MAC Layer Approaches for Mitigating the Spectrum Underutilization Due to Overlapping BSS Problem in WLAN

Abstract

Overlapping basic service set (OBSS) interferences cause significant reductions in the network throughput as seen at the medium access control (MAC) layer. When the frequency bands of multiple OBSSs are partially overlapped, the reduction of throughput are worsened because in addition to the OBSS interference problem there arises the OBSS-induced spectrum underutilization problem which has not been addressed so far. In this paper, two complementary contention-based MAC layer schemes are proposed to solve the OBSS-induced spectrum underutilization problem by setting up a virtual-primary channel for contention. The proposed time-limited (TL) scheme is designed for transmitting long data packets, which is suitable for applications requiring high throughputs. In contrast, the multi-contention (MC) scheme is designed for transmitting short data packets, which is suitable for applications requiring short delays. By efficiently exploiting the OBSS-induced underutilized spectrum, simulation results verify that the proposed TL scheme can increase the throughput greatly and the proposed MC scheme can reduce the delay for short data packets significantly.