Question

Which of the reception problems below that is not due to multipath?

(a) Delayed spreading

(b) Rayleigh fading

(c) Random Doppler shift

(d) Slow fading

This question was posed to me during a job interview.

Query is from Rayleigh and Ricean Distribution topic in chapter Mobile Radio Propagation: Small – Scale Fading and Multipath of Wireless/Mobile

Answer 1

Correct option is (d) Slow fading

To elaborate: Slow fading arises when the coherence time of the channel is large relative to the delay requirement of the application. Slow fading is caused by events such as shadowing, where a large obstruction such as a hill or large building obscures the main signal path between the transmitter and the receiver.