ue,mac_nr: add basic SR procedure

the current implementation support only one SR config
and doesn't support the prohibit timer

lib/include/srsran/interfaces/mac_interface_types.h

@@ -136,6 +136,20 @@ struct rach_nr_cfg_t {
   }
 };
 
+// 38.321 Section 5.4.4 (only one config supported right now)
+struct sr_cfg_item_nr_t {
+  uint8_t sched_request_id;
+  uint8_t prohibit_timer;
+  uint8_t trans_max;
+};
+
+#define SRSRAN_MAX_MAX_NR_OF_SR_CFG_PER_CELL_GROUP (8)
+struct sr_cfg_nr_t {
+  bool enabled;
+  uint8_t          num_items;
+  sr_cfg_item_nr_t item[SRSRAN_MAX_MAX_NR_OF_SR_CFG_PER_CELL_GROUP];
+};
+
 struct mac_cfg_t {
   // Default constructor with default values as in 36.331 9.2.2
   mac_cfg_t() { set_defaults(); }

lib/include/srsran/interfaces/ue_nr_interfaces.h

@@ -98,10 +98,11 @@ public:
 class mac_interface_rrc_nr
 {
 public:
-  virtual void setup_lcid(const srsran::logical_channel_config_t& config) = 0;
+  // Config calls that return SRSRAN_SUCCESS or SRSRAN_ERROR
-  virtual void set_config(const srsran::bsr_cfg_t& bsr_cfg)               = 0;
+  virtual void    setup_lcid(const srsran::logical_channel_config_t& config) = 0;
-  virtual void set_config(const srsran::sr_cfg_t& sr_cfg)                 = 0;
+  virtual void    set_config(const srsran::bsr_cfg_t& bsr_cfg)               = 0;
-  virtual void set_config(const srsran::rach_nr_cfg_t& rach_cfg)          = 0;
+  virtual int32_t set_config(const srsran::sr_cfg_nr_t& sr_cfg)              = 0;
+  virtual void    set_config(const srsran::rach_nr_cfg_t& rach_cfg)          = 0;
 
   // RRC triggers MAC ra procedure
   virtual void start_ra_procedure() = 0;

srsue/hdr/stack/mac_nr/mac_nr.h

@@ -15,6 +15,7 @@
 
 #include "mac_nr_interfaces.h"
 #include "proc_ra_nr.h"
+#include "proc_sr_nr.h"
 #include "srsran/common/block_queue.h"
 #include "srsran/common/mac_pcap.h"
 #include "srsran/interfaces/mac_interface_types.h"
@@ -66,13 +67,13 @@ public:
   void get_metrics(mac_metrics_t* metrics);
 
   /// Interface for RRC (RRC -> MAC)
-  void setup_lcid(const srsran::logical_channel_config_t& config);
+  void    setup_lcid(const srsran::logical_channel_config_t& config);
-  void set_config(const srsran::bsr_cfg_t& bsr_cfg);
+  void    set_config(const srsran::bsr_cfg_t& bsr_cfg);
-  void set_config(const srsran::sr_cfg_t& sr_cfg);
+  int32_t set_config(const srsran::sr_cfg_nr_t& sr_cfg);
-  void set_config(const srsran::rach_nr_cfg_t& rach_cfg);
+  void    set_config(const srsran::rach_nr_cfg_t& rach_cfg);
-  void set_contention_id(const uint64_t ue_identity);
+  void    set_contention_id(const uint64_t ue_identity);
-  bool set_crnti(const uint16_t crnti);
+  bool    set_crnti(const uint16_t crnti);
-  void start_ra_procedure();
+  void    start_ra_procedure();
 
   /// procedure ra nr interface
   uint64_t get_contention_id();
@@ -144,6 +145,7 @@ private:
 
   // MAC Uplink-related procedures
   proc_ra_nr proc_ra;
+  proc_sr_nr proc_sr;
   mux_nr     mux;
 };
 

srsue/hdr/stack/mac_nr/proc_ra_nr.h

@@ -47,6 +47,7 @@ public:
   void pdcch_to_crnti();
 
   void start_by_rrc();
+  void start_by_mac();
   void reset();
 
 private:

