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Um Interface and Radio Channels

1.

Um Interface and
Radio Channels
www.huawei.com
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

2.

Contents
1. Overview
2. Processing of Voice Signal
3. Radio Channel
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page2

3.

Radio Interface
Another MSC
PSTN
ISDN
BTS
BSC
MS
A-bis
A
MSC/VLR
HLR/AUC
MS
Um
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
SMC
OMC
Page3

Hierarchical Structure of Um Interface
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page4
FACCH

5.

Radio Access Technology
CDMA
Time
CDMA
Power
Code
Frequency
TDMA
Time TDMA
Power
Frequency
FDMA
Power
Time
FDMA
Frequency
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page5

6.

Contents
1. Overview
2. Processing of Voice Signal
3. Radio Channel
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page7

7.

Voice Signal Processing
8KHz,13bi
t
13kbit/s
20 ms
Voice
(A/D)
Segmentation
Speech coding
Channel coding
22.8kbit/s
33.8kbit/s
Interleaving
Encryption)
Burst formatting
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Modulation
Page8
Transmission

8.

Analog-Digital Conversion
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page9

9.

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 VCELP (Vector-Sum Excited Linear
Prediction)
8KHz,13bi
t
20 ms
244 bits(EFR)
260 bits(FR)
112 bits(HR)
Voice
Segmentation
Speech coding
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page10
(A/D)
12.2kbit/s
13kbit/s
5.6kbit/s

10.

Channel 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)
Segmentation
Speech coding
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Channel coding
Page11

11.

Interleaving
B
1 2 3 4 5 6 7 8 ...
First interleaving:
....
... 452 453 454 455 456
B0
B1
B2
B3
B4
B5
B6
B7
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
449
450
451
452
453
454
455
456
....
Second interleaving:
{A4,B0}
{A5,B1}
{A6,B2}
{A7,B3}
{B4,C0}
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
{B5,C1}
{B6,C2}
Page12
{B7,C3}

12.

Voice Burst
Tail
bit
3
bits
Training sequence
Data
57 encrypted bits
8KHz,13bit
Voice
(A/D)
1
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)
Burst formatting
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Transmission
Modulation
Page14

13.

Voice Signal Processing
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
Receiver
Demodulator
Transmitter
Modulator
Adaptive
Equalization
Adaptive
Equalization
De-ciphering
De-interleaving
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page15

14.

15.

16.

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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page20

17.

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
Signal level
Target level value:
e.g. -85 dm
BCCH Carrier is not
involved in power control.
Time
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page22

18.

19.

20.

Physical Channel of Logical Channel
TDMA FRAME
0
1
2
3
4
5
6
7
0
1
2
3
200K
577 ms
Physical Channel
Logical channel
Logical channel
different
message
types
Logical channel
Logical channel
Logical channel
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page25

21.

Burst
• 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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Data
Tail bit Guard interval
39 encrypted
3bit 8.25bit
bits
Page26

22.

Burst
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
3bit
142 modulation bits
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page27
8.25bit

23.

Logical Channel 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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page28
TCH/F
TCH/H

24.

Downlink Logical Channel
FCCH
Common
Channel
BCCH
SCH
BCCH
CCCH
PCH
AGCH
SDCCH
Dedicated
Channel
DCCH
SACCH
FACCH
TCH
TCH/F
TCH/H
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page29

25.

26.

Use of Logical Channels
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
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page33

27.

Physical Combination of Logical Channel
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)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page34

28.

Structure of Main BCCH
1 multi-frame (51TDMA Frames) 235.38ms Downlink
Group3,4
Group
Group1
Group2
(same as
Grpup5
Group2)
Channel
Frame
F
S
BX4
CX4
F
S
CX4
CX4
……
F
S
CX4
CX4
I
0
1
2-5
6-9
10
11
12-15
16-19
20-39
40
41
42-45
46-49
50
Number
1 multi-frame (51TDMA Frames) 235.38ms Uplink
Channel
Frame
R
R
R
R
R
R
R
R
R
R
R
R
R
R……R
R
R
R
R
0
1
2
3
4
5
6
7
8
9
10
11
12
13-46
47
48
49
50
Number
F:FCCH; S:SCH; B:BCCH; C:CCCH; R:RACH; I:IDLE
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page35

29.

