ue,sa: add minimal cell selection and setup request procedure

skeleton based on EUTRA procedures

srsue/hdr/stack/rrc_nr/rrc_nr.h

@@ -132,7 +132,9 @@ public:
 
 private:
   // senders
+  void send_setup_request(srsran::nr_establishment_cause_t cause);
   void send_ul_info_transfer(srsran::unique_byte_buffer_t nas_msg);
+  void send_ul_ccch_msg(const asn1::rrc_nr::ul_ccch_msg_s& msg);
 
   srsran::task_sched_handle task_sched;
   struct cmd_msg_t {
@@ -159,6 +161,10 @@ private:
 
   meas_cell_list<meas_cell_nr> meas_cells;
 
+  // PLMN
+  bool                         plmn_is_selected = false;
+  srsran::unique_byte_buffer_t dedicated_info_nas;
+
   const uint32_t                      sim_measurement_timer_duration_ms = 250;
   uint32_t                            sim_measurement_carrier_freq_r15;
   srsran::timer_handler::unique_timer sim_measurement_timer;
@@ -173,7 +179,7 @@ private:
   const static char* rrc_nr_state_text[RRC_NR_STATE_N_ITEMS];
   rrc_nr_state_t     state = RRC_NR_STATE_IDLE;
 
-  // Stores the state of the PHy configuration setting
+  // Stores the state of the PHY configuration setting
   enum {
     PHY_CFG_STATE_NONE = 0,
     PHY_CFG_STATE_APPLY_SP_CELL,
@@ -219,9 +225,14 @@ private:
   typedef enum { mcg_srb1, en_dc_srb3, nr } reconf_initiator_t;
 
   // RRC procedures
+  enum class cell_search_result_t { changed_cell, same_cell, no_cell };
+  class cell_selection_proc;
   class connection_reconf_no_ho_proc;
+  class setup_request_proc;
 
-  srsran::proc_t<connection_reconf_no_ho_proc> conn_recfg_proc;
+  srsran::proc_t<cell_selection_proc, cell_search_result_t> cell_selector;
+  srsran::proc_t<connection_reconf_no_ho_proc>              conn_recfg_proc;
+  srsran::proc_t<setup_request_proc>                        setup_req_proc;
 
   srsran::proc_manager_list_t callback_list;
 };

srsue/hdr/stack/rrc_nr/rrc_nr_procedures.h

@@ -22,10 +22,65 @@ namespace srsue {
  *         Procedures
  *******************************/
 
+class rrc_nr::cell_selection_proc
+{
+public:
+  using cell_selection_complete_ev = srsran::proc_result_t<cell_search_result_t>;
+
+  explicit cell_selection_proc(rrc_nr& parent_);
+  srsran::proc_outcome_t init();
+  srsran::proc_outcome_t step();
+  cell_search_result_t   get_result() const { return cell_search_ret; }
+  static const char*     name() { return "Cell Selection"; }
+  srsran::proc_outcome_t react(const bool& event);
+  void                   then(const srsran::proc_result_t<cell_search_result_t>& proc_result) const;
+
+private:
+  bool                   is_serv_cell_suitable() const;
+  srsran::proc_outcome_t set_proc_complete();
+
+  // consts
+  rrc_nr&                       rrc_handle;
+  meas_cell_list<meas_cell_nr>& meas_cells;
+
+  // state variables
+  enum class search_state_t { cell_selection, serv_cell_camp, cell_config, cell_search };
+  cell_search_result_t                                            cell_search_ret;
+  search_state_t                                                  state;
+  srsran::proc_future_t<rrc_interface_phy_lte::cell_search_ret_t> cell_search_fut;
+  srsran::proc_future_t<void>                                     serv_cell_cfg_fut;
+  phy_cell_t                                                      init_serv_cell;
+};
+
+class rrc_nr::setup_request_proc
+{
+public:
+  explicit setup_request_proc(rrc_nr& parent_);
+  srsran::proc_outcome_t init(srsran::nr_establishment_cause_t cause_,
+                              srsran::unique_byte_buffer_t     dedicated_info_nas_);
+  srsran::proc_outcome_t step();
+  void                   then(const srsran::proc_state_t& result);
+  srsran::proc_outcome_t react(const cell_selection_proc::cell_selection_complete_ev& e);
+  static const char*     name() { return "Setup Request"; }
+
+private:
+  // const
+  rrc_nr&               rrc_handle;
+  srslog::basic_logger& logger;
+  // args
+  srsran::nr_establishment_cause_t cause;
+  srsran::unique_byte_buffer_t     dedicated_info_nas;
+
+  // state variables
+  enum class state_t { cell_selection, config_serving_cell, wait_t300 } state;
+  cell_search_result_t        cell_search_ret;
+  srsran::proc_future_t<void> serv_cfg_fut;
+};
+
 class rrc_nr::connection_reconf_no_ho_proc
 {
 public:
-  explicit connection_reconf_no_ho_proc(rrc_nr* parent_);
+  explicit connection_reconf_no_ho_proc(rrc_nr& parent_);
   srsran::proc_outcome_t init(const reconf_initiator_t  initiator_,
                               const bool                endc_release_and_add_r15,
                               const bool                nr_secondary_cell_group_cfg_r15_present,
@@ -41,7 +96,7 @@ public:
 
