Illustrative Scenarios of Wireless Channels

α(θ, φ, f) is a property of...

a: The transmitter Explanation

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b: The channel Explanation

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c: The receiver Explanation

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d: None of the above Explanation

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What is coherence time?

a: The time it takes the signal to travel from the transmitter to receiver Explanation

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b: The time duration over which the channel impulse response remains strongly correlated Explanation

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c: The first time instant where the received signal has zero phase shift w.r.t. the original signal Explanation

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d: None of the above Explanation

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Coherence bandwidth is a property of...

a: The transmitted signal Explanation

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b: The channel Explanation

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c: The receiver architecture Explanation

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d: None of the above Explanation

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Higher delay implies which of the following?

a: Shorter coherence bandwidth Explanation

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b: Higher coherence bandwidth Explanation

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c: Higher coherence time Explanation

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d: Shorter coherence time Explanation

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How does a larger delay spread affect the coherence bandwidth?

a: It increases the coherence bandwidth Explanation

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b: It decreases the coherence bandwidth Explanation

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c: It does not affect the coherence bandwidth Explanation

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d: It makes the coherence bandwidth constant Explanation

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Which of the following is TRUE? The correlation of the channel impulse response over time is...

a: ..an exponentially decreasing function Explanation

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b: ..a sinusoid with monotonically decreasing envelope Explanation

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c: ..any arbitrary function depending on the velocity of the receiver Explanation

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d: ..a sinusoid with constant amplitude Explanation

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In a scenario where a direct path has a length of 150 meters and the reflected path has a length of 200 meters, calculate the delay spread.

a: 0.167 μs Explanation

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b: 1.67 ms Explanation

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c: 1.67 μs Explanation

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d: 0.167 ms Explanation

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Calculate the coherence bandwidth for the scenario including three paths arriving at receiver with delays of 1 μs, 3 μs and 7 μs

a: 1/2 MHz Explanation

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b: -1/2 MHz Explanation

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c: 1/6 MHz Explanation

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d: 1/4 MHz Explanation

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A mobile receiver is moving at 30 m/s directly towards a base station transmitting at a carrier frequency of 900 MHz. Using the Doppler shift equation fd = (v/c)*fc, what is the maximum Doppler shift? (Speed of light c = 3×10^8 m/s)

a: 90 Hz Explanation

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b: 30 Hz Explanation

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c: 120 Hz Explanation

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d: 900 Hz Explanation

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According to the exact two-ray ground reflection model approximation for large distances, received power Pr is proportional to (ht * hr)² / d⁴. If the heights of BOTH the transmitting (ht) and receiving (hr) antennas are doubled, how does the received signal power change?

a: It doubles (increases by a factor of 2) Explanation

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b: It increases by a factor of 4 Explanation

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c: It increases by a factor of 16 Explanation

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d: It remains the same Explanation

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