Wireless sensor networks have revealed vast potential in providing accurate and cost-effective monitoring for a plethora of applications. In stark contrast with traditional data forwarding networks exemplified by the Internet, wireless sensor networks are uniquely characterized by drastically low data rate, often at several bytes per minute, owing to application specific requirements. Despite numerous groundbreaking work in this field, the underlying communication techniques, particularly at the physical and link layers, are still largely germinating along the Internet root and its wireless extensions. Moreover, energy efficiency has overwhelmingly relied on coordinated sleep/wakeup schemes, where communications are synchronized into a short time window. Inevitably this will augment the collision probability and irrelevant packet listening, the two dominant power consumption components in wireless networks.
Motivated by recent advancements in semi-passive RFID technology, this project will develop an innovative asynchronous communication architecture, in which a sensor node is allowed to directly write data into a special, reactive module (RFID tag based) residing on the receiving node while its main platform (the central controller) is asleep. Owing to the low duty cycle of a sensor node, the proposed asynchronous architecture will liberate the network from collisions and idle listening by fully exploiting time as one dimension of resource (no conventional MAC needed) and hence achieve high energy efficiency. Furthermore, with this fundamentally new paradigm for communication in energy-constrained systems, this project will also study the overlaying computation paradigm, including sampling, in-network processing, and routing, in order to accommodate, fully unleash, and demonstrate its enormous impact.