srsue/hdr/stack/mac_nr/proc_sr_nr.h

@@ -0,0 +1,57 @@
+/**
+ *
+ * \section COPYRIGHT
+ *
+ * Copyright 2013-2021 Software Radio Systems Limited
+ *
+ * By using this file, you agree to the terms and conditions set
+ * forth in the LICENSE file which can be found at the top level of
+ * the distribution.
+ *
+ */
+
+#ifndef SRSUE_PROC_SR_NR_H
+#define SRSUE_PROC_SR_NR_H
+
+#include "srsran/interfaces/ue_mac_interfaces.h"
+#include "srsran/srslog/srslog.h"
+#include <stdint.h>
+
+/// Scheduling Request procedure as defined in 5.4.4 of 38.321
+/// Note: currently only a single SR config for all logical channels is supported
+
+namespace srsue {
+
+class proc_ra_nr;
+class phy_interface_mac_nr;
+class rrc_interface_mac;
+
+class proc_sr_nr
+{
+public:
+  explicit proc_sr_nr(srslog::basic_logger& logger);
+  int32_t init(proc_ra_nr* ra_, phy_interface_mac_nr* phy_, rrc_interface_mac* rrc_);
+  void    step(uint32_t tti);
+  int32_t set_config(const srsran::sr_cfg_nr_t& cfg);
+  void    reset();
+  void    start();
+
+private:
+  bool need_tx(uint32_t tti);
+
+  int  sr_counter    = 0;
+  bool is_pending_sr = 0;
+
+  srsran::sr_cfg_nr_t cfg = {};
+
+  proc_ra_nr*           ra  = nullptr;
+  rrc_interface_mac*    rrc = nullptr;
+  phy_interface_mac_nr* phy = nullptr;
+  srslog::basic_logger& logger;
+
+  bool initiated = false;
+};
+
+} // namespace srsue
+
+#endif // SRSUE_PROC_SR_H

srsue/src/stack/mac_nr/CMakeLists.txt

@@ -6,6 +6,6 @@
 # the distribution.
 #
 
-set(SOURCES mac_nr.cc proc_ra_nr.cc mux_nr.cc)
+set(SOURCES mac_nr.cc proc_ra_nr.cc proc_sr_nr.cc mux_nr.cc)
 add_library(srsue_mac_nr STATIC ${SOURCES})
 target_link_libraries(srsue_mac_nr srsran_mac)

srsue/src/stack/mac_nr/mac_nr.cc

@@ -17,9 +17,13 @@
 namespace srsue {
 
 mac_nr::mac_nr(srsran::ext_task_sched_handle task_sched_) :
-  task_sched(task_sched_), logger(srslog::fetch_basic_logger("MAC")), proc_ra(logger), mux(logger), pcap(nullptr)
+  task_sched(task_sched_),
-{
+  logger(srslog::fetch_basic_logger("MAC")),
-}
+  proc_ra(logger),
+  proc_sr(logger),
+  mux(logger),
+  pcap(nullptr)
+{}
 
 mac_nr::~mac_nr()
 {
@@ -307,10 +311,9 @@ void mac_nr::set_config(const srsran::bsr_cfg_t& bsr_cfg)
   logger.warning("Not handling BSR config yet");
 }
 
-void mac_nr::set_config(const srsran::sr_cfg_t& sr_cfg)
+int32_t mac_nr::set_config(const srsran::sr_cfg_nr_t& sr_cfg)
 {
-  logger.info("Scheduling Request Config DSR tansmax %d", sr_cfg.dsr_transmax);
+  return proc_sr.set_config(sr_cfg);
-  logger.warning("Not Scheduling Request Config yet");
 }
 
 void mac_nr::set_config(const srsran::rach_nr_cfg_t& rach_cfg)

srsue/src/stack/mac_nr/proc_ra_nr.cc

@@ -74,6 +74,18 @@ void proc_ra_nr::start_by_rrc()
   ra_procedure_initialization();
 }
 
+void proc_ra_nr::start_by_mac()
+{
+  if (state != IDLE || configured == false) {
+    logger.warning("Trying to start PRACH by MAC order in invalid state (%s)",
+                   srsran::enum_to_text(state_str_nr, (uint32_t)ra_state_t::MAX_RA_STATES, state));
+    return;
+  }
+  started_by = initiators_t::MAC;
+  logger.info("Starting PRACH by MAC order");
+  ra_procedure_initialization();
+}
+
 bool proc_ra_nr::is_rar_opportunity(uint32_t tti)
 {
   // TODO replace second "&&"" by rar_timeout_timer.running if timer thread safe and delayed starting (tti+3)

