Cognitive Radio Questions and Answers – Building CRA on SDR Architecture – 1

This set of Cognitive Radio Multiple Choice Questions & Answers (MCQs) focuses on “Building CRA on SDR Architecture – 1”.

1. Which among the following is not a component of hardware defined radio?
a) Demodulator
b) Antenna
c) Filters
d) Analog to digital converter
View Answer

Answer: d
Explanation: A typical hardware defined radio used as a frequency modulated/ amplitude modulated broadcast receiver consists of radio hardware such as antenna, filters, and demodulators. The primary function is the conversion of radio signals into audio signals.

2. Which among the following is an important characteristic of software radio?
a) Digital demodulation and analog filtering
b) Analog demodulation and digital filtering
c) Analog demodulation and filtering
d) Digital demodulation and filtering
View Answer

Answer: d
Explanation: The progression from hardware defined radio to software radio is marked by the introduction of the analog-to-digital converter and digital-to-analog converter in radio. An ideal software radio performs operations such as modulation, demodulation, frequency translation, and filtering digitally.

3. Which among the following represents the scale of spectrum band likely to be accessed by software defined radio?
a) 800 MHz – 900 MHz
b) 800 MHz – 850 MHz
c) 30 MHz – 2.5 GHz
d) 30 MHz – 250 MHz
View Answer

Answer: c
Explanation: The software defined radio desirably operates over a large range of frequencies that cover various bands of the spectrum. The radio should be capable of supporting various applications such as TV bands, air traffic control bands, industrial medical and scientific bands, etc. For example, 30 MHz – 2.5 GHz has a bandwidth of 2.47 GHz which is most suitable for the spectrum requirements of cognitive radio.

4. What is term used to refer to a handset with multiple single band RF chips?
a) Pocket radio
b) Multi-set radio
c) Slice radio
d) Fixed radio
View Answer

Answer: c
Explanation: The nature of RF devices such as antennas and filters normally support narrowband RF synthesis and intermediate frequency conversion. Wideband operation drives up cost and power consumption. One approach involves the installation of multiple single band RF chips in a handset. This handset is called as a slice radio or a Velcro radio.

5. Which among the following terms define the design space used to describe the development of software defined radio?
a) Digital access bandwidth and programmability
b) Digital access bandwidth and feasibility
c) Programmability and feasibility
d) Analog access bandwidth and feasibility
View Answer

Answer: a
Explanation: The software defined radio design space consists of a series of practical levels that represent the growth from hardware defined devices to ideal software defined radio. The design space is a plot between digital access bandwidth and programmability. The development of devices is due to increased availability and capability of resources.
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6. Which among the following is considered as the most power-efficient device?
c) DSP
d) GPP
View Answer

Answer: c
Explanation: Digital signal processors are simple to program, cost-effective, and power-efficient when compared to other devices such as ASIC and FGPA. However small memory and complicated instruction set architecture can increase the re-programmability cost of a digital signal processor.

7. How are the general purpose processors classified?
a) Based on memory
b) Based on bus
c) Based on interface
d) Based on instruction set
View Answer

Answer: d
Explanation: Complex Instruction Set Computer processor consists of a single instruction to carry out loading, evaluation, and storing operation. Reduced Instruction Set computer processor consists of a series of instructions to carry out loading, evaluation, and storing operation. The general purpose processors are commonly classified based on the instruction set.

8. Which among the following is not an API of the software communication architecture put forth by the SDR forum?
a) Physical
b) MAC
c) Security
d) Transport
View Answer

Answer: d
Explanation: An application programming interface is a computing interface that connects to a software component or a system. Components may access the API as per the terms presented by the API itself. In software communication architecture, API determines access to the physical layer, to the logical link layer, to the medium access control layer, to the security features, and to the input/output components.

9. Where does black processing occur in software communication architecture?
a) Black processing occurs between antenna and RF channel
b) Black processing occurs between antenna and RF conversion
c) Black processing occurs between RF conversion and INFOSEC module
d) Black processing occurs between antenna and INFOSEC module
View Answer

Answer: d
Explanation: Military radios assign the term ‘red’ for secret information. The term ‘black’ is used to refer to protected or encrypted information during transmission. Black processing generally takes place between the antenna and INFOSEC module, particularly the decryption process.

10. Which among the following is given as input to the system control unit?
a) Human-machine interface
b) Global framework
c) Fault management
d) Configuration management
View Answer

Answer: a
Explanation: System control resembles a framework. It contains a set of basic functions that are arranged in the form of a computational architecture in accordance with the norms of CORBA. It accepts input from the human-machine interface unit and overlooks the management of virtual channels, networks, security, etc.

11. Which among the following correspond to the point plotted in the graph?
Find the software defined radio from the given diagram
a) COTS Handset
b) Programmable radio
c) Software defined radio
d) Virtual radio
View Answer

Answer: c
Explanation: The graph depicts the design space of software defined radio. The plotted point corresponds to an ideal software defined radio. An ideal software radio is one in which every physical layer function is software defined. The radio must be flexible, multifunction, programmable, and easy to upgrade.

12. Constraint programming consists of variables, constraints, and domains.
a) True
b) False
View Answer

Answer: a
Explanation: In constraint programming, a problem is described as a mathematical equation. For example, ‘a’, ‘b’, ‘c’ are three whole numbers and the sum of ‘a’ and ‘b’ must be equal to ‘c’. Here ‘a’, ‘b’, and ‘c’ are the variables. The whole number corresponds to a domain. The sum of ‘a’ and ‘b’ must be equal to ‘c’ corresponds to a constraint.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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