PLANET WNL-U554A - Manual (Page 61)

150Mbps 802.11n Wireless USB Adapte r
WNL‐U554A
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Appendix D: FAQ
1. What is WMM?
Wi‐Fi Multimedia (WMM), a group of features for wireless networks that improve the user
experience for audio, video and voice applications. WMM is based on a subset of the IEEE
802.11e WLAN QoS draft standard. WMM adds prioritized capabilities to Wi‐Fi networks
and optimizes their performance when multiple concurring applications, each with different
latency and throughput requirements, compete for network resources. By using WMM,
end‐user satisfaction is maintained in a wider variety of environments and traffic conditions.
WMM makes it possible for home network users and enterprise network managers to
decide which data streams are most important and assign them a higher traffic priority.
2.
What is WMM Power Save?
WMM Power Save is a set of features for Wi‐Fi networks that increase the efficiency and
flexibility of data transmission in order to conserve power. WMM Power Save has been
optimized for mobile devices running latency‐sensitive applications such as voice, audio, or
video, but can benefit any Wi‐Fi device. WMM Power Save uses mechanisms included in the
IEEE 802.11e standard and is an enhancement of IEEE 802.11 legacy power saves. With
WMM Power Save, the same amount of data can be transmitted in a shorter time while
allowing the Wi‐Fi device to remain longer in a low‐power “dozing” state.
3.
What is GI?
GI stands for Guard Interval. It’s a measure to protect wireless devices from cross‐
interference. If there are two wireless devices using the same or near channel, and they are
close enough, radio interference will occur and reduce the radio resource usability.
4.
What is STBC?
STBC stands for Space‐Time Block Coding, which is a technique used to transfer multiple
copies of data by multiple antenna, to improve data transfer performance. By using multiple
antennas, not only data transfer rate is improved, but also the wireless stability.