GSM

SIM

A subscriber identity module is a removable smart card for mobile phones so that the user can have access to all subscribed services irrespective of both the location of the terminal and the use of a specific terminal.

AGCH

Access Grant Channel(AGCH) AGCH is the channel from the network to the Mobile Subscriber (MS) in the downlink of GSM system. It carry information by which mobile will determine whether the access to the network has been allowed or denied.

AuC

Authentication Center (AUC) The Authentication Center is a protected database that stores a copy of the secret key stored in each subscriber's SIM card, which is used for authentication and ciphering of the radio channel.

BSC

Base Station Controller The BSC manages the radio resources for one or more BTSs.

BTS

Base Transceiver Station • houses the radiotransceivers of the cell and handles the radio-link protocols with the mobile

BSIC

Base Transceiver Station Identity Code is a code used in GSM to uniquely identify a base station

BCCH

Broadcast Control Channel The BCCH carries a repeating pattern of system information messages that describe the identity, configuration and available features of the base transceiver station (BTS).

FACCH

Fast Associated Control Channel In GSM, FACCH is used to exchange information between GSM Mobile Station(MS) and Base Transceiver Station(BTS) more quickly than possible with SACCH.

FCH

Frequency correction channel It is a downlink channel and carry continuous wave signal which helps mobile find the frequency offset between BTS and MS.

GMSC

Gateway MSC that is used to route calls outside the mobile network.

GCI/GCID

Global Cell Identity LAI+CI rom MCC, you can figure out in which country the cell is located. From MNC, you can figure out which network operator it belongs to. From LAC, you can figure out which location area it belongs to. From CI (Cell Identity : two octets), you can identify the exact one cell.

GSM

Global System for Mobile is a digital mobile telephony system that uses a variation of time division multiple access (TDMA) and is the most common system in the world

HLR

Home Location Register (HLR) The HLR is a database used for storage and management of subscriptions

IMEI

International Mobile Equipment Identity is a unique 15-digit serial number that uniquely identifies a mobile phone. MS

IMSI

International Mobile Subscriber Identity identify the user of a cellular network and is a unique identification associated with all cellular networks.

LAC

Location Area Code is a unique number of current location area. A location area is a set of base stations that are grouped together to optimize signalling.

MS

Mobile Station is a user equipment and software needed for communication with a mobile network

MSC

Mobile Switching Center (MSC), performs the switching of calls between the mobile and other fixed or mobile network users, as well as the management of mobile services such as authentication.

PCH

PCH refers to paging channel. Mobile in idle mode monitors PCH for paging continuously and check for its address. It is mainly used by network to page or alert mobile for mobile terminated call from another calling mobile.

PLMN

Public Land Mobile Network is identified by the Mobile Country Code (MCC) and the Mobile Network Code (MNC The area covered by one network operator is called the Public Land Mobile Network (PLMN)

PSTN

Public Switched T elephone Network, Basically the normal phone network, or land line.

RACH

Random Access Channel This channel RACH is used by Mobile to access the GSM network during call set-up time

SACCH

Slow Associated Control Channel In the downlink, SACCH is used to convey transmit power level control instructions and timing advance information to the GSM mobile. In the uplink, SACCH carries received signal strength, TCH quality information and measurement report of neighboring cells etc.

SDCCH

Standalone Dedicated Control Channel(SDCCH) SDCCH is a signalling channel exist between GSM Mobile and GSM BTS. This SDCCH channel exist independent of whether TCH exist or not. It always exist and no frame stealing is needed here.

SCH

Synchronization Channel The purpose of the SCH is to allow the mobile station (handset) to quickly identify a nearby cell (a BTS) and synchronize to that BTS's TDMA structures.

TMSI

Temporary Mobile Subscriber Identity; covers the IMSI to prevent over-the-air interception and tracing

EIR

The Equipment Identity Register (EIR) is a database that contains a list of all valid mobile equipment on the network

TAC

The Type Allocation Code (TAC) is the initial eight-digit portion of the 15-digit IMEI and 16-digit IMEISV codes used to uniquely identify wireless devices. The Type Allocation Code identifies a particular model (and often revision) of wireless telephone for use on a GSM, UMTS or other IMEI-employing wireless network.

TCH

Traffic Channel - Traffic channel in GSM carry user speech or data as other technology.

VLR

Visitor Location Register (VLR) The VLR is a database that contains temporary information about subscribers that is needed by the MSC in order to service visiting subscribers.