Frequency [MHz] ! " # $ %& &'( " Use top & bottom as additional guard. guard band. Giuseppe Bianchi DOWNLINK BS MS UPLINK MS BS

(1)

(2)

Giuseppe Bianchi

Use top & bottom as additional guard

! " # $ % & &' ( " Frequency [MHz] 890 915 935 960 UPLINK MS BS DOWNLINK BS MS 890.2 890.4 “guard band” 1 2 3 4 5 6 7 8

( )

[

(

)

]

( )

[

935 .

2

0 .

2 ( )

1 ]

MHz

1

2 .

0

2 .

890 −

+

=

−

+

=

n

F

n

F

dwlink uplink

(3)

Giuseppe Bianchi

35dB 60dB

Specification: 9dB

In practice, due to power control and shadowing, adjacent channels Cannot be used within the same cell…

(4)

Giuseppe Bianchi ! " # $ % & & )& ( " * + ', !!! ( " -& ' ( ) &' " ) & . / +&'0 µ time time slot 0 577 µs time slot 7 1 frame = 60/13 ms = 4.615 ms

(5)

Giuseppe Bianchi

! "

#$

! "

#$

%

$

& ' ( & ' ( time

577us 577us 577us 577us 577us 577us 577us 577us frequency 200 KHz 200 KHz 200 KHz 200 KHz 200 KHz 200 KHz 200 KHz 200 KHz 200 KHz slot Total n. of channels: 992

(6)

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 MHz DCS 1800 deployment (1996+):

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

(7)

Giuseppe Bianchi

--

"

.

$%

/.0$% 1

2 ( , , $0

;

( 0

$0 &

2

3 *

' $ +'&

< & ' $ &+'&

;

-,

* +, ', $ , &

< , , ', $ 0 &

;

(8)

-Giuseppe Bianchi

$

. /

$

. /

0 1 2 3 4 5 6 7 UPLINK 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!

(9)

Giuseppe Bianchi

0 #

(

/

0 #

(

/

0

1

f1 f2 f3 f4 f5 f6 f7

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

. ; = * >

(10)

Giuseppe Bianchi GP 8.25

$

% && 3 4 " " ? @ " * $ < -? @ " A & . * . -22.8 kbps gross rate 13 kbps net rate! %3 5 7 % " B " C7: : * " -TB 3 DATA57 S1 S1 Training sequence 26 Data 57 TB3 148 bit burst 156.25 bit (15/26 ms = 0.577 ms) Normal burst

(11)

Giuseppe Bianchi

2 / "

6 ' 7 7 . 8 A . A " . ; . $ ) ; 7 D " ( ; ( 5 8 ; " *, 6 > : A " -. E . F

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

(12)

Giuseppe Bianchi

/

(

/

(

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

(13)

Giuseppe Bianchi

0

3

4

5

0

3

4

5

7.6 bits 4.9 bits

(14)

Giuseppe Bianchi & , " 5 & &3 G6 . . A . ) . . !H ) G6 A . !H ) 2,, + 5 9 d 1 2 3 4 BTS downlink tx MS downlink rx 1 2 3 4 1 1 MS uplink rx BTS uplink rx 1 Expected RX time!

(15)

Giuseppe Bianchi

6 /

BTS time

MS time

dwlink slot 1

…

dwlink slot 4

dwlink slot 1

…

dwlink slot 4

uplink slot 1

…

Maximum cell radius:

Km

C

GT

c

d

c

d

C

GT

rate bits rate bits

₄

_.

₅

270833

2

25 .

8 300000

2

2 _≈

⋅

≈

⋅

=

→

=

(16)

Giuseppe Bianchi

#

6 #

6

& 5 * / 1 5 . . " G6 A & " / $&! . 6 7 " 6 7/ A

I.e. transmit after 468.75 bits after downlink slot

6 7/ &!

Transmit after 405.75 bits time

TA (transmitted in the SACCH)

dwlink slot 4

uplink slot 1 MS time

TA dwlink slot 4 uplink slot 1 uplink slot 1 BTS time TA avoids collision!

(17)

Giuseppe Bianchi

/

1 /

1

" :+ + 5 3 ) ;+ :+ + 5 3 ) ;+ : " 3 ) $6 7 , " 6 7 / ) & & , + , 3

[ ]

[

bits

s

]

[

km

s

]

[ ]

km

bits

c

TA

d

300000

/

34 .

