New Beamforming Designs for Joint Spatial Division and Multiplexing in Large-Scale MISO Multi-User Systems

Younghyun Jeon, Changick Song, Sang Rim Lee, Seungjoo Maeng, Jaehoon Jung, Inkyu Lee

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

In this paper, we study a joint spatial division multiplexing (JSDM) beamforming scheme, which enables large-scale spatial multiplexing gains for massive multi-input multi-output downlink systems. In contrast to the conventional JSDM, which employs a block diagonalization method as a pre-beamformer, we aim to maximize sum-rate by applying minimum-mean-squared error (MMSE) approaches when designing a pre-beamformer and a multi-user precoder sequentially. First, to suppress inter-group interference, we design the pre-beamformer, which minimizes an upper bound of the sum mean-squared-error in the large-scale array regime. Then, to mitigate same-group interference, we present the multi-user precoder based on the weighted MMSE (WMMSE) optimization method, which requires the same channel state information overhead as the conventional JSDM. Also, in order to reduce the computational complexity, we compute deterministic equivalents of the WMMSE beamforming parameters to generate the beamformers by employing asymptotic results of large system analysis. Through simulation results, we confirm that the proposed two-step beamforming methods bring substantial performance gains in terms of sum-rate over the conventional JSDM schemes especially in a low and medium signal-to-noise ratio regime with comparable complexity.

Original languageEnglish
Article number7880687
Pages (from-to)3029-3041
Number of pages13
JournalIEEE Transactions on Wireless Communications
Volume16
Issue number5
DOIs
Publication statusPublished - 2017 May 1

Keywords

  • Massive MIMO systems
  • two-stage beamforming
  • weighted MMSE

ASJC Scopus subject areas

  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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