GSM stands for Global System for Mobile Communications. It is a standard developed to describe protocols for second-generation (2G) digital cellular networks used by mobile devices. Here are some key points about GSM:
1. Technology and Frequency Bands:
GSM operates on multiple frequency bands, including 900 MHz and 1800 MHz in most parts of the world and 850 MHz and 1900 MHz in North America.
2. Network Architecture:
GSM uses a combination of time division multiple access (TDMA) and frequency division multiple access (FDMA) to divide each frequency band into multiple channels, which can support multiple simultaneous calls.
3. SIM Cards:
GSM introduced the use of Subscriber Identity Modules (SIM cards), which store user information and can be transferred between different GSM-compatible phones.
4. Global Roaming:
GSM is widely adopted worldwide, enabling users to roam and use their mobile phones in different countries, provided the network is compatible.
5. Evolution:
GSM technology has evolved over time to support higher data rates and more advanced features, leading to the development of GPRS (General Packet Radio Service), EDGE (Enhanced Data Rates for GSM Evolution), and eventually 3G, 4G, and 5G networks.
GSM remains one of the most widely used mobile communication standards globally.
