gsm and umts - university of hong kongkcleung/courses/csis7304/summer.2006/... · gsm and umts...

of 23 /23
Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 1 GSM and UMTS Market GSM Overview Services Sub-systems Components UMTS/IMT-2000 Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 2 Mobile phone subscribers worldwide year Subscribers [million] 0 200 400 600 800 1000 1200 1400 1600 1996 1997 1998 1999 2000 2001 2002 2003 2004 approx. 1.7 bn GSM total TDMA total CDMA total PDC total Analogue total W-CDMA Total wireless Prediction (1998) Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 3 Development of mobile telecommunication systems 1G 2G 3G 2.5G IS-95 cdmaOne IS-136 TDMA D-AMPS GSM PDC GPRS IMT-DS UTRA FDD / W-CDMA EDGE IMT-TC UTRA TDD / TD-CDMA cdma2000 1X 1X EV-DV (3X) AMPS NMT IMT-SC IS-136HS UWC-136 IMT-TC TD-SCDMA CT0/1 CT2 IMT-FT DECT CDMA TDMA FDMA IMT-MC cdma2000 1X EV-DO HSDPA Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 4 How does it work? 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?

Author: phunghanh

Post on 30-Jan-2018

218 views

Category:

Documents


5 download

Embed Size (px)

TRANSCRIPT

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 1

    GSM and UMTS

    MarketGSM

    OverviewServicesSub-systemsComponents

    UMTS/IMT-2000

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 2

    Mobile phone subscribers worldwide

    year

    Subs

    crib

    ers

    [mill

    ion]

    0

    200

    400

    600

    800

    1000

    1200

    1400

    1600

    1996 1997 1998 1999 2000 2001 2002 2003 2004

    approx. 1.7 bn

    GSM total

    TDMA total

    CDMA total

    PDC total

    Analogue total

    W-CDMA

    Total wireless

    Prediction (1998)

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 3

    Development of mobile telecommunication systems

    1G 2G 3G2.5G

    IS-95cdmaOne

    IS-136TDMAD-AMPSGSMPDC

    GPRS

    IMT-DSUTRA FDD / W-CDMA

    EDGE

    IMT-TCUTRA TDD / TD-CDMA

    cdma2000 1X

    1X EV-DV(3X)

    AMPSNMT

    IMT-SCIS-136HSUWC-136

    IMT-TCTD-SCDMA

    CT0/1

    CT2IMT-FTDECT

    CD

    MA

    TDM

    AFD

    MA

    IMT-MCcdma2000 1X EV-DO

    HSDPA

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 4

    How does it work?

    How can the system locate a user?Why dont all phones ring at the same time?What happens if two users talk simultaneously?Why dont I get the bill from my neighbor?Why can an Australian use her phone in Berlin?

    Why cant I simply overhear the neighbors 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 5

    GSM: Overview

    GSMformerly: Groupe Spciale Mobile (founded 1982)now: Global System for Mobile CommunicationPan-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 possibletoday 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 networksmore than 75% of all digital mobile phones use GSM (74% total)over 200 million SMS per month in Germany, > 550 billion/year worldwide(> 10% of the revenues for many operators)[be aware: these are only rough numbers]

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 6

    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 connectivityone number, the network handles localization

    High capacity better frequency efficiency, smaller cells, more customers per cell

    High transmission qualityhigh 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 7

    Disadvantages of GSM

    There is no perfect system!!no end-to-end encryption of user datano 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 drivingelectromagnetic radiation

    abuse of private data possibleroaming profiles accessible

    high complexity of the systemseveral incompatibilities within the GSM standards

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 8

    GSM: Mobile Services

    GSM offersseveral types of connections

    voice connections, data connections, short message servicemulti-service options (combination of basic services)

    Three service domainsBearer ServicesTelematic ServicesSupplementary Services

    Enhancements for standard telephony service

    GSM-PLMNtransit

    network(PSTN, ISDN)

    source/destination

    networkTE TE

    bearer services

    tele services

    R, S (U, S, R)UmMT

    MS

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 9

    Bearer Services

    Telecommunication services to transfer data between access pointsSpecification 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/sasynchronous: 300 - 1200 bit/s

    data service (packet switched)synchronous: 2.4, 4.8 or 9.6 kbit/sasynchronous: 300 - 9600 bit/s

    transparent bearer servicesdo not try to recover lost data

    non-transparent bearer servicesuse 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!

