Definition - What does Carrier mean?
A carrier, in the context of cellular technology is a company that provides mobile services. The term “carrier” is short for wireless carrier. Other terms used that refer to the same thing include mobile network operator, mobile phone operator, mobile operator, cellular company, and wireless service provider.
Techopedia explains Carrier
A company aspiring to become a carrier normally starts by applying for a radio spectrum license from the government. The radio spectrum or frequency range that it applies for depends on the kind of technology the company wishes to employ. GSM (Global System for Mobile Communications) utilizes a frequency range different from CDMA (Code Division Multiple Access).
These frequency ranges are usually offered by the government to interested parties through auctions. When the company succeeds in its bid to become a wireless carrier, it then has to build the necessary infrastructure in order to offer mobile services to its subscribers. These services can range from voice, SMS, MMS, to Web access.
Some of the biggest carriers in the world (based on the number of subscribers) include China Mobile, Vodafone, SingTel, America Movil, and Telefonica. In the US, the largest carriers are Verizon and AT&T.