Localized Mobility Management for 5G Ultra Dense Network

It is commonly agreed that the ultra dense network (UDN) will be a key technology to face extremely dense traffic and high-speed data rate in the fifth-generation (5G) network. However, due to its new characteristics such as high dense small cells, fast and flexible deployment of small cell access points, and flexible backhaul connectivity, how to enable mobility support is becoming a great challenge. In this paper, based on newly proposed network architectures for UDN, we present two efficient localized mobility management schemes considering small cell deployments and backhaul topology. The first one centralizes mobility management control from small cell access points into a local access server (LAS) closing to radio access network. Another one allows individual small cell access points to handle mobility events, but still requires the LAS to act as mobility anchor. According to the performance evaluation results of the proposed schemes by using numerical analysis and simulation, respectively, including average handover signaling cost, average packet delivery cost, average handover latency, and average signaling load to the core network, the localized mobility management with centralized control scheme has the best performance, and the other one has less handover signaling cost, but higher handover latency than the third-generation partnership project (3GPP) scheme.