An IEEE 802.16 MAC Layer Downlink Scheduler Implemented in NS3 to Improve the Performance of Real-Time and Non-Real-Time Traffic Transmission

Supporting a high quality multimedia transfer has become a significant challenge for telecommunication industry. Numerous efforts have been done in different network layers to improve system performance based on real-time traffic transmission. The main contribution of this paper is to introduce a downlink packet scheduler for IEEE 802.16 standard MAC layer that improves the QoS of real-time traffic while not deteriorating the performance of non-real-time data. This scheduler categorizes the packets into three priority levels. Unlike the existing priority- based schedulers, in this model a budget calculation process is provisioned to prevent the low priority data from starving. The scheduler has been developed in a simulated IEEE 802.16 network scenario in NS3, hosting mixed types of traffic. Extensive simulation experiments show that the proposed scheduling model prevents bandwidth misuse which significantly improves the QoS parameters of real-time traffic comparing to a conventional packet scheduler.The scheme and conclusions are readily extendable to other 4G standards using the described mapping mechanism.