70
Giuseppe Bianchi

UMTS LTE technologies

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A introduction to various radio core and access technologies.

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  • Giuseppe Bianchi

  • Giuseppe Bianchi

    Use top & bottom as additional guard

    ! "

    # $ %&&'( "

    Frequency [MHz]

    890

    915

    935

    960

    UPLINKMS BS

    DOWNLINKBS MS

    890.2

    890.4

    guard band

    1 2 3 4 5 6 7 8

    ( ) ( )[ ]( ) ( )[ ]MHz12.02.935

    MHz12.02.890+=

    +=

    nnF

    nnF

    dwlink

    uplink

  • Giuseppe Bianchi

    35dB60dB

    Specification: 9dBIn practice, due to power control and shadowing, adjacent channelsCannot be used within the same cell

  • Giuseppe Bianchi

    !"#$% &

    &)&( " *+', !!!( " -

    &'()

    &'"

    )&. / +&'0

    timetimeslot0

    577 s

    timeslot7

    1 frame = 60/13 ms = 4.615 ms26 frames = 120 ms (this is the key number)

  • Giuseppe Bianchi

    ! "#$! "#$%%$$

    & '( & '(

    time577us 577us 577us 577us 577us 577us 577us 577us

    frequency

    200 KHz200 KHz200 KHz200 KHz200 KHz200 KHz

    200 KHz200 KHz

    200 KHzslot

    Total n. of channels: 992

  • Giuseppe Bianchi

    $)*+,,$)*+,,

    $"*

    1 2 34 51 +"

    1710-1785 MHz uplink; 1805-1880 MHz downlink #6 78 9 " .

    1740-1785 MHz uplink; 1835-1880 MHz downlink%&$%+,

    A total of 374 carriers (versus124 in GSM)-%+

    : . . .

    First and second operators @ 900 MHz; Third etc @1800 MHzDCS 1800 deployment (1996+):

    15 MHz (=75 carriers) to Wind; 7.5 (=37 carriers) to first and second operator (plus existing 27 GSM 900 carriers)

  • Giuseppe Bianchi

    -- ""

    .$%/.0$%1

    2 ( , , $0

    ; ( 0 $0 &

    23

    *'$+'&

  • Giuseppe Bianchi

    $./$./

    0 1 2 3 4 5 6 7UPLINK

    0 1 2 3 4 5 6 7 DOWNLINK

    - MS uses SAME slot number on uplink and downlink

    - Uplink and downlink carriers always have a 45 MHz separation-I.e. if uplink carrier is 894.2 downlink is 919.2

    -3 slot delay shift!!

    MS: no need to transmit and receive in the same time on two different frequencies!

  • Giuseppe Bianchi

    0#( /0#( /0011

    f1f2f3f4f5f6f7

    Hopping sequence (example): f1 f2 f5 f6 f3 f7 f4 f1

    Slow = on a per-frame basis- 1 hop per frame (4.615 ms) = 217 hops/second

    . ; = * > -

    ! ""

  • Giuseppe Bianchi

    GP8.25

    $$

    %&&

    34

    " "

    ? @ " * $

  • Giuseppe Bianchi

    2/"2/"

    6'7

    7 .

    8 A . A " . ; . $) ;

    7 D " ( ;

    (58

    ; " *, 6 > : A " -

    .

    E . F

    Because channel estimate reliable ONLY when the radio channel sounding is taken!

    Multipath fading rapidly changes the channel impulse response

  • Giuseppe Bianchi

    /(/(

    Different codes used in adjacent cells! Avoids training sequenceDisruption because of co-channel interference.

  • Giuseppe Bianchi

    0 34 50 34 5

    7.6 bits 4.9 bits

    156.75 bits; 162.2 bits

  • Giuseppe Bianchi

    &,"5&&3

    G6 . .

    A . )

    . . !H )

    G6 A . !H )

    2,,+59

    d

    1 2 3 4BTS downlink tx

    MS downlink rx 1 2 3 4

    1

    1

    MS uplink rx

    BTS uplink rx1

    Expected RX time!

  • Giuseppe Bianchi

    6/6/

    BTS timeMS time

    dwlink slot 1 dwlink slot 4

    dwlink slot 1 dwlink slot 4

    uplink slot 1

    uplink slot 1

    Maximum cell radius:

    KmCGTcd

    c

    dCGT

    rate

    bits

    rate

    bits 5.42708332

    25.83000002

    2

    ==

    Is there something wrong? (GSM says that cells go up to 35 km)

  • Giuseppe Bianchi

    # 6# 6

    &5*/1

    5. . "

    G6 A

    &" / $&!

