GSM and UMTS. Mobile phone subscribers worldwide. Development of mobile telecommunication systems. How does it work?

Transcription

1 Mobile phone subscribers worldwide approx. 1.7 bn Market GSM Overview Services Sub-systems Components GSM and UMTS UMTS/IMT-2000 Subscribers [million] GSM total TDMA total CDMA total PDC total Analogue total W-CDMA Total wireless Prediction (1998) year Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 1 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 2 Development of mobile telecommunication systems How does it work? CDMA TDMA FDMA CT0/1 AMPS NMT CT2 IS-136 TDMA D-AMPS GSM PDC IS-95 cdmaone GPRS cdma2000 1X EDGE IMT-FT DECT IMT-SC IS-136HS UWC-136 1G 2G 2.5G 3G IMT-DS UTRA FDD / W-CDMA IMT-TC HSDPA UTRA TDD / TD-CDMA IMT-TC TD-SCDMA IMT-MC cdma2000 1X EV-DO 1X EV-DV (3X) How can the system locate a user? Why don t all phones ring at the same time? What happens if two users talk simultaneously? Why don t I get the bill from my neighbor? Why can an Australian use her phone in Berlin? Why can t I simply overhear the neighbor s communication? How secure is the mobile phone system? What are the key components of the mobile phone network? Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 3 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 4

2 GSM GSM: Overview formerly: Groupe Spéciale Mobile (founded 1982) now: Global System for Mobile Communication Pan-European standard (ETSI, European Telecommunications Standardisation Institute) simultaneous introduction of essential services in three phases (1991, 1994, 1996) by the European telecommunication administrations (Germany: D1 and D2) seamless roaming within Europe possible today many providers all over the world use GSM (more than 200 countries in Asia, Africa, Europe, Australia, America) more than 1.2 billion subscribers in more than 630 networks more than 75% of all digital mobile phones use GSM (74% total) over 200 million S per month in Germany, > 550 billion/year worldwide (> 10% of the revenues for many operators) [be aware: these are only rough numbers ] Performance characteristics of GSM (wrt. analog sys.) Communication mobile, wireless communication; support for voice and data services Total mobility international access, chip-card enables use of access points of different providers Worldwide connectivity one number, the network handles localization High capacity better frequency efficiency, smaller cells, more customers per cell High transmission quality high audio quality and reliability for wireless, uninterrupted phone calls at higher speeds (e.g., from cars, trains) Security functions access control, authentication via chip-card and PIN Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 5 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 6 Disadvantages of GSM There is no perfect system!! no end-to-end encryption of user data no full ISDN bandwidth of 64 kbit/s to the user, no transparent B- channel B-channel (bearer channel): channel that carries main data reduced concentration while driving electromagnetic radiation GSM offers GSM: Mobile Services several types of connections voice connections, data connections, short message service multi-service options (combination of basic services) Three service domains Bearer Services Telematic Services Supplementary Services Enhancements for standard telephony service abuse of private data possible roaming profiles accessible high complexity of the system several incompatibilities within the GSM standards bearer services TE MT GSM-PLMN transit network source/ destination R, S (PSTN, ISDN) network (U, S, R) U m tele services TE Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 7 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 8

3 Bearer Services Telecommunication services to transfer data between access points Specification of services up to the terminal interface (OSI layers 1-3) Different data rates for voice and data (original standard) data service (circuit switched) synchronous: 2.4, 4.8 or 9.6 kbit/s asynchronous: bit/s data service (packet switched) synchronous: 2.4, 4.8 or 9.6 kbit/s asynchronous: bit/s transparent bearer services do not try to recover lost data non-transparent bearer services use protocols of layers 2 and 3 to implement error correction and flow control Today: data rates of approx. 50 kbit/s possible will be covered later! Tele Services I Telecommunication services that enable voice communication via mobile phones All these basic services have to obey cellular functions, security measurements etc. encrypted voice transmission, message services, and basic data communication with terminals as known from the PSTN or ISDN Offered services mobile telephony primary goal of GSM was to enable mobile telephony offering the traditional bandwidth of 3.1 khz Emergency number common number throughout Europe (112); mandatory for all service providers; free of charge; connection with the highest priority (preemption of other connections possible) Multinumbering several ISDN phone numbers per user possible according to the desired service Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 9 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 10 Tele Services II Supplementary services Additional services Non-Voice-Teleservices group 3 fax voice mailbox (implemented in the fixed network supporting the mobile terminals) electronic mail (MHS, Message Handling System, implemented in the fixed network)... Short Message Service (S) alphanumeric data transmission to/from the mobile terminal (160 characters) using the signaling channel, thus allowing simultaneous use of basic services and S (almost ignored in the beginning now the most successful add-on!) Services in addition to the basic services, cannot be offered stand-alone Similar to ISDN services besides lower bandwidth due to the radio link May differ between different service providers, countries and protocol versions Important services identification: forwarding of caller number suppression of number forwarding automatic call-back: keep trying the number until getting through conferencing with up to 7 participants locking of the mobile terminal (incoming or outgoing calls)... Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 11 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 12

