Internal Assessment – I- Question Bank First Half of 2024
Chapter 1
1. Define the term Mobile Computing?
Mobile computing is the technology that allows users to connect and transmit data,
audio/voice, and video from one device to another without being tethered to a stationary
area with cabling and wires.
2. What are various applications of mobile Computing
Vehicles
– transmission of news, road condition, weather, music via DAB
– personal communication using GSM – position via GPS
Emergencies
– early transmission of patient data to the hospital, current status, first diagnosis
– replacement of a fixed infrastructure in case of earthquakes, hurricanes, fire etc.
– Disaster Management like crisis, floods, pandemic, ..
Travelling salesmen
– direct access to customer files stored in a central location
– consistent databases for all agents
– mobile office
Replacement of fixed networks
– remote sensors, e.g., weather, earth activities
– flexibility for trade shows
– LANs in historic buildings
Entertainment, education, ...
– outdoor Internet access
– ad-hoc networks for multi user games
3. List and explain Effects of signal propagation
Attenuation: Attenuation refers to the loss of signal strength as it travels through a
medium. In mobile computing, signals weaken over distance or as they pass through
obstacles (like buildings or trees), leading to reduced signal strength at the receiver. This
can impact the quality of the connection and may require the use of repeaters or
amplifiers to maintain effective communication ranges.
Doppler Effect: The Doppler Effect occurs when the frequency of a signal is altered in the
perspective of the receiver due to the relative motion between the transmitter and the receiver. In
mobile computing, this can affect the signal quality, especially in high-speed scenarios like in vehicles
or high-speed trains, requiring adaptive signal processing techniques to compensate for the variations.
Fading: Fading refers to variations in signal strength over time or space. It can be
caused by atmospheric conditions, multipath propagation, or the movement of objects
within the signal path. Fading can be fast or slow, depending on the speed of the
changes in signal strength, and it can significantly impact the reliability of wireless
communications. Techniques such as diversity reception and error correction coding
are used to mitigate fading.
Path Loss: Path loss is the reduction in power density of an electromagnetic wave as
it propagates through space. Path loss models help in predicting the signal strength at
a receiver's location based on the distance from the transmitter and the environment
(urban, suburban, rural). Understanding path loss is crucial for network design and
ensuring coverage across the intended area.
Shadowing: Shadowing occurs when obstacles block the direct path between a
transmitter and receiver, causing a shadow effect that results in a decrease in signal
strength. Unlike multipath, which might cause signal fluctuations over short distances,
shadowing can cause a signal to weaken over a larger area. Adaptive transmission
power and techniques to improve link reliability (like handover in cellular networks)
can help mitigate shadowing effects.
Absorption: Different materials absorb radio waves to varying degrees, converting
part of the signal energy into heat. This can significantly reduce the signal strength,
especially when it passes through dense materials like concrete or water.
Understanding the absorption characteristics of materials in the environment is
important for accurate network planning and optimization.
4. Explain features of Radio waves, Microwaves and Infrared wireless
communication medium used in mobile communication.
Certainly, here are the features of radio waves, microwaves, and infrared
waves, which are commonly used in wireless communication, including mobile
communication:
**1. Radio Waves:**
- Radio waves have a frequency range from 30 kHz to 300 GHz.
- They have long wavelengths, allowing for easy penetration through obstacles like
buildings and foliage.
- Used in AM and FM radio broadcasting, as well as cellular and Wi-Fi communication.
- Suitable for long-distance communication due to their low attenuation.
**2. Microwaves:**
- Microwaves have a frequency range between 300 MHz and 300 GHz.
- Shorter wavelengths compared to radio waves, enabling line-of-sight communication
and minimization of obstacles.
- Commonly used in satellite communication, microwave point-to-point links, and some
cellular backhaul connections.
- Limited by the line-of-sight requirement, often used for high-capacity, short to medium-
distance links.
**3. Infrared Waves:**
- Infrared waves have frequencies between 300 GHz and 400 THz.
- Shorter wavelengths than microwaves, often requiring a direct line of sight for
communication.
- Utilized in short-range communication systems, like infrared data transfer between
devices (IrDA).
- Limited to short distances due to the absorption by atmospheric gases and the need for a
clear line of sight.
5. List out terminology/concepts of Cellular System. State and Explain Frequency
Reuse with
6. Draw and explain different types of antennas example.
7. Differentiate between DSSS and
FHSS. 8 Differentiate between
TDM and FDM.
9 .Discus multiplexing and modulation techniques
used in GSM 10 What is Spread Spectrum? Explain
DSSS and FHSS.
Chapter 2
11. Draw and Explain GSM Architecture with suitable diagram and explain
function of various components of GSM architecture
12. List and explain numbers associated with
MS 13.Explain GSM frame structure and
different bursts 14.What is handover? Explain
GSM handover
15. What is localization and calling in GSM? Explain mobile Terminated call with
suitable diagram
16. Draw and explain GSM protocol architecture
