1. Consider the two-path example d = 2 km and the receiver at 1.5 km from the transmitter moving at velocity 60 km/h away from the transmitter. The carrier frequency is 900 MHz.

a. Plot in MATLAB the magnitudes of the taps of the discrete-time baseband channel at a fixed time t. Give a few plots for several bandwidths W so as to exhibit both flat and frequency-selective fading.

b. Plot the time variation of the phase and magnitude of a typical tap of the discrete- time baseband channel for a bandwidth where the channel is (approximately) flat and for a bandwidth where the channel is frequency-selective. How do the time-variations depend on the bandwidth? Explain.

2. For each tap of the discrete-time channel response, the Doppler spread is the range of Doppler shifts of the paths contributing to that tap. Give an example of an environment (i.e. location of reflectors/scatterers with respect to the location of the transmitter and the receiver) in which the Doppler spread is the same for different taps and an environment in which they are different.