Mobile generations and protocols

Mobile telecommunication has passed through five generations:

• 1G (around 1982): analog voice calls.
• 2G (1991): digital voice, plus text messages (SMS) and picture messages (MMS).
• 3G (2001): voice and data, so phones could use the Internet.
• 4G: fast broadband, for multimedia and video.
• 5G: speeds in gigabits per second, built for the Internet of Things (IoT) and machine-to-machine (M2M) communication.

A protocol is a set of rules for communication. Protocols handle flow control (not sending faster than the receiver can take), access control (who may use the channel when), and addressing. Important ones:

• HTTP (HyperText Transfer Protocol): the rules of the web. A browser sends a request, and the server sends back a response. It runs over TCP.
• FTP (File Transfer Protocol): for transferring files between computers, on a client-server basis.
• PPP (Point-to-Point Protocol): for a direct link between two devices, such as two routers, or a home computer and its Internet service provider.
• SMTP (Simple Mail Transfer Protocol): for sending email, using the information in the message header.
• TCP/IP: the basic protocols of the Internet. IP gives each node an address and routes packets to it; TCP breaks the data into packets, makes sure they all arrive, and puts them back in the right order.