Figure based on [1]
Figure based on [1]

In a typical biosignal monitoring application pipeline, the biosignal is captured by sensors on the patient’s body and forwarded as input to the application processing. Typically, the processing step consists of signal preprocessing (i.e., filtering), feature extraction(i.e., time or frequency characteristics), and inference(i.e., ML model) based on these features. However, applications can exhibit a wide range of workloads and computational requirements. For example, feature extraction can be implemented explicitly (that is, manually engineered features) or implicitly (e.g., convolutional neural network (CNN)). Similarly, the inference step can use a lightweight machine learning method, such as a random forest or a computationally intensive deep neural network (DNN).

MCU operating phases

The system undergoes an always-on acquisition phase and an intermittent processing phase, as presented in the figure above. A whole processing period consists of an idle period, during which the processing unit is in low-power mode, and a computation upon acquisition of the full input signal. The duration of the idle period can vary significantly between applications and can dominate the system’s energy consumption. Considering the variety of workloads and idle-to-active ratios, a benchmark suite that covers a wide range of applications is an essential tool for hardware evaluation in the biomedical domain.