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
Something I can answer! I work in a related field. Hopefully this doesn’t get buried.
The receive signal you see on your phone is how good the signal is from the “control channel.” The control channel directs traffic and give you a voice channel assignment when you’re trying to make a phone call. All those bars tell you is how good the receive sensitivity is of the site that your phone is registered to. So that’s what that means.
Think of the control channel as a data cable between your computer and your router, but instead that data cable is a radio frequency. The frequency is dependent on the carrier, but that’s how you maintain a data connection between your phone and the site.
So your phone maintains a connection to that site via an radio frequency. Part one done. The control channel broadcasts and your phone listens to that control channel for information.
Step two: making a call.
When you dial your BFF’s phone number a few things are happening. When you push that button to make the call, you’re sending an information packet to the control channel saying “hey I want to make this phone call.” The control channel acknowledges your request and looks for a voice channel for you. There’s a varying number of voice channels available at a site depending on how many users need access.
The control channel goes through and finds you a voice channel and sends that back to your phone. The call is set up and a bunch of background network stuff happens to deliver the voice from point A to point B.
Step three: call ends.
On the cellular network, when you hang up, that voice channel you were using becomes available for the next call. So on and so forth. Now this is happening with hundreds of devices at any given time. Most cellular can manage voice and data on the same channels. Using the control channel, your data and voice is all being managed by that control channel and it’s also delivering information to your phone. The control channel tells your phone “hey guy/gal call incoming on channel X/text is in inbound” and vice verse.
So why do they get congested in stadiums? Because there’s 10’s of thousands of people trying to send data and/or voice calls and the cellular network is doing its best to keep up. When your text hangs it’s because it’s cueing your text. Someone was there before you. You’re essentially waiting in line. Voice is different. You just won’t get a channel and won’t be able to make a call. You typically won’t get any indication this is occurring. But I assure you it’s trying it’s best.
Sidenote: This is why cellular networks are terrible in high call volume situations. Especially emergencies.
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