Multi-Path Propagation
What causes multipath propagation in wireless communication?
A) Only direct line-of-sight transmission
B) Reflection, diffraction, and scattering
C) Only signal attenuation
D) Increase in transmission power
B) Reflection, diffraction, and scattering
What is the main purpose of a cellular network?
A) To provide wired communication
B) To enable wireless communication over a wide area
C) To replace fiber-optic networks
D) To limit mobile connectivity to a single location
B) To enable wireless communication over a wide area
What does MIMO stand for in wireless communication?
A) Multiple Input Multiple Output
B) Multi-user Integrated Mobile Operation
C) Mixed Interference Multi Output
D) Mobile Internet Multiple Operation
A) Multiple Input Multiple Output
Which modulation technique was primarily used in 1G networks?
A) Quadrature Amplitude Modulation (QAM)
B) Frequency Modulation (FM)
C) Frequency Shift Keying (FSK)
D) Frequency Division Multiple Access (FDMA) with analog FM
D) Frequency Division Multiple Access (FDMA) with analog FM
What is the carrier bandwidth of a single GSM channel?
A) 100 kHz
B) 200 kHz
C) 500 kHz
D) 1 MHz
B) 200 kHz
Which of the following is a major effect of multipath propagation?
A) Increased data transmission speed
B) Elimination of interference
C) Fading and Inter-Symbol Interference (ISI)
D) Reduced signal attenuation
C) Fading and Inter-Symbol Interference (ISI)
In a cellular network, what is a "cell"?
A) The battery of a mobile phone
B) A small geographical area covered by a base station
C) A type of mobile phone
D) A wireless access point in Wi-Fi networks
B) A small geographical area covered by a base station
What is the main advantage of combining MIMO with OFDM?
A) Increases power consumption
B) Reduces interference and improves spectral efficiency
C) Eliminates the need for antennas
D) Replaces frequency reuse techniques
B) Reduces interference and improves spectral efficiency
What was the main drawback of 2G networks that led to the development of 3G?
A) Inability to support voice calls
B) Limited data transfer rates for multimedia applications
C) Excessive power consumption
D) Requirement for high-frequency spectrum
B) Limited data transfer rates for multimedia applications
What is the primary purpose of the Location Area Identifier (LAI) in GSM networks?
A) To identify the frequency band used for communication
B) To track and manage the location of a mobile user within a specific region
C) To encrypt the communication between the mobile device and base station
D) To allocate time slots for data transmission
B) To track and manage the location of a mobile user within a specific region
Which technique helps reduce the effects of multipath fading in wireless communication?
A) Increasing transmission power
B) Spatial diversity (MIMO)
C) Using a single antenna system
D) Reducing the modulation order
B) Spatial diversity (MIMO)
What is the function of a Base Transceiver Station (BTS) in a cellular network?
A) To manufacture mobile phones
B) To control the entire mobile network
C) To transmit and receive radio signals to/from mobile devices
D) To provide internet services to computers
C) To transmit and receive radio signals to/from mobile devices
How does MIMO improve wireless communication performance?
A) By using multiple antennas to transmit and receive signals, increasing data rates and reliability
B) By limiting the number of users on the network
C) By reducing the power of transmitted signals
D) By using only one antenna for transmission
A) By using multiple antennas to transmit and receive signals, increasing data rates and reliability
In 3G networks, which multiple access technique was introduced to improve spectrum efficiency?
A) Frequency Division Duplex (FDD)
B) Orthogonal Frequency Division Multiplexing (OFDM)
C) Code Division Multiple Access (CDMA)
D) Time Division Duplex (TDD)
C) Code Division Multiple Access (CDMA)
In GSM, what role does the A3 algorithm serve in network security?
A) It encrypts voice and data transmission over the air interface
B) It authenticates the subscriber using the IMSI and a challenge-response mechanism
C) It controls the power level of mobile stations to reduce interference
D) It manages frequency hopping to avoid congestion
B) It authenticates the subscriber using the IMSI and a challenge-response mechanism
Which type of fading occurs due to small-scale multipath interference?
A) Large-scale fading
B) Doppler fading
C) Rayleigh fading
D) Path loss fading
C) Rayleigh fading
Which of the following techniques is used in cellular networks to allow multiple users to share the same frequency band efficiently?
A) Time Division Multiplexing (TDM)
B) Frequency Hopping Spread Spectrum (FHSS)
C) Multiple Access Techniques (FDMA, TDMA, CDMA, OFDMA)
D) Amplitude Modulation (AM)
C) Multiple Access Techniques (FDMA, TDMA, CDMA, OFDMA)
What role does Cyclic Prefix (CP) play in OFDM systems?
A) It improves bandwidth efficiency
B) It reduces Inter-Symbol Interference (ISI) by mitigating multipath effects
C) It eliminates the need for synchronization
D) It increases power transmission
B) It reduces Inter-Symbol Interference (ISI) by mitigating multipath effects
What fundamental shift in network architecture differentiates 4G LTE from 3G?
A) Transition from packet-switched to circuit-switched networks
B) Introduction of Time Division Multiplexing (TDM)
C) Use of a completely packet-switched, IP-based network for both voice and data
D) Elimination of base stations
C) Use of a completely packet-switched, IP-based network for both voice and data
In GSM, what is the function of the Abis interface?
A) It connects the Base Station Subsystem (BSS) to the Mobile Switching Center (MSC)
B) It provides communication between the Base Transceiver Station (BTS) and the Base Station Controller (BSC)
C) It manages the handover process between two different GSM networks
D) It is responsible for billing and subscriber management
B) It provides communication between the Base Transceiver Station (BTS) and the Base Station Controller (BSC)
In an OFDM system, which of the following techniques is used to combat Inter-Symbol Interference (ISI) caused by multipath propagation?
A) Frequency Hopping
B) Cyclic Prefix (CP)
C) Spread Spectrum
D) Beamforming
B) Cyclic Prefix (CP)
What is the main advantage of using frequency reuse in cellular networks?
A) It increases call drop rates
B) It reduces network congestion and increases capacity
C) It eliminates the need for base stations
D) It reduces battery consumption in mobile devices
B) It reduces network congestion and increases capacity
In MIMO-OFDM, what is the purpose of Spatial Multiplexing?
A) To increase data transmission rates by transmitting independent data streams over multiple antennas
B) To reduce power consumption by limiting the number of antennas
C) To convert analog signals into digital signals
D) To increase interference and noise
A) To increase data transmission rates by transmitting independent data streams over multiple antennas
Which of the following is a defining feature of 5G's New Radio (NR) compared to previous generations?
A) Exclusive reliance on low-frequency bands (<1 GHz)
B) Support for Ultra-Reliable Low Latency Communication (URLLC) and massive machine-type communication (mMTC)
C) Sole dependence on macro-cell base stations
D) Higher latency than 4G networks
B) Support for Ultra-Reliable Low Latency Communication (URLLC) and massive machine-type communication (mMTC)
How does Frequency Hopping improve GSM network performance?
A) It reduces co-channel interference by dynamically changing the carrier frequency
B) It increases the power of transmitted signals to enhance coverage
C) It allows multiple users to share the same frequency without interference
D) It eliminates the need for Base Station Controllers (BSCs)
A) It reduces co-channel interference by dynamically changing the carrier frequency