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authorNeels Hofmeyr <neels@hofmeyr.de>2021-07-08 04:20:59 +0200
committerNeels Hofmeyr <neels@hofmeyr.de>2021-07-11 21:14:51 +0200
commit5ac70756435213783c5f6896d17d1b55ba17286c (patch)
treef3a8c9e163ec1072a628bab0f3628e59aa4fc8f7
parentf764248b032d6a5c90286a9f2a32eca381d21fee (diff)
RES IND: pick lchan with least interference
In lchan_select, do not return on the first available lchan, but iterate through all available lchans. Among those that would match, pick the one with the lowest interference level as indicated by earlier RES IND. Lchans that have no interference ratings are picked last. This feature is off by default, enable per BTS with network bts N channel allocator avoid-interference 1 osmo-bsc still does the same ascending/descending lchan allocation as before this patch with the default setting of: channel allocator avoid-interference 0 Related: SYS#5313 Change-Id: I844494092193811dfd9fa4d52983cbaed0fc9248
-rw-r--r--src/osmo-bsc/lchan_select.c59
-rw-r--r--tests/handover/test_resource_indication.ho_vty27
2 files changed, 57 insertions, 29 deletions
diff --git a/src/osmo-bsc/lchan_select.c b/src/osmo-bsc/lchan_select.c
index efa2ff29b..3618fb4e8 100644
--- a/src/osmo-bsc/lchan_select.c
+++ b/src/osmo-bsc/lchan_select.c
@@ -30,22 +30,36 @@
#include <osmocom/bsc/lchan_select.h>
#include <osmocom/bsc/bts.h>
+static struct gsm_lchan *pick_better_lchan(struct gsm_lchan *a, struct gsm_lchan *b)
+{
+ if (!a)
+ return b;
+ if (!b)
+ return a;
+ /* comparing negative dBm values: smaller value means less interference. */
+ if (b->interf_dbm < a->interf_dbm)
+ return b;
+ return a;
+}
+
static struct gsm_lchan *
_lc_find_trx(struct gsm_bts_trx *trx, enum gsm_phys_chan_config pchan,
enum gsm_phys_chan_config as_pchan, bool allow_pchan_switch, bool log)
{
struct gsm_lchan *lchan;
+ struct gsm_lchan *found_lchan = NULL;
struct gsm_bts_trx_ts *ts;
int j, start, stop, dir;
-#define LOGPLCHANALLOC(fmt, args...) \
+#define LOGPLCHANALLOC(fmt, args...) do { \
if (log) \
LOGP(DRLL, LOGL_DEBUG, "looking for lchan %s%s%s%s: " fmt, \
gsm_pchan_name(pchan), \
pchan == as_pchan ? "" : " as ", \
pchan == as_pchan ? "" : gsm_pchan_name(as_pchan), \
((pchan != as_pchan) && !allow_pchan_switch) ? " without pchan switch" : "", \
- ## args)
+ ## args); \
+ } while (0)
if (!trx_is_usable(trx)) {
LOGPLCHANALLOC("%s trx not usable\n", gsm_trx_name(trx));
@@ -87,20 +101,43 @@ _lc_find_trx(struct gsm_bts_trx *trx, enum gsm_phys_chan_config pchan,
/* TS is (going to be) in desired pchan mode. Go ahead and check for an available lchan. */
lchans_as_pchan = pchan_subslots(as_pchan);
ts_for_n_lchans(lchan, ts, lchans_as_pchan) {
- if (lchan->fi->state == LCHAN_ST_UNUSED) {
- LOGPLCHANALLOC("%s ss=%d is available%s\n",
+ struct gsm_lchan *was = found_lchan;
+
+ if (lchan->fi->state != LCHAN_ST_UNUSED) {
+ LOGPLCHANALLOC("%s ss=%d in type=%s,state=%s not suitable\n",
gsm_ts_and_pchan_name(ts), lchan->nr,
- ts->pchan_is != as_pchan ? " after dyn PCHAN change" : "");
- return lchan;
+ gsm_lchant_name(lchan->type),
+ osmo_fsm_inst_state_name(lchan->fi));
+ continue;
}
- LOGPLCHANALLOC("%s ss=%d in type=%s,state=%s not suitable\n",
- gsm_ts_and_pchan_name(ts), lchan->nr,
- gsm_lchant_name(lchan->type),
- osmo_fsm_inst_state_name(lchan->fi));
+
+ found_lchan = pick_better_lchan(found_lchan, lchan);
+ if (found_lchan != was)
+ LOGPLCHANALLOC("%s ss=%d interf=%u=%ddBm is %s%s\n",
+ gsm_ts_and_pchan_name(ts), lchan->nr,
+ lchan->interf_band, lchan->interf_dbm,