89 /

270833

5 .

31

2 ⋅

=

⋅

=

(18)

Giuseppe Bianchi

0

7

0

7

5

0

5

0

8

TB 8 Training sequence 41 Data 36 TB3 88 bit burst 156.25 bit (0.577 ms) Access burst

Solution: USE A DIFFERENT BURST FORMAT

Access Burst: much longer Guard Period available drawback: much less space for useful information

GP 68.25

(19)

Giuseppe Bianchi

-

"

-

"

,

*

B

.

G

7 G

C >

:

G

. .

G

(20)

Giuseppe Bianchi

#

(

)

5 #

(

)

5 / 6' <

1 ,

$ % &

3 ; A

H & )

(

*&+'+ , ! (

-=

>

E

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%

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+

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,

, 8

GP 8.25 TB

3 Fixed bit pattern (all 0s)142 TB3 Frequency Correction Burst

(21)

Giuseppe Bianchi

9

9 #)5

#)5

0

3

7

1

1 : "

: "

? 8

&

)

.

>

:

.

E.g. Fc + Pi/2 Fc – Pi/2

% /

& & % ,

51 .

>

.

*

>

A

/

A

-)

.

A

1 = vary phase of Pi/2 in 1 bit symbol 0 = vary phase of –Pi/2 in 1 bit symbol

5 A

" #B 6 7B 6 7B 1 4 2

>

(22)

Giuseppe Bianchi

9

9 #)5

#)5

0

3

7

1

1 : "

: "

$ % /$

& & % ,

51

7 G

A

"

? .

@

>

A

J

(23)

Giuseppe Bianchi

9

9 #)5

#)5

0

3

7

1

1 : "

: "

Advantage: continuous phase modulation = lower spectrum occupancy Disadvantage: ISI

(24)

Giuseppe Bianchi

$

5 $

5 ;

,

*

6--!

$

&

+ "

6--!

#.

% ;

G: :

GP 8.25 TB 3 TB3 Dummy Burst Training sequence 26 Fixed bit pattern

(25)

Giuseppe Bianchi

6

5

6

5

8 #

"

.

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 operators

3 bits color code

To avoid listening a signal from another cell, thinking it comes from the actual one!

GP 8.25 TB 3 TB3 Synchronization Burst Training sequence 64 Sync data 39 Sync data39

(26)

Giuseppe Bianchi

5

(27)

Giuseppe Bianchi

; /

1

6 . K A > # . % % . > % % > % 5 G # ; . " ; G Physical channels (FDMA/TDMA) Logical channels

(28)

Giuseppe Bianchi

; /

/

frequency

Physical Channel: data rate r, time slot i

frequency

# $

%

Logical channel A: data rate r/3, time slot i, frame 3k

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

(29)

Giuseppe Bianchi

/

MS BSS C FACCH MS BSS ; SACCH MS BSS $ SDCCH

Dedicated Control channel (DCCH)

BSS MS 5 PCH BSS MS 7 J AGCH MS BSS 3 . 7 RACH Common Control channel (CCCH)

BSS MS SCH BSS MS C > : FCCH BSS MS G BCCH Broadcast channel MS BSS 6 : 3 TCH/H MS BSS 6 : TCH/F Traffic channel (TCH)

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

(30)

Giuseppe Bianchi

.

1 1 /

.

1 1 /

/

Setup for an incoming call (call arriving 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

(31)

Giuseppe Bianchi

7 ,

,

(32)

Giuseppe Bianchi

)!<#

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

Periodic pattern of 26 frames (120 ms = 15/26 ms/TS * 8 TS/frame* 26 frame)

24 TCH frames over 26

2

0 1 3 4 5 6 7 0 1 3 4 5 6 72 0 1 3 4 5 6 72 0 1 3 4 5 6 72

Same TS in every frame

GP 8.25 TB

3 DATA57 S1 Seq. (26)Training S1 Data₅₇ TB₃ 148 bit burst

156.25 bit (0.577 ms)

Theoretical rate: 1/8 channel rate: r=33.85 kbps 2 signalling frames: r 31.25 kbps

Burst overhead (114 bits over 156.25): r 22.8 kbps

(33)

