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/* MS Power Control Loop L1 */
/* (C) 2014 by Holger Hans Peter Freyther
*
* 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 <errno.h>
#include <inttypes.h>
#include <osmo-bts/logging.h>
#include <osmo-bts/bts.h>
#include <osmo-bts/gsm_data.h>
#include <osmo-bts/measurement.h>
#include <osmo-bts/bts_model.h>
#include <osmo-bts/l1sap.h>
/*! compute the new MS POWER LEVEL communicated to the MS and store it in lchan.
* \param lchan logical channel for which to compute (and in which to store) new power value.
* \param[in] ms_power MS Power Level received from Uplink L1 SACCH Header in SACCH block.
* \param[in] rxLevel Signal level of the received SACCH block, in dBm.
*/
int lchan_ms_pwr_ctrl(struct gsm_lchan *lchan,
const uint8_t ms_power, const int rxLevel)
{
int diff;
struct gsm_bts_trx *trx = lchan->ts->trx;
struct gsm_bts *bts = trx->bts;
enum gsm_band band = bts->band;
int8_t new_power; /* TS 05.05 power level */
int8_t new_dbm, current_dbm, bsc_max_dbm;
if (!trx_ms_pwr_ctrl_is_osmo(lchan->ts->trx))
return 0;
if (lchan->ms_power_ctrl.fixed)
return 0;
/* The phone hasn't reached the power level yet.
TODO: store .last and check if MS is trying to move towards current. */
if (lchan->ms_power_ctrl.current != ms_power) {
if (lchan->ms_power_ctrl.last_received == -1 ||
lchan->ms_power_ctrl.last_received != ms_power) {
/* MS Power still changing, keep current power level */
lchan->ms_power_ctrl.last_received = ms_power;
return 0;
}
/* else: we are stuck with some received MS Power level
different than the one we announce, probably because the MS
doesn't support that exact one so it picked the nearest one
*/
lchan->ms_power_ctrl.last_received = ms_power;
}
/* How many dBs measured power should be increased (+) or decreased (-)
to reach expected power. */
diff = bts->ul_power_target - rxLevel;
/* power levels change in steps of 2 dB, so a smaller diff will end up in no change */
if (diff < 2 && diff > -2)
return 0;
current_dbm = ms_pwr_dbm(band, lchan->ms_power_ctrl.current);
if (current_dbm < 0) {
LOGPLCHAN(lchan, DLOOP, LOGL_NOTICE,
"Failed to calculate dBm for power ctl level %" PRIu8 " on band %s\n",
lchan->ms_power_ctrl.current, gsm_band_name(band));
return 0;
}
bsc_max_dbm = ms_pwr_dbm(band, lchan->ms_power_ctrl.max);
if (bsc_max_dbm < 0) {
LOGPLCHAN(lchan, DLOOP, LOGL_NOTICE,
"Failed to calculate dBm for power ctl level %" PRIu8 " on band %s\n",
lchan->ms_power_ctrl.max, gsm_band_name(band));
return 0;
}
new_dbm = current_dbm + diff;
/* Make sure new_dbm is never negative. ms_pwr_ctl_lvl() can later on
cope with any unsigned dbm value, regardless of band minimal value. */
if (new_dbm < 0)
new_dbm = 0;
/* Don't ask for smaller ms power level than the one set by BSC upon RSL CHAN ACT */
if (new_dbm > bsc_max_dbm)
new_dbm = bsc_max_dbm;
new_power = ms_pwr_ctl_lvl(band, new_dbm);
if (new_power < 0) {
LOGPLCHAN(lchan, DLOOP, LOGL_NOTICE,
"Failed to retrieve power level for %" PRId8 " dBm on band %d\n",
new_dbm, band);
return 0;
}
if (lchan->ms_power_ctrl.current == new_power) {
LOGPLCHAN(lchan, DLOOP, LOGL_INFO, "Keeping MS new_power at control level %d, %d dBm "
"(rx-ms-pwr-lvl %" PRIu8 ", rx-current %d dBm, rx-target %d dBm)\n",
new_power, ms_pwr_dbm(band, new_power), ms_power, rxLevel, bts->ul_power_target);
return 0;
}
LOGPLCHAN(lchan, DLOOP, LOGL_INFO, "%s MS new_power from control level %d (%d dBm) to %d, %d dBm "
"(rx-ms-pwr-lvl %" PRIu8 ", rx-current %d dBm, rx-target %d dBm)\n",
(diff > 0) ? "Raising" : "Lowering",
lchan->ms_power_ctrl.current, ms_pwr_dbm(band, lchan->ms_power_ctrl.current),
new_power, ms_pwr_dbm(band, new_power), ms_power, rxLevel, bts->ul_power_target);
/* store the resulting new MS power level in the lchan */
lchan->ms_power_ctrl.current = new_power;
bts_model_adjst_ms_pwr(lchan);
return 1;
}
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