Completion Time Minimization Oriented Cross-Layer Design in Multiuser Communication Networks

As a pivotal technology for enabling future sixth-generation (6G) networks, the integration of cross-layer design in beamforming and multiuser scheduling introduces significant challenges in multiuser systems with minimum rate requirements. In this letter, we address the problem of minimizing user completion time with a general form. To circumvent the issue of non-causality, we introduce a dual-timescale approach, considering a two-stage design methodology that encompasses joint optimization of scheduling and power allocation at the long-term level and beamforming design from the short-term perspective. Due to the complexity of the long-term design, we employ a relaxation technique that preserves optimality, ultimately achieving a stationary solution through a penalty convex-concave procedure. Numerical results demonstrate that the proposed method substantially outperforms existing baselines and approaches the lower bound established by a non-causal method.