Low-Power RF Wake-Up Receivers: Analysis, Tradeoffs, and Design

Wake-up receivers (WuRXs) offer a potentially energy-efficient means to enable asynchronous wake-up of higher-power and higher-performance radios without needing frequent (often energy-expensive) synchronization. Since WuRXs are typically on for a large percentage of the time, keeping their power consumption very low is critical to minimizing total energy draw. However, this is difficult while maintaining good sensitivity, interference resiliency, and robustness, all with application-appropriate wake-up latencies and form factors. This article reviews the main challenges facing WuRXs, outlines the most popular WuRX architectures, and details essential design techniques and trade-offs towards enabling utility in emerging applications.