GSM stands for
Global System for Mobile Communications. Just like computers, mobile phones have evolved over time. There were first generation mobile phones in the 70's, there are
2nd generation mobile phones in the 80's and 90's, and now there are 3rd gen phones which are about to enter the
Indian market. GSM is called a 2nd generation, or 2G communications technology.
GSM
Network Architecture
- the
GSM network architecture consists of different elements that all interact together to form the overall GSM system. These include elements like the base-station, controller,
MSC, AuC,
HLR,
VLR, etc.
GSM TUTORIAL INCLUDES
GSM tutorial / introductionHistoryNetwork architectureInterfacesRadio access networkFramesFrequency bands and allocationsPower class, control & amplifiersPhysical & logical channelsCodecs / vocodersHandover / handoff
The GSM technical specifications define the different elements within the GSM network architecture. It defines the different elements and the ways in which they interact to enable the overall system operation to be maintained.
The GSM network architecture is now well established and with the other later cellular systems now established and other new ones being deployed, the basic GSM network architecture has been updated to
interface to the network elements required by these systems.
Despite the developments of the newer systems, the basic GSM system architecture has been maintained, and the network elements described below perform the same functions as they did when the original GSM system was launched in the early
1990s.GSM network architecture elements
The GSM network architecture as defined in the GSM specifications can be grouped into four main areas:
Mobile station (MS)
Base-Station Subsystem (
BSS)
Network and Switching Subsystem (
NSS)
Operation and
Support Subsystem (
OSS)
The different elements of the GSM network operate together and the user is not aware of the different entities within the system.
Mobile station
Mobile stations (MS), mobile equipment (ME) or as they are most widely known, cell or mobile phones are the section of a GSM cellular network that the user sees and operates. In recent years their size has fallen dramatically while the level of functionality has greatly increased. A further advantage is that the time between charges has significantly increased.
There are a number of elements to the cell phone, although the two main elements are the main hardware and the
SIM.
The hardware itself contains the main elements of the mobile phone including the display, case, battery, and the electronics used to generate the signal, and process the data receiver and to be transmitted. It also contains a number known as the
International Mobile Equipment Identity (
IMEI). This is installed in the phone at manufacture and "cannot" be changed. It is accessed by the network during registration to check whether the equipment has been reported as stolen.
The SIM or
Subscriber Identity Module contains the information that provides the identity of the user to the network. It contains are variety of information including a number known as the
International Mobile Subscriber Identity (
IMSI).
Base Station Subsystem (BSS)
The Base Station Subsystem (BSS) section of the GSM network architecture that is fundamentally associated with communicating with the mobiles on the network. It consists of two elements:
Base Transceiver Station (
BTS): The BTS used in a GSM network comprises the radio transmitter receivers, and their associated antennas that transmit and receive to directly communicate with the mobiles. The BTS is the defining element for each cell. The BTS communicates with the mobiles and the interface between the two is known as the
Um interface with its associated protocols.
Base Station Controller (
BSC): The BSC forms the next stage back into the GSM network. It controls a group of BTSs, and is often co-located with one of the BTSs in its group. It manages the radio resources and controls items such as handover within the group of BTSs, allocates channels and the like. It communicates with the BTSs over what is termed the
Abis interface.
- published: 05 Dec 2014
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