Mobile broadband networks are continuously faced with the challenge of limited resources due to the increasing demand for high speed Internet services. To manage these resources, call admission control (CAC) which determines whether or not a connection request should be accepted or rejected is one of the resource management techniques usually deployed. A Dynamic QoS-aware CAC algorithm was recently proposed to improve resource utilization. However, the algorithm detects congestion of the network only after it has occurred, which leads to increase in blocking probability and thus lead to reduction in throughput. In this paper, a congestion control call admission control (CC-CAC) algorithm is proposed to reduce call blocking and increase throughput of all connection classes. The CC-CAC employs a congestion control mechanism that regulates the base station buffer to operate at a target threshold. It also employs a dynamic bandwidth degradation mechanism to degrade the resources of the admitted connections when resources are not sufficient to admit more connections. The algorithm is evaluated using simulation. The results show that the proposed scheme outperforms the benchmark scheme in terms of decrease in blocking probability and increase in throughput for all connection classes.
Modeling and Optimization of Wireless Channel in High-Speed Railway Terrain