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 10

    Tele Services I

    Telecommunication services that enable voice communication via mobile phonesAll 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 servicesmobile telephonyprimary goal of GSM was to enable mobile telephony offering the traditional bandwidth of 3.1 kHz Emergency numbercommon number throughout Europe (112); mandatory for all service providers; free of charge; connection with the highest priority (preemption of other connections possible)Multinumberingseveral ISDN phone numbers per user possible

    according to the desired service

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 11

    Tele Services II

    Additional servicesNon-Voice-Teleservices

    group 3 faxvoice mailbox (implemented in the fixed network supporting the mobile terminals)electronic mail (MHS, Message Handling System, implemented in the fixed network)...

    Short Message Service (SMS)alphanumeric data transmission to/from the mobile terminal (160 characters) using the signaling channel, thus allowing simultaneous use of basic services and SMS(almost ignored in the beginning now the most successful add-on!)

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 12

    Supplementary services

    Services in addition to the basic services, cannot be offered stand-aloneSimilar to ISDN services besides lower bandwidth due to the radio linkMay differ between different service providers, countries and protocol versions Important services

    identification: forwarding of caller numbersuppression of number forwardingautomatic call-back: keep trying the number until getting throughconferencing with up to 7 participantslocking of the mobile terminal (incoming or outgoing calls)...

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 13

    Architecture of the GSM system (GSM-PLMN)

    GSM is a PLMN (Public Land Mobile Network)several providers setup mobile networks following the GSM standard within each countrycomponents

    MS (mobile station)BS (base station)MSC (mobile switching center)LR (location register)

    subsystemsRSS (radio subsystem): covers all radio aspectsNSS (network and switching subsystem): call forwarding, handover, switchingOSS (operation subsystem): management of the network

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 14

    Ingredients 1: Mobile Phones, PDAs & Co.

    The visible but smallestpart of the network!

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 15

    Ingredients 2: Antennas

    Still visible cause many discussions

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 16

    Ingredients 3: Infrastructure 1

    Base Stations

    Cabling

    Microwave links

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 17

    Ingredients 3: Infrastructure 2

    Switching units

    Data bases

    Management

    Monitoring

    Not visible, butcomprise the major partof the network (also from an investmentpoint of view)

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 18

    GSM: overview

    fixed network

    BSC

    BSC

    MSC MSC

    GMSC

    OMC, EIR, AUC

    VLR

    HLRNSSwith OSS

    RSS

    VLR

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 19

    GSM: elements and interfaces

    NSS

    MS MS

    BTS

    BSC

    GMSC

    IWF

    OMC

    BTS

    BSC

    MSC MSC

    Abis

    Um

    EIR

    HLR

    VLR VLR

    A

    BSS

    PDN

    ISDN, PSTN

    RSS

    radio cell

    radio cell

    MS

    AUCOSS

    signaling

    O

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 20

    Um

    Abis

    ABSS

    radiosubsystem

    MS MS

    BTSBSC

    BTS

    BTSBSC

    BTS

    network and switching subsystem

    MSC

    MSC

    fixedpartner networks

    IWF

    ISDNPSTN

    PSPDNCSPDN

    SS

    7

    EIR

    HLR

    VLR

    ISDNPSTN

    GSM: system architecture

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 21

    System architecture: radio subsystem

    ComponentsMS (Mobile Station)BSS (Base Station Subsystem):consisting of

    BTS (Base Transceiver Station):sender and receiverBSC (Base Station Controller):controlling several transceivers

    InterfacesUm : radio interfaceAbis : standardized, open interface with 16/64 kbit/s user channelsA: standardized, open interface with 64 kbit/s user channels

    UmAbis

    A

    BSS

    radiosubsystem

    network and switchingsubsystem

    MS MS

    BTSBSC MSC

    BTS

    BTSBSC

    BTSMSC

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 22

    System architecture: network and switching subsystem

    ComponentsMSC (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.)

    DatabasesHLR (Home Location Register)VLR (Visitor Location Register)EIR (Equipment Identity Register)

    networksubsystem

    MSC

    MSC

    fixed partnernetworks

    IWF

    ISDNPSTN

    PSPDNCSPDN

    SS

    7

    EIR

    HLR

    VLR

    ISDNPSTN

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 23

    Radio subsystem

    The Radio Subsystem (RSS) comprises the cellular mobile network up to the switching centersComponents

    Base Station Subsystem (BSS):Base Transceiver Station (BTS): radio components including sender, receiver, antenna - if directed antennas are used one BTS can cover several cellsBase Station Controller (BSC): switching between BTSs, controlling BTSs, managing of network resources, mapping of radio channels (Um) onto terrestrial channels (A interface)

    BSS = BSC + sum(BTS) + interconnection

    Mobile Stations (MS)

