Do you know which phones support Wi-Fi 7?
After all, popular models such as Xiaomi 13 series and honor Magic5 series, although the mobile phone supports the Wi-Fi 7 protocol, there is not much publicity, and even the product details page is not mentioned.
*OnePlus Ace 2 Pro promotional image
In fact, it is very simple to determine whether a mobile phone supports Wi-Fi 7 protocol, if the mobile phone SoC is Qualcomm Snapdragon 8 Gen2 or MediaTek Dimensity 9200 or above, it supports Wi-Fi 7 protocol, but OTA upgrade system version may be required.
Old Fox remembers that when the mobile phone first supported the Wi-Fi 6 protocol, various mobile phone manufacturers were still working hard to promote it, but now it is Wi-Fi 7's turn, but it is cold.
On the one hand, there are too many selling points of mobile phone technology now, and the technical upgrade of Wi-Fi is already "Mrs. Cow".
Another reason may be the landing of Wi-Fi 7, which only solicited Wi-Fi 7 device approval in early June this year, and ended on July 1.
In other words, the solicitation of domestic Wi-Fi 7 device approval opinions has only been over for less than two months, and it has not yet entered the stage of implementation.
Like Xiaomi's 10 Gigabit router, although the hardware reserves space for Wi-Fi 7, it is also waiting for the policy, and the subsequent support can be updated.
Although Wi-Fi 7 has not yet become popular, it is just the right time to introduce the relevant knowledge of Wi-Fi 7 to friends.
Of course, if you are not interested in technology, you can directly pull down the end of the article and see the conclusion.
Wi-Fi 7 technology improvements
Wi-Fi 7, that is, the 7th generation of Wi-Fi network technology, the technical standard is the aforementioned "IEEE 802.11be", on the official website of the Wi-Fi Alliance, the standard "IEEE 802.11be" is being improved.
Due to the development of VR, metaverse, remote office, 4K video and other applications, the network requirements have further increased, Wi-Fi 6 has been unable to meet the requirements of these applications for data transmission speed and network latency, so IEEE and Wi-Fi alliances are rapidly promoting the development of Wi-Fi 7.
The figure below shows a comparison of Wi-Fi 7 and Wi-Fi 6 technical standards.
Compared with Wi-Fi 6, the maximum transmission speed of Wi-Fi 7 can reach 46Gbps (domestic 30Gbps), which is close to five times that of Wi-Fi 6.
Wi-Fi 7 will support more frequency bands, including 2.4GHz, 5GHz, 6GHz, before that, Wi-Fi 6 supported both 2.4GHz and 5GHz bands, and Wi-Fi 6E only supported 6GHz bands (Wi-Fi devices are backward compatible).
However, due to the allocation of frequency bands in different regions, the 6GHz band supported by Wi-Fi 7 will vary at home and abroad.
For example, the United States, South Korea, and Brazil split the entire 6GHz band (5.925 - 7.125GHz) to Wi-Fi 6E and Wi-Fi 7.
Some countries allocate the 6GHz low-frequency band (5.925 - 6.425GHz) to Wi-Fi, and the remaining frequency band (6.425 - 7.125GHz) is allocated to IMT (International Mobile Communications, including 5G/6G systems), such as within the European Union, Japan and Australia and other countries.
Considering the future development of 5G and 6G, the mainland has allocated the 6.425 - 7.125GHz band to IMT, therefore, this band will not be used for Wi-Fi, and the 6GHz low band (5.925 - 6.425GHz) is not allocated to Wi-Fi, temporarily retained, leaving room for subsequent development.
That is to say, domestic Wi-Fi 7 may eventually not support the 6G band, which can be confirmed by the frequency band given in the Ministry of Industry and Information Technology's solicitation of Wi-Fi 7 device approval opinions.
Due to the lack of 6GHz frequency band, there are not enough spectrum bandwidth resources to accommodate 320MHz channels, therefore, domestic Wi-Fi 7 can only support 240MHz channels, and the maximum transmission speed is also limited to 30Gbps, which can theoretically meet the needs of metaverse, VR, remote office, 4K video and other applications.
