The GSM logo is used to identify compatible devices and equipment. The dots symbolize three clients in the home network and one cellular system in mobile communication pdf client.
Europe, and EU rules were passed to make GSM a mandatory standard. The decision to develop a continental standard eventually resulted in a unified, open, standard-based network which was larger than that in the United States. In February 1987, Europe produced the very first agreed GSM Technical Specification. The MoU drew in mobile operators from across Europe to pledge to invest in new GSM networks to an ambitious common date.
900 MHz spectrum band for GSM. Work began in 1991 to expand the GSM standard to the 1800 MHz frequency band and the first 1800 MHz network became operational in the UK by 1993, called and DCS 1800. In 1995, fax, data and SMS messaging services were launched commercially, the first 1900 MHz GSM network became operational in the United States and GSM subscribers worldwide exceeded 10 million. Pre-paid GSM SIM cards were launched in 1996 and worldwide GSM subscribers passed 100 million in 1998. GPRS-compatible handsets became available for sale. 3G technology that is not part of GSM.
Worldwide GSM subscribers exceeded 500 million. GSM network in the 800 MHz frequency band became operational. 2003, and the number of worldwide GSM subscribers exceeded 1 billion in 2004. 3G technologies, not part of GSM. Worldwide GSM subscribers exceeded three billion in 2008. 5 billion people across more than 212 countries and territories, making GSM the most ubiquitous of the many standards for cellular networks. GSM, for the first time, set a common standard for Europe for wireless networks.
It was also adopted by many countries outside Europe. This allowed subscribers to use other GSM networks that have roaming agreements with each other. The common standard reduced research and development costs, since hardware and software could be sold with only minor adaptations for the local market. 2G GSM network on December 1, 2016, the first mobile network operator to decommission a GSM network. Singapore shut down 2G services entirely in April 2017. The coverage area of each cell varies according to the implementation environment. Femtocells are cells designed for use in residential or small business environments and connect to the service provider’s network via a broadband internet connection.
Umbrella cells are used to cover shadowed regions of smaller cells and fill in gaps in coverage between those cells. Cell horizontal radius varies depending on antenna height, antenna gain, and propagation conditions from a couple of hundred meters to several tens of kilometres. These are typically deployed when significant call capacity is needed indoors, like in shopping centers or airports. However, this is not a prerequisite, since indoor coverage is also provided by in-building penetration of the radio signals from any nearby cell. GSM networks operating in the 900 MHz or 1800 MHz bands.
In rare cases the 400 and 450 MHz frequency bands are assigned in some countries because they were previously used for first-generation systems. Europe operate in the 2100 MHz frequency band. Half-rate channels use alternate frames in the same timeslot. This allows the user to retain his or her information after switching handsets.
Alternatively, the user can also change operators while retaining the handset simply by changing the SIM. A subscriber may usually contact the provider to remove the lock for a fee, utilize private services to remove the lock, or use software and websites to unlock the handset themselves. It is possible to hack past a phone locked by a network operator. GSM was intended to be a secure wireless system.
However, GSM is vulnerable to different types of attack, each of them aimed at a different part of the network. GSM uses several cryptographic algorithms for security. 2 is weaker and used in other countries. The system supports multiple algorithms so operators may replace that cipher with a stronger one.