    .

    6 7"

    6 7/ A

    I.e. transmit after 468.75 bitsafter downlink slot

    6 7/ &!

    Transmit after 405.75 bits time

    TA (transmitted in the SACCH)

    dwlink slot 4

    uplink slot 1MS timeTA

    dwlink slot 4

    uplink slot 1uplink slot 1

    BTS time

    TA avoids collision!

  • Giuseppe Bianchi

    /1 /1

    ":++53

    )

    ;+:++53

    )

    ;+:"3

    )$6 7

    ,"

    6 7/ )

    &&,+,3

    [ ][ ] [ ] [ ]kmskmsbitsbits

    cTAd 89.34/300000

    /2708335.31

    2===

    8.25 bits Guard time additionally available for imperfect sync (+/- error)

  • Giuseppe Bianchi

    0707505088

    TB8

    Trainingsequence

    41

    Data36

    TB3

    88 bit burst156.25 bit (0.577 ms)

    Access burst

    Solution: USE A DIFFERENT BURST FORMATAccess Burst: much longer Guard Period availabledrawback: much less space for useful information

    GP68.25

    No collision with subsequent slot for distances up to 37.8 km

  • Giuseppe Bianchi

    -" -"

    ,,*

    B . G

    7

    G

    C> : G

    G

    . . G

  • Giuseppe Bianchi

    #( )5#( )5

    /6'

  • Giuseppe Bianchi

    9 9 #)5#)5030377 1 1 :":"

    ?8&

    ) . . >

    : . E.g. Fc + Pi/2 Fc Pi/2

    % /&&%, 51

    . > . *> A / A -

    ) . . A 1 = vary phase of Pi/2 in 1 bit symbol0 = vary phase of Pi/2 in 1 bit symbol

    5 A " #B 6 7B 6 7B 1 4 2 > A . I

  • Giuseppe Bianchi

    9 9 #)5#)5030377 1 1 :":"

    $% /$&&%, 51

    7

    G A "

    ?. @ > A

    J

  • Giuseppe Bianchi

    9 9 #)5#)5030377 1 1 :":"

    Advantage: continuous phase modulation = lower spectrum occupancyDisadvantage: ISI

  • Giuseppe Bianchi

    $ 5$ 5

    ;,*6--!

    $&+"6--!

    #. %; G: :

    GP8.25

    TB3

    TB3

    Dummy BurstTraining

    sequence26

    Fixed bit pattern58

    Fixed bit pattern58

  • Giuseppe Bianchi

    65 65

    558# " . I

    >

    ,3: . .

    i.e. synchronize frame counter : G#: *G # : %&" -

    3 bits network code (operator) Important at international boundary, where same frequencies

    can be shared by different operators3 bits color codeTo avoid listening a signal from another cell, thinking it

    comes from the actual one!

    GP8.25

    TB3

    TB3

    Synchronization BurstTraining

    sequence64

    Sync data39

    Sync data39

  • Giuseppe Bianchi

    5

  • Giuseppe Bianchi

    ;/;/11

    6 . K A >

    #. % %.

    > %

    %> %

    5

    G

    #; . " ; G

    Physical channels(FDMA/TDMA)

    Logical channels(traffic channels, signalling (=control) channels)

  • Giuseppe Bianchi

    ;/;/

    / /

    frequency

    Physical Channel: data rate r, time slot i

    frequency

    #

    $ %

    Logical channel A: data rate r/3, time slot i, frame 3kLogical channel B: data rate 2r/3, time slot i, frame 3k+1, 3k+2

    Frame 8 Frame 9 Frame 10 Frame 11 Frame 12

  • Giuseppe Bianchi

    / /

    MS BSSC FACCH MS BSS ; SACCH MS BSS $ SDCCHDedicated Control channel (DCCH)BSSMS5PCH BSSMS7

    J AGCH MSBSS3 . 7

    RACHCommon Control channel (CCCH)BSSMS SCHBSSMSC> : FCCH BSSMSG BCCHBroadcast channelMS BSS6 : 3TCH/HMS BSS6 : TCH/FTraffic channel (TCH)

    Additional logical channels available for special purposes(SMS, group calls, )

  • Giuseppe Bianchi

    . 11/. 11/////

    Setup for an incoming call (callarriving from fixed network part -MS responds to a call)

    Steps:- paging for MS- MS responds on RACH- MS granted an SDCCH- authentication & ciphering on SDCCH- MS granted a TS (TCH/FACCH)- connection completed on FACCH- Data transmitted on TCH

  • Giuseppe Bianchi

    7,,

    55

  • Giuseppe Bianchi

    )!

