下一代行動通信系統即時數據資料存取之研究

Abstract

發展一個全IP網路是下一代行動通信系統主要的目標，全IP行動通信系統以分封方式建立通訊連線，提供即時性的多媒體服務。寬頻劃碼多重接取(WCDMA) 系統是目前世界上最廣泛使用的第三代行動通信標準，為在下一代行動通信系統中支援即時性分封多媒體服務，寬頻劃碼多重接取系統必須具備高效率的無線資源管理，以提供即時性服務品質的保證。在寬頻劃碼多重接取系統中，基地站的功率和展頻碼是最重要的無線資源，因為無線資源是有限的，因此在本論文□，我們將對即時性數據進接時，提出多種無線資源的管理策略，以降低基地站細胞涵蓋區內功率的消耗，同時使展頻碼的使用更有效率。 為解決上述問題，首先我們提出一個管理無線資源的平台。利用此管理平台我們提出RTGS演算法，以排序方式提供即時性封包服的務品質保證。其次我們提出RTBS演算法，利用EDF機制對即時性封包先進行可排序分析，以降低功率的消耗。透過利用展頻碼動態分配的原理，我們發展RTCS演算法，RTCS演算法可以增加即時性封包可排序的機率，同時提昇無線資源的使用效率。再者，我們提出RTIS演算法，在多媒體的環境下可以有效率地同時處理即時性和非即時性封包。 隨著新的進接技術的發展，寬頻劃碼多重接取系統利用高速下鏈分封進接技術 (HSDPA)支援即時性多媒體服務。在本論文中我們發展新的高速下鏈分封進接技術資源管理策略，當處理即時性封包時，對於高速下鏈分封進接技術使用的資源 - 高速下鏈共享通道碼 (HS-DSCH) 進行有效率分配。其次利用發展新的高速下鏈分封進接技術資源管理策略，我們提出RTCA演算法，此演算法是藉由允諾控制和排序方式，提供即時性封包在速率和延遲的服務品質保證。此外我們改進RTCA演算法，提出RTSC演算法，利用較早到達期限優先處理 (EDF) 機制增加即時性封包可排序的機率，同時提昇高速下鏈共享通道碼的使用效率。 寬頻劃碼多重接取系統利用展頻碼的配置提供各種不同應用服務高速率頻寬和可變的傳輸速率，寬頻劃碼多重接取系統展頻碼是運用正交可變展頻因子 (OVSF) 技術把行動用戶的資料展頻成3.84 Mcps後由空中介面傳輸。本論文提出FDCA 演算法，可以根據行動用戶速率的要求，快速分配展頻碼供行動用戶使用。本演算法首先估算欲被指派使用展頻碼的成本，展頻碼成本計算方式是考慮其後代展頻碼被佔用的情形，利用FDCA 演算法可以在所有符合用戶速率要求的展頻碼中，快速找到一個成本最小的展頻碼供行動用戶使用。

The development of an all IP-based network is the future for the next generation mobile system. The all IP-based network enables Packet-switched connections to offer real-time multimedia services. The Wideband Code Division Multiple Access (WCDMA) is the most popular 3rd Generation (3G) mobile standards. To support packet multimedia services, the WCDMA system must provide efficient radio management for real-time services quality-of-service (QoS) provisioning. In a WCDMA system, the base station power and channelization codes are two most important radio resources. In this dissertation, we propose resource management polices for real-time data access to decrease mobile users' power consumption within a cell, and to improve channelization codes utilization. First, the concept of the management framework is introduced to solve above problems. Based on the management framework, we present the Real-Time Generic Scheduling (RTGS) algorithm to schedule real-time packet traffic, which guarantee the real-time QoS. Moreover, we design the Real-Time Bandwidth Scheduling (RTBS). The RTBS algorithm implements the early-deadline-first (EDF) scheme to do the schedulability analysis. Applying the dynamic code assignment (DCA) scheme, the Real-Time Code Scheduling (RTCS) algorithm is used to increase the probability of schedulable sessions and improve the radio resource utilization. Furthermore, we also propose the Real-Time Imprecise Scheduling (RTIS) to serve mixed real-time and non-real-time packets efficiently in a multimedia environment. With the improvement in new access technology, the High Speed Downlink Packet Access (HSDPA) is used to support real-time multimedia services in next generation mobile system. We devise new High Speed-Downlink Shared Channel (HS-DSCH) code management schemes that efficiently assign the HSDPA resource - HS-DSCH codes for real-time packet traffic. Based the code management schemes, the Real-Time Code Allocation (RTCA) employs the admission control and the packet scheduling schemes to guarantee the bit rates and delay attributes for the real-time data session QoS requirement. Extending from the RTCA algorithm, the Real-Time Sharing Code (RTSC) algorithm applies the EDF scheme to do the schedulability analysis, increasing the schedulable probability for the real-time sessions and, thus, improving the utilization of HS-DSCH codes. The WCDMA system supports high-rate bandwidth and variable-rate transmission for various applications according to the channelization code allocation. The channelization codes spread information for each mobile user base on the orthogonal variable spreading factor (OVSF) technique. We present a Fast Dynamic Code Assignment (FDCA) algorithm to assign a channelization code for a mobile user request. We evaluate a cost for an OVSF-code allocation. The cost is obtained by calculating the number of available and occupied descendant codes of the code. The FDCA algorithm can assign a suitable code for the bit rate requirement and, in addition, the cost obtained by the evaluation scheme is small.