("Waiting for Contention Resolution");
-  state = WAITING_FOR_CONTENTION_RESOLUTION;
 }
 
 // TS 38.321 Section 5.1.5 2 ways to resolve contention resolution
 // if the C-RNTI MAC CE was included in Msg3: (only this one is implemented)
-void proc_ra_nr::ra_contention_resolution(bool received_con_res_matches_ue_id)
+void proc_ra_nr::ra_contention_resolution(bool is_successful, bool is_ul_grant)
 {
   if (state != WAITING_FOR_CONTENTION_RESOLUTION) {
     logger.warning(
@@ -251,15 +254,20 @@ void proc_ra_nr::ra_contention_resolution(bool received_con_res_matches_ue_id)
         srsran::enum_to_text(state_str_nr, (uint32_t)ra_state_t::MAX_RA_STATES, WAITING_FOR_CONTENTION_RESOLUTION));
     return;
   }
-  if (started_by == initiators_t::RRC || started_by == initiators_t::MAC || received_con_res_matches_ue_id) {
-    if (received_con_res_matches_ue_id) {
-      logger.info("Received CONRES ID matches transmitted UE ID");
+  if (started_by == initiators_t::RRC || started_by == initiators_t::MAC || is_successful) {
+    if (is_successful) {
+      if (is_ul_grant) {
+        logger.info("PDCCH to C-RNTI received with a new UL grant of transmission");
+      } else {
+        logger.info("Received CONRES ID matches transmitted UE ID");
+      }
+      contention_resolution_timer.stop();
+      state = WAITING_FOR_COMPLETION;
+      ra_completion();
     } else {
-      logger.info("PDCCH to C-RNTI received with a new UL grant of transmission");
+      logger.info("Received CONRES ID DOES NOT match transmitted UE ID");
+      mac.set_temp_crnti(SRSRAN_INVALID_RNTI);
     }
-    contention_resolution_timer.stop();
-    state = WAITING_FOR_COMPLETION;
-    ra_completion();
   } else {
     logger.error("Not started by the correct initiator MAC or RRC");
   }
@@ -375,7 +383,7 @@ void proc_ra_nr::handle_rar_pdu(mac_interface_phy_nr::tb_action_dl_result_t& res
 // Called from PHY thread, defer actions therefore.
 void proc_ra_nr::pdcch_to_crnti()
 {
-  task_queue.push([this]() { ra_contention_resolution(false); });
+  task_queue.push([this]() { ra_contention_resolution(true, true); });
 }
 
 bool proc_ra_nr::is_contention_resolution()