CTA Wireless Communications & Mobile Technologies 1 — Questions and Answers
Question 1: Which generation of mobile technology first introduced packet-switched data services alongside circuit-switched voice in the US?
- 1G
- 2G (GPRS/EDGE) (Correct answer)
- 3G (UMTS/HSPA)
- 4G LTE
Correct answer: 2G (GPRS/EDGE)
2G networks introduced GPRS and EDGE, enabling packet-switched data while still supporting circuit-switched voice calls.
Question 2: What does the term 'handoff' (or handover) refer to in cellular networks?
- Transferring an active call from one base station to another (Correct answer)
- Converting analog signals to digital
- Assigning a frequency channel to a new subscriber
- Switching from voice to data mode
Correct answer: Transferring an active call from one base station to another
Handoff is the process of transferring an ongoing call or data session from one cell tower (base station) to another as the user moves.
Question 3: In the US, which spectrum band is commonly referred to as 'low-band' 5G and offers the widest coverage?
- millimeter wave (mmWave) above 24 GHz
- Mid-band around 3.5 GHz
- Sub-1 GHz bands (600–900 MHz) (Correct answer)
- C-band at 3.7–3.98 GHz
Correct answer: Sub-1 GHz bands (600–900 MHz)
Sub-1 GHz spectrum (such as 600 MHz and 700 MHz) propagates farther with better building penetration, making it ideal for wide-area 5G coverage.
Question 4: What is the primary purpose of MIMO (Multiple-Input Multiple-Output) technology in wireless systems?
- To reduce transmit power
- To increase spectral efficiency and throughput using multiple antennas (Correct answer)
- To eliminate the need for modulation
- To convert Wi-Fi signals to cellular
Correct answer: To increase spectral efficiency and throughput using multiple antennas
MIMO uses multiple antennas at both transmitter and receiver to send and receive more data simultaneously, improving spectral efficiency.
Question 5: Which wireless standard defines Wi-Fi 6 (802.11ax)?
- IEEE 802.11n
- IEEE 802.11ac
- IEEE 802.11ax (Correct answer)
- IEEE 802.11ad
Correct answer: IEEE 802.11ax
Wi-Fi 6 is formally defined by the IEEE 802.11ax standard, introducing OFDMA and BSS coloring for improved efficiency in dense environments.
Question 6: What is the difference between FDD and TDD in mobile networks?
- FDD uses separate frequency bands for uplink and downlink; TDD uses the same frequency but alternates time slots (Correct answer)
- FDD uses time slots; TDD uses separate frequencies
- FDD is only for 4G; TDD is only for 5G
- FDD requires more antennas than TDD
Correct answer: FDD uses separate frequency bands for uplink and downlink; TDD uses the same frequency but alternates time slots
Frequency Division Duplex (FDD) separates uplink and downlink on different frequencies, while Time Division Duplex (TDD) alternates between uplink and downlink on the same frequency.
CTA Wireless Communications & Mobile Technologies 1
Which generation of mobile technology first introduced packet-switched data services alongside circuit-switched voice in the US?