fixeria has submitted this change. (
https://gerrit.osmocom.org/c/osmo-bts/+/27758 )
Change subject: osmo-bts-trx: use C/I in the AMR link adaptation loop
......................................................................
osmo-bts-trx: use C/I in the AMR link adaptation loop
Change-Id: Ide84bf864f56020c0265cfb9731615d4f7bad7f5
Related: SYS#5917, OS#4984
---
M include/osmo-bts/scheduler.h
M src/common/scheduler.c
M src/osmo-bts-trx/amr_loop.c
M src/osmo-bts-trx/amr_loop.h
M src/osmo-bts-trx/sched_lchan_tchf.c
M src/osmo-bts-trx/sched_lchan_tchh.c
6 files changed, 53 insertions(+), 49 deletions(-)
Approvals:
laforge: Looks good to me, but someone else must approve
fixeria: Looks good to me, approved
osmith: Looks good to me, but someone else must approve
Jenkins Builder: Verified
diff --git a/include/osmo-bts/scheduler.h b/include/osmo-bts/scheduler.h
index e39315f..eab904c 100644
--- a/include/osmo-bts/scheduler.h
+++ b/include/osmo-bts/scheduler.h
@@ -114,8 +114,8 @@
/* AMR */
uint8_t codec[4]; /* 4 possible codecs for amr */
int codecs; /* number of possible codecs */
- float ber_sum; /* sum of bit error rates */
- int ber_num; /* number of bit error rates */
+ int lqual_cb_sum; /* sum of link quality samples
(in cB) */
+ int lqual_cb_num; /* number of link quality
samples */
uint8_t ul_ft; /* current uplink FT index */
uint8_t dl_ft; /* current downlink FT index */
uint8_t ul_cmr; /* current uplink CMR index */
diff --git a/src/common/scheduler.c b/src/common/scheduler.c
index 96189ef..8ec9ccf 100644
--- a/src/common/scheduler.c
+++ b/src/common/scheduler.c
@@ -1185,8 +1185,8 @@
chan_state->dl_ft = initial_id;
chan_state->ul_cmr = initial_id;
chan_state->dl_cmr = initial_id;
- chan_state->ber_sum = 0;
- chan_state->ber_num = 0;
+ chan_state->lqual_cb_sum = 0;
+ chan_state->lqual_cb_num = 0;
}
rc = 0;
}
diff --git a/src/osmo-bts-trx/amr_loop.c b/src/osmo-bts-trx/amr_loop.c
index e5c7fec..5793d03 100644
--- a/src/osmo-bts-trx/amr_loop.c
+++ b/src/osmo-bts-trx/amr_loop.c
@@ -1,6 +1,7 @@
/* AMR link adaptation loop (see 3GPP TS 45.009, section 3) */
/* (C) 2013 by Andreas Eversberg <[email protected]>
+ * (C) 2022 by sysmocom - s.m.f.c. GmbH <[email protected]>
*
* All Rights Reserved
*
@@ -32,16 +33,11 @@
#include "amr_loop.h"
void trx_loop_amr_input(struct l1sched_chan_state *chan_state,
- int n_errors, int n_bits_total)
+ const struct l1sched_meas_set *meas_set)
{
- struct gsm_lchan *lchan = chan_state->lchan;
- float ber;
-
- /* calculate BER (Bit Error Ratio) */
- if (n_bits_total == 0)
- ber = 1.0; /* 100% BER */
- else
- ber = (float) n_errors / (float) n_bits_total;
+ const struct gsm_lchan *lchan = chan_state->lchan;
+ const struct amr_multirate_conf *cfg = &lchan->tch.amr_mr;
