Gsm Radio Interface Issue2.22 e&s[1]

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Copyright © 2011 Huawei Technologies Co., Ltd. All rights reserved.

GSM Radio Interface

Copyright © 2011 Huawei Technologies Co., Ltd. All rights reserved. Page3

Contents

1. Overview

2. Processing of Voice Signal

3. Radio Channel


Radio Interface

Another MSC

HLR/AUC

SMC

PSTN ISDN

OMC

MS

Um

MS

A-bis

BSC

A

BTS

MSC/VLR


Communication management (CM)Communication management (CM)

Radio resources management (RR)Radio resources management (RR)

Mobility and security management (MM)

Mobility and security management (MM)

Integrated managementIntegrated management

TCH0 TCH1 TCH2 。。 SACCH 。。 TCH23 IDLTCH0 TCH1 TCH2 。。 SACCH 。。 TCH23 IDL

Multiframe

Physical link layer (L1)

Data link layer (L2)

Network application layer (L3)

Hierarchical Structure of Um Interface

RACH BCCH AGCH/PCH SDCCH SACCH TCH FACCH


Radio Access Technology

FrequencyTime

Power

FrequencyTime

Power

FrequencyTime

Power

FDMA

TDMA

CDMA

User

User User

User

User User

User

User

TimeFDMA

Frequency

TDMATime

Frequency

CDMA

Frequency

Time

Code


Contents

1. Overview


3. Radio Channel


Voice Signal Processing

(A/D)

20 ms

22.8kbit/s

13kbit/s8KHz,13bit

33.8kbit/s

Segmentation Speech coding Channel coding

Interleaving Encryption) Burst formatting Modulation

Transmission

Voice


Analog-Digital Conversion


Speech Coding

The Enhance Full Rate coding mode is called CELP (Code Excited Linear Predictive Coding)

The Full Rate coding mode is called RPE-LTP (Regular Pulse Excited-Long Term Prediction).

The Half Rate coding mode is called VSELP (Vector-Sum Excited Linear Prediction)

13kbit/s260 bits(FR)

112 bits(HR)

244 bits(EFR) 12.2kbit/s

5.6kbit/s

(A/D)

20 ms

8KHz,13bit

Segmentation Speech coding

Voice


Channel Coding

13kbit/s260 bits(FR)

112 bits(HR)

244 bits(EFR) 12.2kbit/s

5.6kbit/s

(A/D)

20 ms

8KHz,13bit

Segmentation Speech coding

Voice

Channel coding

22.8kbit/s456bits(FR/EFR)228bits(HR) 11.4kbit/s

Block Coder

1:2

Convolutional

Coder


1 2 3 4 5 6 7 8 ... ... 452 453 454 455 4561 2 3 4 5 6 7 8 ... ... 452 453 454 455 456

B

8

16

.

.

.

456

8

16

.

.

.

456

2

10

.

.

.

450

2

10

.

.

.

450

6

14

.

.

.

454

6

14

.

.

.

454

1

9

.

.

.

449

1

9

.

.

.

449

4

12

.

.

.

452

4

12

.

.

.

452

7

15

.

.

.

455

7

15

.

.

.

455

3

11

.

.

.

451

3

11

.

.

.

451

5

13

.

.

.

453

5

13

.

.

.

453

.... ....

B0 B1 B2 B3 B4 B5 B6 B7

{A4,B0} {A5,B1} {A6,B2} {A7,B3} {B4,C0} {B5,C1} {B6,C2} {B7,C3}{A4,B0} {A5,B1} {A6,B2} {A7,B3} {B4,C0} {B5,C1} {B6,C2} {B7,C3}

First interleaving:

Second interleaving:

Interleaving


Voice Burst

Tail bit

Tail bit

Guard periodDat

aData Training sequence

57 encrypted bits3

bits8.25 bits26 bits1

3bits

57 encrypted bits 1

(A/D)

20 ms

22.8kbit/s

13kbit/s8KHz,13bit

33.8kbit/s

Segmentation Speech coding Channel coding

Interleaving Encryption) Burst formatting Modulation

Transmission

Voice


Voice Signal Processing

33.8 kbit/s

22.8 kbit/s

13 kbit/s

8 kHz13 bits

Transmitting part

Receiving part

Speaker

ReceiverDemodulator

Adaptive Equalization

De-cipheringDe-interleaving

Channel decoding

Speech decoding

D/A-conversion

TransmitterModulator

Burst formattingCiphering

Interleaving

Channel coding

Speech codingSegmentation

A/D-conversion

Microphone

13 kbit/s

Transmitting part

Receiving part

TransmitterModulator

Burst formattingCiphering

Interleaving

Channel coding

D/D-conversion

8 kHz8 bits64 kbit/s PCM

ReceiverDemodulator

Adaptive Equalization

De-cipheringDe-interleaving

Channel Decoding

GSM Network

Mobile equipment


Transmission delay t

Transmission delay t

TA

The mobile phone should

send the signal in advance!!