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 24

    possible radio coverage of the cell

    idealized shape of the cellcell

    segmentation of the area into cells

    GSM: cellular network

    use of several carrier frequenciesnot the same frequency in adjoining cellscell 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 25

    GSM frequency bands

    921-960921-925

    876-915876-880

    955-1024, 0-12469 channels

    GSM-Rexclusive

    1930-19901850-1910512-810GSM 1900 (Americas)

    1805-18801710-1785512-885GSM 1800

    921-960935-960925-960

    876-915890-915880-915

    0-124, 955-1023124 channels+49 channels

    GSM 900classicalextended

    869-894824-849128-251GSM 850 (Americas)

    Downlink [MHz]Uplink [MHz]ChannelsType

    - Additionally: GSM 400 (also named GSM 450 or GSM 480 at 450-458/460-468 or 479-486/489-496 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 26

    Example coverage of GSM networks (www.gsmworld.com)

    T-Mobile (GSM-900/1800) Germany O2 (GSM-1800) Germany

    AT&T (GSM-850/1900) USA Vodacom (GSM-900) South Africa

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 27

    Base Transceiver Station and Base Station Controller

    Tasks of a BSS are distributed over BSC and BTSBTS comprises radio specific functionsBSC is the switching center for radio channels

    Functions BTS BSCManagement of radio channels XFrequency hopping (FH) X XManagement of terrestrial channels XMapping of terrestrial onto radio channels XChannel coding and decoding XRate adaptation XEncryption and decryption X XPaging X XUplink signal measurements XTraffic measurement XAuthentication XLocation registry, location update XHandover management X

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 28

    Mobile station

    Terminal for the use of GSM servicesA mobile station (MS) comprises several functional groups

    MT (Mobile Terminal):offers common functions used by all services the MS offerscorresponds to the network termination (NT) of an ISDN accessend-point of the radio interface (Um)

    TA (Terminal Adapter):terminal adaptation, hides radio specific characteristics

    TE (Terminal Equipment):peripheral device of the MS, offers services to a userdoes not contain GSM specific functions

    SIM (Subscriber Identity Module):personalization of the mobile terminal, stores user parameters

    R S UmTE TA MT

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 29

    Network and switching subsystem

    NSS is the main component of the public mobile network GSMswitching, mobility management, interconnection to other networks, system control

    mobility management: handovers between different BSSs

    ComponentsMobile Services Switching Center (MSC)controls all connections via a separated network to/from a mobile terminal within the domain of the MSC - several BSC can belong to a MSCDatabases (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

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 30

    Mobile Services Switching Center

    The MSC (mobile switching center) plays a central role in GSMswitching functionsadditional functions for mobility supportmanagement of network resourcesinterworking functions via Gateway MSC (GMSC)integration of several databases

    Functions of a MSCspecific functions for paging and call forwardingtermination of SS7 (signaling system no. 7)

    SS7: handles all signalling needed for connection setup, connection release and handover of connections to other MSCs

    mobility specific signalinglocation registration and forwarding of location informationprovision of new services (fax, data calls)support of short message service (SMS)generation and forwarding of accounting and billing information

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 31

    Operation subsystem

    The OSS (Operation Subsystem) enables network operation, management, and maintenance of all GSM subsystemsComponents

    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 rightsstolen 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 subsystemtraffic 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 32

    1 2 3 4 5 6 7 8

    higher GSM frame structures

    935-960 MHz124 channels (200 kHz)downlink

    890-915 MHz124 channels (200 kHz)uplink

    frequ

    ency

    time

    GSM TDMA frame

    GSM time-slot (normal burst)

    4.615 ms

    546.5 s577 s

    tail user data TrainingSguardspace S user data tail

    guardspace

    3 bits 57 bits 26 bits 57 bits1 1 3

    GSM - TDMA/FDMA

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 33

    GSM TDMA/FDMA (Definitions)

    Normal burstdata transmission

    Tailset to 0used to enhance the receiver performance

    Training sequenceadapt the parameters of the receiver to the current path propagation characteristicsselect the strongest signal in case of multi-path propagation

    Flag Sindicate whether the data field contains user or network control data

    Guard spaceavoid overlapping with other bursts due to different path delaysgive the transmitter time to turn on and off

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 34

    GSM hierarchy of frames

    0 1 2 2045 2046 2047...hyperframe: count each TDMA frame as input for encryption algorithm

    0 1 2 48 49 50...

    0 1 24 25...

    superframe

    0 1 24 25...

    0 1 2 48 49 50...

