nr: hack to remove UE data in gNB's PHY

Some data remains in the PHY of the gNB after UE removal by
upper layers. After some connection/deconnection/reconnection
the gNB will exit because there is no free space in PHY.

This commit adds some global variables shared by MAC and PHY.
The function mac_remove_nr_ue puts UEs to be removed in it
and the function rxtx removes what needs to be removed.

This is a hack. It will be removed at some point in time.

The real way to remove in the PHY should be to release
data after some time of inactivity in the PHY, which would
mean the UE has been removed in upper layers. Kind of
timer-based thing. There should be no communication between
PHY and MAC.

executables/nr-gnb.c

@@ -177,6 +177,59 @@ static inline int rxtx(PHY_VARS_gNB *gNB, int frame_rx, int slot_rx, int frame_t
 
   T(T_GNB_PHY_DL_TICK, T_INT(gNB->Mod_id), T_INT(frame_tx), T_INT(slot_tx));
 
+  /* hack to remove UEs */
+  extern int rnti_to_remove[10];
+  extern volatile int rnti_to_remove_count;
+  extern pthread_mutex_t rnti_to_remove_mutex;
+  if (pthread_mutex_lock(&rnti_to_remove_mutex)) exit(1);
+  int up_removed = 0;
+  int down_removed = 0;
+  int pucch_removed = 0;
+  for (int i = 0; i < rnti_to_remove_count; i++) {
+    LOG_W(PHY, "to remove rnti %d\n", rnti_to_remove[i]);
+    void clean_gNB_ulsch(NR_gNB_ULSCH_t *ulsch);
+    void clean_gNB_dlsch(NR_gNB_DLSCH_t *dlsch);
+    int j;
+    for (j = 0; j < NUMBER_OF_NR_ULSCH_MAX; j++)
+      if (gNB->ulsch[j][0]->rnti == rnti_to_remove[i]) {
+        gNB->ulsch[j][0]->rnti = 0;
+        gNB->ulsch[j][0]->harq_mask = 0;
+        //clean_gNB_ulsch(gNB->ulsch[j][0]);
+        int h;
+        for (h = 0; h < NR_MAX_ULSCH_HARQ_PROCESSES; h++) {
+          gNB->ulsch[j][0]->harq_processes[h]->status = SCH_IDLE;
+          gNB->ulsch[j][0]->harq_processes[h]->round  = 0;
+          gNB->ulsch[j][0]->harq_processes[h]->handled = 0;
+        }
+        up_removed++;
+      }
+    for (j = 0; j < NUMBER_OF_NR_DLSCH_MAX; j++)
+      if (gNB->dlsch[j][0]->rnti == rnti_to_remove[i]) {
+        gNB->dlsch[j][0]->rnti = 0;
+        gNB->dlsch[j][0]->harq_mask = 0;
+        //clean_gNB_dlsch(gNB->dlsch[j][0]);
+        down_removed++;
+      }
+    for (j = 0; j < NUMBER_OF_NR_PUCCH_MAX; j++)
+      if (gNB->pucch[j]->active > 0 &&
+          gNB->pucch[j]->pucch_pdu.rnti == rnti_to_remove[i]) {
+        gNB->pucch[j]->active = 0;
+        gNB->pucch[j]->pucch_pdu.rnti = 0;
+        pucch_removed++;
+      }
+#if 0
+    for (j = 0; j < NUMBER_OF_NR_PDCCH_MAX; j++)
+      gNB->pdcch_pdu[j].frame = -1;
+    for (j = 0; j < NUMBER_OF_NR_PDCCH_MAX; j++)
+      gNB->ul_pdcch_pdu[j].frame = -1;
+    for (j = 0; j < NUMBER_OF_NR_PRACH_MAX; j++)
+      gNB->prach_vars.list[j].frame = -1;
+#endif
+  }
+  if (rnti_to_remove_count) LOG_W(PHY, "to remove rnti_to_remove_count=%d, up_removed=%d down_removed=%d pucch_removed=%d\n", rnti_to_remove_count, up_removed, down_removed, pucch_removed);
+  rnti_to_remove_count = 0;
+  if (pthread_mutex_unlock(&rnti_to_remove_mutex)) exit(1);
+
   /*
   // if this is IF5 or 3GPP_gNB
   if (gNB && gNB->RU_list && gNB->RU_list[0] && gNB->RU_list[0]->function < NGFI_RAU_IF4p5) {

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c

@@ -1492,6 +1492,11 @@ int add_new_nr_ue(module_id_t mod_idP, rnti_t rntiP){
   return -1;
 }
 
+/* hack data to remove UE in the phy */
+int rnti_to_remove[10];
+volatile int rnti_to_remove_count;
+pthread_mutex_t rnti_to_remove_mutex = PTHREAD_MUTEX_INITIALIZER;
+
 void mac_remove_nr_ue(module_id_t mod_id, rnti_t rnti)
 {
   int UE_id;
@@ -1519,6 +1524,14 @@ void mac_remove_nr_ue(module_id_t mod_id, rnti_t rnti)
           mod_id,
           UE_id,
           rnti);
+
+    /* hack to remove UE in the phy */
+    if (pthread_mutex_lock(&rnti_to_remove_mutex)) exit(1);
+    if (rnti_to_remove_count == 10) exit(1);
+    rnti_to_remove[rnti_to_remove_count] = rnti;
+    LOG_W(MAC, "to remove in mac rnti_to_remove[%d]=%d\n", rnti_to_remove_count, rnti);
+    rnti_to_remove_count++;
+    if (pthread_mutex_unlock(&rnti_to_remove_mutex)) exit(1);
   }
 }