Timing Advance (TA)


Frequency HoppingFrequency

f 0

Frame

f 1

f 2

f 3

f 4

Time


Prolong battery life and reduce interference

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.


Power 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

BCCH Carrier is not involved in power control.

Time

Signal level

Target level value:e.g. -85 dm


Contents

1. Overview


3. Radio Channel


Frequency

200kHz

15/26ms

BPSlot

Time

Frame and Channel


32107654321

Physical Channel and Logical Channel

0

differentmessage

types

Logical channel

Physical Channel

Logical channel

Logical channel

Logical channel

Logical channel

TDMA FRAME

200K

577 ms


8bit 41 synchronous bits

36 encrypted bits

3bit 68.25bit

Tail bit Tail bit Guard intervalData

Guard interval

3bit 142bit 3bit 8.25bit

Tail bit Tail bitData

3bit 39 encrypted bits

39 encrypted bits

3bit 8.25bit

Tail bit Tail bit Guard intervalDataData

Burst

64 synchronous bits

• Access burst (AB): Used in MS initial access

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

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


3bit 142 modulation bits 3bit 8.25bit

Tail bit Tail bit Guard interval

Burst

3bit 57 encrypted bits 57 encrypted bits 3bit 8.25bit

Tail bit Tail bit Guard intervalDataData

26bit1 1

Training sequence

Frame stealing flag

Normal burst (NB)

Used to carry the information of the traffic channel and the control channel

except for RACH

Dummy burst (DB)

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

information delivered


Broadcast control channel (BCH)

Control channelCommon control channel (CCCH)

Voice channel(TCH)

FCCH SCH BCCH TCH/FAGCH RACH SDCCH FACCH

SACCH

TCH/HPCH

Common channel (CCH)

Dedicated channel (DCH)

Logical channel

Logical Channel Type

GSM900 and DCS1800 have the same logical channel

category

(system information)


FCCH

SCH

BCCH

PCH

AGCH

BCCH

CCCH

Common Channel

SDCCH

SACCH

FACCH

TCH/F

TCH/H

DCCH

TCH

Dedicated Channel

Downlink Logical Channel


RACH CCCH

Common channel

SDCCH

SACCH

FACCH

TCH/F

TCH/H

DCCH

TCH

Dedicated channel

Uplink Logical Channel


Use of Logical Channels

FCCH

Allocate signaling channel

Power-on Search for frequency correction burst

Search for synchronous burst

Listen to the system information

Monitor paging message

Send access burst

Set up the call

Allocate voice channel

Conversation

Release the call

Idle mode

SCH

BCCH

PCH

RACH

AGCH

SDCCH

SDCCH

TCH

FACCH

Dedicated mode

Idle mode


26-frame multi-frameTCH/F+FACCH/F+SACCH/F (full-rate TCH)

TCH/H+FACCH/H+SACCH/H (half-rate TCH)

51-frames multi-frameFCCH+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)

Physical Combination of Logical Channel


Structure of Main BCCH1 multi-frame (51TDMA Frames) 235.38ms Downlink

Group Group1 Group2

Group3,

4

(same

as

Group2)

