PCQNet: A Trainable Feedback Scheme of Precoder for the Uplink Multi-User MIMO Systems

• Published in: Entropy (Basel, Switzerland) Vol. 24; no. 8; p. 1066
• Main Authors: Bao, Xiuwen, Jiang, Ming, Fang, Wenhao, Zhao, Chunming
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2022; MDPI
• Subjects: Compression ratio; Control; convolutional neural networks (CNNs); Decomposition; Deep learning; Design and construction; Efficiency; Error analysis; Feedback; Feedback control systems; Iterative algorithms; Iterative methods; joint transceiver design; Lagrange multiplier; limited feedback precoding; Machine learning; Methods; MIMO; MIMO communication; MIMO communications; MMSE receivers; Neural networks; Optimization; Performance degradation; Sensors; Technology application; uplink precoding; Uplinking; Wireless networks; China
• ISSN: 1099-4300; 1099-4300
• DOI: 10.3390/e24081066

Multi-user multiple-input multiple-output (MU-MIMO) technology can significantly improve the spectral and energy efficiencies of wireless networks. In the uplink MU-MIMO systems, the optimal precoder design at the base station utilizes the Lagrange multipliers method and the centralized iterative algorithm to minimize the mean squared error (MSE) of all users under the power constraint. The precoding matrices need to be fed back to the user equipment to explore the potential benefits of the joint transceiver design. We propose a CNN-based compression network named PCQNet to minimize the feedback overhead. We first illustrate the effect of the trainable compression ratios and feedback bits on the MSE between the original precoding matrices and the recovered ones. We then evaluate the block error rates as the performance measure of the centralized implementation with an optimal minimum mean-squared error (MMSE) transceiver. Numerical results show that the proposed PCQNet achieves near-optimal performance compared with other quantized feedback schemes and significantly reduces the feedback overhead with negligible performance degradation.