Mobile phone operator

A mobile phone operator or wireless provider is a telephone company that provides services for mobile phone users. The operator gives a SIM card to the customer who inserts it into the mobile phone to gain access to the service. There are two types of mobile operator: a mobile network operator (MNO) which owns the underlying network and spectrum assets required to run the service. a mobile virtual network operator (MVNO) which buys wholesale service from an MNO and sells on to its own customers. The world's largest individual mobile operator by subscribers is China Mobile with over 500 million mobile phone subscribers.[1] Over 50 mobile operators have over 10 million subscribers each, and over 150 mobile operators had at least one million subscribers by the end of 2009.[2] In February 2010, there were 4.6 billion mobile phone subscribers, a number that is estimated to grow.Total mobile?cellular subscriptions reached almost 6 billion by end 2011, corresponding to a global penetration of 86%. A telephone company, also known as a telco, telephone service provider,[1] or telecommunications operator, is a kind of communications service provider (CSP) (more precisely a telecommunications service provider or TSP) that provides telecommunications services such as telephony and data communications access. Many telephone companies were at one time government agencies or privately owned but state-regulated monopolies. The government agencies are often referred to, primarily in Europe, as PTTs (postal, telegraph and telephone services). Telephone compan es are common carriers, and in the United States are also called local exchange carriers. With the advent of mobile telephony, telephone companies now include wireless carriers, or mobile network operators. Most telephone companies now also function as internet service providers (ISPs), and the distinction between a telephone company and an ISP may disappear completely over time, as the current trend for supplier convergence in the industry continues. A subscriber identity module or subscriber identification module (SIM) is an integrated circuit that securely stores the international mobile subscriber identity (IMSI) and the related key used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers). A SIM is embedded into a removable SIM card, which can be transferred between different mobile devices. SIM cards were first made the same size as a credit card (85.60 mm ? 53.98 mm ? 0.76 mm). The development of physically smaller mobile devices prompted the development of a smaller SIM card, the mini-SIM card. Mini-SIM cards have the same thickness as full-size cards, but their length and width are reduced to 25 mm ? 15 mm. A SIM card contains its unique serial number (ICCID), international mobile subscriber identity (IMSI), security authentication and ciphering information, temporary information related to the local network, a list of the services the user has access to and two passwords: a personal identification number (PIN) for ordinary use and a personal unblocking code (PUK) for PIN unlocking.