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

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
This commit is contained in:
Neels Hofmeyr 2021-07-08 04:20:59 +02:00
parent f764248b03
commit 5ac7075643
2 changed files with 57 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
src/osmo-bsc/lchan_select.c
View File

@ -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
}

27
tests/handover/test_resource_indication.ho_vty
View File

@ -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 - *