This article proposes a time/frequency synchronization algorithm in the multiple input multiple output （MIMO） systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code grou...This article proposes a time/frequency synchronization algorithm in the multiple input multiple output （MIMO） systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence. The synchronization algorithm is divided into four stages： 1） synchronization in time domain by signal autocorrelation; 2） synchronization in frequency domain by fast Fourier transform （FFT）; 3） multipath dissociation using coherent detection and fine time synchronization; 4） fine frequency offset estimation by phase rotation. As per the perfect complete generalized complementary orthogonal loosely synchronous code groups, the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The simulation results show that even in the multipath fast fading channel with low signal noise ratio （SNR）, the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.展开更多
Starting from the definition of Basic Complementary Coding (CC) Pairs, this paper presents a scheme of designing CC signals for practical applications. In comparison with the scheme based directly on the definition of...Starting from the definition of Basic Complementary Coding (CC) Pairs, this paper presents a scheme of designing CC signals for practical applications. In comparison with the scheme based directly on the definition of CC pairs, the present scheme can speed up the operation process for finding CC pairs by 24 × 2N/2 times when the number of coding units N>4.展开更多
A pulse-compression system composed of a complementary coding CC signal generator and a corresponding processor has been devel -oped. The working principle of using this system in seismic profiling at sea is described...A pulse-compression system composed of a complementary coding CC signal generator and a corresponding processor has been devel -oped. The working principle of using this system in seismic profiling at sea is described, and the effect of wave modulation on CC signal processing is examined in detail. Computer simulations have confirmed the effectiveness of applying this new approach to practical seismic profiling.展开更多
基金supported by the National Natural Science Foundation of China(90604035)
文摘This article proposes a time/frequency synchronization algorithm in the multiple input multiple output （MIMO） systems, in which the perfect complete generalized complementary orthogonal loosely synchronous code groups are used as the synchronization sequence. The synchronization algorithm is divided into four stages： 1） synchronization in time domain by signal autocorrelation; 2） synchronization in frequency domain by fast Fourier transform （FFT）; 3） multipath dissociation using coherent detection and fine time synchronization; 4） fine frequency offset estimation by phase rotation. As per the perfect complete generalized complementary orthogonal loosely synchronous code groups, the cross-correlation and out-of-phase auto-correlation for any relative shift between any two codes is always zero. This ideal property makes the time/frequency synchronization algorithm simple and efficient. The simulation results show that even in the multipath fast fading channel with low signal noise ratio （SNR）, the MIMO system can get synchronized both in the time domain and frequency domain with high stability and reliability.
基金The project supported by The National Natural Science Foundation of China
文摘Starting from the definition of Basic Complementary Coding (CC) Pairs, this paper presents a scheme of designing CC signals for practical applications. In comparison with the scheme based directly on the definition of CC pairs, the present scheme can speed up the operation process for finding CC pairs by 24 × 2N/2 times when the number of coding units N>4.
基金The project supported by National Natural Science Foundation of China
文摘A pulse-compression system composed of a complementary coding CC signal generator and a corresponding processor has been devel -oped. The working principle of using this system in seismic profiling at sea is described, and the effect of wave modulation on CC signal processing is examined in detail. Computer simulations have confirmed the effectiveness of applying this new approach to practical seismic profiling.
