International audience

As energy concerns grow with the rise of energy-constrained devices, it becomes imperative to design an energy-efficient and adaptive multiple access (MA) scheme, supported with accurate energy efficiency (EE) evaluation. Non-orthogonal multiple access (NOMA) enhances EE, yet downlink NOMA faces challenges in terms of computational complexity and power demands of successive interference cancellation (SIC), problematic particularly for energy-limited devices. Existing studies overlook the additional SIC power consumption at NOMA receivers, thus overestimating EE, and giving misleading insights for real system design. Besides the need for more accurate EE evaluation, an adaptive MA approach based on this additional power consumption is required. This paper proposes a SIC-power-aware adaptive SDMA/cooperative NOMA system. An optimization problem is formulated by optimizing MA mode decision, BS beamforming, power allocation factors, and strong user relaying power, to maximize the system EE. We decouple the problem into SDMA/NOMA selection and power allocation sub-problems, solved via a modified semi-orthogonal user selection (SUS) algorithm, successive convex approximation (SCA), difference-of-convex (DC) programming, and semidefinite programming (SDP) approaches. Numerical evaluation confirms the efficiency of the proposed scheme, compared to the baseline schemes.

Non-orthogonal multiple access technique (NOMA) has appeared at the forefront as a viable solution capable of improving spectral and energy efficiency in fifth-generation (5G) and beyond-5G networks. This study aims at evaluating the benefits of adopting network slicing in cooperative NOMA-based systems with underlay Device-to-Device (D2D) communications. We formulate an optimization problem that maximizes the overall system's throughput while guaranteeing slices' technical requirements. We decouple the problem into two sub-problems: first, assigning the cellular users to resource blocks allocated to each NOMA group and then assigning D2D pairs to NOMA groups. A two-stage resource allocation solution by swapping-based matching theory is implemented. Numerical results show that the proposed scenario outperforms other ones in terms of the overall system's throughput and the number of admitted D2D pairs.