    0 1 6 7...

    multiframe

    frame

    burstslot

    577 s

    4.615 ms

    120 ms (traffic)

    235.4 ms (control)

    6.12 s

    3 h 28 min 53.76 s

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 35

    GSM protocol layers for signaling

    CM

    MM

    RR

    MM

    LAPDm

    radio

    LAPDm

    radio

    LAPD

    PCM

    RR BTSM

    CM

    LAPD

    PCM

    RRBTSM

    16/64 kbit/s

    Um Abis A

    SS7

    PCM

    SS7

    PCM

    64 kbit/s /2.048 Mbit/s

    MS BTS BSC MSC

    BSSAP BSSAP

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 36

    GSM protocol layers for signaling (Definitions)

    Layer 1handles all radio-specific functions

    LAPDmoffers reliable data transfer over connectionsre-sequencing of data framesflow control

    LAPD: LAPDm + synchronization and checksumming for error detectionRadio resource management (RR)

    setup, maintenance, and release of radio channelsMobility management (MM)

    functions for registration, authentication, identification, location updating, and the provision of a temporary mobile subscriber identity (TMSI)

    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 MSC

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 37

    Mobile Terminated Call

    PSTNcallingstation GMSC

    HLR VLR

    BSSBSSBSS

    MSC

    MS

    1 2

    3

    45

    6

    7

    8 9

    10

    11 12

    1316

    10 10

    11 11 11

    14 15

    17

    1: calling a GSM subscriber2: forwarding call to GMSC3: signal call setup to HLR4, 5: request MSRN from VLR6: forward responsible

    MSC to GMSC7: forward call to

    current MSC8, 9: get current (availability) status of MS10, 11: paging of MS12, 13: MS answers14, 15: security checks16, 17: set up connection

    MSRN: mobile station roaming number

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 38

    Mobile Originated Call

    PSTN GMSC

    VLR

    BSS

    MSC

    MS1

    2

    6 53 4

    9

    10

    7 8

    1, 2: connection request3, 4: security check5-8: check resources (free circuit)9-10: set up call

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 39

    MTC/MOC

    BTSMS

    paging request

    channel request

    immediate assignment

    paging response

    authentication request

    authentication response

    ciphering command

    ciphering complete

    setup

    call confirmed

    assignment command

    assignment complete

    alerting

    connect

    connect acknowledge

    data/speech exchange

    BTSMS

    channel request

    immediate assignment

    service request

    authentication request

    authentication response

    ciphering command

    ciphering complete

    setup

    call confirmed

    assignment command

    assignment complete

    alerting

    connect

    connect acknowledge

    data/speech exchange

    MTC MOC

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 40

    4 types of handover

    MSC MSC

    BSC BSCBSC

    BTS BTS BTSBTS

    MS MS MS MS

    12 3 4

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 41

    GSM Handover

    Intra-cell handoverchange the carrier frequency

    Inter-cell, intra-BSC handoverassign a new radio channel in the new cell and release the old one

    Inter-BSC, intra-MSC handoverperform handovers between cells controlled by different BSCs

    Inter-MSC handoverhandover between two cells belonging to different MSCs

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 42

    Handover decision

    receive levelBTSold

    receive levelBTSold

    MS MS

    HO_MARGIN

    BTSold BTSnew

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 43

    Handover procedure

    HO access

    BTSold BSCnewmeasurementresult

    BSCold

    Link establishment

    MSCMSmeasurementreport

    HO decisionHO required

    BTSnew

    HO request

    resource allocationch. activation

    ch. activation ackHO request ackHO commandHO commandHO command

    HO completeHO completeclear commandclear command

    clear complete clear complete

    HO complete

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 44

    Security in GSM

    Security servicesaccess control/authentication

    user SIM (Subscriber Identity Module): secret PIN (personal identification number)SIM network: challenge response method

    challenge: random number; response: signed response (SRES)

    confidentialityvoice and signaling encrypted on the wireless link (after successful authentication)

    anonymitytemporary identity TMSI (Temporary Mobile Subscriber Identity)newly assigned at each new location update (LUP)encrypted transmission

    3 algorithms specified in GSMA3 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 45

    GSM - authentication

    A3

    RANDKi

    128 bit 128 bit

    SRES* 32 bit

    A3

    RAND Ki

    128 bit 128 bit

    SRES 32 bit

    SRES* =? SRES SRES

    RAND

    SRES32 bit

    mobile network SIM

    AC

    MSC

    SIM

    Ki: individual subscriber authentication key SRES: signed response

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 46

    GSM - key generation and encryption

    A8

    RANDKi

    128 bit 128 bit

    Kc64 bit

    A8

    RAND Ki

    128 bit 128 bit

    SRES

    RAND

    encrypteddata

    mobile network (BTS) MS with SIM

    AC

    BSS(BTS / BSC)