Giuseppe Bianchi

/

Analog voice A/D conversion 8000 samples/s 13 bit/sample Digital voice 104 kbps 160 voice samples (20 ms) (2080 bits) Speech CODER

(34)

Giuseppe Bianchi

$

%+ &+ & @ * /@ 1 D A " L . 6 A A *, . -A B .< & A " . 3 C * 3 59 A . ; ? . @ : . A " 6 M 7 * , . - . . * # / -time

(35)

Giuseppe Bianchi

)

/

)

/

182 bits 78 bits

260 bits

260 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 bits

Tail bits(0000)

First step: block coding for error detection in class Ia (error discard 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 BER}

(36)

Giuseppe Bianchi

5

3 1 /

5

3 1 /

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

(37)

Giuseppe Bianchi

$

/

1 /

$

/

1 /

B1B2B3B4 B5B6B7 B8 B1B2B3B4 B5B6B7 B8 B1B2B3B4 B5B6B7 B8

Block n-1 Block n Block n+1

n n _B B 1 ₁ 5− / … … B₈n−1 /B₄n B₅n /B₁n+1 … … B₈n /B₄n+1

%

"

1 /

GP 8.25 TB 3 S1 S1 Training sequence 26 TB 3 1 −

=

n x

B

n x

B

₋₄

=

(38)

Giuseppe Bianchi

5 #

A

3 C .

.

"

B

<

&

+

, &

A

B

.

&

A GC#

(39)

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(0…7) TCH/F(0…7)

SACCH(0…7) 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)

(40)

Giuseppe Bianchi

))! "

3 ))! "

3

5

Block coding adds 40 bits (=224) 4 tail (zero) bits (=228)

1/2 Convolutional encoding (=456 bits)

B

* 53

, "

(

+ "

<

A "

"

/

7: :

"

( I

% --!

3 , "

) , .

/ !, !'! " )

B1 B2 B3 B4 B5 B6 B7 B8 Odd/even interleaving 104 frames = 480 ms

(41)

Giuseppe Bianchi

))!

' 7 " * & 5 * & + , :8 & + , * & 5 & A * + 3 % % E I free free

(21 bytes – datalink layer) Includes measurement reports

0 1 2 3 4 5 6 7

Power level Timing advance

(42)

Giuseppe Bianchi

0

% ) + " 2 ; . . . & & 6 + * ( & + :+ " & : 6 % , : %* % --! 5 ; A A $ 0 = 43 dBm (20 W) 15 = 13 dBm (20 mW) 5 &3 & , + , G : + " ++ " : Maximum power (defined by class) Minimum power (13 dBm for GSM) (0 dBm for DCS 1800) 2 dB steps;

(43)

Giuseppe Bianchi

1

1 CD .@

5 ; A 5 H "

-CDE;

G 1 3 * ; --48 RXLEV_63 -48 -49 RXLEV_62 … … … … … … -107 -108 RXLEV_3 -108 -109 RXLEV_2 -109 -110 RXLEV_1 -110 -RXLEV_0 To (dBm) From (dBm) RX signal level -12.8 RXQUAL_7 12.8 6.4 RXQUAL_6 6.4 3.2 RXQUAL_5 3.2 1.6 RXQUAL_4 1.6 0.8 RXQUAL_3 0.8 0.4 RXQUAL_2 0.4 0.2 RXQUAL_1 0.2 -RXQUAL_0 To (%) From (%) Bit error Ratio

(44)

Giuseppe Bianchi

#

)

#

)

? --!3 5 5 5 2 ; A . " . Call setup Handover ? --! :' & B * * : , " C + * :/ & 1 -! D " D " ( * -& -& ? --! , N&) O" ). P / 0 ' ( " *A !, ! " 7: :

(45)

I-Giuseppe Bianchi

# ))!

)!

# ))!

)!

Via Stealing bits

- upper bit = odd bits stolen - lower bit = even bits stolen - both bits = all burst stolen

time

Figure: shows example of 2 FACCH blocks stealing a TCH (note begin and end behavior due to interleaving)

(46)

Giuseppe Bianchi

!

%

)!<!

% ++

,

(: + *

%+

,

FF

:

"

.

A

95 bits class I

» + 3 parity + 6 tail + convolutional coding 104/211 17 bits class 2

B

* 53

.

