Transceiver Design for Optimizing the Energy Efficiency in Multiuser MIMO Channels

This letter studies the transceiver design for optimizing the energy efficiency (EE) in a secure multiple-user multiple-input-multiple-output wireless system. Such a design problem is a highly-nonlinear program whose optimal solution is hardly found. To address its suboptimal solution, an interference alignment technique is first employed to cancel information leakage and interference, and, thus, the design problem is recast into a computationally tractable concave-convex fractional program. Then, we reformulate the fractional program into convex optimization by adopting the Dinkelbach method. Furthermore, by invoking the dual problem, a semiclosed-form solution is derived for an efficient iterative algorithm. The simulation results demonstrate the superior EE performance of the proposed method over the conventional methods, especially in the high transmit power regime.