Robust energy-efficient precoding optimization for dual-polarized multiuser MIMO downlink

In this paper, we investigate the robust fairness-based energy efficiency (EE) optimization of the dual-polarized multiuser multiple-input multiple-output (MIMO) downlink. Exploiting the special dual-polarized antenna structure, the polarization-based subgrouping technique is adopted which enjoys low implementation complexity, low feedback overhead and good performance. Based on this, the proposed robust fairness-based EE precoding design aims at maximizing the minimum EE, i.e., the worst-case EE, achieved among all users with the norm bounded channel errors. Further, the formulated nonconvex EE optimization problem is transformed into a series of standard semidefinite programming (SDP) problems, which can be effectively solved by the convex optimization techinique. Simulation results demonstrate the robust EE performance advantages of the proposed polarization-based subgrouping precoding scheme.