Chapter 8 - HT, VHT, and HE Operations Flashcards
When using an 8x8:8 VHT AP and MU-MIMO how many MU-MIMO client stations can be in a single group?
a. 2
b. 4
c. 6
d. 8
4
When using transmit beamforming in VHT, which technique is used for the AP and STA to determine how the beams are to be formed?
a. NDP sounding
b. Beamformee enumeration
c. Beamformer enumeration
d. VHT beamform arbitration
NDP Sounding
only method used in VHT
Upon how many channels can an AP and an associated STA simultaneously use MIMO without changing channels?
a. One
b. Two
c. Four
D. Eight
One
Within the context of MIMO transmissions, what term is used to describe the known channel properties?
a. CCI
b. CCA
c. CSI
d. CIA
CSI (Channel State Information)
What is the maximum number of client stations that can simultaneously transmit block acknowledgments when using MU-MIMO?
a. One
b. Two
c. Four
d. Eight
One
Each station must acknowledge frames which is why answer is 1
Which frame type can contain multiple MSDU payloads from multiple source addresses?
a. A-MPDU
b. A-MSDU
c. Block Acknowledgment
d. NDP Sounding
A-MSDU
must all be for the same DA
What kind of beamforming is used in VHT?
a. MU-MIMO
b. A-MPDU
c. Implicit
d. Explicit
Explicit (mandatory in 802.11ac)
Implicit is used in 802.11n
Where should you look fo rthe maximum MPDU length supported by a VHT AP in a beacon frame?
a. in the VHT capabilities
b. in the MIMO capabilities
c. in the NDP Sounding element
C in the channel width support
in the VHT capabilities
True or False: The MIMO channel coefficients are sent to the beamformee by the beamformer.
False - sent from the beamformee to the beamformer
Why is beamforming difficult in most deployments?
a. the CSI varies due to non-802.11 noise sources
b. the CSI varies because client stations are mobile
c. the APs and STAs support different versions of MIMO
d. The use of 20 MHz wide channels does not provide enough bandwidth
the CSI varies because client stations are mobile
