Abstract. IEEE 802.11 MAC mainly relies on two techniques to combat interference: physical carrier sensing and RTS/CTS handshake (also known as "virtual carrier sensing"). Ideally, the RTS/CTS handshake can eliminate most interference. However, the effectiveness of RTS/CTS handshake is based on the assumption that hidden nodes are within transmission range of receivers. In this paper, we pmve using analytic models thati n ad hoc networks, such an wumption cannot hdd due to the fact that power needed for interrupting a packet reception is much lower than that of delivering a packet succesbully. Thus, the ''virtual carrier sensing" implemented by RTS/CTS handshake cannot prevent all interference. Physical carrier sensing can complement this in some degree However, sincei nterference happens at receivers, while physical carrier sensing is detecting transmitten (the same pmhlem causing theh idden terminal situation), physical eamer sensing cannot help much, nnless a very large carrier sensing range is adopted which is limited by the antenna sensitivity. In this paper, we investigate how effective is the RTSKTS handshake in terms of reducing interference. We show that in some situations, the interference range is much larger than transmission range, where RTS/CTS cannot function well. Then, a simple MAC layer scheme is proposed to solve this problem. Simulation results veri@ that our scheme can help IEEE 802.11 resolve most interference c a d hy large interference range.
The hidden node situation is partially, but not completely REF , addressed by the use of the RTS/CTS handshake before the DATA packet transmission.
How effective is the IEEE 802.11 RTS/CTS handshake in ad hoc networks
Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE
Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE
Computer Science