PCA-BD-Based Broadband Hybrid Precoding for Multi-user Massive MIMO Systems

Hybrid precoding has shown to be an effective method in massive multiple-input multiple-output (MIMO) systems. To enable the design of hybrid precoding in multi-user massive MIMO-OFDM systems, a principal component analysis (PCA) and block diagonalization (BD) based precoding method is proposed in this paper.In particular, to mitigate the frequency-selective characteristic of broadband channel and eliminate the interference in multi-user scenarios, the proposed design of hybrid precoding can be divided into two steps.First, relying on PCA, the frequency-flat universal radio frequency (RF) precoder is extracted from a set of frequency-selective RF precoders, which enables the design of RF precoder/combiner. Next, the baseband precoder/combiner is designed accordingly with the help of BD, which can eliminate interference effectively. Simulation results demonstrate the superiority of our proposed solution when compared to the state-of-the-art schemes in terms of sum spectral efficiency (SSE), bit error rate (BER) performance and the robustness to channel disturbances.