1. Small scale received power is ________ of average powers received in each multipath component.
a) Log
b) Exponential
c) Multiplication
d) Sum
Explanation:The average small received power is the sum of the average powers received in each multipath component. This is the case if transmitted signal is able to resolve the multipath.
2. The received power of a wideband signal fluctuates significantly when a receiver is moved about a local area.
a) True
b) False
Explanation: Amplitude of individual multipath components does not fluctuate widely in local area. Therefore, the received power of a wideband signal does not fluctuate significantly when a receiver is moved about a local area
3. Average power for a CW signal is _______ to average received power for a wideband signal in small scale region.
a) Equivalent
b) Two times
c) Four times
d) Ten times
Explanation: Average power for a CW signal is equivalent to average received power for a wideband signal in small scale region. This can occur when either the multipath phases are identically and independently distributed or when path amplitudes are uncorrelated.
4. The received local ensemble average power of wideband and narrowband signals are ________
a) Different
b) Equivalent
c) Not dependent
d) Double
Explanation: The received local ensemble average power of wideband and narrowband signals is equivalent. When the transmitted signal has bandwidth greater than bandwidth of the channel, the received power varies very little. However, if transmitted signal has very narrow bandwidth, large fluctuation occurs at receiver.
5.Power delay profile is represented as plots of __________ with respect to fixed time delay reference.
a) Relative received power
b) Frequency
c) Transmitted power
d) Relative power
Explanation: Power delay profiles are generally represented as plots of relative received power as a function of excess delay with respect to a fixed time delay reference. They are calculated by averaging instantaneous power delay profile measurements over a local area.
6. Which of the following is not a multipath channel parameter that can be determined from power delay profile?
a) Mean excess delay
b) RMS delay spread
c) Excess delay spread
d) Doppler spread
Explanation: The mean excess delay, excess delay spread and rms delay spread are some multipath channel parameters. They can be determined from a power delay profile. Doppler spread is a measure of spectral broadening caused by time rate of change of mobile radio channel.
7. The time dispersive properties of wideband multipath channel are quantified by ______ and _______
a) Mean excess delay, rms delay spread
b) Doppler spread, rms delay spread
c) Doppler spread, coherence time
d) Mean excess delay, Doppler spread
Explanation: The time dispersive properties of wide band multipath channels are most commonly quantified by their mean excess delay and rms delay spread. Coherence time characterizes the time varying nature of frequency dispersiveness of mobile radio channel in time domain
8. _______ is the square root of the second central moment of the power delay profile.
a) Mean excess delay
b) Rms delay spread
c) Excess delay spread
d) Coherence time
Explanation: The rms delay spread is the square root of the second central moment of the power delay profile. Many measurements are made at many local areas in order to determine a statistical range of multipath channel parameters for a mobile communication system over a large scale area
9. Which of the following is the first moment of the power delay profile?
a) Rms delay spread
b) Excess delay spread
c) Mean excess delay
d) Doppler spread
Explanation: Mean excess delay is the first moment of the power delay profile. It is defined from a single power delay profile which is temporal or spatial average of consecutive impulse response measurements collected and averaged over a local area.
10. What is the order of typical values of rms delay spread in outdoor mobile radio channels?
a) Microseconds
b) Nanoseconds
c) Seconds
d) Minutes
Explanation: Typical values of rms delay spread are on the order of microseconds in outdoor mobile radio channels. For indoor mobile radio channels, they are of the order of nanoseconds.