tailieunhanh - Báo cáo hóa học: " Research Article Uplink Cross-Layer Scheduling with Differential QoS Requirements in OFDMA Systems"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: IResearch Article Uplink Cross-Layer Scheduling with Differential QoS Requirements in OFDMA Systems | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2010 Article ID 168357 10 pages doi 2010 168357 Research Article Uplink Cross-Layer Scheduling with Differential QoS Requirements in OFDMA Systems Bo Bai 1 2 Wei Chen 2 Zhigang Cao 2 and Khaled Ben Letaief1 1 Department of Electronic and Computer Engineering The Hong Kong University of Science Technology Clear Water Bay Kowloon Hong Kong 2 Department of Electronic Engineering Tsinghua National Laboratory for Information Science and Technology TNList Tsinghua University Beijing 100084 China Correspondence should be addressed to Bo Bai eebob@ Received 15 January 2010 Revised 29 June 2010 Accepted 21 September 2010 Academic Editor Mohammad Shikh-Bahaei Copyright 2010 Bo Bai et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Fair and efficient scheduling is a key issue in cross-layer design for wireless communication systems such as 3GPP LTE and WiMAX. However few works have considered the multiaccess of the traffic with differential QoS requirements in wireless systems. In this paper we will consider an OFDMA-based wireless system with four types of traffic associated with differential QoS requirements namely minimum reserved rate maximum sustainable rate maximum latency and tolerant jitter. Given these QoS requirements the traffic scheduling will be formulated into a cross-layer optimization problem which is convex fortunately. By separating the power allocation through the waterfilling algorithm in each user this problem will further reduce to a kind of continuous quadratic knapsack problem in the base station which yields low complexity. It is then demonstrated that the proposed cross-layer method cannot only guarantee the application layer QoS requirements but also minimizes the integrated .