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OFDMA System Analysis and Design
RF Cafe Quiz #30

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All RF Cafe quizzes would make perfect fodder for employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job.

Some of these books used in quizzes are available as prizes in the monthly RF Cafe Giveaway.

Note: Many answers contain passages quoted in whole or in part from the text.


RF Cafe - OFDMA System Analysis and Design This quiz is based on the information presented in OFDMA System Analysis and Design, by Samuel C. Young. Published by Artech House.
 Note: Some of these books are available as prizes in the monthly RF Cafe Giveaway.



1.  Which of these are advantages of Frequency Division Multiplexing (FDM)?

a)  Effective at combating intersymbol interference (ISI) and multipath fading
b)  Can adjust modulation and coding for each subcarrier
c)  Simple equalization
d)  All the above



2.  Which transmission scheme has the highest spectral efficiency?

a)  Frequency Division Multiplexing (FDM)
b)  Orthogonal Frequency Division Multiplexing (OFDM)
c)  Orthogonal Frequency Division Multiple Access (OFDMA)
d)  Uber Orthogonal Frequency Division Multiple Access (UOFDMA)



3.  In multi-path signal computations, what is the "plane-earth" model?

a)  A model used for airborne system calculations
b)  A model that considers the earth surface to be flat
c) c)  A model that neglects obstacles, i.e., "plane"
d)  All the above



4.  What are "linear block codes" in channel coding lingo?

a)  A class of codes used for error detection or correction
b)  Linear coding techniques that divide cells into city blocks
c)  Coding schemes using a building block construction analogy
d)  None of the above



5.  How does a high peak-to-average power ratio (PAPR) affect OFDM systems?

a)  Not at all
b)  Minimally
c)  Significantly
d)  OFDM cannot be used with a high PAPR



6.  What is the "physical layer" of a protocol?

a)  It is the code (software/firmware) responsible for the actual transmission
     of bits across the medium
b)  The actual cable or wireless link interconnecting the transmitter and receiver
c)  Another name for the hardware
d)  Another name for the MAC (Medium Access Control)



7.  What is "receive diversity?"

a)  Having a receiver capable of operating in a "bit-blind" manner
b)  Using all arriving bits regardless of signal quality
c)  Giving preference to "0s" over "1s" out of fairness
d)  Dynamically selecting the best signal from multiple antennas



8.  Which of the following are real names given to scheduling algorithms?

a)  Round robin
b)  Temporary removal scheduler
c)  Proportional fairness
d)  All the above



9.  During a cell scanning interval, which neighboring station "association level" refers to
     Network-Assisted Association Reporting?

a)  Association Level 0
b)  Association Level 1
c)  Association Level 2
d)  Association Level 3



10.  What is a cryptographic "hash?"

a)  Masking noise
b)  A function that returns a fixed-size bit string from a variably-sized input string
c)  An algorithm that chops up messages to disguise them
d)  Playful bantering between coders





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