A two-level carrier sensing mechanism for overlapping BSS problem in WLAN

Basic service set (BSS) is the fundamental building block of an IEEE 802.11 wireless local area network (WLAN). The overlapping BSS problem refers to situations that two or more systems, unrelated to each other, are in close enough proximity to hear each other physically. Overlapping BSS problem may degrade the network performance severely. In this paper, a two-level carrier sensing mechanism is proposed to solve the overlapping BSS problem. In the proposed solution, a new network allocation vector is introduced to solve the overlapping BSS problem with minimal hardware requirement. Moreover, the proposed mechanism introduces very little complexity - when there is no overlapping BSS problem exists, the proposed mechanism works the same as legacy 802.11 MAC mechanism