Multimode Transmission in Network MIMO Downlink with Incomplete CSI

  • Nima Seifi1Email author,

    Affiliated with

    • Mats Viberg1,

      Affiliated with

      • Robert W. HeathJr.2,

        Affiliated with

        • Jun Zhang3 and

          Affiliated with

          • Mikael Coldrey4

            Affiliated with

            EURASIP Journal on Advances in Signal Processing20102011:743916

            DOI: 10.1155/2011/743916

            Received: 2 June 2010

            Accepted: 16 October 2010

            Published: 19 October 2010

            Abstract

            We consider a cooperative multicell MIMO (a.k.a network MIMO) downlink system with multiantenna base stations (BSs), which are connected to a central unit and communicate with multiantenna users. In such a network, obtaining perfect channel state information (CSI) of all users at the central unit to exploit opportunistic scheduling requires a substantial amount of feedback and backhaul signaling. We propose a scheduling algorithm based only on the knowledge of the average SNR at each user from all the cooperating BSs, denoted as incomplete CSI. Multimode transmission is applied that is able to adaptively adjust the number of data streams transmitted to each user. Utilizing the results of random matrix theory, an analytical framework is proposed to approximate the ergodic rate of each user with different number of data streams. Using these ergodic rates, a joint user and mode selection algorithm is proposed, where only the scheduled users need to feed back instantaneous CSI. Simulation results demonstrate that the developed analytical framework provides a good approximation for a practical number of antennas. While substantially reducing the feedback overhead, it is shown that the proposed scheduling algorithm performs closely to the opportunistic scheduling algorithm that requires instantaneous CSI feedback from all users.

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            Authors’ Affiliations

            (1)
            Department of Signals and Systems, Chalmers University of Technology
            (2)
            Wireless Networking and Communications Group (WNCG), Department of Electrical and Computer Engineering, The University of Texas at Austin
            (3)
            Deptartment of Electronic and Computer Engineering, Hong Kong University of Science and Technology, (HKUST)
            (4)
            Ericsson Research, Ericsson AB

            Copyright

            © Nima Seifi et al. 2011

            This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.