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Broadcom today announced its next step in Wi-Fi 7 optimization, the FBAR integrated front-end module (FiFEM) devices for all Wi-Fi access point (AP) applications.
These new devices can be added to the company's existing Wi-Fi 7 chips to better the performance of standalone access points, routers, or residential gateways.
Front-end module: Conventional FEM vs. Broadcom’s new FiFEM
Each Wi-Fi broadcaster needs a FEM, an essential accompanying RF module that consists of acoustic filters, amplifiers, and other parts. The FEM decides how signal broadcasting of each radio band takes place and plays an important role in other characteristics of a broadcaster.
FEM and Wi-Fi 7
Like all internal parts of a radio broadcaster, FEMs are generally delicate and easily susceptible to environmental elements, such as sound waves. That's especially true with the 6GHz frequency band, available in Wi-Fi 6E and Wi-Fi 7.
Additionally, Wi-Fi 7 has many new features that put even more stress on the FEM. Two examples:
- Multi-Link Operation (MLO) combines multiple bands into a single link, making the coexistence of 5GHz and 6GHz signals a critical part of Wi-Fi hardware.
- The automated Frequency Coordination (AF) feature means the radio frequency (RF) broadcasting power can reach up to 10 Watts per band (instead of the current 1 Wat ceiling). Consequently, FEM optimization will play an even more important part in Wi-Fi 7 broadcasters.
New to Wi-Fi 7? The cabinet below will fill you in.
Wi-Fi 7 in brief
Wi-Fi 7 has four major improvements over existing standards.
1. The all-new 320MHz channel width
The first thing to note about Wi-Fi 7 is the new and much wider channel width, up to 320MHz, or double that of Wi-Fi 6/6E.
This new channel width is generally available on the 6GHz band, with up to three 320MHz channels. However, Wi-Fi 7 can also combine portions of the 6GHz and 5GHz bands to create this new bandwidth—more in the Multi-Link Operation section below.
Details of Wi-Fi channels can be found here, but the new channel width generally means Wi-Fi 7 can double the base speed, from 1.2Gbps per stream (160MHz) to 2.4Gbps per stream (320MHz).
So, in theory, just from the width alone, a 4x4 broadcaster 6GHz Wi-Fi 7 can have up to 9.6 Gbps of bandwidth—or 10Gbps when rounded up. But there's more to Wi-Fi 7's bandwidth below.
Wi-Fi 7 also supports double the partial streams, up to 16. As a result, technically, a 16-stream (16x16) Wi-Fi 7 6GHz band can deliver up to over 40Gbps of bandwidth, especially when considering the new QAM support below.
Like Wi-Fi 6 and 6E, initially, Wi-Fi 7 will be available as dual-stream (2x2) and quad-stream (4x4) broadcasters and dual-stream clients. In the future, the standard might have 8x8 broadcasters and single-stream or quad-stream clients.
Again, you need a compatible client to use the new 320MHz channel width. Existing clients will connect using 160MHz at best. In reality, the 160MHz will likely be the realistic sweet-spot bandwidth of Wi-Fi 7, just like the 80MHz in the case of Wi-Fi 6.
2. The 4K-QAM
QAM, short for quadrature amplitude modulation, manipulates the radio wave to pack more information in the Hertz.
Wi-Fi 6 supports 1024-QAM, which itself is already impressive. However, Wi-Fi 7 will have four times that, or 4096-QAM. Greater QAM means better performance for the same channel width.
As a result, Wi-Fi 7 will be much faster and more efficient than previous standards when working with supported clients.
Wi-F 7 vs. Wi-Fi 6/6E: The realistic real-world speeds
With the support for the wider channel width and higher QAM, Wi-Fi 7 is set to be much faster than previous standards on paper.
You might have read somewhere that Wi-Fi 7 is "up to 4.8 times faster than Wi-Fi 6," and hardware vendors will continue to combine the theoretical bandwidth of a broadcaster's all bands into a single colossal number—such as BE19000, BE22000, or BE33000—which is excellent for advertising.
Like always, these numbers don't mean much, and things are not that simple. In reality, a Wi-Fi connection generally happens on a single band at a time—that's always true for Wi-Fi 6E and older clients—and is also limited by the client's specs.
