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25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { font-family: “Liberation Serif”,”Times New Roman”,serif; font-size: 12pt; }p.cjk { font-family: “Noto Sans CJK SC Regular”; font-size: 12pt; }p.ctl { font-family: “FreeSans”; font-size: 12pt; }a:link { }AIM:Toprepare the case study for GSM(Global System for MobileCommunications).SoftwareRequired:Internet,MS WordTheory:Introduction:GSM(GlobalSystem for Mobile Communications)is a standard developed by the European Telecommunications StandardsInstitute (ETSI) to describe the protocols for second-generationdigital cellular networks used by mobile devices such as tablets, ithas become the global standard for mobile communications.
“GSM”is a trademark owned by the GSM Association. It may also refer to the(initially) most common voice codec used, Full Rate.According tothe GSM Association (GSMA), which represents the interests of theworldwide mobile communications industry, it’s approximated that 80%of the world uses GSM technology when placing wireless calls.Features:Improved spectrum efficiency International roaming Compatibility with integrated services digital network (ISDN) Support for new services. SIM phonebook management Fixed dialing number (FDN) Real time clock with alarm management High-quality speech Uses encryption to make phone calls more secure Short message service (SMS) BlockDiagram:Thefollowing diagram shows the GSM network along with the addedelements:Components:Thegeneric GSM network architecture is composed of three subsystems asthe Radio Subsystem (RSS), the network and Switching Subsystem (NSS)and the Operation Subsystem (OSS). The subscriber carries the MobileStation, which is part or RSS. RadioSubstation (RSS)TheRSS consists of the components that are necessary in order toallocate the radio resources to the individual subscribers.
Itprincipally consists of the mobile terminals (mobile phone or mobilestation, MS) and the base station subsystem (BSS).Networkswitching subsystem(NSS)(or GSMcore network)Itis the component of a GSM system that carries out call switching andmobility management functions for mobile phones roaming on thenetwork of base stations. It is owned and deployed by mobile phoneoperators and allows mobile devices to communicate with each otherand telephones in the wider public switched telephone network (PSTN).The architecture contains specific features and functions which areneeded because the phones are not fixed in one location.TheNSS originally consisted of the circuit-switched core network, usedfor traditional GSM services such as voice calls, SMS, and circuitswitched data calls. It was extended with an overlay architecture toprovide packet-switched data services known as the GPRS core network.This allows mobile phones to have access to services such as WAP, MMSand the Internet.MobileStation (MS)MSis basically mobile equipment (the handset) which comprises all userequipment and software needed for mobile communication and a smartcard called the Subscriber Identity Module (SIM).
The MS, whichcontain a SIM, card in the form of a very small chip bside theequipment.TheSubscriber Identity Module (SIM) contains all subscriber informationnecessary for identifying GSM subscriber. Broadly, it holds asubscriber’s International Mobile Subscriber Identity (IMSI),authentication key and algorithm. SIM is independent of the device orhandset In which it is being used because an MS can be identified viaInternational Mobile Equipment Identity (IMEI).
As soon as the SIM isinserted into handset, it becomes immediately programmed for use.Therefore, it can be inserted into any handset. Typically, mobilestations have transmitted power from 2 W to 1W depending upon thecell size, If cell size is smaller, the transmitted power will beless.HomeLocation Register (HLR)The HLR in telecom is thereference database for subscriber parameters.
Various identificationnumbers and addresses are stored, as well as authenticationparameters. This information is entered into the database by thenetwork provider when a new subscriber is added to the system. The Basic Parameters stored in theHLR in telecom are listed below:Subscriber ID (IMSI and MSISDN) Current Subscriber VLR (Current Location) Supplementary Services Subscriber to (Caller Tone, Missed Call Alert, Any Other Services etc.) Subscriber Status (Registered or Deregistered) Authentication Key and AUC Functionality Mobile Subscriber Roaming Number Visitor Location Register (VLR)The VLR contains a copy of most ofthe data stored at the HLR. It is, however, temporary data whichexists for only as long as the subscriber is “active” in theparticular area covered by the VLR.
The VLR database will thereforecontain some duplicate data as well as more precise data relevant tothe subscriber remaining within the VLR coverage (here coverage meansstatus of customer of last lac location area code updation )The additional data stored in theVLR in telecom is listed below:Location Area Identity (LAI). Temporary Mobile Subscriber Identity (TMSI). Mobile Station Roaming Number (MSRN). Mobile status (busy/free/no answer etc.). Operationand Support System(OSS)Theimplementation of OMC is called the operation and support system(OSS).
The OSS is the functional entity from which the networkoperator monitors and controls the system. The purpose of OSS is tooffer the customer cost-effective support for centralized, regional,and local operational and maintenance activities that are requiredfor a GSM network. An important function of OSS is to provide anetwork overview and support the maintenance activities of differentoperation and maintenance organizations.AuthenticationCenter (AUC) SeparateAUC is defined to protect User ID and data transmission. A databasewhich contains the International Mobile Subscriber Identity (IMSI)the Subscriber Authentication key (Ki), and the defined algorithmsfor encryption.EquipmentIdentity Register (EIR)Adatabase which contains information about the identity of mobileequipment in order to prevent calls from stolen, unauthorized, ordefective mobile stations.
GSMServices:GSMservices are classified as either teleservices or data services.Teleservices include standard mobile telephony and mobile-originatedtraffic. Data services include computer to computer communication andpacket switched traffic. User services may be divided into threemajor categories.A.
Telephone services:These include emergency calling and facsimile. GSM also supportsVideotex and Teletex.B.
Bearer services or dataservices: These are limited to layer 1,2 and 3 of the opensystem interconnection (OSI) reference model. Supported servicesinclude packet switched protocols and data rates from 300bps to 9.6kbps.
Data may be transmitted using transparent or non transparentmode.C. Supplementary ISDNservices: these are digital in nature and include calldiversion, closed user groups and caller identification, and are notavailable in analog mobile networks. Supplementary services alsoinclude short messaging service (SMS) which allows GSM subscribersand base station to transmit alphanumeric pages of limited lengthwhile simultaneously carrying normal voice traffic.
SMS provides cellbroadcast also can be used for safety and advisory applications suchas the broadcast of highway or weather information to all GSMsubscribers.Conclusion:Thus,we have studied and prepared the case study for GSM(GlobalSystem for Mobile Communications).
