tailieunhanh - Báo cáo hóa học: " Research Article Multicell Downlink Capacity with Coordinated Processing"

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 Multicell Downlink Capacity with Coordinated Processing | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 586878 19 pages doi 2008 586878 Research Article Multicell Downlink Capacity with Coordinated Processing Sheng Jing 1 David N. C. Tse 2 Joseph B. Soriaga 3 Jilei Hou 3 John E. Smee 3 and Roberto Padovani3 1 Laboratory for Information and Decision Systems LIDS Massachusetts Institute of Technology MIT Cambridge MA 02139 USA 2 Electrical Engineering and Computer Science Department University of California Berkeley CA 94720-1770 USA 3 Corporate R D Division Qualcomm Incorporated 5775 Morehouse Drive San Diego CA 92121 USA Correspondence should be addressed to Sheng Jing sjing@ Received 31 July 2007 Revised 15 January 2008 Accepted 13 March 2008 Recommended by Huaiyu Dai We study the potential benefits of base-station BS cooperation for downlink transmission in multicell networks. Based on a modified Wyner-type model with users clustered at the cell-edges we analyze the dirty-paper-coding DPC precoder and several linear precoding schemes including cophasing zero-forcing ZF and MMSE precoders. For the nonfading scenario with random phases we obtain analytical performance expressions for each scheme. In particular we characterize the high signal-to-noise ratio SNR performance gap between the DPC and ZF precoders in large networks which indicates a singularity problem in certain network settings. Moreover we demonstrate that the MMSE precoder does not completely resolve the singularity problem. However by incorporating path gain fading we numerically show that the singularity problem can be eased by linear precoding techniques aided with multiuser selection. By extending our network model to include cell-interior users we determine the capacity regions of the two classes of users for various cooperative strategies. In addition to an outer bound and a baseline scheme we also consider several locally cooperative transmission approaches. The .