Journal of Communications and Networks, vol. 11, no. 3, pp. 279-286, June 2009.
This paper proposes an adaptive mode switching method between two important strategies in multiple antenna cellular networks: a single user mode and a multi-user mode (broadcast channel). Such a mode switching could be employed in each cell, or in a coordinated setting across cells to increase system throughput. If full channel state information is available at each base-station, it is known that a multi-user precoding would outperform single user precoding. In the absence of such side information, it is unclear what the capacity achieving method is and thus lacking a benchmark which of the myriad possible methods performs best given a system configuration. We compare popular strategies termed single and multi-user transmission in this paper, and find that neither strategy dominates the other. There is instead a transition point between the two. This paper then determines this switching point both analytically and numerically for the case of a multiple antenna cellular downlink with transmit side correlation between the antennas.
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