tailieunhanh - Báo cáo hóa học: " Research Article On Power Allocation for Parallel Gaussian Broadcast Channels with Common Information"

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 On Power Allocation for Parallel Gaussian Broadcast Channels with Common Information | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID 482520 15 pages doi 2009 482520 Research Article On Power Allocation for Parallel Gaussian Broadcast Channels with Common Information Ramy H. Gohary1 2 and Timothy N. Davidson1 1 Department of Electrical and Computer Engineering McMaster University Hamilton ON Canada 2 Communications Research Centre Industry Canada Ottawa ON Canada Correspondence should be addressed to Ramy H. Gohary rgohary@ Received 28 October 2008 Accepted 13 March 2009 Recommended by Sergiy Vorobyov This paper considers a broadcast system in which a single transmitter sends a common message and independent particular messages to K receivers over N unmatched parallel scalar Gaussian subchannels. For this system the set of all rate tuples that can be achieved via superposition coding and Gaussian signalling SPCGS can be parameterized by a set of power loads and partitions and the boundary of this set can be expressed as the solution of an optimization problem. Although that problem is not convex in the general case it will be shown that it can be used to obtain tight and efficiently computable inner and outer bounds on the SPCGS rate region. The development of these bounds relies on approximating the original optimization problem by a convex Geometric Program GP and in addition to generating the bounds the GP also generates the corresponding power loads and partitions. There are special cases of the general problem that can be precisely formulated in a convex form. In this paper explicit convex formulations are given for three such cases namely the case of 2 users the case in which only particular messages are transmitted in both of which the SPCGS rate region is the capacity region and the case in which only the SPCGS sum rate is to be maximized. Copyright 2009 R. H. Gohary and T. N. Davidson. This is an open access article distributed under the Creative Commons .