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: Research Article Cross-Layer Optimal Rate Allocation for Heterogeneous Wireless Multicast | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID 467182 16 pages doi 2009 467182 Research Article Cross-Layer Optimal Rate Allocation for Heterogeneous Wireless Multicast Amr Mohamed1 and Hussein Alnuweiri2 1 Department of Computer Engineering Qatar University . Box2317 Doha Qatar 2 Department of Electrical Engineering Texas A M University at Qatar . Box 23874 Doha Qatar Correspondence should be addressed to Amr Mohamed amrm@ Received 30 March 2008 Revised 5 December 2008 Accepted 12 January 2009 Recommended by Ekram Hossain Heterogeneous multicast is an efficient communication scheme especially for multimedia applications running over multihop networks. The term heterogeneous refers to the phenomenon when multicast receivers in the same session require service at different rates commensurate with their capabilities. In this paper we address the problem of resource allocation for a set of heterogeneous multicast sessions over multihop wireless networks. We propose an iterative algorithm that achieves the optimal rates for a set of heterogeneous multicast sessions such that the aggregate utility for all sessions is maximized. We present the formulation of the multicast resource allocation problem as a nonlinear optimization model and highlight the cross-layer framework that can solve this problem in a distributed ad hoc network environment with asynchronous computations. Our simulations show that the algorithm achieves optimal resource utilization guarantees fairness among multicast sessions provides flexibility in allocating rates over different parts of the multicast sessions and adapts to changing conditions such as dynamic channel capacity and node mobility. Our results show that the proposed algorithm not only provides flexibility in allocating resources across multicast sessions but also increases the aggregate system utility and improves the overall system throughput by .
