Make nr_find_nb_rb() take minimum RBsize

Fixes a bug when scheduling multiple UEs

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c

@@ -598,6 +598,7 @@ bool allocate_dl_retransmission(module_id_t module_id,
                                  temp_ps.nrOfSymbols,
                                  temp_ps.N_PRB_DMRS * temp_ps.N_DMRS_SLOT,
                                  retInfo->tb_size,
+                                 1, /* minimum of 1RB: need to find exact TBS, don't preclude any number */
                                  rbSize,
                                  &new_tbs,
                                  &new_rbSize);
@@ -739,8 +740,9 @@ void pf_dl(module_id_t module_id,
     }
   }
 
+  const int min_rbSize = 5;
   /* Loop UE_sched to find max coeff and allocate transmission */
-  while (max_num_ue > 0 && n_rb_sched > 0 && UE_sched.head >= 0) {
+  while (max_num_ue > 0 && n_rb_sched >= min_rbSize && UE_sched.head >= 0) {
 
     /* Find max coeff from UE_sched*/
     int *max = &UE_sched.head; /* assume head is max */
@@ -859,6 +861,7 @@ void pf_dl(module_id_t module_id,
                   ps->nrOfSymbols,
                   ps->N_PRB_DMRS * ps->N_DMRS_SLOT,
                   sched_ctrl->num_total_bytes + oh,
+                  min_rbSize,
                   max_rbSize,
                   &TBS,
                   &rbSize);

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c

@@ -388,6 +388,7 @@ bool nr_find_nb_rb(uint16_t Qm,
                    uint16_t nb_symb_sch,
                    uint16_t nb_dmrs_prb,
                    uint32_t bytes,
+                   uint16_t nb_rb_min,
                    uint16_t nb_rb_max,
                    uint32_t *tbs,
                    uint16_t *nb_rb)
@@ -403,7 +404,7 @@ bool nr_find_nb_rb(uint16_t Qm,
     return true;
 
   /* is the minimum enough? */
-  *nb_rb = 5;
+  *nb_rb = nb_rb_min;
   *tbs = nr_compute_tbs(Qm, R, *nb_rb, nb_symb_sch, nb_dmrs_prb, 0, 0, 1) >> 3;
   if (bytes <= *tbs)
     return true;
@@ -411,7 +412,7 @@ bool nr_find_nb_rb(uint16_t Qm,
   /* perform binary search to allocate all bytes within a TBS up to nb_rb_max
    * RBs */
   int hi = nb_rb_max;
-  int lo = 1;
+  int lo = nb_rb_min;
   for (int p = (hi + lo) / 2; lo + 1 < hi; p = (hi + lo) / 2) {
     const uint32_t TBS = nr_compute_tbs(Qm, R, p, nb_symb_sch, nb_dmrs_prb, 0, 0, 1) >> 3;
     if (bytes == TBS) {

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c

@@ -1004,6 +1004,7 @@ bool allocate_ul_retransmission(module_id_t module_id,
                                  temp_ps.nrOfSymbols,
                                  temp_ps.N_PRB_DMRS * temp_ps.num_dmrs_symb,
                                  retInfo->tb_size,
+                                 1, /* minimum of 1RB: need to find exact TBS, don't preclude any number */
                                  rbSize,
                                  &new_tbs,
                                  &new_rbSize);
@@ -1256,8 +1257,9 @@ void pf_ul(module_id_t module_id,
   }
 
 
+  const int min_rbSize = 5;
   /* Loop UE_sched to find max coeff and allocate transmission */
-  while (UE_sched.head >= 0 && max_num_ue> 0 && n_rb_sched > 0) {
+  while (UE_sched.head >= 0 && max_num_ue> 0 && n_rb_sched >= min_rbSize) {
     /* Find max coeff */
     int *max = &UE_sched.head; /* Find max coeff: assume head is max */
     int *p = &UE_sched.next[*max];
@@ -1349,6 +1351,7 @@ void pf_ul(module_id_t module_id,
                   ps->nrOfSymbols,
                   ps->N_PRB_DMRS * ps->num_dmrs_symb,
                   B,
+                  min_rbSize,
                   max_rbSize,
                   &TBS,
                   &rbSize);

openair2/LAYER2/NR_MAC_gNB/mac_proto.h

@@ -463,6 +463,7 @@ bool nr_find_nb_rb(uint16_t Qm,
                    uint16_t nb_symb_sch,
                    uint16_t nb_dmrs_prb,
                    uint32_t bytes,
+                   uint16_t nb_rb_min,
                    uint16_t nb_rb_max,
                    uint32_t *tbs,
                    uint16_t *nb_rb);