 private:
   // const
-  rrc_nr*                        rrc_ptr = nullptr;
+  rrc_nr&                        rrc_handle;
   reconf_initiator_t             initiator;
   asn1::rrc_nr::rrc_recfg_s      rrc_recfg;
   asn1::rrc_nr::cell_group_cfg_s cell_group_cfg;

srsue/src/stack/rrc_nr/rrc_nr.cc

@@ -27,7 +27,12 @@ namespace srsue {
 const char* rrc_nr::rrc_nr_state_text[] = {"IDLE", "CONNECTED", "CONNECTED-INACTIVE"};
 
 rrc_nr::rrc_nr(srsran::task_sched_handle task_sched_) :
-  logger(srslog::fetch_basic_logger("RRC-NR")), task_sched(task_sched_), conn_recfg_proc(this), meas_cells(task_sched_)
+  logger(srslog::fetch_basic_logger("RRC-NR")),
+  task_sched(task_sched_),
+  conn_recfg_proc(*this),
+  setup_req_proc(*this),
+  cell_selector(*this),
+  meas_cells(task_sched_)
 {}
 
 rrc_nr::~rrc_nr() = default;
@@ -53,6 +58,8 @@ int rrc_nr::init(phy_interface_rrc_nr*       phy_,
   stack     = stack_;
   args      = args_;
 
+  plmn_is_selected = true; // short-cut SA test
+
   running               = true;
   sim_measurement_timer = task_sched.get_unique_timer();
   return SRSRAN_SUCCESS;
@@ -221,8 +228,13 @@ bool rrc_nr::is_connected()
   return false;
 }
 
-int rrc_nr::connection_request(srsran::nr_establishment_cause_t cause, srsran::unique_byte_buffer_t sdu)
+int rrc_nr::connection_request(srsran::nr_establishment_cause_t cause, srsran::unique_byte_buffer_t dedicated_info_nas_)
 {
+  if (not setup_req_proc.launch(cause, std::move(dedicated_info_nas_))) {
+    logger.error("Failed to initiate setup request procedure");
+    return SRSRAN_ERROR;
+  }
+  callback_list.add_proc(setup_req_proc);
   return SRSRAN_SUCCESS;
 }
 
@@ -242,6 +254,58 @@ void rrc_nr::send_ul_info_transfer(unique_byte_buffer_t nas_msg)
   logger.warning("%s not implemented yet.", __FUNCTION__);
 }
 
