More the Merrier: Neighbor Discovery on Duty-Cycled Mobile Devices in Group Settings

Neighbor discovery on duty-cycled mobile devices in group settings arises in many applications. In such scenarios, it is sufficient for an arbitrary node in a group to discover a new node. While pairwise neighbor discovery schemes can be directly applied to group settings, their performance can be severely limited as they are not designed to coordinate the efforts of group members. Explicit coordination among the group members, however, can incur large overhead in mobile networks, where the group membership changes dynamically over time. In this paper, we focus on schemes that require no explicit communication among the group members, and nodes follow deterministic schedules that can be succinctly represented. We first define the notion of ideal duty cycle for a group, and then develop two deterministic neighbor discovery schemes for group settings, and show that both of them achieve effective duty cycle close to the ideal duty cycle. In addition, we show that the schemes are lightweight and easy to implement using experiments in a testbed. Last, we use a case study to demonstrate the usage of our proposed schemes and show that a simple enhancement leveraging the deterministic nature of the schemes leads to significant performance improvement, at the cost of only slight extra overhead.