# Mobility Management Scheme with Mobility Prediction in Wireless Communication Networks
## 1 Introduction  
In a wireless communication network, the location of user equipment (UE) must be kept to successfully connect an incoming call to the UE. Mobility management in wireless communication networks consists of two important processes: location registration and paging [1, 2, 3]. To provide successful mobility management services, the wireless communication network consists of non-overlapped tracking area (TA). Several TAs constitute a TA list (TAL). When a UE moves to another TA whose TAL is different from the stored TAL in the mobility management entity (MME) database, registration process is performed. When an incoming call to a UE occurs, a paging procedure is performed to connect it to the UE. MME sends paging message to all base stations in a TA whose TAL is stored in MME. In general, there exists a trade-off relation to treat the signaling cost between the location registration and paging [2, 4, 5, 6, 7]. So far, many studies have been conducted to reduce the total signaling cost for registration and paging [4, 8, 9, 10, 11, 12, 13].  
Various results on mobility management schemes to minimize the total signaling cost have been proposed, such as zone-based registration [14, 15, 16], movement-based registration [5, 17], distance-based registration [18, 19, 20, 21], TAL-based registration [11, 22], and so on. Among them, [PERSON] et al. [10] have proposed a registration scheme with flexible TAL forming to reduce total signaling cost for automotive users in LTE-advanced communication network using information of UE's moving direction. In this scheme, based on theknown geographical area of the trace, its map, and the UE's moving statistics, the UE's moving direction can be predicted. Furthermore, they proposed to form TALs not only as rings of TAs, but also as sectors of different sizes that depend on the most probable movement angle. Through a simulation analysis, the performance of the proposed scheme was compared with the movement-based and distance-based registration schemes. However, their study did not present user's accurate mobility and corresponding analytical model to evaluate its performance and show its superiority. Note that the improved TAL-based algorithm proposed by [PERSON] and [PERSON] [11] did not consider the UE's mobility prediction.  
In this study, we present a registration scheme considering mobility prediction and corresponding flexible TAL forming. In this scheme, based on mobility prediction and corresponding TAL forms, a new TAL was constructed such that the registration cost can be minimized. We also newly present a semi-Markov process model for the flexible registration scheme with TAL forming. In addition, a simulation study was performed using RAPTOR [23] to validate the analytical results. Its performance was compared with those of distance-based [20,21] and TAL-based registration schemes [11,22] previously proposed in LTE networks.  
This paper is composed of as follows: Section 2 introduces the registration scheme with flexible TAL forming based on the prediction of UE's moving direction, where two different environments are considered: urban and rural. In Section 3, the signaling cost of the proposed scheme is analyzed using the semi-Markov process model. In Section 4, the simulation model is explained. Numerical results on the performance of the proposed scheme are presented in Section 5. Finally, Section 6 provides conclusions of this paper.