Data acquisition with RF-based energy harvesting sensor: From information theory to green system

Harvesting energy from ambient environment is a new promising solution to free electronic devices from electric wire or limited-lifetime battery, which is significant in sensor networks and body-area networks. This paper investigates the fundamental limits of information transmission in data acquisition system with RF-based energy harvesting sensor node, in which the host node acts not only as an information source but also as an energy source for the sensor node while only information is transmitted back from sensor to host node. From a view of system level, achievable capacity-rate region and capacity-rate function are proposed as metrics to measure the transmission performance. The tradeoff relationship of two way information rates between sensor and host node in a time division duplex system is obtained and the corresponding optimal transmission policy is also given. At last, a typical application in terms of minimizing required transmit power, namely green system, is introduced to validate the results developed in this paper.