Lightweight Neural Networks for Speech Emotion Recognition using Layer-wise Adaptive Quantization

Speech Emotion Recognition (SER) systems are essential in advancing human-machine interaction. While deep learning models have shown substantial success in SER by eliminating the need for handcrafted features, their high computational and memory requirements, alongside intensive hyper-parameter optimization, limit their deployment on resource-constrained edge devices. To address these challenges, we introduce an optimized and computationally efficient Multilayer Perceptron (MLP)-based classifier within a custom SER framework. We further propose a novel, layer-wise adaptive quantization scheme that compresses the model by adjusting bit-width precision according to layer importance. This layer importance is calculated based on statistical measures such as parameter proportion, entropy, and weight variance within each layer. Our approach achieves an optimal balance between model size reduction and performance retention, ensuring that the quantized model maintains accuracy within acceptable limits. Traditional fixed-precision methods, while computationally simple, are less effective at reducing model size without compromising performance. In contrast, our scheme provides a more interpretable and computationally efficient solution. We evaluate the proposed model on standard SER datasets using features such as Mel-Frequency Cepstral Coefficients (MFCC), Chroma, and Mel-spectrogram. Experimental results demonstrate that our adaptive quantization method achieves performance competitive with state-of-the-art models while significantly reducing model size, making it highly suitable for deployment on edge devices.