As an essential element in the future information infrastructure, wireless sensing systems have motivated a huge amount of research interests in the community. Such efforts are critical to building the bridge between the physical world and the cyber world, where physical system parameters such as voltage/current levels in a power grid, temperature/humidity levels over a farming field, and stress levels across a bridge could be collected and processed for automatic cyber control. However, it is still an open problem on how to find the optimal way of conveying information over such sensor networks, since there is a lack of well-defined optimality criteria for end-to-end information collection, transmission, and processing. In this project, the PI first proposes new optimality criteria based on novel network-wise multiplexing diversity tradeoff analysis, then studies the efficient information transmission and processing schemes, with special considerations on network non-ergodicity in hostile application environments. The proposed research will have great multi-fold impacts on our society. The sensing system design results will enable various key applications such as complex cyber-physical system monitoring and large-scale real-time environment surveillance. The fundamental performance analysis developed for sensor networks could also be applied to other types of networks beyond the sensing applications. The proposed program will broaden the education scope in the society by providing training to students, enhancing school curriculum, holding regular seminars, posting results on the project website, and presenting papers in technical conferences. It will also emphasize the outreaches to women and under-represented groups.
Specifically, in this program, the PI starts by addressing one fundamental problem in wireless sensing system design: Given M unknown entities (sources) to sense by a network of N wireless sensing nodes operating with certain resources in power, time, frequency, and space, what the fundamental tradeoffs will be among the supportable M, the achievable end-to-end reliability, and the required network resources. Non-ergodic random communication channels and non-ergodic random node losses are jointly considered. Both cases of correlated and uncorrelated sources are thoroughly studied. Motivated by the multiplexing and diversity tradeoff result in multi-antenna transmission systems, the concept of multiplexing and diversity tradeoff is redefined as the optimality criteria in the distributed sensor network context. The emphasis of this project is quantifying the fundamental achievable tradeoffs among various entities of interest, and proposing efficient information transmission and processing schemes to achieve some particular operation points on the optimal tradeoff curves, with special considerations over the non-ergodic natures of random sensor networks in various applications. The deliverables include basic theories, performance bounds, and optimal sensing schemes. The intellectual merits lie in the systematic treatment over core design issues in wireless sensing systems operating for applications with non-ergodic network randomness. Transformative new concepts based on estimation/detection outage and estimation/detection diversity are thoroughly investigated and generalized to cases involving correlated sources, multi-hop networks, and multiple fusion centers.
