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 Autocorrelation Properties of OFDM Timing Synchronization Waveforms Employing Pilot Subcarriers | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2009 Article ID 538978 14 pages doi 2009 538978 Research Article Autocorrelation Properties of OFDM Timing Synchronization Waveforms Employing Pilot Subcarriers Oktay Ureten1 and Selcuk Tascioglu2 1 Communications Research Centre Terrestrial Wireless Systems Research Branch Ottawa ON Canada K2H 8S2 2Electronics Engineering Department Ankara University 06100 Ankara Turkey Correspondence should be addressed to Oktay Ureten Received 13 June 2008 Accepted 7 January 2009 Recommended by Marco Luise We investigate the autocorrelation properties of timing synchronization waveforms that are generated by embedded frequency domain pilot tones in orthogonal frequency division multiplex OFDM systems. The waveforms are composed by summing a selected number of OFDM subcarriers such that the autocorrelation function ACF of the resulting time waveform has desirable sidelobe behavior. Analytical expressions for the periodic and aperiodic ACF sidelobe energy are derived. Sufficient conditions for minimum and maximum aperiodic ACF sidelobe energy for a given number of pilot tones are presented. Several useful properties of the pilot design problem such as invariance under transformations and equivalence of complementary sets are demonstrated analytically. Pilot tone design discussion is expanded to the ACF sidelobe peak minimization problem by including various examples and simulation results obtained from a genetic search algorithm. Copyright 2009 O. Ureten and S. Tascioglu. 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 Timing synchronization is an essential task of an orthogonal frequency division multiplex OFDM receiver which requires alignment of the discrete Fourier transform .
