Research Of QoS Guarantee Scheme In WiMAX System

WiMAX is a promising wireless broadband technology for the next generation last mile access. Though Quality of service (QoS) is guaranteed by the standard which defines five types of multimedia traffic classes, it doesn't define any specific admission control strategy and scheduling algorithm which are left to venders to design, and they have been becoming the research hotspot and many institutes and colleges begin to study QoS guarantee mechanism. A variety of admission control strategy and scheduling algorithm have been proposed and implemented at the MAC layer, but none of them is perfect. In this paper, we propose a novel improved admission control strategy based on resource reserved mechanism and design an effective and fair four-level scheduling architecture, which could provide predefined QoS for different service classes. Detailed simulation experiments are provided to validate fairness and effectiveness of proposed QoS guarantee strategy and results show it can achieve the desired effect.Background, basic knowledge and key technology in WiMAX are first introduced. Following are PHY and MAC layers in WiMAX system. Admission control strategy and scheduling algorithm which have been proposed will be introduced in detail in later chapters, and analyses their advantages and disadvantages. And we propose a new improved strategy based on current schemes. Finally, we validate feasibility and effectiveness of our new strategy via many simulations.