Coordinated resource allocation with vertical beamforming in 3D MIMO-OFDMA networks

This paper investigates coordinated resource allocation for 3-dimension (3D) antenna array systems in mul-ticell multiple-input multiple-output (MIMO) and orthogonal frequency division multiple-access (OFDMA) wireless networks. Cell-center user and cell-edge user specific downtilts are accordingly partitioned through dynamic vertical beamforming in the 3D MIMO-OFDM communication systems. Taking these user specific downtilts into consideration, the objective of our proposed coordinated resource allocation scheme is to maximize both the cell-edge users´ and cell-center users´ throughput, subject to per base-station (BS) power, cell-center user and cell-edge user specific downtilt constraints. To solve the coordinated resource allocation problem, resource blocks (RBs) are accordingly partitioned for cell-center users and cell-edge users, by referring to the fractional frequency reuse (FFR) scheme. Based on such RB partitioning, FFR-based dual decomposition method (FDDM) are proposed, where RB assignment, power allocation (RAPA) and downtilts adjustment are jointly optimized. Simulation results demonstrate the efficacy of our proposed coordinated resource allocation scheme.