sched,optimization - considering that cfi is static for sib/rar allocations, pick from the start of the tti, the optimal CFI in terms of largest number of CCE positions available

srsenb/src/stack/mac/sched_phy_ch/sf_cch_allocator.cc

@@ -66,6 +66,21 @@ bool sf_cch_allocator::alloc_dci(alloc_type_t alloc_type, uint32_t aggr_idx, sch
   // TODO: Make the alloc tree update lazy
   alloc_record_t record{.user = user, .aggr_idx = aggr_idx, .alloc_type = alloc_type, .pusch_uci = has_pusch_grant};
 
+  if (is_dl_ctrl_alloc(alloc_type) and current_max_cfix > current_cfix) {
+    // Given that CFI is not currently dynamic for ctrl allocs, in case of SIB/RAR alloc, start with optimal CFI
+    // in terms of nof CCE locs
+    uint32_t nof_locs = 0;
+    for (uint32_t cfix_tmp = current_max_cfix; cfix_tmp > current_cfix; ++cfix_tmp) {
+      const cce_cfi_position_table* dci_locs = get_cce_loc_table(record.alloc_type, record.user, cfix_tmp);
+      if ((*dci_locs)[record.aggr_idx].size() >= nof_locs) {
+        nof_locs     = (*dci_locs)[record.aggr_idx].size();
+        current_cfix = cfix_tmp;
+      } else {
+        break;
+      }
+    }
+  }
+
   // Try to allocate user in PDCCH for given CFI. If it fails, increment CFI.
   uint32_t first_cfi = get_cfi();
   bool     success;