Every Wi-Fi standard promises faster speeds and better performance. However, every standard also experiences the real-world limitations of enterprise networking.
Things tend to change fast in Wi-Fi. A new standard that promises even more fantastic performance gains is always just around the corner. At the same time, the laws of physics and the power regulations that limit Wi-Fi 6's range capabilities are inescapable.
Long-distance coverage is less relevant where Wi-Fi is dense -- for example, in offices with carpeted spaces where numerous smaller cells serve many clients. This article evaluates how current WLAN standards affect Wi-Fi range.
Wi-Fi range basics
The effective range of any transmitted signal is determined by several key aspects that shape the output power or to receive signals. Examples of factors that affect range include the following:
Signal frequency.
Output power.
The ability of the antenna, which depends on proper build and specifications such as aperture.
Frequencies
Today's 802.11-based WLANs operate in the 2.4 GHz and 5 GHz bands for Wi-Fi 6, and the 2.4 GHz, 5 GHz and 6 GHz bands for Wi-Fi 6E and 7. The higher the frequency range, the less effective the range and the signal's ability to penetrate objects at the same output power.
Power
The FCC regulates all Wi-Fi bands and channels within the bands in the U.S. In the 2.4 GHz band, Wi-Fi power before the antenna can be up to 1 watt, but is typically 100 milliwatts (mW) or less. Of the antenna, the FCC allows up to 4 watts effective isotropic radiated power. It's more nuanced in 5 GHz and 6 GHz, which both depend on the specific sub-band of frequencies in use and whether the environment is indoor or outdoor. But, as with 2.4 GHz, client output power is usually less than 100 mW.
Antenna patterns
Antennas tend to be omnidirectional or built with some amount of directionality. Directional antennas can shape the available signal, sending it farther in a given direction. Think about how a round water balloon changes shape when you squeeze it. A highly directional antenna will yield a greater range in a given direction at the expense of reducing it in all other directions.
Wi-Fi range comparison
As frequency increases, the effectiverange at a given power level decreases when typical antennas are in use. This premise extends beyond Wi-Fi and is true for all radio technologies.
The channel width also affects the effective range. Wider channels distribute available power across the entire channel width and require a higher signal-to-noise ratio (SNR). Each new standard brings even wider channels with it. Today's specifications support channel widths that are impractical in the real world.
Wi-Fi data rate vs. range
Wi-Fi generates the highest data rates when client devices are close to the access point (AP) and have signals that are strong and clean, regardless of standard. As clients roam away from the AP, signal strength and SNR lessen, and data rates drop off in well-defined steps.
Consider the now obsolete 802.11b standard. Its best rate was 11 megabits per second, but as the client device moved farther away from the AP, the rate dropped to 5.5 Mbps, then 2 Mbps and eventually to 1 Mbps. The same step-down effect occurs with Wi-Fi 6 range -- as well with 6E and 7 -- but because these standards are more complicated, dozens, if not hundreds, of permutations now exist.
Even as Wi-Fi 7 begins to gain attention, the industry is asking the same questions about range that have been raised throughout the history of 802.11-based wireless networking.
Lee Badman
In enterprise WLAN environments, cells permit high-bandwidth roaming. As a result, clients are always close to an AP, and the lower end of the rate versus range principle doesn't apply. The only practical option to extend the signal in business WLAN spaces is to use highly directional antennas to cover an area. Unlike residential deployments, range extenders and repeaters don't integrate well in enterprise Wi-Fi.
Even as Wi-Fi 7 begins to gain attention, the industry continues to ask the same questions about range that have been raised throughout the history of 802.11-based wireless networking. Similar to earlier standards, Wi-Fi 7 is bound by it regulatory limits for power output in all three bands. Antenna selection still matters in shaping Wi-Fi 7 cells to gain longer coverage in a certain direction.
By taking advantage of 6 GHz's newest modulation magic and wider channels, Wi-Fi 7 -- like Wi-Fi 6 and 6E -- will generate the highest data rates when devices are close to the AP. That might give the newest standard a fighting chance to live up to its promise.
Lee Badman is a network architect specializing in wireless and cloud technologies for a large private university. He's also an author and frequent presenter at industry events.