The table below summarizes what you can expect from Wi-Fi 7's real-world organic performance compared to Wi-Fi 6E when working on the 6GHz.
| Wi-Fi 6E | Wi-Fi 7 | |
| Max Channel Bandwidth (theoretical/top-tier equipment) | 160MHz | 320MHz |
| Channel Bandwidth (widely implemented) | 80MHz | 160MHz |
| Number of Available Channels | 7x 160MHz, or 14x 80MHz channels | 3x 320MHz, or 7x 160MHz channels, or 14x 80MHz channels |
| Highest Modulation | 1024-QAM | 4096-QAM |
| Max Number of Spatial Streams (theoretical on paper / commercially implemented) | 8 / 4 | 16 / 8 (estimate) |
| Max Bandwidth Per Stream (theoretical) | 1.2Gbps (at 160MHz) 600Mbps (at 80MHz) | ≈ 2.9Gbps (at 320MHz) ≈ 1.45Gbps (at 160MHz) |
| Max Band Bandwidth (theoretical on paper) | 9.6Gbps (8x8) | 46.1Gbps (16x16) |
| Commercial Max Band Bandwidth Per Band (commercially implemented) | 4.8Gbps (4x4) | 23Gbps (8x8), or 11.5Gbps (4x4) |
| Available Max Real-word Negotiated Speeds(*) | 2.4Gbps (via a 2x2 160MHz client) 1.2Gbps (via a 2x2 80MHz client) | ≈ 11.5Gbps (via a 4x4 320MHz client) ≈ 5.8Gbps (via a 2x2 320MHz client or a 4x4 160MHz client) ≈ 2.9Gbps (via a single stream 320MHz client or a 2x2 160MHz client) ≈ 1.45Gbps (via a single stream 160MHz client or a 2x2 80MHz client) |
| Available Clients (example) | 2x2 (Intel AX210) | 2x2 (Intel BE200 / Qualcomm NCM865) |
(*) The actual negotiated speed depends on the client, Wi-Fi 7 specs, and environment. Real-world sustained rates are generally much lower than negotiated speeds—capping at about two-thirds at best. Wi-Fi 6/6E has had only 2x2 clients. Wi-Fi 7 will also use 2x2 clients primarily, but it might have 4x4 and even single-stream (1x1) clients.
Like Wi-Fi 6 and 6E, Wi-Fi 7 has been available only in 2x2 specs on the client side. That, plus the sweet-spot 160MHz channel width, means, generally, it's safe to conservatively expect real-world rates of the mainstream Wi-Fi 7 (160MHz) to be about 20% faster than top-tier Wi-Fi 6E (160MHz) counterparts.
However, the new standard does have more bandwidth on the broadcasting side. So, it can handle more 2x2 clients simultaneously with high-speed real-world rates. And that's always a good thing.
3. Multi-Link Operation
Multi-Link Operation, or MLO, is the most exciting and promising feature of Wi-Fi 7 that changes the norm of Wi-Fi: Up to Wi-Fi 6E, a Wi-Fi connection between two direct devices occurs in a single band at a time. MLO changes that.
It's worth noting that MLO is a feature and not the base of the standard, meaning it can be supported by a particular device or not.
In a nutshell, MLO is Wi-Fi band aggregation. Like Link Aggregation (or bonding) in wired networking, it allows combining two or more Wi-Fi bands into a single Wi-Fi link (single SSID). That said, you can have MLO as long as the broadcaster has more than one band, which is the case with all Wi-Fi 7 hardware.
Still, generally, there are two MLO operation modes:
- STR-MLMR MLO (Simultaneous Transmit and Receive Multi-Link Multi-Radio): It's multi-link aggregation using all available bands (2.4GHz, 5GHz, and 6GHz) to deliver higher throughput, lower latency, and better reliability. (For dual-band hardware, such as the Asus RT-BE88U, this mode combines the 2.4GHz and 5GHz band.)
- E-MLSR MLO (Enhanced Multi-Link Single Radio): It's multi-link using dynamic band switching between 5GHz and 6GHz—this mode is only available to broadcasters with these two bands—to deliver load balancing and lower latency.
No matter which mode is used, the gist is that the bonded link delivers "better" connection quality and "more" bandwidth.
It's important to note, though, that at the end of the day, MLO increases the bandwidth, allowing different applications on a client to use the two bands simultaneously. The point here is that no application on the client can have a connection speed faster than the fastest band involved. A speedtest application, for example, still uses one of the bands at a time. This connection speed is still limited by the hardware specs on both ends of the link, whichever is lower.
So, the MLO feature affords supported clients the best probability of connecting successfully at the highest possible speed using the fastest band at any given time, which changes depending on the distance between the client and the broadcaster.
Considering the vast amount of pre-Wi-Fi 7 clients on the market, keep the following in mind about MLO in consumer-grade hardware:
- By nature, link bonding will be more complicated than single-band connectivity—there are just too many variables.
- MLO only works with supported Wi-Fi 7 clients. Some Wi-Fi 7 clients might not support it. (A Windows computer must run Windows 11 24H2 or later to support MLO.) Considering the different performance grades and hardware variants, the result of MLO will vary case by case.
