In this post, we will provide a high-level overview of Wi-Fi 7 (based on IEEE 802.11be, also known as
EHT
–
E
xtremely
H
igh
T
hroughput). IEEE began working on 802.11be in early 2019, with the following key objectives in mind.
E
xtremely
H
igh
T
hroughput (maximum throughput of 30 Gbps)
Reduce transmission latency and jitter
Increase transmission reliability
It is important to distinguish between Wi-Fi 6, Wi-Fi 6E, and Wi-Fi 7 certifications before diving into the details of Wi-Fi 7 features. At the time of the 802.11ax development (2014-2020), only the 2.4GHz and 5GHz spectrums were available for Wi-Fi. Hence, the Wi-Fi Alliance’s Wi-Fi 6 certification (introduced in 2019 based on a draft version of 802.11ax) covers 802.11ax deployment across these two frequency spectrums. When the U.S. allocated the 6GHz band for Wi-Fi in late 2020, the Wi-Fi Alliance introduced Wi-Fi 6E in 2021, which validates 802.11ax deployment in the 6GHz band. Wi-Fi 7 works across all three spectrums, and the availability of the 6GHz frequency varies depending on the country you are in. (refer to this page from Wi-Fi Alliance for global 6GHz deployment status).
Note that a device certified for Wi-Fi 7 does not necessarily support all three spectrums
. Countries like China do not have the 6GHz spectrum available for Wi-Fi, so Wi-Fi 7 certified devices in that country operate only in the 2.4GHz and 5GHz spectrums.
Since Wi-Fi 7 is built on OFDMA, which was introduced with 802.11ax (Wi-Fi 6), it’s useful to recap the features of Wi-Fi 6. Here is an infographic from the Wi-Fi Alliance highlighting those features. OFDMA was the key feature that helps improve the efficiency of Wi-Fi communication. Hence, 802.11ax is also known as
H
igh
E
fficiency (
HE
). There are other useful features like
Target Wake Time
,
BSS Color
introduced in 802.11ax. However, those were not widely deployed by vendors as those were not mandatory requirements to get Wi-Fi 6 certification.
It is important to note that Wi-Fi 6E is specifically about OFDMA (in the 6GHz spectrum) and is not backward compatible with OFDM (used in 802.11a, 802.11n, and 802.11ac)
. In other words, if you are using a 6GHz client, you will always use OFDMA, whereas if your station (STA) is on the 2.4GHz or 5GHz bands, you can connect using either OFDMA or OFDM (AP determine which technology to use depending on their own implementations).
Here is a similar infographic from Wi-Fi Alliance about Wi-Fi 7 features. It is important to note that Wi-Fi 7 is supported across all 3 radio spectrums (2.4/5/6 GHz). Wi-Fi 7 is using OFDMA which was introduced in 802.11ax.
[
MLO
] One of the key features of Wi-Fi 7 is
M
ulti-
L
ink
O
peration (
MLO
), which allows a station to associate with an AP across multiple bands. This does not mean the client will always communicate across all those links simultaneously (you can get higher throughput when the station can do that). However, the client can switch between these links with minimal effort, which helps reduce latency for applications while increasing the reliability of communication. Those are the key objectives of 802.11be.
There are five different MLO modes introduced in 802.11be. Though MLO feature is mandatory for Wi-Fi 7 certification, support for all of these modes is not required.
MLSR
: Multi-Link Single Radio (
mandatory for APs and Clients
)
EMLSR
: Enhanced Multi-Link Single Radio (
optional for APs and Clients
)
STR
: Simultaneous Transmit and Receive (
mandatory for APs
,
optional for Clients
)
NSTR
: Non-Simultaneous Transmit and Receive (
optional for APs and Clients
)
EMLMR
: Enhanced Multi-Link Multi-Radio (
optional for APs and Clients
)
[
320MHz
] Another key differentiator is the 320 MHz channel width support in the 6 GHz band (in 802.11ax or 802.11ac it was 160MHz). While it is unlikely to see 320MHz use in enterprise environments, you will likely see consumer-grade products using this as the default bandwidth. This is also an optional feature in Wi-Fi 7 certification.