+void rrc_nr::send_setup_request(srsran::nr_establishment_cause_t cause)
+{
+  logger.debug("Preparing RRC Setup Request");
+
+  // Prepare SetupRequest packet
+  ul_ccch_msg_s            ul_ccch_msg;
+  rrc_setup_request_ies_s* rrc_setup_req = &ul_ccch_msg.msg.set_c1().set_rrc_setup_request().rrc_setup_request;
+
+  // TODO: implement ng_minus5_g_s_tmsi_part1
+  rrc_setup_req->ue_id.set_random_value();
+  // TODO use proper RNG
+  uint64_t random_id = 0;
+  for (uint i = 0; i < 5; i++) { // fill random ID bytewise, 40 bits = 5 bytes
+    random_id |= ((uint64_t)rand() & 0xFF) << i * 8;
+  }
+  rrc_setup_req->ue_id.random_value().from_number(random_id);
+  rrc_setup_req->establishment_cause = (establishment_cause_opts::options)cause;
+
+  send_ul_ccch_msg(ul_ccch_msg);
+}
+
+void rrc_nr::send_ul_ccch_msg(const asn1::rrc_nr::ul_ccch_msg_s& msg)
+{
+  unique_byte_buffer_t pdu = srsran::make_byte_buffer();
+  if (pdu == nullptr) {
+    logger.error("Couldn't allocate PDU in %s().", __FUNCTION__);
+    return;
+  }
+
+  asn1::bit_ref bref(pdu->msg, pdu->get_tailroom());
+  msg.pack(bref);
+  bref.align_bytes_zero();
+  pdu->N_bytes = (uint32_t)bref.distance_bytes(pdu->msg);
+  pdu->set_timestamp();
+
+  // Set UE contention resolution ID in MAC
+  uint64_t uecri      = 0;
+  uint8_t* ue_cri_ptr = (uint8_t*)&uecri;
+  uint32_t nbytes     = 6;
+  for (uint32_t i = 0; i < nbytes; i++) {
+    ue_cri_ptr[nbytes - i - 1] = pdu->msg[i];
+  }
+
+  logger.debug("Setting UE contention resolution ID: %" PRIu64 "", uecri);
+  mac->set_contention_id(uecri);
+
+  uint32_t lcid = 0;
+  log_rrc_message(get_rb_name(lcid), Tx, pdu.get(), msg, msg.msg.c1().type().to_string());
+
+  rlc->write_sdu(lcid, std::move(pdu));
+}
+
 // EUTRA-RRC interface
 int rrc_nr::get_eutra_nr_capabilities(srsran::byte_buffer_t* eutra_nr_caps_pdu)
 {
@@ -1542,6 +1606,7 @@ bool rrc_nr::apply_radio_bearer_cfg(const radio_bearer_cfg_s& radio_bearer_cfg)
   }
   return true;
 }
+
 // RLC interface
 void rrc_nr::max_retx_attempted() {}
 void rrc_nr::protocol_failure() {}
@@ -1553,6 +1618,7 @@ void rrc_nr::ra_completed()
   phy->set_config(phy_cfg);
   phy_cfg_state = PHY_CFG_STATE_RA_COMPLETED;
 }
+
 void rrc_nr::ra_problem()
 {
   rrc_eutra->nr_scg_failure_information(scg_failure_cause_t::random_access_problem);

srsue/src/stack/rrc_nr/rrc_nr_procedures.cc

@@ -13,10 +13,10 @@
 #include "srsue/hdr/stack/rrc_nr/rrc_nr_procedures.h"
 #include "srsran/common/standard_streams.h"
 
-#define Error(fmt, ...) rrc_ptr->logger.error("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
+#define Error(fmt, ...) rrc_handle.logger.error("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
-#define Warning(fmt, ...) rrc_ptr->logger.warning("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
+#define Warning(fmt, ...) rrc_handle.logger.warning("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
-#define Info(fmt, ...) rrc_ptr->logger.info("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
+#define Info(fmt, ...) rrc_handle.logger.info("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
-#define Debug(fmt, ...) rrc_ptr->logger.debug("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
+#define Debug(fmt, ...) rrc_handle.logger.debug("Proc \"%s\" - " fmt, name(), ##__VA_ARGS__)
 
 using namespace asn1::rrc_nr;
 using namespace asn1;
@@ -24,7 +24,8 @@ using namespace srsran;
 
 namespace srsue {
 
-rrc_nr::connection_reconf_no_ho_proc::connection_reconf_no_ho_proc(rrc_nr* parent_) : rrc_ptr(parent_), initiator(nr) {}
+rrc_nr::connection_reconf_no_ho_proc::connection_reconf_no_ho_proc(rrc_nr& parent_) : rrc_handle(parent_), initiator(nr)
+{}
 
 proc_outcome_t rrc_nr::connection_reconf_no_ho_proc::init(const reconf_initiator_t initiator_,
                                                           const bool               endc_release_and_add_r15,
@@ -55,6 +56,7 @@ proc_outcome_t rrc_nr::connection_reconf_no_ho_proc::init(const reconf_initiator
     rrc_ptr->log_rrc_message(
         "RRC NR Reconfiguration", Rx, nr_secondary_cell_group_cfg_r15, rrc_recfg, "NR Secondary Cell Group Cfg R15");
 #endif
+
     if (rrc_recfg.crit_exts.type() != asn1::rrc_nr::rrc_recfg_s::crit_exts_c_::types::rrc_recfg) {
       Error("Reconfiguration does not contain Secondary Cell Group Config");
       return proc_outcome_t::error;
@@ -83,14 +85,14 @@ proc_outcome_t rrc_nr::connection_reconf_no_ho_proc::init(const reconf_initiator
 #endif
 
