Towards Deep Learning-Guided Multiuser SNR and Doppler Shift Detection for Next-Generation Wireless Systems

In order to meet the ever-growing demand for data traffic, highly efficient multiple access schemes, such as OFDMA, are widely used in modern communication standards. In such multiple access schemes, adaptive modulation and coding (AMC) are used to optimize the transmission rate of each user. However, feedback information, such as SNR and Doppler shift, characterizing the communication environment of each user is indispensable of key importance for AMC. In the past, these information and parameters were often estimated using reference signals. However, the reference signal becomes overhead, resulting in throughput degradation and processing delay. Furthermore, the computation burden can be large as it is necessary to perform channel parameter estimation individually for each user. Previously, over the single-user channel, we have proposed a joint SNR and Doppler shift detection method via a spectrogram-based data-driven method, without the reference signal. This paper extends this framework to multiuser OFDM multiple access channels. In the newly proposed method, SNR and Doppler shift for all users can be detected simultaneously via deep learning-guided object detection algorithms from each spectrogram image. Simulation results are provided to validate the effectiveness of the proposed method.