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fixeria gerrit-no-reply at lists.osmocom.orgfixeria has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-bts/+/21907 ) Change subject: power_control: generalize the arguments of do_pf_ewma() ...................................................................... power_control: generalize the arguments of do_pf_ewma() This way EWMA based filtering can also be applied to RxQual. Change-Id: I439c00b394da670e314f217b3246cc85ce8213c6 Related: SYS#4918, SYS#4917 --- M src/common/power_control.c 1 file changed, 13 insertions(+), 17 deletions(-) git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/07/21907/1 diff --git a/src/common/power_control.c b/src/common/power_control.c index a616f18..9e6fb45 100644 --- a/src/common/power_control.c +++ b/src/common/power_control.c @@ -38,29 +38,29 @@ /* Base Low-Pass Single-Pole IIR Filter (EWMA) formula: * - * Avg[n] = a * Pwr[n] + (1 - a) * Avg[n - 1] + * Avg[n] = a * Val[n] + (1 - a) * Avg[n - 1] * * where parameter 'a' determines how much weight of the latest UL RSSI measurement - * result 'Pwr[n]' carries vs the weight of the average 'Avg[n - 1]'. The value of + * result 'Val[n]' carries vs the weight of the average 'Avg[n - 1]'. The value of * 'a' is usually a float in range 0 .. 1, so: * - * - value 0.5 gives equal weight to both 'Pwr[n]' and 'Avg[n - 1]'; + * - value 0.5 gives equal weight to both 'Val[n]' and 'Avg[n - 1]'; * - value 1.0 means no filtering at all (pass through); * - value 0.0 makes no sense. * * Further optimization: * - * Avg[n] = a * Pwr[n] + Avg[n - 1] - a * Avg[n - 1] + * Avg[n] = a * Val[n] + Avg[n - 1] - a * Avg[n - 1] * ^^^^^^ ^^^^^^^^^^ * * a) this can be implemented in C using '+=' operator: * - * Avg += a * Pwr - a * Avg - * Avg += a * (Pwr - Avg) + * Avg += a * Val - a * Avg + * Avg += a * (Val - Avg) * * b) everything is scaled up by 100 to avoid floating point stuff: * - * Avg100 += A * (Pwr - Avg) + * Avg100 += A * (Val - Avg) * * where 'Avg100' is 'Avg * 100' and 'A' is 'a * 100'. * @@ -70,20 +70,15 @@ * https://en.wikipedia.org/wiki/Low-pass_filter#Simple_infinite_impulse_response_filter * https://tomroelandts.com/articles/low-pass-single-pole-iir-filter */ -static int8_t do_pf_ewma(const struct bts_power_ctrl_params *params, - struct lchan_power_ctrl_state *state, - const int8_t Pwr) +static int do_pf_ewma(int *Avg100, const int Val, const uint8_t A) { - const uint8_t A = params->pf.ewma.alpha; - int *Avg100 = &state->avg100_rxlev_dbm; - /* We don't have 'Avg[n - 1]' if this is the first run */ if (*Avg100 == 0) { - *Avg100 = Pwr * EWMA_SCALE_FACTOR; - return Pwr; + *Avg100 = Val * EWMA_SCALE_FACTOR; + return Val; } - *Avg100 += A * (Pwr - *Avg100 / EWMA_SCALE_FACTOR); + *Avg100 += A * (Val - *Avg100 / EWMA_SCALE_FACTOR); return *Avg100 / EWMA_SCALE_FACTOR; } @@ -99,7 +94,8 @@ /* Filter input value(s) to reduce unnecessary Tx power oscillations */ switch (params->pf_algo) { case BTS_PF_ALGO_EWMA: - rxlev_dbm_avg = do_pf_ewma(params, state, rxlev_dbm); + rxlev_dbm_avg = do_pf_ewma(&state->avg100_rxlev_dbm, rxlev_dbm, + params->pf.ewma.alpha); break; case BTS_PF_ALGO_NONE: default: -- To view, visit https://gerrit.osmocom.org/c/osmo-bts/+/21907 To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: osmo-bts Gerrit-Branch: master Gerrit-Change-Id: I439c00b394da670e314f217b3246cc85ce8213c6 Gerrit-Change-Number: 21907 Gerrit-PatchSet: 1 Gerrit-Owner: fixeria <vyanitskiy at sysmocom.de> Gerrit-MessageType: newchange -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.osmocom.org/pipermail/gerrit-log/attachments/20201230/faf0d444/attachment.htm>