Max-min fair collision-free scheduling for wireless sensor networks

When the data rates in sensor networks are comparable to the available channel bandwidth, traditional randomized access schemes face the problem of energy inefficiency and reduced throughput due to increased MAC collisions as well as the problem of unfair data delivery. We argue that under such conditions it is preferable to focus on techniques for scheduled access. We present a linear programming formulation and corresponding distributed TDMA-based scheduling algorithms to provide max-min fair collision-free bandwidth allocation to all sources. We evaluate the performance of the proposed scheduled flow technique using the Tossim/Nido network simulator for the Berkeley Mote/TinyOS platform. Our results show that under high data rate conditions, the proposed scheme significantly outperforms randomized access based schemes in terms of key metrics such as fairness, energy efficiency, throughput, and delay.