    SIM

    A5

    Kc64 bit

    A5MS

    data data

    cipherkey

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 47

    Data services in GSM I

    Data transmission standardized with only 9.6 kbit/sadvanced coding allows 14,4 kbit/snot enough for Internet and multimedia applications

    HSCSD (High-Speed Circuit Switched Data)mainly software update (upgrades in MS and MSC)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, simpledisadvantage: channels blocked for voice transmission

    still use the connection-oriented mechanisms of GSMAIUR [kbit/s] TCH/F4.8 TCH/F9.6 TCH/F14.4

    4.8 19.6 2 1

    14.4 3 119.2 4 228.8 3 238.4 443.2 357.6 4

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 48

    Data services in GSM II

    GPRS (General Packet Radio Service)packet switchingusing free slots only if data packets ready to send (e.g., 50 kbit/s using 4 slots temporarily)standardization 1998, introduction 2001advantage: one step towards UMTS, more flexibledisadvantage: more investment needed (new hardware)

    GPRS network elementsGSN (GPRS Support Nodes): GGSN and SGSNGGSN (Gateway GSN)

    interworking unit between GPRS and PDN (Packet Data Network)SGSN (Serving GSN)

    supports the MS (location, billing, security)GR (GPRS Register)

    user addressesmapping between a mobiles identity and the PSPDN address

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 49

    GPRS quality of service

    Reliabilityclass

    Lost SDUprobability

    DuplicateSDU

    probability

    Out ofsequence

    SDUprobability

    Corrupt SDUprobability

    1 10-9 10-9 10-9 10-9

    2 10-4 10-5 10-5 10-63 10-2 10-5 10-5 10-2

    Delay SDU size 128 byte SDU size 1024 byteclass mean 95 percentile mean 95 percentile

    1 < 0.5 s < 1.5 s < 2 s < 7 s2 < 5 s < 25 s < 15 s < 75 s3 < 50 s < 250 s < 75 s < 375 s4 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 50

    Examples for GPRS device classes

    54412

    52410

    5148

    4225

    3223

    3122

    2111

    Maximum number of slotsSending slotsReceiving slotsClass

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 51

    GPRS user data rates in kbit/s

    171.2149.8128.410785.664.242.821.4CS-4

    124.8109.293.67862.446.831.215.6CS-3

    107.293.880.46753.640.226.813.4CS-2

    72.463.3554.345.2536.227.1518.19.05CS-1

    8 slots7 slots6 slots5 slots4 slots3 slots2 slots1 slotCoding scheme

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 52

    GPRS architecture and interfaces

    MS BSS GGSNSGSN

    MSC

    Um

    EIR

    HLR/GR

    VLR

    PDN

    Gb Gn Gi

    SGSN

    Gn

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 53

    GPRS protocol architecture

    apps.

    IP/X.25

    LLC

    GTP

    MAC

    radio

    MAC

    radioFR

    RLC BSSGP

    IP/X.25

    FR

    Um Gb Gn

    L1/L2 L1/L2

    MS BSS SGSN GGSN

    UDP/TCP

    Gi

    SNDCP

    RLC BSSGP IP IP

    LLC UDP/TCPSNDCP GTP

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 54

    GPRS protocol architecture (Definitions)

    Base station subsystem GPRS protocol (BSSGP)Convey routing and QoS-related information between BSS and SGSN

    Subnetwork dependent convergence protocol (SNDCP)adapt to different characteristics of the underlying networks between SGSN and MStransport between GSNs within the GPRS backbone

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 55

    Original Goals for 3G

    Establish a common worldwide communication systemallowed for terminal and user mobility

    Support the idea of universal personal telecommunication

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 56

    UMTS and IMT-2000

    Proposals for IMT-2000 (International Mobile Telecommunications)UWC-136, cdma2000, WP-CDMAUMTS (Universal Mobile Telecommunications System) from ETSI

    UMTSUTRA (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

    requirementsmin. 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 57

    Frequencies for IMT-2000

    IMT-2000

    1850 1900 1950 2000 2050 2100 2150 2200 MHz

    MSS

    ITU allocation(WRC 1992) IMT-2000

    MSS

    Europe

    China

    Japan

    NorthAmerica

    UTRAFDD

    UTRAFDD

    TDD

    TDD

    MSS

    MSS

    DECT

    GSM1800

    1850 1900 1950 2000 2050 2100 2150 2200 MHz

    IMT-2000 MSS IMT-2000MSS

    GSM1800

    cdma2000W-CDMA

    MSS

    MSS

    MSS

    MSS

    cdma2000W-CDMAPHS

    PCS rsv.

