Authors: Chih-Yu Lin; Yu-Chee Tseng; Ten H. Lai
Addresses: Gogolook Inc, Taipei, 107, Taiwan. ' Department of Computer Science, National Chiao-Tung University, Hsin-Chu, 300, Taiwan. ' Department of Computer Science and Engineering, The Ohio State University, Columbus, Ohio 43210 USA
Abstract: Wireless Sensor Networks (WSNs) can generally be classified into two categories: time-driven and event-driven. In an event-driven WSN, sensors report their readings only when they detect events. In such behaviour, sensors in the event area may suffer from higher contention. In this paper, we solve this problem by jointly considering two sub-issues. One is exploiting the spatial correlation of sensor data and the other is designing a specific MAC protocol. We propose a novel hybrid TDMA/CSMA protocol with the following interesting features that differentiate itself from traditional TDMA-based protocols: (1) the TDMA part is based on very loose time synchronisation and is triggered by the appearance of events; (2) the slot assignment strategy associated with the TDMA part takes the spatial correlation of sensor data into consideration and thus allows less strict slot allocation than conventional TDMA schemes. Simulation results show the efficiency of the proposed protocol.
Keywords: wireless sensor networks; WSNs; medium access control; MAC; TDMA; CSMA; spatial correlation; link layers; event-driven sensor networks; wireless networks; simulation.
International Journal of Sensor Networks, 2012 Vol.12 No.1, pp.1 - 15
Accepted: 20 Jan 2012
Published online: 08 Jul 2012 *