Channel (broadcasting)

Mathematics

Transmitter power output

Evolutionary biology

Biology

Mathematical optimization

Quadratic equation

Regular polygon

Convex optimization

Optimization problem

Telecommunications link

Function (biology)

Convex function

Minification

Linear matrix inequality

Geometry

Computer science

Transmitter

Quadratic programming

Quadratically constrained quadratic program

Telecommunications

Intelligent reflecting surface (IRS) has recently been recognized as a promising technology to enhance the energy and spectrum efficiency of wireless networks by controlling the wireless medium with the configurable electromagnetic materials. In this paper, we consider the downlink transmit power minimization problem for a IRS- empowered non-orthogonal multiple access (NOMA) network by jointly optimizing the transmit beamformers at the BS and the phase-shift matrix at the IRS. However, this problem turns out to be a highly intractable non-convex bi- quadratic programming problem, for which an alternative minimization framework is proposed via solving the non- convex quadratic programs alternatively. We further develop a novel difference-of-convex (DC) programming algorithm to solve the resulting non-convex quadratic programs efficiently by lifting the quadratic programs into rank-one constrained matrix optimization problems, followed by representing the non-convex rank function as a DC function. Simulation results demonstrate the performance gains of the proposed method.

Intelligent Reflecting Surface for Downlink Non-Orthogonal Multiple Access Networks