Have Your Cake and Eat It Too! Enabling Frequency Diversity Through Opportunism
The broadcast nature of wireless networks is both a boon and a bane. On the one hand, multiple receivers may overhear a single transmission on the same channel at no additional cost above a point-to-point transmission; this property has been exploited in many opportunistic applications (e.g., ). On the other hand, the shared nature of the medium eﬀectively forces wireless nodes to leverage frequency diversity and channelization for eﬃciency. Unfortunately, coordinating communication between nodes that may switch channels at any time is diﬃcult and may in fact oﬀset any performance gains from leveraging frequency diversity. In this paper, we describe lazily-assisted channel hopping (LACH) which utilizes opportunism to enable more frequency diversity. LACH consists of two techniques: ﬂexible channel hopping, which gives nodes nearly complete freedom in switching channels in order to efficiently leverage available channels; and lazy opportunistic gossip, which helps nodes ﬁnd one another by having nodes gossip schedules when unacknowledged transmissions are opportunistically overheard. Through these techniques, LACH enables nodes to dynamically adjust to diverse workloads, ﬂexibly allocate their bandwidth, and eﬃciently ﬁnd other nodes of interest.