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 58

    IMT-2000 family

    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

    GSM(MAP)

    ANSI-41(IS-634) IP-Network

    IMT-2000Core NetworkITU-T

    IMT-2000Radio AccessITU-R

    Interface for Internetworking

    Flexible assignment of Core Network and Radio Access

    Initial UMTS(R99 w/ FDD)

    IS-634: define the messaging interface between TDMA, BS, and MSC

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 59

    GSM and UMTS Releases

    19923.x.yPh1-Phase 1

    19954.x.yPh2-Phase 2

    early 19975.x.yR96-Phase 2+ Release 1996

    early 19986.x.yR97-Phase 2+ Release 1997

    early 19997.x.yR98-Phase 2+ Release 1998

    8.x.y-Phase 2+ Release 1999March 2000

    3.x.yR99

    Release 1999-

    9.x.y-Phase 2+ Release 2000Renaming

    4.x.yR00

    Release 2000-

    March 20014.x.yRel-4Release 4Phase 2+ Release 4

    March - June 20025.x.yRel-5Release 5Phase 2+ Release 5

    December 2004 -March 20056.x.yRel-6Release 6Phase 2+ Release 6

    Freeze date(indicative only)

    Spec versionnumberAbbreviated name3G ReleaseGSM/EDGE Release

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 60

    GSM and UMTS Releases (Definitions)

    Release 99new radio access technologies

    Release 4introduces QoS in fixed network plus several execution environments and new service architectures

    Release 5radically different core (all-IP) network

    Release 6comprises the use of MIMO antennas, enhanced MMS, security enhancements, WLAN/UMTS interworking, broadcast/multicast services, enhanced IMS, IP emergency calls, and many more management features

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 61

    Licensing Example: UMTS in Germany, 18. August 2000

    Sum: 50.81 billion

    UTRA-FDD: Uplink 1920-1980 MHzDownlink 2110-2170 MHzduplex spacing 190 MHz 12 channels, each 5 MHz

    UTRA-TDD: 1900-1920 MHz, 2010-2025 MHz; 5 MHz channels

    Coverage of the population 25% until 12/200350% until 12/2005

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 62

    UMTS architecture (Release 99 used here!)

    UTRANUE CN

    IuUu

    UTRAN (UTRA Network)handles cell level mobilityRadio Network Subsystem (RNS)

    radio channel ciphering and deciphering, handover control, radio resource management

    Encapsulation of all radio specific tasksUE (User Equipment)

    comprises all the functions needed to access UMTS servicesCN (Core Network)

    Inter system handovergateways to other networks (fixed or wireless)

    Location management if there is no dedicated connection between UE and UTRAN

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 63

    UMTS domains and interfaces I

    User Equipment DomainAssigned to a single user in order to access UMTS services

    Infrastructure DomainShared among all usersOffers UMTS services to all accepted users

    USIMDomain

    MobileEquipment

    Domain

    AccessNetworkDomain

    ServingNetworkDomain

    TransitNetworkDomain

    HomeNetworkDomain

    Cu Uu Iu

    User Equipment Domain

    ZuYu

    Core Network Domain

    Infrastructure Domain

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 64

    UMTS domains and interfaces II

    Universal Subscriber Identity Module (USIM)Functions for encryption and authentication of usersLocated on a SIM inserted into a mobile device

    Mobile Equipment DomainFunctions for radio transmission User interface for establishing/maintaining end-to-end connections

    Access Network DomainAccess network dependent functions

    Core Network DomainAccess network independent functionsServing Network Domain

    Network currently responsible for communicationHome Network Domain

    Location and access network independent functions

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 65

    Spreading and scrambling of user dataConstant chipping rate of 3.84 Mchip/sDifferent user data rates supported via different spreading factors

    higher data rate: less chips per bit and vice versaUser separation via unique, quasi orthogonal scrambling codes

    users are not separated via orthogonal spreading codesspreading codes: separate different data streams of a sender

    much simpler management of codes: each station can use the same orthogonal spreading codesprecise synchronisation not necessary as the scrambling codes stay quasi-orthogonal

    data1 data2 data3

    scramblingcode1

    spr.code3

    spr.code2

    spr.code1

    data4 data5

    scramblingcode2

    spr.code4

    spr.code1

    sender1 sender2

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 66

    OSVF (Orthogonal Variable Spreading Factor) coding

    1

    1,1

    1,-1

    1,1,1,1

    1,1,-1,-1

    X

    X,X

    X,-X 1,-1,1,-1

    1,-1,-1,11,-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,-1,1

    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,-1,-1,-1

    SF=1 SF=2 SF=4 SF=8

    SF=n SF=2n

    ...

