Orthogonal frequency-division multiplexing ultra wide band system anti-multipath timing synchronization scheme
An orthogonal frequency division and timing synchronization technology, applied in multi-frequency code systems and other directions, can solve the problems of increased position uncertainty, deterioration of timing synchronization performance, etc., to achieve low complexity, reduce implementation costs, and ensure the effect of demodulation performance
Inactive Publication Date: 2015-06-17
TIANJIN POLYTECHNIC UNIV
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However, in a channel with multi-path delay, since the timing position has the strongest energy instead of the first path, the timing position often lags behind and the uncertainty of the position increases, which deteriorates the timing synchronization performance sharply.
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[0042] The invention is applied in the OFDM ultra-wideband system of the IEEE802.15.3c standard, and the system is simulated based on Matlab / Simulink.
[0043] As shown in Figure 2(a)(b)(c), the autocorrelation sidelobe of a single Golay sequence is larger, while the non-periodic autocorrelation of Golay complementary sequence has all sidelobe zero due to complementary cancellation. This ideal complementary autocorrelation property of Gray's complementary sequence is very suitable for high-precision timing synchronization.
[0044] Figure 3(a) shows the waveforms of the normalized sliding autocorrelation values calculated in the frame detection and coarse timing phases. It can be seen that when the correlation window length is 128, there is an obvious falling edge between the first part of the preamble frame synchronization sequence (SYNC) and the second part of the frame delimiter (SFD). Figure 3(b) shows the waveform diagram of the separated autocorrelation value calculat...
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The invention studies and designs a timing synchronization scheme capable of resisting channel multipath interference according to an orthogonal frequency-division multiplexing ultra wide band system based on the complementary correlation properties of a precursor Golay complementary sequence. Firstly, normalization sliding self-correlation values of two continuous windows are calculated through a repeated training sequence of a precursor, frame detection is carried out based on a falling edge of a correlation peak, and a coarse timing position is determined. Then, a specific normalization separation maximum correlation calculation method is designed through a Golay complementary sequences structure in the training sequence, and a fine timing position is determined by averaging the obtained correlation peak values. Simulation indicates that under a CM1 multipath channel module with a low signal to noise ratio, the root-mean-square error of a rear residual timing deviation in the fine timing process can reach the magnitude order of ten to three, the algorithm precision is high, the multipath interference can be effectively resisted, and meanwhile the algorithm is low in complexity.
Description
technical field [0001] The invention relates to a timing synchronization scheme for an Orthogonal Frequency Division Multiplexing (OFDM) ultra-wideband (Ultra Wide Band, UWB) system that can resist multipath interference. For the 60GHz OFDM ultra-wideband system specified in the IEEE802.15.3c standard, the frame detection, coarse timing and fine timing schemes suitable for the system are designed by using the complementary correlation characteristics of the preamble Gray complementary sequence, so that it can be used in multipath fading channels. The symbol start position is detected with high precision for correct OFDM demodulation. Background technique [0002] Ultra-wideband wireless communication technology has the characteristics of low power spectral density, high transmission rate, and strong anti-multipath interference ability. It is mainly used in short-distance high-speed wireless communication, penetrating imaging, and measurement. The IEEE802.15.3c standard prop...
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Inventor 戈立军李春雨巨阿强杜亚梅
Owner TIANJIN POLYTECHNIC UNIV