diff options
| author | Pau Espin Pedrol <pespin@sysmocom.de> | 2019-11-20 19:02:25 +0100 |
|---|---|---|
| committer | Pau Espin Pedrol <pespin@sysmocom.de> | 2019-11-20 20:27:04 +0100 |
| commit | 1d9f6efccb2dfed52069910901ec8c8cc0d8de46 (patch) | |
| tree | 458f1fc6df484dfe2470c33842f36215e885b09f /src/common | |
| parent | 522fc939e079c1dfd9b395548c75b52b92fc8adf (diff) | |
power_control.c: Limit speed of announced MS Power Level value changes
It's not a good idea to request big changes in MS Power based on
sporadic bad signal received, let's instead change announced MS power
levels more smoothly to avoid possible big signal strength fluctations,
similar to what is already done in osmo-bts-trx specific loop (loops.c).
Related: OS#1851
Change-Id: Iecc4ec7e21471ec853ad2d5659af4052aba5444c
Diffstat (limited to 'src/common')
| -rw-r--r-- | src/common/power_control.c | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/src/common/power_control.c b/src/common/power_control.c index d08ed5e5..d2a6c1dd 100644 --- a/src/common/power_control.c +++ b/src/common/power_control.c @@ -30,6 +30,11 @@ #include <osmo-bts/measurement.h> #include <osmo-bts/bts_model.h> #include <osmo-bts/l1sap.h> +#include <osmo-bts/power_control.h> + +/* how many dB do we raise/lower as maximum (1 ms power level = 2 dB) */ +#define MS_RAISE_MAX_DB 4 +#define MS_LOWER_MAX_DB 8 /*! 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. @@ -51,10 +56,6 @@ int lchan_ms_pwr_ctrl(struct gsm_lchan *lchan, if (lchan->ms_power_ctrl.fixed) return 0; - /* How many dBs measured power should be increased (+) or decreased (-) - to reach expected power. */ - diff = bts->ul_power_target - rxLevel; - current_dbm = ms_pwr_dbm(band, ms_power); if (current_dbm < 0) { LOGPLCHAN(lchan, DLOOP, LOGL_NOTICE, @@ -70,6 +71,18 @@ int lchan_ms_pwr_ctrl(struct gsm_lchan *lchan, return 0; } + /* How many dBs measured power should be increased (+) or decreased (-) + to reach expected power. */ + diff = bts->ul_power_target - rxLevel; + + /* don't ever change more than MS_{LOWER,RAISE}_MAX_DBM during one loop + iteration, i.e. reduce the speed at which the MS transmit power can + change. A higher value means a lower level (and vice versa) */ + if (diff > MS_RAISE_MAX_DB) + diff = MS_RAISE_MAX_DB; + else if (diff < -MS_LOWER_MAX_DB) + diff = -MS_LOWER_MAX_DB; + new_dbm = current_dbm + diff; /* Make sure new_dbm is never negative. ms_pwr_ctl_lvl() can later on |