+ was == NULL ? "available" : "better",
+ ts->pchan_is != as_pchan ? ", after dyn PCHAN change" : "");
+ else
+ LOGPLCHANALLOC("%s ss=%d interf=%u=%ddBm is also available but not better\n",
+ gsm_ts_and_pchan_name(ts), lchan->nr,
+ lchan->interf_band, lchan->interf_dbm);
+
+ /* When picking an lchan with least interference, continue to loop across all lchans. When
+ * ignoring interference levels, return the first match. */
+ if (found_lchan && !trx->bts->chan_alloc_avoid_interf)
+ return found_lchan;
}
}
- return NULL;
+ if (found_lchan)
+ LOGPLCHANALLOC("%s ss=%d interf=%ddBm%s is the best pick\n",
+ gsm_ts_and_pchan_name(found_lchan->ts), found_lchan->nr,
+ found_lchan->interf_dbm,
+ found_lchan->ts->pchan_is != as_pchan ? ", after dyn PCHAN change," : "");
+ else
+ LOGPLCHANALLOC("Nothing found");
+ return found_lchan;
#undef LOGPLCHANALLOC
}
diff --git a/tests/handover/test_resource_indication.ho_vty b/tests/handover/test_resource_indication.ho_vty
index 9dd9d3851..724372ee9 100644
--- a/tests/handover/test_resource_indication.ho_vty
+++ b/tests/handover/test_resource_indication.ho_vty
@@ -12,8 +12,7 @@ network
res-ind trx 0 0 levels - 1 2 3 4 3 2 -
create-ms bts 0 TCH/F AMR
-# FAIL: interference is ignored
-expect-ts-use trx 0 0 states * TCH/F - - - - - *
+expect-ts-use trx 0 0 states * - - - TCH/F - - *
# The ordering may also be configured reversed, still the lowest dBm value should win
network
@@ -23,26 +22,22 @@ network
res-ind trx 0 0 levels - 5 4 2 - 3 4 -
create-ms bts 0 TCH/F AMR
-# FAIL: interference is ignored
-expect-ts-use trx 0 0 states * TCH/F TCH/F - - - - *
+expect-ts-use trx 0 0 states * - - TCH/F TCH/F - - *
# Favor lchans that have an indicated interference level
res-ind trx 0 0 levels - - - - - 4 3 -
create-ms bts 0 TCH/F AMR
-# FAIL: interference is ignored
-expect-ts-use trx 0 0 states * TCH/F TCH/F TCH/F - - - *
+expect-ts-use trx 0 0 states * - - TCH/F TCH/F - TCH/F *
# For equal levels, pick the first
res-ind trx 0 0 levels - 2 2 - - 2 - -
create-ms bts 0 TCH/F AMR
-# FAIL: interference is ignored
-expect-ts-use trx 0 0 states * TCH/F TCH/F TCH/F TCH/F - - *
+expect-ts-use trx 0 0 states * TCH/F - TCH/F TCH/F - TCH/F *
# Test clamping of indexes > 5
res-ind trx 0 0 levels - - 6 - - 4 - -
create-ms bts 0 TCH/F AMR
-# FAIL: interference is ignored
-expect-ts-use trx 0 0 states * TCH/F TCH/F TCH/F TCH/F TCH/F - *
+expect-ts-use trx 0 0 states * TCH/F - TCH/F TCH/F TCH/F TCH/F *
# Also test for TCH/H
create-bts trx-count 1 timeslots c+s4 TCH/H TCH/H TCH/H TCH/H TCH/H TCH/H PDCH
@@ -54,23 +49,19 @@ network
res-ind trx 1 0 levels - 54 32 21 23 45 54 -
create-ms bts 1 TCH/H AMR
-# FAIL: interference is ignored
-expect-ts-use trx 1 0 states * TCH/H- - - - - - *
+expect-ts-use trx 1 0 states * - - TCH/-H - - - *
# Favor lchans that have an indicated interference level
res-ind trx 1 0 levels - - - 4- 3- - - -
create-ms bts 1 TCH/H AMR
-# FAIL: interference is ignored
-expect-ts-use trx 1 0 states * TCH/HH - - - - - *
+expect-ts-use trx 1 0 states * - - TCH/-H TCH/H- - - *
# For equal levels, pick the first
res-ind trx 1 0 levels - -2 22 2- -2 22 2- -
create-ms bts 1 TCH/H AMR
-# FAIL: interference is ignored
-expect-ts-use trx 1 0 states * TCH/HH TCH/H- - - - - *
+expect-ts-use trx 1 0 states * TCH/-H - TCH/-H TCH/H- - - *
# Test clamping of indexes > 5
res-ind trx 1 0 levels - 7- 67 6- -7 54 6- -
create-ms bts 1 TCH/H AMR
-# FAIL: interference is ignored
-expect-ts-use trx 1 0 states * TCH/HH TCH/HH - - - - *
+expect-ts-use trx 1 0 states * TCH/-H - TCH/-H TCH/H- TCH/-H - *