4 Architecture of the GSM system (GSM-PLMN) Ingredients 1: Mobile Phones, PDAs & Co. GSM is a PLMN (Public Land Mobile Network) several providers setup mobile networks following the GSM standard within each country components (mobile station) BS (base station) (mobile switching center) LR (location register) subsystems RSS (radio subsystem): covers all radio aspects NSS (network and switching subsystem): call forwarding, handover, switching OSS (operation subsystem): management of the network The visible but smallest part of the network! Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 13 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 14 Ingredients 2: Antennas Ingredients 3: Infrastructure 1 Base Stations Cabling Microwave links Still visible cause many discussions Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 15 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 16

5 Ingredients 3: Infrastructure 2 GSM: overview Not visible, but comprise the major part of the network (also from an investment point of view ) NSS with OSS OMC, EIR, AUC VLR HLR G VLR fixed network BSC Management BSC Data bases RSS Switching units Monitoring Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 17 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 18 GSM: elements and interfaces GSM: system architecture radio subsystem network and switching subsystem fixed partner networks RSS U m radio cell BTS BSS radio cell U m ISDN PSTN BTS BTS BTS A bis BSC EIR A bis A BSC BSC SS7 HLR NSS OSS VLR EIR VLR HLR O AUC OMC G IWF signaling ISDN, PSTN PDN BTS BTS BSS BSC A IWF VLR ISDN PSTN PSPDN CSPDN Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 19 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 20

6 System architecture: radio subsystem System architecture: network and switching subsystem radio subsystem BTS BTS BTS BTS BSS U m A bis BSC BSC A network and switching subsystem Components (Mobile Station) BSS (Base Station Subsystem): consisting of BTS (Base Transceiver Station): sender and receiver BSC (Base Station Controller): controlling several transceivers Interfaces U m : radio interface A bis : standardized, open interface with 16/64 kbit/s user channels A: standardized, open interface with 64 kbit/s user channels network subsystem SS7 IWF EIR HLR VLR fixed partner networks ISDN PSTN ISDN PSTN PSPDN CSPDN Components (Mobile Services Switching Center): IWF (Interworking Functions) ISDN (Integrated Services Digital Network) PSTN (Public Switched Telephone Network) PSPDN (Packet Switched Public Data Net.) CSPDN (Circuit Switched Public Data Net.) Databases HLR (Home Location Register) VLR (Visitor Location Register) EIR (Equipment Identity Register) Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 21 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 22 Radio subsystem The Radio Subsystem (RSS) comprises the cellular mobile network up to the switching centers Components Base Station Subsystem (BSS): Base Transceiver Station (BTS): radio components including sender, receiver, antenna - if directed antennas are used one BTS can cover several cells Base Station Controller (BSC): switching between BTSs, controlling BTSs, managing of network resources, mapping of radio channels (U m ) onto terrestrial channels (A interface) BSS = BSC + sum(bts) + interconnection Mobile Stations () Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 23 GSM: cellular network segmentation of the area into cells cell use of several carrier frequencies not the same frequency in adjoining cells possible radio coverage of the cell idealized shape of the cell cell sizes vary from some 100 m up to 35 km depending on user density, geography, transceiver power etc. hexagonal shape of cells is idealized (cells overlap, shapes depend on geography) if a mobile user changes cells handover of the connection to the neighbor cell Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 24