Why is the channel so important?
In wireless transmission, the basic channel is 20MHz, if the wireless transmission is compared to freight, then 20MHz is the basic single lane, in order to improve the freight speed, so the two adjacent 20MHz merged, dual lane, that is, 40MHz channel, and so on, there is an 80MHz channel and a 160MHz channel.
Wider channels can obtain higher information transmission capabilities.
In the figure above, there are only three consecutive non-overlapping 20MHz channels in the 2.4GHz band, and two consecutive non-overlapping 20MHz channels can be bound to 40MHz channels (this is generally not recommended in the 2.4GHz band).
The 5GHz band has up to 13 contiguous non-overlapping 20MHz channels and up to 160MHz channels under the Wi-Fi 5 and Wi-Fi 6 standards.
6GHz has abundant spectrum bandwidth resources, so it can support 320MHz channels, and even in the case of 6G spectrum division in the United States, there are 1200MHz spectrum bandwidth resources.
Modulation method, Wi-Fi 7 has also been improved, supporting 4096QAM, which means that the information supported by each modulation symbol has increased from 10bit to 12bit under the previous 1024QAM modulation, and the amount of information transmitted is more.
In addition, the number of Wi-Fi 7 spatial streams has also expanded from 8 to 16 in Wi-Fi 6, which means that an AP can transmit data to 16 receivers at the same time (an STA side can have multiple receivers). 2x faster spatial streaming.
The above is the technical upgrade of Wi-Fi 7 based on Wi-Fi 6, and there are three new technical highlights on Wi-Fi 7 to enable devices to transmit data faster and more stably under the Wi-Fi 7 protocol.
Multilink Transport Technology (MLO)
On previous Wi-Fi 6 devices, although 2.4GHz and 5GHz frequency bands were provided, the device could only transmit on one band when transmitting data, and if the conditions changed, it jumped to another frequency band for transmission, the process is left in the figure below.
The multi-link transmission of Wi-Fi 7 can transmit data in two frequency bands at the same time as shown on the right side of the figure above, and the transmission mode is divided into two modes.
One is multi-transmit single receipt, that is, multiple frequency bands (2.4GHz, 5GHz, 6GHz) on the AP side send the same data to the receiver at the same time, and the system automatically selects the fastest frequency band data, and if the frequency band is interfered, the system accepts data from other frequency bands.
*Source: @Xunjie Network video
This method can improve the stability of data transmission.
Another mode is multi-transmit and multi-receive, that is, one piece of data is split into three copies, sent simultaneously through three frequency bands, and the data is combined after receiving it.
*Source: @Xunjie Network video
The multi-transmit and multiple-receive mode can increase the speed of data transmission.
Multi-Resource Unit (MRU)
On Wi-Fi 5, each channel can only send information to one receiver per unit of time, in order to improve utilization, on Wi-Fi 6, the concept of Resource Unit (RU: Resource Unit) is introduced.
*OFDM on Wi-Fi 5 and OFMDA on Wi-Fi 6
Through orthogonal frequency-division multiple access (OFDMA) technology, a 20MHz channel can be divided into 256 subcarriers, of which 242 are effective subcarriers, and the Wi-Fi Alliance stipulates that the minimum resource unit is 26 subcarriers, so the effective subcarriers of different RUs within a channel can be 26 (26-tone RU), 52 (52-tone RU), 106 (106-tone RU), and 242 (242-tone RU).
*Schematic diagram of OFDM technology, on which OFDMA technology is built
In the Wi-Fi 6 standard, the Wi-Fi Alliance specifies the number of subcarriers of an RU, mainly including: 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, 996-tone RU, 1992-tone RU, a user can only correspond to one RU.
In Wi-Fi 7, multi-resource units (MRU: Multi-RU) are supported, that is, a user can correspond to a combination of multiple RUs, such as a combination of 26-tone RU and 52-tone RU, or a combination of 484-tone RU and 996-tone RU.
