Tuesday, September 26, 2023

Where Is Wi-Fi Heading?

By Cees Links, GM of Qorvo Wireless Connectivity Business Unit, Formerly Founder & CEO of GreenPeak Technologies

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Something Is Wrong

To understand this, let’s compare it to our road system. We have freeways connecting cities, big through-roads connecting neighborhoods, and the small streets in the neighborhoods. There is a hierarchy. And this hierarchy makes sense. You don’t have freeways in neighborhoods or small streets connecting large cities. But for Internet in our homes, the situation is different.

The Internet, or the cloud, has very high-speed interconnects (100 Gb/s or more), comparable with large freeways. But the exit lane, the pipe to our home called the “local loop” (or the “small cell” in wireless lingo), is usually 100 Mb/s at best, although 1 Gb/s fiber and 10 Gb/s DOCSIS 3.1 are starting to emerge. Then we have the option of a distributed Wi-Fi network in our house or building, for instance 802.11ac at 1 Gb/s or even a wired 10 Gb/s Ethernet cable. And finally, with the connection with the end node (the TV, game station, tablet, smart phone), we’re again at something like 1 Gb/s, although this could even be 7 Gb/s if we use IEEE 802.11d (WiGig).

Something is wrong with this. Where’s the hierarchy? The high speed in the home is not served by the access to the home. We have freeways inside the house, but only a small street provides access to the house. And even inside the house, there is no real hierarchy. Take a look at this visual representation:

Out-of-balance (100 Mb/s – 1 Gb/s – 7 Gb/s)
Out-of-balance (100 Mb/s – 1 Gb/s – 7 Gb/s)

WiGig Doesn’t Help In This Scenario

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It’s no surprise, then, that WiGig (IEEE 802.11ad) hasn’t really taken off yet. Why build a higher multi Gb/s highway in your room, if it connects via a 1 Gb/s pipe to a 100 Mb/s local loop, single lane road? It’s also no

surprise that in this context, the expectations for the tens of Gb/s (IEEE 802.11ay) should not be too high. Higher data rates to the end nodes are great, but if the infrastructure does not support it, then what’s the point?

So, the fact that the step from IEEE 802.11ac to IEEE 802.11ax is a very moderate step in terms of data rate, and a step more focused on higher capacity in the home (multiple users at the same time) makes a lot of sense. But the real hurdle is getting more data to (and from) the home.

Streaming And Bursting Affect Data Rates

To complicate matters further, there are effects to consider from streaming and bursting. There is another factor also, that makes this all even more convoluted. There is a difference between streaming and bursting. To stream a movie, you typically need a lot of continuing bandwidth for quite some time, say a continuous 20 Mb/s for high quality. That sounds quite doable with a 100 Mb/s pipe to your home. However, this 100 Mb/s has a somewhat statistical character. If everyone on the street is watching a movie, then the 100 Mb/s to your house quickly drops to significantly lower rates. Streaming a movie on a Saturday evening can be a challenging experience, as you are not the only one on the street (or in your small cell). It is no different than everyone in the house taking a shower at the same time, causing the pressure of the water system to drop.

Burst is another statistical effect. You can compare it to someone opening all the taps in the home to get as much water flowing as possible. If someone tries to download a movie as fast as possible (to watch it later, for example), it causes a real burst of data consumption as the system tries to get as close as possible to the 100 Mb/s to one house, instantaneously. For a short time, this should be no problem. But of course, it is not sustainable, as the rest of the neighborhood would degrade quickly. From a statistical perspective, the chance that everyone on the street would try to download a movie at the same time is probably not that high, but the fact that bursts have an effect on the available bandwidth is clear.

What Needs To Happen?

With all this in mind, let’s circle back to the problem of the disrupted hierarchy. What needs to be done to restore balance? Because until this problem is solved, it will be very hard to justify advancements on in-home data rates. So, let give this a closer look, because now the usage pattern in the home becomes relevant: how many people are living in the home, how many rooms (floors) does your home have, how many devices are used simultaneously per user, etc.


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