LTE家用基地台網路可移動訊務卸載技術

Traffic Offloading in LTE HeNB Networks with Mobility

在LTE網路中，為了減輕核心網路的負擔，訊務卸載（Traffic offloading）技術即為此而生。其中有一部份實作在家用基地台（Home eNodeB，HeNB）子系統上的訊務卸載技術將部分的流量以HeNB子系統內的區域閘道器（Local GateWay，L-GW）做為卸載點（Break-out point）讓封包不進入核心網路，由L-GW為使用者裝置（User Equipment，UE）轉送封包。然而此種訊務卸載技術卻有著不具備移動性的缺陷，導致使用者的服務若被卸載，將不允許離開卸載點的服務範圍，否則服務將被中斷。本論文提出一套在區域HeNB網路（Local HeNB Network，LHN）上可移動的訊務卸載技術。利用過濾封包的方式列管LHN內所有的服務及UE，由LHN的L-GW（Local GateWay）以不修改服務內容為前提，對LHN內的封包進行路由，以達到可移動之訊務卸載功能。

The traffic in mobile communication networks will grow up year after year. The 3GPP organization proposed a series of traffic offloading methods in Long Term Evolution-Advanced system, which tried to offload part of traffic from core networks to the Internet. There are some traffic offloading methods on Home eNodeB (HeNB) subsystem, Local IP Access (LIPA), and Selected IP Traffic Offload at Local Network (SIPTO@LN), providing communication ability with other objects by HeNB without access the core network. But the traffic offloading methods in HeNB subsystem have no mobility. We propose two methods, which have mobility more than others. The first method, LATO, provides LIPA function with handover ability. The second method, GATO, provides SIPTO function with hand-out ability.