avoid using PUCCH for SCell DL allocations

srsenb/src/stack/mac/scheduler_grid.cc

@@ -758,19 +758,23 @@ alloc_outcome_t sf_sched::alloc_dl_user(sched_ue* user, const rbgmask_t& user_ma
   const srslte_cqi_report_cfg_t&   cqi_report = ue_cfg.dl_cfg.cqi_report;
   if (has_scells and srslte_cqi_periodic_send(&cqi_report, get_tti_tx_ul(), SRSLTE_FDD)) {
     bool has_pusch_grant = is_ul_alloc(user) or cc_results->is_ul_alloc(user->get_rnti());
-    bool has_dl_allocs   = cc_results->is_dl_alloc(user->get_rnti());
-    if (not has_pusch_grant and has_dl_allocs) {
-      // Try to allocate small PUSCH grant, if there are no pending UL retxs
+    if (not has_pusch_grant) {
+      // Try to allocate small PUSCH grant, if there are no pending UL retxs for this TTI
+      alloc_outcome_t pusch_alloc_outcome = alloc_outcome_t::PUCCH_COLLISION;
       ul_harq_proc*   hul                 = user->get_ul_harq(get_tti_tx_ul(), ue_cc_idx);
       bool            has_retx            = hul->has_pending_retx();
       if (not has_retx) {
         ul_harq_proc::ul_alloc_t alloc = {};
         uint32_t L = user->get_required_prb_ul(ue_cc_idx, srslte::ceil_div(SRSLTE_UCI_CQI_CODED_PUCCH_B + 2, 8));
         tti_alloc.find_ul_alloc(L, &alloc);
-        if (alloc.L == 0 or not alloc_ul_user(user, alloc)) {
-          return alloc_outcome_t::PUCCH_COLLISION;
+        if (alloc.L > 0 and alloc_ul_user(user, alloc)) {
+          pusch_alloc_outcome = alloc_outcome_t::SUCCESS;
         }
       }
+      // For SCells, if we can't allocate small PUSCH grant, abort DL allocation
+      if (ue_cc_idx != 0 and pusch_alloc_outcome != alloc_outcome_t::SUCCESS) {
+        return pusch_alloc_outcome;
+      }
     }
   }