在LTE-Advanced中繼架構下多重無線存取技術整合與換手效能評估

Multi-RAT support and performance evaluation for LTE-Advanced relay architecture

張朝欽(Chao-Chin Chang)

指導教授 ： 楊峻權

國立暨南國際大學/科技學院/資訊工程學系/碩士(2012年)

https://doi.org/10.6837/NCNU.2012.00238

摘要

LTE是由電信相關業者所組成的3GPP組織所制訂之無線通訊傳輸標準之一，具有與現有行動通訊網路(3G UMTS, 3.5G HSDPA…等)相容的特性，是目前4G標準中最被看好的一種廣域無線網路接取技術，在LTE架構之下，規範了行動用戶(UE)如何透過無線訊號與LTE核心網路(Evolved Packet Core, EPC)的基地台(E-UTRAN NodeB, eNB)連線並進行無線通訊；考量eNB無線訊號覆蓋範圍，在進階的LTE-Advanced環境，制訂了低耗電、低成本的中繼設備Relay Node(RN)加入，可讓訊號覆蓋範圍增加、解決訊號死角，使用者與基地台之間藉由RN做中繼轉傳，則可以得到較佳的傳輸品質。本文中所探討的多重無線存取技術(Multiple-Radio Access Technology, Multi-RAT)則是在原有的無線網路環境中支援額外的無線存取技術，使得該網路能讓不同系統的使用者存取到網路；由於不同的存取技術需要不同的基地台做支援，如此一來可能會增加電信業者的佈建成本，所以我們考慮讓RN不只支援一種無線存取技術，讓不同存取技術的使用者能透過RN來存取網路，而不需要為了每種存取技術佈建基地台，如此一來電信業者可以用較低成本，服務更多使用不同存取技術的使用者。本研究希望在不影響核心網路(Core Network, CN)的前提下，以UMTS為例進行多重無線存取技術的整合，將UMTS技術整合於RN上，讓UMTS的使用者能透過RN和UMTS核心網路交換資訊，在本論文研究中我們假設RN能支援UMTS基地台(NodeB, NB)的功能，提出了使用現有介面連接而成的架構，稱之為Architecture A；另外提出了使用All-IP方式連接的架構，稱之為Architecture B。我們針對這兩種架構的整合技術進行說明外，更進一步做了定性分析以及定量分析探討使用者在這些架構之下的換手效能，分析結果可以得知UE到RNC的路徑長短將會對效能造成最大的影響。未來研究中，我們將考慮探討RN若為Mobile RN的情況，此外還希望還能加入Local IP access (LIPA)的功能。

關鍵字

LTE-Advanced ； RN ； Multi-RAT ； 換手

並列摘要

Long Term Evolution (LTE) is one of 3GPP standards developed by 3GPP which is organized by telecommunication manufactories 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-AdvancedX and original LTE is a new entity called relay node (RN) introduced in LTE-Advanced. Comparing 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 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 flexibility services. However, the system architecture for Multi-RAT supporting is still under development. This thesis focuses on integrated architecture design by which RN can provide services for both UMTS UEs and LTE UEs. The proposed architectures can integrate 3G UMTS and 4G LTE-Advanced networks. Thus, the transition between 3G and 4G becomes more easily. The key motivation of proposed architectures is to improve system performance without modifying LTE-Advanced and UMTS core networks. The RN can serve UMTS UEs by integrating UMTS functionalities into RN. Two different architectures, namely Architecture A and Architecture B, are proposed in this manuscript. We assume that RN can support functionalties of UMTS Node B (NB) in both architectures. In Architecture A, existing interfaces are used to interconnect EPC and UMTS Core Network. On the other hand, IP-based intranet is used to interconnect between E-UTRAN and UMTS Core Networks in Architecture B. Comparisons and analytical results show that the distance between UMTS UE and RNC causes great impact on handover and transmission efficiencies.

並列關鍵字

LTE-Advanced ； RN ； Multi-RAT ； Handover

參考文獻

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