Issuu

Um Inte rfa ce a nd Ra dio Cha nne ls www.huawei.com

Conte nts 1.

Overview

Processing of Voice Signal

Radio Channel

Page2

Ra dio Inte rfa ce Another MSC PSTN ISDN

BTS BSC MS

A-bis

MSC/VLR

HLR/AUC

SMC

OMC

Page3

Hie ra rchica l S tructure of Um Inte rfa ce Communication management (CM) Network application layer (L3) Mobility and security management (MM) Radio resources management (RR)

Data link layer (L2)

RACH

Physical link layer (L1)

Integrated management

BCCH

AGCH/PCH

SDCCH

SACCH

TCH

TCH0 TCH1 TCH2 。。 SACCH 。。 TCH23 IDL Multiframe

Page4

FACCH

Ra dio Acce s s Te chnology CDMA Time CDMA

Power Tim

TDMA

Power

Tim

U Us ser Us User er Us e r UU e s Us esrer r er y Tim e

Frequency

Time TDMA

Power

FDMA

eq Fr

Code

y nc ue

c en u eq Fr

y nc e qu Fre

Frequency

Time FDMA Frequency

Page5

Conte nts 1.

Overview

Processing of Voice Signal

Radio Channel

Page7

Voice S igna l P roce s s ing 8KHz,13bi t

13kbit/s 20 ms

Voice (A/D) A/D)

Segmentation

Speech coding

Channel coding

22.8kbit/s

33.8kbit/s

Interleaving

Encryption) Encryption)

Burst formatting

Modulation

Page8

Transmission

Ana log-Digita l Conve rs ion

Page9

S pe e ch Coding 



The Enhanc e Full Rate coding mode is called CELP (C o de Ex c ite d Line ar Pre dic tiv e C o ding ) The Full Rate coding mode is called RPE-LTP (Re g ular Puls e Ex c ite d- Lo ng Te rm Pre dic tio n). The Half Rate coding mode is called VCELP (Ve c to r- Sum Ex c ite d Line ar Pre dic tio n )

8KHz,13bi t

20 ms

244 bits(EFR) 260 bits(FR) 112 bits(HR)

Voice (A/D) A/D)

Segmentation

Speech coding

Page10

12.2kbit/s 13kbit/s 5.6kbit/s

Cha nne l Coding Block Coder

1:2 Convolutional Coder

8KHz,13bi t

20 ms

244 bits(EFR) 260 bits(FR) 112 bits(HR)

12.2kbit/s 13kbit/s 456bits(FR/EFR) 22.8kbit/s 228bits(HR) 11.4kbit/s 5.6kbit/s

Voice (A/D) A/D)

Segmentation

Speech coding

Channel coding

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Inte rle a ving

1 2 3 4 5 6 7 8 ...

First interleaving:

....

... 452 453 454 455 456

1 9

2 10

3 11

4 12

5 13

6 14

7 15

8 16

. .

. 449

. 450

. 451

. 452

. 453

. 454

. 455

. 456

....

Second interleaving:

{A4,B0}

{A5,B1}

{A6,B2}

{A7,B3}

{B4,C0}

{B5,C1}

{B6,C2}

Page12

{B7,C3}

Voice Burs t Tail bit

Training sequence

Data

3 57 encrypted bits bits

8KHz,13bit

Voice

(A/D) A/D)

26 bits

Dat a

Tail bit

Guard period

3 1 57 encrypted bits bits 8.25 bits

13kbit/ s

20 ms Segmentation Speech coding

Channel coding

22.8kbit/s

33.8kbit/ s Interleaving

Encryption) Encryption)

Burst formatting

Transmission Modulation

Page14

Voice S igna l P roce s s ing Mobile equipment GSM Network Speaker

Transmitter Modulator 33.8 kbit/s Burst formatting Ciphering Interleaving 22.8 kbit/s Channel coding 13 kbit/s Speech coding Segmentation 8 kHz 13 bits A/D-conversion Microphone

Receiver Demodulator

Transmitter Modulator

Adaptive Equalization

De-ciphering De-interleaving

Burst formatting Ciphering Interleaving

Channel decoding

Channel Decoding

Speech decoding

Receiving part

D/A-conversion Receiving part

Channel coding 13 kbit/s D/D-conversion 8 kHz 8 bits 64 kbit/s PCM Transmitting part

Transmitting part

Page15

Timing Adva nce (TA) The mobile phone should send the signal in advance!!

