Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
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 Efficient Feedback via Subspace-Based Channel Quantization for Distributed Cooperative | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2008 Article ID 847296 13 pages doi 10.1155 2008 847296 Research Article Efficient Feedback via Subspace-Based Channel Quantization for Distributed Cooperative Antenna Systems with Temporally Correlated Channels Jee Hyun Kim 1 Wolfgang Zirwas 1 and Martin Haardt2 1 Nokia Siemens Networks GmbH Co. KG St.-Martin-Strasse 76 81541 Munich Germany 2 Communications Research Laboratory Ilmenau University of Technology P.O. Box 100565 98684 Ilmenau Germany Correspondence should be addressed to Jee Hyun Kim jee.kim@nsn.com Received 15 June 2007 Revised 28 September 2007 Accepted 23 November 2007 Recommended by Ana Perez-Neira It is one of the biggest challenges of distributed cooperative antenna COOPA systems to provide base stations BSs with downlink channel information for transmit filtering precoding . In this paper we propose a novel feedback scheme via a subspace-based channel quantization method. The proposed scheme adopts the chordal distance as a channel quantizer criterion so as to capture channel characteristics represented by subspaces spanned by the channel matrix. We also propose a combined feedback scheme which is based on the hierarchical codebook construction method in an effort to reduce the feedback overhead by exploiting the temporal correlation of the channel. The proposed methods are tested for distributed COOPA systems in terms of simulations. Simulation results show that the proposed subspace-based channel quantization method outperforms the analog pilot retransmission method and the combined feedback scheme performs as well as the permanent full-feedback scheme with a much smaller amount of uplink resources. Copyright 2008 Jee Hyun Kim 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
