Low Complexity Beam Domain Detector with Group-Based Beam Extraction for XL-MIMO

In this paper, we propose a low complexity beamdomain detector with group-based beam extraction for extra-large-scale multi-input and multi-output (XL-MIMO) systems. We focus on detection in scenarios with strong user interference. To avoid the large-dimensional matrix inversion in the minimum mean square error (MMSE) detector caused by interfering users, we divide the users into different groups, and each group designs its beam domain detector with selected beams. Then, we propose a grouping method based on the statistical channel state information (CSI) to achieve effective grouping. The proposed detector performs a trade-off between the performance and complexity. Simulation results demonstrate that the proposed low-complexity method offers acceptable block error rate (BLER) performance while maintaining low complexity.