多重無線接取技術連線管理及其應用之研究

Abstract

智慧型行動裝置的普及帶動了行動資料流量快速成長。大多數的智慧型行動裝置都配備了多重無線網路介面，如高速封包存取(HSPA)、長期演進技術(LTE)、與Wi-Fi。因此，多重網路的整合對滿足流量卸載與行動網路使用者之資料傳輸服務品質需求來說，是一個可行的解決方案。第三代合作夥伴計劃與國際網路工程研究團隊提出了網路協定來支援蜂巢式連線與Wi-Fi連線間的使用者裝置(UE)移動性。除了移動性議題以外，當不同無線網路(如長期演進技術與Wi-Fi)的覆蓋範圍重疊時，使用多重網路連線來同時傳送不同的服務資料(如頻寬聚合的方式)可幫助平衡網路負載。在本研究中，我們探討多重無線接取技術連線管理及其應用。 在多重無線接取技術(如長期演進技術與Wi-Fi)整合網路架構中，我們提出了一個多重無線接取技術整合機制來處理在LTE與Wi-Fi無線網路間的選擇與切換。我們分別於使用者裝置與核心網路端提出了一個多重無線接取技術連接系統(MRA)與一個多重連線管理系統(MCM)，來處理多重無線接取技術整合機制。我們將此機制應用於高鐵上的通訊以改進其效能。研究結果顯示透過多重無線接取技術機制可有效改善高鐵上的連線可用性。 我們將多重無線接取技術上頻寬聚合的概念延伸到一個新興的網路架構，稱為軟體定義網路(SDN)。本研究所提之基於軟體定義網路之多重無線接取技術網路架構讓網路具備可程式化、可動態管理、與適應性強等特性。研究結果顯示我們所提之機制可在些微降低吞吐量的情況下大量減少網路回應時間。 為了達到多重無線接取技術網路的負載平衡，我們在軟體定義網路環境的長期演進技術與Wi-Fi整合式網路架構中實作了接取網路搜尋與選擇功能。研究結果顯示在網路流量不平衡的狀況下，此作法可比前期研究更能有效率地減少Wi-Fi接取點的電力消耗。

The population of smart mobile devices drives the mobile traffic growth rapidly. Most smart mobile devices are equipped with multiple radio network interfaces, such as High Speed Packet Access (HSPA), Long Term Evolution (LTE), and Wi-Fi. Therefore, integration of multiple networks is a viable solution to fulfill traffic offloading and the Quality-of-Service (QoS) requirement of data usage for mobile users. The 3GPP and the IETF proposed network protocols to support user equipment (UE) mobility between the cellular connections and the Wi-Fi connections. Other than mobility issues, when the coverages of various wireless networks (e.g., LTE and Wi-Fi) are overlapped, using multiple network connections to transfer different services simultaneously (e.g., bandwidth aggregation) helps to balance the network load. In this dissertation, we study the multi-RAT connection management and its applications. In the multi-RAT (e.g., LTE and Wi-Fi) integrated network architecture, we propose a multi-RAT mechanism to handle the radio network selection and switching between LTE and Wi-Fi networks. A multi-RAT adaptor (MRA) and a multi-connection manager (MCM) are proposed for the UE and the core network, respectively, to handle the multi-RAT mechanism. As an application, we use this mechanism to enhance the performance of the high speed rail (HSR) communications. Our study indicates that the connection availability of HSR can be effectively improved through the multi-RAT mechanism. We extend the concept of bandwidth aggregation on multi-RAT to an emerging proposed network architecture called software-defined networking (SDN). The proposed SDN-based multi-RAT network architecture makes the network more programmable, dynamically manageable and adaptable. Our study indicates that our mechanism can significantly reduce the response time with slight throughput degradation. For load balancing of the heterogeneous radio networks, we implement the Access Network Discovery and Selection Function (ANDSF) mechanism for the LTE and Wi-Fi integrated network in the SDN environment. Our study indicates that for unbalanced traffic, this approach can efficiently reduce power consumption of Wi-Fi AP than the previous approaches.