     Info("Applying Cell Group Cfg");
-    if (!rrc_ptr->apply_cell_group_cfg(cell_group_cfg)) {
+    if (!rrc_handle.apply_cell_group_cfg(cell_group_cfg)) {
       return proc_outcome_t::error;
     }
   }
 
   if (sk_counter_r15_present) {
     Info("Applying Cell Group Cfg");
-    if (!rrc_ptr->configure_sk_counter((uint16_t)sk_counter_r15)) {
+    if (!rrc_handle.configure_sk_counter((uint16_t)sk_counter_r15)) {
       return proc_outcome_t::error;
     }
   }
@@ -110,7 +112,7 @@ proc_outcome_t rrc_nr::connection_reconf_no_ho_proc::init(const reconf_initiator
 #endif
 
     Info("Applying Radio Bearer Cfg");
-    if (!rrc_ptr->apply_radio_bearer_cfg(radio_bearer_cfg)) {
+    if (!rrc_handle.apply_radio_bearer_cfg(radio_bearer_cfg)) {
       return proc_outcome_t::error;
     }
   }
@@ -140,12 +142,12 @@ void rrc_nr::connection_reconf_no_ho_proc::then(const srsran::proc_state_t& resu
   if (result.is_success()) {
     Info("Finished %s successfully", name());
     srsran::console("RRC NR reconfiguration successful.\n");
-    rrc_ptr->rrc_eutra->nr_rrc_con_reconfig_complete(true);
+    rrc_handle.rrc_eutra->nr_rrc_con_reconfig_complete(true);
   } else {
     // 5.3.5.8.2 Inability to comply with RRCReconfiguration
     switch (initiator) {
       case reconf_initiator_t::mcg_srb1:
-        rrc_ptr->rrc_eutra->nr_notify_reconfiguration_failure();
+        rrc_handle.rrc_eutra->nr_notify_reconfiguration_failure();
         break;
       default:
         Warning("Reconfiguration failure not implemented for initiator %d", initiator);
@@ -157,4 +159,196 @@ void rrc_nr::connection_reconf_no_ho_proc::then(const srsran::proc_state_t& resu
   return;
 }
 
