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: Differential Detection of Space-Time Spreading with Two Transmit Antennas | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2006 Article ID 70509 Pages 1-10 DOI WCN 2006 70509 Differential Detection of Space-Time Spreading with Two Transmit Antennas Tao Shi and Lei Cao Department of Electrical Engineering University of Mississippi University MS 38677 USA Received 8 June 2005 Revised 18 October 2005 Accepted 5 December 2005 Recommended for Publication by Lee Swindlehurst A differential detection scheme for space-time spreading with two transmit antennas is proposed. The scheme does not require channel state information at either the transmitter or the receiver. With segmentation and preamble symbols padded at the transmitter the receiver recovers the information using differential detection. Both phase-shift keying PSK and quadrature amplitude modulation QAM signals are considered. The proposed scheme achieves two-level transmit diversity gain with low complexity and saves the use of channel estimation while having about 3 dB performance loss as compared to the coherent detection scheme. When multiple receive antennas exist additional receive diversity gain can be achieved along with the transmit diversity gain. The scheme works fine under block-fading channel as well as slow Rayleigh fading channel which is a popular scenario for high-rate data communications. The system performance for different segment sizes channel fading speeds modulation methods and numbers of receive antennas is studied through simulations. Copyright 2006 T. Shi and L. Cao. 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 Receive diversity has been well known as one powerful technique to mitigate the effect of fading and shadowing for high-rate data transmission over wireless hostile channels. The classical approach is to use multiple .
