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laforge gerrit-no-reply at lists.osmocom.orglaforge has submitted this change. ( https://gerrit.osmocom.org/c/osmo-bts/+/24613 )
Change subject: osmo-bts-trx: report interference levels to the upper layers
......................................................................
osmo-bts-trx: report interference levels to the upper layers
In trx_sched_ul_burst(), treat all BURST.ind and NOPE.ind mapped
to inactive logical channels as interference. Average the RSSI
values on the fly using a sliding average with constant a=0.5.
Report averaged values for each logical channel every 104 TDMA
frames (SACCH period) by calling gsm_lchan_interf_meas_push().
Change-Id: I4686448e42a40df56c1d27a14fd0a4d43fd144a5
Related: I78b6d8beffa5228a28231b75728e7aebdd3cb23c
Related: SYS#5313, OS#1569
---
M include/osmo-bts/scheduler.h
M src/common/scheduler.c
M src/osmo-bts-trx/scheduler_trx.c
3 files changed, 100 insertions(+), 10 deletions(-)
Approvals:
Jenkins Builder: Verified
dexter: Looks good to me, approved
pespin: Looks good to me, but someone else must approve
laforge: Looks good to me, but someone else must approve
diff --git a/include/osmo-bts/scheduler.h b/include/osmo-bts/scheduler.h
index 40b7330..80a260f 100644
--- a/include/osmo-bts/scheduler.h
+++ b/include/osmo-bts/scheduler.h
@@ -136,10 +136,14 @@
uint8_t ul_encr_key[MAX_A5_KEY_LEN];
uint8_t dl_encr_key[MAX_A5_KEY_LEN];
- /* Simple ring buffer (up to 8 unique measurements) */
+ /* Uplink measurements */
struct {
- struct l1sched_meas_set buf[8];
+ /* Active channel measurements (simple ring buffer) */
+ struct l1sched_meas_set buf[8]; /* up to 8 entries */
unsigned int current; /* current position */
+
+ /* Interference measurements */
+ int interf_avg; /* sliding average */
} meas;
/* handover */
diff --git a/src/common/scheduler.c b/src/common/scheduler.c
index 0e1f495..a010b39 100644
--- a/src/common/scheduler.c
+++ b/src/common/scheduler.c
@@ -1444,6 +1444,31 @@
return 0;
}
+/* Process a single noise measurement for an inactive timeslot. */
+static void trx_sched_noise_meas(struct l1sched_chan_state *l1cs,
+ const struct trx_ul_burst_ind *bi)
+{
+ int *Avg = &l1cs->meas.interf_avg;
+
+ /* EWMA (Exponentially Weighted Moving Average):
+ *
+ * Avg[n] = a * Val[n] + (1 - a) * Avg[n - 1]
+ *
+ * Implemented using the '+=' operator:
+ *
+ * Avg += a * Val - a * Avg
+ * Avg += a * (Val - Avg)
+ *
+ * We use constant 'a' = 0.5, what is equal to:
+ *
+ * Avg += (Val - Avg) / 2
+ *
+ * We don't really need precisity here, so no scaling.
