neels has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-bsc/+/27596 )
Change subject: hodec2: add penalty-time low-rxqual-ho
......................................................................
hodec2: add penalty-time low-rxqual-ho
When bad RxQual causes handover to a cell with weaker RxLev, then
handover oscillation *will* happen, as shown in test_rxqual.ho_vty.
Introduce a penalty timer for a cell where we had bad RxQual.
This delays handover back to the cell with stronger RxLev by the penalty
timeout; hopefully the interference is gone after the timeout.
Related: SYS#5911
Change-Id: I057b156604a104a26a7ce45d1c7adadbf452c932
---
M include/osmocom/bsc/handover_cfg.h
M src/osmo-bsc/handover_decision_2.c
M tests/handover/test_rxqual.ho_vty
3 files changed, 41 insertions(+), 1 deletion(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/96/27596/1
diff --git a/include/osmocom/bsc/handover_cfg.h b/include/osmocom/bsc/handover_cfg.h
index 2bd2681..7d68e63 100644
--- a/include/osmocom/bsc/handover_cfg.h
+++ b/include/osmocom/bsc/handover_cfg.h
@@ -268,6 +268,13 @@
"Time to suspend re-assignment after an lchan was re-assigned because of low RxQual\n" \
"Seconds\n") \
\
+ HO_CFG_ONE_MEMBER(int, hodec2_penalty_low_rxqual_ho, 60, \
+ "handover2 ", "penalty-time low-rxqual-ho", "<0-99999>", atoi, "%d", as_is, \
+ HO_CFG_STR_HANDOVER2 \
+ HO_CFG_STR_PENALTY_TIME \
+ "Time to suspend handover back to a cell after bad RxQual caused handover away from it\n" \
+ "Seconds\n") \
+ \
HO_CFG_ONE_MEMBER(int, hodec2_retries, 0, \
"handover2 ", "retries", "<0-9>", atoi, "%d", as_is, \
HO_CFG_STR_HANDOVER2 \
diff --git a/src/osmo-bsc/handover_decision_2.c b/src/osmo-bsc/handover_decision_2.c
index 14bc2d4..8627910 100644
--- a/src/osmo-bsc/handover_decision_2.c
+++ b/src/osmo-bsc/handover_decision_2.c
@@ -914,6 +914,19 @@
full_rate ? "TCH/F" : "TCH/H",
ho_reason_name(global_ho_reason));
handover_request(&req);
+
+ /* Apply penalty timer hodec2_penalty_low_rxqual_ho */
+ if (global_ho_reason == HO_REASON_INTERFERENCE
+ || global_ho_reason == HO_REASON_BAD_QUALITY) {
+ struct gsm0808_cell_id bts_id;
+ struct gsm_subscriber_connection *conn = c->current.lchan->conn;
+ int timeout = ho_get_hodec2_penalty_low_rxqual_ho(c->current.bts->ho);
+ gsm_bts_cell_id(&bts_id, c->current.bts);
+ LOGPHOCAND(c, LOGL_DEBUG, "Applying penalty-time low-rxqual-ho %d s on bts %u (%s), reason: %s\n",
+ timeout, c->current.bts->nr, gsm0808_cell_id_name_c(OTC_SELECT, &bts_id),
+ ho_reason_name(global_ho_reason));
+ penalty_timers_add(conn, &conn->hodec2.penalty_timers, &bts_id, timeout);
+ }
}
return 0;
}
diff --git a/tests/handover/test_rxqual.ho_vty b/tests/handover/test_rxqual.ho_vty
index f64de52..6f86cf4 100644
--- a/tests/handover/test_rxqual.ho_vty
+++ b/tests/handover/test_rxqual.ho_vty
@@ -10,6 +10,10 @@
# See Performance Enhancements in a Frequency Hopping GSM Network (Nielsen Wigard 2002), Chapter
# 2.1.1, "Interference" in the list of triggers on p.157.
+# first show undesired oscillation when penalty-time low-rxqual-ho is disabled
+network
+ handover2 penalty-time low-rxqual-ho 0
+
create-n-bts 2
set-ts-use trx 0 0 states * TCH/F - - - - - -
meas-rep repeat 9 lchan 0 0 1 0 rxlev 40 rxqual 6 ta 0 neighbors 30
@@ -20,10 +24,26 @@
expect-ts-use trx 1 0 states * TCH/F - - - - - -
# Now the channel is on bts 1, which has lower rxlev than bts 0.
-# The result is an undesired ho oscillation
+# The result is an undesired ho oscillation, because the penalty timer is zero
meas-rep lchan 1 0 1 0 rxlev 30 rxqual 0 ta 0 neighbors 40
expect-ho from lchan 1 0 1 0 to lchan 0 0 1 0
+
+# Set a proper penalty timeout and report bad-rxqual again
+network
+ handover2 penalty-time low-rxqual-ho 10
meas-rep repeat 10 lchan 0 0 1 0 rxlev 40 rxqual 6 ta 0 neighbors 30
expect-ho from lchan 0 0 1 0 to lchan 1 0 1 0
+
+# This time the penalty timer prevents oscillation
+meas-rep repeat 10 lchan 1 0 1 0 rxlev 30 rxqual 0 ta 0 neighbors 40
+expect-no-chan
+
+# After the penalty timeout passes, we do go back to the cell with stronger rxlev
+wait 10
meas-rep lchan 1 0 1 0 rxlev 30 rxqual 0 ta 0 neighbors 40
expect-ho from lchan 1 0 1 0 to lchan 0 0 1 0
+# If the rxqual is still bad here after the penalty timeout, well, then we quickly snap back to the weaker cell, once
+meas-rep repeat 10 lchan 0 0 1 0 rxlev 40 rxqual 6 ta 0 neighbors 30
+expect-ho from lchan 0 0 1 0 to lchan 1 0 1 0
+meas-rep repeat 10 lchan 1 0 1 0 rxlev 30 rxqual 0 ta 0 neighbors 40
+expect-no-chan
--
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: I057b156604a104a26a7ce45d1c7adadbf452c932
Gerrit-Change-Number: 27596
Gerrit-PatchSet: 1
Gerrit-Owner: neels <nhofmeyr(a)sysmocom.de>
Gerrit-MessageType: newchange
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Hello Jenkins Builder, fixeria,
I'd like you to reexamine a change. Please visit
https://gerrit.osmocom.org/c/osmo-bsc/+/27595
to look at the new patch set (#2).
