陳健輝臺灣大學：資訊工程學研究所曾義憲Tseng, Yi-HsienYi-HsienTseng2007-11-262018-07-052007-11-262018-07-052007http://ntur.lib.ntu.edu.tw//handle/246246/53705近來無線通訊技術的發展(例如:超寬頻)已經使得人們有機會在家中享受高品質的無線多媒體服務。對於高速無線個人網路，IEEE 802.15.3 為一新興的無線技術標準，此標準結合了低成本、省電、高傳輸速率以及強固的服務品質(QoS)保證等優勢。雖然IEEE 802.15.3 的媒體存取控制(MAC)層已經提供了服務品質保證的基本架構，然而他卻沒有提供資源管理的功能，例如: 頻寬配置、允入控制與資源排程。 為了滿足未來無線多媒體服務對於服務品質的要求，尤其是針對即時性多媒體服務的需求，以下三個問題為在 IEEE 802.15.3 多媒體網路上提供資源管理功能的主要挑戰。 (1) 如何針對不同的影片統計特性，以可調適(adaptively)的方式預測變動位元速率(VBR)的即時影片之頻寬需求? (2) 如何設計一個可以保證變動位元速率的即時影片之服務品質以及可以同時增進頻道使用率(channel utilization)的允入控制方案? (3) 如何排程變動位元速率的即時影片之流量以保證其服務品質且可以同時增進頻道使用率? 本論文之目的在於發展一系列適用於IEEE 802.15.3 多媒體網路的資源管理功能，以期可以保證傳輸的服務品質以及提升頻道使用率。對於問題(1)，我們針對變動位元速率的即時影片提出一個可以克服轉場(scene change)問題的可適性預測器，此可適性預測器基於一個可變 step-size LMS 演算法來開發。當影片轉場時，這個預測器有能力去適應快速的流量變化。基於這個可適性預測器，我們也針對變動位元速率的即時影片提出一個動態配置頻寬的方法。然而使用一個固定step-size LMS 演算法，其最佳化的參數必須根據不同的影片在預測之前事先決定以致於難以運用於即時性的服務。所以我們的可適性預測器朝向可以自動根據不同的影片來調整其最佳化參數來設計。 對於問題(2)，我們針對變動位元速率的即時影片提出一個基於線上觀測其流量總合的允入控制(MBAC)方法。其觀測程序將使用一個線性 Kalman filter 去估計變動位元速率的即時影片流量總合的統計參數。這些統計參數將被用於計算做為允入決策時所用之有效頻寬(effective bandwidth)。有效頻寬是一個對於已被使用資源的觀測值，其計算方式考慮了不同資源型態、變動的統計特性以及服務品質需求之間的相互取捨。MBAC 方法的目標在於可以同時保證變動位元速率的即時影片之服務品質以及提升頻道使用率。 最後，對於問題(3)，我們提出一個有效率的排程演算法。此演算法運用超寬頻技術提供的定位資訊與IEEE 802.15.3 標準提供的傳輸功率控制功能，在服務品質可以被保證下以期可以最大化系統的吞吐量(throughput)與提升頻道使用率。Recent progress in wireless technologies (e.g., Ultra-Wideband) has made it possible for people to enjoy high-quality wireless multimedia services at home. The IEEE 802.15.3 standard for high-rate wireless personal area networks (WPANs) is an emerging wireless technology that combines low cost and low power with high data rates and robust quality of service (QoS). Although the IEEE 802.15.3 MAC layer can provide a QoS supporting framework, it does not specify the functions of resource management such as bandwidth allocation, admission control and scheduling. In order to meet QoS requirements for future wireless multimedia services, especially for real-time multimedia services, the following problems are the main challenges of resource management for IEEE 802.15.3 multimedia networks. 1. (P1) To predict bandwidth requirements adaptively for real-time VBR videos. 2. (P2) To design an effective admission control scheme which can guarantee the QoS properties of multimedia traffics and improve channel utilization for real-time VBR videos. 3. (P3) To schedule VBR video traffics so that the QoS properties of multimedia traffics can be guaranteed and better channel utilization can result. The objective of this dissertation is to develop some functions of resource management for IEEE 802.15.3 multimedia networks, in order to support QoS transmissions for multimedia services and improve channel utilization. For (P1), we introduce a new adaptive VBR video predictor, based on a variable step-size LMS algorithm, which can overcome the problem caused by scene changes. We also propose a dynamic bandwidth allocation scheme using the VBR video predictor. The VBR video predictor is adaptive to rapid traffic variation while scene changes occur. Rather than using the fixed step-size adaptive LMS-type predictor, which is difficult to determine in advance the optimal parameters for different VBR video traffics, we enable the VBR video predictor to adjust its step size, automatically, according to the statistics of different VBR video traffics. For (P2), we propose an on-line measurement-based admission control (MBAC) scheme for aggregate VBR video traffics. A linear Kalman filter is to be used in the measurement process to estimate statistical parameters of aggregate VBR videos. The estimated statistical parameters are used to calculate the effective bandwidth for admission decision. The effective