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/* Loop control for OsmoBTS-TRX */
/* (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 <osmo-bts/l1sap.h>
#include <osmocom/core/bits.h>
#include <osmocom/gsm/gsm_utils.h>
#include "trx_if.h"
#include "l1_if.h"
#include "loops.h"
void trx_loop_amr_input(struct l1sched_trx *l1t, uint8_t chan_nr,
struct l1sched_chan_state *chan_state,
int n_errors, int n_bits_total)
{
struct gsm_bts_trx *trx = l1t->trx;
struct gsm_lchan *lchan = &trx->ts[L1SAP_CHAN2TS(chan_nr)]
.lchan[l1sap_chan2ss(chan_nr)];
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 (L1SAP_IS_CHAN_TCHH(chan_nr)) {
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.bts_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.bts_mode[chan_state->dl_cmr].threshold
- lchan->tch.amr_mr.bts_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;
}
}
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