wlan.md 1.6 KB


title: WLAN Theory breadcrumbs:

  • title: IT
  • title: Network --- {% include header.md %}

Specifications

Wi-Fi

|Standard|Name|Frequency (GHz)|Bandwidth|Modulation| |-|-|-|-|-| |802.11b||2.4|22|DSSS| |802.11a||5|5/10/20|OFDM| |802.11g||2.4|5/10/20|OFDM| |802.11n|Wi-Fi 4|2.4 + 5|20/40|MIMO-OFDM| |802.11ac|Wi-Fi 5|5|20/40/80/160|MIMO-OFDM| |802.11ax|Wi-Fi 6|1-6 (ISM)|20/40/80/80+80|MIMO-OFDM|

Not Wi-Fi

|Standard|Name|Bands (GHz)|Bandwidth (MHz)|Modulation| |-|-|-|-|-| |802.11||2.4|22|DSSS/FHSS| |802.11ad|WiGig (gen 1)|60|2,160|OFDM|

Planning & Implementation

  • Always perform a survey before to identify internal and external existing WLANs and RF interference.
  • Windows may block relevant frequencies.
  • Don't set stations' transmit power too high.
    • Other associated stations' max transmit power may be much lower, causing asymmetric connections. They may still roam to them from a more appropriate BSS, though, since the problem is not apparent until after associated.
    • It increases interference with other stations may contribute to the hidden and exposed node problems.
    • It may overheat the device.
    • It may violate regulations.
  • Disable legcy protocols (such as 802.11 a, b and g). Legacy devices take up too much time when accessing the medium.
  • Move as many devices as possible to the 5GHz band. Try to reserve the 2.4GHz band for legacy/simple and distant devices.
  • The 2.4GHz (ISM) band is more susceptible to interference since the frequency is used by e.g. Bluetooth and microwave ovens.
  • Changes in the physical environment may cause changes in the WLAN coverage.

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