Improve WiMAX Network Performance Using Cross-Layer Framework

WiMAX OFDMA downlink subframes have a special 2-D channel time structure. The resource allocations from this structure incur extra control overheads that hurt network performance. Existing solutions try to improve network performance by designing either the scheduler in the MAC layer or the burst allocator in the physical layer, but the efficiency of overhead reduction is limited. In this paper, we point out the necessity of “codesigning”(i.e.) both the scheduler and the burst allocator are combined. For that, we propose a cross-layer framework under the PUSC model. It covers overhead reduction, real-time and non-real-time traffic scheduling, and burst allocation .The framework includes a two-tier priority-based scheduler and a bucket-based burst allocator. By coupling these scheduler and burst allocator, it solves the problem of resource allocation for data traffic. By codesigning the scheduler and burst allocator, the scheduler can well utilize the frame space and, reduce IE overheads with the help of burst allocator. The burst allocator satisfy traffic requirements such as real-time delay constraints ,the burst allocator has to arrange bursts based on the traffic scheduling knowledge from the scheduler. and maintain fairness. Through analysis, the cross-layer framework significantly increases network throughput maintain its long-term fairness, alleviates real-time traffic delays, and enhances frame utilization. Index Terms — Burst allocation, cross-layer design, fair scheduling,IEEE 802.16, Worldwide Interoperability for Microwave Access orthogonal frequency-division multiple access (WiMAX OFDMA). ——————————  ——————————