To enable next-generation mmWave cellular, it is vital to design high-performance precoding schemes for wideband multi-user (wMU) mmWave massive MIMO (mMIMO). As existing approaches are mostly ad-hoc, thereby lacking performance guarantee, we will tailor an enhanced transceiver design explicitly for wMU mmWave mMIMO, with the goal of maximizing mutual information (MI). The proposed scheme follows the prevalent hybrid block diagonalization (HBD-)based framework that is well-known for balancing the transmitter-end processing flexibility and the user-end detection complexity. In this paper, we for the first time prove that HBD is optimal in the sense of MI. In terms of the transceiver design, we start by decoupling the hybrid processing into a two-stage analog and digital processing, and then derive the MI bounds associated with HBD. By optimizing the tight MI bound, excellent HBD transceivers are devised for both the multi-aperture structure (MAS) and the multi-beam structure (MBS). The proposed HBD technique does not rely on substantial computational complexity, striking channel sparsity, or high-resolution analog beamformers, and can achieve a superb MI performance even with inferior hardware configurations.
Bibliographical noteFunding Information:
Manuscript received October 5, 2020; revised December 18, 2020; accepted January 13, 2021. Date of publication January 25, 2021; date of current version May 18, 2021. This work was supported in part by Ministry National Key Research and Development Project under Grant 2019YFE0196600, and the National Science Foundation under Grant CPS-1932413 and ECCS-2102312. This article was presented at the 2020 IEEE Wireless Communications and Networking Conference May 25–28, 2020. The associate editor coordinating the review of this article and approving it for publication was D. B. da Costa. (Corresponding author: Xiang Cheng.) Shijian Gao and Liuqing Yang are with the Department of Electrical and Computer Engineering, University of Minnesota, Twin Cities, Minneapolis, MN 55455 USA (e-mail: email@example.com; firstname.lastname@example.org).
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- Massive MIMO
- hybrid block diagonalization
- mutual information