What is WiFi 6 (802.11ax)?

WiFi 6 is the wireless networking standard based on the IEEE 802.11ax specification, and it represents a fundamental shift in how WiFi was designed. Previous generations focused primarily on increasing the maximum speed a single device could achieve. WiFi 6, certified by the Wi-Fi Alliance in September 2020, instead prioritised handling many devices efficiently on crowded networks. The result is a standard that performs better in real-world conditions than its raw speed numbers might suggest.

The average home in 2026 has 15 to 25 WiFi-connected devices. Smartphones, laptops, tablets, smart speakers, security cameras, thermostats, light bulbs, and appliances all compete for the same wireless bandwidth. WiFi 5 was not designed for this density. WiFi 6 was built specifically to handle it.

OFDMA: Serving Multiple Devices Per Transmission

OFDMA (Orthogonal Frequency Division Multiple Access) is the single most important technology in WiFi 6. It changes how routers divide up wireless channel capacity among connected devices.

In WiFi 5 and earlier, the router transmits to one device at a time on a given channel. Even if a device only needs a tiny amount of data (a smart thermostat reporting the temperature), the router dedicates an entire transmission opportunity to it. This wastes channel time, especially on networks with many low-bandwidth devices.

OFDMA divides a channel into smaller sub-channels called Resource Units (RUs). The router can assign different RUs to different devices within a single transmission. A smartphone downloading a large file gets more RUs while the thermostat gets a small allocation, all in the same time slot. This is similar to how a cargo plane is more efficient when carrying packages for multiple recipients rather than flying full-sized for each delivery.

The result is dramatically reduced latency and improved throughput on busy networks. Devices spend less time waiting for their turn to communicate. In testing, OFDMA reduces average latency by 75% or more in high-density environments compared to WiFi 5 networks.

MU-MIMO Improvements

MU-MIMO (Multi-User Multiple-Input Multiple-Output) was introduced in WiFi 5 Wave 2, but WiFi 6 expands it significantly. WiFi 5 only supported downlink MU-MIMO (router to devices) with up to four simultaneous streams. WiFi 6 adds uplink MU-MIMO (devices to router) and increases the maximum to eight simultaneous streams.

Downlink MU-MIMO means the router can send data to multiple devices at the same time instead of cycling through them one by one. Uplink MU-MIMO means multiple devices can transmit data to the router simultaneously. This bidirectional improvement is particularly noticeable during video calls, online gaming, and any scenario where devices are both sending and receiving data frequently.

An eight-stream WiFi 6 router can theoretically communicate with eight devices in parallel. In practice, the number of simultaneous streams depends on the router’s antenna configuration and the devices’ capabilities. A 4x4 router handles four simultaneous MU-MIMO streams. Consumer WiFi 6 routers typically support four to eight streams.

BSS Coloring: Reducing Neighbour Interference

BSS Coloring (Basic Service Set Coloring) solves a problem that plagues anyone living in an apartment building or dense neighbourhood. In WiFi 5 and earlier, when your router detects a transmission from a neighbouring network on the same channel, it pauses and waits. This “defer” behaviour is polite but wasteful. Your router sits idle even though the neighbouring transmission is not relevant to your network.

WiFi 6 assigns a colour (a numerical identifier from 1 to 63) to each BSS (essentially each WiFi network). When your router detects a signal from a different-coloured network, it can transmit simultaneously instead of waiting. Only signals from the same colour require deference.

This is a significant improvement in environments with many overlapping WiFi networks. Apartment buildings, office floors, and convention centres see meaningful throughput improvements from BSS Coloring alone. In a test scenario with 20 overlapping networks, BSS Coloring improved per-network throughput by up to 50% compared to WiFi 5 behaviour.

The technology works automatically. You do not need to configure it. The router assigns its BSS colour during startup and adjusts if it detects too many conflicts.

Target Wake Time (TWT)

Target Wake Time is a WiFi 6 feature designed specifically for battery-powered devices. TWT allows the router and a device to negotiate a schedule for when the device will wake up to send and receive data.

Before TWT, WiFi devices had to periodically wake up and check with the router to see if any data was waiting for them. This constant polling drained battery life, especially on IoT devices that only need to communicate a few times per hour.

With TWT, a smart sensor can tell the router: “I will wake up at 10-minute intervals. Hold my data until then.” Between those intervals, the device’s WiFi radio is completely off, consuming almost no power. The router buffers any incoming data and delivers it during the next scheduled wake window.

For smartphones and laptops, TWT provides modest battery improvements because these devices are already optimised for power management. For IoT devices like smart home sensors, leak detectors, and door sensors that run on batteries, TWT can extend battery life substantially.

Real-World Speed Improvements

WiFi 6 increases the maximum theoretical throughput to 9.6 Gbps (compared to WiFi 5’s 6.9 Gbps), but this number is largely marketing. No single device comes close to that figure.

The real speed gains come from improved modulation (1024-QAM vs WiFi 5’s 256-QAM) and better channel utilisation through OFDMA. 1024-QAM encodes 10 bits per symbol instead of 8, a 25% increase in data density. This means more data per transmission, which translates to faster speeds at any given distance.

In controlled testing, a single WiFi 6 device connecting to a WiFi 6 router typically sees 20-40% faster throughput compared to a WiFi 5 device on a WiFi 5 router at the same distance. The improvement is more pronounced at medium range (one or two rooms away) where signal quality is good but not perfect.

The dramatic improvements appear on busy networks. A WiFi 6 router serving 20 devices maintains per-device throughput far better than a WiFi 5 router serving the same load. Where WiFi 5 might drop individual device speeds to 20-30 Mbps under heavy load, WiFi 6 keeps them at 50-100 Mbps or more.

Should You Upgrade from WiFi 5?

The answer depends on your specific situation, not on WiFi 6 being “newer and better.”

Upgrade if: You have 15 or more WiFi devices. You live in an apartment building with many competing networks. You have smart home devices on batteries. You frequently have multiple people streaming, gaming, and video calling simultaneously. Your current WiFi 5 router is more than four years old.

Wait if: You have fewer than 10 devices. Your current WiFi 5 router covers your home adequately. You live in a low-congestion environment (suburban house with no close neighbours). Your internet plan is under 200 Mbps, meaning the ISP connection is the bottleneck, not the WiFi.

If you do upgrade, consider WiFi 6E for the additional 6 GHz band. The 6 GHz spectrum is uncrowded and provides the best real-world performance for devices that support it. WiFi 6E routers cost slightly more than WiFi 6 models but offer a significant practical advantage, especially in congested environments.