Structure of Combined BCCH
1 multi-frame (51TDMA Frames) 235.38ms Downlink
Group
Group1
Channel
F
Channel
F
Frame
0
Number
C
×
×
4
4
B
C
×
×
4
4
2-5
6-9
S
B
C
×
×
4
Group3
C
S
1
Group2
F
F
10
S
S
11
Group4
D0
D1
×
×
4
4
C
C
×
×
4
4
12-
16-
15
19
F
F
20
S
S
21
Grpup5
D2
D3
×
×
4
4
D0
D1
×
×
4
4
22-
26-
25
29
F
F
30
1 multi-frame (51TDMA Frames) 235.38ms
S
S
31
A0
A1
×
×
4
4
4
D2
D3
A2
A3
×
×
×
×
4
4
4
4
32-
36-
42-
46-
35
39
45
49
F
S
F
S
40
41
I
I
50
Uplink
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
0-3
4
5
6-9
10-13
14-36
37-40
41-44
45
46
47-50
Frame
Number
F:FCCH; S:SCH; B:BCCH; C:CCCH; D:SDCCH ;A:SACCH; R:RACH; I:IDLE
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page36

30.

Structure of Logical Channel
Combination Frame-Main SDCCH
1 multi-frame (51TDMA Frames) 235.38ms Downlink
Channel
Channel
Frame
Number
D0
D1
D2
D3
D4
D5
D6
D7
A0
A1
A2
A3
×4
×4
×4
×4
×4
×4
×4
×4
×4
×4
×4
×4
D0
D1
D2
D3
D4
D5
D6
D7
A4
A5
A6
A7
×4
×4
×4
×4
×4
×4
×4
×4
×4
×4
×4
×4
0-3
4-7
8-11
12-
16-
20-
24-
28-
32-
36-
40-
44-
15
19
23
27
31
35
39
43
47
I
I
I
I
I
I
48
49
50
1 multi-frame (51TDMA Frames) 235.38ms Uplink
Channel
Channel
Frame
Number
A5
A6
A7
×4
×4
×4
A1
A2
A3
×4
×4
×4
0-3
4-7
8-11
I
I
I
I
I
I
12
13
14
D0
D1
D2
D3
D4
D5
D6
D7
A0
×4
×4
×4
×4
×4
×4
×4
×4
×4
D0
D1
D2
D3
D4
D5
D6
D7
A4
×4
×4
×4
×4
×4
×4
×4
×4
×4
15-
19-
23-
27-
31-
35-
39-
43-
47-
18
22
26
30
34
38
42
46
50
D:SDCCH; A:SACCH; I:IDLE
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page37

31.

Structure of Logical Channel
Combination Frame-TCH
Case of one full rate TCH
1 multi-frame (26TDMA Frames) 120ms
Channel
Frame
Number
T
T
T
T
T
T
T…T
A
T,,,T
T
T
T
T
T
T
I
0
1
2
3
4
5
6…11
12
13…18
19
20
21
22
23
24
25
Case of two half rate TCHs
1 multi-frame (26TDMA Frames) 120ms
Channel
Frame
Number
T
t
T
t
T
t
T…t
A
T,,,t
T
t
T
t
T
t
a
0
1
2
3
4
5
6…11
12
13…18
19
20
21
22
23
24
25
T:TCH;A:SACCH; I:IDLE
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page38

32.

Frame
1 hyper frame=2048 super-frames=2715648TDMA frames (3 hours, 28 minutes, 53 seconds and 760 milliseconds)
0
TCH
SACCH/T
FACCH
1
2
3
2045
2044
2046
1 super-frame=1326TDMA frames (6.12 seconds)
1
0
0
2
3
47
1
0
1
1
49
24
1 multiframe=26TDMA frames (120ms)
0
48
24
50
2047
BCCH
CCCH
SDCCH
25
1 multiframe=51TDMA frames (3060/13ms)
25
0
1TDMA frame=8 timeslots (120/26=4.615ms)
2
3
4
5
6
1
49
7
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)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
50
58 information bits
Information bit 39
GP 68.25
Page39
TB
3
TB
3
GP
8.25
GP
8.25
TB GP
3 8.25
TB: Tail bit
GP: Guard period