If direct-sequence spread-spectrum (DS/SS) modulation is employed, the receiver must acquire the chip timing for incoming messages before these messages can be demodulated. If the system or network employs DS/SS multiple access, also known as code-division multiple access (CDMA), the acquisition process is more difficult because multiple messages are transmitted simultaneously and in the same f...

This paper demonstrates a way of achieving and maintaining sequence synchronization in multi-user direct sequence code division multiple access (DS-CDMA) based chaotic communication systems. Synchronization is achieved and maintained through the code acquisition and the code tracking phase, respectively. The performance of the proposed system is evaluated in the presence of additive white Gauss...

In this paper we propose two systems for achieving synchronization in asynchronous multi-user chaos-based DS-CDMA. For the first system, synchronization process is realized thanks to a binary code used as an additive pilot sequence to the spreaded signal. Gold sequences are used as pilot signals for the different users to accomplish the synchronization. For the second synchronization system, th...

L2C is the first modernised GPS signal for civilians, broadcast by the new generation of satellites, designated Block IIR-M. Currently three of these satellites (PRN-17, PRN-31 and PRN-12) have been declared operational by the Air Force Space Command at Schriever Air Force Base, Colorado. The structure of the L2C signal is designed such that it achieves a number of advantages over the GPS L1 si...

Because supply chains are complex systems prone to uncertainty, statistical analysis is a useful tool for capturing their dynamics. Using data on acquisition history and data from case study reports, we used regression analysis to predict backorder aging using National Item Identification Numbers (NIINs) as unique identifiers. More than 56,000 NIINs were identified and used in the analysis. Bay...

The recent growth in network usage has motivated the creation of new malicious code for various purposes, including economic and other malicious purposes. Currently, dozens of new malicious codes are created every day and this number is expected to increase in the coming years. Today’s signature-based anti-viruses and heuristic-based methods are accurate, but cannot detect new malicious code. R...

Conventionally, code acquisition with antenna array employs a correlator bank and the serial-search technique. Due to the inherent properties of correlators and serial search, mean acquisition time of the correlator-based approach is large, especially in strong interference environments. Recently, an adaptive-filtering approach has been applied to code acquisition. This method simultaneously pe...

In this paper, we analyze the code acquisition performance of a multicarrier direct-sequence spread spectrum (DS-SS) system in the presence of data modulation (i.e., no pilot) on multipath Rayleigh fading channels. The motivation of this analysis arises from the possibility of beneficially using multicarrier DS-SS in global positioning system (GPS) pseudolites, where unmodulated pilot is not av...