In January 2020, Wi-Fi Alliance officially announced the opening of 6 GHz (5 925 MHz–7 125 MHz) and gave it a new name Wi-Fi 6E. In April of the same year, the US FCC (Federal Communications Commission) also voted to approve it. The 6 GHz spectrum is opened as an unlicensed band and allowed to be used by Wi-Fi. Wi-Fi has officially entered the "tri-band" era, in addition to Wi-Fi 6 and the 2.4 GHz used by the previous generation of Wi-Fi. As well as the 5 GHz band, Wi-Fi 6E can also operate in the 6 GHz band.

 

In mid-2021, some mainstream Wi-Fi equipment manufacturers on the market began mass production and sales of Wi-Fi 6E products. Starting from 2022, Wi-Fi 6E has become the mainstream specification on the market, regardless of the bidding of European and American operators. The solution is still high-end home Wi-Fi network equipment such as home routers, Mesh, wireless signal extenders and even high-specification laptops, etc. have included Wi-Fi 6E in the basic specifications. Just as everyone is gearing up to welcome Wi-Fi When the 6E era arrives, Wi-Fi 7 has occupied most of the Wi-Fi industry and technology-related pages at lightning speed. Why does Wi-Fi 7 attract most people''s attention? What new technological innovations does Wi-Fi 7 have compared to previous Wi-Fi technologies? What''s its current status? Below we will discuss these issues.

 

What is Wi-Fi 7?

Before we discuss Wi-Fi 7, let’s review the evolution and technical highlights of past generations of Wi-Fi specifications. At the end of 2018, in order to simplify the complex naming of Wi-Fi standards, Wi-Fi Alliance officially renamed the original 802.11ax to Wi-Fi 6. At the same time, retroactively, the existing 802.11ac was changed to Wi-Fi 5. , 802.11n was renamed Wi-Fi 4

 

In 2020, Wi-Fi 6E came out immediately after Wi-Fi 6. Wi-Fi 6E opened the 6 GHz frequency band for Wi-Fi to use. Since then, Wi-Fi has officially entered the "true tri-band" architecture (2.4 GHz/5 GHz/6 GHz Tri-Band architecture)

 

The Wi-Fi standard currently remains at Wi-Fi 6E. Scientists, scholars and members of IEEE and Wi-Fi Alliance are discussing and proposing technical specifications and MRD (Marketing Requirements Document) related to Wi-Fi 7. According to Wi-Fi Fi Alliance''s latest meeting minutes, the latest MRD document has been officially approved by WFA in March 2022, and the IEEE working group will also publish the latest IEEE P802.11be™/D2.0 standard draft in March 2022 document.

In addition to improving bandwidth availability, Wi-Fi 7 APs that support the MRU function can significantly improve the latency caused by simultaneous transmission scenarios by multiple users.

 

For example, assume that 4 users require to transmit data of different lengths at the same time. The original data lengths to be transmitted by user 1 to user 4 are 2:2:3:1 respectively. Based on the Wi-Fi 5 AP architecture, in SU(Single User) multi-task transmission mode, it takes a total of 451 μs to transmit all data of 4 users; under the Wi-Fi 6 architecture, OFDMA-RU provides a more efficient transmission method. Since it does not support MRU, It needs to be transmitted in two times. The data length of the first transmission is 1:1:1:1 (RU-484 ton for each user), and the data length of the second transmission is 1:1:2:0 (RU-484 tone for user 1 and user 2; RU-996 tone for user 3), it takes a total of 406 μs to transmit all the data of 4 users; under the Wi-Fi 7 architecture, MRU provides the most efficient transmission method, through different The combination of RU size and the previously mentioned Preamble Puncturing only takes 302 μs to complete the transmission of all users.

 

Based on the comparison of end-to-end delays when four users transmit simultaneously under different Wi-Fi specifications, Wi-Fi 7 APs that support MRU can allocate RUs in a more efficient way to shorten the point-to-point delay. Compared with Wi-Fi 5, the delay time can be reduced by 33%; compared with Wi-Fi 6, the delay can be reduced by 25%.

 

Multi-AP Operation

Multi-AP cooperative operation (Multi-AP Operation or Multi-AP Coordination), like the MLO and MRU mentioned before, is a new technology that Wi-Fi 7 will adopt. In fact, technologies similar to Multi-AP Operation have been around since Wi-Fi 5 has already appeared, and it has an easy-to-understand name - "Wi-Fi Mesh". At that time, Wi-Fi Mesh technology was mainly provided by chip manufacturers, such as Qualcomm''s Wi-Fi SON, Broadcom SmartMesh, Therefore, it is inevitable to encounter compatibility issues. Later, the Wi-Fi Alliance defined the standard specification of EasyMesh™ and standardized the Mesh protocol to solve the problem of Mesh compatibility. Wi-Fi Mesh is just the predecessor of Multi-AP Operation. As mentioned in the previous article, most of the previous Wi-Fi Mesh were special functions defined and developed by Wi-Fi chip suppliers, such as mesh network controllers and agents. (Mesh Controller and Agents), Wi-Fi Smart Roaming (Wi-Fi Smart Roaming), etc. In today''s 802.11 communication framework (802.11 Protocol Framework), there is not much emphasis on the collaborative operation between AP and AP. Wi-Fi 7, IEEE specifically proposed the specification of Multi-AP Operation to optimize channel selection and load adjustment between APs to achieve the most efficient usage and allow Wi-Fi wireless resources to be allocated fairly and balancedly .

 

The most important key technology for multi-AP cooperative operation of Wi-Fi 7 is the coordinated scheduling between APs, which must take into account both the time and frequency dimensions as well as inter-cell interference suppression coordination. |coordination; ICIC) and MIMO distribution, etc., the lower the mutual interference between APs, the higher the quality of communication and the availability of wireless signals will be.

 

Multi-AP Operation has the following deployment methods, namely C-OFDMA (Coordinated Orthogonal Frequency Division Multiple Access), CSR (Coordinated Spatial Reuse), C-CDMA (Coordinated Collision Division Multiple Access), CBF (Coordinated Beamforming) and JXT (Joint Transmission)

 

Wi-Fi equipment manufacturers can decide the Multi-AP Coordination method based on different Wi-Fi network architectures and configurations. The five Multi-AP Coordination deployment methods mentioned above are divided into media access layer driver (MAC-Driven). ) (Figure 16) or driven by the physical layer (PHY-Driven) (Figure 17). The coordination method of PHY Driven is relatively easy to implement and the technical threshold is relatively low. The coordination method of MAC Driven is technically more complex. It requires higher construction costs, but the effect is relatively significant.

 

 

 

WIFI 7 Product DR9574--IPQ9574

 

Qualcomm IPQ9574 Quad-Core ARM-A73 @ 2.2GHz processor ‘Alder’ Series