A Cross-Layer Qos Based Scheduling Algorithm WRR Design in Wimax Base Stations

Abstract

The IEEE 802.16 standard defines a wireless broadband access network technology called Wimax. It introduces several advantages, one of which is the support for Quality of Service (QoS) at the MAC level. To ensure meeting the QoS requirements, the 802.16 base stations must run some algorithms to allocate slots between connections. Call admission and scheduling are the strongest tools in our hand to ensure QoS. We propose an efficient design architecture that is capable of allocating slots based on the QoS requirements, bandwidth request sizes, and the 802.16 network parameters. To test the proposed solution, we have implemented a cross layer between the 802.16 MAC and the network layers in the NS-2 simulator and, then in RTL level with VHDL to be designed in FPGA. Several simulation scenarios are presented. According to the simulation results, the proposed scheduling solution ensures the QoS requirements of all 802.16 service classes. The solution shares free resources weighted fairly and demonstrates work-conserving behavior. The proposed design in this paper was analyzed: simulation results show a significant performance improvement in terms of overall throughput and delay when compared to recently published work.

A Survey and Analysis on Scheduling Algorithms in IEEE 802. 16e (WiMAX) Standard

“…In [13], [14], [20] & [21] WRR procedure, packets are categorized into different service classes and then assigned to a queue that can be assigned different percentage of bandwidth and served based on Round Robin order as shown in Figure 4. This algorithm address the problem of starvation by guarantees that all service classes have the ability to access at least some configured amount of network bandwidth.…”

“…It is noted that WRR technique shows the most favorable results as the average jitter has low reading (0.136s). [21] Says WRR is very useful algorithm for which the scheduler uses it only for one time. But when the case of hierarchy of WRR then it is challenging task to use because the peer-connection QoS requirements must be translated into scheduler at each level and when the network is dynamic, buffer length & trade-off between the throughput and queue delay is difficult to control.…”