Research And Implementation Of The Admission Control And Other Key Technologies Of Wireless Access Network

As the emergence and development of network multimedia services with high speed and high quality, the requirement of bandwidth grows rapidly, while the requirement of mobility and flexibility of network access grows also. Therefore, the integration of fiber and wireless access network is in accordance with the trend of the access network well as becoming more broadband and ubiquitous. WiMAX as a mainstream broadband wireless access technology has features of high spectral efficiency and transmission rate. It is suitable for broadband Internet access and mobile video services and promising a bright applied future. Admission control of WiMAX is an important mechanism for reducing the network congestion. It allocates bandwidth reasonably on conditions of limiting bandwidth resources for guaranteeing the quality of multi-user and multi-service and improves the utilization ratio of network resources.This paper mainly focus on the design and realization of the core functions for EPON and WiMAX integrated new-style access system, such as the implementation of the driver of PHY PCI device and MAC protocol of WiMAX and the algorithm research of admission control, with the supporting of National 863 project "The key technology of dynamic heterogeneous integrated access network supporting P2P and multicasting"The major work of this paper is listed as follows.1) The working mechanism of WiMAX time-division multiplexing and MAC layer protocol, which includes ranging, register and admission control has been studied, the overall implementation scheme of EPON and WiMAX integrated access network has been designed. The demand analysis and design development of program of PCI device driver of physical layer on the WiMAX sub-system have been accomplished, and the functions of RF transceiver and physical layer ranging has been implemented. The result of the driver has been proved to be met the demand of design after being tested and verified.2) According to the structure and characters of merged network, the demand analysis of the embedded software of WiMAX has been completed and the overall structure of software for MAC protocol of WiMAX has been determined. Furthermore, the demand analysis and design development and unit function test of the service priority sort sub-module, the admission control sub-module and manage configuration interface sub-module have been described in detail. The merged access network passed the system test and the function and performance meeted the design requirements well.3) According to the characteristics of the wireless access system, the resource allocation algorithm of the WiMAX system has been researched and an adjusted admission control algorithm based on the blocking probability in the access cell self-adaptively and combined with dynamic bandwidth allocation has been proposed. The algorithm pursued comprehensive optimal performance which included resource utilization, blocking probability and user fairness. The performance advantages of the improved algorithm have been proved by the Matlab simulation platform.