Distributed Time Synchronization in Wireless Sensor Networks with Coupled Discrete-Time Oscillators

• Main Authors: Spagnolini U, Simeone O
• Format: Article
• Language: English
• Published: SpringerOpen 2007-01-01
• Series: EURASIP Journal on Wireless Communications and Networking
• Online Access: http://jwcn.eurasipjournals.com/content/2007/057054

<p/> <p>In wireless sensor networks, distributed timing synchronization based on pulse-coupled oscillators at the physical layer is currently being investigated as an interesting alternative to packet synchronization. In this paper, the convergence properties of such a system are studied through algebraic graph theory, by modeling the nodes as discrete-time clocks. A general scenario where clocks may have different free-oscillation frequencies is considered, and both time-invariant and time-variant network topologies (or fading channels) are discussed. Furthermore, it is shown that the system of oscillators can be studied as a set of coupled discrete-time PLLs. Based on this observation, a generalized system design is discussed, and it is proved that known results in the context of conventional PLLs for carrier acquisition have a counterpart in distributed systems. Finally, practical details of the implementation of the distributed synchronization algorithm over a bandlimited noisy channel are covered.</p>