A Proposal for Enhancing the Mobility Management in the Future 3GPP Architectures

Description Of Phases Of The Mobility Management

By carefully analysing the management of mobility, we can split the mobility management into three phases, namely handover information gathering, handover decision and handover execution. The handover information gathering phase gathers information (link monitoring, new incoming call…) and triggers the handover decision phase based on criteria. The handover decision phase selects one or more target network(s) taking into account user's preferences, operator's policies, and so on, and then triggers the handover execution phase. The handover execution phase asks the User Equipment (UE) to connect to the selected network(s). This phase encompasses a preparation phase (context transfer, QoS renegotiation, authentication …) before the execution phase itself consisting of a UE network interface attachment to the new network, a terminal location update, a data forwarding and a resource release on the previous network. Together, the three phases define a handover management chain as shown in Figure 1. These phases may be carried out separately by various entities comprising User Equipments and network nodes.

Figure 1.

The handover management chain

A question arises: which entity should manage the mobility of a user? His user equipment? One or several network nodes? Zdarsky and Schmitt (2004) proposed to shift the mobility management to the users. But if the viewpoint of the operator managing the networks differs from the viewpoint of a user, a conflict might appear between a user and the operator because the operator might want to choose a different target network from that chosen by a user. The debate whether the user-centric approach, i.e. the approach in which the users manage their mobility, or the network-centric approach, i.e. the approach in which the network operators manage the mobility of the users, is far from being over.