11. The main objective of CELL in a cellular mobile system is
Higher bandwidth
Handoff
Frequency reuse
Simple modulation techniques
Answer.3. Frequency reuse
Explanation
Frequency reusing is the concept of using the same radio frequencies within a given area, that are separated by a considerable distance, with minimal interference, to establish communication.
Frequency reuse is the main objective of CELL in a cellular mobile system and it offers the following benefit:
Allows communications within the cell on a given frequency
Limits escaping power to adjacent cells
Allows re-use of frequencies in nearby cells
Uses the same frequency for multiple conversations
10 to 50 frequencies per cell.
12. Which of the following is a type of wireless communication?
LAN
WAN
PAN
All of the above
Answer.4. All of the above
Explanation
There are basically three different types of wireless networks – WAN, LAN, and PAN
Wireless Wide Area Networks (WWAN): WWANs are created through the use of mobile phone signals typically provided and maintained by specific mobile phone (cellular) service providers.
Wireless Local Area Network (WLAN): WLAN are wireless networks that use radio waves. The backbone network usually uses cables, with one or more wireless access points connecting the wireless users to the wired network.
Wireless Personal Area Network (WPAN): WPANs are short-range networks that use Bluetooth technology. They are commonly used to interconnect compatible devices near a central location, such as a desk.
13. Which of the following standard had not adopted digital TDMA for high capacity?
PDC
USDC
IS-95
GSM
Answer.3. IS-95
Explanation
Interim Standard 95 (IS-95) is a second-generation (2G) mobile telecommunications standard based on code division multiple access (CDM technology, which guarantees multiple access when sending voice and data between mobile phones and cell sites. IS-95 operates in the 800 MHz and 1900 MHz frequency bands.
Various proposed standards such as the GSM, US digital cellular (USD, and Pacific Digital Cellular (PD have adopted digital TDMA for high capacity. IS-95 does not use TDMA.
14. Identify the disadvantage of Bluetooth technologies from the given options
Used for voice and data transfer
Low power consumption
Affordable rates
Lower security
Answer.4. Lower security
Explanation
Bluetooth is a wireless technology that allows the exchange of data within a short distance.
Bluetooth uses short-wavelength UHF radio waves.
Bluetooth has low power consumption as Bluetooth modules can be embedded in handheld devices.
Usually, every network technology has some security built into it to prevent hackers from accessing your data without your permission. However, Bluetooth security is weak compared to Wi-Fi and other wireless data standards. A determined attacker can, for example, gain access to your wireless device through a Bluetooth connection, although he or she would have to be nearby for the attempt to work.
15. Consider the following statements for the public circuit-switching network:
1. Private branch exchange (PBX) is an application of circuit switching.
2. A switching center that directly supports subscribers is known as digital PBX.
3. The link between the subscriber and the network, is also referred to as the local loop.
Which of the above statements are correct?
1 and 2 only
1 and 3 only
1, 2 and 3
2 and 3 only
Answer.1. 1 and 2 only
Explanation
Circuit switching is a method of implementing a telecommunication network in which two network nodes establish a dedicated communication channel (circuit) through the network before the nodes may communicate.
A local loop is a wired connection from a telephone company’s central office with an integrated services digital network (ISDN) or digital subscriber line (DSL) (option 3 iswrong)
A private branch exchange is a telephone system within an enterprise that switches calls between users on local lines while enabling all users to share a certain number of external phone lines. PBXS can include network switching systems that accommodate analog phones into the enterprise’s digital PBX system. (option 1 iscorrect)
Private branch exchanges used analog technology originally. Today, PBXs use digital technology — digital signals are converted to analog for outside calls on the local loop using plain old telephone service (POTS). A switching center that directly supports subscribers is known as digital PBX.(option 2 is correct)
16. An instrument used to measure one’s location in terms of coordinates
GPS
ILS
FANs
GSM
Answer.1. GPS
Explanation
GPS, or the Global Positioning System, is a global navigation satellite system that provides location, velocity, and time synchronization. GPS receivers provide location in latitude, longitude, and altitude.
The satellite system consists of a constellation of 24 satellites in six Earth-centered orbital planes.
GPS is used to measure one’s location in terms of coordinates by measuring longitude and latitude.
GPS is made up of three different components, called segments, that work together to provide location information.
17. Which of the following is not an example of wireless communication?
Wi-Fi
Mobiles
Landline
Wireless Computer Parts
Answer.3. Landline
Explanation
The various types of wireless communication include radio broadcast (RF), infrared (IR), satellite, microwave, and Bluetooth. Mobile phones, GPS, Wi-Fi, and cordless telephones are devices that use wireless transmission to exchange data and information.
A landline is a telephone that transmits signals converted from audio data through physical media, such as wire or fiber optic cable, rather than through wireless transmission as is the case with mobile phones.
18. Which of the following measures the spectrum efficiency of a wireless system?
Spectral capacity
Channel capacity
Carrier capacity
Radio capacity
Answer.4. Radio capacity
Explanation
Spectrum efficiency describes the amount of data transmitted over a given spectrum or bandwidth with minimum transmission errors. Spectral efficiency in wireless communications speeds is affected by the number of users accessing the network concurrently.
Radio capacity is a parameter that measures the spectrum efficiency of a wireless system. This parameter is determined by the required carrier to interference ratio and the channel bandwidth.
19. Radio channel used for transmission of information from the base station to the mobile is called:
Reverse Channel
Page
Handoff
Forward Channel
Answer.4. Forward Channel
Explanation
Forward or downlink channels are used to transmit data from the base station to mobile devices.
Reverse or uplink channels are the channels used to transmit data from cell phones to base stations.
The forward control channel and the reverse control channel are responsible for call initiation and service requests.
During a call, a user’s call may be moved from one base station to another. The term “handoff” refers to the method of exchange.
20. Consider the following statements regarding the cellular system/network: