Sometimes when you are talking on a cell phone, you look around and see a cell tower close by. You may think to yourself, “OK, that’s what I’m using to get a signal,” and that’s the end of it. What you may not realize is that the cellular network is just one of several networks used by your average smartphone. More than one of these may be helping you make that call.
Yes, the most obvious network technology in your phone is the cellular network. Using a SIM (subscriber identity module) card that is unique to you, this network sends and receives voice, text messages and data. Your cell provider charges you for this connection, by the minute, text message or amount of data. Cell networks have a range of several miles.
Most phones can also use WiFi networks, such as those in your house, coffee shop, library, school or business. There are two main differences between the cell and WiFi networks. WiFi doesn’t get billed by the minute or kilobyte, and the range is less than cellular – usually no more than 250 feet. It can be faster than the cell network as well, but not always. Lots of phones will switch seamlessly between WiFi and cellular when accessing data, and some phones can also use WiFi to make regular phone calls, which increases clarity of the voice signal.
A third network in your phone is Bluetooth. This technology wirelessly connects your phone to your car’s audio system, a separate speaker or headphones. Utilizing a shorter range than WiFi or cellular, Bluetooth pairs your phone with other devices (your car, earbuds, even hearing aids). The paired devices then remember each other each time they come into range, such as when you get back in your car. The name Bluetooth comes from a tenth-century Norse king, Harald Bluetooth, who united disparate Danish tribes.
Another network in later model smartphones is NFC, Near Field Communication. This has the shortest range of all four technologies we’ve talked about, about an inch-and-a-half. When you hold your smartphone up to a “contactless terminal” (AKA ApplePay, Google Wallet) and authenticate yourself (fingerprint, facial recognition, passcode), NFC connects to the store’s payment network, and charges your credit or debit card.
There are built-in apps that leverage one or more of these networks. For example, the WiFi and cell networks can be used in locations to broadcast alerts about weather, missing children, etc. More nefariously, stores with “free WiFi” can broadcast messages as you stroll the aisles, alerting you to specials and sales.
Although you would think your location (using the Global Positioning System) would be a fifth network, GPS actually uses a combination of cellular and WiFi signals to hone in on your location. If you have disabled WiFi, you may have seen a message that turning it back on will increase the accuracy of GPS.
And even though the new cellular technology coming down the pike is called 5G (for Fifth Generation), it won’t actually be a fifth network, only replacing the current cell technology.