Get Ready for WiFi 7 under the 802.11be Standard

Just as WiFi 6 and 6E are starting to hit the market and new chipsets become available, WiFi 7 is in the works under the 802.11be standard. The new WiFi 7 standard builds on the previous WiFi 6/6E standard under a common trend of iterative improvements: higher total bandwidth, higher data rates, innovative use of modulation formats, and higher user count per device. New technologies like AR/VR, low-latency gaming, data center products, and other real-time streaming applications will rely on WiFi 6/6E and the upcoming WiFi 6 standards. These standards also reduce the reliance on 5G/B5G networks for fast data transfer over shorter distances and they will provide a familiar internet connection via a router.

While this technology still has not hit the market, I would expect more inquiries for experimental systems, evaluation modules, and surface-mountable modules to come up once the first chipsets become available. Now is the time to start thinking about these systems, especially if you’re developing evaluation products to support WiF 7.

Changes from WiFi 6/6E in WiFi 7

The biggest change in WiFi 7 is in the theoretical maximum data rate and bandwidth, continuing with the general trend of expanding WiFi capabilities into higher performance in earlier iterations. In WiFi 7, this is accomplished with higher QAM, higher frequency (into the 6 GHz band), and greater bandwidth allocation.

Many of the system-level design challenges are falling onto chip makers, who are designing highly integrated analog front ends to support new products. Some of the other important changes in WiFi 7 include:

• Forward and backward compatibility: Tri-band operation in WiFi 7 helps ensure backward compatibility, and the preamble structure in WiFi 7 packets is designed to ensure forward compatibility.
• Lower latency target: Reduction in worst-case jitter is written into the standard to support low-latency applications. This is supported with MU-MIMO with more simultaneous spatial streams and greater bandwidth, but lower latency carries a lower EMV limit as shown above.

Just like other wireless designs, simulation and testing at the relevant frequencies is quite important, with the goal of evaluating signal distortion and losses along an interconnect (antenna feedline). Interconnect design and matching networks used in WiFi 5 and WiFi 6 are still relevant in WiFi 6E and WiFi 7 as the frequencies involved have not changed. Existing waveguide designs may need minor adjustment to accommodate the broader bandwidth without attenuation in certain portions of the band, but this type of post-layout simulation can be done with an external field solver utility.

Upcoming Component Trends

To get a glimpse of how upcoming WiFi 7-enabled products will look and feel, we can look at what’s happened with WiFi 6/6E products, specifically with SoCs and modules.

Module Interfaces

If you’re planning to use a module to add WiFi 7 capabilities to your design, you’ll need to consider which interfaces will be used for transferring data to the module on the transceiver. PCIe and USB are the two modules already slated for use in WiFi 6E. For example, the AX210.NGWG.NV Wifi 6E module from Intel has PCIe and USB interfaces available. I would expect to see a PCIe generation as the standard interface for providing high-speed parallel data to a WiFi 7 module. 

SoC Options

If you’re looking to build a more compact, highly-integrated embedded system or mobile device, expect to see SoCs come onto the market soon. This is another trend we’ve seen, where MCUs are being integrated with RF front-ends and other features for use in particular settings, such as networking equipment, IoT, or mobile products. One example is NXP’s upcoming CW641 SoC with integrated WiFi 6E. WiFi 7-enabled systems that require small form factor and high wireless data rates will need an integrated option that can only be found in advanced SoCs.

What PCB Designers Can Do Today

If you want to get a head start on advanced WiFi 7 designs, there are a few points you should learn in order to be successful:

• Start with WiFi 6/6E: In terms of system architecture and frequency of operation, WiFi 7-enabled systems will look a lot like WiFi 6/6E systems. If you can successfully layout a WiFi 6/6E system, then you’re well on your way to success with WiFi 7.
• Learn coplanar waveguide routing: If you look at reference designs and typical RF design guidelines, most will recommend coplanar waveguide routing for the antenna feedline. This is more of an exercise in applying the right clearances and trace widths in your design rules.
• Learn about adaptive beamforming: This is a fancy way for me to tell you to learn how to design wideband phased arrays to support beamforming. This is normally discussed in radar, but beamforming is also used in WiFi 6/6E to ensure high throughput data transmission. For PCB designers working on routers or other WLAN equipment, this will determine how antennas are arranged on the device.

Go Beyond WiFi 7 With WiGig

While WiFi 7 is a big upgrade from previous iterations as it extends WiFi into higher spectrum, offering higher data rates. There is another standard that supercharges data transfer at much higher frequency, known as WiGig. This standard is extends WiFi into the 60 GHz ISM band for short-range, high-throughput data transfer to end user devices. The WiGig standard is better known as IEEE 802.11ad, and it is sometimes called microwave WiFi.

The purpose of WiGig is to offer much higher data rates (reaching into Gbps values), which is something that was normally promised in mmWave implementations of 5G, but without requiring mobile chipsets or modems. The main specifications for WiGig are shown below:

• Operating bands: 2.4 GHz, 5-6 GHz, and 60 GHz
• Data transfer rate: 7 Gbps maximum (maximized with OFDM multiplexing)
• Modulation formats:
  • OFDM: SQPSK, QPSK, 16-QAM, 64-QAM
  • Single carrier: π⁄2-BPSK, π⁄2-QPSK

WiGig uses beamforming to provide data transmission in the 60 GHz band up to 10 m. This is not very much range and is only intended for nearby devices. However, because WiGig compliant products must also operate at the traditional 2.4/5-6 GHz bands, they can still provide connectivity to devices farther from a router or access point.

The next step up from IEEE 802.11ad is 802.11ay, which adds MIMO to WiGig with up to 8 spatial streams. These systems implementing high-frequency beamforming require specialized chipsets, and integrated products from companies like Qorvo are now coming onto the component market. 802.11ay also promises to offer higher range through its use of a phased array as would normally be required in MIMO, which would offer very high resolution and gain when power is directed to a single user up to 300-500 m in range.

Stay On Top of Amendments to 802.11 Standards

The IEEE 802.11 Task Group has a lot going on with development of the various standards. New 802.11 standards are targeting advances in everything from V2X (vehicle-to-everything) networking to sensing systems and optical networking. To support continued development in IoT products and address security challenges, other planned amendments include support for randomized MAC addresses and data privacy standards. You can view the entire list of proposed and tabled changes on the IEEE 802.11 Working Group Project Timelines (effective 11 June, 2021). This set of standards has arguably been one of the most successful, so don’t expect development in this area to slow down.

Whether you’re working with WiFi 7, 5G/B5G/6G, or another advanced wireless system, use the best PCB layout software in Altium Designer® to create your physical design. For more advanced calculations involving S-parameter extraction and EVM simulation, Altium Designer users can use the EDB Exporter extension to import their design into Ansys field solvers. You’ll have everything you need to create and evaluate your design before you begin a prototyping run. When you’ve finished your design, and you want to release files to your manufacturer, the Altium 365™ platform makes it easy to collaborate and share your projects.

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