GSM: The European Standard for Mobile Telephony Presented by Rattan Muradia Requirement for course CSI 5171 Presented by Rattan Muradia Requirement for course CSI 5171

Presentation Objective No discussion of mobile network concepts already covered (MSC, BSC, HLR, VLR, registration, call setup, roaming, handover, OSS etc..) No discussion of mobile network concepts already covered (MSC, BSC, HLR, VLR, registration, call setup, roaming, handover, OSS etc..) GSM Architecture GSM Architecture Focus on features specific to GSM Focus on features specific to GSM Provide basic information required for presentations on CAMEL, GPRS and UMTS Provide basic information required for presentations on CAMEL, GPRS and UMTS

Evolution of Digital Mobile Systems 1st Generation, Analogue Cellular - AMPS, ETACS, NMT, C-NET... 1st Generation, Analogue Cellular - AMPS, ETACS, NMT, C-NET... 2nd Generation, Digital Cellular - GSM, PDC, DAMPS, CDMA... 2nd Generation, Digital Cellular - GSM, PDC, DAMPS, CDMA... 2nd Generation Cordless - DECT, PHS... 2nd Generation Cordless - DECT, PHS... 2nd Generation Satellite - Iridium, Globalstar.. 2nd Generation Satellite - Iridium, Globalstar Generation GPRS Generation GPRS... 3rd Generation Universal - IMT-2000, UMTS 3rd Generation Universal - IMT-2000, UMTS

Digital Mobile Systems

GSM Overview Developed in Europe Developed in Europe One of first ‘intelligent’ networks with distributed processing One of first ‘intelligent’ networks with distributed processing International roaming International roaming 174 countries, 647 million subscribers 174 countries, 647 million subscribers 67% of world wireless market share 67% of world wireless market share

GSM Network Mobile Station (MS) Mobile Station (MS) Base Station Subsystem (BSS) Base Station Subsystem (BSS) Network and Switching Subsystem (NSS) Network and Switching Subsystem (NSS) Operation and Support Subsystem (OSS) Operation and Support Subsystem (OSS)

GSM Network Architecture SOURCE: UWC INTERFACE TO LAND TELEPHONE NETWORKS HIERARCHY OF CELLS CELL TRANSMITTER & RECEIVER PHONE SIM: IDENTIFIES A SUBSCRIBER LIST OF ROAMING VISITORS LIST OF SUBSCRIBERS IN THIS AREA STOLEN, BROKEN CELLPHONE LIST ENCRYPTION, AUTHENTICATION

GSM Reference Model

GSM Protocol Stack

GSM Address and Identifiers International Mobile Subscriber Identity (IMSI) International Mobile Subscriber Identity (IMSI) – 3 digit Mobile Country Code + 2 digit Mobile Network Code + 10 digit Mobile Subscriber Identification Number International Mobile Equipment Identity (IMEI) International Mobile Equipment Identity (IMEI) – 19 digit unique ID, used by air interface, stored in EIR Mobile Subscriber ISDN Number (MSISDN) Mobile Subscriber ISDN Number (MSISDN) – upto 3 digit Country Code digit national Destination Code + max 10 digit Subscriber Number – mapped to MSRN by HLR Mobile Station Roaming Number (MSRN) Mobile Station Roaming Number (MSRN) – temporary ISDN number assigned by VLR

GSM Mobile Station Each MS identified by IMEI Each MS identified by IMEI In addition to the physical equipment common to most MS, GSM equipment includes a SIM. In addition to the physical equipment common to most MS, GSM equipment includes a SIM. Subscriber Identity Module (SIM) provides true mobility. Access to subscribed services: Subscriber Identity Module (SIM) provides true mobility. Access to subscribed services: – regardless of location of the terminal – regardless of use of specific terminal SIM contains IMSI, secret key for authentication + more information SIM contains IMSI, secret key for authentication + more information

GSM Databases Equipment Identity Register (EIR) Equipment Identity Register (EIR) – contains list of valid mobile equipment (IMEI) – an IMEI can be marked invalid if MS is stolen, unauthorized or defective Authentication Center (AuC) Authentication Center (AuC) – protected database that stores authentication and encryption parameters – used to verify user identity and ensure confidentiality of each call

GSM Call Delivery

GSM Services Patterned after ISDN Patterned after ISDN Bearer Services Bearer Services – sync, async data transport, represent layers 1-3 – also used by higher layers to offer teleservices Teleservices Teleservices – voice, SMS, FAX, Teletext etc.. Supplementary Services Supplementary Services – modify or supplement teleservices

GSM Services - Phase 1 Offered by all operators in 1991.

GSM Services - Phase 2 Introduced in Major rework of standards. Backward compatible. More supplementary services.

GSM Phase 2+ Increased globalization using SIM, multiband systems and terminals Increased globalization using SIM, multiband systems and terminals Phase 2+ Phase 2+ – increase network capacity via spectral efficiency – improve voice quality – group call (party line) – integration of packet services (on air interface) and higher data speeds (GPRS) – expand supplementary services (SMS Forwarding, Multiple Subscriber profile, Call Xfer etc..) (see GPRS presentation by Miao Lu and Nancy Samaan on April 5th).

GSM Phase 2+ No complete revision of standards in Phase 2+ No complete revision of standards in Phase 2+ Each subject area treated separate, allowed to implement and introduce independently Each subject area treated separate, allowed to implement and introduce independently Standardize mechanisms for service introduction, not complete services Standardize mechanisms for service introduction, not complete services Reduce time-to-market, allow differentiation Reduce time-to-market, allow differentiation GSM already has similarities with IN (MSC=SSP, HLR=SCP, SS7 signaling) GSM already has similarities with IN (MSC=SSP, HLR=SCP, SS7 signaling) Convergence of GSM and IN - CAMEL Convergence of GSM and IN - CAMEL (see CAMEL presentation by Tina Deng and Yinyan Zhou on April 2th).

Beyond GSM - 3G Road to UMTS/IMT2000 New generation of mobile systems based on IP New generation of mobile systems based on IP Must support large number of subscribers Must support large number of subscribers Wide range of voice and data services Wide range of voice and data services Build on existing GSM infrastructure as much as possible. Build on existing GSM infrastructure as much as possible. Higher bandwidth for multimedia applications Higher bandwidth for multimedia applications – new radio interface – better use of spectrum (see IMT2000 presentation by Mingdi Zhao and Wei Lin on April 9th).

Questions?Questions?

GSM/GPRS/UMTSGSM/GPRS/UMTS Backup slide 1

GSM Network Architecture backup slide SOURCE: UWC Backup slide 2

GSM Protocol Stack Backup slide 3