Grpup5

Channel F S BX4 CX4 F S CX4 CX4 …… F S CX4 CX4 I

Frame

Numbe

r

0 1 2-5 6-9 101

1

12-

15

16-

1920-39

4

0

4

1

42-

45

46-

49501 multi-frame (51TDMA Frames) 235.38ms Uplink

Channe

lR R R R R R R R R R R R R R……R R R R R

Frame

Numbe

r

0 1 2 3 4 5 6 7 8 9 10 11 12 13-46 474

8

4

9

5

0

F:FCCH; S:SCH; B:BCCH; C:CCCH; R:RACH; I:IDLE


Structure of Combined BCCH1 multi-frame (51TDMA Frames) 235.38ms Downlink

Group Group1 Group2 Group3 Group4 Grpup5

Channel F S

B

×

4

C

×

4

F S

C

×

4

C

×

4

F S

D

0

×

4

D

1

×

4

F S

D

2

×

4

D

3

×

4

F S

A0

×

4

A1

×

4

I

Channel F S

B

×

4

C

×

4

F S

C

×

4

C

×

4

F S

D

0

×

4

D

1

×

4

F S

D

2

×

4

D

3

×

4

F S

A2

×

4

A3

×

4

I

Frame

Number0 1

2-

5

6-

910 11

12

-

15

16

-

19

20 21

22

-

25

26

-

29

30 31

32

-

35

36

-

39

40 41

42

-

45

46

-

49


Channel D3×4 R R A2×4 A3×4 R……R D0×4 D1×4 R R D2×4

Channel D0×4 R R A0×4 A1×4 R……R D0×4 D1×4 R R D2×4

Frame

Number0-3 4 5 6-9 10-13 14-36 37-40 41-44 45 46 47-50

F:FCCH; S:SCH; B:BCCH; C:CCCH; D:SDCCH ;A:SACCH; R:RACH; I:IDLE


Structure of Logical Channel Combination Frame-Main SDCCH

1 multi-frame (51TDMA Frames) 235.38ms Downlink

ChannelD0

×4

D1

×4

D2

×4

D3

×4

D4

×4

D5

×4

D6

×4

D7

×4

A0

×4

A1

×4

A2

×4

A3

×4I I I

ChannelD0

×4

D1

×4

D2

×4

D3

×4

D4

×4

D5

×4

D6

×4

D7

×4

A4

×4

A5

×4

A6

×4

A7

×4I I I

Frame

Number0-3 4-7

8-

11

12-

15

16-

19

20-

23

24-

27

28-

31

32-

35

36-

39

40-

43

44-

47

4

8

4

9

5

0


ChannelA5

×4

A6

×4

A7

×4I I I

D0

×4

D1

×4

D2

×4

D3

×4

D4

×4

D5

×4

D6

×4

D7

×4

A0

×4

ChannelA1

×4

A2

×4

A3

×4I I I

D0

×4

D1

×4

D2

×4

D3

×4

D4

×4

D5

×4

D6

×4

D7

×4

A4

×4

Frame

Number0-3 4-7

8-

1112 13 14

15-

18

19

-

22

23-

26

27-

30

31-

34

35-

38

39-

42

43-

46

47-

50

D:SDCCH; A:SACCH; I:IDLE


Structure of Logical Channel Combination Frame-TCH

T:TCH;A:SACCH; I:IDLE

1 multi-frame (26TDMA Frames) 120ms

Channel T T T T T T T…T A T,,,T T T T T T T I

Frame

Number0 1 2 3 4 5

6…

1112

13…

1819 20 21 22 23 24 25

1 multi-frame (26TDMA Frames) 120ms

Channel T t T t T t T…t A T,,,t T t T t T t a

Frame

Number0 1 2 3 4 5

6…

1112

13…

1819 20 21 22 23 24 25

Case of one full rate TCH

Case of two half rate TCHs


0 1 2 3 2044 2045 2046 2047

0 1 2 3 48 49 5047

0 1 24 25

0 1 24 25 1 49 500

0 1 4 5 762 3

TB3

TB3

GP8.25

TB: Tail bitTB3

TB3

GP8.25

GP: Guard periodTB3

TB3

GP8.25

TB3

TB3 GP 68.25

58 information bits26 training sequences 58 information bits

Constant bit 142

Information bit 39 Extended training sequence 64 Information bit 39

Synchronous sequence 41 Information bit 36

Normal burst (NB)

Frequency correction burst (FB)

Synchronous burst (SB)

Access burst (AB)

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

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

1 multiframe=26TDMA frames (120ms) 1 multiframe=51TDMA frames (3060/13ms)

1TDMA frame=8 timeslots (120/26=4.615ms)

1 timeslot=156.25 bit duration (15/26=0.577ms)(1 bit duration: 48/13=3.68us)

BCCHCCCHSDCCH

TCHSACCH/TFACCH

Frame


PCH RACHAGCH

Downlink CCCH Uplink CCCH

How to determine the total CCCH resources of the cell? How to

allocate AGCH and PCH reasonably?

Configuration of Common Control Channel


Summary

In this course, we have learned:

Processing of Voice Signal

Radio Channel in Um Interface

Key Technical in Um Interface

Thank youwww.huawei.com

Documents

Gsm Radio Interface Issue2.22 e&s[1]