1.
2.
Determine the maximum and minimum spectral frequencies received from a stationary GSM transmitter that has a center frequency of exactly 1950.000000 MHz, assuming that the receiver is traveling at speeds of: (a) 1 km/hr; (b) 5 km/hr; (c) 100 km/hr; and (d) 1000 km/hr.
3.
Given that the coherence bandwidth is approximated by Equation (5.39), show that a flat
fading channel occurs when *. *Hint: Note that * *is an RF bandwidth, and assume
that *, *is the reciprocal of the baseband signal bandwidth.
4
If a particular modulation provides suitable BER performance whenever
determine the smallest symbol period *, *(and thus the greatest symbol rate) that may be
sent through RF channels shown in Figure P5.6, without using an equalizer.
5.
If a baseband binary message with a bit rate is modulated by an RF carrier
using BPSK, answer the following:
(a) Find the range of values required for the rms delay spread of the channel such that the
received signal is a flat-fading signal.
(b) If the modulation carrier frequency is 5.8 GHz, what is the coherence time of the channel,
assuming a vehicle speed of 30 miles per hour?
(c) For your answer in (b), is the channel "fast" or "slow" fading?
(d) Given your answer in (b), how many bits are sent while the channel appears "static"?
6
For the power delay profiles in Figure P5.6, estimate the 90% correlation and 50% correlation
coherence bandwidths.
7.
Given that the probability density function of a Rayleigh distributed envelope is given by where is the variance, show that the cumulative distribution
function is given as . Find the percentage of time that a signal is
10 dB or more below the rms value for a Rayleigh fading signal.
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