Eli5:Why is it that cell phones , with their tiny antenaes are able to download files at LTE speeds inside concrete buildings from cell towers kilometers away yet getting wifi to work behind a corner is an exercise in frustration?
In: 2387
For the same reason you can sit in the shade at the park and still be able to read a book by sunlight but if you were trying to read in a cave with a lantern you would need it right next to you rather than around the nearest corner.
One of those sources is MASSIVELY more powerful despite being quite a bit further away
Simplified version: you can either have *faster* speeds or a *farther* connection. You sacrifice one for the other.
As you’ve noticed yourself, with cellular you get much farther distance but at the cost of speed.
3 main reasons:
1) you are comparing a use case (wifi) with two small devices with relatively bad antennas transmitting in all directions at low power with another case (4G) where on one side you still have the bad device, but on the other side you have a very effective antenna, transmitting just over a narrow angle and at a power orders of magnitude higher. Obviously the second case works better.
2) 4G frequency is usually lower than the WiFi frequency. And the lower the frequency, the better it travels through stuff. The drawback is that the lower it is, the less data you can transmit (yes, I know, that sentence is almost wrong, it has a lot of shortcuts).
3) 4G frequencies are used by a handful of actors with properly dedicated frequencies so it is usually a fairly clean environment. On the other hand, the WiFi frequency is basically a free for all with anyone being able to transmit over it (under specific conditions of course). This means you would have a lot more devices trying to talk over each other. Your phone is talking to your router but your neighbours phone talking to their router is also using the same frequency and everyone have to share it. There are WiFi mechanisms for this but if it gets too crowdy, then it impacts the speed.
The answer is they don’t. Commercial concrete buildings usually have multiple “micro cell” sites installed throughout the building to support cell phone data and voice communication. If this wasn’t done the density of cellphones would quickly overwhelm most cell phone towers in cities.
Cell phone towers have limits to the number of simultaneous connections. 5G requires even shorter distances than LTE, so there has been a major increase in the number of cell towers from previous needs. Here’s some good apps and websites to see just how many are around you. You won’t believe how many are located at Sport Stadiums
https://www.waveform.com/blogs/main/cell-tower-mapping
Most hotspots have a damn weak broadcast power! So the further you are, the nore likely your data transfer speeds are equaling those of the 1990’s.
Cell phone towers are large massive towers that are built to provide cellular signal to large areas of the city. They have miles in range and use a lot of power.
Your wifi router plugs into the wall and is made to NOT be so powerful as to extend into other buildings and cause interference with other wifi routers. Their range is 200-300 feet when there is no walls between the router and the device using it.
So by design they have different ranges because by design they serve different purposes.
There are many good explanations of different factors at play here (frequencies, number of routers/cell towers, signal power, etc), but I’d like to clear up a couple of assumptions you made here. In urban areas, cell towers are generally not kilometers away. And when cell towers *are* kilometers away, you won’t get your typical LTE speeds, it will be slower. There is always a tradeoff between connection speed and signal range – the higher the signal range, the lower the speed, and vice-versa. Of course, every new generation generally increases the speed for a certain range, but that truth still stays. I mean, think about it, if you didn’t have that tradeoff, we would all (probably) be using satellite internet.
Also, Concrete buildings don’t necessarily let cell signals through. What most concrete buildings have, though, are windows – and they do let signals through. But if you’re in a concrete building without any windows, and there’s nothing to bring the cell signal there, chances are, you won’t get any reception.
Cell towers are absolutely BLASTING their signal–they have permission from the FCC do to this, and it works. WiFi is meant to be a personal or smaller-scale thing, and works at far lower power levels. As a result, the signals are easier to block.
If you want a fun read, google “cantenna” for a cool way to boost your signal.
I wasn’t satisfied with the other answers. This is my best Eli5. *Source: used to work at AT&T.*
– Your phone usually hums a low tone (under 1ghz) which can penetrate most walls with ease and reach a cell tower that’s listening miles away. Your phone has to compete with all of the other phones and cell towers talking within miles of you, but luckily every phone and tower abides by strict rules and has a ton of space to adjust their pitch so they know who is talking.
– On the other hand, with Wi-Fi and Bluetooth, your phone has to use a shrill voice which barely reaches the other room to talk to your router (2.4ghz or 5ghz). As it happens, everything else in your house is forced to talk at only those 2 high pitches and it’s really hard for everyone to hear each other. Kind of like a school cafeteria at lunchtime. Even your microwave, when running, has to use this same shrill pitch.
T-Mobile service used to really suck in comparison to Verizon and AT&T because it was only licensed to talk in a relatively high pitched voice. Luckily, the government let them start humming that low, penetrating frequency like the other carriers, in exchange for a bag of money, of course.
You fucking serious? You don’t know how cell phones and wi fi works?. Wifi is a limited signal coming from a small router. Not very powerful. A cell phone works off a giant tower.
How do you not know how the thing you carry in your pocket everyday works?
Latest Answers