Antennas and propagation for wireless communication systems

Simon Saunders, Alejandro Aragón-Zavala

Chapter 16 Overcoming Narrowband Fading via Diversity - all with Video Answers

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Chapter Questions

Problem 1

Calculate the correlation coefficient for a polarisation diversity system with two antennas polarised at $\pm 45^{\circ}$ to the vertical, with a cross-polar discrimination from the environment of $6 \mathrm{~dB}$ when the mobile is at $30^{\circ}$ to the boresight direction.

Mayukh Banik

Numerade Educator

Problem 2

Calculate the time separation required for two signals to achieve a high degree of time diversity in a classical Rayleigh channel at $900 \mathrm{MHz}$ with a mobile speed of $10 \mathrm{~km} \mathrm{~h}^{-1}$.

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Problem 3

Given a two-branch selection-combining system operated with independent Rayleigh fading, estimate then calculate the diversity gain for a fade probability of $10^{-6}$.

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Problem 4

Devise an algorithm for a switched combiner which reduces the amount of chatter shown in Figure 16.15.

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Problem 5

Derive an expression for the instantaneous SNR at the output of an equal gain combiner with three branches in terms of the instantaneous SNR at the inputs to each of the branches.

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Problem 6

Explain why an equal gain combiner must co-phase signals before combining them. If two branches are independently Rayleigh distributed with equal mean power $P$, what is the distribution of the combined signal without co-phasing? What is the diversity gain in this case? What is the effective diversity order?

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Problem 7

Discuss the advantages of using polarisation diversity over other diversity techniques.

Joseph Fritchman

Numerade Educator