Telecom Radio Security Glossary

GSM
Global System for Mobile Communications, a standard developed to describe the protocols for second-generation (2G) digital cellular networks.
GPRS
General Packet Radio Service, a packet-oriented mobile data standard on the 2G and 3G cellular communication network's global system for mobile communications (GSM).
ARFCN
Absolute Radio Frequency Channel Number, a unique number used to identify a pair of radio carriers used for transmission and reception in GSM networks.
BTS
Base Transceiver Station, a piece of equipment that facilitates wireless communication between user equipment and a network.
BSC
Base Station Controller, a high-capacity switch that provides functions such as handover, cell configuration data, and control of radio frequency (RF) power levels in base transceiver stations.
MSC
Mobile Switching Center, the primary service delivery node for GSM/CDMA, responsible for routing voice calls and SMS as well as other services.
HLR
Home Location Register, a central database that contains details of each mobile phone subscriber that is authorized to use the GSM core network.
VLR
Visitor Location Register, a database of the temporary information about subscribers who have roamed into the particular area which it serves.
IMSI
International Mobile Subscriber Identity, a unique number associated with all GSM and Universal Mobile Telecommunications System (UMTS) network mobile phone users.
TMSI
Temporary Mobile Subscriber Identity, a temporary identification number that is sent instead of the IMSI to ensure a high level of security in GSM networks.