118 lines
3.9 KiB
C
118 lines
3.9 KiB
C
/* MS Power Control Loop L1 */
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/* (C) 2014 by Holger Hans Peter Freyther
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <stdint.h>
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#include <unistd.h>
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#include <errno.h>
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#include <inttypes.h>
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#include <osmo-bts/logging.h>
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#include <osmo-bts/bts.h>
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#include <osmo-bts/gsm_data.h>
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#include <osmo-bts/measurement.h>
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#include <osmo-bts/bts_model.h>
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#include <osmo-bts/l1sap.h>
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/*! compute the new MS POWER LEVEL communicated to the MS and store it in lchan.
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* \param lchan logical channel for which to compute (and in which to store) new power value.
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* \param[in] ms_power MS Power Level received from Uplink L1 SACCH Header in SACCH block.
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* \param[in] rxLevel Signal level of the received SACCH block, in dBm.
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*/
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int lchan_ms_pwr_ctrl(struct gsm_lchan *lchan,
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const uint8_t ms_power, const int rxLevel)
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{
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int diff;
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struct gsm_bts_trx *trx = lchan->ts->trx;
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struct gsm_bts *bts = trx->bts;
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enum gsm_band band = bts->band;
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int8_t new_power; /* TS 05.05 power level */
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int8_t new_dbm, current_dbm, bsc_max_dbm;
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if (!trx_ms_pwr_ctrl_is_osmo(lchan->ts->trx))
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return 0;
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if (lchan->ms_power_ctrl.fixed)
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return 0;
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/* The phone hasn't reached the power level yet.
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TODO: store .last and check if MS is trying to move towards current. */
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if (lchan->ms_power_ctrl.current != ms_power)
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return 0;
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/* How many dBs measured power should be increased (+) or decreased (-)
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to reach expected power. */
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diff = bts->ul_power_target - rxLevel;
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/* power levels change in steps of 2 dB, so a smaller diff will end up in no change */
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if (diff < 2 && diff > -2)
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return 0;
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current_dbm = ms_pwr_dbm(band, lchan->ms_power_ctrl.current);
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if (current_dbm < 0) {
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LOGPLCHAN(lchan, DLOOP, LOGL_NOTICE,
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"Failed to calculate dBm for power ctl level %" PRIu8 " on band %s\n",
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lchan->ms_power_ctrl.current, gsm_band_name(band));
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return 0;
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}
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bsc_max_dbm = ms_pwr_dbm(band, lchan->ms_power_ctrl.max);
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if (bsc_max_dbm < 0) {
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LOGPLCHAN(lchan, DLOOP, LOGL_NOTICE,
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"Failed to calculate dBm for power ctl level %" PRIu8 " on band %s\n",
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lchan->ms_power_ctrl.max, gsm_band_name(band));
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return 0;
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}
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new_dbm = current_dbm + diff;
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/* Make sure new_dbm is never negative. ms_pwr_ctl_lvl() can later on
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cope with any unsigned dbm value, regardless of band minimal value. */
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if (new_dbm < 0)
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new_dbm = 0;
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/* Don't ask for smaller ms power level than the one set by BSC upon RSL CHAN ACT */
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if (new_dbm > bsc_max_dbm)
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new_dbm = bsc_max_dbm;
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new_power = ms_pwr_ctl_lvl(band, new_dbm);
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if (new_power < 0) {
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LOGPLCHAN(lchan, DLOOP, LOGL_NOTICE,
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"Failed to retrieve power level for %" PRId8 " dBm on band %d\n",
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new_dbm, band);
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return 0;
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}
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if (lchan->ms_power_ctrl.current == new_power) {
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LOGPLCHAN(lchan, DLOOP, LOGL_INFO, "Keeping MS new_power at control level %d (%d dBm)\n",
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new_power, ms_pwr_dbm(band, new_power));
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return 0;
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}
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LOGPLCHAN(lchan, DLOOP, LOGL_INFO, "%s MS new_power from control level %d (%d dBm) to %d (%d dBm)\n",
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(diff > 0) ? "Raising" : "Lowering",
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lchan->ms_power_ctrl.current, ms_pwr_dbm(band, lchan->ms_power_ctrl.current),
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new_power, ms_pwr_dbm(band, new_power));
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/* store the resulting new MS power level in the lchan */
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lchan->ms_power_ctrl.current = new_power;
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bts_model_adjst_ms_pwr(lchan);
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return 1;
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}
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