When you travel to a remote area with no cellular coverage, you might wonder whether you can use your phone like a walkie-talkie.
Can you call your travel buddies directly without having any cell towers nearby?
Here’s Whether Cell Phones Can Communicate Directly
Cell phones can’t communicate directly with each other using cellular signals and always have to go through a cell tower as they don’t have the required hardware for direct communication. However, phones can communicate directly using Wi-Fi or Bluetooth.
Why Can’t Cell Phones Communicate Directly Using Cellular Signals?
Cell phones can only communicate with a cell tower and can’t directly communicate with each other.
Each phone has a cellular transmitter that uses a predefined set of frequency channels to communicate with the nearest cell tower. And the cell tower has cellular receivers capable of receiving data from these channels.
Cell phones also have cellular receivers, but they are not the same as the receivers on cell towers and can’t receive a signal from another phone; they can only read a predefined set of frequency channels transmitted by a cell tower.
Therefore, cell phones can’t directly communicate with each other using cellular signals.
Why Don’t Cell Phones Communicate Directly And Use Cell Towers Instead?
You might wonder why cell phones don’t communicate directly with each other.
There are several reasons to use cell towers instead of direct communication.
To Efficiently Use Available RF Bandwidth
Cell phones use a limited set of radio frequencies, and each carrier only gets a limited number of frequency channels.
If two nearby cell phones use the same frequency channels, the transmission will fail because of interference. So if cell phones use direct communication, the connection would be unreliable because of interference from nearby phones. There’s no way to eliminate this interference because each phone doesn’t know about the frequencies other phones will use.
On the other hand, a cell tower knows all the phones currently registered in its cell, so it can assign different frequency channels to each phone to eliminate interference.
Moreover, all users registered to a cell tower don’t use the network simultaneously; the number of active users is significantly lower. So a cell tower can use a small set of frequency channels to serve many users.
To Reduce The Size Of Cell Phones
Cellular transmitters on phones only have limited output power (20 mW to 2 W), so the cell tower only receives a weak signal.
However, cell towers have high-gain antennas, powerful amplifiers, and sensitive electronic filters to detect and extract this faint signal.
To directly receive and decode a signal transmitted by another phone, your phone should have a cellular receiver as powerful as the one in a tower. But if we cram all those electronics into a phone, it will become too large and heavy, which is not practical because we want our phones to be as small and light as possible.
What if we increase the transmit power of the phone? But this will also make your phone less portable because of the added electronics; the battery life will also suffer.
Unlike your phone, a cell tower has no size or power limitation and can use a high transmit power to cover the entire area of the cell.
To Increase The Range
Let’s say you want to call someone across the country.
If phones communicated directly, they’d have to use enormous power to transmit the signal.
However, with cell towers, your phone only has to connect to the nearest cell tower: cell towers are connected using long-range links, and you will connect to the receiving phone in no time.
Can You Make Your Phone Communicate Directly With Other Phones?
A cell phone can’t communicate directly with another phone using cellular signals; it always has to go through a cell tower.
However, when two phones are nearby, you can use Wi-Fi or Bluetooth to directly connect them, although this only work for a limited range (typically less than 100m).
You’d need an off-grid communication device, like goTenna Mesh, to call someone across a few kilometers using your cell phone without any cell towers nearby.
Can Walkie-Talkie Apps Communicate Directly With Other Phones?
Walkie-talkie apps can’t make your phone a true walkie-talkie: cell phones don’t have the required hardware for direct communication using cellular signals.
Most walkie-talkie apps use mobile data or Wi-Fi to connect the users. Some apps can also work without a data connection; they can connect two nearby phones directly using Wi-Fi or Bluetooth.
Cell phones can’t communicate directly with each other using cellular signals; they don’t have the required hardware for direct communication and always have to go through a cell tower.
Thanks to cell towers, cell phones can use low-power cellular modems, and network carriers can use their frequency bands efficiently to serve many users.
You can use Wi-Fi or Bluetooth to connect two phones directly, although this only works for a limited range.
Communications Access Technologies