Multicast resource allocation with min-rate requirements in OFDM systems  

作　　者：XU Wen-jun HE Zhi-qiang NIU Kai LIN Jia-ru WU Wei-ling 

机构地区：[1]School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China

出　　处：《The Journal of China Universities of Posts and Telecommunications》2010年第3期24-30,51,共8页中国邮电高校学报（英文版）

基　　金：supported by the National Basic Research Program of China (2007CB310604, 2009CB320401);the National Natural Science Foundation of China (60772108, 60702048);the Fundamental Research Funds for the Central Universities (BUPT2009RC0111)

摘　　要：This article addresses the multicast resource allocation problem with min-rate requirement constraints in orthogonal frequency division multiplexing （OFDM） systems. Due to the prohibitively high complexity for nonlinear and combinatorial optimization, the original problem is relaxed and reformulated to form a standard optimization problem. By theoretical derivation according to the Karush-Kuhn-Tucker （KKT） conditions, two propositions are presented as the necessary criteria for optimality. Furthermore, a two-step resource allocation scheme, including subcarrier assignment and power allocation, is proposed on a basis of the propositions for practical implementation. With the rain-rate based multicast group order, subcarriers are assigned in a greedy fashion to maximize the capacity. When subcarrier assignment is determined, the proposed power allocation can achieve the optimal performance for the rain-rate constrained capacity maximization with an acceptable complexity. Simulation results indicate that the proposed scheme approximates to optimal resource allocation obtained by exhaustive search with a negligible capacity gap, and considerably outperforms equal power distribution. Meanwhile, multicast is remarkably beneficial to resource utilization in OFDM systems.This article addresses the multicast resource allocation problem with min-rate requirement constraints in orthogonal frequency division multiplexing （OFDM） systems. Due to the prohibitively high complexity for nonlinear and combinatorial optimization, the original problem is relaxed and reformulated to form a standard optimization problem. By theoretical derivation according to the Karush-Kuhn-Tucker （KKT） conditions, two propositions are presented as the necessary criteria for optimality. Furthermore, a two-step resource allocation scheme, including subcarrier assignment and power allocation, is proposed on a basis of the propositions for practical implementation. With the rain-rate based multicast group order, subcarriers are assigned in a greedy fashion to maximize the capacity. When subcarrier assignment is determined, the proposed power allocation can achieve the optimal performance for the rain-rate constrained capacity maximization with an acceptable complexity. Simulation results indicate that the proposed scheme approximates to optimal resource allocation obtained by exhaustive search with a negligible capacity gap, and considerably outperforms equal power distribution. Meanwhile, multicast is remarkably beneficial to resource utilization in OFDM systems.

关 键 词：OFDM MULTICAST resource allocation min-rate requirements 

分 类 号：TN929.5[电子电信—通信与信息系统] O224[电子电信—信息与通信工程]