Efficient Execution of Temporal Convolutional Networks for Embedded Keyword Spotting

Recently, the use of keyword spotting (KWS) has become prevalent in mobile devices. State-of-the-art deep learning algorithms such as temporal convolutional networks (TCNs) have been applied to this task achieving superior accuracy results. These models can, however, be mapped in multiple ways onto embedded devices, ranging from real-time streaming inference with or without computational sprinting to delayed batched inference. Although functionally equivalent, these deployment settings, however, strongly impacts average power consumption and latency of this real time task, hence requiring a thorough optimization. This work analyzes the challenges, benefits, and drawbacks of the different execution modes available for TCN-based KWS inference on dedicated hardware. With this objective, this research contributes to: 1) presenting a complete deep learning accelerator optimized for TCN inference; 2) evaluating the impact on performance and power of the different deployment options for TCN inference applied to KWS obtaining up to 8 μW for real-time operation; and 3) optimizing real-time power consumption for KWS inference by exploiting the use of cascaded neural networks (NNs), achieving up to 35% additional power savings.