7 GSM frequency bands Example coverage of GSM networks ( Type Channels Uplink [MHz] Downlink [MHz] T-Mobile (GSM-900/1800) Germany O 2 (GSM-1800) Germany GSM 850 (Americas) GSM 900 classical extended GSM 1800 GSM 1900 (Americas) 0-124, channels +49 channels AT&T (GSM-850/1900) USA Vodacom (GSM-900) South Africa GSM-R exclusive , channels Additionally: GSM 400 (also named GSM 450 or GSM 480 at / or / MHz - Please note: frequency ranges may vary depending on the country! - Channels at the lower/upper edge of a frequency band are typically not used Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 25 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 26 Base Transceiver Station and Base Station Controller Tasks of a BSS are distributed over BSC and BTS BTS comprises radio specific functions BSC is the switching center for radio channels Functions BTS BSC Management of radio channels X Frequency hopping (FH) X X Management of terrestrial channels X Mapping of terrestrial onto radio channels X Channel coding and decoding X Rate adaptation X Encryption and decryption X X Paging X X Uplink signal measurements X Traffic measurement X Authentication X Location registry, location update X Handover management X Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 27 Mobile station Terminal for the use of GSM services A mobile station () comprises several functional groups MT (Mobile Terminal): offers common functions used by all services the offers corresponds to the network termination (NT) of an ISDN access end-point of the radio interface (U m ) TA (Terminal Adapter): terminal adaptation, hides radio specific characteristics TE (Terminal Equipment): peripheral device of the, offers services to a user does not contain GSM specific functions SIM (Subscriber Identity Module): personalization of the mobile terminal, stores user parameters TE TA MT R S Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 28 U m

8 Network and switching subsystem NSS is the main component of the public mobile network GSM switching, mobility management, interconnection to other networks, system control mobility management: handovers between different BSSs Components Mobile Services Switching Center () controls all connections via a separated network to/from a mobile terminal within the domain of the - several BSC can belong to a Databases (important: scalability, high capacity, low delay) Home Location Register (HLR) central master database containing user data, permanent and semi-permanent (dynamic) data of all subscribers assigned to the HLR (one provider can have several HLRs) Visitor Location Register (VLR) local database for a subset of user data, including data about all user currently in the domain of the VLR avoid frequent HLR updates and long-distance signalling of user information Mobile Services Switching Center The (mobile switching center) plays a central role in GSM switching functions additional functions for mobility support management of network resources interworking functions via Gateway (G) integration of several databases Functions of a specific functions for paging and call forwarding termination of SS7 (signaling system no. 7) SS7: handles all signalling needed for connection setup, connection release and handover of connections to other s mobility specific signaling location registration and forwarding of location information provision of new services (fax, data calls) support of short message service (S) generation and forwarding of accounting and billing information Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 29 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 30 Operation subsystem The OSS (Operation Subsystem) enables network operation, management, and maintenance of all GSM subsystems Components Authentication Center (AUC) situated in a special protected part of the HLR generates user specific authentication parameters on request of a VLR authentication parameters used for authentication of mobile terminals and encryption of user data on the air interface within the GSM system Equipment Identity Register (EIR) registers GSM mobile stations and user rights stolen or malfunctioning mobile stations can be locked and sometimes even localized Operation and Maintenance Center (OMC) different control capabilities for the radio subsystem and the network subsystem traffic monitoring, status reports of network entities, subscriber and security management, or accounting and billing Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 31 frequency GSM - TDMA/FDMA GSM TDMA frame MHz 124 channels (200 khz) downlink MHz 124 channels (200 khz) uplink higher GSM frame structures GSM time-slot (normal burst) guard space tail user data S Training S user data tail 3 bits 57 bits 1 26 bits 1 57 bits 3 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 32 time guard space ms µs 577 µs

