Chapter 3 - The Physical Layer

Question 1

What is the purpose for the Carrier Sense/Clear Channel assessment?
a. to determine the state of the medium
b. to determine which PHY is in use within the service sets
c. to determine the contention method in use
d. to determine the association count of the AP

Answer 1

to determine the state of the medium

Question 2

The PHY protocol data unit (PPDU) is comprised of how many parts?
a. 2
b. 4
c. 3
d. 5

Answer 2

3 (Preamble, Header, PSDU)

Question 3

Which layer is responsible for transmitting and receiving bits onto and off the medium?
a. the SAP
b. The LLC
c. The PHY
d. the MAC

Answer 3

the PHY

Question 4

What part of a frame transmission contains the Sync field and start frame delimiter (SFD) field?
a. the MPDU
b. the Preamble
c. the MSDU
d. the Payload

Answer 4

the Preamble

Question 5

The higher data rates found in OFDM are largely due to the use of which modulation type?
a. DBPSK
b. QAM
c. DQPSK
d. CCK

Answer 5

QAM

Question 6

Of the 52-subcarriers used on a single OFDM channel, how many are available for transmitting data versus being used as pilot subcarriers?
a. 4
b. 48
c. 51
d. 36

Answer 6

48

Question 7

Within which portion of an HT-OFDM header can you determine if the Greenfield mode of operation is in use?
a. The A-MPDU paramters
b. the HT Capabilities information
c. the support MCS set
d. the Element ID

Answer 7

HT Capabilities (set to 0)

Question 8

When using VHT-OFDM in a mixed environment, what do the PPDUs have in common with legacy HT PPDUs?
a. the first field is the same
b. the first three fields are the same
c. the MU-VHT SIG-A Format is the same
d. the SU-MIMO VHT-SIG-B format is the same

Answer 8

the first three fields are the same

Question 9

True or false: An MSDU and PSDU are essentially the same thing

Answer 9

True