Topic in Computer Networks & Cloud Computing
Wireless networks connect devices using radio, microwave or infrared signals instead of cables, with IEEE 802.11 Wi-Fi the most common local example. Questions compare 802.11 variants such as a, b, g, n, ac and ax, the 2.4 GHz and 5 GHz bands, and infrastructure mode against ad-hoc mode. Protocol details include beacon frames, scanning, authentication and association, and CSMA/CA with RTS/CTS to handle hidden and exposed terminals. Security questions trace the move from WEP to WPA, WPA2 with AES-CCMP, and WPA3. Bluetooth, mesh networks, cellular generations and satellite latency caused by long propagation distance are also covered.
Below are 30 practice questions from a pool of 210 Wireless Networks MCQs, one of 10 topics in Computer Networks & Cloud Computing. Each shows the correct answer with an explanation; when you are ready, take a timed quiz to test recall under exam conditions.
Each question below shows the correct answer with a full explanation. Use these to build conceptual understanding before attempting a timed quiz.
Q1. What frequency bands does IEEE 802.11n (Wi-Fi 4) support?
IEEE 802.11n (Wi-Fi 4) supports both 2.4 GHz and 5 GHz bands, offering improved speeds through MIMO technology and channel bonding.
Q2. What does Wi-Fi stand for?
Wi-Fi is a brand name created by the Wi-Fi Alliance for IEEE 802.11 wireless networking. It is not an acronym, though it is often incorrectly said to stand for Wireless Fidelity.
Q3. Which IEEE standard defines Wi-Fi?
IEEE 802.11 is the standard for wireless LANs (Wi-Fi). 802.3 is Ethernet, 802.15 is Bluetooth/WPAN, and 802.16 is WiMAX.
Q4. What does SSID stand for in wireless networking?
SSID (Service Set Identifier) is the name of a wireless network that clients use to identify and connect to it.
Q5. What is the hidden station problem in wireless networks?
The hidden station problem occurs when two stations are out of range of each other but both in range of the access point. They cannot detect each other's transmissions, leading to collisions.
Q6. Which wireless technology is designed for very short-range communication used in contactless payments?
NFC (Near Field Communication) is designed for very short-range communication (about 4 cm), used in contactless payments, access cards, and data exchange.
Q7. Which generation of cellular networks introduced mobile broadband data?
3G introduced mobile broadband data services with speeds sufficient for internet browsing and video calling. 1G was analog voice, 2G was digital voice with basic data.
Q8. What is an Access Point (AP) in a wireless network?
An Access Point (AP) is a networking device that connects wireless client devices to a wired network, acting as a bridge between the two.
Q9. Why does Wi-Fi use CSMA/CA instead of CSMA/CD?
In wireless, a station cannot reliably detect collisions while transmitting because its own signal overwhelms incoming signals. CSMA/CA uses collision avoidance techniques instead.
Q10. What frequency band does Bluetooth primarily operate on?
Bluetooth operates primarily in the 2.4 GHz ISM (Industrial, Scientific, and Medical) band.
Q11. What type of network does ZigBee create?
ZigBee creates low-power, low-data-rate mesh networks ideal for IoT applications like home automation, sensor networks, and industrial monitoring.
Q12. What is the typical range of Bluetooth?
Standard Bluetooth (Class 2) has a typical range of about 10 meters (33 feet), though Class 1 devices can reach up to 100 meters.
Q13. What is the purpose of RTS/CTS mechanism in IEEE 802.11?
RTS (Request to Send) and CTS (Clear to Send) frames are used to reserve the wireless channel, helping to solve the hidden station problem by informing all stations about the upcoming transmission.
Q14. What technology does 4G LTE use for its air interface?
4G LTE uses OFDMA (Orthogonal Frequency Division Multiple Access) for the downlink, which efficiently divides bandwidth into many subcarriers for multiple users.
Q15. What is MIMO in wireless networking?
MIMO (Multiple Input Multiple Output) uses multiple antennas at both transmitter and receiver to improve throughput and reliability through spatial multiplexing and diversity.
Q16. What is MU-MIMO and how does it differ from SU-MIMO?
MU-MIMO (Multi-User MIMO) transmits to multiple users simultaneously using spatial multiplexing, while SU-MIMO (Single-User MIMO) dedicates all spatial streams to one user at a time.
Q17. What is frequency reuse in cellular networks?
Frequency reuse assigns the same set of frequencies to non-adjacent cells that are far enough apart to minimize interference, maximizing the use of limited spectrum.
Q18. What is the maximum theoretical speed of IEEE 802.11ac (Wi-Fi 5)?
IEEE 802.11ac (Wi-Fi 5) can theoretically achieve up to 6.9 Gbps using 8 spatial streams with 160 MHz channels and 256-QAM modulation.
Q19. What is OFDMA and how does it improve Wi-Fi 6?
OFDMA divides the channel into resource units that can be assigned to different users simultaneously, improving efficiency for multiple concurrent users, especially with small packets.
Q20. What is the difference between infrastructure mode and ad-hoc mode in Wi-Fi?
In infrastructure mode, devices communicate through a central access point. In ad-hoc mode, devices communicate directly with each other without an access point.
Q21. What does WPA3 improve over WPA2?
WPA3 uses SAE (Simultaneous Authentication of Equals) replacing PSK, providing forward secrecy and protection against offline dictionary attacks even with weak passwords.
Q22. What is handoff (handover) in cellular networks?
Handoff is the process of transferring an active call or data session from one cell to another without interruption as the mobile user moves between coverage areas.
Q23. What is beamforming in 5G and Wi-Fi 6?
Beamforming uses multiple antennas to focus radio signals toward specific devices rather than broadcasting in all directions, improving signal strength, range, and reducing interference.
Q24. What is the key technology difference between 5G mmWave and sub-6 GHz 5G?
5G mmWave uses frequencies from 24-100 GHz offering multi-Gbps speeds but with very limited range and poor penetration. Sub-6 GHz provides wider coverage with lower but still significant speeds.
Q25. What is network slicing in 5G?
Network slicing creates multiple virtual networks on shared physical infrastructure, each tailored for specific requirements like low latency (autonomous vehicles), high bandwidth (video), or massive IoT connectivity.
Q26. What is the role of the Mobility Management Entity (MME) in LTE architecture?
The MME handles control-plane functions in LTE including user authentication, security, idle-mode tracking, paging, bearer establishment, and handover management.
Q27. In Wi-Fi 6 (802.11ax), what is BSS Coloring?
BSS Coloring assigns a color (identifier) to each BSS. Stations can identify if a detected signal is from their own BSS or a neighboring one, allowing them to ignore inter-BSS signals and transmit concurrently.
Q28. What is the KRACK (Key Reinstallation Attack) vulnerability?
KRACK exploits the WPA2 four-way handshake by manipulating cryptographic handshake messages, forcing nonce reuse and allowing attackers to decrypt, replay, and forge packets.
Q29. What is the exposed station problem in wireless networks?
The exposed station problem occurs when a station unnecessarily delays its transmission because it detects another station's signal, even though its own transmission would not interfere at the other station's receiver.
Q30. What is the purpose of Target Wake Time (TWT) in Wi-Fi 6?
TWT allows the access point to negotiate specific wake times with each device, enabling IoT and mobile devices to sleep longer and wake only when needed, significantly reducing power consumption.
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