Mobile communication and computing gsm-radio-interface-140720014203-phpapp02.pdf

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Copyright © 2010 Huawei Technologies Co., Ltd. All rights reserved.
Um Interface and
Radio Channels

Copyright © 2010 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)
Communication management (CM)
Radio resources management (RR)
Radio resources management (RR)
Mobility and security management
(MM)
Mobility and security management
(MM)
Integrated management
Integrated management
TCH0 TCH1 TCH2 。。 SACCH 。。 TCH23 IDL
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
CC, SS, SMS
Use LAPDm Protocol

Radio Access Technology
Frequency
Time
Power
Frequency
Time
Power
Frequency
Time
Power
FDMA
FDMA
TDMA
TDMA
CDMA
CDMA
User
User
User
User
User
User
User
User
Time
FDMA
Frequency
TDMA
Time
Frequency
CDMA
Frequency
Time
Code

Contents
1. Overview
3. Radio Channel

Voice Signal Processing
(
(A/D
A/D)
)
20
20 ms
ms
22.8kbit/s
22.8kbit/s
13kbit/s
13kbit/s
8KHz,13bi
8KHz,13bi
t
t
33.8kbit/s
33.8kbit/s
Segmentation
Segmentation Speech coding
Speech coding Channel coding
Channel coding
Interleaving
Interleaving Encryption
Encryption)
) Burst formatting Modulation
Modulation
Transmission
Voice

Analog-Digital Conversion

Speech Coding
 The Enhance Full Rate
Enhance Full Rate coding mode is called CELP
CELP (Code Excited Linear
Code Excited Linear
Predictive Coding
Predictive Coding)
 The Full Rate
Full Rate coding mode is called RPE-LTP
RPE-LTP (Regular Pulse Excited-Long
Regular Pulse Excited-Long
Term Prediction).
Term Prediction).
 The Half Rate
Half Rate coding mode is called VCELP
VCELP (
(Vector-Sum Excited Linear
Vector-Sum Excited Linear
Prediction
Prediction)
)
13kbit/s
13kbit/s
260 bits(FR)
260 bits(FR)
112 bits(HR)
112 bits(HR)
244 bits(EFR)
244 bits(EFR) 12.2kbit/s
12.2kbit/s
5.6kbit/s
5.6kbit/s
(
(A/D
A/D)
)
20
20 ms
ms
8KHz,13bi
8KHz,13bi
t
t
Segmentation
Speech coding
Voice

Channel Coding
13kbit/s
13kbit/s
260 bits(FR)
260 bits(FR)
112 bits(HR)
112 bits(HR)
244 bits(EFR)
244 bits(EFR) 12.2kbit/s
12.2kbit/s
5.6kbit/s
5.6kbit/s
(
(A/D
A/D)
)
20
20 ms
ms
8KHz,13bi
8KHz,13bi
t
t
Segmentation
Speech coding
Voice
Channel coding
Channel coding
22.8kbit/s
22.8kbit/s
456bits(FR/EFR)
456bits(FR/EFR)
228bits(HR)
228bits(HR) 11.4kbit/s
11.4kbit/s
Block
Coder
1:2
Convolutional
Coder

1 2 3 4 5 6 7 8 ... ... 452 453 454 455 456
1 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
Tail
bit
bit
Tail
Tail
bit
bit
Guard
Guard
period
period
Dat
Dat
a
a
Data
Data Training sequence
Training sequence
57 encrypted bits
57 encrypted bits
3
3
bits
bits
8.25 bits
8.25 bits
26 bits
26 bits
1
3
3
bits
bits
57 encrypted bits
57 encrypted bits 1
(
(A/D
A/D)
)
20
20 ms
ms
22.8kbit/s
22.8kbit/s
13kbit/
13kbit/
s
s
8KHz,13bit
8KHz,13bit
33.8kbit/
33.8kbit/
s
s
Segmentation
Speech coding Channel coding
Channel coding
Interleaving
Interleaving Encryption
Encryption)
) Burst formatting Modulation
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
Adaptive
Equalization
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
Adaptive
Equalization
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)
TA = 0 to 63
1 bit equivalent to 3.7μs
TS has 156bit
Max coverage = 35Km

Frequency Hopping
Frequency
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.
Sub & Full
Measurement

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
BP
Slot
Time
Frame and Channel

3
2
1
0
7
6
5
4
3
2
1
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 µs

8bit 41 synchronous
bits
36 encrypted
bits
3bit 68.25bit
Tail bit Tail bit Guard interval
Data
Guard interval
3bit 142bit 3bit 8.25bit
Tail bit Tail bit
Data
3bit 39 encrypted
bits
39 encrypted
bits
3bit 8.25bit
Data
Data
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
63bit TA come from
here

3bit 142 modulation bits 3bit 8.25bit
Burst
3bit 57 encrypted bits 57 encrypted bits 3bit 8.25bit
Data
Data
26bit
1 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
Burst rate come from
=156.25/(0.577*8)

Broadcast control channel
(BCH)
Control channel
Common control channel
(CCCH)
Voice channel
(TCH)
FCCH SCH BCCH TCH/F
AGCH RACH SDCCH FACCH
SACCH
TCH/H
PCH
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
TS 2, 4, 6

Structure of Main BCCH
1 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
Number
0 1 2-5 6-9 10
1
1
12-
15
16-
19
20-39
4
0
4
1
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
Number
0 1 2 3 4 5 6 7 8 9 10 11 12 13-46 47
4
8
4
9
5
0
F:FCCH; S:SCH; B:BCCH; C:CCCH; R:RACH; I:IDLE

Structure of Combined BCCH
Group Group1 Group2 Group3 Group4 Grpup5
Channel F S
B×
4
C×
4
F S
C×
4
C×
4
F S
D0
×4
D
1×
4
F S
D2
×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
D0
×4
D
1×
4
F S
D2
×4
D
3×
4
F S
A2
×4
A3
×4
I
Frame
Number
0 1
2-
5
6-
9
10 11
12
-
15
16
-
19
20 21
22
-
25
26
-
29
30 31
32
-
35
36
-
39
40 41
42
-
45
46
-
49
50
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
Number
0-3 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
Channel
D0×
4
D1×
4
D2×
4
D3×
4
D4×
4
D5×
4
D6×
4
D7×
4
A0×
4
A1×
4
A2×
4
A3×
4
I I I
Channel
D0×
4
D1×
4
D2×
4
D3×
4
D4×
4
D5×
4
D6×
4
D7×
4
A4×
4
A5×
4
A6×
4
A7×
4
I 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
4
8
4
9
5
0
Channel
A5
×4
A6×
4
A7×
4
I 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
Number
0-3 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
Number
0 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
DTX
Frame 52nd
to 59th

0 1 2 3 2044 2045 2046 2047
0 1 2 3 48 49 50
47
0 1 24 25
0 1 24 25 1 49 50
0
0 1 4 5 7
6
2 3
TB
3
TB
3
GP
8.25
TB: Tail bit
TB
3
TB
3
GP
8.25
GP: Guard period
TB
3
TB
3
GP
8.25
TB
3
TB
3 GP 68.25
58 information bits
26 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)
BCCH
CCCH
SDCCH
TCH
SACCH/T
FACCH
Frame

PCH RACH
AGCH
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

Mobile communication and computing gsm-radio-interface-140720014203-phpapp02.pdf

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