BitSNNs: Revisiting Energy-Efficient Spiking Neural Networks

To address the energy bottleneck in deep neural networks (DNNs), the research community has developed binary neural networks (BNNs) and spiking neural networks (SNNs) from different perspectives. To combine the advantages of both BNNs and SNNs for better energy efficiency, this article proposes BitSNNs, which leverage binary weights, single-step inference, and activation sparsity. During the development of BitSNNs, we observed performance degradation in deep ResNets due to the gradient approximation error. To mitigate this issue, we delve into the learning process and propose the utilization of a hardtanh function before activation binarization. Additionally, this article investigates the critical role of activation sparsity in BitSNNs for energy efficiency, a topic often overlooked in the existing literature. Our study reveals strategies to strike a balance between accuracy and energy consumption during the training/testing stage, potentially benefiting applications in edge computing. Notably, our proposed method achieves state-of-the-art performance while significantly reducing energy consumption.