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 Nonconcave Utility Maximisation in the MIMO Broadcast Channel | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2009 Article ID 645041 13 pages doi 2009 645041 Research Article Nonconcave Utility Maximisation in the MIMO Broadcast Channel Johannes Brehmer and Wolfgang Utschick Associate Institute for Signal Processing Technische Universitiit Munchen 80333 Munich Germany Correspondence should be addressed to Johannes Brehmer brehmer@ Received 15 February 2008 Accepted 12 June 2008 Recommended by S. Toumpis The problem of determining an optimal parameter setup at the physical layer in a multiuser multiantenna downlink is considered. An aggregate utility which is assumed to depend on the users rates is used as performance metric. It is not assumed that the utility function is concave allowing for more realistic utility models of applications with limited scalability. Due to the structure of the underlying capacity region a two step approach is necessary. First an optimal rate vector is determined. Second the optimal parameter setup is derived from the optimal rate vector. Two methods for computing an optimal rate vector are proposed. First based on the differential manifold structure offered by the boundary of the MIMO BC capacity region a gradient projection method on the boundary is developed. Being a local algorithm the method converges to a rate vector which is not guaranteed to be a globally optimal solution. Second the monotonic structure of the rate space problem is exploited to compute a globally optimal rate vector with an outer approximation algorithm. While the second method yields the global optimum the first method is shown to provide an attractive tradeoff between utility performance and computational complexity. Copyright 2009 J. Brehmer and W. Utschick. 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.