  • Giuseppe Bianchi

    //

    Analogvoice

    A/D conversion8000 samples/s13 bit/sample

    Digital voice104 kbps

    160 voice samples(20 ms)

    (2080 bits)

    Speech CODER(8:1 compression) 260 bits block13 kbps

  • Giuseppe Bianchi

    $ $

    %+&+&@*/@1

    D A " L .

    6 A A *, . -

    AB.

  • Giuseppe Bianchi

    ))/))/

    182 bits 78 bits

    260 bits260 bits block divided into-Class I: important bits (182)

    -Class Ia: Most important 50-Class Ib: Less important 132

    -Class II: low importance bits (78)50 bits 3 132 bits 4

    Parity bitsTail bits(0000)

    First step: block coding for error detection in class Ia (errordiscard frame)Second step: convolutional coding for error correction

    378 bits

    Convolutional coding, r=1/2

    78 bits

    456 bits

    Coding: needed to move from 10-1 to 10-3 radio channel native BERdown to acceptable range (10-5 to 10-6) BER

  • Giuseppe Bianchi

    531/531/

    0 1 2 3 4 5 6 7

    8 9 10 11 12 13 14 15

    16 17 18 19 20 21 22 23

    .. .. .. .. .. .. .. ..

    .. .. .. .. .. .. .. ..

    .. .. .. .. .. .. .. ..

    .. .. .. .. .. .. .. ..

    448 449 450 451 452 453 454 455

    8

    57

    B1 B2 B3 B4 B5 B6 B7 B8

    8 blocks, each with 57 bits

  • Giuseppe Bianchi

    $/1/$/1/

    B1 B3B2 B4 B5 B7 B8B6 B1 B3B2 B4 B5 B7 B8B6 B1 B3B2 B4 B5 B7 B8B6

    Block n-1 Block n Block n+1

    nn BB 11

    5 / nn BB 4

    18 /

    115 /

    +nn BB 148 /+nn BB

    %%""1/1/

    GP8.25

    TB3

    S1

    S1

    Trainingsequence

    26TB3

    1=

    n

    xB nxB 4=

    PRICE TO PAY: delay!! (block spreaded over 8 bursts 37 ms)

  • Giuseppe Bianchi

    5# 5#

    A3

    C. . "

    B

  • Giuseppe Bianchi

    0))0))

    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

    TCH/F(07) TCH/F(07)

    SACCH(07) IDLE frame

    SACCH-0 SACCH-1 SACCH-2 SACCH-3 SACCH-4 SACCH-5 SACCH-6 SACCH-7

    1 SACCH burst (per TCH) every 26 frames (120 ms)

    4 . 6 .

  • Giuseppe Bianchi

    ))!"3))!"3

    55Block coding adds 40 bits (=224)4 tail (zero) bits (=228)1/2 Convolutional encoding (=456 bits)

    B*53

    , " ( +"

    37:

    . .

    I.e. which message to send in case of many messages, and on which paging slot (4 bursts)

    . " 3M

    To monitor PAGCH for Immediate Assignment message detection

    B&&5&G+

  • Giuseppe Bianchi

    7 7

    "%&*&&&

    8 ( A %; "

    &&,&

    2"/,1

    **+%,

    4 : : MS1ID1

    MS2

    ID2

    BTS

    ID1leave

    continues

  • Giuseppe Bianchi

    //// %% ==

    MS BTS BSC MSC

    Immediate_assignment

    Initial_message

    MS ID (IMSI or TMSI), MS capabilities(=classmark), establishment cause

    Initial_message_ack (UA)Copy of Initial message (including MS ID)

    Establishment_indication

    Further signaling: MSC to MS

  • Giuseppe Bianchi

    %%$$ ))

    ))%% $))!$))!

    %

    "

    !%--!

    -53%--!

    , &" A "

    +,&5/%--!)1

    , : : *H , 7: : - *%6 -

    : : . $. .

    184 bits / (51*8*15/26 ms) = 598/765 kbps ~ 782 bit/s 7: : A . .

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    +

    SDCCH/4 for smallcells SDCCH shares

    BCCH+PAGCH channel- see before -