D3-WLAN Systems

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Keywords: WLAN, Wifi, IEEE 802.11,

⌘ WLAN standard IEEE_802.11

The newest member in the 802.11 family are the 802.11ac and the 802.11u standards

IEEE 802.11ac

802.11ac is introduced to operate in the 5 GHz band, and has, according to the Cisco White Paper, the following features:

  • More channel bonding, increased from the maximum of 40 MHz in 802.11n, and now up to 80 or even 160 MHz (for 117% or 333% speed-ups, respectively)
  • Denser modulation, now using 256 quadrature amplitude modulation (QAM), up from 802.11n's 64QAM (for a 33% speed burst at shorter, yet still usable, ranges)
  • More multiple input, multiple output (MIMO). Whereas 802.11n stopped at four spatial streams, 802.11ac goes all the way to eight (for another 100% speed-up).

Second-generation products should also come with a new technology, multiuser MIMO (MU-MIMO). Whereas 802.11n is like an Ethernet hub that can only transfer a single frame at a time to all its ports, MU-MIMO allows an AP to send multiple frames to multiple clients at the same time over the same frequency spectrum.

IEEE 802.11u

802.11u is a new interworking standard, and allows users to connects to access points, based on their relations to other Wifi providers. As an example: A user of "UiO" may connect to "UNIK" based on the 802.11u agreement between UiO and UNIK.


[Source:Cisco White Paper "801.11ac: The Fifth Generation of WiFi]

Keyword D3-WLAN Systems

D3-WLAN Systems
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Related information

⌘ Earlier Presentations on WLAN systems

Susana Rodriguez de Novoa:

⌘"WLAN communication" 802.11


[Presentation G. Fettweis, IEEE VTC forum Baltimore], http://www.ieeevtc.org/plenaries/vtc2007fall/28.pdf

⌘ 802.11 ad standard

  • addresses 60 GHz communications, 5.7 GHz available bandwidth
  • Wavelength mm
  • antenna on chip
Application areas:
  • set-top boxes, TV, high-bandwidth cable replacement
  • direct backbone links
  • industrial construction area
  • communications in public places
Conclusions from NY University, [1]
  • Measurements at 38 and 60 GHz show that NLOS links can be made with steerable antennas, with 20 – 30 dB loss compared to free space line-of-sight.
  • A link was always made using steerable antennas within a 200 m cell radius.
  • 38 GHz showed more NLOS links than 60 GHz
  • Cellular AOA distributions show BS should be deployed site-specifically (due to shadowing of buildings)
  • Worst RMS delay spread link was 122ns, similar for peer- to-peer and cellular
Further reading