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Channel planning involves identifying what channels are open for transmissions without interference and where Wi-Fi will have the best performance.
Key takeaways:
- 5 essentials of channel planning:
- Understand the potential for overlap and interference.
- Use the three non-overlapping channels on the 2.4 GHz band.
- Leverage the benefits of 5 GHz and its greater number of non-overlapping channels.
- Consider the pros and cons of channel bonding in 5 GHz.
- Learn how the 6 GHz band vastly expands non-overlapping channels.
Planning a successful Wi-Fi strategy means strategizing for minimal congestion and interference. And an important component in any network plan to ensure optimal performance is channel planning.
Both 5 GHz and 2.4 GHz frequency bands are made up of smaller components, known as channels, which are used by the network to send and receive signals. Ensuring you're transmitting data on the right channel is crucial so that access points (APs) and clients never have trouble sending and receiving these signals. When there are channel issues, people will quickly start complaining about lousy Wi-Fi.
5 channel planning basics
Channel planning is the process of being strategic about which Wi-Fi channels are being used by client devices. They’re broken down by which band they’re in, and each of the frequencies has its pros and cons and unique considerations. Here are five basics to get started:
1. Understand the potential for overlap and interference
Channel planning allows network managers to avoid channel overlap or congestion. So why do those lead to performance issues? Because of co-channel interference and adjacent channel interference.
There are only a certain number of channels in each frequency band, and access points and clients must wait for a clear pathway to transmit. Co-channel interference (CCI) happens when more than one AP is using the same channel, and those APs are within range of each other. Both APs and all of their clients will contend for access to the same channel, limiting their performance.
Adjacent channel interference is likened to trying to have a conversation in a crowd—multiple devices on partially overlapping channels send signals regardless of what is happening on another channel. Channels that overlap can “talk over each other,” resulting in collisions and poor Wi-Fi performance. The normal contention mechanism doesn’t work with partially overlapping channels.
2. Use the three non-overlapping channels on 2.4 GHz
There are 11 channels available for use in the 2.4 GHz band in the United States. However, only three of them—1, 6, and 11—are non-overlapping. This means there are only three slices of the band that you know will not interfere with each other. To avoid overlap and interference issues, those non-overlapping channels are the way to go in that band.
3. Utilize 5 GHz and its greater number of non-overlapping channels
The 5 GHz band offers a lot more spectrum than 2.4 GHz, so Wi-Fi engineers favor 5 GHz because of the resulting greater capacity. It’s far easier to avoid CCI in 5 GHz. There are 25 channels within this band, and all of them are non-overlapping.
Each channel in this band has 20 MHz of space, as do the three 2.4 GHz band non-overlapping channels. But the difference is total capacity—the 5 GHz band has many more non-overlapping channels where you can spread out and achieve more consistent connections.
Careful RF design encourages devices to attach to the faster 5 GHz band more readily to avoid congestion and poor performance. Further, it’s possible to expand the 20 MHz of space each channel offers through this next item …
4. Consider the pros and cons of wide channels in 5 GHz
If Wi-Fi engineers want more single-user throughput on this band, they can use channel bonding to create a 40 MHz channel by combining two 20 MHz channels. The wider the channel, the more data can be transmitted through it to a single client.
Wi-Fi allows even wider channel widths, including 80 MHz and 160 MHz, but these are too wide given the available spectrum in 5 GHz. Using those channel widths in the enterprise results in poor performance from high CCI.
Even 40 MHz channel widths have drawbacks and considerations. Bonding two channels means there are half the non-overlapping channels available and more devices competing for access to transmit. This creates co-channel interference in a dense environment, leading to delays. In addition, each wider channel worsens the signal-to-noise ratio, slowing transmission times and potentially harming throughput overall for distant clients.
So, while channel bonding can help obtain faster speeds in certain environments, it can also lead to more interference and worse throughput, specifically in high-density capacity deployments. A channel bonding strategy is more effective in low-density coverage setups.
5. The 6 GHz band vastly expands non-overlapping channels
The recent opening of the 6 GHz band has changed things dramatically for Wi-Fi. There are 59 non-overlapping 20 MHz channels in this band, roughly double what was previously available. This means connections can spread out significantly.
To leverage 6 GHz, Wi-Fi engineers have to make sure that devices have radios that operate in 6 GHz. These radios are branded as including Wi-Fi 6E support. Nevertheless, as equipment catches up, the significant expansion in the spectrum offers massive potential for better Wi-Fi performance and fewer channel planning considerations.
Wireless network monitoring enables better channel planning—and a great deal more
Knowing and applying channel planning best practices are crucial. But effectively managing performance in complex WLAN environments relies on knowing exactly what’s causing issues, including and beyond issues like co-channel and adjacent channel interference.
7SIGNAL provides this visibility. With continuous wireless experience monitoring, you have access to over 600 KPIs that show how clients experience connections from moment to moment. Network managers can quickly identify the root causes of problems and implement fast solutions—often proactively and before end-users even notice them.
Learn more about 7SIGNAL’s Sapphire Eye® and Mobile Eye® platforms, and try this quick online assessment from IDC to see the possible value of wireless network monitoring for your organization.
7SIGNAL® is the leader in wireless experience monitoring, providing insight into wireless networks and control over Wi-Fi performance so businesses and organizations can thrive. Our cloud-based wireless network monitoring platform continually tests and measures Wi-Fi performance at the edges of the network, enabling fast solutions to digital experience issues and stronger connections for mission-critical users, devices, and applications. Learn more at www.7signal.com.