Multicarrier Code Division Multiple Access Schemes (MC-CDMA) have been recently introduced in existing CDMA based systems to improve security, data transmission rate and to minimize Inter Symbol Interference (ISI). CDMA experiences severe multipath fading which badly affects its performance. By transmitting identical narrowband DirectSequence (DS) waveforms using frequency diversity, in paralle...

In this paper, we investigate the diversity, capacity and complexity issues of cooperative Zero-Padding (ZP)-Orthogonal Frequency Division Multiplexing (OFDM) communication. We consider cooperative ZP-OFDM communication over a multipath Rayleigh channel and with multiple Carrier Frequency Offsets (CFOs) existing at different relays. We use a cooperative tall Toeplitz scheme to achieve full coop...

The capacity of future wireless networks must be increased to accommodate more demanding wireless devices and applications. Network coding at the physical layer, although originally applied in wired networks, can be used to exploit the broadcasting capability of the wireless channel to increase network capacity. A wireless channel is characterized by multipath fading which produces interference...

An experimental analysis to evaluate the practical suitability of the Underwater Acoustic (UWA) communication scheme is the major aim of this study. Oceanic channel imposes two major challenges (i.e., multipath propagation and Doppler effects) for underwater acoustic communication. Being fastest possible underwater information exchanger, OFDM is considered as the most viable option for mitigati...

A space-time processing scheme is proposed for TDMA based cellular/PCS communications that cancels co-channel interference while simultaneously equalizing the desired signal. This is achieved through processing of a training signal designed from a PN code. At the receiver, the symbol waveform is built up above the noise and interference through correlation with a sampled waveform designed to ex...

The two key limiting factors facing wireless systems today are multipath interference and multiuser interference. In this context, a challenging signal processing problem is the joint space-time equalization of multiple digital signals transmitted over multipath channels. We propose a blind approach that does not use training sets to estimate the transmitted signals and the space-time channel. ...

Reliable positioning of cellular users in a mobile environment requires accurate resolving of overlapping multipath components. However, this task is difficult due to fast channel fading conditions and data ill-conditioning, which limit the performance of leastsquares-based techniques. This paper develops two overlapping multipath resolving methods (adaptive and nonadaptive), and shows how the ...

AbsImcf-This paper describes a new system architecture for high data rate digital acoustic communication over a shallow underwater channel that is subject to severe Doppler and time delay spread. The method uses high-resolution channel eharacterization in the time and frequency domains to resolve the main multipath components. This is followed by successive interference cancellation using the D...

This paper presents a novel receiver design from signal processing viewpoint for direct-sequence code-division multiple access (DS-CDMA) systems under multipath fading channels. A robust adaptive decision-feedback equalizer (DFE) is developed by using optimal filtering technique via minimizing the mean-square error (MSE). The multipath fading channels are modeled as tapped-delay-line filters, a...

This paper studies the ergodic capacity of wideband multipath channels with limited feedback. Our work builds on recent results that have established the possibility of significant capacity gains in the wideband/low-SNR regime when there is perfect channel state information (CSI) at the transmitter. Furthermore, the perfect CSI benchmark gain can be obtained with the feedback of just one bit pe...