Performance Evaluation And Improvement Of MAC In Wireless Network

Because wireless systems have the flexibility and the capacity to address broad geographic areas without the costly infrastructure deployment, the technology may lead to more ubiquitous broadband access. Such systems have been the focus of industry and academy. With the severe impairments such as path loss, multi-path effect, fading and noise, wireless links limit the overall system throughput considerably compared to wireline alternatives. Being responsible for assigning radio resource and controlling the access of end users, MAC layer has a great effect on the performance of wireless networks. In this dissertation, we investigate the performance of MAC layer protocols and propose some new MAC solutions in the context of WMANs and WPANs systems. The main contributions are as follows:1. IEEE 802.16 adopts TDMA and contention-based reservation of resource in its uplink MAC layer. Thus there are contentions and collisions between SSs, and the performance is inevitably deteriorated. A fast and efficient backoff algorithm DBC (Dynamical Backoff Control) is proposed to solve the problem. In DBC, BS controls the backoff ranges dynamically. As a result, the successful rate of sending request messages in each frame is increased, the data throughput of MAC layer is increased, and the mean...