3GPP
3rd Generation Partnership Project A group of standards organizations that develop protocols for mobile telecommunications.
CoSP
Communication Service Provider – A telecom service provider that offers telecommunications services or some combination of information and media services, content, entertainment and application services over a telecom network.
GSMA
Global System for Mobile Communications Association – Organization that allocates official IMEI number ranges to all manufacturers of 3GPP compliant devices and records these ranges and device model information in a database.
IETF
The Internet Engineering Task Force – Internet Engineering Task Force is a standards organization for the Internet and is responsible for the technical standards that make up the Internet protocol suite.
MNO
Mobile Network Operator – A mobile operator/carrier that owns the cellular network infrastructure.
MVNO
Mobile Virtual Network Operator – A wireless communications services provider that does not own the wireless network infrastructure over which it provides services to its customers. Read more at Wikipedia