WIFI 5GHZ CHANNELS

The IEEE recognize that while 5 Ghz has advantages over 2.4 Ghz its also an increasingly crowded band which is why the working committee moved to the 60 Ghz band to find some wider channels to provide gigabit data rates. At 60 Ghz the signals are confined largely to line of sight so the frequencies are best off in large open areas. Global efforts to open up 6 GHz may take several years before it can be repurposed around the world.

CHANNELBASE FREQUENCYFREQUENCY RANGECHANNEL WIDTH
3651805150-550020
3851905170–521040
4052005190–521020
4252105170–525080
4452205210–523020
4652305210–525040
4852405230–525020
5052505170–5330160
5252605250–527020
5452705250–529040
5652805270–529020
5852905250–533080
6053005290–531020
6253105290–533040
6453205310–533020
6853405330–535020
9654805470–549020
10055005490–551020
10255105490–553040
10455205510–553020
10655305490–557080
10855405530–555020
11055505530–557040
11255605550–557020
11455705490–5650160
11655805570–559020
11855905570–561040
12056005590–561020
12256105570–565080
12456205610–563020
12656305610–565040
12856405630–565020
13256605650–567020
13456705650–569040
13656805670–569020
13856905650–573080
14057005690–571020
14257105690–573040
14457205710–573020
14957455735–575520
15157555735–577540
15357655755–577520
15557755735–581580
15757855775–579520
15957955775–581540
16158055795–581520
16558255815–583520

The Wi-Fi 5 Ghz channels are largely allocated into a few narrowband 10 MHz channels that were allocated for 802.11a use, larger numbers of 20 Mhz channels and a smaller number of 40 Mhz channels. Wideband channels were also established for future standards with higher speed requirements.

Originally,  802.11a was the first standard to use the 5 Ghz band. The 802.11b and 802.11g use the crowded 2.4 GHz ISM band. 2.4 Ghz is also shared by microwave ovens, cordless telephones and a wide range of other consumer devices such as bluetooth.

The table shows each of the available channels, the base frequency and the frequency span. The channel width is given so that a network network equipment can select the appropriate channels to prevent poor performance.

Modern access point hardware now provides automatic channel selection to minimize interference. Depending on the channel size selected, tables can be used to select the appropriate channel as 5 Ghz has a wide diversity of channel sizes that are not well ordered.

Many busy areas such as food courts in larger shopping centers, airports lounges and similar areas may have several access point boxes installed. By using 5 Ghz even large pools of users can be easily handled.

Some densely populated urban areas have so many access points that its is hard for them all to not interfere with one another even with automatic channel selection.

The main disadvantage of 5GHz is that it does not penetrate walls near as well as 2.4Ghz does. Modern Wi-Fi adapter are well equipped to handle very weak signals to compensate. 5GHz is at its best in open areas with larger numbers of users and access points.

This table is designed with actual channels available on a global basis. A few channels are regional which are not included as space limitations prevent that much sophistication.

At present almost the entire 5-6 Ghz band has been allocated for wireless LAN applications. Some channels may not be available in some areas due to local requirements.

In 2007 the FCC mandated that devices in the 5GHz band use dynamic frequency selection. The FCC also mandated transmit power control. The goal was to minimize potential interference with weather radar and military applications. Around the world standards are now nominally becoming standardize enough to make 5GHz a global WLAN standard that works.

The upcoming 802.11ac is expected to be a refinement of 802.11n. The IEEE has managed to take advantage of more sophisticated technology to continue to refine the use of 2.4 Ghz and 5Ghz networking. 802.11ac will use different channels when set to 40MHz channel width or 80MHz as shown on the chart. 802.11ax supports 160MHz channels and it will operate in only one of 2 available channels.

While wideband channels are shown on the chart, be aware that there is significant overlap between channels which were originally designed for 20 MHz systems. Work is being done to find additional bands that can be used for wideband.

Upcoming hardware is known to be designed for supporting several channels at once. For example 802.11ax hardware can handle 4 channels at once with 2.4GHz and 8 channels in the 5 Ghz band all at once. Some high-end access points now have 8T8R MU-MIMO capability.

Looking down the road, the technology for wireless networking has seen tremendous growth which suggests wired connections are now largely obsolete. With dynamic channel selection and more efficient use of available channels becoming the dominant technology the future for Wi-Fi looks very good.

6 GHZ IS NEXT

The 802.11ax working group is working to get 6 Ghz opened up world wide for use. Some of the bandwidth can be use for WiFi and some will be used for mobile services.  The 6 Ghz band is likely be amended around 2020 once the regulatory situation is cleared up.

LIST OF WIRELESS STANDARDS

  • 802.11a
  • 802.11b
  • 802.11g
  • 802.11n
  • 802.11ac
  • 802.11ad
  • 802.11af
  • 802.11ah
  • 802.11ax
  • 802.11az