9 GSM TDMA/FDMA (Definitions) Normal burst data transmission GSM hierarchy of frames hyperframe: count each TDMA frame as input for encryption algorithm h 28 min s Tail set to 0 used to enhance the receiver performance Training sequence adapt the parameters of the receiver to the current path propagation characteristics select the strongest signal in case of multi-path propagation superframe multiframe s 120 ms (traffic) Flag S indicate whether the data field contains user or network control data ms (control) Guard space avoid overlapping with other bursts due to different path delays give the transmitter time to turn on and off frame slot burst ms 577 µs Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 33 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 34 GSM protocol layers for signaling U m A bis A BTS BSC CM MM RR LAPD m radio RR LAPD m radio BTSM LAPD PCM RR BTSM 16/64 kbit/s LAPD PCM BSSAP SS7 PCM CM MM BSSAP SS7 PCM 64 kbit/s / Mbit/s GSM protocol layers for signaling (Definitions) Layer 1 handles all radio-specific functions LAPD m offers reliable data transfer over connections re-sequencing of data frames flow control LAPD: LAPD m + synchronization and checksumming for error detection Radio resource management (RR) setup, maintenance, and release of radio channels Mobility management (MM) functions for registration, authentication, identification, location updating, and the provision of a temporary mobile subscriber identity (TI) Call management (CM) call control, short message service, and supplementary service Pulse code modulation (PCM) offer transparent 64 kbps digital channels BTS management (BTSM) functions of RR supported by BSC via BTS BSS application part (BSSAP) controls a BSS by Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 35 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 36

10 Mobile Terminated Call Mobile Originated Call 1: calling a GSM subscriber 2: forwarding call to G 3: signal call setup to HLR 4, 5: request RN from VLR 6: forward responsible to G 7: forward call to current calling station 8, 9: get current (availability) status of 10, 11: paging of 12, 13: answers 14, 15: security checks 16, 17: set up connection 4 HLR VLR PSTN G BSS BSS BSS , 2: connection request 3, 4: security check 5-8: check resources (free circuit) 9-10: set up call PSTN 6 5 G VLR BSS RN: mobile station roaming number Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 37 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 38 MTC/MOC 4 types of handover MTC BTS paging request channel request immediate assignment paging response authentication request authentication response ciphering command ciphering complete setup call confirmed assignment command MOC BTS channel request immediate assignment service request authentication request authentication response ciphering command ciphering complete setup call confirmed assignment command BTS BTS BTS BTS BSC BSC BSC assignment complete alerting connect connect acknowledge data/speech exchange assignment complete alerting connect connect acknowledge data/speech exchange Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 39 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 40

11 GSM Handover Handover decision Intra-cell handover change the carrier frequency Inter-cell, intra-bsc handover assign a new radio channel in the new cell and release the old one receive level BTS old receive level BTS old Inter-BSC, intra- handover perform handovers between cells controlled by different BSCs Inter- handover handover between two cells belonging to different s HO_MARGIN BTS old BTS new Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 41 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 42 Handover procedure measurement report HO command BTS old measurement result BSC old HO decision HO required HO command HO command HO access Link establishment clear command clear command clear complete clear complete HO request BSC new BTS new resource allocation ch. activation HO request ack ch. activation ack HO complete HO complete HO complete Security in GSM Security services access control/authentication user SIM (Subscriber Identity Module): secret PIN (personal identification number) SIM network: challenge response method challenge: random number; response: signed response (SRES) confidentiality voice and signaling encrypted on the wireless link (after successful authentication) anonymity temporary identity TI (Temporary Mobile Subscriber Identity) newly assigned at each new location update (LUP) encrypted transmission 3 algorithms specified in GSM A3 for authentication ( secret, open interface) A5 for encryption (standardized) A8 for key generation ( secret, open interface) A3 and A8: proprietary secret : A3 and A8 available via the Internet network providers can use stronger mechanisms Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 43 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 44

12 GSM - authentication GSM - key generation and encryption mobile network SIM mobile network (BTS) with SIM K i RAND RAND RAND K i K i RAND RAND RAND K i AC 128 bit 128 bit 128 bit 128 bit AC 128 bit 128 bit 128 bit 128 bit SIM A3 A3 SIM A8 A8 SRES* 32 bit SRES* =? SRES K i : individual subscriber authentication key SRES 32 bit SRES 32 bit SRES SRES: signed response cipher key BSS (BTS / BSC) K c 64 bit A5 data encrypted data K c 64 bit SRES data A5 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 45 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 46 Data services in GSM I Data transmission standardized with only 9.6 kbit/s advanced coding allows 14,4 kbit/s not enough for Internet and multimedia applications HSCSD (High-Speed Circuit Switched Data) mainly software update (upgrades in and ) bundling of several time-slots to get higher AIUR (Air Interface User Rate) (e.g., 57.6 kbit/s using 4 slots, 14.4 each) advantage: ready to use, constant quality, simple disadvantage: channels blocked for voice transmission still use the connection-oriented mechanisms of GSM AIUR [kbit/s] TCH/F4.8 TCH/F9.6 TCH/F Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 47 Data services in GSM II GPRS (General Packet Radio Service) packet switching using free slots only if data packets ready to send (e.g., 50 kbit/s using 4 slots temporarily) standardization 1998, introduction 2001 advantage: one step towards UMTS, more flexible disadvantage: more investment needed (new hardware) GPRS network elements GSN (GPRS Support Nodes): GGSN and SGSN GGSN (Gateway GSN) interworking unit between GPRS and PDN (Packet Data Network) SGSN (Serving GSN) supports the (location, billing, security) GR (GPRS Register) user addresses mapping between a mobile s identity and the PSPDN address Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 48