    ...

    ...

    ...

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 67

    UMTS FDD frame structure

    W-CDMA 1920-1980 MHz uplink 2110-2170 MHz downlink chipping rate:

    3.840 Mchip/s soft handover QPSK complex power control

    (1500 power control cycles/s)

    spreading: UL: 4-256; DL:4-512

    0 1 2 12 13 14...

    Radio frame

    Pilot FBI TPC

    Time slot

    666.7 s

    10 ms

    Data

    Data1

    uplink DPDCH

    uplink DPCCH

    downlink DPCHTPC TFCI Pilot

    666.7 s

    666.7 s

    DPCCH DPDCH

    2560 chips, 10 bits

    2560 chips, 10*2k bits (k = 0...6)

    TFCI

    2560 chips, 10*2k bits (k = 0...7)

    Data2

    DPDCH DPCCHFBI: Feedback InformationTPC: Transmit Power ControlTFCI: Transport Format Combination IndicatorDPCCH: Dedicated Physical Control ChannelDPDCH: Dedicated Physical Data ChannelDPCH: Dedicated Physical ChannelSlot structure NOT for user separation

    but synchronisation for periodic functions!

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 68

    Typical UTRA-FDD uplink data rates

    481664Spreading

    15151515DPCCH [kbit/s]

    96048024060DPDCH [kbit/s]

    3841446412.2 (voice)User data rate [kbit/s]

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 69

    UMTS TDD frame structure (burst type 2)

    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 (100-800 power control cycles/s)

    0 1 2 12 13 14...

    Radio frame

    Data1104 chips

    Midample256 chips

    Data1104 chips

    Time slot

    666.7 s

    10 ms

    Traffic burstGP

    midample: training and channel estimation

    GP: guard period96 chips

    2560 chips

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 70

    UTRAN architecture

    UTRAN comprises severalRNSs

    Node B can support FDD orTDD or both

    RNC is responsible for handoverdecisions requiringsignalingto the UE

    Cell offers FDD or TDD

    RNC: Radio Network ControllerRNS: Radio Network Subsystem

    Node B

    Node B

    RNC

    Iub

    Node B

    UE1

    RNS

    CN

    Node B

    Node B

    RNC

    Iub

    Node B

    RNS

    Iur

    Node B

    UE2

    UE3

    Iu

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 71

    UTRAN architecture

    RNC

    Iub

    RNS

    CN

    RNC

    Iub

    RNS

    Iur

    Iu

    Node B

    Node BNode B

    Node BNode B

    Node B

    Node B

    UTRAN comprises several RNSsNode B can support FDD or TDD

    or both

    RNC is responsible for handoverdecisions requiring signalingto the UE

    Cell offers FDD or TDD

    RNC: Radio Network ControllerRNS: Radio Network SubsystemUE

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 72

    UTRAN functions

    Admission controlCongestion controlSystem information broadcastingRadio channel encryptionHandoverSRNS movingRadio network configurationChannel quality measurementsMacro diversityRadio carrier controlRadio resource controlData transmission over the radio interfaceOuter loop power control (FDD and TDD)

    minimize interference between neighbouring cells or control the size of a cellChannel codingAccess control

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 73

    Core network: protocols

    MSC

    RNS

    SGSN GGSN

    GMSC

    HLR

    VLR

    RNS

    Layer 1: PDH, SDH, SONET

    Layer 2: ATM

    Layer 3: IPGPRS backbone (IP)

    SS 7

    GSM-CSbackbone

    PSTN/ISDN

    PDN (X.25),Internet (IP)

    UTRAN CN

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 74

    Core network: architecture

    BTS

    Node B

    BSC

    Abis

    BTS

    BSS

    MSC

    Node B

    Node B

    RNC

    Iub

    Node BRNS

    Node BSGSN GGSN

    GMSC

    HLR

    VLR

    IuPS

    IuCS

    Iu

    CN

    EIR

    Gn Gi

    PSTN

    AuC

    GR

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 75

    Core network

    The Core Network (CN) and thus the Interface Iu, too, are separated into two logical domains:Circuit Switched Domain (CSD)

    Circuit switched service incl. signalingResource reservation at connection setupGSM components (MSC, GMSC, VLR)IuCS

    Packet Switched Domain (PSD)GPRS components (SGSN, GGSN)IuPS

    Release 99 uses the GSM/GPRS network and adds a new radio access!Helps to save a lot of money Much faster deploymentNot as flexible as newer releases (5, 6)

