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Full-Text Articles in Engineering

Channel Modeling For Vehicle-To-Vehicle Communications, David W. Matolak May 2008

Channel Modeling For Vehicle-To-Vehicle Communications, David W. Matolak

Faculty Publications

Physical layer channel modeling is critical for design and performance evaluation at multiple layers of the communications protocol stack. In this article we describe and provide results for modeling vehicle-to-vehicle (V2V) wireless channels. V2V settings produce some unique conditions, and due to these conditions, V2V channels often exhibit greater dynamics than many conventional channels and, in addition, can also exhibit more severe fading. Thus, new channel models are needed to characterize this setting in order to evaluate contending transmission schemes and aid in V2V communication system design. A brief review of key statistical channel parameters is provided. Then both analytical …


Spectrally Shaped Generalized Mc-Ds-Cdma With Dual Band Combining For Increased Diversity, Wenhui Xiong, David W. Matolak May 2008

Spectrally Shaped Generalized Mc-Ds-Cdma With Dual Band Combining For Increased Diversity, Wenhui Xiong, David W. Matolak

Faculty Publications

A new multicarrier spread spectrum modulation scheme is proposed in this paper. This scheme uses sinusoidal chip waveforms to shape the spectrum of each subcarrier of a multicarrier direct sequence spread spectrum (DS-SS) signal. As a result, each subcarrier has two distinct spectral lobes, one a lower sideband (LSB) and the other an upper sideband (USB). By properly selecting the parameters of the sinusoidal chip waveforms, the two sideband signals can be made to undergo independent fading in a dispersive fading channel. These two independently-faded sideband signals, when combined at the receiver, provide diversity gain to the system. Our analysis …


Influence Of Dispersion On Transport Of Tracer Through Unsaturated Porous Media, Thidarat Bunsri, Muttucumaru Sivakumar, Dharma Hagare Jan 2008

Influence Of Dispersion On Transport Of Tracer Through Unsaturated Porous Media, Thidarat Bunsri, Muttucumaru Sivakumar, Dharma Hagare

Faculty of Engineering - Papers (Archive)

The dispersion phenomenon has resulted from the various water flow magnitude and direction in porous media. The dissolved tracer tends to spread due to dispersion and then travel time of tracer through the porous media increases. In unsaturated porous media, dispersion coefficient varies with non-linear Darcy's velocity and the water content. These non-linear dispersions were observed in both the laboratory scale and soil columns (20cm). The unsaturated infiltration column and tracer tests have been used to interpret the relationships between Darcy's velocity and the water content together with the dispersion coefficient. However, the dispersivity coefficient cannot be measured directly; it …