A cellular network is a radio network divided into cells with base stations. Each cell has a base station that serves mobile devices in its area. Cells overlap so that calls can hand off without dropping. The same frequencies are reused in different cells, which allows millions of users on limited spectrum.

The concept was developed at Bell Labs in the 1940s and 1970s. The first commercial cellular network launched in Japan in 1979. Nordic countries followed in 1981. The U.S. launched in 1983. Each generation brought faster data: 1G analog voice, 2G digital voice, 3G mobile data, 4G broadband, 5G high speed and low latency.

Generations of cellular

• 1G: analog voice, 1980s
• 2G: digital voice and SMS, 1990s
• 3G: mobile internet, 2000s
• 4G LTE: broadband data, 2010s
• 5G: high speed, low latency, 2020s

Cellular networks cover most of the populated world. They connect billions of phones. They also connect cars, sensors, and machines. The network is not just for calls anymore. It is the infrastructure of mobile life.