为了克服2G和3G移动通信网络位置管理方案的缺陷,4G长期演进(Long Term Evolution, LTE)采用了基于跟踪区列表(Tracking Area List, TAL)的位置管理方案。基于TAL的位置管理方案的性能取决于TAL分配方案。考虑到本地移动设备(User Equipment, UE)的活动区域相对固定,该文提出一种嵌入式马尔科夫链模型,用于分析本地UE的基于TAL的位置管理方案的信令开销。推导得到位置更新开销和寻呼开销的数学公式。利用这些公式,可搜索得到能使信令开销最低化的最佳TAL分配方案。
In order to tackle the defects of the Location Management (LM) scheme used in second generation (2G) and third generation (3G) mobile networks, forth generation (4G) network Long Term Evolution (LTE) uses a new LM scheme, which is called a Tracking Area List (TAL)-based LM scheme and the signaling cost of the TAL-based LM scheme is determined by the allocation of TALs. This paper develops a mathematical model of embedded Markov chain to analyze the signaling cost of the TAL-based scheme for a local User Equipment (UE) whose activity region is relatively fixed. Mathematical formulas for the LU cost and the paging cost are derived. With these formulas, an optimal TAL allocation strategy that can minimize the signaling cost can be found.