PLANET WNL-9501 - Manual (Page 43)

802.11n Wireless PCI Express Adapte r
WNL‐9501
43
Appendix: 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 the 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 antennas, to improve data transfer performance. By using multiple antennas,
not only data transfer rate is improved, but also the wireless stability.