A cellular service is a specific capability of smartphones and is typically charged separately from the minutes used for voice. The charge is based on the amount of data transferred to or from the device. This charge can amount to more than the voice charges and includes such things as web browsing, text messaging, download or uploading pictures, and any other activity other than voice service and caller-ID. Cellular capabilities include GPS support and the ability to assist in obtaining a rapid GPS lock. This is called A-GPS (assisted GPS). In the absence of a GPS signal the cell tower's location itself can be used to provide an approximate location.
Cellular networks are generally referred to by a more specific name like 3G network or LTE. It may also be referred to by its implementation like CDMA, GSM/EDGE, or UMTS.
 The G's
Cellular technology progress is measured in G's (generations). Here is a breakdown:
- 1G - analog
- 2G - digital technologies, such as CDMA, GSM, and TDMA, were the first generation of digital cellular.
- 3G technologies, such as EVDO, HSPA, and UMTS, brought speeds from 200kbps to a few megabits per second.
- 4G technologies, such as WiMAX and LTE, were the next incompatible leap forward, and they are now scaling up to hundreds of megabits and even gigabit-level speeds.
- 5G brings three new aspects to the table: greater speed (to move more data), lower latency (to be more responsive), and the ability to connect a lot more devices at once (for sensors and smart devices). You could even turn a router into a cell tower.
- UMTS/HSDPA/HSUPA/HSPA+ - 850, 900, 1900, 2100 MHz
- GSM/EDGE - 850, 900, 1800, 1900 MHz
- CDMA EV-DO Rev A - 800, 1900 MHz, Rev B also 2100 MHz
- LTE - Bands 4,17 or 1,3,5 and perhaps 13, 25 with speeds up to 1.2Gbps
- 5G-NR - All bands, low and high, encoding called OFDM which is similar to LTE