technologie komunikacji bezprzewodowej” „technologia...

Projekt wspó finansowany przez Uni Europejsk w ramach Europejskiego Funduszu Spo ecznego

1

„Technologie komunikacji bezprzewodowej”„Technologia GSM”

Prezentacja jest wspó finansowana przez Uni Europejsk w ramach

Europejskiego Funduszu Spo ecznego w projekcie pt.„Innowacyjna dydaktyka bez ogranicze - zintegrowany rozwój Politechniki ódzkiej -

zarz dzanie Uczelni , nowoczesna oferta edukacyjna i wzmacniania zdolno ci do zatrudniania osób niepe nosprawnych”

Prezentacja dystrybuowana jest bezp atnie

Politechnika ódzka, ul. eromskiego 116, 90-924 ód , tel. (042) 631 28 83www.kapitalludzki.p.lodz.pl


GSM Overview

Rafa Watza, DOTREricpol Telecom Sp. z [email protected].: +48 663 487959


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• GSM History and services

• GSM Structure

• Radio Interface

• Channels and Bursts

• ID - Numbers

• Traffic Cases

Agenda


4

GSM History


5

NMT

1981 1983

NMT - Nordic Mobile TelephoneAMPS - Advanced Mobile Phone Service

AMPS

TACS - Total Access Communication SystemJTACS - Japanese TACS

Early cellular systems


6

GSM is born

1982 – Purpose of developing new cellular standard

1986 – Radio transmission chosen

1987 – Groupe Speciale Mobile MoU charter signed

1989 – GSM as ETSI standard defined

1991 – Oy Radiolinja – first GSM Operator

f [MHz]

GSM 900

890 960

GSM 1800

1710 1880

UMTS

1920 2170

NMT

425 490

1850 1910

GSM 1900


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Basic• allow subscribers to send and receive different types of info

Supplementary• services activated on request

Bearer Services• traffic channel

Teleservices• sending telecommunication data over traffic channel

End to End call

Bearer Channel

GSM Services


8

Time91/92 98 99/00 02

P1P2

R96

R97

R4R5

R99R98

R9

03 07 08 0904/05

R6R7

R8

Functionality

GSM ReleasesIDEA Standardization Usage

Network evolution


9

• Speech call

• Managing mobility

• SMS service

• Call barring

• Basic fax/data services

• Ciphering data

GSM Phase 1 Services


10

• Calling line identification

• Conference calling

• Call holding / waiting

• GSM900 – GSM1800 roaming

• EFR Speech codec

• SMS concatenation

GSM Phase 2 Services


11

• Access to ISP in GPRS Phase 2

• Charging and billing for GPRS

• Architecture of GSM-UMTS platform

• Service provider number portability

• IP-in-IP tunneling for GPRS

• Noise suppression for Adaptive Multi Rate speech codec

• UMTS support

• Location services (LCS)

GSM Release 99 Services


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• Release 4

• Layered architecture MSC Server-Media Gateway

• Release 5

• RAN improvements

• GERAN support for IMS

• AMR WB

• Release 6

•Multimedia Broadcast and Multicast service

• AMR WB +

• Support of PS handover (A/Gb interface)


13

GSM Structure


14

GSM Networ

k

PSTNISDN

INTERNET

How GSM Network is built?MS consists of:

• Equipment

• SIM Card

+48 400 100200

Air Interface vs. Cable


15

BTS

BTS

PSTN

ISDN

PLMPLMN

INTERNET Mobile IN

BSC

BTS

SC

GIWU

TRC

BSC/TRC

GMSC

HLR

MSC

VLR

AUC

EIR

NSS BSS

MaintenancMaintenance and

Operation

GSM Structure (2G – Phase1)


16

BTS

BTS

PSTN

ISDN

PLMPLMN

INTERNET

BSC

BTS

AUC

SC

GIWU

TRCGMSC

HLR

GGSN

BSC/TRC

EIR

SGSN

MSC

VLR

NSS BSS

GSM Structure (2.5G – R99)


17

BTS

BTS

PSTN

ISDN

PLMPLMN

INTERNET

BSC

BTS

TRCMGW

HSS

BSC/TRC

UTRAN

MGW

MSS MSS

GGSN

SC EIR

SGSN

NSS BSS

GSM Structure (R4)


