87641292 OMF000001 Um Interface and Radio Channels ISSUE2 1

8/18/2019 87641292 OMF000001 Um Interface and Radio Channels ISSUE2 1

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Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

Um Interface andRadio Channels



Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page2

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)

Radio resources management (RR)

Mobility and security management

(MM)

Integrated management

TCH0 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

Power

Power

Power

FDMA

TDMA

CDMA

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/s 8KHz,13bi

t

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 LinearPredictive Coding )

The Full Rate coding mode is called RPE-LTP (Regular Pulse Excited-Long

Term Prediction).

The Half Rate coding mode is called VCELP (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,13bi

t

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

BlockCoder

1:2

Convolutional

Coder




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

B

8

16.

.

.

456

2

10.

.

.

450

6

14.

.

.

454

1

9.

.

.

449

4

12.

.

.

452

7

15.

.

.

455

3

11.

.

.

451

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}

First interleaving:

Second interleaving:

Interleaving




Voice Burst

Tailbit

Tailbit

Guard

periodData

Data Training sequence

57 encrypted bits 3

bits 8.25 bits 26 bits 1

3

bits57 encrypted bits 1

(A/D)

20 ms

22.8kbit/s

13kbit/

s 8KHz,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 kHz

13 bits

Transmitting part

Receiving part

Speaker

Receiver

Demodulator

AdaptiveEqualization

De-ciphering

De-interleaving

Channel decoding

Speech decoding

D/A-conversion

Transmitter

Modulator

Burst formatting

Ciphering

Interleaving

Channel coding

Speech coding

Segmentation

A/D-conversion

Microphone

13 kbit/s

Transmitting part

Receiving part

Transmitter Modulator

Burst formatting

Ciphering

Interleaving

Channel coding

D/D-conversion

8 kHz

8 bits

64 kbit/s PCM

Receiver Demodulator

AdaptiveEqualization

De-ciphering

De-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 Hopping

Frequency

f 0

Frame

f 1

f 2

f 3

f 4

Time




Prolong battery life andreduce 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 notinvolved in power control.

Time

Signal level

Target level value:e.g. -85 dm




Contents

1. Overview


3. Radio Channel




Frequency

200kHz

15/26ms

BP

Slit

Time

Frame and Channel




32107654321

Physical Channel of Logical Channel

0

different

message

types

Logical channel

Physical Channel

Logical channel

Logical channel

Logical channel

Logical channel

TDMA FRAME

200K

577 s




8bit 41 synchronous

bits

36 encrypted

bits3bit 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

bits3bit 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 synchronizationbetween 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

3bit57 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 noinformation 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-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)

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

Number0 1 2-5 6-9 10 11 12-15 16-19 20-39 40 41 42-45 46-49 50

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

Channel R R R R R R R R R R R R R R……R R R R R

Frame

Number0 1 2 3 4 5 6 7 8 9 10 11 12 13-46 47 48 49 50

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

D0

4

D1

4

F S

D2

4

D3

4

F S

A0

4

A1

4

I

Channel F S

B

4

C

4

F S

C

4

C

4

F S

D0

4

D1

4

F S

D2

4

D3

4

F S

A2

4

A3

4

I

Frame

Number0 1 2-5 6-9 10 11

12-

15

16-

1920 21

22-

25

26-

2930 31

32-

35

36-

3940 41

42-

45

46-

4950


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 SDCCH1 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

Number 0-3 4-7 8-11

12-

15

16-

19

20-

23

24-

27

28-

31

32-

35

36-

39

40-

43

44-

47 48 49 50


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

Channel A1 4

A2 4

A3 4

I 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 8-11 12 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

Number 0 1 2 3 4 5 6…11 12 13…18 19 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…11 12 13…18 19 20 21 22 23 24 25

Case of one full rate TCH

Case of two half rate TCHs




0 1 2 32044

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

TB

3

TB

3

GP

8.25TB: Tail bitTB

3TB3

GP8.25

GP: Guard periodTB3

TB3

GP8.25

TB3

TB3

GP 68.25

58 information bits26 training

sequences58 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

87641292 OMF000001 Um Interface and Radio Channels ISSUE2 1