diff options
| author | Neels Hofmeyr <neels@hofmeyr.de> | 2021-01-28 15:28:51 +0100 |
|---|---|---|
| committer | Neels Hofmeyr <neels@hofmeyr.de> | 2021-02-02 21:53:53 +0100 |
| commit | b4364a4adc5322181b2d0975290fc6a9d7f88aed (patch) | |
| tree | 20e7f41c07c2f80c600575bd0a20268220f26ced /src/osmo-bsc/handover_decision_2.c | |
| parent | 1475aac8ed1b7e6dca09dbd5d75a9c0e77289846 (diff) | |
hodec2: fix intra-cell congestion balancing with source lchan on dyn TS
Related: SYS#5301
Change-Id: I332477cbddf32cf6f057007b45cda8477227f0b1
Diffstat (limited to 'src/osmo-bsc/handover_decision_2.c')
| -rw-r--r-- | src/osmo-bsc/handover_decision_2.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/src/osmo-bsc/handover_decision_2.c b/src/osmo-bsc/handover_decision_2.c index 0bfae9ba2..2cb7a54f3 100644 --- a/src/osmo-bsc/handover_decision_2.c +++ b/src/osmo-bsc/handover_decision_2.c @@ -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), |