18

BTS

BTS - Base Transceiver Station

Cell – area covered by BTS

Cell

Communication with Mobile Station


19

BTS

• Radio transmission

• Radio signal reception

• Signal processing

• Quality measurements

• Synchronization / maintenance

• Broadcasting system information

BSC

Base Transceiver Station


20

Rural environment –

low density

Suburban environment –

average density

Urban environment –high density

Pico cell – highest densityCity boundaries

Coverage optimisation


21

BSC – Base Station Controller

BSS – Base Station System

BTS

BTS

BSC

BTS

TRC

BSC/TRC

BSS

TRC – Transcoder

TRAU – Transcoder and Rate Adaptation Unit

• Provides bitrate transcoding from 13 kbps -> 16 kbps and 16x4 -> 64 kbps

How to control BTSs and MSs


22

TRC

BSC

BTS

• Radio network management

• BTS administration and control

• Traffic measurements

• Connections handling

• Software handling

Base Station Controller


23

MSC Service Area

MSC – Mobile service Switching Centre

LA – Location Area

BTS

BTS

BSC

BTS

TRC

BSC/TRCBSC/TRC BTS

BTS

BTS

BTS

BTS

MSC

MSC BSCTRC BTS

LA2

LA1LA14

LA3

Network Switching System


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• Setting up and controlling calls

• Handling speech path continuity for moving subscribers

• Updating mobile subscriber data

• Receiving and delivering short messages

• Charging

TRC

MSC

GMSC

Mobile services Switching Centre


25

GMSC – Gateway MSC

PSTN – Public Switched Telephone Network

PLMN – Public Land Mobile Network

ISDN – Integrated Services Digital Network

BTS

BTS

PSTN

ISDN

PLMPLMN BSC

BTS

TRCGMSC

BSC/TRC

MSC

Connection to other networks


26

PSTN

PSTN

ISDN

ISDN

MSC

GMSC

PLMNPLMN

• Interface to other networks

• Roaming interrogation

• Call forwarding

Gateway MSC


27

HLR – Home Location Register

BTS

BTS

PSTN

ISDN

PLMPLMN BSC

BTS

TRCGMSC

HLR

BSC/TRC

MSC

Network Subscribers


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Database which stores:

• Subscriptions

• MSISDN number

• IMSI number

• list of services

• VLR/MSC address

• Authentication and ciphering data

MSC

HLR

AuC

GMSC

Home Location Register


29

VLR – Visitor Location Register

BTS

BTS

PSTN

ISDN

PLMPLMN BSC

BTS

TRCGMSC

HLR

BSC/TRC

MSC

VLR

Who is where?


30

MSC

MSC

VLR


• Subscriber location

• Subscriber services (copy from HLR)

• MS status

• Other flags and pointersHLR

VLR

UPDATE

DELETE

Visitor Location Register


31

AuC – Authentication Centre

BTS

BTS

PSTN

ISDN

PLMPLMN BSC

BTS

AUC

TRCGMSC

HLR

BSC/TRC

MSC

VLR

Security


32

Node which generates:

• Subscribers triplets

• RANDom number – RAND

• Signed RESponse – SRES

• Ciphering Key – Kc

HLR

AuC

Authentication Centre


33

RAND

RAND

Ki

SRES Kc

A8A3

IMSI

Triplet

AuC

Triplet Provision


34

A3

MSC

VLR

RAND

SRES

=

Access to network

SRES

Ki

RAND

RAND

IMSI attach

Authentication Procedure


35

EIR– Equipment Identity Register

BTS

BTS

PSTN

ISDN

PLMPLMN BSC

BTS

AUC

TRCGMSC

HLR

BSC/TRC

EIR

MSC

VLR

EIR – Equipment Identity Register


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• IMEI number

• Provides information about

• stolen equipment (black list)

• faulty equipment (grey list)

• unknown equipment

MSC

EIR

Equipment Identity Register


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SC – Service Centre

(SMS-C – Short Message Service Centre)

