Modeling of tracking area list-based location update scheme in Long Term Evolution

Long Term Evolution uses a new location update (LU) scheme, called a tracking area list (TAL)-based scheme, to overcome the defects of the LU scheme used in 2G and 3G cellular networks. Under the TAL-based LU scheme, each time a user equipment (UE) performs an LU, it is allocated a group of tracking areas, referred to as a TAL, within which the UE can move freely without any LU. The UE performs an LU when moving out of the TAL. The performance of the TAL-based LU scheme depends on the allocated TAL. In this paper we develop a mathematical model to analyze the signaling overhead of the TAL-based LU scheme for local UEs whose mobility exhibits strong regularity. We derive formulas for the LU cost and the paging cost of a TAL allocation strategy. With these formulas we can find an optimal TAL allocation strategy to minimize the signaling cost of the TAL-based LU scheme.