CADA: channel and delay aware scheduler for real-time applications in WiMAX networks

Scheduling is the core of the worldwide interoperability for microwave access (WiMAX) technology that directly affects the performance of the network. In this study, we focus on scheduling and present a novel algorithm called the channel and delay aware scheduler (CADA) for real-time applications, such as voice over Internet protocol, videoon-demand, and video streaming. CADA has 2 important modules: wireless and network delay monitoring tools. The wireless module, including the compensation and channel state monitoring modules, increases the network throughput and provides fairness among all of the flows in the network. The network delay monitoring tool calculates the estimated network delay of the paths and uses this estimated delay to calculate the packet deadline for meeting the delay requirement of the real-time application flow. The main objectives of this study are: a) fulfilling the delay requirements of the realtime applications using a network monitoring tool, b) providing opportunistic scheduling by taking the channel conditions and network delay into account, and c) surveying the recent trends of the existing scheduling algorithms in WiMAX as guidelines for researchers who are interested in the scheduling algorithms. The simulation results show that CADA improves the performance of the real-time applications by taking the delay metric into account, increasing the network throughput of the WiMAX network, and providing the long-term fairness among all of the flows.