cellular-infrastructure
/
osmo-bsc
mirror of https://gerrit.osmocom.org/osmo-bsc
9
0
Fork 0
Code Issues Releases Wiki Activity

hodec2: fix intra-cell congestion balancing with source lchan on dyn TS 

Related: SYS#5301
Change-Id: I332477cbddf32cf6f057007b45cda8477227f0b1
This commit is contained in:
Neels Hofmeyr 2021-01-28 15:28:51 +01:00
parent 1475aac8ed
commit b4364a4adc
3 changed files with 34 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
src/osmo-bsc/handover_decision_2.c
View File

@ -682,7 +682,18 @@ static void check_requirements(struct ho_candidate *c)
current_overbooked = load_above_congestion(c->current.free_tch, c->current.min_free_tch);
if (requirement & REQUIREMENT_A_TCHF) {
bool ok;
int32_t target_overbooked = load_above_congestion(c->target.free_tchf - 1, c->target.min_free_tchf);
int32_t target_overbooked;
int target_free_tchf_after_ho;
/* To evaluate whether a handover improves or worsens congestion on TCH/F, first figure out how many
* TCH/F lchans will be occupied on the target after the handover. If the target is a different cell,
* then we obviously reduce by one TCH/F. If source and target cell are the same (re-assignment), then
* the source lchan may also free a TCH/F at the same time. Add up all of these effects to figure out
* the congestion percentages before and after handover. */
target_free_tchf_after_ho = c->target.free_tchf - 1;
if (c->current.bts == c->target.bts)
target_free_tchf_after_ho += c->current.lchan_frees_tchf;
target_overbooked = load_above_congestion(target_free_tchf_after_ho, c->target.min_free_tchf);
LOGPHOLCHANTOBTS(c->current.lchan, c->target.bts, LOGL_DEBUG,
"current overbooked = %s%%, TCH/F target overbooked after HO = %s%%\n",
osmo_int_to_float_str_c(OTC_SELECT, current_overbooked, LOAD_PRECISION - 2),
@ -718,7 +729,18 @@ static void check_requirements(struct ho_candidate *c)
}
if (requirement & REQUIREMENT_A_TCHH) {
bool ok;
int32_t target_overbooked = load_above_congestion(c->target.free_tchh - 1, c->target.min_free_tchh);
int32_t target_overbooked;
int target_free_tchh_after_ho;
/* To evaluate whether a handover improves or worsens congestion on TCH/H, first figure out how many
* TCH/H lchans will be occupied on the target after the handover. If the target is a different cell,
* then we obviously reduce by one TCH/H. If source and target cell are the same (re-assignment), then
* the source lchan may also free one or two TCH/H at the same time. Add up all of these effects to
* figure out the congestion percentages before and after handover. */
target_free_tchh_after_ho = c->target.free_tchh - 1;
if (c->current.bts == c->target.bts)
target_free_tchh_after_ho += c->current.lchan_frees_tchh;
target_overbooked = load_above_congestion(target_free_tchh_after_ho, c->target.min_free_tchh);
LOGPHOLCHANTOBTS(c->current.lchan, c->target.bts, LOGL_DEBUG,
"current overbooked = %s%%, TCH/H target overbooked after HO = %s%%\n",
osmo_int_to_float_str_c(OTC_SELECT, current_overbooked, LOAD_PRECISION - 2),

18
tests/handover/test_dyn_ts_amr_tch_f_to_h_congestion_assignment_2.ho_vty
View File

@ -14,16 +14,15 @@ set-ts-use trx 0 0 states * TCH/F - - - * * *
# (there must be at least one measurement report on each lchan for congestion check to work)
meas-rep lchan * * * * rxlev 40 rxqual 0 ta 0 neighbors 30
congestion-check
# FAIL: after the handover from the dyn TS to TCH/H, the dyn TS has freed two TCH/H, while the static TCH/H has reduced
# the TCH/H count by one. So the resulting free slots are 3 TCH/H, which means no congestion. A handover should occur.
expect-no-chan
expect-ho from lchan 0 0 1 0 to lchan 0 0 4 0
expect-ts-use trx 0 0 states * pdch - - TCH/H- * * *
# Again with one more TCH/H occupied, there will still be two free TCH/H after HO on the dyn TS
set-ts-use trx 0 0 states * TCH/F - - TCH/H- * * *
meas-rep lchan * * * * rxlev 40 rxqual 0 ta 0 neighbors 30
congestion-check
# FAIL: resulting free slots are 2 TCH/H, which means no congestion. A handover should occur.
expect-no-chan
expect-ho from lchan 0 0 1 0 to lchan 0 0 4 1
expect-ts-use trx 0 0 states * pdch - - TCH/HH * * *
# Again, with the target being a dyn TS
create-bts trx-count 1 timeslots c+s4 dyn TCH/F TCH/F dyn PDCH PDCH PDCH
@ -37,13 +36,12 @@ network
set-ts-use trx 1 0 states * TCH/F TCH/F - pdch * * *
meas-rep lchan 1 * * * rxlev 40 rxqual 0 ta 0 neighbors 30
congestion-check
# FAIL: after the handover from the dyn TS to TCH/H, the dyn TS has freed two TCH/H, while the static TCH/H has reduced
# the TCH/H count by one. So the resulting free slots are 3 TCH/H, which means no congestion. A handover should occur.
expect-no-chan
expect-ho from lchan 1 0 1 0 to lchan 1 0 4 0
expect-ts-use trx 1 0 states * pdch TCH/F - TCH/H- * * *
# Again with one more TCH/H occupied, there will still be two free TCH/H after HO on the dyn TS
set-ts-use trx 1 0 states * TCH/F TCH/F - TCH/H- * * *
meas-rep lchan 1 * * * rxlev 40 rxqual 0 ta 0 neighbors 30
congestion-check
# FAIL: resulting free slots are 2 TCH/H, which means no congestion. A handover should occur.
expect-no-chan
expect-ho from lchan 1 0 1 0 to lchan 1 0 4 1
expect-ts-use trx 1 0 states * pdch TCH/F - TCH/HH * * *

5
tests/handover/test_dyn_ts_amr_tch_h_to_f_congestion_assignment_2.ho_vty
View File

@ -21,8 +21,7 @@ expect-ts-use trx 0 0 states * pdch TCH/F - - * * *
set-ts-use trx 0 0 states * TCH/H- - - TCH/F * * *
meas-rep lchan * * * * rxlev 40 rxqual 0 ta 0 neighbors 30
congestion-check
# FAIL: after the handover from the dyn TS to TCH/F, the dyn TS has freed a TCH/F, while the static TCH/F has reduced
# the TCH/F count by one. So the resulting free slots are 2 TCH/F, which means no congestion. A handover should occur.
expect-no-chan
expect-ho from lchan 0 0 1 0 to lchan 0 0 2 0
expect-ts-use trx 0 0 states * pdch TCH/F - TCH/F * * *
# (TCH/H -> TCH/F onto a dyn TS will always make TCH/H congestion worse, so there is no useful test case left here)