On scheduling without a master clock: Coupled Oscillator Time Division Multiplexing

Abstract

Most scheduled communication systems rely on either central coordination, or on the presence of an external reference clock that is accessible to all nodes in the network. Such requirements often limit the scalability and applicability of time division multiple access (TDMA) solutions to ad-hoc networks, which largely rely on conflict resolution based on random access mechanism. We show that, by borrowing mechanisms of coordination found in nature, we can self-organize nodes in a network in time division without a central clock, nor a common reference signal. We show that a common clock reference and a conflict free schedule can emerge from our signaling control scheme, using simple local computations that are based on the so called Pulse Coupled Oscillator (PCO) dynamics. Compared to the prior art on PCO, our work provides an integrated solution for network synchronization and collision free TDMA that is completely decentralized and can lead to efficient transmission of data at a regular and reliable pace. We discuss how this scheme can be used to provide an alternative to the popular Zigbee interface, and produce collision free clustered synchronous networks.

Analysis and Design of Phase Desynchronization in Pulse-coupled Oscillators

“…A modified algorithm V-DESYNC was proposed in [22] to mitigate the beacon collision problem by randomly adding a small offset to the firing time. The authors in [18], [23] proposed a phase desynchronization algorithm by limiting the listening interval. The authors in [24] obtained phase desynchronization by adding an anchored PCO that never adjusts its phase when other PCOs fire.…”