srsue/src/stack/mac_nr/proc_sr_nr.cc

@@ -0,0 +1,125 @@
+/**
+ *
+ * \section COPYRIGHT
+ *
+ * Copyright 2013-2021 Software Radio Systems Limited
+ *
+ * By using this file, you agree to the terms and conditions set
+ * forth in the LICENSE file which can be found at the top level of
+ * the distribution.
+ *
+ */
+
+#include "srsue/hdr/stack/mac_nr/proc_sr_nr.h"
+#include "srsran/common/standard_streams.h"
+#include "srsran/interfaces/ue_phy_interfaces.h"
+#include "srsran/interfaces/ue_rrc_interfaces.h"
+#include "srsue/hdr/stack/mac_nr/proc_ra_nr.h"
+
+namespace srsue {
+
+proc_sr_nr::proc_sr_nr(srslog::basic_logger& logger) : logger(logger) {}
+
+int32_t proc_sr_nr::init(proc_ra_nr* ra_, phy_interface_mac_nr* phy_, rrc_interface_mac* rrc_)
+{
+  rrc        = rrc_;
+  ra         = ra_;
+  phy        = phy_;
+  initiated  = true;
+  sr_counter = 0;
+  return SRSRAN_SUCCESS;
+}
+
+void proc_sr_nr::reset()
+{
+  is_pending_sr = false;
+}
+
+bool proc_sr_nr::need_tx(uint32_t tti)
+{
+  int last_tx_tti = 0; // FIXME: phy->sr_last_tx_tti();
+  logger.debug("SR:    need_tx(): last_tx_tti=%d, tti=%d", last_tx_tti, tti);
+  if (last_tx_tti >= 0) {
+    // TODO: implement prohibit timer
+    if (TTI_SUB(last_tx_tti, tti) >= 8) {
+      return true;
+    }
+  }
+  return false;
+}
+
+int32_t proc_sr_nr::set_config(const srsran::sr_cfg_nr_t& cfg_)
+{
+  // disable by default
+  cfg.enabled = false;
+
+  if (cfg_.num_items != 1) {
+    logger.error("Only one SR config supported. Disabling SR.");
+    return SRSRAN_ERROR;
+  }
+
+  if (cfg_.enabled && cfg_.item[0].trans_max == 0) {
+    logger.error("Zero is an invalid value for sr-TransMax (n4, n8, n16, n32, n64 are supported). Disabling SR.");
+    return SRSRAN_ERROR;
+  }
+
+  if (cfg_.enabled && cfg_.item[0].prohibit_timer > 0) {
+    logger.error("sr-ProhibitTimer isn't supported. Disabling SR.");
+    return SRSRAN_ERROR;
+  }
+
+  if (cfg_.enabled) {
+    logger.info("SR:    Set sr-TransMax=%d", cfg_.item[0].trans_max);
+  }
+
+  // store config
+  cfg = cfg_;
+
+  return SRSRAN_SUCCESS;
+}
+
+void proc_sr_nr::step(uint32_t tti)
+{
+  if (initiated) {
+    if (is_pending_sr) {
+      if (cfg.enabled) {
+        if (sr_counter < cfg.item[0].trans_max) {
+          if (sr_counter == 0 || need_tx(tti)) {
+            sr_counter++;
+            logger.info("SR:    Signalling PHY sr_counter=%d", sr_counter);
+            phy->sr_send(0); // @xavierarteaga what is the ID you expect here?
+          }
+        } else {
+          if (need_tx(tti)) {
+            logger.info("SR:    Releasing PUCCH/SRS resources, sr_counter=%d, sr-TransMax=%d",
+                        sr_counter,
+                        cfg.item[0].trans_max);
+            srsran::console("Scheduling request failed: releasing RRC connection...\n");
+            rrc->release_pucch_srs();
+            // TODO:
+            // - clear any configured downlink assignments and uplink grants;
+            // - clear any PUSCH resources for semi-persistent CSI reporting;
+            ra->start_by_mac();
+            reset();
+          }
+        }
+      } else {
+        logger.info("SR:    PUCCH not configured. Starting RA procedure");
+        ra->start_by_mac();
+        reset();
+      }
+    }
+  }
+}
+
+void proc_sr_nr::start()
+{
+  if (initiated) {
+    if (!is_pending_sr) {
+      sr_counter    = 0;
+      is_pending_sr = true;
+    }
+  }
+}
+
+} // namespace srsue

srsue/src/stack/rrc/rrc_nr.cc

@@ -527,14 +527,24 @@ bool rrc_nr::apply_rlc_add_mod(const rlc_bearer_cfg_s& rlc_bearer_cfg)
 bool rrc_nr::apply_mac_cell_group(const mac_cell_group_cfg_s& mac_cell_group_cfg)
 {
   if (mac_cell_group_cfg.sched_request_cfg_present) {
-    sr_cfg_t sr_cfg;
     if (mac_cell_group_cfg.sched_request_cfg.sched_request_to_add_mod_list_present) {
-      if (mac_cell_group_cfg.sched_request_cfg.sched_request_to_add_mod_list.size() > 1) {
+      if (mac_cell_group_cfg.sched_request_cfg.sched_request_to_add_mod_list.size() == 1) {
+        const sched_request_to_add_mod_s& asn1_cfg =
+            mac_cell_group_cfg.sched_request_cfg.sched_request_to_add_mod_list[0];
+        sr_cfg_nr_t sr_cfg              = {};
+        sr_cfg.num_items                = 1;
+        sr_cfg.item[0].sched_request_id = asn1_cfg.sched_request_id;
+        sr_cfg.item[0].trans_max        = asn1_cfg.sr_trans_max.to_number();
+        if (asn1_cfg.sr_prohibit_timer_present) {
+          sr_cfg.item[0].prohibit_timer = asn1_cfg.sr_trans_max;
+        }
+        if (mac->set_config(sr_cfg) != SRSRAN_SUCCESS) {
+          logger.error("Couldn't configure SR procedure.");
+          return false;
+        }
+      } else {
         logger.warning("Only handling 1 scheduling request index to add");
         return false;
-      } else {
-        sr_cfg.dsr_transmax = mac_cell_group_cfg.sched_request_cfg.sched_request_to_add_mod_list[1].sr_trans_max;
-        mac->set_config(sr_cfg);
       }
     }