diff options
Diffstat (limited to 'src/common')
| -rw-r--r-- | src/common/Makefile.am | 2 | ||||
| -rw-r--r-- | src/common/measurement.c | 6 | ||||
| -rw-r--r-- | src/common/ta_control.c | 55 |
3 files changed, 62 insertions, 1 deletions
diff --git a/src/common/Makefile.am b/src/common/Makefile.am index 113ff2f4..0a10abf7 100644 --- a/src/common/Makefile.am +++ b/src/common/Makefile.am @@ -12,6 +12,6 @@ libbts_a_SOURCES = gsm_data_shared.c sysinfo.c logging.c abis.c oml.c bts.c \ load_indication.c pcu_sock.c handover.c msg_utils.c \ tx_power.c bts_ctrl_commands.c bts_ctrl_lookup.c \ l1sap.c cbch.c power_control.c main.c phy_link.c \ - dtx_dl_amr_fsm.c scheduler_mframe.c + dtx_dl_amr_fsm.c scheduler_mframe.c ta_control.c libl1sched_a_SOURCES = scheduler.c diff --git a/src/common/measurement.c b/src/common/measurement.c index 3e0daf19..ddc17474 100644 --- a/src/common/measurement.c +++ b/src/common/measurement.c @@ -10,6 +10,7 @@ #include <osmo-bts/measurement.h> #include <osmo-bts/scheduler.h> #include <osmo-bts/rsl.h> +#include <osmo-bts/ta_control.h> /* Tables as per TS 45.008 Section 8.3 */ static const uint8_t ts45008_83_tch_f[] = { 52, 53, 54, 55, 56, 57, 58, 59 }; @@ -696,6 +697,11 @@ int lchan_meas_check_compute(struct gsm_lchan *lchan, uint32_t fn) lchan_meas_compute_extended(lchan); + /* Compute new ta_req value. This has to be done here since the value + * in lchan->meas.num_ul_meas together with lchan->meas.ms_toa256 + * is needed for the computation. */ + lchan_ms_ta_ctrl(lchan); + lchan->meas.num_ul_meas = 0; /* return 1 to indicate that the computation has been done and the next diff --git a/src/common/ta_control.c b/src/common/ta_control.c new file mode 100644 index 00000000..2ccc41a8 --- /dev/null +++ b/src/common/ta_control.c @@ -0,0 +1,55 @@ +/* Loop control for Timing Advance */ + +/* (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 <osmo-bts/gsm_data.h> +#include <osmo-bts/logging.h> + +/* 90% of one bit duration in 1/256 symbols: 256*0.9 */ +#define TOA256_9OPERCENT 230 + +/* rqd_ta value range */ +#define TOA_MIN 0 +#define TOA_MAX 63 + +void lchan_ms_ta_ctrl(struct gsm_lchan *lchan) +{ + int16_t toa256 = lchan->meas.ms_toa256; + + /* Do not perform any computation when the amount of measurement + * results is too little. */ + if (lchan->meas.num_ul_meas < 4) + return; + + if (toa256 < -TOA256_9OPERCENT && lchan->rqd_ta > TOA_MIN) { + LOGPLCHAN(lchan, DLOOP, LOGL_INFO, + "TOA is too early (%d), now lowering TA from %d to %d\n", + toa256, lchan->rqd_ta, lchan->rqd_ta - 1); + lchan->rqd_ta--; + } else if (toa256 > TOA256_9OPERCENT && lchan->rqd_ta < TOA_MAX) { + LOGPLCHAN(lchan, DLOOP, LOGL_INFO, + "TOA is too late (%d), now raising TA from %d to %d\n", + toa256, lchan->rqd_ta, lchan->rqd_ta + 1); + lchan->rqd_ta++; + } else + LOGPLCHAN(lchan, DLOOP, LOGL_DEBUG, + "TOA is correct (%d), keeping current TA of %d\n", + toa256, lchan->rqd_ta); +} |