Two-Timescale Design for Downlink Multiuser Transmission with Dynamic Metasurface Antennas
For wireless communication systems, this work addresses the challenge of reducing energy and hardware costs in massive MIMO by introducing a practical two-timescale DMA design that improves spectral efficiency.
This paper proposes a two-timescale design for downlink multiuser transmission using dynamic metasurface antennas (DMAs), balancing pilot overhead, complexity, and spectral efficiency. The DMA coefficients are configured based on statistical CSI at the frame level, outperforming stochastic successive convex approximation, while the digital precoder is updated per slot using instantaneous CSI. Performance evaluations show the design is attractive for future wireless networks.
Dynamic metasurface antennas (DMAs) promise to relieve massive multiple-input multiple-output architectures from their high energy consumption and hardware costs. This paper proposes a two-timescale design for downlink multiuser transmission via DMAs, a design that balances pilot overhead, complexity, and spectral efficiency. At the onset of each frame, the DMA coefficients are configured based only on statistical channel-state information (CSI), a process for which the paper introduces an optimization framework that is shown to outperform the widely used stochastic successive convex approximation method. Then, within each frame, the digital precoder is updated at each slot, based on the optimized DMA coefficients and the effective lower-dimensional instantaneous CSI. The weighted minimum mean-squared error method is applied for this short-term optimization and, for the special case of single-user transmission, a closed-form solution for the digital precoder is provided. Performance evaluations demonstrate that the proposed two-timescale design can be an attractive ingredient for future wireless networks.