Issue link: https://resources.mouser.com/i/1313794
5 Qorvo 2020 When two devices are talking through each other over the same channel simultaneously, it means that the messages are getting garbled and both need to be sent again. It's no surprise, then, that the throughput in dense environments can collapse in continuous retransmissions. Again, this is a form of interference. This interference is made worse by the fact that routers and access points have attempted to improve range via the highest output power possible. Anyone who has ever been to a crowded party can understand this scenario. The more everyone speaks louder to be heard, the more the overall noise goes up and any real opportunity to communicate goes down. More output power just causes more interference. Even worse, higher output power in some channels of the band causes the signal to "bleed" into the neighboring channels—another form of interference— causing the capacity of the band and the total Wi-Fi system to degrade. So, what to do? Distributed Wi-Fi This is where Wi-Fi 6 (.11ax) comes into play. The goal of this new standard is less about higher data rates, and more about the use of as many channels in the 2.4GHz band or the 5GHz band as possible—at the same moment in the same space (for instance, in the same house). Let's look at an example of why this is needed. Imagine a family living in a house with multiple rooms, running different applications at the same time. In the past, this meant that everyone was using the same channel to communicate with the central router in the closet, but with all the interference limitations discussed above. The scenario that Wi-Fi 6 enables is that every room in the house has a small access point (the size of a deck of cards) running on a different Wi-Fi channel, and those access points are wirelessly connected over Wi-Fi to the central router in the closet. Now the applications are on different channels and not interfering with each other. This is a true Wi-Fi "system," and the name of the game now is total capacity—using multiple channels at the same time without interfering with each other, thereby optimizing total indoor throughput. So, the goal of Wi-Fi 6 is full coverage of a home (or a building), and maximum performance in every room, which results in maximum overall capacity for everyone (at the system level). Smartphones, computers, tablets, and routers communicating with each other on the same channel sometimes "talk through each other." Not surprisingly, this jumbles the communication. A sending device usually knows that a packet has not arrived because it does not receive an acknowledgment back from the receiving device within a certain time frame. (We're talking milliseconds here.) The "mechanism" with which devices communicate is called a protocol, which describes how proper communication needs to be handled, including what to do when "talking through each other." A simple part of a protocol is "listen before talking," which What happens if two devices are "talking through each other"? means that before a device starts to send a data packet, it listens to ensure that nobody else is "on the air." But, if two devices both listen, and both conclude that the "air is clear" and start communicating at the same time, it creates a "collision." Some devices can "hear" the interference and will "back off," or stop and wait (again, milliseconds) before sending again. So, typically what happens in dense environments is that more packets collide, and more packets need to be retransmitted with now higher chances of another collision. The consequence is that the performance of the network as a whole can break down. This is what happens, for example, with too many people on a single hotspot.