A

*"

( H

H

) A

-G

"

? &

53

5 6 3 4 1 2 7 8 9 10 11 12 TCH/H 0…7

(47)

Giuseppe Bianchi

--!

G

0 '& ( "

*

%

-4

Q ' < ', < 0 '&<

' <

,

5 *

-G

,

"

*

3 #

A

;

/ 0

*III-.

"

A

"

*

(

A

(48)

-Giuseppe Bianchi

6

(49)

-Giuseppe Bianchi C G G G G 5 5 5 5 C 5 5 5 5 5 5 5 5 C 5 5 5 5 5 5 5 5 C 5 5 5 5 5 5 5 5 C 5 5 5 5 5 5 5 5

5 )

/

6 /

6

, & * ( ! '!, . *A . -% 0 : " , & ; C > : : *C: : -#. . ; " : * : -2 , & ! " ! # " 3 R R %!% % G: : 3 . 5 *5: - ) 7 J *7J : - O/ 57J : P

51 frame structure - downlink

(50)

Giuseppe Bianchi

5))!

2 "

:

(

3 . 7

:

3 3 3 3 3 3 3 3 3 3 3

51 frame structure - uplink

2 , 8

+

/

1 ;% 6.

&

%

H

2 &

&

-!

Provided that:

• All empty slots are filled with DUMMY bursts • Downlink power control must be disabled

3

(51)

Giuseppe Bianchi

0 /

First operation when MS turned ON: spectrum analysis

(either on list of up to 32 Radio Frequency Channel Numbers of current network) (or on whole 124 carriers spectrum)

(52)

Giuseppe Bianchi

/

%

5 ,

+

" * /?--!1

:

"

C

B&&

,

" %-!

C

*& "

>

-3

"

25 bits (+ 10 parity + 4 tail + ½ convolutional coding = 78 bits)

6 bits: BSIC

19 bits: Frame Number (reduced)

(53)

Giuseppe Bianchi

%

/

0 1 2 3 4 5 6 7 8 TS, 4.615 ms C GGGG5 555 C 5 5555 555C 5 5555 555C 5 5555 555C 5 5555 555 T T T T T T T T T T T TS T T T T T T T T T T T T

1 multiframe = 26 TDMA frames (120 ms) 1 multiframe = 51 TDMA frames (235.38 ms)

Multiframe 0 Multiframe 1 Multiframe 2 Multiframe 49 Multiframe 50 Multiframe 0 Multiframe 1 Multiframe 25

………

…

1 superframe = 51 x 26-multiframe or 26 x 51-multiframe (1326 TDMA frames, 6.12 s)

superframe 0 superframe 1 superframe 2 superframe 2046 superframe 2047 1 hyperframe = 2048 superframe (2715648 TDMA frames, 3h28m53s.76)

(54)

Giuseppe Bianchi

9 " 7

? &

H

.

, &

H

.

; G: :

I.e. which specific information transmitted on BCCH during a given multiframe

% + , &

H

2 .

"

.

Superframe # Multiframe # frame #

(55)

Giuseppe Bianchi

5))!

: & " " . A 7: : G: : 184 bits / (51*8*15/26 ms) ~ 782 bps B , & + * 5 . "

Random access backoff values

Maximum power an MS may access (MS_TXPWR_MAX_CCCH) Minimum received power at MS (RXLEV_ACCESS_MIN)

Is cell allowed? (CELL_BAR_ACCESS) Etc.

8

Needed if frequency hopping is applied

(56)

Giuseppe Bianchi

1

1 /

6 /

6

C G G G G 5 5 5 5 C 5 5 5 5 5 5 5 5 C C C

51 frame structure – small capacity cell

3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 DOWN UP G G G G 5 5 5 5 5 5 5 5 5 5 5 5 DOWN

51 frame structure – large capacity cell

5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3

Used in TS 2 (and, eventually, 4 and 6) of beacon carrier Provides additional paging and RACH channels

Integrates SDCCH in same channel as other control information Leaves additional TS all available for TCH

(57)

Giuseppe Bianchi

9 =>

?*7

9 =>

?*7

Last frame (idle) in TCH multiframe (Frame #25) used as “search frame”!

T T T T T T T T T T T T S T T T T T T T T T T T T

- An active call transmits/receive in 25 frames, except the last one.