Change subject: hodec2: show reported ho oscillation from bad rxqual
......................................................................
hodec2: show reported ho oscillation from bad rxqual
First show the problem.
Related: SYS#5911
Change-Id: I51f3101901492ae742d8e56d6eed2725408216cb
---
M tests/handover/test_rxqual.ho_vty
1 file changed, 8 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/95/27595/2
--
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Gerrit-Change-Number: 27595
Gerrit-PatchSet: 2
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fixeria has posted comments on this change. ( https://gerrit.osmocom.org/c/osmo-bsc/+/27595 )
Change subject: hodec2: reproduce reported ho oscillation from bad rxqual
......................................................................
Patch Set 1: Code-Review+2
--
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Gerrit-Branch: master
Gerrit-Change-Id: I51f3101901492ae742d8e56d6eed2725408216cb
Gerrit-Change-Number: 27595
Gerrit-PatchSet: 1
Gerrit-Owner: neels <nhofmeyr(a)sysmocom.de>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <vyanitskiy(a)sysmocom.de>
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Gerrit-Comment-Date: Mon, 28 Mar 2022 20:45:23 +0000
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laforge has submitted this change. ( https://gerrit.osmocom.org/c/osmo-bsc/+/27590 )
Change subject: SMSCB: Preserve padding at end of page in CBSP -> RSL conversion
......................................................................
SMSCB: Preserve padding at end of page in CBSP -> RSL conversion
When copying the CBS page content from CBSP to RSL data structures, we
use the User Information Length as length argument in the memcpy. The
logic for that is that only this part of the message contains valid
data.
However, as the user information length is not passed on via RSL or
transmitted over the air, the receiving MS will get a page with
zero-initialized padding, rather than whatever the originator of the
message has specified. As zero bytes in the 8bit domain might get
translated into @-characters in the 7bit domain, this creates problems.
So instead, let's always copy the entire page (82 bytes) to ensure
transparency when passing on information from CBSP to RSL.
Change-Id: Iffcf1f6a7d41a08a2feffc6f2ac5634d940b63aa
Closes: SYS#5904
---
M src/osmo-bsc/smscb.c
1 file changed, 7 insertions(+), 1 deletion(-)
Approvals:
Jenkins Builder: Verified
pespin: Looks good to me, approved
diff --git a/src/osmo-bsc/smscb.c b/src/osmo-bsc/smscb.c
index 542453c..1640880 100644
--- a/src/osmo-bsc/smscb.c
+++ b/src/osmo-bsc/smscb.c
@@ -22,6 +22,7 @@
#include <limits.h>
#include <osmocom/core/stats.h>
+#include <osmocom/core/utils.h>
#include <osmocom/core/select.h>
#include <osmocom/core/msgb.h>
#include <osmocom/core/talloc.h>
@@ -384,6 +385,9 @@
page = &smscb->page[i++];
msg_param = (struct gsm23041_msg_param_gsm *) &page->data[0];
+ /* ensure we don't overflow in the memcpy below */
+ osmo_static_assert(sizeof(*page) > sizeof(*msg_param) + sizeof(cont->data), smscb_space);
+
/* build 6 byte header according to TS 23.041 9.4.1.2 */
osmo_store16be(wrepl->new_serial_nr, &msg_param->serial_nr);
osmo_store16be(wrepl->msg_id, &msg_param->message_id);
@@ -393,7 +397,9 @@
OSMO_ASSERT(cont->user_len <= ARRAY_SIZE(cont->data));
OSMO_ASSERT(cont->user_len <= ARRAY_SIZE(page->data) - sizeof(*msg_param));
- memcpy(&msg_param->content, cont->data, cont->user_len);
+ /* we must not use cont->user_len as length here, as it would truncate any
+ * possible 7-bit padding at the end. Always copy the whole page */
+ memcpy(&msg_param->content, cont->data, sizeof(cont->data));
bytes_used = sizeof(*msg_param) + cont->user_len;
/* compute number of valid blocks in page */
page->num_blocks = bytes_used / 22;
--
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: Iffcf1f6a7d41a08a2feffc6f2ac5634d940b63aa
Gerrit-Change-Number: 27590
Gerrit-PatchSet: 2
Gerrit-Owner: laforge <laforge(a)osmocom.org>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <vyanitskiy(a)sysmocom.de>
Gerrit-Reviewer: laforge <laforge(a)osmocom.org>
Gerrit-Reviewer: neels <nhofmeyr(a)sysmocom.de>
Gerrit-Reviewer: pespin <pespin(a)sysmocom.de>
Gerrit-MessageType: merged