TA Transmission delay t

Transmission delay t

Page16

Fre que ncy Hopping Frequency f0 f1 f2 f3 f4 Frame

Time

Page18

DTX 



DTX: Discontinuous Transmission 

Shut off the transmission at voice intervals;



Only transmit SID frames’



The transcoder at the RX terminal produces comfortable noise.

VAD: Voice Activity Detection 

Implemented by the transcoder.

Prolong battery life and reduce interference

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P owe r Control 

Prolong battery life



Reduce network interference



Include both uplink power control and downlink power control



Level and quality are taken into account



BSC or BTS is the final adjudicator Signal level

Target level value: e.g. -85 dm

BCCH Carrier is not involved in power control.

Time

Page22

Conte nts 1.

Overview

Processing of Voice Signal

Radio Channel

Page23

Fra me a nd Cha nne l Frequency

200kHz

Time

Page24

P hys ica l Cha nne l of Logica l Cha nne l TDMA FRAME

200K 577 µs

Physical Channel Logical channel Logical channel

different message types

Logical channel Logical channel Logical channel

Page25

Burs t •

Access burst (AB): Used in MS initial access Tail bit

8bit

•

41 synchronous bits

Data Tail bit 36 encrypted 3bit bits

Guard interval

68.25bit

Frequency correction burst (FB): Used in frequency synchronization between MS and BTS Tail bit

Data

3bit

142bit

Tail bit Guard interval

3bit

8.25bit

Synchronous burst (SB): Used in timing synchronization between MS and BTS Tail bit

3bit

Data 39 encrypted bits

64 synchronous bits

Data Tail bit Guard interval 39 encrypted 3bit 8.25bit bits

Page26

Burs t Normal burst (NB)





Used to carry the information of the traffic channel and the control channel except for RACH

Tail bit

3bit

Data

Training sequence

57 encrypted bits

1 26bit 1

Data

Tail bit Guard interval

57 encrypted bits

3bit

8.25bit

Frame stealing flag 

Dummy burst (DB) 

Used in transmission of filling frames by BTS at timeslots when there is no information delivered

Tail bit

3bit

Tail bit Guard interval 142 modulation bits

3bit

Page27

8.25bit

Logica l Cha nne l Type GSM900 and DCS1800 have the same logical channel category



Logical channel

Dedicated channel (DCH)

Common channel (CCH)

Broadcast control channel (BCH)

FCCH

SCH

BCCH (system information)

Common control channel (CCCH)

PCH

AGCH

RACH

Voice channel (TCH)

Control channel

SDCCH

FACCH

SACCH

Page28

TCH/F

TCH/H

Downlink Logica l Cha nne l Common Channel

BCCH

FCCH SCH BCCH

CCCH

PCH AGCH

SDCCH

Dedicated Channel

DCCH

SACCH FACCH

TCH

TCH/F TCH/H

Page29

Uplink Logica l Cha nne l

RACH

CCCH

Common channel

SDCCH SACCH

DCCH

FACCH TCH/F TCH/H

Dedicated channel

TCH

Page31

Us e of Logica l Cha nne ls Power-on

FCCH

Search for frequency correction burst

SCH

Search for synchronous burst

BCCH

Listen to the system information Idle mode

Dedicated mode

PCH

Monitor paging message Send access burst

RACH

Allocate signaling channel

AGCH

Set up the call

SDCCH

Allocate voice channel

SDCCH

Conversation

TCH FACCH

Release the call Idle mode

Page33

P hys ica l Combina tion of Logica l Cha nne l 26-frame multi-frame TCH/F+FACCH/F+SACCH/F (full-rate TCH) TCH/H+FACCH/H+SACCH/H (half-rate TCH)

51-frames multi-frame FCCH+SCH+BCCH+CCCH (main BCCH) FCCH+SCH+BCCH+CCCH+SDCCH/4+SACCH/4 (combined BCCH) BCCH+CCCH (extended BCCH) SDCCH/8+SACCH/8 (main SDCCH)

