1. Which regulatory body is responsible for allocating spectrum for millimeter-wave communications?
a) Federal Communications Commission (FCC)
b) International Telecommunication Union (ITU)
c) European Telecommunications Standards Institute (ETSI)
d) Institute of Electrical and Electronics Engineers (IEEE)
Answer: a) Federal Communications Commission (FCC)
Explanation: The FCC in the United States is responsible for regulating and allocating spectrum, including for millimeter-wave communications.
2. What is the primary advantage of beam-forming in millimeter-wave communications?
a) Increased spectral efficiency
b) Reduced interference
c) Longer communication range
d) Lower power consumption
Answer: a) Increased spectral efficiency
Explanation: Beam-forming allows for more precise targeting of signals, which increases spectral efficiency by focusing energy in specific directions.
3. Which technique is used for managing interference in millimeter-wave communications?
a) Beam-steering
b) Frequency hopping
c) Spatial modulation
d) Pilot contamination
Answer: d) Pilot contamination
Explanation: Pilot contamination refers to the interference caused by pilots (reference signals) from neighboring cells in Massive MIMO systems, which needs to be managed effectively.
4. In Massive MIMO, what does CSI stand for?
a) Cell Signal Interference
b) Channel State Information
c) Carrier Sense Indicator
d) Coordinated Spatial Interference
Answer: b) Channel State Information
Explanation: CSI is crucial in Massive MIMO for optimizing beamforming and spatial multiplexing, as it provides knowledge of the channel conditions.
5. Which propagation channel models are commonly used for Massive MIMO systems?
a) Rayleigh fading
b) Path loss model
c) Free-space path loss
d) 3GPP urban macro
Answer: d) 3GPP urban macro
Explanation: The 3GPP urban macro model is frequently used for modeling propagation in Massive MIMO systems, particularly in urban environments.
6. What is the main challenge associated with Massive MIMO with Imperfect CSI?
a) Increased hardware complexity
b) Pilot contamination
c) Channel estimation errors
d) Limited bandwidth
Answer: c) Channel estimation errors
Explanation: Imperfect Channel State Information (CSI) leads to errors in estimating the channel state, affecting the performance of beamforming and interference management.
7. Which physical layer technique combines modulation and spatial processing in millimeter-wave communications?
a) OFDM
b) MIMO
c) Spatial modulation
d) Beamforming
Answer: c) Spatial modulation
Explanation: Spatial modulation utilizes both spatial processing (multiple antennas) and modulation to transmit data efficiently in millimeter-wave communications.
8. What is a characteristic feature of Multi-Cell Massive MIMO systems?
a) Single-cell coverage
b) Reduced interference
c) Increased pilot contamination
d) Limited scalability
Answer: b) Reduced interference
Explanation: Multi-Cell Massive MIMO systems aim to reduce interference by coordinating transmission and reception across multiple cells.
9. Which deployment scenario is particularly suitable for millimeter-wave communications?
a) Rural areas
b) Indoor environments
c) Underground tunnels
d) Submarine communications
Answer: b) Indoor environments
Explanation: Millimeter-wave communications are well-suited for indoor environments due to their high data rates and ability to penetrate obstacles like walls.
10. What is the primary benefit of using Massive MIMO in terms of mobility management?
a) Lower latency
b) Higher throughput
c) Seamless handovers
d) Reduced packet loss
Answer: c) Seamless handovers
Explanation: Massive MIMO’s ability to adaptively adjust beamforming and antenna patterns facilitates seamless handovers between base stations, improving mobility management.