PECL: A Heterogeneous Parallel Multi-Domain Network for Radar-Based Human Activity Recognition

Abstract--Radar systems are increasingly favored for medical applications because they provide non-intrusive monitoring with high privacy and robustness to lighting conditions. However, existing research typically relies on single-domain radar signals and overlooks the temporal dependencies inherent in human activity, which complicates the classification of similar actions. PECL combines a channel-spatial attention module and temporal units to capture more features and dynamic dependencies during action sequences, improving both accuracy and robustness. The experimental results show that PECL achieves an accuracy of 96.16% on the same dataset, outperforming existing methods by at least 4.78%. PECL also performs best in distinguishing between easily confused actions. Despite its strong performance, PECL maintains moderate model complexity, with 23.42M parameters and 1324.82M Its parameter-efficient design further reduces computational cost. Human activity recognition (HAR) has long been an active research area. With the acceleration of population aging, demand for HAR technology is growing in both hospitals and households [1][2][3].