Wireless networks as we know them today is celebrating it’s 20th birthday this year. Happy Birthday Wi-Fi!
Wi-Fi has come a long way from 802.11 Prime with 1mbps and 2mbps data rates supporting STAs such as Personal Device Assistants and external PCI cards for laptops. Now Wi-Fi is common place, in fact not having is highly unusual and even car manufacturers are beginning to install wireless connectivity in vehicle so that end users have continuous connectivity from home, to school, to work to the coffee shop.
And in the time between 802.11 Prime in 1997 to now looking at 802.11ac wave 2 the number one goal has been speed. More speed. More speed to support high bandwidth applications such as YouTube and Netflix. More speed to support latency sensitive devices such as VoIP phones. Speed so you don’t have to wait even 2 seconds to receive an email, or wait for a webpage to load. Speed is tangible. Speed is sexy. Speed sells devices.
It would seem though, that the Wi-Fi community is at an impasse. How much more speed can we really suck out of our given RF medium? And will the end user even notice if we change their modulation scheme from 256 QAM to 1024 QAM with the introduction of 802.11ax? Or if we change from MIMO to MU-MIMO?
I think the answer to this question is… it depends.
I think for the average end user they’ll not notice a difference if their smart phone supports MU-MIMO or if it has 3 or 4 spatial streams. Except that, they may notice some significant challenges with the battery life of their device. I think that the implementation of the latest Wi-Fi technologies are at the mercy of battery technology. Until batteries can support more spatial streams and MU-MIMO while also being able to fit into smaller and smaller form factors, end users will stop paying attention to how fast their Wi-Fi is.
I think where the importance of newer Wi-Fi technologies lies is in the ability to plan for capacity. This is especially true in schools. The education environment is perhaps the only Wi-Fi critical environment where every user on an AP could be downloading or streaming the same content at the same time. Therefore some of the less common Wi-Fi technologies are going to become really critical for classroom environments where speed is related to capacity.
MU-MIMO is one of the technologies in 802.11ac Wave 2 that could be potentially very useful in a classroom environment. It’s most useful when devices are equally separated around an AP, all or most devices are homogeneously supporting MU-MIMO (in a district provided 1:1 this would be presumed), and all of the devices are trying to receive roughly an equal amount of data. This sounds like an ideal technology for a classroom where students would be working on roughly the same assignment at the same time where they are required to be on a particular website or book, or looking at a particular video.
The problem with the usefulness of this is that most device manufacturers are not going to spend the extra money on a chipset that supports MU-MIMO, or extra money trying to develop a battery that will support it because it is a unique and relatively small market problem to solve.
So is it worth it to keep investing in newer Wi-Fi technologies if device manufacturers are always going to take the cheapest route that covers the majority of the marketshare? I think so. I think it’s worth it to keep pushing the boundaries, but I also think it’s time that the Wi-Fi Communities governing bodies start working to establish not just standards for the PHY but standards for the devices as well.
End users will always have a better experience when device manufacturers and technology innovators are working hand in hand.