Sub-mW Keyword Spotting on an MCU: Analog Binary Feature Extraction and Binary Neural Networks
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Abstract (arXiv)
Keyword spotting (KWS) is a crucial function enabling the interaction with the many ubiquitous smart devices in our surroundings, either activating them through wake-word or directly as a human-computer interface. For many applications, KWS is the entry point for our interactions with the device and, thus, an always-on workload. Many smart devices are mobile and their battery lifetime is heavily impacted by continuously running services. KWS and similar always-on services are thus the focus when optimizing the overall power consumption. This work addresses KWS energy-efficiency on low-cost microcontroller units (MCUs). We combine analog binary feature extraction with binary neural networks. By replacing the digital preprocessing with the proposed analog front-end, we show that the energy required for data acquisition and preprocessing can be reduced by 29x, cutting its share from a dominating 85% to a mere 16% of the overall energy consumption for our reference KWS application. Experimental evaluations on the Speech Commands Dataset show that the proposed system outperforms state-of-the-art accuracy and energy efficiency, respectively, by 1% and 4.3x on a 10-class dataset while providing a compelling accuracy-energy trade-off including a 2% accuracy drop for a 71x energy reduction.
Key facts. Cited by 5 papers in the map (data through 7 Oct 2026). Builds on 23 of its 52 references that are in the map. First posted on arXiv 10 Jan 2022.
Builds on
23 of 52 references.
References · 23
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11 more
- 2017A Cascade Architecture for Keyword Spotting on Mobile Devicescited by 15
- 2021Sound Event Detection with Binary Neural Networks on Tightly Power-Constrained IoT Devicescited by 10
- 2020CUTIE: Beyond PetaOp/s/W Ternary DNN Inference Acceleration with Better-than-Binary Energy Efficiencycited by 8
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Citing papers per year: 2024: 1; 2025: 4.
5 papers.
- 2024xTern: Energy-Efficient Ternary Neural Network Inference on RISC-V-Based Edge Systemscited by 4
- 2025Efficient Continual Learning in Keyword Spotting using Binary Neural Networkscited by 2
- 2025Adaptive Noise Resilient Keyword Spotting Using One-Shot Learningcited by 1
- 2025Implementing Keyword Spotting on the MCUX947 Microcontroller with Integrated NPUcited by 1
- 2025LearnAFE: Circuit-Algorithm Co-design Framework for Learnable Audio Analog Front-Endcited by 0
- 2025LearnAFE: Circuit-Algorithm Co-design Framework for Learnable Audio Analog Front-End1 Jul 2025
- 2025Implementing Keyword Spotting on the MCUX947 Microcontroller with Integrated NPU10 Jun 2025
- 2025Adaptive Noise Resilient Keyword Spotting Using One-Shot Learning14 May 2025
- 2025Efficient Continual Learning in Keyword Spotting using Binary Neural Networks5 May 2025
- 2024xTern: Energy-Efficient Ternary Neural Network Inference on RISC-V-Based Edge Systems29 May 2024