GSM

Long ago, people made a new way for phones to talk.

This plan is called GSM. It helped phones work in many lands.

It was first used in a place called Finland.

This made it easy to send text messages. People could also send small bits of data.

Many people around the world used it. It worked in over 200 lands.

Phones connect to small areas called cells. These cells help the signal reach you.

Now, many companies are turning these networks off. But GSM helped change how we talk.

GSM is a set of rules for mobile phone networks.

These rules helped make second-generation, or 2G, digital networks. Before GSM, networks used analog signals. GSM changed this by using digital signals. This made it easier to talk on phones. It also allowed people to send text messages.

GSM began in Europe. Many countries worked together to make it a standard. This meant phones could work in many different lands. It became a global standard. By 2006, over 2 billion people used it.

Phones connect to a cellular network. This network is made of many small areas called cells.

These cells help the signal reach you. Some cells are very large. We call these macro cells. They use tall antennas on masts. Other cells are very small. These are called picocells. They help signals reach people inside buildings. Some cells are even smaller. We call these femtocells. They are used in homes or small offices. Today, many companies are turning off 2G networks. However, the name GSM is still used for many phone technologies.

GSM stands for Global System for Mobile Communications. It is a set of rules for digital cellular networks. These rules are used for second-generation, or 2G, mobile networks.

Before GSM, networks used analog signals to carry calls. GSM changed this by using digital signals instead. This made it much easier for people to talk on mobile phones. It also allowed for new things like text messages.

Today, many people still use the name GSM to talk about mobile technology.

How does this network actually work? It uses a cellular system to send signals. This means the network is divided into many small areas called cells.

There are five different sizes of these cells. Macro cells are very large and use tall antennas on masts. Micro cells are smaller and often used in busy cities. Picocells are tiny and help signals reach inside buildings like airports. Femtocells are even smaller and work in homes or small offices. Umbrella cells cover any gaps between these other areas.

The history of GSM began in Europe. In 1983, a group called CEPT started working on a digital standard. By 1987, fifteen representatives from thirteen European countries signed an agreement. They wanted to create one common system for all of Europe. This helped different countries use the same kind of phone technology. This work was guided by leaders like Armin Silberhorn and Philippe Dupuis. In 1989, the work moved to a group called ETSI.

GSM grew very fast across the whole world. The first GSM network was set up in Finland in December 1991.

Some say the first call was made in July 1991. By 1995, more than 10 million people used GSM. In 1998, that number grew to over 100 million subscribers. By 2006, there were over 2 billion GSM users globally. It was much larger than other competing systems at that time. By the mid-2010s, it held over 90% of the market share.

GSM connects to your phone in many helpful ways. It uses different radio frequencies to send information through the air. Most 2G networks use the 900 MHz or 1800 MHz bands. Some places like the United States use 850 MHz or 1900 MHz.

You might also recognize the small SIM card in your phone. These cards were first launched for GSM in 1996. They help your phone connect to the right network. Even though many 2G networks are shutting down now, GSM changed how we all stay connected.

The Global System for Mobile Communications, or GSM, is a family of standards for second-generation (2G) digital cellular networks. These protocols define how mobile devices, such as phones and broadband modems, communicate with a network. GSM was designed to replace the first-generation (1G) analog networks. It provides a digital, circuit-switched system optimized for full duplex voice telephony. This means two people can talk at the same time. To manage the airwaves, GSM uses time division multiple access (TDMA). This is a method where different users share the same frequency by taking turns in very fast, timed slots.

A GSM network is organized into several distinct parts to keep communication flowing. The first part is the Base Station Subsystem. This includes the base stations and their controllers. The second part is the Network and Switching Subsystem. This is often called the core network because it functions much like a fixed telephone network. There is also an optional GPRS Core Network. This part allows for packet-based Internet connections. Finally, the Operations Support System (OSS) handles the maintenance of the entire network.

To provide coverage, GSM uses a cellular structure. The network is divided into many areas called cells. These cells come in five different sizes to fit different environments. Macro cells use large antennas on tall masts or buildings. Micro cells are smaller and are often used in urban areas. Picocells are very small, covering only a few dozen meters, and are used for indoor coverage in places like airports. Femtocells are the smallest, designed for homes or small businesses using a broadband connection. Umbrella cells are used to fill in gaps or cover shadowed regions between other cells.

The history of GSM began with a push for European unity. In 1983, the CEPT committee began developing a digital standard. By 1987, representatives from 13 European countries signed a memorandum of understanding in Copenhagen. This agreement aimed to deploy a common system across Europe. This effort was guided by officials such as Armin Silberhorn, Stephen Temple, Philippe Dupuis, and Renzo Failli. In 1989, the committee moved to the European Telecommunications Standards Institute (ETSI). Thomas Haug and Philippe Dupuis later received the James Clerk Maxwell medal for their leadership in this development.

GSM saw rapid global growth after its first implementation in Finland in December 1991.

While some believe the first call happened in July 1991, a Nokia engineer named Pekka Lonka claimed he made the first test call earlier that year. By 1995, the number of worldwide subscribers exceeded 10 million. This number grew to 100 million by 1998 and reached 1 billion by 2004. By 2006, there were over 2 billion GSM subscribers globally. This made it much larger than its competitor, CDMA. By the mid-2010s, GSM held over 90% of the market share.

As technology progressed, the GSM standard evolved to include more than just voice. It first expanded to include data through circuit-switched transport. Later, it added packet data transport via GPRS and then EDGE. In 1996, pre-paid GSM SIM cards were launched to make service more accessible.

The standard also operates on various frequency bands. Most 2G networks use the 900 MHz or 1800 MHz bands. However, in the United States and Canada, the 850 MHz and 1900 MHz bands are often used instead.

While GSM was a massive success, it is now being phased out. Starting in the late 2010s, many carriers began shutting down their 2G networks. Telstra in Australia was the first to decommission a GSM network in December 2016. This was followed by AT&T Mobility in the United States in 2017. GSM's specifications eventually passed to the 3GPP body in 2000. This group also developed 3G, 4G, and 5G standards. Although these newer generations are not part of the GSM standard, the term "GSM" is still used as a generic name for many mobile technologies.