Research On The Admission Control Mechanism In IEEE 802.16 System

The Broadband Wireless Metropolitan Area Network protocol of IEEE 802.16 is a developing global standard for broadband wireless access technique, which can give a good solution of the"last mile"access. IEEE 802.16 MAC protocol defines a perfect signaling switching mechanism, the service types based on Quality of Service and the bandwidth request/allocation mechanism, etc. However the control mechanisms such as admission control mechanism and packet scheduling algorism are left to equipment providers to realize. Main task of admission control mechanism which is an important part of management mechanisms for network resource is to determine whether a new connection can be allowed according to the current state of network.This thesis not only takes an analysis for the IEEE 802.16 protocol and the current studying results on the admission control mechanism, but also simulates an IEEE 802.16 environment and designs an admission control module. On this basis, we accomplished emphatically a weighted fair adaptive admission control algorism which will provide different services for different weights of service-flows by adaptive changes in admission strategy. Finally we evaluate this algorism from the angles of Connection Acceptance Ratio, Average Degrading Ratio and Bandwidth Utilization Ratio and so on. The simulations indicate that the algorism firstly serves the flows with high weight in order to improve bandwidth utilization, and restricts the flows with low weight to ensure the interests of all flows in the network.