reduced interframe space (RIFS)

In general, the Interframe Space( IFS) is a period of time to ensure that all previous activities, for example in CSMA/ CA, are completed and can no longer affect functionality.

Reduced Interframe Space (RIFS) is a technique used in WLANs with High Throughput( HT). RIFS space was introduced in 802.11n WLANs to increase efficiency.

In the RIFS technique, a frameseparator shortens the interframe space and thus ensures better use of the available airtime when two high throughput clients communicate with each other. With high-throughput (HT) technology, the interframe space is shortened to 2 µs, which is much shorter than the short interframe space( SIFS) period, which is 10 µs in the 2.4 GHz band and 16 µs in the 5 GHz band.

The RIFS space is not used in WLANs according to 802.11ac.