117 lines
3.1 KiB
C
117 lines
3.1 KiB
C
/* AMR link adaptation loop (see 3GPP TS 45.009, section 3) */
|
|
|
|
/* (C) 2013 by Andreas Eversberg <jolly@eversberg.eu>
|
|
*
|
|
* All Rights Reserved
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU Affero General Public License as published by
|
|
* the Free Software Foundation; either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Affero General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
*/
|
|
|
|
#include <stdint.h>
|
|
#include <unistd.h>
|
|
#include <stdlib.h>
|
|
#include <errno.h>
|
|
#include <inttypes.h>
|
|
|
|
#include <osmo-bts/gsm_data.h>
|
|
#include <osmo-bts/logging.h>
|
|
#include <osmocom/gsm/gsm_utils.h>
|
|
|
|
#include "amr_loop.h"
|
|
|
|
void trx_loop_amr_input(struct l1sched_chan_state *chan_state,
|
|
int n_errors, int n_bits_total)
|
|
{
|
|
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;
|
|
|
|
/* check if loop is enabled */
|
|
if (!chan_state->amr_loop)
|
|
return;
|
|
|
|
/* wait for MS to use the requested codec */
|
|
if (chan_state->ul_ft != chan_state->dl_cmr)
|
|
return;
|
|
|
|
/* count bit errors */
|
|
if (lchan->type == GSM_LCHAN_TCH_H) {
|
|
chan_state->ber_num += 2;
|
|
chan_state->ber_sum += (ber + ber);
|
|
} else {
|
|
chan_state->ber_num++;
|
|
chan_state->ber_sum += ber;
|
|
}
|
|
|
|
/* count frames */
|
|
if (chan_state->ber_num < 48)
|
|
return;
|
|
|
|
/* calculate average (reuse ber variable) */
|
|
ber = chan_state->ber_sum / chan_state->ber_num;
|
|
|
|
/* reset bit errors */
|
|
chan_state->ber_num = 0;
|
|
chan_state->ber_sum = 0;
|
|
|
|
LOGPLCHAN(lchan, DLOOP, LOGL_DEBUG, "Current bit error rate (BER) %.6f "
|
|
"codec id %d\n", ber, chan_state->ul_ft);
|
|
|
|
/* 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);
|
|
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);
|
|
chan_state->dl_cmr++;
|
|
}
|
|
}
|
|
}
|
|
|
|
void trx_loop_amr_set(struct l1sched_chan_state *chan_state, int loop)
|
|
{
|
|
if (chan_state->amr_loop && !loop) {
|
|
chan_state->amr_loop = 0;
|
|
return;
|
|
}
|
|
|
|
if (!chan_state->amr_loop && loop) {
|
|
chan_state->amr_loop = 1;
|
|
|
|
/* reset bit errors */
|
|
chan_state->ber_num = 0;
|
|
chan_state->ber_sum = 0;
|
|
|
|
return;
|
|
}
|
|
}
|