For example, there are three users at the same time within 20MHz, one user is assigned to 106-tone RU, the other two users are assigned to 52-tone RU, and the remaining 26-tone RU can be reassigned to the former, so that it can receive two RUs, reaching 106-tone RU + 26-tone RU, which improves resource utilization and information transmission speed.
*RU division of different frequency bands
But not any RU can be combined, and the Wi-Fi 7 protocol divides RUs into two categories:
小部 RU:26-tone RU,52-tone RU,106-tone RU;
大部 RU:242-tone RU,484-tone RU、996-tone RU、1992-tone RU。
The Wi-Fi Alliance stipulates that only the same RUs can be combined, small RUs and small RU combinations, and large RU and large RU combinations, such as 1992-tone RU and 996-tone RU combinations, which is equivalent to a 160MHz channel and 80Mhz channel combination.
Preamble (Puncturing)
The purpose of the leading code punching technology is the same as that of the multi-resource unit, which is to improve the utilization rate of the channel, but the leading code punching is more to restore the use of channel utilization in the case of interference.
As mentioned in the previous channel section, the basic channel is 20MHz, through channel bundling, it can be composed of 40MHz channel, 80MHz channel, 160MHz channel, but there are main channels and auxiliary channels when bundling, and its distribution principle is as follows:
Main channel 20MHz and 20MHz combination: 20MHz (primary) + 20MHz (auxiliary);
Combined into a main channel 40MHz and then combined: 40MHz (primary) + 40MHz (auxiliary);
Combine into a primary channel of 80MHz and then combine: 80MHz (primary) + 80MHz (auxiliary).
Before Wi-Fi 7, once the auxiliary channel in the combination is interfered, it cannot be combined into a wider primary channel, for example, the 20MHz auxiliary channel is interfered with and cannot be combined with the 20MHz main channel, then the remaining 40MHz auxiliary channel and 80MHz auxiliary channel cannot be used, resulting in waste of channel resources.
The preamble code punching solves this problem, which can shield the disturbed 20MHz auxiliary channel without affecting the main channel to form a wider channel, and the 20MHz main channel can still form a 60MHz channel with the 40MHz auxiliary channel, and then form a 140MHz channel with the 80MHz auxiliary channel.
The preamble code punching greatly improves the anti-interference ability of information transmission, and can still quickly transmit information even in the interference environment.
At last
The above is about the relevant technology of Wi-Fi 7, and multiple technology upgrades make it faster, lower latency, and more stable.
According to Huawei's previous tests with the Xiaomi Mi 13 Pro (well, isn't it incredible?). But it did happen... ), Xiaomi 13 Pro that supports the Wi-Fi 7 communication protocol standard has a transmission speed of 4.3Gbps in the Wi-Fi 7 environment, which is twice that of the Wi-Fi 6 environment; At the same time, the delay is within 4ms, while the delay in Wi-Fi 6 environment is about 10ms.
For the sake of mobile communication development strategy, the Ministry of Industry and Information Technology allocated the high frequency band of the 6G band to IMT, and the low frequency band of 6G was temporarily not allocated, so the domestic Wi-Fi 7 was temporarily unavailable for 6G band, and the performance was castrated, and the future was not clear.
It is precisely because of this that mobile phone manufacturers and router manufacturers retain the upgrade space of Wi-Fi 7, but they are not willing to publicize too much, after all, the advertised functions are different from subsequent standards, which has become false propaganda.
But the domestic Wi-Fi 7 standard is about to land, and it is not far from us.
Resources:
Ruijie Network: The difference between Wi-Fi 7 and Wi-Fi 6 is understood
ElecDeveloper: Hello Wi-Fi 6
IT House: Wi-Fi 7 domestic standard is about to land! The Ministry of Industry and Information Technology solicited equipment approval opinions, and the measured network speed reached 4.3Gbps
Internet of Things Think Tank: Fixed! The Ministry of Industry and Information Technology divides the 6GHz spectrum, is there still a chance for Wi-Fi 7?
Intel：WiFi7，The Next Era In Wireless
Electronicsnotes：Understanding IEEE 802.11be Wi-Fi 7
IEEE：What Is Wi-Fi 7？
Editor: Mu Yi