+ int lqual_cb = meas_set->ci_cb; /* cB (centibel) */
/* check if loop is enabled */
if (!chan_state->amr_loop)
@@ -51,47 +47,54 @@
if (chan_state->ul_ft != chan_state->dl_cmr)
return;
- /* count bit errors */
+ /* count per-block C/I samples for further averaging */
if (lchan->type == GSM_LCHAN_TCH_H) {
- chan_state->ber_num += 2;
- chan_state->ber_sum += (ber + ber);
+ chan_state->lqual_cb_num += 2;
+ chan_state->lqual_cb_sum += (lqual_cb + lqual_cb);
} else {
- chan_state->ber_num++;
- chan_state->ber_sum += ber;
+ chan_state->lqual_cb_num++;
+ chan_state->lqual_cb_sum += lqual_cb;
}
/* count frames */
- if (chan_state->ber_num < 48)
+ if (chan_state->lqual_cb_num < 48)
return;
- /* calculate average (reuse ber variable) */
- ber = chan_state->ber_sum / chan_state->ber_num;
+ /* calculate average (reuse lqual_cb variable) */
+ lqual_cb = chan_state->lqual_cb_sum / chan_state->lqual_cb_num;
- /* reset bit errors */
- chan_state->ber_num = 0;
- chan_state->ber_sum = 0;
+ LOGPLCHAN(lchan, DLOOP, LOGL_DEBUG, "AMR link quality (C/I) is %d cB, "
+ "codec mode=%d\n", lqual_cb, chan_state->ul_ft);
- LOGPLCHAN(lchan, DLOOP, LOGL_DEBUG, "Current bit error rate (BER) %.6f "
- "codec id %d\n", ber, chan_state->ul_ft);
+ /* reset the link quality measurements */
+ chan_state->lqual_cb_num = 0;
+ chan_state->lqual_cb_sum = 0;
- /* degrade */
if (chan_state->dl_cmr > 0) {
- /* degrade, if ber is above threshold FIXME: C/I */
- if (ber >
- lchan->tch.amr_mr.mode[chan_state->dl_cmr-1].threshold) {
- LOGPLCHAN(lchan, DLOOP, LOGL_DEBUG, "Degrading due to
BER %.6f "
- "from codec id %d to %d\n", ber,
chan_state->dl_cmr,
- chan_state->dl_cmr - 1);
+ /* The threshold/hysteresis is in 0.5 dB steps, convert to cB:
+ * 1dB is 10cB, so 0.5dB is 5cB - this is why we multiply by 5.
*/
+ const int thresh_lower_cb = cfg->mode[chan_state->dl_cmr -
1].threshold * 5;
+
+ /* Degrade if the link quality is below THR_MX_Dn(i - 1) */
+ if (lqual_cb < thresh_lower_cb) {
+ LOGPLCHAN(lchan, DLOOP, LOGL_INFO, "Degrading AMR codec
mode: "
+ "%d -> %d due to link quality %d cB <
THR_MX_Dn=%d cB\n",
+ chan_state->dl_cmr, chan_state->dl_cmr - 1,
+ lqual_cb, thresh_lower_cb);
chan_state->dl_cmr--;
}
} else if (chan_state->dl_cmr < chan_state->codecs - 1) {
- /* degrade, if ber is above threshold FIXME: C/I*/
- if (ber <
- lchan->tch.amr_mr.mode[chan_state->dl_cmr].threshold
- - lchan->tch.amr_mr.mode[chan_state->dl_cmr].hysteresis) {
- LOGPLCHAN(lchan, DLOOP, LOGL_DEBUG, "Upgrading due to
BER %.6f "
- "from codec id %d to %d\n", ber,
chan_state->dl_cmr,
- chan_state->dl_cmr + 1);
+ /* The threshold/hysteresis is in 0.5 dB steps, convert to cB:
+ * 1dB is 10cB, so 0.5dB is 5cB - this is why we multiply by 5.