- Wi-Fi 6 and 6E and older clients will still use a single band at a time when connecting to a MLO SSID. And they might pick whichever of those is available in the bonded link. You might get frustrated when they use the slow band instead of a faster one, like in the case of Smart Connect. That happens.
- An MLO SSID requires the WPA2/WPA3 or WPA3 encryption method and won't allow legacy clients to connect. This can be a big headache for those assuming the SSID will just work with all clients. In other words, turning MLO on can cause a big compatibility issue with the hardware's primary SSID(s).
- The reach of the bonded wireless link is as far as the range of the shorter band.
MLO in real-world usage: Great for wireless mesh, but client compatibility can be a big issue
In so-far real-world experience, MLO has proven to be a game-changer in a wireless mesh network by fortifying the Wi-Fi link between broadcasters—the backhaul—both in terms of speed and reliability.
Wi-Fi 7 mesh systems, via my testing method, have shown sustained wireless backhauling links over 5Gbps at 40 feet away.
In terms of range, the bonded link has the reach of the shortest band involved. Since the 6GHz band has just about 75% of the range of the 5GHz when the same broadcasting power is applied, MLO can only be truly meaningful with the help of Wi-Fi 7's fifth and optional feature, Automated Frequency Coordination, mentioned below.
On the other hand, for devices (clients), the effect of MLO has proven to trade the (lack of) backward compatibility for a relatively subdued impact on performance.
Specifically, with single broadcasters or mesh systems with wired backhauling, the feature plays an insignificant role and generally does not noticeably improve the real-world rates of individual clients—currently available at 2x2 specs, such as the Intel BE200 or Qualcomm NCM865 chips—despite the higher negotiated speed of the bonded link.
In a way, MOL is the alternative to the finicky "Smart Connect", where a single SSID is used for all of the broadcaster's bands. In fact, you can think of MLO as the enhanced version of Smart Connect with higher bandwidth and security requirements.
Some hardware vendors, such as Linksys or Asus, require Smart Connect for their broadcaster's primary SSID before MLO can be turned on. In this case, you have to choose between the following in terms of SSIDs:
- Having a primary SSID (via Smart Connect), which is MLO-compliant in terms of security, and an optional 2nd virtual MLO-enabled SSID. This SSID likely won't work with many legacy clients, and users will need to use the hardware's virtual or Guest SSIDs (if available)—Asus has plenty of them via its SDN feature—with lower security requirements to support legacy clients. Or
- Turning off Smart Connect to manage the band individually and without MLO.
Other vendors, such as TP-Link, always use MLO as a secondary virtual SSID, which is the way they handle Guest or IoT SSIDs. This approach saves the users from the MLO trap—they won't be prompted to turn it on by default—but the compatibility with the MLO-enabled SSD remains.
That said, MLO is best used when you have mostly Wi-Fi 6E and newer clients, which won't be the case until years from now. In the meantime, this feature should be turned off when you use a single Wi-Fi 7 broadcaster or a mesh with wired backhauling unless you have the option to create additional SSIDs with lower security requirements for existing clients.
4. Flexible Channel Utilization (FCU) and Multi-RU
Flexible Channel Utilization (FCU) (a.k.a. Preamble Puncturing) and Multi-RU are two other items that help increase Wi-Fi 7's efficiency. With FCU, Wi-Fi 7 handles interference more gracefully by slicing off the portion of a channel with interference, 20MHz at a time, and keeping the clean part usable.
In contrast, in Wi-Fi 6/6E, when there's interference, an entire channel can be taken out of commission. FCU is the behind-the-scenes technology that increases Wi-Fi's efficiency, similar to the case of MU-MIMO and OFDMA.
Similarly, with Wi-Fi 6/6E, each device can only send or receive frames on an assigned resource unit (RU), which significantly limits the flexibility of the spectrum resource scheduling. Wi-Fi 7 allows multiple RUs to be given to a single device and can combine RUs for increased transmission efficiency.
5. Automated Frequency Coordination
Automated Frequency Coordination (AFC) is an optional feature and deals with the 6GHz band, so it's not Wi-Fi 7-exclusive—the band was first used with Wi-Fi 6E. It's not required for a Wi-Fi 7 broadcaster's general function. In fact, it wasn't even mentioned in the initial certification by the Wi-Fi Alliance.
Due to local regulations, the 6GHz band's availability, hence, the implementation of the AFC feature, differs around the world. For this reason, some Wi-Fi 7 broadcasters, such as the Asus RT-BE88U or the TP-Link Archer BE230, forgo this band to remain dual-band.
