Design method of multiuser MIMO system using large scale transmit array with low computational cost based on subarray division

Abstract

This paper proposes an efficient design method of multiuser multiple input multiple output (MIMO) downlink system assuming use of a large array antenna in transmitter side. To reduce the heavy computational load required for transmit weight design, the large antenna is first divided into several subarrays, and block diagonalization method is applied to each of them. Then subarrays are again synthesized to a large array with the original size based on the concept of the maximum ratio combining (MRC), where two kinds of strategies, the transmitter first design and the receiver first approach are considered. Computer simulations show that the performance is degraded from the original method, but it can be achieved with significantly low computations so that it is utilizable even when the conventional block diagonalization is computationally impractical.