[
4096-QAM
] To improve data rates, 802.11be introduced 4096-QAM (4K) modulation, which added two additional MCS indexes (MCS 12 and 13). Please note that MCS 14 and MCS 15 are also available in 802.11be, but these use DCM (Dual Carrier Modulation), which results in lower data rates compared to MCS 12 and 13. Therefore, the highest data rate achievable with 802.11be is MCS 13, depending on the number of spatial streams. For example, MCS 13 with 8 spatial streams (SS) and 320 MHz bandwidth can deliver a maximum data rate of 23 Gbps. 4096-QAM modulation support is an option feature in Wi-Fi 7 certification.
[
max Spatial Stream
] The maximum number of Spatial Stream (SS) support in Wi-Fi 7 is one area where people often get confused. In the early stages of 802.11be development, there was a discussion about supporting 16 spatial streams. However, in the later versions (refer to draft 7.0), this was limited to 8 spatial streams (the same as 802.11ax).
In this context, you may see the maximum data rate of 802.11be specified as 46 Gbps (assuming 16 spatial streams), but this is incorrect
. With 8 spatial streams, you can theoretically achieve a ~23 Gbps data rate on a 320MHz channel in 6GHz, assuming you have a device that supports that many spatial streams (similar to when an AP is acting as a client). When you consider the MLO (client can connect across 3 bands and aggregate throughput across all 3 links and get close to ~36 Gbps data rate). You can refer Francois (@VergesFrancois) mcsindex table to see all those 802.11be data rates.
He may have to remove those data rates listed as
spatial stream values
9 to 16
as it is no longer part of 802.11be
.
[
MRU
] Another important feature of Wi-Fi 7 (or 802.11be) is
MRU
–
M
ulti
R
esource
U
nit allocation for a given station. In Wi-Fi 6, a single RU can be allocated to a given user, and multiple RUs cannot be combined and assigned to one user. However, with the mandatory support for preamble puncturing (a feature introduced in 802.11ax, but not mandated in Wi-Fi 6) in Wi-Fi 7, it becomes possible to use the multi-RU allocations for stations in the cell.
[
512 Block Ack
] Compared to the 256 compressed Block Ack in 802.11ax, 802.11be has expanded it to 512 compressed Block Acks. This enhancement allows Wi-Fi 7 stations to acknowledge a larger block of frames in a single Block Ack frame, improving overall efficiency.
There are some other features like
r-TWT
–
R
estricted
T
arget
W
ake
T
ime,
EPCS
–
E
mergency
P
reparedness
C
ommunication
S
ervices,
SCS
(
S
tream
C
lassification
S
ervice) for Triggered uplink Access come with 802.11be. You can read Eva‘s (CWNE#521) blog post as she was writing about these features recently.
Although not explicitly highlighted as a Wi-Fi 7 feature, every time the Wi-Fi Alliance introduces a new certification program, they aim to enhance Wi-Fi security. The same applies to Wi-Fi 7, where WPA3 is mandated for certification. While WPA3 was required for Wi-Fi 6E in the 6 GHz band, Wi-Fi 7 requires WPA3 support across all three bands (2.4 GHz, 5 GHz, and 6 GHz). Additionally, two new AKM (Authentication and Key Management) types (
AKM#24
: SAE-GDH and
AKM#25
: FT+SAE-GDH) have been introduced. Wi-Fi 7 devices are also required to support Beacon Protection, allowing stations to verify the integrity of beacon frames sent by the AP. Wi-Fi 7 AP always advertises its support for beacon protection in “
Management MIC
” IE in beacon frames. Wi-Fi client stations do not advertise their configuration related to that feature support.
As you can see, Wi-Fi 7 comes with many features, and it will take time to go through each of these important aspects. Since I am currently working on digital content (
Wi-Fi 7 lessons
) for Wi-Fi Training (ETA – mid-February 2025), I will also be publishing a series of blog posts in the coming weeks to help you gain a solid understanding of Wi-Fi 7.