13 GPRS quality of service Examples for GPRS device classes Reliability class Lost SDU probability Duplicate SDU probability Out of sequence SDU probability Corrupt SDU probability Class 1 2 Receiving slots 1 2 Sending slots 1 1 Maximum number of slots 2 3 Delay SDU size 128 byte SDU size 1024 byte class mean 95 percentile mean 95 percentile 1 < 0.5 s < 1.5 s < 2 s < 7 s 2 < 5 s < 25 s < 15 s < 75 s 3 < 50 s < 250 s < 75 s < 375 s 4 unspecified Delay -- channel access delay, coding for error correction, and transfer delay in the fixed and wireless part of the GPRS network Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 49 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 50 GPRS user data rates in kbit/s GPRS architecture and interfaces SGSN G n Coding scheme 1 slot 2 slots 3 slots 4 slots 5 slots 6 slots 7 slots 8 slots BSS SGSN GGSN PDN CS U m G b G n G i CS CS-3 CS HLR/ GR VLR EIR Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 51 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 52

14 GPRS protocol architecture GPRS protocol architecture (Definitions) U BSS m G SGSN b G GGSN n G i Base station subsystem GPRS protocol (BSSGP) Convey routing and QoS-related information between BSS and SGSN apps. IP/X.25 SNDCP LLC SNDCP LLC GTP UDP/TCP IP/X.25 GTP UDP/TCP Subnetwork dependent convergence protocol (SNDCP) adapt to different characteristics of the underlying networks between SGSN and transport between GSNs within the GPRS backbone RLC RLC BSSGP BSSGP IP IP MAC MAC FR FR L1/L2 L1/L2 radio radio Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 53 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 54 Original Goals for 3G UMTS and IMT-2000 Establish a common worldwide communication system allowed for terminal and user mobility Support the idea of universal personal telecommunication Proposals for IMT-2000 (International Mobile Telecommunications) UWC-136, cdma2000, WP-CDMA UMTS (Universal Mobile Telecommunications System) from ETSI UMTS UTRA (was: UMTS, now: Universal Terrestrial Radio Access) enhancements of GSM EDGE (Enhanced Data rates for GSM Evolution): GSM up to 384 kbit/s enhanced modulation schemes CAMEL (Customized Application for Mobile Enhanced Logic) intelligent network support VHE (Virtual Home Environment) fits into GMM (Global Multimedia Mobility) initiative from ETSI provide an architecture to integrate mobile and fixed terminals, many different access networks, and core transport networks requirements min. 144 kbit/s rural (goal: 384 kbit/s) min. 384 kbit/s suburban (goal: 512 kbit/s) up to 2 Mbit/s urban Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 55 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 56

