Given n relatively prime integers p1 < · · · < pn and an integer k < n, the Chinese Remainder Code, CRTp1,...,pn;k, has as its message space M = {0, . . . , ∏k i=1 pi − 1}, and encodes a message m ∈ M as the vector 〈m1, . . . ,mn〉, where mi = m(mod pi). The soft-decision decoding problem for the Chinese remainder code is given as input a vector of residues ~r = 〈r1, . . . , rn〉, a vector of wei...

This paper proposes noncoherent PN acquisition schemes that combine the hybrid structure, the RAKE structure, and the double/multiple-dwell technique in order to improve the performance in a frequency-selective fading channel. The hybrid structure reduces the acquisition time compared to a serial scheme. The RAKE structure enhances the received signal strength of a multipath faded signal, while...

Global positioning system (GPS) has been demonstrated to be a valid and efficient system for various space applications in low Earth orbit (LEO) and medium Earth orbit (MEO), such as for location determination and time synchronization. However, in highly elliptical and high Earth orbits (HEO), the number of existing space applications is much smaller because of the very weak power of the receiv...

Code Division Multiple Access (CDMA) is a spread spectrum technique that uses neither frequency channels nor time slots. With CDMA, the narrow band message (typically digitized voice data) is multiplied by a large bandwidth signal that is a pseudo random noise code (PN code). All users in a CDMA system use the same frequency band and transmit simultaneously. The transmitted signal is recovered ...

In this paper, we study a recently proposed multirate system, called wavelet based scale-code division multiple access (W/S-CDMA). W/S-CDMA depends on the code, time and scale orthogonality introduced by pseudo-noise (PN) sequences, and wavelets. In this system, the channel is partitioned into different scales, and each scale into time slots. In addition, the PN sequences are used in each scale...

Background Myocardial arterial spin labeling (ASL) is a non-contrast CMR technique for measuring myocardial blood flow (MBF), but has relatively low signal-to-physiological noise (PN). Therefore perfusion measurements are made over several averaged pixels within left ventricular (LV) segments and not individual pixels. Shorter image acquisition times using SENSE parallel imaging has been shown ...

Hyun Jung Kim et al. 273 Toward code division multiple access (CDMA) communications and data protection, we propose and analyze pseudorandom noise (PN) sequences generated from a 2-dimensional array structure of shift-registers. For any positive integers m and n, we construct PN sequences of period 2–1 using an m×n array of registers and show that we can generate all shifted PN sequences as req...

Block processing Fast Fourier Transform (FFT) algorithms have been developed to do signal acquisition for the new CM and CL civilian codes that will appear on the L2 GPS frequency once the Block IIR-M satellites are launched. These algorithms have been developed to aid in the acquisition of weak GPS signals. FFT block processing can be used to significantly reduce the computational burden cause...

This paper presents a performance analysis of a novel searcher designed for array antenna in terms of average acquisition time as well as detection and false alarm probability. It has been shown that proposed searcher significantly reduces the acquisition time compared to the conventional searcher, which does not exploit the merit of array antenna structure. Due to the shortened acquisition tim...

Two classes of nonlinear feedforward logic (NLFFL) pseudonoise (PN) code generators based on the use of AND and majority logic (ML) gates are compared. Crosscorrelation and code-division multiple-access (CDMA) properties of properly designed NLFFL sequences are found to be comparable with the properties of well-known linear PN codes. It is determined that code design employing ML gates with an ...