Weighted aggregation scheme with lifetime-accuracy tradeoff in wireless sensor network

We consider design of wireless sensor network for event detection application. An MMSE based q-bit weighted aggregation scheme (q-WAS) is proposed in which each node transmits q bits to its parent in every session. The observation of each sensor is assumed to be one bit. The simulation results sow that 1-WAS achieves better accuracy than a previously proposed one bit aggregation scheme while offering almost same lifetime. With increasing q, the accuracy of q-WAS approaches that of the infinite precision aggregation scheme. Moreover the lifetime for q-WAS is significantly higher than infinite precision aggregation scheme. For a 100 node sensor network, the simulation results show that 3-WAS achieves a near optimum accuracy. The lifetime of the q-WAS is approximately 1/q-th of the lifetime of the one bit aggregation schemes. Hence this class of aggregation schemes offers a trade-off between accuracy and lifetime

MAAS : Multibit Adaptive Aggregation Scheme for wireless sensor networks

The problem of data aggregation for binary event detection using wireless sensor networks has been considered in the present work. We propose a novel Multibit Adaptive Aggregation Scheme (MAAS) which combines the merits Of both multibit and adaptive aggregation schemes. Firstly, being adaptive, the proposed scheme does not require knowledge of the performance indices of sensor nodes as required by the existing optimum decision fusion rule. Therefore, in case of small variations in the topology or performance indices, the proposed scheme needs to just fine time the weights starting from the previously adapted weights, instead of seeking new values of the parameters or recomputing the initial setup. Secondly, being a multibit aggregation scheme, the performance of the proposed MAAS is higher than the existing single-bit aggregation schemes at a cost of communicating only a few extra bits. This makes it suitable for event detection applications where detection accuracy is more important than the energy drained in communicating a few additional bits. Further the performance of the proposed MAAS is shown to be consistently superior to single-bit schemes even in the presence of Rayleigh fading channel