diff options
Diffstat (limited to 'net/mac80211/rc80211_minstrel.h')
| -rw-r--r-- | net/mac80211/rc80211_minstrel.h | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h index 9c85a610b57b..c230bbe93262 100644 --- a/net/mac80211/rc80211_minstrel.h +++ b/net/mac80211/rc80211_minstrel.h @@ -35,6 +35,24 @@ minstrel_ewma(int old, int new, int weight) return old + incr; } +/* + * Perform EWMSD (Exponentially Weighted Moving Standard Deviation) calculation + */ +static inline int +minstrel_ewmsd(int old_ewmsd, int cur_prob, int prob_ewma, int weight) +{ + int diff, incr, tmp_var; + + /* calculate exponential weighted moving variance */ + diff = MINSTREL_TRUNC((cur_prob - prob_ewma) * 1000000); + incr = (EWMA_DIV - weight) * diff / EWMA_DIV; + tmp_var = old_ewmsd * old_ewmsd; + tmp_var = weight * (tmp_var + diff * incr / 1000000) / EWMA_DIV; + + /* return standard deviation */ + return (u16) int_sqrt(tmp_var); +} + struct minstrel_rate_stats { /* current / last sampling period attempts/success counters */ u16 attempts, last_attempts; @@ -45,9 +63,11 @@ struct minstrel_rate_stats { /* statistis of packet delivery probability * cur_prob - current prob within last update intervall - * prob_ewma - exponential weighted moving average of prob */ + * prob_ewma - exponential weighted moving average of prob + * prob_ewmsd - exp. weighted moving standard deviation of prob */ unsigned int cur_prob; unsigned int prob_ewma; + u16 prob_ewmsd; /* maximum retry counts */ u8 retry_count; |