15 Frequencies for IMT-2000 IMT-2000 family ITU allocation (WRC 1992) MHz IMT-2000 S IMT-2000 S IS-634: define the messaging interface between TDMA, BS, and Interface for Internetworking Europe China Japan GSM 1800 GSM 1800 DE CT T D D UTRA FDD IMT-2000 cdma2000 PHS W-CDMA T S D D S S UTRA FDD S IMT-2000 S cdma2000 S W-CDMA IMT-2000 Core Network ITU-T Initial UMTS (R99 w/ FDD) GSM (MAP) ANSI-41 (IS-634) Flexible assignment of Core Network and Radio Access IP-Network North America PCS S S MHz rsv. IMT-2000 Radio Access ITU-R IMT-DS (Direct Spread) UTRA FDD (W-CDMA) 3GPP IMT-TC (Time Code) UTRA TDD (TD-CDMA); TD-SCDMA 3GPP IMT-MC (Multi Carrier) cdma2000 3GPP2 IMT-SC (Single Carrier) UWC-136 (EDGE) UWCC/3GPP IMT-FT (Freq. Time) DECT ETSI Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 57 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 58 GSM and UMTS Releases GSM and UMTS Releases (Definitions) GSM/EDGE Release 3G Release Abbreviated name Spec version number Freeze date (indicative only) Release 99 new radio access technologies Phase 2+ Release 6 Phase 2+ Release 5 Phase 2+ Release 4 - Phase 2+ Release 2000 Release 6 Release 5 Release 4 Release Rel-6 Rel-5 Rel-4 R00 6.x.y 5.x.y 4.x.y 4.x.y 9.x.y December March 2005 March - June 2002 March 2001 Renaming Release 4 introduces QoS in fixed network plus several execution environments and new service architectures - Phase 2+ Release 1999 Release R99 3.x.y 8.x.y March 2000 Release 5 radically different core (all-ip) network Phase 2+ Release R98 7.x.y early 1999 Phase 2+ Release R97 6.x.y early 1998 Release 6 Phase 2+ Release 1996 Phase 2 Phase R96 Ph2 Ph1 5.x.y 4.x.y 3.x.y early comprises the use of MIMO antennas, enhanced M, security enhancements, WLAN/UMTS interworking, broadcast/multicast services, enhanced I, IP emergency calls, and many more management features Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 59 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 60

16 Licensing Example: UMTS in Germany, 18. August 2000 UTRA-FDD: Uplink MHz Downlink MHz duplex spacing 190 MHz 12 channels, each 5 MHz UTRA-TDD: MHz, MHz; 5 MHz channels Coverage of the population 25% until 12/ % until 12/2005 Sum: billion UMTS architecture (Release 99 used here!) UTRAN (UTRA Network) handles cell level mobility Radio Network Subsystem (RNS) radio channel ciphering and deciphering, handover control, radio resource management Encapsulation of all radio specific tasks UE (User Equipment) comprises all the functions needed to access UMTS services CN (Core Network) Inter system handover gateways to other networks (fixed or wireless) Location management if there is no dedicated connection between UE and UTRAN UE U u UTRAN I u CN Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 61 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 62 USIM Domain UMTS domains and interfaces I User Equipment Domain Assigned to a single user in order to access UMTS services Infrastructure Domain C u Mobile U u Access I u Equipment Network Domain Domain User Equipment Domain Shared among all users Offers UMTS services to all accepted users Home Network Domain Serving Network Domain Z u Infrastructure Domain Y u Transit Network Domain Core Network Domain UMTS domains and interfaces II Universal Subscriber Identity Module (USIM) Functions for encryption and authentication of users Located on a SIM inserted into a mobile device Mobile Equipment Domain Functions for radio transmission User interface for establishing/maintaining end-to-end connections Access Network Domain Access network dependent functions Core Network Domain Access network independent functions Serving Network Domain Network currently responsible for communication Home Network Domain Location and access network independent functions Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 63 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 64