+/**************************************
+ *     RRC Setup Request Procedure
+ *************************************/
+
+rrc_nr::setup_request_proc::setup_request_proc(rrc_nr& parent_) :
+  rrc_handle(parent_), logger(srslog::fetch_basic_logger("RRC"))
+{}
+
+proc_outcome_t rrc_nr::setup_request_proc::init(srsran::nr_establishment_cause_t cause_,
+                                                srsran::unique_byte_buffer_t     dedicated_info_nas_)
+{
+  cause              = cause_;
+  dedicated_info_nas = std::move(dedicated_info_nas_);
+
+  if (!rrc_handle.plmn_is_selected) {
+    Error("Trying to connect but PLMN not selected.");
+    return proc_outcome_t::error;
+  }
+
+  if (rrc_handle.state != RRC_NR_STATE_IDLE) {
+    logger.warning("Requested RRC connection establishment while not in IDLE");
+    return proc_outcome_t::error;
+  }
+
+  // TODO: add T302 handling
+
+  Info("Initiation of Connection establishment procedure");
+
+  cell_search_ret = cell_search_result_t::no_cell;
+
+  state = state_t::cell_selection;
+  if (rrc_handle.cell_selector.is_idle()) {
+    // No one is running cell selection
+    if (not rrc_handle.cell_selector.launch()) {
+      Error("Failed to initiate cell selection procedure...");
+      return proc_outcome_t::error;
+    }
+    rrc_handle.callback_list.add_proc(rrc_handle.cell_selector);
+  } else {
+    Info("Cell selection proc already on-going. Wait for its result");
+  }
+  return proc_outcome_t::yield;
+}
+
+proc_outcome_t rrc_nr::setup_request_proc::step()
+{
+  if (state == state_t::cell_selection) {
+    // NOTE: cell selection will signal back with an event trigger
+    return proc_outcome_t::yield;
+  }
+
+  if (state == state_t::config_serving_cell) {
+    // TODO: start serving cell config and start T300
+
+    // Send setup request message to lower layers
+    rrc_handle.send_setup_request(cause);
+
+    Info("Waiting for RRCSetup/Reject or expiry");
+    state = state_t::wait_t300;
+    return step();
+
+  } else if (state == state_t::wait_t300) {
+    // TODO: add T300 waiting
+  }
+
+  return proc_outcome_t::error;
+}
+
+void rrc_nr::setup_request_proc::then(const srsran::proc_state_t& result)
+{
+  if (result.is_error()) {
+    logger.warning("Could not establish connection. Deallocating dedicatedInfoNAS PDU");
+    dedicated_info_nas.reset();
+    rrc_handle.dedicated_info_nas.reset();
+  } else {
+    Info("Finished connection request procedure successfully.");
+  }
+  // TODO: signal back to NAS
+  // rrc_handle.nas->connection_request_completed(result.is_success());
+}
+
+srsran::proc_outcome_t rrc_nr::setup_request_proc::react(const cell_selection_proc::cell_selection_complete_ev& e)
+{
+  if (state != state_t::cell_selection) {
+    // ignore if we are not expecting an cell selection result
+    return proc_outcome_t::yield;
+  }
+  if (e.is_error()) {
+    return proc_outcome_t::error;
+  }
+  cell_search_ret = *e.value();
+  // .. and SI acquisition
+  // TODO @ismagom use appropiate PHY interface
+  if (true /*rrc_handle.phy->cell_is_camping()*/) {
+    // TODO: Set default configurations
+    // rrc_handle.set_phy_default();
+    // rrc_handle.set_mac_default();
+
+    // CCCH configuration applied already at start
+    // timeAlignmentCommon applied in configure_serving_cell
+
+    Info("Configuring serving cell...");
+    state = state_t::config_serving_cell;
+
+    // Skip SI acquisition
+    return step();
+  } else {
+    switch (cell_search_ret) {
+      case cell_search_result_t::same_cell:
+        logger.warning("Did not reselect cell but serving cell is out-of-sync.");
+        break;
+      case cell_search_result_t::changed_cell:
+        logger.warning("Selected a new cell but could not camp on. Setting out-of-sync.");
+        break;
+      default:
+        logger.warning("Could not find any suitable cell to connect");
+    }
+    return proc_outcome_t::error;
+  }
+}
+
+/**************************************
+ *       Basic Cell Selection Procedure
+ *************************************/
+
+rrc_nr::cell_selection_proc::cell_selection_proc(rrc_nr& parent_) :
+  rrc_handle(parent_), meas_cells(rrc_handle.meas_cells)
+{}
+
+/// Verifies if serving cell passes selection criteria, UE is camping, and required SIBs were obtained
+bool rrc_nr::cell_selection_proc::is_serv_cell_suitable() const
+{
+  // TODO: add selection criteria
+  return true;
+}
+
+/// Called on procedure exit to set result
+proc_outcome_t rrc_nr::cell_selection_proc::set_proc_complete()
+{
+  if (is_serv_cell_suitable()) {
+    cell_search_ret = is_same_cell(init_serv_cell, meas_cells.serving_cell()) ? cell_search_result_t::same_cell
+                                                                              : cell_search_result_t::changed_cell;
+    return proc_outcome_t::success;
+  }
+  cell_search_ret = cell_search_result_t::no_cell;
+  return proc_outcome_t::error;
+}
+
+proc_outcome_t rrc_nr::cell_selection_proc::init()
+{
+  init_serv_cell = meas_cells.serving_cell().phy_cell;
+
+  // Skip cell selection if serving cell is suitable and there are no stronger neighbours in same earfcn
+  if (is_serv_cell_suitable()) {
+    Debug("Skipping cell selection procedure as there are no stronger neighbours in same EARFCN.");
+    return set_proc_complete();
+  }
+
+  // TODO: add full cell selection
+  return set_proc_complete();
+}
+
+proc_outcome_t rrc_nr::cell_selection_proc::step()
+{
+  switch (state) {
+    case search_state_t::cell_selection:
+      // this state waits for phy event
+      return proc_outcome_t::yield;
+    case search_state_t::serv_cell_camp:
+      // this state waits for phy event
+      return proc_outcome_t::yield;
+    case search_state_t::cell_config:
+      // return step_cell_config();
+      return proc_outcome_t::yield;
+    case search_state_t::cell_search:
+      // return step_cell_search();
+      return proc_outcome_t::yield;
+  }
+  return proc_outcome_t::error;
+}
+
+void rrc_nr::cell_selection_proc::then(const srsran::proc_result_t<cell_search_result_t>& proc_result) const
+{
+  Info("Completed with %s.", proc_result.is_success() ? "success" : "failure");
+  // Inform Connection Request Procedure
+  rrc_handle.task_sched.defer_task([this, proc_result]() {
+    if (rrc_handle.setup_req_proc.is_busy()) {
+      rrc_handle.setup_req_proc.trigger(proc_result);
+    }
+  });
+}
+
 } // namespace srsue