  Neighbor discovery is a fundamental service for initialization and managing
network dynamics in wireless sensor networks and mobile sensing applications.
In this paper, we present a novel design principle named Talk More Listen Less
(TMLL) to reduce idle-listening in neighbor discovery protocols by learning the
fact that more beacons lead to fewer wakeups. We propose an extended neighbor
discovery model for analyzing wakeup schedules in which beacons are not
necessarily placed in the wakeup slots. Furthermore, we are the first to
consider channel occupancy rate in discovery protocols by introducing a new
metric to trade off among duty-cycle, latency and channel occupancy rate.
Guided by the TMLL principle, we have designed Nihao, a family of
energy-efficient asynchronous neighbor discovery protocols for symmetric and
asymmetric cases. We compared Nihao with existing state of the art protocols
via analysis and real-world testbed experiments. The result shows that Nihao
significantly outperforms the others both in theory and practice.
