This set of Cognitive Radio Multiple Choice Questions & Answers (MCQs) focuses on “Environment Awareness – 3”.
1. ____ affects range accuracy adaption.
a) Resonance frequency
b) Bit rate
c) Symbol rate
Explanation: The amount of bandwidth available affects range accuracy adaption based on the optimisation technique utilised to choose parameter values. Resolution of bandwidth is another parameter that affects range accuracy adaption.
2. Two way ranging can resolve ____
a) amplitude difference
b) frequency difference
c) phase difference
d) amplitude and phase difference
Explanation: Synchronisation of oscillators of two transmitters may not be possible. In such a case, the measurement of path from the transmitter to receiver and from receiver to transmitter may be used to compensate for phase difference.
3. Time of arrival data from two base stations may provide ____ of a location.
a) position circle
c) peak circle
d) peak point
Explanation: Time of arrival is the time taken by a radio signal to cover the distance from a transmitter to a remote receiver. Time of arrival data from two substations offers the position circle of a location. Additional data from a third substation provides precise single point location.
4. Which among of the following may be employed to synchronise base station to local reference station?
a) Two signals of different frequency
b) Two signals of different phase
c) Four signals of different frequency
d) Four signals of different phase
Explanation: Synchronisation between base station and local reference station may be achieved by using accurate synchronous clocks, employing two signals of different frequency, or through measurement to or triggering from a common reference point.
5. Propagation loss is more in ____
a) lower carrier frequencies
b) higher carrier frequencies
c) lower bandwidth
d) higher bandwidth
Explanation:At higher carrier frequencies, higher propagation loss, and lower range and penetration are observed. The influence of weather and attenuation is more at higher carrier frequencies when compared to lower carrier frequencies.
6. Which among the following parameter of transceiver does not affect range accuracy?
b) Resolution of bandwidth
c) Transmission power level
d) Receiver power level
Explanation: The support exhibited by transceiver towards arbitrary bandwidth and resolution, and arbitrary transmission level can affect the performance of range accuracy adaption. These factors may be controlled by software defined radio capability of cognitive radio.
7. Which among on the following transceiver parameter may be used to improve range accuracy adaption?
a) Randomizing transmit power level
b) Decreasing the length of observation symbols
c) Increasing the length of observation symbols
d) Randomizing carrier frequencies
Explanation: The length of observation symbols is a transceiver parameter that affects range accuracy. Range accuracy improves by increasing the length of the observation symbols. However this introduces difficulties such as large overhead.
8. ____ exhibits the effect of channel distortion.
a) Equalization tap coefficient
b) Filter tap coefficient
c) Channel tap coefficient
d) Signal tap coefficient
Explanation: The channel tap coefficient is an environmental parameter that affects range accuracy. Channel tap coefficient exhibits the effect of channel distortion on a propagating signal. It is used in the final result computation of range accuracy at the receiver end.
9. Which among the following is an environmental parameter that affects ran accuracy?
a) Phase dependent coefficient of attenuation
b) Frequency dependent coefficient of attenuation
c) Phase dependent coefficient of channel
d) Frequency dependent coefficient of channel
Explanation: Frequency dependent coefficient of channel, path loss coefficient, and LOS/NLOS condition are some of the environmental parameters that affect range accuracy. The amount of influence shown by the frequency dependent coefficient of channel depend on the frequency dependent feature of the radio.
10. Multiuser interference is an example of external interference.
Explanation: Interference sources are of two types namely internal interference and external interference. Multiuser interference is an example of external interference. Inter-symbol interference is an example of internal interference.
Sanfoundry Global Education & Learning Series – Cognitive Radio.
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