Technology

Wi-Fi 6E isnt here yet—but Broadcom is clearly banking on it

Today, Broadcom announced the availability of a new phone-targeted Wi-Fi chipset, the BCM4389. The new chipset offers support for Wi-Fi 6 and—more interestingly—Wi-Fi 6E.

For those who aren't immediately familiar with the latest bit of alphabet soup, Wi-Fi 6E isn't a new protocol at all. Instead, it's a branding name for 1200MHz of additional spectrum in the 6GHz range. The FCC hasn't yet formally approved the public use of this spectrum, but its chairman Ajit Pai expressed a desire for the agency to "move quickly" in approving it in September. Broadcom's decision to go ahead with designing and releasing actual hardware for use on the spectrum clearly strongly anticipates 6E becoming "a thing" sometime this year.

We're going to spend a little time talking about why Wi-Fi 6E is important before diving into features specific to BCM4389 itself—which go well beyond a simple "connects to 6E if available."

Why Wi-Fi 6E matters

  • This histogram demonstrates the difference between a noisy 5GHz channel and a clean 6GHz channel. Broadcom
  • Please note that these are PHY speeds, not throughput rates—but the difference in throughput should easily scale right along with the PHY. There's no protocol magic needed here, just channels that are double-wide and uncrowded. Broadcom
  • We're a little dubious about how much you need Wi-Fi 6E for "in-vehicle entertainment"—but it would be amazing for AR/VR, where throughput should be high, wires are anathema, and so is latency. Broadcom

Frankly, the jury is still out on how great Wi-Fi 6 really is. Although the Broadcom VP we spoke to confidently stated that "OFDMA is working quite well on Broadcom chipsets, and the 4389 is no exception," the vendor-unaffiliated RF engineers we've spoken to paint a different story. Even if Broadcom's designs have 100% solid OFDMA, the majority of access points, phones, and laptops absolutely do not, as verified exhaustively by Tim Higgins at Smallnetbuilder.

Without OFDMA, Wi-Fi 6 is a bit of a pig in a poke. The protocol offers other features that aren't in question—such as higher bitrate 1024QAM encoding for devices with very good connections—but OFDMA is the really killer feature that was supposed to make Wi-Fi 6 perform so much better and more consistently in crowded environments.

Wi-Fi 6E is in a much better position to show obvious, immediate, seat-of-the-pants improvements when it becomes available. Due to its use of 1200MHz of contiguous, uncongested 6GHz spectrum, it can offer seven non-overlapping 160MHz channels, as compared to 5GHz's two-or-three-if-you're-lucky 80MHz channels. This means much easier channel planning for enterprises and much less likelihood of being unavoidably congested by neighboring networks if you're an urban apartment dweller.

In addition, the 160MHz channels really do mean double the available throughput—and the lack of legacy devices in the spectrum means no ancient, slow devices hogging up all the airtime. The slightly lower range and decreased throughput of 6GHz as compared to 5GHz—which Broadcom characterized as "roughly 10%-20% less range"—should also be viewed as a feature, not a bug.

Remember, decreased range and penetration doesn't just mean "my router doesn't reach as far"—it also means "my neighbors' networks don't mess with my network as much." We are hopeful that widespread 6E adoption will ultimately mean the death of the enormously expensive standalone router and the final move to Wi-Fi mesh (or mesh-capable) APs for everyone.

For those of you trying to figure out in advance what the slightly decreased range and penetration means for you, we'll have considerably more detailed recommendations soon in a feature dedicated to access point placement. (One really short rule of thumb—which hasn't exactly changed from 5GHz, we just mean it extra serious now—is to plan for no more than two walls in between access point and station.)

Why the BCM4389 matters

  • BCM4375 is the chipset powering the Samsung Galaxy S10's Wi-Fi, for reference. Broadcom
  • We'd recommend taking the actual numbers here with a grain of salt—but "faster, lower latency, lower power, faster pairing, better BT headphone experience" should be a reasonable take, based on the technology improvements. Broadcom
  • Broadcom's process shrink from 28nm to 16nm is good for a power consumption improvement by itself. The addition of a low-power radio for background scans and wake-up calls is even better. Broadcom
  • "MIMO BT" is a branding thing, not a technical spec, and it's a little misleading. What it really refers to is beam-forming TX and MRC RX in the chipset's radio. Broadcom

As always, we caution readers to take vendor claims that haven't been third-party verified yet with a grain of salt. But the technological improvements in the BCM4389 certainly look compelling.

Lower power consumption

A recent Broadcom chipset, the BCM4375, powers the Wi-Fi in Samsung's S10 line of flagship phones. Although our own Ron Amadeo did not love the S10+ he tested, and neither of us is fond of Samsung's software, I haven't heard anRead More – Source

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