When inside a large group of people (at a stadium, concert, festival), why does your phones internet data stop working despite having full bars? Why does such a large presence of phones in one area limit every phones’ usability and ability to even simply send a text message?
In: Technology
Cell phones are just fancy radios. When it comes down to it, just like only one thing can be broadcast to your car radio on each “channel”, cell phone radios have the same limitations, but with a lot of fancy work to let them manage and share the same space without getting in each other’s way.
Imagine a room where a few people upfront are answering questions and have megaphones, and when you want to ask a question you ring a quick bell that doesn’t interfere (too badly) with the people currently talking, but just letting them know to get to you when they are next available. Now, if there are way to many people trying to do that at the same time? The people at the front just get a chorus of bells ringing constantly and can’t hear the questioners and so the “system” grinds to a halt. You can still hear the megaphones just fine (you have good signal strength) but they can’t get any connections completed because then questioners can’t be heard over all of the people indicating they want a connection when’d one becomes available.
The solution to this is to break people down into different rooms so that they don’t interfere with each other. As more and more people use cell phones, companies have been making each station smaller, so that those same bands (or channels) can be reused by someone else farther away. Radio stations do this too, but need hundreds of miles separating the channels, which is why each city has different channels in use to not interfere with neighboring ones.
But once you get down to a very very small area like a stadium, the signals from one side can still reach most other users in the stadium, so you can’t reuse frequencies once you get down to that smallest area and everyone has to share the exact same spectrum. Everyone is stuck in the same room together that wasn’t designed to take that many questions all at once and adding more speakers or bigger megaphones doesn’t help at all.
One of the main advantages of the next generation of cell service, 5g, is that it *doesn’t* carry far at all, and will help break those minimum sized crowded rooms up into smaller ones because you can use frequencies that don’t get interference or connections from even 200 ft away, and so you can put a ton of stations out that only talk to the people in each section of the stadium, kind of similar to how Wi-Fi can handle very dense populations at conventions by having tons and tons of shorter range devices each serving a small chunk of the total.
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