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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 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 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.
Depending on the configuration, Wi-Fi 7 routers and access points will be available in different speed grades, including those offering bandwidths higher or lower than 10Gbps on the 6GHz band.
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.
Going forward, 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, is a way to manipulate 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 have a much higher speed and efficiency 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.
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 6x 160MHz 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) | 1202Mbps (at 160MHz) 600Mbps (at 80Hz) | ≈ 2.9Gbps (at 320MHz) ≈ 1.45 Gbps (at 160MHz) |
| Max Band Bandwidth (theoretical on paper) | 9.6Gbps (8x8) | 46.1Gbps (16x16) |
| Commercial Max Band Bandwidth Per Band (commercially implemented) | 4804Mbps (4x4) | 23Gbps (8x8) |
| Actual Available Max Real-word Negotiated Speeds(*) | 2402Mbps (via a 2x2 160MHz client ) 1201Mbps (via a 2x2 80MHzclient) | ≈ 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) |
(*) The real-world sustained speeds depend on the client and environment and generally are much lower than negotiated speeds. Wi-Fi 6/6E has had only 2x2 clients. Wi-Fi 7 will also use 2x2 clients initially, but it might have 4x4 and even single-stream (1x1) clients.
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, using a fixed channel at a time.
In a nutshell, MLO is Wi-Fi band aggregation. Like Link Aggregation (or bonding) in wired networking, MLO allows combining two Wi-Fi bands, mostly 5GHz and 6GHz, into a single Wi-Fi network (SSID) and connection. The bonded link delivers higher bandwidth and reliability.
MLO only works at its full potential with Wi-Fi 7 clients, and in this case, it can be a game-changer in a wireless mesh network. We can potentially count on having no signal drop or brief disconnection. And it's also when seamless handoff (or roaming) can become truly seamless.
On top of that, on each band, a connection can also intelligently pick the best channel, or channel width, in real time. In other words, it can channel-hop, just like Bluetooth, though likely less frequently.
This new capability will help increase the efficiency of Wi-Fi 7's range, allowing all its bands to deliver faster speed over longer distances than previous standards.
In more ways than one, MLO is the best alternative to the existing so-called "Smart Connect" -- using the same SSID (network name) and password for all the bands of a broadcaster -- which doesn't always work as smartly as expected.
But MLO is not all perfect -- a few things to keep in mind:
- MLO only works with Wi-Fi 7 clients. Older clients, such as Wi-Fi 6 or 6E, will still use a single band at a time when connecting to a MLO SSID.
- MLO requires the WPA3 encryption method and generally won't work with Wi-Fi 5 or older clients.
- The reach of the combined link (of 5GHz and 6GHz) is as far as the range of the shorter band.
By default, the 6GHz band has just about 75% of the range of the 5GHz when the same broadcasting power is applied. That said, MLO can only be truly meaningful with the help of Wi-Fi 7's next feature, Automated Frequency Coordination.
4. Automated Frequency Coordination
Automated Frequency Coordination (AFC) applies only to the 6GHz band, which is the fastest yet the shortest range compared to the 5GHz and 2.4GHz. It's an optional feature -- it's not required for the general function of a Wi-Fi 7 broadcaster.
At any given time, there can be existing applications already using the spectrum. For example, fixed satellite services (FSS) or broadcast companies might have already had called dibs on certain parts of the 6GHz band. A new Wi-Fi broadcaster must not impact those existing services -- a concept similar to DFS channels in Wi-Fi 6 and 5.
That's when AFC comes into play. The idea is that all new 6GHz broadcasters check with a registered database in real time to confirm their operation will not negatively impact other registered members. Once that's established, the broadcaster creates a dynamically exclusive environment in which it can operate without the constraint of regulations like the case of Wi-Fi 6E and older standards.
Specifically, the support for AFC means each Wi-Fi 7 broadcaster can use more power and better flexible antenna designs. How much more? That depends.
But it's estimated that AFC can bring the broadcasting power up to 36 dBm (from the current 30 dBm max) or 4 watts (from 1 wat). It's safe to say AFC will help the 6GHz band to have a comparable range to the 5GHz band -- about 25% more.
Before you get all excited, this feature requires certification, and its availability is expected to vary from one region to another. It won't be available in the US before late 2023, if not after. All hardware released before that is said to be capable of handling AFC, which 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.