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Evolution From GSM to UMTS

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    Evolution From GSM to UMTS

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    Evolution From GSM to UMTS

    Steps on the way to 3G

    HSCSD

    GPRS

    EDGE

    UMTS

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    HSCSD(High Speed Circuit Switched Data)

    Introduction

    Next step of GSM data development

    High speed access to data services

    Circuit switched connection

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    HSCSD(High Speed Circuit Switched Data)

    HSCSD technology New channel coding scheme

    (increase the data rate to 14.4 kbps)

    Possibility of combining time slots

    (variety of bit rates from 14.4 to 57.6 kbps)

    Using different data rates in the uplink andthe downlink direction

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    HSCSD(High Speed Circuit Switched Data)

    Symmetrical connection(2+2)

    2 time slots for the uplink

    2 time slots for the downlink

    Asymmetrical connection

    (3+1)

    1 time slots for the uplink

    3 time slots for the downlink

    Example: downloading a

    web page

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    HSCSD(High Speed Circuit Switched Data)

    Type of connection speeds

    Normal connection speed Max connection speed

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    HSCSD(High Speed Circuit Switched Data)

    Applications requiring HSCSD1. Transparent applications (fax ,video)

    2. Non transparent applications (www ,email)

    Examples1. Email sending and receiving

    2. www browsing

    3. File transfer4. Real times applications

    5. Time critical wireless imaging

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    HSCSD(High Speed Circuit Switched Data)

    Disadvantage ofHSCSD

    Limited number ofuser

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    GPRS(General Packet Radio Service)

    Introduction

    Permits packet switched besides circuit switched

    It is an expansion of GSM and a main step towards 3G Charging is no longer based on the transmission time

    Data rate depends on the coding scheme (CS1 CS4)

    with a max theoretical data rate 171.2 kbps

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    GPRS(General Packet Radio Service)

    How to upgrade a GSM network to GPRS?

    1. For the BSS software upgrade

    hardware upgrade

    (PCU)

    2. New GPRS support nodes (SGSN GGSN)

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    GSMNetwork

    PSTN

    BSC

    GSM

    BTS

    GSMBTS

    MSC

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    PSTN

    BSC

    GSMBTS

    GSMBTS

    MSC

    GSM + GPRSNetwork

    PCU

    Other nets

    GGSN

    SGSN

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    Node B Node B

    RNC

    PSTN

    BSC

    GSMBTS

    GSMBTS

    PCU

    Other nets

    GGSN

    SGSN

    GSM & UMTSNetwork

    GGSN

    SGSNMSCu u

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    GPRS Coding Schemes

    GPRS using samephysical RF layer asGSM speech

    Data is coded intonormal bursts (456bits / 20ms)

    Coding

    Scheme

    Coded

    bits

    Data

    Rate(kbps)

    Multiple

    SlotMax.

    Data

    Rate

    (kbps)

    CS-1 456 9.05 72.4

    CS-2 588 13.4 107.2

    CS-3 676 15.6 124.8

    CS-4 456 21.4 171.2Max. Per TS Data rate (kbps)

    0

    5

    10

    15

    20

    25

    CS-1 CS-2 CS-3 CS-4

    KBitsperSecond

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    GPRS Coding Schemes

    Coding Scheme User Data Rate / TS Error correction Max throughputwith 8TS

    CS-1 9.05 Kbps High 72.4 Kbps

    CS-2 13.4 Kbps Medium 107.2 Kbps

    CS-3 15.6 Kbps Low 124.8 Kbps

    CS-4 21.4 Kbps None 171.2 Kbps

    Higher data rate for increased throughput

    Benefits

    Improved user perception

    Potential for new revenue streams (new applications / higher grade of service)

    Opportunity for market differentiation

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    Timeslot sharing

    BTS

    BCCH GPRS GPRS GPRSTCHTCH TCH User rate at

    CS2 = 40.2 kbps

    TCH

    A Voice call require the GPRS TS

    Site with one carrier will be able to share time slots (Voice and GPRS)