17 Spreading and scrambling of user data OSVF (Orthogonal Variable Spreading Factor) coding Constant chipping rate of 3.84 Mchip/s Different user data rates supported via different spreading factors higher data rate: less chips per bit and vice versa User separation via unique, quasi orthogonal scrambling codes users are not separated via orthogonal spreading codes spreading codes: separate different data streams of a sender much simpler management of codes: each station can use the same orthogonal spreading codes precise synchronisation not necessary as the scrambling codes stay quasiorthogonal data 1 data 2 data 3 data 4 data 5 spr. code 1 spr. code 2 scrambling code 1 spr. code 3 spr. code 1 scrambling code 2 sender 1 sender 2 spr. code 4 X SF=n 1,1,1,1,1,1,1,1 1,1,1,1 1,1 1,1,1,1,-1,-1,-1,-1 1,1,-1,-1,1,1,-1,-1 X,X 1,1,-1,-1 1,1,-1,-1,-1,-1,1,1 1 1,-1,1,-1,1,-1,1,-1 X,-X 1,-1,1,-1 1,-1,1,-1,-1,1,-1,1 SF=2n 1,-1 1,-1,-1,1,1,-1,-1,1 1,-1,-1,1 1,-1,-1,1,-1,1,1,-1 SF=1 SF=2 SF=4 SF= Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 65 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 66 UMTS FDD frame structure Typical UTRA-FDD uplink data rates 10 ms µs µs Radio frame Time slot Pilot TFCI FBI TPC 2560 chips, 10 bits Data 2560 chips, 10*2 k bits (k = 0...6) uplink DPCCH uplink DPDCH W-CDMA MHz uplink MHz downlink chipping rate: Mchip/s soft handover QPSK complex power control (1500 power control cycles/s) spreading: UL: 4-256; DL:4-512 User data rate [kbit/s] DPDCH [kbit/s] DPCCH [kbit/s] 12.2 (voice) µs Data 1 TPC TFCI Data 2 Pilot DPDCH DPCCH DPDCHDPCCH 2560 chips, 10*2 k bits (k = 0...7) downlink DPCH Slot structure NOT for user separation but synchronisation for periodic functions! FBI: Feedback Information TPC: Transmit Power Control TFCI: Transport Format Combination Indicator DPCCH: Dedicated Physical Control Channel DPDCH: Dedicated Physical Data Channel DPCH: Dedicated Physical Channel Spreading Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 67 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 68

18 UMTS TDD frame structure (burst type 2) UTRAN architecture 10 ms Radio frame UE 1 I ub RNS RNC: Radio Network Controller RNS: Radio Network Subsystem I u µs Data 1104 chips Time slot Midample 256 chips 2560 chips Data 1104 chips Traffic burst GP: guard period 96 chips TD-CDMA 2560 chips per slot spreading: 1-16 symmetric or asymmetric slot assignment to UL/DL (min. 1 per direction) tight synchronisation needed simpler power control ( power control cycles/s) GP midample: training and channel estimation UE 3 UE 2 I ub RNC I ur RNC CN UTRAN comprises several RNSs can support FDD or TDD or both RNC is responsible for handover decisions requiring signalingto the UE Cell offers FDD or TDD RNS Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 69 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 70 UTRAN architecture UTRAN functions UE I ub I ub RNS RNC I ur RNC RNS RNC: Radio Network Controller RNS: Radio Network Subsystem I u UTRAN comprises several RNSs can support FDD or TDD or both CN RNC is responsible for handover decisions requiring signaling to the UE Cell offers FDD or TDD Admission control Congestion control System information broadcasting Radio channel encryption Handover SRNS moving Radio network configuration Channel quality measurements Macro diversity Radio carrier control Radio resource control Data transmission over the radio interface Outer loop power control (FDD and TDD) minimize interference between neighbouring cells or control the size of a cell Channel coding Access control Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 71 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 72

19 Core network: protocols Core network: architecture VLR RNS GSM-CS backbone G PSTN/ ISDN BTS A bis BSC BSS I u VLR G PSTN HLR TSB I u CS AuC EIR HLR RNS Layer 3: IP Layer 2: ATM Layer 1: PDH, SDH, SONET SGSN GGSN GPRS backbone (IP) SS 7 PDN (X.25), Internet (IP) I ub RNC RNS I u PS SGSN G n GGSN GR G i CN UTRAN CN Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 73 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 74 Core network UMTS protocol stacks (user plane) The Core Network (CN) and thus the Interface I u, too, are separated into two logical domains: Circuit Switched Domain (CSD) Circuit switched service incl. signaling Resource reservation at connection setup GSM components (, G, VLR) I u CS Packet Switched Domain (PSD) GPRS components (SGSN, GGSN) I u PS Release 99 uses the GSM/GPRS network and adds a new radio access! Helps to save a lot of money Much faster deployment Not as flexible as newer releases (5, 6) GSM circuit switched part replaced by all-ip core Circuit switched Packet switched UE U u UTRAN I u CS 3G apps. & protocols RLC MAC radio RLC MAC radio SAR AAL2 ATM SAR AAL2 ATM UE U u UTRAN I u PS 3G G n apps. & protocols SGSN IP, PPP, IP tunnel PDCP PDCP GTP GTP GTP RLC RLC UDP/IP UDP/IP UDP/IP MAC radio MAC radio AAL5 ATM AAL5 ATM L2 L1 3G GGSN IP, PPP, GTP UDP/IP L2 L1 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 75 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 76

