An Improved Busy-Tone Solution for Collision Avoidance in Wireless Ad Hoc Networks

In a single-channel wireless ad hoc network, the collisions caused by hidden terminals can severely reduce the network capacity. In this paper, a new busy-tone based scheme is proposed, which can completely avoid collisions (including DATA packet and RTS packet collisions) caused by hidden terminals. This is achieved by adding dual busy-tone channels, and setting a larger carrier sense range of the transmitter busy-tone channel than those of the information and receiver busy-tone channels. The proposed scheme also resolves the exposed terminal problem incurred by the increased carrier sense range of the transmitter busy-tone channel. The simulation results demonstrate that the proposed scheme has an improved performance in terms of throughput in the hidden terminal scenario as compared with the traditional busy-tone solution, and also achieves a high channel utilization in the exposed terminal scenario.