A Study And Optimization Of Cross-Layer Framework For QoS In IEEE 802.16 Networks

Wireless Metropolitan Area Network (WMAN) becomes to be an important part of global telecommunications. As is well known, WiMAX based on IEEE 802.16, as an available access method for WMAN, has drawn a great deal of attention for its better performance and brilliant future in a broad of areas.A new cross-layer framework for QoS in 802.16d/e networks, which could successfully achieve QoS guarantees and improve the performances of different types of services in single BS PMP application, is proposed in this thesis.At first, we generalize the application background and current development of WiMAX systems and IEEE 802.16. Then, technology of QoS is analyzed specially to IEEE 802.16d/e, including its basic implementation, technical highlight of the framework and packet scheduling theory. After that, we deal with technology of cross-layer; and also generate a new kind of cross-layer framework for QoS in 802.16 networks, where all function modules are considered according to uplink and downlink. Finally, the four main function modules of the proposed framework are discussed in details here, including a new mapping rule between IP and MAC services as an assistant buffer management for better system performance under low complexity, IP fragments control for MAC frame processing with less wastage, call admission control based on threshold and SINR to achieve high system validity and stability, and also a hierarachical packet scheduling algorithm for both enhanced QoS guarantees and fairness. At the same time, we realize the simulation instances with NS to display the advantages of the proposed scheme.