Still, Wi-Fi 7 makes AFC more relevant than ever. That's because the 6GHz band has the highest bandwidth (fastest) yet the shortest range compared to the 5GHz and 2.4GHz bands when using the maximum allowed broadcasting power. Originally, AFC was intended only for outdoor applications, but when implemented, it's significant for all applications.
Here's how AFC would work when/if available:
The feature enables a 6GHz broadcaster to check with a registered database in real-time to confirm that its operation will not negatively impact other existing registered members. Once that's established, the broadcaster creates a dynamically exclusive environment in which its 6GHz band can operate without the constraint of regulations.
Specifically, the support for AFC means each Wi-Fi 7 broadcaster can use more broadcasting power and better flexible antenna designs. How much more? That depends.
However, it's estimated that AFC can increase the broadcasting power to 36 dBm (from the current 30 dBm limit) or 4 watts (from 1 wat). The goal of AFC is to make the range of the 6GHz band comparable to that of the 5GHz band—about 25% more.
When that happens, the MLO feature above will be truly powerful. But even then, Wi-Fi 7's range will remain the same as that of Wi-Fi 6, which is available only on the 5GHz band. Its improvement is that its 6GHz band now has a more extended reach than in Wi-Fi 6E. In other words, AFC allows the 6GHz band to have at least the same range as the 5GHz. And that's significant.
This feature requires certification, and its availability is expected to vary from one region to another. Hardware released before that is said to be capable of handling AFC, which, when applicable, can be turned on via firmware updates.
A crude AFC analogy
Automated Frequency Coordination (AFC) is like checking with the local authorities for permission to close off sections of city streets for a drag race block party.
When approved, the usual traffic and parking laws no longer apply to the area, and the organizers can determine how fast traffic can flow, etc.
To lessen the negative effects of elements on Wi-Fi 7 broadcasters, Broadcom has created a special filter type called Film Bulk Acoustic Resonator (FBAR) to insulate the FEM.
FBAR filters are slated to be better than conventional Surface Acoustic Wave (SAW) filters by, among other things, featuring 0.3 to 0.5 dB less insertion loss and up to 50mA in current consumption.
Broadcom’s FiFEM
To differentiate, Broadcom calls FEM units with integrated FBAR filter "FiFEM", an intimidating-sounding acronym that generally means an improved front-end module.
According to Broadcom, the new FiFEM devices "incorporate best-in-class FBAR filter technology to provide superior 5 GHz and 6 GHz
band coexistence and low in-band insertion loss while significantly reducing the bill of materials (BOM) at the RF front end."
Additionally, they feature "state-of-the-art non-linear power
amplifier (PA) design optimized for Broadcom's Wi-Fi SoC Digital Predistortion (DPD) operation to deliver up to 40% reduction in RF front-end power."
To put things in simple terms, Wi-Fi 7 broadcasters' equipment with the new FiFEM will likely deliver faster-sustained speeds, lower latency, and higher capacities than those that use conventional FEM. That's the idea, anyway.
Here are the highlights of Broadcom's new FiFEM products:
- Integration of 2nd generation Wi-Fi FBAR filter that:
- Provides superior 5-GHz/6-GHz band isolation and efficiency
- Reduces RF BOM and board space
- Avoids yield loss from external filter mismatch
- First non-linear FEM qualified for Broadcom's Wireless FEM Active Management (WiFAM) Gen2 using advanced DPD technology with dynamic bias handling that:
- Enables up to 40% reduction in RF front-end power
- Enhances gateway energy efficiency via average power consumption.
Most importantly, these new FiFEM devices are designed to meet the system specs of existing Wi-Fi 7 chipsets, including the BCM6726 and BCM67263 SoC reference designs first announced in April last year. And they are available in four conventional (3x5 mm) FEM packages, including:
- AFEM-W760-HP1 (6 GHz, +25dBm)
- AFEM-W760-MP1 (6 GHz, +23dBm)
- AFEM-W750-HP1 (5 GHz, +25dBm)
- AFEM-W750-MP1 (5 GHz, +23dBm)
Broadcom says it has begun shipping samples of these FiFEM devices to its early-access customers and partners. Consequently, there will likely be routers and access points with them inside sometime later this year.
The takeaway
Despite existing Wi-Fi 7 broadcasters on the market, the new wireless standard is still under development. It's not yet certified until the end of this year or even earlier next.
These new FiFEMs from Broadcom are one of many reasons it makes sense to get still a Wi-Fi 6 or 6E router that works for your needs today. Wi-Fi 7 only gets better the longer you wait. It won't go anywhere.
As I read this, every time Dong mentions FBAR I kept seeing FUBAR…(Sorry, from my military days). Thanks for the info as always 🙂
That makes two of us :). Thanks for your service, Mike.