Title: A Cross-Layer Framework for Overhead Reduction, Traffic Scheduling, and Burst Allocation in IEEE 802.16 OFDMA Networks
Authors: Liang, Jia-Ming
Chen, Jen-Jee
Wang, You-Chiun
Tseng, Yu-Chee
Department of Computer Science
Keywords: Burst allocation;cross-layer design;fair scheduling;IEEE 802.16;Worldwide Interoperability for Microwave Access orthogonal frequency-division multiple access (WiMAX OFDMA)
Issue Date: 1-May-2011
Abstract: IEEE 802.16 orthogonal frequency-division multiple access (OFDMA) downlink subframes have a special 2-D channel-time structure. Allocation resources from such a 2-D structure incur extra control overheads that hurt network performance. Existing solutions try to improve network performance by designing either the scheduler in the medium access control 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" both the scheduler and the burst allocator to efficiently reduce overheads and improve network performance. Under the partial-usage-of-subcarriers model, we propose a cross-layer framework that 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, which is more complete and efficient than prior studies. Both the scheduler and the burst allocator are tightly coupled together to solve the problem of arranging resources to data traffic. Given available space and bucket design from the burst allocator, the scheduler can well utilize the frame resource, reduce real-time traffic delays, and maintain fairness. On the other hand, with priority knowledge and resource assignment from the scheduler, the burst allocator can efficiently arrange downlink bursts to satisfy traffic requirements with low complexity. Through analysis, the cross-layer framework is validated to give an upper bound to overheads and achieve high network performance. Extensive simulation results verify that the cross-layer framework significantly increases network throughput, maintains long-term fairness, alleviates real-time traffic delays, and enhances frame utilization.
URI: http://dx.doi.org/10.1109/TVT.2011.2125808
ISSN: 0018-9545
DOI: 10.1109/TVT.2011.2125808
Volume: 60
Issue: 4
Begin Page: 1740
End Page: 1755
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