Orthogonal Frequency Division Multiple Access (OFDMA)

Wireless & Mobile Communications

This set of Wireless & Mobile Communications online quiz focuses on “Orthogonal Frequency Division Multiple Access (OFDMA)”.

1. OFDMA stands for ________
a) omnidirectional frequency division multiple access
b) orthogonal frequency duplex multiple access
c) orthogonal frequency divider multiple access
d) orthogonal frequency division multiple access

2. Why is a cyclic prefix required in an OFDMA?
a) To ensure symbol time is an integer number
b) To help overcome multipath and ISI
c) To maintain orthogonality
d) To make OFDMA scalable

3. What does the DC subcarrier indicate?
a) Identity of the cell
b) Antenna configuration
c) Center of OFDM channel
d) Format of data channel

4. What processing step combines multiple OFDM subcarriers into a single signal for transmission?
a) FFT
c) RF combining
d) Channel mapping

5. Which property of OFDMA system allows adjacent subcarriers to be used without interference?
a) Orthogonality
b) Orthodoxy
c) Octagonality
d) Originality

6. In OFDMA, what is the relationship between the subcarrier spacing f and symbol time t?
a) f=t
b) f=1/2t
c) f=1/t
d) no relation

7. OFDM is a technique for 3G mobile communication.
a) True
b) False

8. OFDM uses complex equalizers.
a) True
b) False

9. When we divide band of Orthogonal Frequency Division Multiplexing (OFDM) into sub bands, it diminishes effects of __________
a) noise
b) collision
c) interference
d) signals absence

10. Common data rates of IEEE 802.11 OFDM are ____________
a) 18 Mbps
b) 200 Mbps
c) 50 Mbps
d) 54 Mbps


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