tailieunhanh - Báo cáo hóa học: "Research Article Transmission Strategies in MIMO Ad Hoc Networks"

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 Transmission Strategies in MIMO Ad Hoc Networks | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID 128098 11 pages doi 2009 128098 Research Article Transmission Strategies in MIMO Ad Hoc Networks Khalil Fakih Jean-Francois Diouris and Guillaume Andrieux IREENA Ecole Polytechnique de l Universite de Nantes BP 50609 Nantes France Correspondence should be addressed to Khalil Fakih Received 1 December 2008 Revised 15 April 2009 Accepted 22 June 2009 Recommended by Shuguang Cui Precoding problem in multiple-input multiple-output MIMO ad hoc networks is addressed in this work. Firstly we consider the problem of maximizing the system mutual information under a power constraint. In this context we give a brief overview of the nonlinear optimization methods and systematically we compare their performances. Then we propose a fast and distributed algorithm based on the quasi-Newton methods to give a lower bound of the system capacity of MIMO ad hoc networks. Our proposed algorithm solves the maximization problem while diminishing the amount of information in the feedback links needed in the cooperative optimization. Secondly we propose a different problem formulation which consists in minimizing the total transmit power under a quality of signal constraint. This novel problem design is motivated since the packets are captured in ad hoc networks based on their signal-to-interference-plus-noise ratio SINR values. We convert the proposed formulation into semidefinite optimization problem which can be solved numerically using interior point methods. Finally an extensive set of simulations validates the proposed algorithms. Copyright 2009 Khalil Fakih 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. 1. Introduction Recently MIMO ad hoc networks have attracted an .