MAC Protocol Using Asynchronous Multi-Channels in Ad Hoc Networks

In this paper, we consider a simple but efficient medium access control (MAC) protocol that can be used in an ad hoc network with asynchronous multi-channel environments. The approach in our proposal is to use time offset between channels where each channel has its own frame starting time. We assume that the network runs in power saving mode (PSM) of the IEEE 802.11 standard protocol which channel structure consists of beacon frame, ad hoc traffic indication message (ATIM) window, and data window. By asynchronizing beacon frame start times between channels, nodes that have no tasks involved in the current channel can switch to some other channels for more consecutive data transmission trials. Through extensive simulations, we confirm that our multi-channel access scheme results in significant throughput enhancement compared to the conventional access scheme that uses multi-channels in a synchronized manner. Combining our proposal with a power saving scheduling algorithm, we can achieve further throughput improvement. Our analysis and simulation results are used to prove the advantage of our proposals.