長期演進技術升級版(LTE-A)為目前競爭4G的標準之一，長期演進技術(LTE)和長期演進技術升級版同樣為3GPP組織所發展的標準，並且LTE和LTE-A同樣可以向下相容3GPP先前提出的標準，如通用行動通訊系統(UMTS)，通用封包無線服務(GPRS)，全球行動通訊系統(GSM)等，為了使無線資源的使用度增加，電信供應商可以再一個給定的訊號範圍內用一台無線設備同時支援多重無線存取技術，而且能完整的攜帶使用者所用的不同無線服務，如果LTE-A的基地台能利用虛擬化系統同時支援包括UMTS，WiFi，WiMAX，則LTE-A系統就能提供更有彈性的網路服務，然而還沒有適合多重無線存取技術(Multi-RAT)虛擬化系統架構，所以本篇文章重點在於設計讓DeNB能同時提供UMTS UEs和LTE USs的虛擬化架構，在此篇文章中提出了兩種架構分別為Arch_A和Arch_B，如多重無線存取技術虛擬化架構圖所示，我們提出的技術能結合3G UMTS和4G LTE-A兩種無線網路，因此可讓設備在3G和4G移動變得更容易。
Long Term Evolution (LTE) is one of 3GPP standards developed by 3GPP which is organized by telecommunication manufacturers and operators. It is backward compatible with 3G/UMTS cellular systems and competing access network technologies in 4G wireless networks with WiMAX. The major difference between 3GPP Release 10 LTE-Advanced and the original LTE is a new entity called relay node (RN) introduced in LTE-Advanced. Compared to a base station, RN is a low-power and low-cost device. An Evolved Node B (eNB) can extend its serving coverage and provide a better quality of radio signal to users by using RN. Multiple radio access technologies (Multi-RAT) mean that a base station is composed of more than one radio access technology. If RN can support Multi-RAT including UMTS, IEEE 802.11 and 802.16, the LTE-Advanced network can further provide more flexible services. Our previous project had proposed a basic Multi-RAT RN structure. However, the system architecture for Multi-RAT supporting when deploying RN inside high speed railway (HSR), this scenario is also an important mobility problem when RN movement. When RN handover to next DeNB due to HSR movement, the Multi-RAT Mobile RN (as Multi-RAT MRN) should re-connect to the new DeNB and manage the current different RAT end-to-end connection for service UEs and their corresponding Core Network devices. Furthermore, there are some roaming users (from different operators) in the railway carriage. To support these users within the same MRN devices is an efficient solution for Multi-Operator, the Virtualization Multi-RAT functionality of MRN is also proposed in this project. This project focuses on integrated architecture design by which MRN can provide services for the UMTS UEs, LTE UEs and roaming users. To design an appropriate architecture when RN deployment happens in a HSR environment, this project investigates and analyzes possible connection management and resource allocation scheme in E-UTRAN and EPC architectures with associated interfacing for the case of MRN supporting both LTE-UE and UMTS-UE under the same operator or different operators.