Page34

S tructure of Ma in BCCH 1 multi-frame (51TDMA Frames) 235.38ms Downlink Group3,4

Group

Group1

(same

Group2

Grpup5

as Group2)

Channel Frame Number

BX4

CX4

……

CX4

2-5

6-9

12-15

16-19

20-39

42-45

46-49

1 multi-frame (51TDMA Frames) 235.38ms Uplink R

R……R

13-46

Page35

S tructure of Combine d BCCH 1 multi-frame (51TDMA Frames) 235.38ms Downlink Group

Group1

Channel

Frame Number

Group2

B×

C×

B×

C×

2-5

6-9

Group3

C×

12-

16-

Group4

×4

22-

26-

1 multi-frame (51TDMA Frames) 235.38ms

Grpup5

×4

32-

36-

×4

42-

46-

Uplink

Channel

D3×4

A2×4

A3×4

R……R

D0×4

D1×4

D2×4

Channel

D0×4

A0×4

A1×4

R……R

D0×4

D1×4

D2×4

0-3

6-9

10-13

14-36

37-40

41-44

47-50

Frame Number

Page36

S tructure of Logica l Cha nne l Combina tion Fra me -Ma in S DCCH 1 multi-frame (51TDMA Frames) 235.38ms Downlink Channel

Channel Frame Number

D0×

D1×

D2×

D3×

D4×

D5×

D6×

D7×

A0×

A1×

A2×

A3×

D0×

D1×

D2×

D3×

D4×

D5×

D6×

D7×

A4×

A5×

A6×

A7×

0-3

4-7

8-11

12-

16-

20-

24-

28-

32-

36-

40-

44-

1 multi-frame (51TDMA Frames) 235.38ms Uplink Channel

Channel Frame Number

A5×

A6×

A7×

A1×

A2×

A3×

0-3

4-7

8-11

D0×

D2×

D3×

D4×

D5×

D6×

D7×

A0×

×4

D0×

D2×

D3×

D4×

D5×

D6×

D7×

A4×

×4

15-

19-

23-

27-

31-

35-

39-

43-

47-

Page37

S tructure of Logica l Cha nne l Combina tion Fra me -TCH Case of one full rate TCH 1 multi-frame (26TDMA Frames) 120ms Channel Frame Number

T…T

6…11

T,,,T 13… 18

Case of two half rate TCHs 1 multi-frame (26TDMA Frames) 120ms Channel Frame Number

T…t

6…11

T,,,t 13… 18

Page38

Fra me 1 hyper frame=2048 super-frames=2715648TDMA frames (3 hours, 28 minutes, 53 seconds and 760 milliseconds) 0

TCH SACCH/T FACCH

2045

2044

2046

1 super-frame=1326TDMA frames (6.12 seconds) 1

0 0

1 multiframe=26TDMA frames (120ms) 0

2047 BCCH CCCH SDCCH

1 multiframe=51TDMA frames (3060/13ms) 25

1TDMA frame=8 timeslots (120/26=4.615ms) 2 3 4 5 6

1 timeslot=156.25 bit duration (15/26=0.577ms) (1 bit duration: 48/13=3.68us) 26 training TB 58 information bits sequences 3 Frequency correction burst (FB) TB Constant bit 142 3 TB Information bit 39 Extended training sequence 64 Synchronous burst (SB) 3 TB Synchronous sequence 41 TB Information bit 36 3 Access burst (AB) 3

Normal burst (NB)

58 information bits

Information bit 39

TB 3 TB 3

GP 8.25 GP 8.25

TB GP 3 8.25

GP 68.25

Page39

TB: Tail bit GP: Guard period

Configura tion of Common Control Cha nne l

Downlink CCCH

PCH

Uplink CCCH

AGCH

RACH

How to determine the total CCCH resources of the cell? How to allocate AGCH and PCH reasonably?

Page41

S umma ry 

In this course, we have learned: 

Processing of Voice Signal



Radio Channel in Um Interface



Key Technical in Um Interface

Page42

Thank you www.huawei.com