Energy Efficiency Maximization for Discrete Activation based NOMA-assisted Pinching-Antenna Systems

Pinching-antenna systems (PASS) have recently attracted significant attention as a promising architecture for flexible and reconfigurable wireless communications. Despite notable advancements, research on energy efficiency (EE) maximization for PASS is limited as existing studies mainly focus on transmit power minimization or utilizing a simple power consumption model. This paper evaluates the impact of pinching antenna (PA) activation power on EE maximization in a downlink NOMA-assisted PASS by jointly optimizing PA activation and user power allocation under quality-of-service and transmit power constraints. To tackle the resulting mixed-integer nonlinear programming problem, we develop a two-layer iterative algorithm, where the outer layer performs matching-based PA selection and the inner layer computes a closed-form optimal power allocation solution. Numerical results demonstrate that the proposed solution achieves substantial EE gains over conventional fixed antennas systems and the considered benchmark schemes, approaches the exhaustive-search upper bound with significantly reduced complexity, while exhibiting fast convergence. It also demonstrates the significance of accounting for PA activation power in EE maximization problem.

Optimal Power Allocation in Uplink NOMA with Simultaneous Cache-Enabled D2D Communications

Non-orthogonal multiple access (NOMA) is widely viewed as a potential candidate for providing enhanced multiple access in future mobile networks by eliminating the orthogonal distribution of radio resources amongst the users. Nevertheless, the performance of NOMA can be significantly improved by combining it with other sophisticated technologies such as wireless data caching and device-to-device (D2D) communications. In this letter, we propose a novel cellular system model which integrates uplink NOMA with cache based device-to-device (D2D) communications. The proposed system would enable a cellular user to upload data file to base station while simultaneously exchanging useful cache content with another nearby user. We maximize the system sum rate by deriving closed form solutions for optimal power allocation. Simulation results demonstrate the superior performance of our proposed model over other potential combinations of uplink NOMA and D2D communications.