A Dynamic Power Scheme for Energy Efficiency and Throughput Enhancement in 802.16j MMR Networks

IEEE 802.16與其移動版本IEEE 802.16e之標準設計準則為針對single-hop網路架構所設計，雖然已日趨成熟，但仍有許多潛在問題待解決，因網路系統依照傳播距離的拉長，使得訊號強度呈現指數衰減的現象，造成資料速率大幅降低或發送功率增加。為此，802.16j提出以中繼站的方式，目的在於強化以IEEE 802.16e標準為基礎之WiMAX系統效能，協助降低整體WiMAX系統建置成本，增加系統拓撲彈性，並向下與802.16e相容。因802.16j提供較大的基地台涵蓋範圍，傳送端與接收端仍屬於遠距離傳輸，需使用較高的功率與基地台連線才能保有相同的連線品質。然而，移動裝置基於電池容量的緣故，通常會使用較低功率來節省電量的使用。本論文中，我們以IEEE 802.16組織所發展之SUI Model為通道模型，加以估算各種情況下之路徑損失，並模擬出不同的中繼站佈署方式及變動功率下相對應之資料速率。The IEEE 802.16 and its mobile service enhancement 802.16e, have well defined specifications for legacy single-hop networks. Although it matured gradually, there are still many potential problems. With the longer distance, the throughput decreases obviously due to the significant loss of signal strength along the propagation path. Because of this, IEEE 802.16j made the way by using intermediate relay stations based on 802.16e. This enhances the system throughput and reduces the overall cost to build WiMAX system. Furthermore, it increases flexibility in system topology and it is downward compatible with 802.16e.The base stations of 802.16j provide a large coverage. This makes larger distance between transmitters and receivers, resulting in the need of higher power level to maintain the same connection quality. However, mobile devices usually use lower power to save the use of electricity due to the limitation of battery capacity. In this thesis, we use SUI model which is developed under IEEE 802.16 Working Group to calculate the pass loss in different conditions. We simulate the data rates corresponding to the changes in transmission power and positions of RSs.中文摘要 IIbstract IIIist of Figure Vist of Tables VIhapter 1 Introduction 1.1 Background 1.2 Motivation 3.3 Thesis Organization 4hapter 2 Background Knowledge 5.1 Introduction of WiMAX 5.2 WiMAX Specifications 6.3 IEEE 802.16j Multi-hop Relay Networks 7.3.1 Frame Structure 8.3.2 Coding and Modulation 12hapter 3 Methodology 15.1 Path loss 15.2 SUI Model 15.3 Receiver Requirement 19.3.1 SNR Required 19.3.2 The SNR at the Receiver 21.4 MAC Performance 23.5 The Schemes of Power Selection 25hapter 4 Result 28.1 Power Ratio 28.2 Throughput Analysis 31.3 Simulation Results 33hapter 5 Conclusion and Future works 41eference 4