A wake-up receiver with ad-hoc antenna co-design for wearable applications

Description

Body Area Networks (BAN) have received significant attention in recent years and have found a wide range of applications, including wearable devices for fitness and health tracking, and mobile communications. Battery lifetime continues to be the main bottleneck in these small form factor devices, thus low power design and advanced power management techniques are required to sustain the increasing demands on power. As radio transceivers are typically the most power hungry subsystem in a wearable sensors device, optimizations to reduce the communication power consumption, such as using adaptive power management coupled with ultra-low power receivers have been widely investigated. In this work, we focus on the design of a novel wearable wake-up radio consuming only few nW during listening mode, significantly reducing the overall power consumption of communication, which enables aggressive power management techniques. We propose the co-design of an ad-hoc wearable antenna which directly matches the impedance of the analog frontend in order to improve the performance in terms of sensitivity and directivity in BAN context. Our novel wake up radio consumes only 400nW while providing short-range communication, and features on board addressing capability to further reduce the power due to false wake ups. Using in-field measurements, we evaluate the benefits of the ad-hoc antenna compared to state-of-the-art off-the-shelf solutions in terms of range, sensitivity and addressing capability. We quantify energy savings and estimate the lifetime prolongation of the sensor node by integrating our wake-up radio in a wearable system.

Abstract

International audience

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