From 6bf0f98e7fb0c3217fb06b761e3896d8a6716e9e Mon Sep 17 00:00:00 2001
From: Robert Schmidt <robert.schmidt@openairinterface.org>
Date: Thu, 18 Aug 2022 19:59:50 +0200
Subject: [PATCH] Skip scheduling of UEs if there are no free HARQs
---
openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c | 8 ++++++++
openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c | 9 +++++++++
2 files changed, 17 insertions(+)
diff --git a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c
index 6aee81fa672..a35c80b95a6 100644
--- a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c
+++ b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c
@@ -613,6 +613,14 @@ void pf_dl(module_id_t module_id,
return;
} else {
+ /* skip this UE if there are no free HARQ processes. This can happen e.g.
+ * if the UE disconnected in L2sim, in which case the gNB is not notified
+ * (this can be considered a design flaw) */
+ if (sched_ctrl->available_dl_harq.head < 0) {
+ LOG_D(NR_MAC, "RNTI %04x has no free DL HARQ process, skipping\n", UE->rnti);
+ continue;
+ }
+
/* Check DL buffer and skip this UE if no bytes and no TA necessary */
if (sched_ctrl->num_total_bytes == 0 && frame != (sched_ctrl->ta_frame + 10) % 1024)
continue;
diff --git a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c
index 43e88eb9a94..1ca9fa067e1 100644
--- a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c
+++ b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c
@@ -1085,6 +1085,15 @@ void pf_ul(module_id_t module_id,
continue;
}
+
+ /* skip this UE if there are no free HARQ processes. This can happen e.g.
+ * if the UE disconnected in L2sim, in which case the gNB is not notified
+ * (this can be considered a design flaw) */
+ if (sched_ctrl->available_ul_harq.head < 0) {
+ LOG_D(NR_MAC, "RNTI %04x has no free UL HARQ process, skipping\n", UE->rnti);
+ continue;
+ }
+
const int B = max(0, sched_ctrl->estimated_ul_buffer - sched_ctrl->sched_ul_bytes);
/* preprocessor computed sched_frame/sched_slot */
const bool do_sched = nr_UE_is_to_be_scheduled(scc, 0, UE, sched_pusch->frame, sched_pusch->slot, nrmac->ulsch_max_frame_inactivity);
--
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