Global system for Mobile Communications

TOPICS Communication – PSTN Communication – PLMN Wired Vs Wireless SAN 7 Cell Cluster Structure System Architecture

GSM : It is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation (2G) digital cellular networks used by mobile phones, first deployed in Finland in July 1991.As of 2014 it has become the de facto global standard for mobile communications – with over 90% market share, operating in over 219 countries and territories.

Communication – PSTN Subscriber Inter-Exchange Line Junction (2W) Telephone Exchanges Subscriber Line (2W) Inter-Exchange Junction

Communication - PLMN BSC BTS MS Telephone Exchange Subscriber Line (2W) Inter-Exchange Junction Mobile Switching Centre (MSC) BSC BTS MS

ONLY a window of RF Spectrum is available Wired Vs Wireless SAN Mobile Switching Centre (MSC) BSC BTS MS ONLY a window of RF Spectrum is available RF Channels Wireless Network Frequency/Time Division Multiplexing Limited RF spectrum and hence RF channels assigned on demand Dynamically changing tele density in each area. Dynamic Network snapshots.

Lay as much cable as needed to meet the demand. Wired Vs Wireless SAN Wired Network Lay as much cable as needed to meet the demand. Telephone Exchange Subscriber Line (2W) Space Division Multiplexing Available space much more than required and hence dedicated access to each. Tele density of an area does not pose any problem. Static Network snapshots.

7 Cell Cluster Structure F1 F7 F2 F3 F4 F5 F6 F4 F1 F5

GSM - Cell layout F3 F F3 F3 Farthest Separation F2 F4 F2 F1 F4 F7 F1

System Architecture Functional Architecture broadly divided into six parts: Mobile Station. Base Station Subsystem (BSS). Network Switching Subsystem (NSS). Operation and Maintenance Subsystem. Enhanced Services System Billing and Customer Care System

MOBILE STATIONS : Mobile Station is really two distinct entities. Mobile equipment or Mobile terminal. SIM Card.

Every terminal has an International Mobile Equipment Identity (IMEI). MOBILE TERMINAL : Different terminals distinguished principally by their power and application. Fixed terminals – 20W Portable terminals for cars – 8W Handheld terminals – 2W Sophisticated terminals – 0.8W Every terminal has an International Mobile Equipment Identity (IMEI).

SIM : SIM provides Personal Mobility. Holds a unique identifier called International Mobile Subscriber Identity (IMSI), Service profile, Secret key for authentication, etc. Provides user access to all subscribed services. SIM makes the terminal operational. Can be password protected by a 4 to 8 digit Personal Identification Number.

Base Station Subsystem : BSS connects the MS and the NSS. Composed of three parts: The Base Transceiver Station (BTS) also called Base Station (BS) Transcoder and. Base Station Controller (BSC). BSS provides the radio interface functions. Completely digital.

Base Transceiver Station (BTS) : BTS houses the radio transceivers that define a cell. Handles the radio-link protocols with the Mobile Station Each BTS can support a number of transceivers depending on the density of subscribers in the cell. Needs to be rugged, reliable, portable.

Base Station Controller : BSC manages the radio resources for one or a group of BTSs. Handles radio-channel setup, frequency hopping, handovers, and control of the RF power levels. Establishes connection between the mobile station and the MSC.

BSS Connectivity : BSC BTS To MSC XCDR

Network & Switching Subsystem : Manages the communication between the mobile users and other users. Provides all the functionality needed to handle a mobile subscriber such as: Registration. Authentication and security. Location updating. Handovers and Routing to roaming subscribers.

Network & Switching Subsystem : Central component is the MSC (Mobile Services Switching Centre). It performs the switching functions of the network. Gateway Mobile Services Switching Centre interfaces between the mobile network and PSTN.

Network & Switching Subsystem : Services provided in conjunction with four intelligent databases. Home Location Register (HLR) Visitor Location Register (VLR) Authentication Centre (AuC) Equipment Identity Register (EIR)

Operation & Support Subsystem : OMS comprises of : Operation and Maintenance Centre (OMC) for Radio OMC-R. OMC for Switch OMC-S Configures, controls and monitors the GSM system. Controls the traffic load in BSSs.

Enhanced Services System : Unified Messaging Services (UMS) Voice Mail (VM) FAX Mail (FM) E-Mail (EM) Short Message Service (SMS) Wireless Application Protocol (WAP) Intelligent Network (IN)

Billing & Customer Care System : Mediation Device Interconnect Billing Subsystem Billing Subsystem Rating Module Billing Module Roaming settlement subsystem Customer Service Module Order Management Module Smart Card Handling Module Service Provisioning Subsystem Networking Subsystem Printing Subsystem

Base Station Subsystem GSM Network Overview A Base Station Subsystem Network Subsystem OMC MSC HLR EIR VLR AuC BSC Um Abis BTS ME SIM PSTN ISDN PSPDN CSPDN Mobile Station

Thank You a presentation by Srijan Dubey S3 E.C. Roll No. 57