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WiFi Channel Planning Best Practices

When planning the deployment of a wireless network consisting of multiple access points, it’s important to create a channel plan that minimizes co-channel interference, which happens when two different access points use the same WiFi channel.
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802.11 Wireless Networking 101
Choosing the Best WiFi Channel Available
Avoiding Co-Channel Interference
Conclusion

802.11 Wireless Networking 101

To properly tackle the subject of WiFi channel planning, we must first explain the basic concepts of 802.11 wireless networking. The 802.11 specifications list the radio frequency spectrum allocated to WiFi, including but not limited to 2.4 GHz and 5 GHz frequency bands, which dominate the consumer market.

WiFi channels waves

2.4 GHz

The 802.11b, 802.11g, and 802.11n specifications utilize the 2.4 GHz frequency band, which is divided into 14 channels (only 11 of these channels are commonly utilized in North America), with each channel occupying at least 20 MHz.

Channel Frequency(MHz) North America Japan Most of world
1 2412 Yes Yes Yes
2 2417 Yes Yes Yes
3 2422 Yes Yes Yes
4 2427 Yes Yes Yes
5 2432 Yes Yes Yes
6 2437 Yes Yes Yes
7 2442 Yes Yes Yes
8 2447 Yes Yes Yes
9 2452 Yes Yes Yes
10 2457 Yes Yes Yes
11 2462 Yes Yes Yes
12 2467 No Yes Yes
13 2472 No Yes Yes
14 2484 No 11b only No

The problem is that WiFi channels in the 2.4 GHz band are spaced only 5 MHz apart (despite being 20 MHz wide). This means that only channels 1, 6, 11, and 14 don’t overlap with each other.

2.4 GHz

Since channel 14 is not available in North America, we’re left with only three non-overlapping WiFi channels in the 2.4 GHz band when planning the deployment of a wireless network.

5 GHz

The 802.11a, 802.11n, and 802.11ac specifications utilize the more heavily regulated 5 GHz band, which offers up to 165 non-overlapping channels, with a WiFi channel width of 20 MHz.

The situation in the 5 GHz band is somewhat complicated by the fact that the latest 802.11 specifications make it possible for multiple channels to be grouped together to create as much as 160 MHz wide channels.

The main advantage of these wide channels is that they can carry more data

The main advantage of these wide channels is that they can carry more data, but this ability comes at a price, and that price is a higher noise floor. For 20 MHz channels in the 5 GHz band, this floor is approximately -101 dBm. For 160 MHz channels, it’s -92 dBm.

One way to counter the increase in the level of background energy is to minimize the distance between access points and client devices. With ultra-wide channels, this is often not possible without amplifying self-interference, making smaller channel sizes the preferred option for many WiFi deployments.

2.4 GHz vs 5 GHz

Due to their different physical properties, there are several important differences between 2.4 GHz and 5 GHz WiFi signals.

2.4 GHz vs 5 GHz

The 2.4 GHz wavelength offers superior range thanks to its ability to penetrate solid objects, such as walls and furniture, reasonably well. Higher frequency signals lose considerably more power when they encounter a solid obstacle, making them suitable primarily for short-distance applications.

The 5 GHz wavelength offers a much higher bandwidth (up to 1 Gbps), making it great for high-bandwidth applications like 4K video streaming.

most modern WiFi routers can broadcast simultaneously a 2.4 GHz and 5 GHz signal from the same unit

While both wavelengths are susceptible to signal interference, 2.4 GHz wireless networks are affected by a whole range of radio frequency-emitting devices, including cordless phones, microwave ovens, wireless security cameras, gaming controllers, garage door openers, baby monitors, and others.

The good news is that most modern WiFi routers can broadcast simultaneously a 2.4 GHz and 5 GHz signal from the same unit, giving you the best of both worlds. Because dual-band routers make it possible to assign a single SSID to the two bands, users only see one network, and can connect to it with ease.

Choosing the Best WiFi Channel Available

To select the best channel for 5 GHz and 2.4 GHz WiFi, you need a WiFi channel scanner like NetSpot. With NetSpot, you can quickly and painlessly gather information about surrounding WiFi networks and see WiFi channel utilization at a glance.

To discover the best channel for WiFi with NetSpot:

  1. Download and launch NetSpot.
  2. Use the Discover Mode to collect every detail about surrounding WiFi networks.
Discover Mode
  1. Select all WiFi networks that you want to visualize.
  2. Click the Details button in the bottom-left corner.
  3. Click Channels 2.4 GHz or Channels 5 GHz to see the distribution of WiFi channels in the two bands.

Pick the least utilized non-overlapping channel available. That’s how easy it is to select the best channel for WiFi if you have only one access point. But what about wireless networks consisting of multiple access points?

Avoiding Co-Channel Interference

When planning the deployment of a wireless network consisting of multiple access points, it’s important to take into consideration co-channel interference.

WiFi interference

One of the most common mistakes made by businesses and organisations when deploying a wireless network is to configure all access points to use the same WiFi channel. Such business and organisations typically experience major issues with throughput because all data is flowing through a single channel with limited capacity.

Your goal should be to provide seamless roaming by overlapping RF cell coverage while simultaneously avoiding overlapping frequency space, which could result in slower network speeds.

NetSpot’s Survey Mode an easy-to-use WiFi heatmapping

To achieve this goal, it’s necessary to determine the coverage of each access point and position them in such a way that the entire area is covered with enough overlap for seamless roaming. This can be done using NetSpot’s Survey Mode, an easy-to-use WiFi heatmapping feature capable of creating interactive heatmaps with detailed information on all surveyed wireless networks in every point of the map.

WiFi Heatmap

To create a WiFi site survey with NetSpot:

  1. Download and launch NetSpot.
  2. Switch to the Survey mode using the prominent button in the toolbar.
  3. Name your WiFi site survey project and import a map of the area you want to survey.
  4. Move from one place to another until you cover the whole area.
  5. Click the Stop Scan button located in the bottom-left corner when you’re done.

Equipped with the information provided by NetSpot, configure your access points so that no two access points with overlapping coverage use the same WiFi channel. As we’ve already explained, you should keep the 2.4 GHz channels to 1, 6, and 11 since these are the only three non-overlapping channels available, at least in North America.

Non-Overlapping Channels

In the 5 GHz band, there are far more channels to choose from, and most modern access points can set the most appropriate channel automatically, making it far easier to avoid co-channel interference and achieve flawless coverage and excellent capacity.

Conclusion

When planning the deployment on any wireless network, it’s important to take into consideration the fact that WiFi channels overlap with other adjacent channels. A WiFi channel scanner and heatmapping tool like NetSpot makes it easy to discover all kinds of WiFi issues associated with co-channel interference and poor coverage.

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