At the 2024 US Consumer Electronics Show (CES), the program officially announced that products based on Broadcom, Intel, Mediatek and Qualcomm chips will receive the Wi-FiCERTIFIED7 certification label. Among them, Broadcom, Mediatek and Qualcomm have experienced the development of two generations of Wi-Fi7 products, and finally saw Wi-Fi7 exit the draft status, which is full of hope.
In this way, clients can also adopt Wi-Fi 7 more quickly. The main features of Wi-Fi CERTIFIED 7 are based on the efforts of the IEEE802.11beEHT (Extremely High Throughput) working group.
Wi-Fi 6E introduces 6GHz support in select areas, opening up channels hitherto unavailable for home wireless use. Wi-FiCERTIFIED7 supports 320MHz channels. These ultra-wide channels are only available in the 6GHz band.
The high throughput promised in Wi-FiCERTIFIED7 is provided by these channels. However, the lack of access to 6GHz in many areas has proven to be an obstacle for client equipment vendors. Many of these companies don't want to spend extra money for features that aren't available in all regions. Many client devices (especially smartphones) may not support 320MHz channels when shipped from the factory.
Multi-link operation (MLO) is another technique for increasing the bandwidth available to a single client. Wi-FiCERTIFIED7 allows clients to connect to access points over multiple frequency bands simultaneously. It also improves connection reliability.
Wi-Fi 7 also introduces 4KQAM, which allows encoding of up to 12 bits per symbol. This means that the spectrum efficiency is 20% higher than Wi-Fi6 (which only needs to support 1024QAM).
To do this requires extremely complex circuitry at the transmitter (linear power amplifier) and receiver (to avoid incorrect symbol decoding). These are some of the advanced technologies we can see in Wi-FiCERTIFIED7 devices.
Some other important updates for Wi-Fi CERTIFIED 7 include support for 512 compressed block acks, multiple resource units for a single station/client, and triggered uplink access.
802.11n introduced the concept of blockacks at the MAC layer, whereby the receiver can acknowledge multiple wireless "frames" (MAC Protocol Data Units or more accurately MPDUs) in one response. If there are missing MPDUs, ack will be displayed in the previously transmitted data set. In Wi-Fi 6, the number of MPDUs acknowledged per block is limited to 256. In Wi-Fi 7, this limit is increased to 512. Decentralizing this communication allows for better utilization of resources.
Wi-Fi6 introduces the concept of resource units in the OFDMA scheme, dividing radio channels into smaller frequency allocations, called RUs. These resource units allow the transmission of small packets to multiple users simultaneously. In Wi-Fi6, each user only gets one RU. Wi-Fi 7 improves efficiency by allocating non-contiguous RUs to individual users.
Wi-Fi 6 introduces the concept of triggered uplink access, allowing clients to simultaneously send data back to the access point in an independent manner. Access points synchronize transmissions by sending trigger frames containing resource unit allocation information for each client. Wi-Fi7 further optimizes this solution for QoS requirements and delay-sensitive data flows.
At the same time, the 802.11 working group has begun the basic work of Wi-Fi8. 802.11bn (Extreme High Reliability or EHR) is designed to bring more resiliency to high-speed Wi-Fi networks by allowing multi-link operation distributed across multiple access points, coordination between multiple access points, and power saving features on the access point side.
At present, the Wi-Fi Alliance has passed the certification, and Wi-Fi7 is expected to have a wide range of application scenarios.
These applications include mobile gaming, video conferencing, industrial IoT, automotive, multi-user AR/VR/XR, immersive electronic training modules, and other use cases. Wi-Fi6 has brought many technological advancements to Wi-Fi, and Wi-Fi7 has taken it to the next level. Unfortunately, AR/VR/XR have been trying to break into the mainstream market for quite some time, but with little success. It is one of the major single client use cases that can benefit from features like MLO in Wi-Fi 7.
Advances in spectral efficiency over the past few product generations have gone a long way toward enterprise deployments. In this case, a single access point must be used to serve a large number of customers while maintaining acceptable QoS. In multi-dwelling units/apartments (MDUs), where multiple wireless networks interfere with each other, the user experience is also improved. Still, providers are still looking for the ideal single-client scenario to take advantage of Wi-Fi 7 -- speeds on wired networks have largely stagnated over the past decade, with few ISPs offering gigabit speeds at a reasonable price or at a large enough range. Wired and wireless technologies must evolve in tandem to deliver benefits to consumers and attract them with attractive use cases. Judging from the current situation, the development speed of Wi-Fi has greatly exceeded that of wired networks in the past few decades.