The management of the available bandwidth in a WiMAX system is one of the active research areas since it deals not only with the available bandwidth but also with the QoS requirements of different traffic classes. In this paper, a new bandwidth management scheme, named WiMAX Dual Cognitive Radio Scheme (WDCRS), is proposed. A cognitive radio approach is applied in order to obtain high bandwidth utilization and high throughput, and lower the blocking probability. An analytical model for performance analysis of the proposed scheme is developed. The results show that the proposed scheme achieves higher bandwidth utilization and lower the blocking probability compared to existing schemes.

WiMAX is a promising technology that provides broadband wireless access and supports high data rate, wide service coverage, and strong QoS. The uplink bandwidth management in WiMAX networks is one of the important issues that requires effectively allocating the bandwidth among contending users according to their services. In this paper, an efficient bandwidth management scheme, named WiMAX Dynamic Channel Allocation Scheme (WDCAS), is proposed. The scheme uses the cognitive radio for dynamic channel allocation in order to improve the bandwidth utilization while satisfying the QoS requirements. A queuing model based on the maximum entropy principle for performance analysis is introduced, and closed-form expressions for the state probability and the blocking probability are obtained. The simulation results show that the proposed scheme has a better performance than existing schemes, in terms of bandwidth utilization and network throughput.

PlanetLab is being used extensively to conduct experiments, implement and study large number of applications and protocols in Internet-like environment. With this increase in PlanetLab usage, there is a pressing need to have efficient way to setup and mange experiments. This paper proposes a graphical user interface-based tool, called ConTest, to setup and mange experiments over PlanetLab. ConTest enables PlanetLab users to setup experiment and collect results in a transparent and easy way. This tool also allows different measurements for different variables over the PlanetLab network. The paper discusses the design and implementation of ConTes and shows different scenarios.

In WiMAX networks managing the uplink access is an important issue as it deals not only with the available bandwidth but also with the QoS requirements of different traffic classes. This paper proposes a new scheme for bandwidth allocation in WiMAX systems, named WiMAX Dual Cognitive Radio Scheme (WDCRS). The proposed scheme uses cognitive radio in order to attain high bandwidth utilization and to increase the total throughput. For performance analysis, an analytical model is developed, and the effect of applying cognitive radio on different service classes is studied and the bandwidth utilization for each service class is analyzed. The results show that the proposed scheme provides higher bandwidth utilization and lower blocking probability in comparison to several existing schemes.