Study On Media Access Control And Traffic Scheduling Algorithm In Wireless Communication System

With widely applications of Wireless Mesh Network (WMN), the research of QoS in WMN has become a hot topic. Media access control (MAC) and packet scheduling are important data link layer techniques, which provide QoS guarantee. Because of the characteristic of multihop and distributed control in WMN, the typical data link layer techniques are not available to WMN. So, the MAC and scheduling are discussed for WMN. This dissertation's work includes a broadband wireless mesh network equipment designing and scheduling algorithms theoretically researching to improve the TIMELY model of packet scheduling algorithms. The major work and innovations are shown as follows:1. According to the characteristics of WMN, the theory and requirement of cross-layer design and its applications in WMN is expatiated. Consider the background of subject, classification of MAC protocol is introduced. Compaired the MAC designs in TDD/TDMA WMN.2. Summarized the packet scheduling algorithms, the mathematical analysis of scheduling algorithms is completed. By reviewing packet scheduling algorithms used in wired and wireless networks, the TIMELY model of packet scheduling algorithms in wireless network is discussed.3. Participated in designing of a broad-band wireless network product and completed the design of MAC protocol.4. Consider the non-division of traffic in TIMELY model and the multi-hop traffic of WMN, a hierarchical scheduling mechanism for traffic is designed. It provides classification of traffic and distinguishes between non-direct traffic and direct traffic, to provide different QoS guarantee in WMN. Based on the hierarchical classification of traffic, the channel state in TIMELY model is improved from 2-state to N-state, according to BER. Match the QoS of traffic and the channel state to complete the improvements of scheduling model.