An eficient timing synchronization technique for a low complexdp FFT based multi-carrier direct sequence spread spectrum IF/baseband transceiver is presented. The timing synchronization control loop consists of a robust acquisition loop and a tracking loop that eliminates the timing phase ofiset caused by the transmission delay, sampiing error, and channel noise. The acquisition loop reduces th...

Distributed intelligence is set to revolutionise the interface between humans and the surrounding environment. Smart objects will become more and more commonplace in the home of the next decade, in a dynamic network of distributed intelligent elements. One of the most important steps yet to be addressed in this vision is a positioning system able to locate people and objects and allow them to i...

A second example is representative of a complex antenna structure. An RCDLA, introduced by [5] and shown in Fig. 1, is analysed close to a homogeneous lossy dielectric sphere of radius R = 0.10m with relative permittivity E, = 50 and specific conductivity o = 1.3Sirn at f = 925MHz. The distance between the sphere and case is 0.02m, and the cover plate of the case is 0.04111 above the plane 8 = ...

Spread spectrum forms an important aspect of digital communication technology where the message signal is transmitted over a channel having bandwidth much greater than required. Direct Sequence Spread Spectrum (DSSS) belongs to the category of spread spectrum methods and forms an important part in mobile communications. The objective of this paper is to investigate the FIR optimal, Wiener and l...

Direct-sequence spread spectrum is used for underwater acoustic communications between nodes, at least one of which is moving. At-sea data show that the phase change due to source motion is significant: The differential phase between two adjacent symbols is often larger than the phase difference between symbols. This poses a challenge to phase-detection based receiver algorithms when the source...

Many recent standards in telecommunications field are based on CDMA spread spectrum transmissions. In this paper, we describe a methodology for top-down design, modeling, and simulation of CDMA transmitter system using hardware description language VHDL-AMS. Details of VHDL-AMS implementation for each elementary block are shown. This paper together with the developed library of CDMA transmitter...

Abstract Single-carrier (SC) transmission is an appropriate transmission scheme for uplink transmission because of its low peak-to-average power ratio (PAPR). Spread spectrum (SS) transmission achieves higher frequency diversity gain and hence improves the bit error rate (BER) performance. The authors have recently proposed SC with frequency-domain spread spectrum (SC-FDSS) transmission with or...

This brief studies the performance of selected chaos-based systems which share their frequency bands with conventional spread-spectrum systems. Such a scenario may occur in normal practice when chaos-based systems are introduced while the conventional systems are still in operation. The particular chaos-based systems under study are the coherent chaos-shift-keying system and the noncoherent dif...

This paper proposes a new approach in chirp modulation spread spectrum (CMSS). A good selection of the parameters of the linear chirps, which are used in chirp modulation, combined with antipodal signaling significantly reduces the multiple access interference (MAI) even for small time-bandwidth products. This makes such systems attractive for efficient spread spectrum multiple access. Equal en...

Spread-spectrum packet radio networks are currently being considered for use in the factory of the future. These networks have the resistance to fading and the inherent multiple access capability that are necessary to interconnect the Autonomous Guided Vehicles (AGVs) and other mobile machines and personnel that will be used in the future factory. This paper reports on progress in the design an...