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    Timeslot sharing

    BTS

    BCCH GPRS GPRSTCH TCH TCHTCH User rate at

    CS2 = 40.2 kbps

    TCH

    A Voice call takes the GPRS TS

    User rate at

    CS2 = 26.8 kbps

    Site with one carrier will be able to share timeslots (Voice and GPRS)

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    BTS

    BCCH GPRS GPRS GPRS GPRS GPRS GPRS GPRS

    MAX

    CS2 = 93.8 kbps

    BTS

    BCCH TCH TCH TCH TCH TCH TCH

    CS2 = 13.4 kbps

    GPRS

    Dynamic allocation of channels between circuit and packet:

    Channel sharing

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    (And more economical)

    ADVANTAGES OF GPRS

    1. Faster data transfer rates up to 115 kbps bydedicating all 8 time slots to GPRS

    GPRSGSM

    Higher data rate

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    ADVANTAGES OF GPRS

    2. Always on connection :

    Eliminates lengthy delays required to

    reconnect to the network to send andreceive data

    Information can be pushed to the end user

    in real time Bill by the packet (data exchanged) and

    type of service rather than by minute

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    ADVANTAGES OF GPRS

    3. Robust connectivity:

    First the coding scheme is

    selected depending on theradio conditions

    If error is detected in a framereceived in the BSS, the frame

    is retransmitted until properlyreceived before passing it onthe GPRS core network

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    ADVANTAGES OF GPRS

    4. Broad application support

    Fully enable internet applications (e-mail, web

    access, instant messaging and file transfer) multimedia web content

    Chat, visual information, still images, movingimages and document sharing

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    ADVANTAGES OF GPRS

    5. Security support

    GPRS builds on the authentication and

    security model of GSM It enables an additional authentication

    using protocols like RADIUS before thesub is allowed to access to the internet or

    other data networks

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    EDGE(Enhanced Data Rate for GSM Evolution)

    Introduction Increase data rates up to 384 kbps

    Introduces a new modulation

    technique (8PSK) and channel coding The last step before UMTS

    It is built on an existing GSM/GPRS

    system

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    EDGE(Enhanced Data Rate for GSM Evolution)

    Have the same symbol rate of GMSK Each symbol is represented by 3 bits

    8PSK generates same interference on adjacent

    channels as GMSK. We use the same channel structure and width

    and frequency plan of GPRS

    The distance between symbols is shorter using8PSK than GMSK misinterpretation

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    EDGE(Enhanced Data Rate for GSM Evolution)

    Packet handling The ability of

    retransmission ofpackets with a morerobust coding scheme

    Unlike GPRS in which

    retransmission ofpackets is made withthe same codingscheme

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    EDGE(Enhanced Data Rate for GSM Evolution)

    Impact of EDGE on existing GSM/GPRS networks

    Hardware upgrade to the BSS (new transceiver ineach cell)

    Software upgrade to the BS and BSC No change in the core networks New terminals

    - Terminal which provides 8PSK in the uplink and

    the downlink- Terminal which provides GMSK in the uplinkand 8PSK in the downlink

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    GPRS -- COMPLEXITY

    SGSN

    GGSN

    Gb

    Gn

    Gc

    Gi

    Gs

    Gn

    HLR

    BSC

    MSC

    PSTN

    BTS

    BTS

    Abis A

    D

    Abis

    A

    PDN

    NEW

    NEWNEW

    NEW

    NEW

    NEW

    NEW

    NEW

    NEW

    NEWNEW

    NEW

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    EDGE -- EVOLUTION

    SGSN

    GGSN

    Gb

    Gn

    Gc

    Gi

    Gs

    Gn

    HLR

    BSC

    MSC

    PSTN

    BTS

    BTS

    Abis A

    D

    Abis

    A

    PDN

    NEW

    NEW

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    EDGE(Enhanced Data Rate for GSM Evolution)

    EDGE benefits Short-term benefits: Capacity and

    performance Easy implementation on a GSM/GPRS

    network Cost effective

    Increase the capacity and the data rateof GPRS

    Enabling new multimedia services

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    Evolution From GSM to UMTS