BTS

BTS

PSTN

ISDN

PLMPLMN BSC

BTS

AUC

SC

TRCGMSC

HLR

BSC/TRC

EIR

MSC

VLR

Short messages


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SGSN – Serving GPRS Support Node

GGSN – Gateway GPRS Support Node

PCU – Packet Control Unit

DTI – Data Transmission Interface

GIWU – GSM Interworking Unit

BTS

BTS

PSTN

ISDN

PLMPLMN

INTERNET

BSC

BTS

AUC

SC

GIWU

TRCGMSC

HLR

GGSN

EIR

SGSN

MSC

VLR DTI

PCU

BSC/TRC

Data transmission

PLMN


39

Radio Interface


40

ONE FREQUENCY – ONE STATION

FDMA – Frequency Division Multiple Access

f1

f2

How the radio works?


41

BTS

TDMA – Time Division Multiple Access

ONE FREQUENCY – MANY CALLS

f1

f1

TDMA Solution for GSM


42

BTS

BTS

f1f1

?

Solution – Frequency Reuse

BTS

f1

f2

Interferences

Coverage Problem


43

2

1

1

3

23

21

21

2

13

32

612

3

1

8

102

5

4

10

7

311

106

4

2

1151

75

612

11

8

1

8

9

3

124

7

92

3

6

1

9

9

65

2

4

3

11

2

34

63

24

5

7

716

27

16

4

5 1

5

3

24

1

65

7

3

1

4

7

41

2

2

3

12

4

43

21

4

2

1

34

41

1

3 32

14

3

32

2

4

1

3

3

Frequency Reuse Factor


44

I1 N1 F1 O1 I2 N2 F2 O2 I3 N3 F3 O3

BTS

X X X O1 I2 N2 F2 O2 I3 N3 F3 O3

I1 I2 I3 N1 N2 N3 F1 F2 F3 O1 O2 O3

I1 I2 I3N1 N2 N3F1 F2 F3O1 O2 O3I1 N1 F1 O1 I2 N2 F2 O2 I3 N3 F3 O3

I I IX X X N1 N2 N3 F1 F2 F3 O1 O2 O3

X N1 F1 O1X N2 F2 O2X N3 F3 O3

Interleaving and errors


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• Shadowing

• Rayleigh

BTS

Fading Problem


46

BTS

f1f2f3

f4

Changing the carrier frequency at frequent intervals

What is the time between hops?

Fading dip

Frequency Hopping


47

Mobile Station is too far away from BTS

BTS

Signal

Strength

Distance

Path Loss


48

BTS

Combined signal power


49

BTSBTS

Another BTS handles the call

DURING THE CALL

Handover


50

BTS

Time

Information does not arrive within allocated time slot

3

434

Time Alignment


51

BTSTA

Time

Information is sent earlier

Possible range: 0 ÷ 233 µs (shift 3,69 µs)

3 3

Timing Advance


52

BTS

Maximum Channel Capacity by C. E. Shannon (Kotelnykov)

Air Link


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0 1 1 1 0 0 0 0 0 0 1 1 1

1. Sampling

2. Quantization

3. Coding

8kHz

8192 levels

13bits

A/D Conversion in GSM


54

20ms20ms20ms20ms

x samples * 13bits

Segmentation


55

260 bits

010001000100100100100010000011111001010000101000101110101010010110

20ms20ms20ms20ms

Speech Coding


56

78 NSIB

4 Tail Bits

50 VIB

132 IB

Block

coder53

1:2

Convolutional

Coder 456 bits

378

VIB – Very Important Bits

IB – Important Bits

NSIB – Not So Important Bits

Channel Coding


57

1

Burst

BER = 25%

57 bits

20

ms

1

0

1

0

13, 11 - - - - - -- - 451

4, 12 - - - - - - - 452

5, 13 - - - - - -- - 453

6, 14 - - - - - -- - 454

7, 15 - - - - - - - 455

8, 16 - - - - - - - 456

02, 10 - - - - - - - 450

11, 9 - - - - - - -- - 449

Interleaving Stage 1


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1

Burst

BER = 12,5%

57 bits

20

ms

120

ms

3, 11 - - - - - - - 451

4, 12 - - - - - - - 452

02, 10 - - - - - - - 450

11, 9 - - - - - - - - 449

8, 16 - - - - - - - 456

7, 15 - - - - - - - 455

6, 14 - - - - - - - 454

5, 13 - - - - - - - 453

Interleaving Stage 2


59

A5

1 1 1

111

Ciphering


60

• Training sequence

• Tail bits (000)

11 1 1 1 1tail tailTrain. Seq.

