Advanced Hybrid Beamforming Design for MIMO Systems

One of the fundamental problems for hybrid beamformer design in MIMO systems is that, in Singular-Value-Decomposition (SVD) based beamforming, the analog beamformer is limited to constant modulus. In order to solve this issue, an algorithm is proposed in this paper. Specifically, the parallel data streams are expressed mathematically, and then the math expression of the analog beamformer is achieved through maximizing the power of desired data streams while minimizing the power of interference. Then, the digital part of the beamformer is calculated based on a channel equivalent process, i.e., considering the phase response vector of the derived analog beamformers as part of the channel observed by the digital beamformers. Simulations are performed on the proposed algorithm and compared to a recent state-of-the-art technique. The results show that the proposed one outperforms in terms of sphere of application (i.e., different antenna array sizes and channel sparsities).