*/
+ const int thresh_upper_cb =
cfg->mode[chan_state->dl_cmr].threshold * 5 \
+ +
cfg->mode[chan_state->dl_cmr].hysteresis * 5;
+
+ /* Upgrade if the link quality is above THR_MX_Up(i) */
+ if (lqual_cb > thresh_upper_cb) {
+ LOGPLCHAN(lchan, DLOOP, LOGL_INFO, "Upgrading AMR codec
mode: "
+ "%d -> %d due to link quality %d cB >
THR_MX_Up=%d cB\n",
+ chan_state->dl_cmr, chan_state->dl_cmr + 1,
+ lqual_cb, thresh_upper_cb);
chan_state->dl_cmr++;
}
}
@@ -102,9 +105,9 @@
if (chan_state->amr_loop == loop)
return;
if (!chan_state->amr_loop) {
- /* reset bit errors */
- chan_state->ber_num = 0;
- chan_state->ber_sum = 0;
+ /* reset the link quality measurements */
+ chan_state->lqual_cb_num = 0;
+ chan_state->lqual_cb_sum = 0;
}
chan_state->amr_loop = loop;
diff --git a/src/osmo-bts-trx/amr_loop.h b/src/osmo-bts-trx/amr_loop.h
index 85f73fd..efff76c 100644
--- a/src/osmo-bts-trx/amr_loop.h
+++ b/src/osmo-bts-trx/amr_loop.h
@@ -11,6 +11,6 @@
*/
void trx_loop_amr_input(struct l1sched_chan_state *chan_state,
- int n_errors, int n_bits_total);
+ const struct l1sched_meas_set *meas_set);
void trx_loop_amr_set(struct l1sched_chan_state *chan_state, int loop);
diff --git a/src/osmo-bts-trx/sched_lchan_tchf.c
b/src/osmo-bts-trx/sched_lchan_tchf.c
index 8ca0961..fb19dd2 100644
--- a/src/osmo-bts-trx/sched_lchan_tchf.c
+++ b/src/osmo-bts-trx/sched_lchan_tchf.c
@@ -197,8 +197,6 @@
break;
}
- if (rc)
- trx_loop_amr_input(chan_state, n_errors, n_bits_total);
/* only good speech frames get rtp header */
if (rc != GSM_MACBLOCK_LEN && rc >= 4) {
if (chan_state->amr_last_dtx == AMR_OTHER) {
@@ -225,6 +223,9 @@
/* meas_avg.fn now contains TDMA frame number of the first burst */
fn_begin = meas_avg.fn;
+ if (tch_mode == GSM48_CMODE_SPEECH_AMR)
+ trx_loop_amr_input(chan_state, &meas_avg);
+
/* Check if the frame is bad */
if (rc < 0) {
LOGL1SB(DL1P, LOGL_NOTICE, l1ts, bi, "Received bad data
(%u/%u)\n",
diff --git a/src/osmo-bts-trx/sched_lchan_tchh.c
b/src/osmo-bts-trx/sched_lchan_tchh.c
index e3ce600..1b4aa40 100644
--- a/src/osmo-bts-trx/sched_lchan_tchh.c
+++ b/src/osmo-bts-trx/sched_lchan_tchh.c
@@ -233,9 +233,6 @@
break;
}
- if (rc)
- trx_loop_amr_input(chan_state, n_errors, n_bits_total);
-
/* only good speech frames get rtp header */
if (rc != GSM_MACBLOCK_LEN && rc >= 4) {
if (chan_state->amr_last_dtx == AMR_OTHER) {
@@ -264,6 +261,9 @@
/* meas_avg.fn now contains TDMA frame number of the first burst */
fn_begin = meas_avg.fn;
+ if (tch_mode == GSM48_CMODE_SPEECH_AMR)
+ trx_loop_amr_input(chan_state, &meas_avg);
+
/* Check if the frame is bad */
if (rc < 0) {
LOGL1SB(DL1P, LOGL_NOTICE, l1ts, bi, "Received bad data
(%u/%u)\n",
--
To view, visit https://gerrit.osmocom.org/c/osmo-bts/+/27758
To unsubscribe, or for help writing mail filters, visit
https://gerrit.osmocom.org/settings
Gerrit-Project: osmo-bts
Gerrit-Branch: master
Gerrit-Change-Id: Ide84bf864f56020c0265cfb9731615d4f7bad7f5
Gerrit-Change-Number: 27758
Gerrit-PatchSet: 6
Gerrit-Owner: fixeria <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: dexter <[email protected]>
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: osmith <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>
Gerrit-MessageType: merged
