長期演進技術(LTE) 移動管理探討

Abstract

長期演進技術(Long Term Evolution;LTE) 的移動管理與第三代行動通訊系統有所不同。在長期演進技術中，行動管理實體(Mobility Management Entity;MME) 負責移動管理相關功能。而每一個行動管理實體與多個基站連接；而這些基站則組成數個追蹤區(TrackingArea;TA)；追蹤區列表則由數個追蹤區所組成。當手機移出所屬的追蹤區列表範圍外時，手機會向核心網路回報自己的位置；當核心網路欲與手機建立連線時，行動管理實體會命令追蹤區列表上所包含的基站向手機發出呼叫訊息。而行動管理實體可能會要求一個基站、一個追蹤區下轄基站或追蹤區列表下轄的所有基站同時發出呼叫。本文目的在探討及比較LTE 移動管理、基於距離的(distance-based) 管理及基於移動的(movement-based) 基礎管理。我們的研究發現，在某些交通流量或移動模式下，長期演進技術的移動管理會有較好的表現。

Mobility management in Long Term Evolution (LTE) is different from that of the third generation mobile telecom networks. In LTE, the Mobility Management Entity (MME) is responsible for the mobility management function. The MME is connected to a large number of evolved Node Bs (cells) that are grouped into the Tracking Areas (TAs). The TAs are further grouped into TA Lists (TALs). When a User Equipment (UE) moves out of the current TAL, it reports its new location to the MME. If the LTE network attempts to connect to the UE, the MME asks the cells in the TAL to page the UE. In LTE paging, the MME may sequentially page a cell, the TA of the cell, and/or TAL of the cell. This thesis investigates the performance of LTE paging, and compares LTE mobility management with the previously proposed movement-based and distance-based mobility management schemes. Our study indicates that under some traffic/mobility patterns, LTE yields the best performance.