UL/DL decoupled user association in dynamic TDD small cell networks

User association is a key factor that affects the performance of wireless cellular small cell networks. In this paper, the problem of decoupled uplink (UL) and downlink (DL) in time division duplexing (TDD)-based small cell networks is studied. In particular, a dynamic user association scheme is proposed to dynamically balance the UL and DL loads in different small cell base stations (SCBSs). Using the proposed scheme, users can connect to different SCBSs in the UL and the DL depending on the traffic load and signal strength. The proposed user association scheme allows for different UL and DL cell coverage areas that shrink and expand depending on traffic load in both directions. Simulations results show that the proposed scheme achieves significant gains in terms of packet throughput, cell-edge throughput and service delay as compared to static and dynamic duplexing schemes with coupled UL/DL user association.