From 5933f21882d95ccfe5ea1420df05937615d8c2cd Mon Sep 17 00:00:00 2001
From: Cedric Roux <cedric.roux@eurecom.fr>
Date: Thu, 19 Jan 2017 10:00:19 +0100
Subject: [PATCH] hack to avoid zombie UEs in the MAC layer
Here is the problem:
Sometimes the UE has no PHY context but
is still present in the MAC with 'ul_failure_timer' = 0 and
'ul_out_of_sync' = 0. It seems wrong and the UE stays there forever. Let's
start an UL out of sync procedure in this case.
The root cause of this problem has to be found and corrected.
In the meantime, this hack...
This has to be redone at some point.
---
openair2/LAYER2/MAC/eNB_scheduler_ulsch.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/openair2/LAYER2/MAC/eNB_scheduler_ulsch.c b/openair2/LAYER2/MAC/eNB_scheduler_ulsch.c
index ec43c2434b5..6e744a52286 100644
--- a/openair2/LAYER2/MAC/eNB_scheduler_ulsch.c
+++ b/openair2/LAYER2/MAC/eNB_scheduler_ulsch.c
@@ -762,8 +762,25 @@ void schedule_ulsch_rnti(module_id_t module_idP,
break;
}
}
- if (drop_ue == 1)
+ if (drop_ue == 1) {
+ /* TODO: this is a hack. Sometimes the UE has no PHY context but
+ * is still present in the MAC with 'ul_failure_timer' = 0 and
+ * 'ul_out_of_sync' = 0. It seems wrong and the UE stays there forever. Let's
+ * start an UL out of sync procedure in this case.
+ * The root cause of this problem has to be found and corrected.
+ * In the meantime, this hack...
+ */
+ if (UE_list->UE_sched_ctrl[UE_id].ul_failure_timer == 0 &&
+ UE_list->UE_sched_ctrl[UE_id].ul_out_of_sync == 0) {
+ LOG_W(MAC,"[eNB %d] frame %d subframe %d, UE %d/%x CC %d: UE in weird state, let's put it 'out of sync'\n",
+ module_idP,frameP,subframeP,UE_id,rnti,CC_id);
+ // inform RRC of failure and clear timer
+ mac_eNB_rrc_ul_failure(module_idP,CC_id,frameP,subframeP,rnti);
+ UE_list->UE_sched_ctrl[UE_id].ul_failure_timer=0;
+ UE_list->UE_sched_ctrl[UE_id].ul_out_of_sync=1;
+ }
continue;
+ }
// loop over all active UL CC_ids for this UE
for (n=0; n<UE_list->numactiveULCCs[UE_id]; n++) {
--
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