bandwidth, which is a measure of resource usage, represents a trade-off between sources of different types. When it is calculated, varying statistical characteristics and QoS requirements should be taken into account. The goal of the MBAC scheme is to achieve QoS guarantee for real-time VBR video traffics and improve channel utilization. Finally, for (P3), we propose an effective scheduling algorithm, which requires the location information provided by ultra-wideband technology and the transmission power control (TPC) supported by IEEE 802.15.3. With it, the system throughput can be maximized and the channel utilization can be enhanced, while the QoS requirements are satisfied.摘 要 ..................................................I Abstract ..............................................III Contents ................................................V Tables and Figures ....................................VII Chapter 1 Introduction ..................................1 1.1 IEEE 802.15.3 Wireless Multimedia Networks ..........1 1.2 Problems ............................................4 1.3 Overviews of Previous Work ..........................7 1.4 Dissertation Overview ..............................10 Chapter 2 Scene-Change Aware Resource Prediction for VBR Videos .................................................12 2.1 Related Work .......................................14 2.1.1 Model-Type Predictor .............................16 2.1.2 LMS-Type Predictor with Fixed Step Size ..........19 2.1.3 LMS-Type Predictor with Variable Step Size .......21 2.2 Scene-Change Aware Dynamic Bandwidth Allocation Scheme .................................................23 2.2.1 Problem Analysis for LMS-Type Predictors with Fixed Step Size ..............................................23 2.2.2 Modified Variable Step-size LMS ..................28 2.2.3 SCADBA ...........................................33 2.3 Performance Evaluation .............................34 2.3.1 Prediction Error (Comparisons) ...................36 2.3.2 Channel Utilization (Comparisons) ................40 2.3.3 Buffer Usage and Data Loss (Comparisons) .........43 Chapter 3 An On-Line Measurement-Based Admission Control ................................................46 3.1 Related Work .......................................48 3.1.1 Measurement Processes ............................49 3.1.2 Admission Criteria ...............................50 3.2 A MBAC with Aggregate Effective Bandwidth Estimation .............................................52 3.2.1 Network Model and Aggregate VBR Video Traffic Model ..................................................53 3.2.2 Measurement Process Using Kalman Filter ..........57 3.2.3 Admission Decision Using Aggregate Effective Bandwidth ..............................................61 3.3 Performance Evaluation .............................64 Chapter 4 A Spatial Reused Resource Allocation Mechanism ..............................................70 4.1 UWB ................................................71 4.2 Related Work .......................................72 4.3 A Resource Allocation Mechanism ....................75 4.3.1 Grouping .........................................77 4.3.2 CAC ..............................................81 4.3.3 BETM .............................................83 4.4 Performance Evaluation .............................87 Chapter 5 Discussion and Conclusion ....................93 References .............................................991364876 bytesapplication/pdfen-US資源管理流量預測允入控制排程多媒體resource managementtraffic predictionadmission controlschedulingmultimediathesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/53705/1/ntu-96-D91922007-1.pdf