2.4, 5 and 6 GHz: choosing WiFi bands

WiFi runs in three frequency bands: 2.4, 5 and 6 GHz. Lower frequencies travel further and through walls more easily, while higher frequencies offer far more channels and cleaner airspace. Most enterprise networks today rely on 5 GHz as the workhorse, add 6 GHz for newer devices, and keep 2.4 GHz for older or simpler equipment.

The three bands at a glance

2.4 GHz

The 2.4 GHz band has the longest range and the widest device support. Nearly every WiFi device ever made can use it, including many sensors, building controls, printers and older industrial equipment.

Its weaknesses are serious, though. There are only three non-overlapping 20 MHz channels in North America (1, 6 and 11), so access points in a dense building inevitably overlap. The band is also shared with microwave ovens, Bluetooth and many other devices, and because signals travel so far, neighbouring networks are heard from a long way off. The result is a crowded, noisy band with limited capacity.

In enterprise design, 2.4 GHz is usually kept for devices that need it, often with some access points' 2.4 GHz radios turned off or set to low power to limit overlap.

5 GHz

The 5 GHz band is the backbone of most enterprise WiFi. It offers many more channels than 2.4 GHz, so access points can be placed closer together without competing, and it carries far less non-WiFi interference.

Some 5 GHz channels require dynamic frequency selection (DFS), meaning access points must listen for radar and leave a channel if they detect it. DFS channels add useful capacity, but near airports or weather radar they can cause sudden channel changes, and some client devices do not support them. Signals at 5 GHz lose more strength through walls than 2.4 GHz, which is one reason enterprise networks use more access points placed closer to users.

6 GHz

Canada has opened the 6 GHz band for licence-exempt WiFi use. It adds a large amount of new spectrum, enough for many wide channels, and it is available only to newer WiFi 6E and WiFi 7 devices, so there is no crowd of legacy devices slowing it down. Security is stronger too: 6 GHz networks require WPA3.

The trade-offs are range and device support. 6 GHz signals do not reach as far or pass through walls as easily as 5 GHz, so coverage from the same access point is smaller. Only newer phones, laptops and tablets can use it, and many specialized devices such as scanners, medical equipment and building sensors will not support it for some time. Power limits and the rules for indoor and outdoor use are set by Innovation, Science and Economic Development Canada (ISED); check current rules and equipment certification during design.

How to choose

Most buildings do not choose one band; they decide what each band is for.

• Start from the devices. List the devices that must work, especially specialized ones, and which bands they support. A warehouse full of older scanners needs a solid 2.4 or 5 GHz design regardless of what new laptops can do.
• Design coverage for the most important band. In most new designs that is 5 GHz, with 6 GHz coverage checked separately since its cells are smaller.
• Limit 2.4 GHz overlap. Do not run every 2.4 GHz radio at full power just because it is available.
• Use band steering carefully. Encouraging capable devices onto 5 or 6 GHz frees 2.4 GHz for the devices that need it, but aggressive steering can cause connection problems for some clients.
• Plan for 6 GHz now. Even if few devices use it today, access points installed now will be in service for years. See WiFi 6, 6E and 7 explained.

How ehZee can help

We design networks around the devices you actually rely on, deciding what each band is for and how channels and power are planned across all three. Our WiFi design and build service includes band and channel planning and a validation survey for each band. For the channel side, read WiFi channel planning.

Common questions