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)

    Abstract

    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
    Pages4118-4122
    Number of pages5
    DOIs
    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

    Other

    OtherIEEE International Conference on Communications, ICC 2008
    Country/TerritoryChina
    CityBeijing
    Period08/5/1908/5/23

    ASJC Scopus subject areas

    • Computer Networks and Communications
    • Electrical and Electronic Engineering

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