overlapping basic service set (OBSS)

Overlapping Basic Service Set (OBSS) is a problem that reduces the network performance of WLANs. In overlapping BSS, two or more access points or WLAN stations installed close together and operating on the same transmission channel that have no connection to each other interfere with each other. They can receive frames from the neighboring station.

Overlapping BSS occurs much more frequently in broadband WLANs. This is due to the higher bandwidths of 40 MHz, 80 MHz and 160 MHz as in 802.11ac, and to the increasing number of WLAN devices competing with each other for radio access. Therefore, approaches need to be sought to increase the performance of overlapping access points in terms of capacity sharing.

One approach to reduce OBSS interference is an algorithm with a Quiet Element as specified in IEEE 802.11 (2007). During the specified Quiet Time, no radio transmission takes place in the corresponding channel.

Another technique with which the mobile terminals can distinguish basic service sets is BSS coloring, which has already been introduced in WLANs according to 802.11ah.