tailieunhanh - Báo cáo hóa học: " Research Article Power Allocation and Admission Control in Multiuser Relay Networks via Convex Programming: Centralized and Distributed Schemes"

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 Power Allocation and Admission Control in Multiuser Relay Networks via Convex Programming: Centralized and Distributed Schemes | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID 901965 12 pages doi 2009 901965 Research Article Power Allocation and Admission Control in Multiuser Relay Networks via Convex Programming Centralized and Distributed Schemes Khoa T. Phan 1 Long Bao Le 2 Sergiy A. Vorobyov 3 and Tho Le-Ngoc4 1 Department of Electrical Engineering California Institute of Technology Caltech Pasadena CA 91125 USA 2 Department of Aeronautics and Astronautics Massachusetts Institute of Technology Cambridge MA 02139 USA 3 Department of Electrical and Computer Engineering University of Alberta Edmonton AB Canada T6G 2V4 4 Department of Electrical and Computer Engineering McGill University Montreal QC Canada H3A 2A7 Correspondence should be addressed to Sergiy A. Vorobyov svor@ Received 27 November 2008 Accepted 6 March 2009 Recommended by Shuguang Cui The power allocation problem for multiuser wireless networks is considered under the assumption of amplify-and-forward cooperative diversity. Specifically optimal centralized and distributed power allocation strategies with and without minimum rate requirements are proposed. We make the following contributions. First power allocation strategies are developed to maximize either i the minimum rate among all users or ii the weighted-sum of rates. These two strategies achieve different throughput and fairness tradeoffs which can be chosen by network operators depending on their offering services. Second the distributed implementation of the weighted-sum of rates maximization-based power allocation is proposed. Third we consider the case when the requesting users have minimum rate requirements which may not be all satisfied due to the limited-power relays. Consequently admission control is needed to select the number of users for further optimal power allocation. As such a joint optimal admission control and power allocation problem is combinatorially hard a .