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Chapter 3 Channel Modeling

Large-scale effects Small-scale effects Undesired signals (noise and interfering

signals)

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3.3 Large-Scale Channel Modeling

The signal attenuation with distance (Path Loss) 3.3.1 Free-space path loss modeling: the Friis

Transmission Formula(功率传播方程 )Flux density(流量密度 )

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Conclusion: The path loss, or more accurately the spreading loss, in free-space is not frequency dependent.

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3.3.2 Path Loss Modeling for Non-Free-Space Environments Average Path Loss of a Narrow band system

For UWB, n is almost constant with frequency.

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Small-scale channel modeling

Include the small-scale fading in a local environment as well as the distortion of the transmitted waveform due to multipath.

Statistical modeling needed for proper receiver design. (evaluation of the receiver, diversity mechanisms, and potential multiple antenna applications)

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Statistical modeling of the channel impulse response

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Saleh-Valenzuela Model

L is the number of paths per cluster

and K is the number of clusters. The basic assumption behind this model is that

the multipath components arrive in clusters. The cluster arrivals are described by a Poisson

process.

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Other models

Delta-K model Single Poisson model Modified Poisson model Split-Poisson model

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Chapter4 Antennas

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Resonant monopole

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Archimedean Spiral- a frequency independent antenna

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TEM Horn- a UWB antenna

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summary

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