The focus of this paper is targeted towards multi-cell 5G networks composed of High Power Node (HPNs) and of simplified Low Power Node (LPNs) co-existing in the same operating area and sharing the scare radio resources. Consequently, high emphasis is given to Inter-Cell Interference Coordination (ICIC) based on multi-resource management techniques that take into account user association to cells. Beside user association, this paper takes also power control and scheduling into consideration. This complex problem is remained largely unsolved, mainly due to its non- convex nature, which makes the global optimal solution difficult to obtain. We address the user association challenge according to the two broadly adopted approaches in wireless networks: the network-centric approach where user association is allocated efficiently in a centralized fashion; and the user-centric approach where distributed allocation is used for reduced complexity. The scheduling and ICIC power control are solved in a centralized fashion, in order to reach an optimal solution of the joint optimization problem.