Interference Exploitation MU-MISO Precoding Under Per-Antenna Power Constraint

This paper studies the constructive interference (CI) precoding under per-antenna power constraint (PAPC) in the downlink of multi-user multiple-input single-output (MU-MISO) systems. The scenario of PAPC is more practical than that under sum power constraint (SPC) in actual systems. In this paper, we extend the mathematical precoding structure analysis of CI precoding under SPC to PAPC. By analyzing the formulated optimization problem with KKT conditions and generalized matrix inverse theory, we obtain the closed-form structure of the CI-PAPC precoder as a function of introduced variables and simplify the problem. Then, the primal-dual interior point method (IPM) is employed to solve this simplified problem more efficiently. Simulation results verify our mathematical derivations and show that the proposed method enjoys much lower complexity while maintaining the same communication performance, which promotes the practical implementation of CI precoding in realistic scenarios.