Throughput performance of a busy-tone protocol in CCA modified, long range IEEE 802.11 networks

Media access protocols define network performance in WLAN/WMAN systems. Such wireless networks are generally short range and use the CSMA (Carrier Sense Multiple Access) protocol which forms the basis to the ubiquitous IEEE 802.11 standard. In this paper we examine the behavior of a hybrid CSMA protocol called the ¿busy-tone protocol¿ which uses a dedicated physical channel to indicate media availability to a highly distributed, wide ranging (3-48 km) hidden set of mobile users. Using the busy tone to gate the radios, we force the radio link into a time domain duplex-like operation with the downlink channel consisting of scheduled concatenated bursts, effectively bypassing the CSMA, while the uplink channel still employs CSMA-like operation. The focus of the simulations is to understand performance of the proposed approach in long range, low S/N scenarios, and consider a hybrid IEEE 802.11 solution that would have improved performance compared to traditional applications of the standard.