Performance Analysis and Energy Optimization of Wake-Up Receiver Schemes for Wireless Low-Power Applications

Abstract

The use of duty-cycled ultralow-power wake-up receivers (WRxs) can significantly extend a node lifetime in low-power sensor network applications. In the WRx design, both the low-power operation of the WRx and the wake-up beacon (WB) detection performance are of importance. We present a system-level analysis of a duty-cycled WRx design, including an analog front end, a digital baseband, the WB structure, and the resulting WB detection and false-alarm probabilities. We select a low-power WRx design with about two orders of magnitude lower power consumption than the main receiver. The associated cost is an increase in the raw bit error rate (BER), as compared with the main receiver, at the same received power level. To compensate, we use a WB structure that employs spreading. The WB structure leads us to an architecture for the digital baseband with high address-space scalability. We calculate closed-form expressions for detection and false-alarm probabilities. Using these, we analyze the impact of design parameters. The analytical framework is exemplified by the minimization of the WB transmit energy. For this particular optimization, we also show that the obtained results are valid for all transmission schemes with an exponential relationship between the signal-to-noise ratio and the BER, e.g., the binary orthogonal schemes with noncoherent detection used in many low-power applications.