Burst formatting


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• Placed in the middle of the burst to minimise distance to data bits

• Estimation of the channel for each transmitted signal

• 8 different, uncorrelated sequences are standardized:

Training sequence No. Training sequence bits

1 (1,1,1,1,1,1,0,1,1,1,0,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0)

2 (1,1,1,1,1,1,0,1,1,1,0,1,1,1,1,0,0,0,1,0,1,1,1,1,1,1)

3 (0,0,0,0,0,0,1,1,1,0,1,1,1,0,1,0,0,1,0,0,0,0,0,0,0,0)

4 (1,1,1,1,1,1,1,1,1,0,1,1,0,1,0,0,0,1,0,0,0,0,0,0,0,0)

5 (0,0,0,0,0,0,1,0,1,1,1,0,0,1,0,0,0,0,0,1,1,1,1,1,1,1)

6 (1,1,1,1,1,1,1,0,1,0,1,1,0,0,0,0,0,1,0,0,1,1,1,1,1,1)

7 (1,1,1,1,1,1,1,1,1,1,0,1,1,0,0,0,1,0,1,0,0,0,0,0,0,0)

8 (1,1,1,1,1,1,1,1,0,0,0,1,0,0,1,0,1,1,1,0,1,1,1,1,1,1)

Training sequence – equalization


62

BTS

GMSK

Modulation & Transmission


63

A/D Conversion

Segmentation

Speech coding

Channel coding

Interleaving

Ciphering/encryption

Burst formatting

Modulation & Transmission

Radio Interface Summary


64

Channels and Bursts


65

BTS

Up Link – direction from MS tothe network

Down Link – direction from the network to the MS

Up Link & Down Link


66

890 915 935 960 MHz

P-GSM 900:

Bandwidth – 25MHz

Duplex Distance – 45MHz

E-GSM 900:

Extra 10 MHz bandwidth

EG

SM Up Link

EG

SM Down Link

Channel Concept 1


67

FrequencyFDMA FDMA

ARFCN – Absolute Radio Frequency Channel Number

Carrier separation – 200kHz

P-GSM900 – Radio Channels – 124

1

12

4

21

12

4

2

200 kHz

Channel Concept 2


68

FrequencyFDMAFDMA

TS0TS1

TS2TS3

TS4TS5

TS6TS7

Time slot

TS0TS1

Channel Concept 3


69

Time

TS0TS1

TS2TS3

TS4TS5

TS6TS7

TDMA Frame n n+1 n+2 n+3 n+4 n+5

BPC– Basic Physical Channel

Basic Physical Channel


70

LOGICAL CHANNELS

CONTROL CHANNELS TRAFFIC CHANNELS

Full Rate

Half Rate

Broadcast

Common Control

Dedicated Control

Logical Channels


71

Traffic Channels

• Full Rate (TCH - FR): transmits full rate speech/data

EFR – 15.1kbps

FR – 13 kbps

DATA – 9.6 or 14.4 kbps

• Half Rate (TCH - HR): transmits half rate speech/data

HR – 6.5 kbps

DATA – 4.8 kbpsBTS

How to transfer information


72

Broadcast Channels (BCH)

• Frequency Correction Channel (FCCH)

• Synchronization Channel (SCH)

• Broadcast Control Channel (BCCH)

BTS

How to transfer network info


73

Common Control Channels (CCCH)

• Paging Channel (PCH)

• Random Access Channel (RACH)

• Access Grant Channel (AGCH)

BTS

How to make or receive call


74

Dedicated Control Channels (DCCH)

• Stand alone Dedicated Control Channel (SDCCH)

• Slow Associated Control Channel (SACCH)*

• Fast Associated Control Channel (FACCH)*

• Cell Broadcast Channel (CBCH)