20 UMTS protocol stacks (user plane): Definitions Support of mobility: macro diversity AAL2 Connection-oriented, synchronous VBR traffic Packet data convergence protocol (PDCP) perform header compression to avoid redundant data transmission using scarce radio resources UE Multicasting of data via several physical channels Enables soft handover FDD mode only Uplink simultaneous reception of UE data at several s RNC CN Reconstruction of data at Node B, SRNC or DRNC Downlink Simultaneous transmission of data via different cells Different spreading codes in different cells Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 77 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 78 Support of mobility: handover Example handover types in UMTS/GSM From and to other systems (e.g., UMTS to GSM) This is a must as UMTS coverage will be poor in the beginning RNS controlling the connection is called SRNS (Serving RNS) RNS offering additional resources (e.g., for soft handover) is called Drift RNS (DRNS) End-to-end connections between UE and CN only via I u at the SRNS SRNC relocation: hard handover UE 1 UE I ub RNC 1 I ur I u 3G 1 Change of SRNS requires change of I u Initiated by the SRNS Controlled by the RNC and CN UE 3 3 RNC 2 3G 2 UE I ub SRNC I ur I u CN UE 4 BTS BSC 2G 3 A bis A DRNC I ub Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 79 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 80

21 UMTS/GSM Handover Intra-node-B, intra-rnc UE moves from one antenna of node B to another antenna softer handover: node B performs combining and splitting of data streams Inter-node-B, intra-rnc UE moves from one node B to another controlled by the same RNC RNC combines and splits data Inter-RNC UE moves from one node B to another controlled by different RNCs internal: not visible for the CN external: relocation of controlling RNC => hard handover Inter- hard handover of the connection Inter-system UE moves from a 3G UMTS network into a 2G GSM network hard handover GSM UMTS Breathing Cells Mobile device gets exclusive signal from the base station Number of devices in a cell does not influence cell size Cell size is closely correlated to the cell capacity Signal-to-nose ratio determines cell capacity Noise is generated by interference from other cells other users of the same cell Interference increases noise level Devices at the edge of a cell cannot further increase their output power (max. power limit) and thus drop out of the cell no more communication possible Limitation of the max. number of users within a cell required Cell breathing complicates network planning Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 81 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 82 Breathing Cells: Example UMTS services (originally) Data transmission service profiles Service Profile High Interactive MM High MM Medium MM Switched Data Simple Messaging Voice Bandwidth 128 kbit/s 2 Mbit/s 384 kbit/s 14.4 kbit/s 14.4 kbit/s 16 kbit/s Transport mode Circuit switched Packet switched Circuit switched Circuit switched Packet switched Circuit switched Bidirectional, video telephone Low coverage, max. 6 km/h asymmetrical, MM, downloads S successor, Virtual Home Environment (VHE) Enables access to personalized data independent of location, access network, and device Network operators may offer new services without changing the network Service providers may offer services based on components which allow the automatic adaptation to new networks and devices Integration of existing IN services Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 83 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 84

22 Example 3G Networks: Japan Example 3G networks: Australia FOMA (Freedom Of Mobile multimedia Access) in Japan Examples for FOMA phones cdma2000 1xEV-DO in Melbourne/Australia Examples for 1xEV-DO devices Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 85 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 86 Isle of Man Start of UMTS in Europe as Test UMTS in Monaco Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 87 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 88

23 UMTS in Europe Some current enhancements Vodafone/Germany Orange/UK GSM E/M E: 760 characters possible by chaining S, animated icons, ring tones, was soon replaced by M (or simply skipped) M: transmission of images, video clips, audio see WAP 2.0 / chapter 10 EDGE (Enhanced Data Rates for Global [was: GSM] Evolution) 8-PSK instead of GK, up to 384 kbit/s new modulation and coding schemes for GPRS EGPRS MCS-1 to MCS-4 uses GK at rates 8.8/11.2/14.8/17.6 kbit/s MCS-5 to MCS-9 uses 8-PSK at rates 22.4/29.6/44.8/54.4/59.2 kbit/s UMTS HSDPA (High-Speed Downlink Packet Access) initially up to 10 Mbit/s for the downlink, later on 20 Mbit/s using MIMO- (Multiple Input Multiple Output-) antennas uses 16-QAM instead of QPSK Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 89 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 90