diff --git a/sys/net80211/ieee80211_phy.h b/sys/net80211/ieee80211_phy.h
index 9e1f532ec3d4..56b404f7792b 100644
--- a/sys/net80211/ieee80211_phy.h
+++ b/sys/net80211/ieee80211_phy.h
@@ -104,6 +104,12 @@ ieee80211_rate2phytype(const struct ieee80211_rate_table *rt, uint8_t rate)
 	return rt->info[rix].phy;
 }
 
+static __inline__ int
+ieee80211_isratevalid(const struct ieee80211_rate_table *rt, uint8_t rate)
+{
+	return rt->rateCodeToIndex[rate] != (uint8_t)-1;
+}
+
 /*
  * Calculate ACK field for
  * o  non-fragment data frames