First look at Wi-Fi 8 - same peak and better actual speeds

Although Wi-Fi 8 is still some time away from release, MediaTek's wireless division has shared some insights. For the first time, the update will prioritize effective bandwidth over peak speed.

The Wi-Fi 8 standard, currently referred to as IEEE 802.11bn Ultra High Reliability, will replace Wi-Fi 7, which has yet to be officially recognized. The final specifications for Wi-Fi 8 are expected around September 2028. The main principle of the new standard is to focus on effective bandwidth rather than peak performance.

MediaTek believes that Wi-Fi 8 will be identical to Wi-Fi 7 in several key aspects: the maximum physical level speed (PHY) will remain the same at 2880 Mbps x8, or 23 Gbps. It will utilize the same frequency bands (2.4, 5, and 6 GHz) and the same 4096 QAM modulation with a maximum channel bandwidth of 320 MHz.

Of course, a Wi-Fi 8 router will not achieve a throughput of 23 Gbps. According to MediaTek, the actual peak throughput in an ideal environment is only 80% of the hypothetical maximum capacity, and real-world results may be significantly lower.

In simple terms, Wi-Fi 8 will provide the same throughput as Wi-Fi 7, employing the same channels and modulation. Each Wi-Fi standard has been backward compatible with its predecessors. However, Wi-Fi 8 will change how client devices interact with multiple access points, offering several enhancements.

Coordinated Spatial Reuse (Co-SR) — This technology was first implemented in Wi-Fi 6 as spatial reuse. It encountered issues related to differences in transmission power between the access point communicating with a nearby device and the simultaneous connection to a second access point located further away. If the first access point reduced its power to communicate with the nearby device, the distant access point would not receive the signal.

According to MediaTek, Co-SR in Wi-Fi 8 is a "mature" technology that addresses this limitation, allowing access points to coordinate their output power. Preliminary tests have shown that Co-SR can enhance overall throughput by 15-25%.

Dynamic Sub-Channel Operation (DSO) — It is known that the latest devices support the newest wireless standards. However, some possess better Wi-Fi antennas that deliver higher throughput. Previously, this information was sent to the router and stored there. While this is not an issue under most conditions, when several different devices were downloading the same file, DSO created a dynamic scenario to allocate an additional sub-channel for the faster device.

The distinction between the old approach and DSO in Wi-Fi 8 is that the access point will be able to better route this traffic, improving outcomes for faster devices. MediaTek believes that DSO can increase throughput by 80%.

Improved Speed Distribution via MCS Index — The modulation coding scheme of Wi-Fi helps the router determine the optimal connection speed for error-free data transmission. If the throughput slows down while moving, it is partially due to the device and router "negotiating" the speed at which the device should operate.

MediaTek argues that the step "down to a lower speed" is too large and that finer gradations should be introduced. Smaller MCS steps could increase overall data rates by 5-30%.

The development of wireless standards typically takes about six years, but hardware manufacturers are pushing for faster implementation of new technologies. Wi-Fi 7 devices are expected to roll out from late 2023, even though the standard is not yet official. This is partly because the IEEE committee rarely makes significant changes between the approval of drafts and the final standard. The first Wi-Fi 8 devices are anticipated to arrive in early 2028.

Source: PCWorld, citing a MediaTek document.