New beamforming schemes with optimum receive combining for multiuser MIMO systems

Sang Rim Lee, Seokhwan Park, Sung Hyun Moon, Inkyu Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)


In this paper, we present a new beamforming scheme for a downlink of multiuser multiple-input multiple-output (MIMO) communication systems. Recently, a block-diagonalization (BD) algorithm has been proposed for the multiuser MIMO downlink where both a base station and each user have multiple antennas. However, the BD algorithm is not efficient when the number of supported streams per user is smaller than that of receive antennas. Since the BD method utilizes the nullspace based on the channel matrix without considering the receive combining, the degree of freedom for beamforming cannot be fully exploited at the transmitter. In this paper, we optimize the receive beamforming vector under a zero forcing (ZF) constraint, where all inter-user interference is driven to zero. We propose an efficient algorithm to find the optimum receive vector by an iterative procedure. The proposed algorithm requires two phase values feedforward information for the receive combining vector. Also, we present another algorithm which needs only one phase value by using a decomposition of the complex general unitary matrix. Simulation results show that the proposed beamforming scheme outperforms the conventional BD algorithm in terms of error probability and obtains the diversity enhancement by utilizing the degree of freedom at the base station.

Original languageEnglish
Title of host publicationICC 2008 - IEEE International Conference on Communications, Proceedings
Number of pages5
Publication statusPublished - 2008
EventIEEE International Conference on Communications, ICC 2008 - Beijing, China
Duration: 2008 May 192008 May 23

Publication series

NameIEEE International Conference on Communications
ISSN (Print)0536-1486


OtherIEEE International Conference on Communications, ICC 2008

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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