Sum Rate Maximization of DMA-Based Multiuser MIMO Systems

A novel antenna technology referred to as dynamic metasurface antennas (DMA) that employs reconfigurable metamaterials as its radiating/receiving elements has emerged as a potential alternative to traditional antennas. It specifically helps to simplify the hardware complexities of transceiver structures by reducing the number of radio frequency (RF) chains, thus lowering the operational cost of multiple-input multiple-output (MIMO) systems. To assess its usefulness, this study analyzes the capacity characterization of different DMA-based multiuser MIMO systems by considering uplink and downlink communications when DMA is deployed at the base station or the users. In each case, we formulate a capacity maximization problem. Further, using either reduced minimum mean square error or iterative waterfilling techniques, we propose efficient algorithms to optimize transmit precoders and DMA configurable weights alternately. The solution for each optimizable variable is designed to attain fast convergence that ensures the overall low complexity of the proposed scheme. The simulation results demonstrate the effectiveness of the proposed algorithms in achieving performance comparable to conventional MIMO while significantly reducing the number of RF chains.