Final approval of the 802.11be standard may only be expected in December 2024, but that doesn’t mean the Wi-Fi Alliance is serious about creating a Wi-Fi 7 certification program.
At 2024 CES, the program was officially announced, with silicon-based products from Broadcom, Intel, Mediatek, and Qualcomm earning the Wi-Fi CERTIFIED 7 tag. Broadcom, Mediatek and Qualcomm have already experienced his two generations of Wi-Fi 7 products, and it is expected that the final draft status of Wi-Fi 7 will be confirmed eventually. This also allows for faster deployment on the client side. The main features of Wi-Fi CERTIFIED 7 are based on the work of the IEEE 802.11be Extremely High Throughput (EHT) working group.
The introduction of 6 GHz support in Wi-Fi 6E in some regions opens up channels that were previously unavailable for in-home wireless use. Wi-Fi CERTIFIED 7 brings support for 320 MHz channels. These ultrawide channels are only available in the 6 GHz band.
These channels deliver the high throughput promised by Wi-Fi CERTIFIED 7. However, the unavailability of 6 GHz in many regions has proven to be a deterrent for client device vendors. Many of these companies don’t want to spend extra money on features that aren’t available in all regions. Many client devices, especially on the smartphone side, may initially ship without support for 320 MHz channels.
Multilink operations (MLO) is another technique to increase the available bandwidth for a single client. Wi-Fi CERTIFIED 7 allows clients to connect to access points over multiple bands simultaneously. It also improves connection reliability.
Wi-Fi 7 also introduces 4K QAM, which can encode up to 12 bits per symbol. This represents a 20% increase in spectral efficiency compared to Wi-Fi 6 (which only requires support for 1024 QAM).
Dense constellations require very sophisticated circuitry on both the transmitter side (linear power amplifier) and receiver side (to avoid error-free symbol decoding). These are some of the advancements found in Wi-Fi CERTIFIED 7 devices.
Other important updates in Wi-Fi CERTIFIED 7 include support for 512 compressed block ACKs, multiple resource units to a single station/client, and triggered uplink access.
802.11n introduces the concept of block ACKs at the MAC layer, allowing the receiver to acknowledge multiple radio “frames” (more precisely MAC protocol data units or MPDUs) in one response. The ACK indicates the missing MPDU, if any, in the previously transmitted set. In Wi-Fi 6, his limit on the number of MPDUs per block ACK was 256. Wi-Fi 7 increases this to 512. Distributing this communication improves resource utilization.
Wi-Fi 6 introduces the concept of resource units to the OFDMA scheme, which divides the radio channel into smaller frequency allocations called RUs. These allow small packets to be sent to multiple users simultaneously. In Wi-Fi 6, each user can only get one RU. Wi-Fi 7 improves efficiency by enabling non-contiguous RU allocation to a single user.
Benefits of multiple RU allocations to a single user (Source: Mediatek)
Wi-Fi 6 introduced the concept of triggered uplink access, allowing clients to simultaneously send data to access points in an independent manner. This transmission is synchronized by the AP sending a trigger frame containing resource unit allocation information for each client. Wi-Fi 7 further optimizes this scheme for QoS requirements and delay-sensitive streams.
Meanwhile, the 802.11 working group has already begun the groundwork for Wi-Fi 8. 802.11 billion (Ultra High Reliability or UHR) aims to increase the resiliency of high-speed Wi-Fi networks by enabling multi-link distributed operation. It realizes cooperation between multiple access points, cooperation between multiple access points, power saving functions on the access point side, etc.
802.11 Billion (EHR) Timeline: Wi-Fi 8 Deployment 2027-2028? (Source: What Will Wi-Fi 8 Be? A Primer on IEEE 802.11bn Ultra Reliable [PDF])
The Wi-Fi Alliance expects a wide range of application scenarios for Wi-Fi 7 now that it has been certified.
These include mobile gaming, video conferencing, industrial IoT, automotive, multi-user AR/VR/XR, immersive e-training modules, and other use cases. Wi-Fi 6 brought many technological advances to Wi-Fi, and Wi-Fi 7 brings even more to it. Unfortunately, AR/VR/XR has been trying to break into the mainstream for quite some time without much success. This is one of the major single-client use cases that can benefit from features such as Wi-Fi 7’s MLO.
Advances in spectral efficiency over the past few generations have greatly contributed to enterprise adoption. These are scenarios where a single access point needs to serve a large number of clients while maintaining acceptable QoS. The user experience has also been improved in MDUs (Multi-Dwelling Units/Multi-Dwelling Units) where multiple wireless networks are intertwined. That said, vendors are still searching for the ideal single-client scenario to unlock the benefits of Wi-Fi 7. Wired speeds have been largely stagnant for the past decade, with few ISPs offering gigabit speeds at affordable prices. Over a wide enough range. Both wired and wireless technologies must evolve in parallel to benefit consumers and engage them with compelling use cases. As it stands, the pace of advancement in Wi-Fi has significantly outpaced wired networks over the past 20 years.
