ue,rrc,prach: receive nof_preambles, use random preamble and ue identity

lib/include/srsran/interfaces/mac_interface_types.h

@@ -131,6 +131,7 @@ struct rach_cfg_nr_t {
   uint32_t powerRampingStep;
   uint32_t ra_responseWindow;
   uint32_t ra_ContentionResolutionTimer;
+  uint32_t nof_preambles;
 
   rach_cfg_nr_t() { reset(); }
   void reset()
@@ -140,6 +141,7 @@ struct rach_cfg_nr_t {
     powerRampingStep            = 0;
     preambleTransMax            = 0;
     ra_responseWindow           = 0;
+    nof_preambles               = 0;
   }
 };
 

lib/src/asn1/rrc_nr_utils.cc

@@ -97,6 +97,10 @@ void make_mac_rach_cfg(const rach_cfg_common_s& asn1_type, rach_cfg_nr_t* rach_c
   rach_cfg_nr->PreambleReceivedTargetPower  = asn1_type.rach_cfg_generic.preamb_rx_target_pwr;
   rach_cfg_nr->preambleTransMax             = asn1_type.rach_cfg_generic.preamb_trans_max.to_number();
   rach_cfg_nr->ra_ContentionResolutionTimer = asn1_type.ra_contention_resolution_timer.to_number();
+
+  if (asn1_type.total_nof_ra_preambs_present) {
+    rach_cfg_nr->nof_preambles = asn1_type.total_nof_ra_preambs;
+  }
 };
 
 int make_rlc_config_t(const rlc_cfg_c& asn1_type, uint8_t bearer_id, rlc_config_t* cfg_out)

srsue/hdr/stack/mac_nr/proc_ra_nr.h

@@ -29,7 +29,7 @@ class proc_ra_nr
 {
 public:
   proc_ra_nr(mac_interface_proc_ra_nr& mac_, srslog::basic_logger& logger_);
-  ~proc_ra_nr(){};
+  ~proc_ra_nr() { srsran_random_free(random_gen); };
 
   void init(phy_interface_mac_nr* phy_h_, srsran::ext_task_sched_handle* task_sched_);
   void set_config(const srsran::rach_cfg_nr_t& rach_cfg_nr);
@@ -57,8 +57,10 @@ private:
       16 * 10; ///< Limited from frame system number opportunity period in TS 38.211 tables 6.3.3.2-2, 6.3.3.2-3
                ///< and 6.3.3.2-4
 
-  mac_interface_proc_ra_nr&             mac;
-  srslog::basic_logger&                 logger;
+  mac_interface_proc_ra_nr& mac;
+  srslog::basic_logger&     logger;
+  srsran_random_t           random_gen;
+
   phy_interface_mac_nr*                 phy        = nullptr;
   srsran::ext_task_sched_handle*        task_sched = nullptr;
   srsran::task_multiqueue::queue_handle task_queue;

srsue/hdr/stack/rrc_nr/rrc_nr.h

@@ -166,6 +166,8 @@ private:
   bool                           running = false;
   srsran::block_queue<cmd_msg_t> cmd_q;
 
+  srsran_random_t random_gen;
+
   // PHY config
   srsran::phy_cfg_nr_t phy_cfg = {};
 

srsue/src/stack/mac_nr/proc_ra_nr.cc

@@ -41,6 +41,10 @@ void proc_ra_nr::init(phy_interface_mac_nr* phy_, srsran::ext_task_sched_handle*
   rar_timeout_timer           = task_sched->get_unique_timer();
   contention_resolution_timer = task_sched->get_unique_timer();
   backoff_timer               = task_sched->get_unique_timer();
+
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  random_gen = srsran_random_init(tv.tv_usec);
 }
 
 /* Sets a new configuration. The configuration is applied by initialization() function */
@@ -166,7 +170,11 @@ void proc_ra_nr::ra_preamble_transmission()
   preamble_received_target_power = rach_cfg.PreambleReceivedTargetPower + delta_preamble +
                                    (preamble_transmission_counter - 1) * rach_cfg.powerRampingStep +
                                    power_offset_2step_ra;
-  preamble_index = 0;
+  if (rach_cfg.nof_preambles) {
+    preamble_index = srsran_random_uniform_int_dist(random_gen, 0, rach_cfg.nof_preambles);
+  } else {
+    preamble_index = 0;
+  }
   prach_occasion = 0;
   // instruct the physical layer to transmit the Random Access Preamble using the selected PRACH occasion, corresponding
   // RA-RNTI (if available), PREAMBLE_INDEX, and PREAMBLE_RECEIVED_TARGET_POWER.

srsue/src/stack/rrc_nr/rrc_nr.cc

@@ -36,10 +36,16 @@ rrc_nr::rrc_nr(srsran::task_sched_handle task_sched_) :
   cell_selector(*this),
   meas_cells(task_sched_)
 {
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  random_gen = srsran_random_init(tv.tv_usec);
   set_phy_default_config();
 }
 
-rrc_nr::~rrc_nr() = default;
+rrc_nr::~rrc_nr()
+{
+  srsran_random_free(random_gen);
+}
 
 int rrc_nr::init(phy_interface_rrc_nr*       phy_,
                  mac_interface_rrc_nr*       mac_,
@@ -601,8 +607,7 @@ void rrc_nr::send_setup_request(srsran::nr_establishment_cause_t cause)
 
   // 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;
+  uint64_t random_id = srsran_random_uniform_int_dist(random_gen, 0, 12345);
   for (uint i = 0; i < 5; i++) { // fill random ID bytewise, 40 bits = 5 bytes
     random_id |= ((uint64_t)rand() & 0xFF) << i * 8;
   }