tailieunhanh - Báo cáo hóa học: " Research Article Identification of LOS in Time-Varying, Frequency Selective Radio Channels"

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 Identification of LOS in Time-Varying, Frequency Selective Radio Channels | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 195948 14 pages doi 2008 195948 Research Article Identification of LOS in Time-Varying Frequency Selective Radio Channels Serhan Yarkan and Huseyin Arslan Department of Electrical Engineering University of South Florida 4202 E. Fowler Avenue ENB-118 Tampa FL 33620 USA Correspondence should be addressed to Serhan Yarkan syarkan@ Received 16 August 2007 Revised 15 December 2007 Accepted 22 February 2008 Recommended by Chia-Chin Chong A method is proposed to identify the existence of line-of-sight LOS for time-varying frequency selective radio channels. The proposed method considers the second-order statistical characteristics of underlying process in the channel taps. Identification is established by comparing the autocorrelation coefficients of the first tap with those of any other tap when the other tap reaches its coherence time. Numerical results and related discussions are presented considering several practical scenarios. Copyright 2008 S. Yarkan and H. Arslan. 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 One of the most important properties of propagation channels for wireless communications is the presence of line-of-sight LOS between the transmitter and receiver. Having LOS affects some of the crucial parameters of both the transmission system design and the applications. Transmission frequency or wavelength is one of the parameters exemplifying the impact of LOS on the system design. Radio transmissions over millimeter waves above 10 GHz require LOS whereas LOS is not necessary in microwave bands. This stems from the fact that significant transmission losses occur while millimeter waves travel through environment. In millimeter wave bands .