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hodec2: fix low rxqual tch/h<->tch/f oscillation 

Related: SYS#5198
Change-Id: I96cd5a494e661ba3bb0b6d22d25a9968d2a6813c
This commit is contained in:
Neels Hofmeyr 2021-06-29 15:33:13 +02:00
parent 4011c54620
commit c44a27c672
2 changed files with 13 additions and 11 deletions
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13
src/osmo-bsc/handover_decision_2.c
View File

@ -265,6 +265,15 @@ static bool is_low_rxlev(int rxlev_current, struct handover_cfg *neigh_cfg)
&& rxlev2dbm(rxlev_current) < ho_get_hodec2_min_rxlev(neigh_cfg);
}
static bool is_low_rxqual(int rxqual_current, struct handover_cfg *neigh_cfg)
{
/* min_rxqual is actually a bit of a misnomer, low quality is a high number. So the "min" refers to the minimum
* acceptable level of quality, and "min or better" here means "rxqual number must be SMALLER-or-equal than the
* min-rxqual setting". */
return rxqual_current >= 0
&& rxqual_current > ho_get_hodec2_min_rxqual(neigh_cfg);
}
/* obtain averaged rxlev for given neighbor */
static int neigh_meas_avg(struct neigh_meas_proc *nmp, int window)
{
@ -1203,7 +1212,9 @@ static void collect_candidates_for_lchan(struct gsm_lchan *lchan,
/* See if re-assignment within the same cell can resolve congestion.
* But: when TCH/F has low rxlev, do not re-assign. If a low rxlev TCH/F were re-assigned to TCH/H, we would
* subsequently oscillate back to TCH/F due to low rxlev. So skip TCH/F with low rxlev. */
if (assignment && !(lchan->type == GSM_LCHAN_TCH_F && is_low_rxlev(rxlev_current, bts->ho)))
if (assignment
&& !(lchan->type == GSM_LCHAN_TCH_F
&& (is_low_rxlev(rxlev_current, bts->ho) || is_low_rxqual(current_rxqual(lchan), bts->ho))))
collect_assignment_candidate(lchan, clist, candidates, rxlev_current);
if (handover) {

11
tests/handover/test_amr_tch_h_to_f_rxqual_oscillation.ho_vty
View File

@ -17,13 +17,4 @@ expect-ts-use trx 0 0 states * TCH/F - - - - - *
meas-rep lchan 0 0 1 0 rxlev 30 rxqual 6 ta 0
congestion-check
# FAIL: should stay on TCH/F because rxqual is low, do not oscillate between TCH/F and /H.
expect-as from lchan 0 0 1 0 to lchan 0 0 4 0
expect-ts-use trx 0 0 states * - - - TCH/H- - - *
meas-rep lchan 0 0 4 0 rxlev 30 rxqual 6 ta 0
expect-as from lchan 0 0 4 0 to lchan 0 0 1 0
expect-ts-use trx 0 0 states * TCH/F - - - - - *
meas-rep lchan 0 0 1 0 rxlev 30 rxqual 6 ta 0
congestion-check
expect-as from lchan 0 0 1 0 to lchan 0 0 4 0
expect-ts-use trx 0 0 states * - - - TCH/H- - - *
expect-no-chan