Wi-Fi 7 has a lot to celebrate; its support of both 320 MHz transmissions — double the 160 MHz of Wi-Fi 6 — and 4096-QAM delivers significant speed increases, while the use of automated frequency coordination (AFC) enables higher power operation while mitigating interference from existing 6 GHz incumbents. But according to Gabriel Desjardins, Director of Product Marketing in our Clusterpartner Broadcom’s Wireless Connectivity division, Wi-Fi 7’s “marquee” feature is high-band Multi-Link Operation (MLO).
Wi-Fi 6, explained Desjardins, introduced OFDMA, which is a traffic scheduling technique that results in significant speed gains in both crowded and uncrowded environments. Then, Wi-Fi 6E added a tremendous amount of capacity using the 6 GHz band. However, even with scheduled traffic and more capacity, quality of service limitations remain, particularly around latency.
“There’s a lot more capacity [in 6E], but higher throughput doesn’t help you if you’re still contending with other devices that take up resources in the network. Your latency will [still] be great,” he said, adding that applications growing in popularity like video conferencing and mobile gaming require very low latency, which can be hard to achieve on a crowded home or business network.
“Existing Wi-Fi networks really don’t have a good way to move critical traffic between networks to help you get that quality of service,” he continued. “There is a lot more open spectrum with the introduction of 6 GHz, but there isn’t really an easy way to make use of it to help things like latency. You can slowly switch networks, but that isn’t going to help you when you have applications that need millisecond-level latency.”
Enter MLO, a capability unique to Wi-Fi 7. “The marquee feature of Wi-Fi 7 is Multi-Link Operation,” Desjardins claimed, explaining that this feature allows for “rapid switching between two different Wi-Fi bands.”
This means that if a device connected in the 5 GHz band is suffering from degraded performance due to another device popping up on the network, the MLO function will automatically — and very quickly — switch the first device over to the 6 GHz band.
Broadcom’s mobile client chips make this possible via enhanced multi-link single radio (eMLSR). The chips contain two different radios that monitor both the 5 GHz and 6 GHz bands at the same time, enabling switching that Desjardins said can happen in “tens of microseconds.” On the access point side (AP) of things, Broadcom has enabled simultaneous transmit and receive to allow for simultaneous operation on two channels. “This changes Wi-Fi so that you move to a lower-traffic band anytime you need to,” Desjardins summarized. “MLO vastly improves quality of service, increases throughput and reduces latency.”
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