This set of Cognitive Radio Multiple Choice Questions & Answers (MCQs) focuses on “The xG Network Architecture – 1”.
1. Which among the following statements is true about the wireless network without xG architecture?
a) Existing wireless networks exhibit homogeneity in the spectrum policies and heterogeneity in the communication technologies
b) Existing wireless networks exhibit heterogeneity in the spectrum policies and homogeneity in the communication technologies
c) Existing wireless networks exhibit homogeneity in the spectrum policies and the communication technologies
d)Existing wireless networks exhibit heterogeneity in the spectrum policies and the communication technologies
Explanation: The currently available wireless networks express heterogeneity in both spectrum policies and communication technologies. For the effective incorporation of communication protocols, a clearly defined xG architecture model is required.
2. Which among the following statement is true about the primary network?
a) Primary network handles requests from xG users
b) Primary network uses the spectrum band periodically
c) Primary network has a dedicated spectrum band
d) Primary network competes for access to a spectrum band
Explanation: The currently available fixed infrastructure wireless network represents a primary network. It possesses the rights of a dedicated spectrum band. Cellular networks and TV broadcast networks are examples of the primary network.
3. Which among the following statement is false about the primary user?
a) Primary users are also known as licensed users
b) Primary users have exclusive right to use a spectrum band
c) Primary users are a part of the primary network
d) Primary users compete with the secondary users to access the spectrum band
Explanation: Primary users have exclusive rights to use a spectrum band. The primary base-station is responsible for monitoring and controlling the users accessing the spectrum band. Primary users have higher priority when compared to secondary users.
4. What are the units of the primary network?
a) Primary node and primary base-station
b) Primary user and primary base-station
c) Primary user and secondary user
d) Primary user and primary node
Explanation: Primary users are licensed users of the spectrum. Primary base-station refers to the fixed infrastructure network component with a spectrum license. The primary base-station contains legacy protocols and xG protocols for supporting communication through xG networks.
5. Which among the following is not a term used to refer to the xG network?
a) Cognitive radio network
b) Intelligent spectrum access network
c) Dynamic spectrum access network
d) Unlicensed network
Explanation: The xG network is also known as the secondary network, unlicensed network, cognitive radio network and dynamic spectrum access network. The xG does not have an exclusive right to use any spectrum band. xG networks aim to make use of temporarily unused spectrum bands.
6. What are the types of structures used to develop xG networks?
a) Infrastructure and ad hoc networks
b) Only infrastructure network
c) Only ad hoc networks
d) Centralised and distributed infrastructure network
Explanation: xG networks are made up of both infrastructure networks as well as ad hoc networks. xG users exist in a mixed spectrum environment and possess additional features to transmit on the licensed band. The path between the sender and the receiver depends on the type of network.
7. Which among the following connection is established by xG base-station?
a) Single hop for xG users
b) Multi-hop for xG users
c) Single hop for primary users
d) Multi-hop for primary users
Explanation: xG base-station is capable of providing single hop connection for xG users accessing the licensed portion of the spectrum. It is similar to a primary base-station with fixed network infrastructure network components however it has additional xG capabilities.
8. Which among the following statements is false about spectrum broker?
a) Spectrum broker is also known as scheduling server
b) Spectrum broker is connected to multiple networks
c) Spectrum broker bridges primary network and xG network
d) Spectrum broker is a central network entity
Explanation: Spectrum broker is responsible for sharing the spectrum resources among the different users of the xG network. It also works as an information manager supporting the combined operation of several xG networks. A spectrum broker is connected to each network in an area for coordinated operation.
9. What does the term spectrum heterogeneity mean in the context of xG architecture?
a) Licensed band and unlicensed band
b) UHF band and VHF band
c) Radio band and visible light band
d) Radio band and infrared band
Explanation: xG architecture exists in a mixed spectrum environment with licensed and unlicensed bands. Wideband access technology allows xG users to operate on both bands. xG users can communicate by using a base-station or by opting for a multi-hop connection.
10. Which among the following does not come under network heterogeneity?
a) xG network access
b) xG ad hoc access
c) Primary network access
d) xG spectrum access
Explanation: xG network access refers to the communication established via xG base-station on licensed and unlicensed spectrum band. xG ad hoc access refers to communication among xG users using an ad hoc connection on licensed and unlicensed spectrum band. Primary network access refers to the communication carried out using primary base-station on licensed spectrum band.
11. The primary user must contain legacy protocols and xG protocols for xG communication.
Explanation: Primary users do not undergo any modification to support xG base-stations and xG users. The operation of the primary user should not be hindered by unlicensed users. Similarly the xG users operating on the licensed band should not affect other primary users.
12. Which type of connection is depicted in the following diagram?
a) Centralised connection
b) Ad hoc connection
c) Fixed infrastructure connection
d) Single hop connection
Explanation: The connection depicted in the diagram is an xG ad hoc access connection. xG users may communicate among themselves using an ad hoc connection on licensed and unlicensed spectrum band. Ad hoc connection is typically a multihop connection. This type of connection is also known as xG connection without infrastructure.
Sanfoundry Global Education & Learning Series – Cognitive Radio.
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