+ */
+
+ *Avg += (bi->rssi - *Avg) / 2;
+}
+
/* Process an Uplink burst indication */
int trx_sched_ul_burst(struct l1sched_ts *l1ts, struct trx_ul_burst_ind *bi)
{
@@ -1469,15 +1494,13 @@
l1cs = &l1ts->chan_state[bi->chan];
func = trx_chan_desc[bi->chan].ul_fn;
- /* TODO: handle noise measurements */
- if (bi->chan == TRXC_IDLE && bi->flags & TRX_BI_F_NOPE_IND) {
- LOGL1SB(DL1P, LOGL_DEBUG, l1ts, bi, "Rx noise measurement (%d)\n", bi->rssi);
- return -ENOTSUP;
- }
-
/* check if channel is active */
- if (!TRX_CHAN_IS_ACTIVE(l1cs, bi->chan))
- return -EINVAL;
+ if (!TRX_CHAN_IS_ACTIVE(l1cs, bi->chan)) {
+ /* handle noise measurements */
+ if (TRX_CHAN_IS_DEDIC(bi->chan))
+ trx_sched_noise_meas(l1cs, bi);
+ return 0;
+ }
/* omit bursts which have no handler, like IDLE bursts */
if (!func)
diff --git a/src/osmo-bts-trx/scheduler_trx.c b/src/osmo-bts-trx/scheduler_trx.c
index 1a4f03f..0a2052c 100644
--- a/src/osmo-bts-trx/scheduler_trx.c
+++ b/src/osmo-bts-trx/scheduler_trx.c
@@ -60,6 +60,65 @@
return 0;
}
+static void ts_report_interf_meas(const struct gsm_bts_trx_ts *ts)
+{
+ const struct l1sched_ts *l1ts = ts->priv;
+ unsigned int ln;
+
+ for (ln = 0; ln < ARRAY_SIZE(ts->lchan); ln++) {
+ const struct gsm_lchan *lchan = &ts->lchan[ln];
+ enum trx_chan_type dcch, acch;
+ int interf_avg;
+
+ /* We're not interested in active channels */
+ if (lchan->state == LCHAN_S_ACTIVE)
+ continue;
+
+ switch (lchan->type) {
+ case GSM_LCHAN_SDCCH:
+ if (ts->pchan == GSM_PCHAN_CCCH_SDCCH4 ||
+ ts->pchan == GSM_PCHAN_CCCH_SDCCH4_CBCH) {
+ dcch = TRXC_SDCCH4_0 + ln;
+ acch = TRXC_SACCH4_0 + ln;
+ } else { /* SDCCH/8 otherwise */
+ dcch = TRXC_SDCCH8_0 + ln;
+ acch = TRXC_SACCH8_0 + ln;
+ }
+ break;
+ case GSM_LCHAN_TCH_F:
+ dcch = TRXC_TCHF;
+ acch = TRXC_SACCHTF;
+ break;
+ case GSM_LCHAN_TCH_H:
+ dcch = TRXC_TCHH_0 + ln;
+ acch = TRXC_SACCHTH_0 + ln;
+ break;
+ default:
+ /* Skip other lchan types */
+ continue;
+ }
+
+ OSMO_ASSERT(dcch < ARRAY_SIZE(l1ts->chan_state));
+ OSMO_ASSERT(acch < ARRAY_SIZE(l1ts->chan_state));
+
+ interf_avg = (l1ts->chan_state[dcch].meas.interf_avg +
+ l1ts->chan_state[acch].meas.interf_avg) / 2;
+
+ gsm_lchan_interf_meas_push((struct gsm_lchan *) lchan, interf_avg);
+ }
+}
+
+static void bts_report_interf_meas(const struct gsm_bts *bts)
+{
+ const struct gsm_bts_trx *trx;
+ unsigned int tn;
+
+ llist_for_each_entry(trx, &bts->trx_list, list) {
+ for (tn = 0; tn < ARRAY_SIZE(trx->ts); tn++)
+ ts_report_interf_meas(&trx->ts[tn]);
+ }
+}
+
/* Find a route (PHY instance) for a given Downlink burst request */
static struct phy_instance *dlfh_route_br(const struct trx_dl_burst_req *br,
struct gsm_bts_trx_ts *ts)
@@ -189,6 +248,10 @@
struct gsm_bts_trx *trx;
unsigned int tn;
+ /* Report interference measurements */
+ if (fn % 104 == 0) /* SACCH period */
+ bts_report_interf_meas(bts);
+
/* send time indication */
l1if_mph_time_ind(bts, fn);
--
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Gerrit-Project: osmo-bts
Gerrit-Branch: master
Gerrit-Change-Id: I4686448e42a40df56c1d27a14fd0a4d43fd144a5
Gerrit-Change-Number: 24613
Gerrit-PatchSet: 5
Gerrit-Owner: fixeria <vyanitskiy at sysmocom.de>
Gerrit-Reviewer: Hoernchen <ewild at sysmocom.de>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: dexter <pmaier at sysmocom.de>
Gerrit-Reviewer: laforge <laforge at osmocom.org>
Gerrit-Reviewer: pespin <pespin at sysmocom.de>
Gerrit-CC: neels <nhofmeyr at sysmocom.de>
Gerrit-MessageType: merged
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