In direct-sequence spread-spectrum systems, successful communications require phase synchronization of the incoming pseudonoise (PN) coded waveform with a locally generated replica at the receiver. It has been previously shown that sequential PN code acquisition schemes have the potential to achieve the best performance, but they are the least analyzed because of the analytical difficulties. Th...

In this paper, acquisition performance with adaptive pre-filtering is analyzed for a "coherent Paralperformance in a mobile fading channel. Under severe multiDath fading conditions. the P N code acauisition is difficult Y le1 matched-filter (MF) acquisition scheme with a reference filter (RF) in a multipath fading channel. Adaptive prefilterina is emoloved to reduce the effect of severe multipa...

This paper studies code synchronization in time hopping (TH) ultra wideband (UWB) systems. In TH UWB systems, narrow pulses based on Gaussian pulse are positioned in different locations in consecutive time frames. The location of each frame is defined by a spreading code. The receiver collects the energy of the pulses using the same spreading code. To be able to do that, it has to synchronize i...

Recently, a novel approach for PN code acquisition of direct sequence code division multipleaccess (DS-CDMA) systems in Rayleigh fading multipath channel was proposed in [1]. The authors considered a combination of adaptive thresholding constant false alarm rate (CFAR) and smart antennas to increase the system capacity and consequently enhance the detection performance. This paper considers sti...

|In this paper we evaluate and compare several algorithms based on eigenanalysis techniques for near-far resistant code acquisition and tracking, i.e., delay estimation in multiuser CDMA communication systems under di erent operating conditions. We show how the algorithms derived for the static case can easily be adapted to cope with time-varying situations. The proposed schemes are applicable ...

Canonical Hedgehog (HH) signaling leads to the regulation of the GLI code: the sum of all positive and negative functions of all GLI proteins. In humans, the three GLI factors encode context-dependent activities with GLI1 being mostly an activator and GLI3 often a repressor. Modulation of GLI activity occurs at multiple levels, including by co-factors and by direct modification of GLI structure...

In this paper we propose a serial-parallel correlator (SPC) for the purpose of PN code acquisition in a low earth orbit (LEO) satellite environment. To reduce the effect of severe Doppler in a LEO satellite channel, we combine the SPC with an FFT technique to combat the carrier frequency offset due to Doppler shift. By using the FFT technique we omit the need for an additional search over the f...