    GSM circuit switched part replaced by all-IP core

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 76

    UMTS protocol stacks (user plane)

    apps. &protocols

    MAC

    radio

    MAC

    radio

    RLC SAR

    Uu IuCSUE UTRAN 3GMSC

    RLC

    AAL2

    ATM

    AAL2

    ATM

    SAR

    apps. &protocols

    MACradio

    MACradio

    PDCP GTP

    Uu IuPSUE UTRAN 3GSGSN

    RLCAAL5ATM

    AAL5ATM

    UDP/IPPDCP

    RLC UDP/IP UDP/IP

    Gn

    GTP GTP

    L2L1

    UDP/IPL2L1

    GTP

    3GGGSN

    IP, PPP,

    IP, PPP,

    IP tunnel

    Circuitswitched

    Packetswitched

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 77

    UMTS protocol stacks (user plane): Definitions

    AAL2Connection-oriented, synchronous VBR traffic

    Packet data convergence protocol (PDCP)perform header compression to avoid redundant data transmission using scarce radio resources

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 78

    Support of mobility: macro diversity

    Multicasting of data via several physical channels

    Enables soft handoverFDD mode only

    Uplinksimultaneous reception of UE data at several Node BsReconstruction of data at Node B, SRNC or DRNC

    DownlinkSimultaneous transmission of data via different cellsDifferent spreading codes in different cells

    CNNode B RNC

    Node BUE

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 79

    Support of mobility: handover

    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 Iu at the SRNS

    SRNC relocation: hard handoverChange of SRNS requires change of IuInitiated by the SRNSControlled by the RNC and CN

    SRNC

    UE

    DRNC

    Iur

    CN

    IuNode B

    Iub

    Node BIub

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 80

    Example handover types in UMTS/GSM

    RNC1

    UE1

    RNC2

    Iur

    3G MSC1Iu

    Node B1

    IubNode B2

    Node B3 3G MSC2

    BSCBTS 2G MSC3AAbis

    UE2

    UE3

    UE4

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 81

    UMTS/GSM Handover

    Intra-node-B, intra-RNCUE moves from one antenna of node B to another antennasofter handover: node B performs combining and splitting of data streams

    Inter-node-B, intra-RNCUE moves from one node B to another controlled by the same RNCRNC combines and splits data

    Inter-RNCUE moves from one node B to another controlled by different RNCsinternal: not visible for the CNexternal: relocation of controlling RNC => hard handover

    Inter-MSChard handover of the connection

    Inter-systemUE moves from a 3G UMTS network into a 2G GSM networkhard handover

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 82

    Breathing Cells

    GSMMobile device gets exclusive signal from the base station Number of devices in a cell does not influence cell size

    UMTSCell size is closely correlated to the cell capacitySignal-to-nose ratio determines cell capacityNoise is generated by interference from

    other cellsother users of the same cell

    Interference increases noise levelDevices 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 possibleLimitation 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 83

    Breathing Cells: Example

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 84

    UMTS services (originally)

    Data transmission service profiles

    Virtual Home Environment (VHE)Enables access to personalized data independent of location, access network, and deviceNetwork operators may offer new services without changing the networkService providers may offer services based on components which allow the automatic adaptation to new networks and devicesIntegration of existing IN services

    Circuit switched16 kbit/sVoiceSMS successor, E-MailPacket switched14.4 kbit/sSimple Messaging

    Circuit switched14.4 kbit/sSwitched Dataasymmetrical, MM, downloadsCircuit switched384 kbit/sMedium MMLow coverage, max. 6 km/hPacket switched2 Mbit/sHigh MMBidirectional, video telephoneCircuit switched128 kbit/sHigh Interactive MM

    Transport modeBandwidthService Profile

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 85

    Example 3G Networks: Japan

    FOMA (Freedom Of Mobile multimediaAccess) in Japan

    Examples for FOMA phones

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 86

    Example 3G networks: Australia

    cdma2000 1xEV-DO in Melbourne/Australia

    Examples for 1xEV-DO devices

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 87

    Isle of Man Start of UMTS in Europe as Test

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 88

    UMTS in Monaco

  • Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 89

    UMTS in Europe

    Vodafone/Germany

    Orange/UK

    Dr. Ka-Cheong Leung CSIS 7304 The Wireless Internet and Mobile Computing 90

    Some current enhancements

    GSMEMS/MMS

    EMS: 760 characters possible by chaining SMS, animated icons, ring tones, was soon replaced by MMS (or simply skipped)MMS: 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 GMSK, up to 384 kbit/snew modulation and coding schemes for GPRS EGPRS

    MCS-1 to MCS-4 uses GMSK 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

    UMTSHSDPA (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-) antennasuses 16-QAM instead of QPSK