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Quiz Type

Practice

Subject

Computer Science

Level

Level 600

Questions

20 questions

Created By

Akotia Louis

Quick Rules

Time limit: 20 minutes
Multiple attempts are not allowed
All questions must be answered to submit

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Question 1 of 20

Question 1

Multiple choice

Which of the following metrics is NOT used in the handoff decision process?

Call dropping probability

Call completion probability

Signal-to-noise ratio

Correct

Interruption duration

Explanation

Signal-to-noise ratio is not specifically mentioned as a metric in the handoff decision process, while the others are directly listed.

Question 2

Multiple choice

In the context of handoffs, what characterizes a hard handover?

Connections to both BSs are sustained simultaneously

The connection to the previous BS is maintained until the new connection is established

The connection to the previous point of attachment is broken before connecting to the new one

Correct

The mobile unit initiates the handover request

Explanation

A hard handover involves breaking the connection to the previous base station before establishing a connection to the new one.

Question 3

Multiple choice

Which term describes the probability that a handoff will fail during a call?

Handoff blocking probability

Call completion probability

Probability of unsuccessful handoff

Correct

Call dropping probability

Explanation

The probability of unsuccessful handoff specifically refers to the likelihood of a handoff failing during an ongoing call.

Question 4

Multiple choice

In which scenario does upward handover occur?

From a larger network with lower bandwidth to a smaller network

From a smaller network with substantial bandwidth to a larger network

Correct

When moving from one BS with low signal strength to another with higher strength

When a mobile chooses its own BS for handover

Explanation

Upward handover occurs when the mobile unit moves from a smaller network with more available bandwidth to a larger network.

Question 5

Multiple choice

What is the significance of specifying an optimum signal level for handoffs?

It increases the likelihood of dropped calls

It ensures that unnecessary handoffs do not occur

Correct

It reduces the average signal strength needed for calls

It simplifies the connection process for new BSs

Explanation

Specifying an optimum signal level helps avoid unnecessary handoffs while maintaining call quality.

Question 6

Multiple choice

What type of interference is caused by frequency reuse in cellular systems?

Adjacent channel interference

Co-channel interference

Correct

Multipath interference

Power level interference

Explanation

Co-channel interference arises when multiple cells reuse the same frequency within a coverage area.

Question 7

Multiple choice

What does the acronym GOS stand for in cellular systems?

Grade of Service

Correct

General Operational System

Group of Subsystems

Geographic Operational Standards

Explanation

GOS stands for Grade of Service, a measure of the likelihood that a user will be able to access the system.

Question 8

Multiple choice

Which antenna arrangement can reduce co-channel interference by ensuring fewer interferers reach a mobile unit?

Directional antenna

Correct

Omni-directional antenna

Single cell antenna

Broadband antenna

Explanation

Directional antennas can help focus the signal and minimize interference from unwanted sources.

Question 9

Multiple choice

What is the main challenge posed by cell dragging in microcell systems?

Sudden loss of signaled handoff

Maintaining signal strength while out of range

Correct

Frequent dropping of calls due to interference

Excessively long signal duration times

Explanation

Cell dragging occurs when users continue to receive strong signals even as they move outside of the desired coverage area.

Question 10

Multiple choice

How can power control benefit cellular systems?

By maintaining maximum power at all times

By allowing the use of non-directional antennas

By ensuring each mobile transmits the minimum necessary power

Correct

By eliminating the need for handoffs entirely

Explanation

Power control reduces the power level transmitted by each subscriber unit to maintain signal quality while conserving battery.

Question 11

Multiple choice

What does the SIR formula measure in the context of co-channel interference?

Signal-to-Noise Ratio

Signal to Interference Ratio

Correct

Signal Input Range

System Integration Rate

Explanation

The SIR (Signal to Interference Ratio) evaluates the balance between desired signal strength and interfered signal strength.

Question 12

Multiple choice

What is the primary importance of monitoring signal levels over time before initiating a handoff?

To increase call quality at all times

To avoid unnecessary handing off during momentary fading

Correct

To maximize the amount of dropped calls

To reduce handoff delays

Explanation

Monitoring signal levels helps to determine if the drop is temporary or if the mobile is genuinely moving away from the BS.

Question 13

Multiple choice

What type of cell is used primarily to connect personal equipment over short distances?

Macrocells

Femtocells

Correct

Microcells

Megacells

Explanation

Femtocells are small cell units designed for short-range connectivity, typically used in personal settings.

Question 14

Multiple choice

What is a key characteristic of soft handover?

The mobile breaks the previous connection before making a new one

The mobile connects to the new base station before breaking the previous connection

Correct

Only network-based decisions are permitted

Interruption during the handoff is inevitable

Explanation

Soft handover allows for connection to be made to a new BS prior to breaking the previous connection, reducing disruption.

Question 15

Multiple choice

What is the trade-off associated with using a sectorized antenna in cellular systems?

Improved coverage but lower user capacity

Correct

Increased interference but higher call quality

Higher transmit power with reduced fading

Elimination of handoff delays

Explanation

While sectorized antennas can improve signal quality and reduce interference, they also limit the number of users due to fewer available frequencies.

Question 16

Multiple choice

What limits the performance of cellular radio systems greatly due to its nature in urban environments?

Frequency modulation

Interference

Correct

Signal fading

Multiple access schemes

Explanation

Interference is recognized as a major limiting factor in urban cellular systems due to the high density and activity in these environments.

Question 17

Multiple choice

When deciding the handoff, why is it crucial to differentiate between temporary signal fading and actual movement away from the BS?

To maximize signal strength before handoff

To decide when to initiate a handoff correctly

Correct

To reduce overall network traffic

To improve call duration statistics

Explanation

Identifying whether the signal drop is temporary or due to movement ensures that handoffs are made effectively, preserving call integrity.

Question 18

Multiple choice

In calculating the signal-to-CCI ratio, what is required to derive the interfering cell’s power effect?

The number of users in a cell

Distance of the interfering cell from the mobile

Correct

Location of antennas within the cell

Channel frequency allocated to the mobile

Explanation

The distance between the mobile unit and the interfering cell is essential to gauge how much that interference affects the signal received.

Question 19

Multiple choice

In the context of handoff in wireless systems, which type of handoff occurs when a connection to the previous point of attachment is broken before a connection to the new point of attachment is made?

Mobile-assisted handover

Soft handover

Network-based handover

Hard handover

Correct

Explanation

A hard handover takes place when the existing connection is terminated before establishing a new connection, which is critical in managing signal quality during transitions between cells.

Question 20

Multiple choice

Which strategy aims to minimize interference in cellular networks by monitoring the signal levels before initiating a handoff?

Immediately transferring calls upon signal drop

Using an aggressive handoff strategy without monitoring

Initiating handoffs based solely on user feedback

Monitoring signal levels over time before handoff

Correct

Explanation

Monitoring signal levels over a period helps to confirm that a drop in signal level is due to movement away from the serving base station and not just momentary fading, ensuring smoother handoff procedures.