- in this last frame, it can monitor the BCCH of this (and neighbor) cell

- this particular numbering allows to scan all BCCH slots during a superframe - important slots while call is active: frequency correction FCCH and sync SCH! - needed for handover

-Worst case: at most every 11 TCH multiframes (1.32 s), there will be a frequency correction burst of a neighboring cell

(58)

Giuseppe Bianchi

5 5<C

&

<

(59)

Giuseppe Bianchi

9 / /

:

.

only upon explicit request from MS

5

needed to “wake-up” MS from IDLE state when incoming call arrives to MS

37:

(

Generally SDCCH (but immediate TCH assignment is possible) BSS/MSC MS 1) paging 3) Channel assignment 2) Random access Paging channel: PCH

Access Grant Channel: AGCH Random Access Channel: RACH

PAGCH CCCH_{Common Control} CHannel

(60)

Giuseppe Bianchi

/ /

5 5&

5 5

%-E

A

.

,

,6%-5

.

S

5 .

List of cells where paging should be performed Identity of paged user (IMSI or TMSI)

5 5&

5 *

*

,

.

)

A

7: :

* ,

& "

-5 -5, &

% &

G

(61)

Giuseppe Bianchi

$

$ @

$

$ @

% & + 5 5 * < -! * 0 " A " ! # # 2 A " $

Switches off otherwise

-! 0 + &&

6--!

2 0 " $

C G G G G 5 5 5 5 C 5 5 5 5 5 5 5 5 C 5 5 5 5 5 5 5 5 C 5 5 5 5 5 5 5 5 C 5 5 5 5 5 5 5 5

(62)

Giuseppe Bianchi " * % # * . -E " . E ; " 6 C -! 7 " , " * T > - !& "

+6 parity; + 4 tail; + ½ convolutional coding

TB

8 Seq. (41)Training Data₃₆ TB₃ Access burst GP 68.25 $ % & ' # 100: response to radio call

101: emergency call

110: new establishment of call

111: supplementary service (SMS, etc) …

000: other case

Random discriminator: (0…31) value randomly generated by MS

(63)

Giuseppe Bianchi

)!

A,B C,B C A,B A B MS-A _MS-B MS-C

Multiple Access Technique for simultaneous access Collision resolution based on

- random retrial period - “permission” probability (SLOTTED ALOHA protocol)

(64)

Giuseppe Bianchi

)!

I

.

&

"

+

3 %

A

% A

)

*

+

3 (

)

(

)

(

)

= − −

−

N k k N k N N

p

k

N

p

Np

p

2 1

1 :

collision

1 :

success

1 :

idle

(65)

Giuseppe Bianchi

)!

6--!

G (

.

uniform distribution; max value: 3 to 50

. .

. "

.

Never greater than 7

+

,3

.

A

*

/

-37:

MSs divided into 10 groups, depending on SIM-related information

BTS may block selected groups

Allows to reduce RACH load down to as low as 10% » Emergency calls bypass this rule…

(66)

Giuseppe Bianchi

/

%

*

MS BTS BSC MSC Channel_request rnd number Channel_required rnd&frame number,

Delay (TA estimate)

Channel_activation Ch_activation_ack

rnd&frame number, channel description, Initial TA, initial max power

(67)

Giuseppe Bianchi

/

+ 5 5

#' ' 7J :

.

– name PAGCH is perhaps better…

%

=

+

>

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

(68)

Giuseppe Bianchi

7

" % & * & & &

8 ( A % ; "

& & , &

2 " / , 1 * * + % , 4 : : MS1 ID1 MS2 ID2 BTS ID1 leave continues

(69)

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

(70)

Giuseppe Bianchi

%

$

)

%

_%

$))!

_$))!

% " ! % --! - 53 % --! , & " A " + , & 5/% --!) 1 , : : *H , 7: : - * %6 -: -: . $. . 184 bits / (51*8*15/26 ms) = 598/765 kbps ~ 782 bit/s 7: : A . .

! ! ! ! & & & & + + + +

7 7 7 7 ! 7 7 7 7 ! 7 7 7 7 ! 7 7 7 7 !

! ! ! ! & & & & + + + +

7 7 7 & 7 + 7 7 7 & 7 + 7 7 7 & 7 + 7 7 7 & 7 + SDCCH/4 for small cells – SDCCH shares BCCH+PAGCH channel see before