The use of differentially coherent combining is proposed to improve the performance of a double-dwell acquisition system. The differentially coherent combining is employed to increase the reliability of a decision in the verification stage. The mean acquisition time performance of the acquisition scheme with the proposed combining scheme is analyzed in a Rayleigh fading channel, and compared wi...

| In this paper, the performance of some code acquisition schemes are studied in the downlink of DS-CDMA systems. The conventional matched lter, the minimum variance method, the MUSIC algorithms and the eigenvector method based delay acquisition schemes are studied in a frequency-selective fading channel. The three last algorithms are based on diierent estimation schemes for the inverse of the ...

In this paper, we consider the noncoherent code acquisition problem using sequential schemes. To alleviate the computational complexity of the maximum likelihood method, simplified schemes are proposed and analyzed for the truncated sequential probability ratio test. The performance of the simplified and original schemes are compared in additive white Gaussian noise and slowly varying fading ch...

An improved technique with a fractional sampling based on two samples per chip, according to the Nyquist criterion, has been employed by the authors to enhance the performance in the code synchronization of UMTS (or W-CDMA) systems. In this paper, we investigate on the theoretical rationale of such a promising behavior. The performance is analyzed for several wireless channels, in the presence ...

In this paper, signed-rank based nonparametric detectors are used for pseudonoise (PN) code acquisition in direct sequence spread spectrum (DS/SS) systems. We first derive the locally optimum rank (LOR) detector, and then propose a locally suboptimum rank (LSR) detector and a modified signed-rank (MSR) detector using approximate score functions. We compare the single-dwell scheme without the ve...

In this letter the antenna array based GNSS signal acquisition is proposed by firstly projecting the input signal vector onto the noise subspace which is orthogonal to interference subspace for strong interferences suppression. Then, considering that the projection matrix is rank-deficient, we propose to apply forward spatial smoothing to decorrelation of the coherent interference-free signal v...

We propose a novel color code, Hamming color code, designed for rapid 3D shape acquisition using structured light projection. The Hamming color code has several properties which are desirable for practical 3D acquisition as follows. First, the Hamming distance of adjacent colors is always 1, which makes the color detection robust to color blending due to defocusing, subsurface scattering, or ch...

In this paper, the problem of coherently extending the integration time for the acquisition of new Global Navigation Satellite System (GNSS) signals is addressed. Unlike the acquisition of legacy GNSS signals, the presence of secondary codes allows the polarity of the transmitted signal to change each primary code period. These polarity changes have to be recovered and symbol combinations have ...

In most previously reported studies on pseudonoise (PN) code acquisition, independent additive noises have been assumed in various noise environments. The use of an independent observation model may cause considerable performance degradation in modern high datarate communication systems. In these studies, only additive noise model is considered. In this paper, a new detector for PN code acquisi...