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This letter studies the resource allocation problem of sum rate maximization in wireless powered communication networks (WPCNs) with non-orthogonal multiple access (NOMA) that satisfy minimum data rate requirements per user. Firstly, we derive closed-form solutions for the time-splitting ratio and power allocation coefficients that maximize the approximated sum rate NOMA expression. Then, we use the solution of the approximated problem as the starting point for solving the original problem through Newton’s method. Simulation results show the effectiveness of the proposed approximation as well as the fast convergence of the optimal solution.

The next generations of mobile communications should deal with a set of new use cases, leading to a higher demand for spectral efficiency. Full‐duplex (FD) arises as a promising technology since it has the potential to double the system capacity without additional spectrum. However, FD networks are hindered by self‐interference (SI) and co‐channel interference caused by the reuse of frequency resources. Therefore, radio resource allocation (RRA) in FD networks by means of user pairing, frequency assignment, and power allocation are of utmost importance in order to improve spectral/energy efficiency and ensure quality of service (QoS). Although previous works investigated RRA to improve spectral efficiency, the fundamental question of where adaptive power allocation should be employed in the uplink and/or downlink of FD networks in a cost‐effective way remains unanswered. This article addresses this question in the context of total data rate maximization with QoS constraints where we propose four optimization problems using different power allocation strategies. The branch and bound method is employed to optimally solve the four formulated problems, which were used as upper bound solutions for benchmarking purposes. Moreover, we propose a low computational complexity solution able to adaptively switch the power allocation strategy depending on the scenario. Detailed system‐level simulations indicate that the best node to employ adaptive power allocation (mobile terminal or base station) depends on the cell radius and SI level. Also, our results show that, compared to existing solutions, the proposed low‐complexity is a great and intelligent strategy in terms of system performance and computational complexity considering both perfect and imperfect channel state information. We propose four optimization problems using different power allocation strategies to solve the total data rate maximization problem with minimum rate constraints in full‐duplex systems. Motivated by the high computational complexity to obtain the optimal solutions of the investigated problems, we propose a heuristic solution with lower computational complexity. The proposed solution presents good performance in terms of outage rate and spectral efficiency when the performance/complexity trade‐off is assessed.

Despite the advent of fifth‐generation mobile networks in the next years, the Long‐Term Evolution system still have an important role in the mobile communication scenario. Moreover, the development of solutions that fulfill the demand of new multimedia applications as well as provide an efficient use of the energy resources is one of the drivers of future networks. Therefore, in this article, we deal with the total energy efficiency maximization problem subject to minimum satisfaction constraints per service and quality of service in the uplink of Long‐Term Evolution using single‐carrier frequency‐division multiple access. Although the formulated problem is a nonlinear combinatorial optimization problem, we obtain the optimal solution through algebraic manipulations and by using an iterative method. Motivated by the high computational complexity to obtain the optimal solution, we propose a heuristic solution with lower computational complexity. Realistic system‐level simulations indicate that the proposed solution presents good performance regarding both outage rate and energy efficiency. We propose the energy efficiency maximization problem subject to minimum satisfaction constraints per service and Quality‐of‐Service (QoS) for uplink of Single Carrier ‐ Frequency Division Multiple Access (AS‐FDMA) system. We obtain the optimal solution of a non‐linear combinatorial optimization problem through algebraic manipulations and by using an iterative method. We propose a low complexity heuristic solution that presents good performance regarding both outage rate and energy efficiency compared to the optimal solution and other solutions selected form the recent literature.