On Utilizing Directional Antenna in 802.11 Networks: Deafness Study

This paper presents a performance study of the deafness effect caused by the use of directional antenna in 802.11 networks. We show that different assumptions on antenna and channel model lead to different conclusions on the impact of deafness on network performance. Specifically, it is shown that in the presence of channel scatters between the transmitter and the receiver, directional antenna does not pose significant deafness and performance degradation. We also show that there always exists a CCA (clear-channel-assessment) threshold that eliminates deafness completely, even under existing 802.11 MAC protocols.