BTS

How to make call set-up


75

Frequency

TS0TS1

TS2TS3

TS4TS5

TS6TS7

Traffic Channels

Dedicated Control

Channels

Broadcast Channel

Common Control Channel

C0 C1 C3C2

Channel Mapping


76

TS0 TS1 TS2 TS3 TS4 TS6TS5 TS7

1 TDMA frame = 8 Timeslots (4,615 ms)

0 1 2 3 22 23 24 25 0 1 2 3 47 48 49 50

1 multiframe = 26 TDMA frames (120 ms) 1 multiframe = 51 TDMA frames (235 ms)

0 1 2 3 4 47 48 49 500 1 2 252423

1 superframe = 1326 TDMA frames (6,12 s)

51 (26-frame) multiframes or 26 (51-frame) multiframes

20472046204520440 1 21 hyperframe = 2048 superframes = 2 715 648 TDMA frames (3h 28min 53s 760ms)

Traffic Signalling

Frames structure


77

Traffic Channels

Dedicated Control

Channels

Broadcast Channel


FrequencyTS0

TS1TS2

TS3TS4

TS5

F

CUL0 CUL1 CDL1

Frame number

CDL0

SBBBBCCCCFSCCCCCCCCFSC…

I

RR

R

RRR

R

51 T

DM

A

fram

es

Channel Mapping


78

Traffic Channels

Dedicated Control

Channels

Broadcast Channel


F S B C F S C F S C F S C F S C I

R R R R R R R R R

Frame number

0 1 6 5022 32

Channel Mapping – TS0


79

FSBBBBCCCC

D0D0D0D0D1D1D1D1D2D2

Traffic Channels

Dedicated Control

Channels

Broadcast Channel


Frame number

Time slot number

TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7

FS

D2D2

C D3C D3C D3C D3C D4C D4C D4C D4F D5S D5C D5C D5C D6C D6C D6C D6

Channel Mapping


80

FR-TCH

HR-TCH (two calls)

T T T T T T T T T T T T A T T T T T T T T T T T T I

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

26 TDMA frames = 120 msMultiframe for xR traffic channels

Full Rate vs Half Rate TCH


81

LOGICAL CHANNELS

Normal Burst Synchr. Burst Access Burst Freq. Corr. Burst

TCH-FR

TCH-HR

BCCH

PCH

AGCH

SDCCH

SACCH

FACCH

SCH FCCH

RACH

TCH

BCH

CCCH

DCCH

Channel Mapping


82

Burst types:

• Normal NB

• Frequency Correction FB

• Synchronization SB

• Access AB

3 TB 57 Encrypted bits 1 flag 26 Train seq 1 flag 57 Encrypted bits 3 TB 8.25 GP

3 TB 142 Fixed bits 3 TB 8.25 GP

3 TB39 Information

bits 64 Synchronization seq.39 Information

bits 3 TB 8.25 GP

8 TB 41 Synchronization seq.36 Information

bits 3 TB 68.25 GP

TB – Tail Bits

GP – Guard Period

TS0 TS1 TS2 TS3 TS4 TS6TS5 TS7

148 bits 30 s

Bursts


83

ID – Numbers


84

SNNDCCCMSISDN

CC National Mobile Number

NDC SN

CC – Country Code

NDC – National Destination Code

SN – Subscriber Number

48 601 123456

Identity Numbers – MSISDN


85

IMSI

MCC MNC MSIN

MCC – Mobile Country Code

MNC – Mobile Network Code

MSIN – Mobile Subscriber Identification Number

MSINMNCMCC

260 03 39508409

International Mobile Subscriber Identity – IMSI


86

TMSI

4 octets

Temporary Mobile Station Identity TMSI


87

IMEI

TAC

TAC – Type Approval Code

FAC – Final Assembly Code

SNR – Serial Number

FAC SNR spare

*#06#

SNRFACTAC

35 0010 xxxxxxxx

International Mobile Equipment Identity IMEI


88

CC – Country Code

NDC – National Destination Code

SN – Servicing Number

MSRN

CC NDC SN

SNNDCCC

48 663 426592

Mobile Station Roaming Number MSRN


89

MSCGMSC

PSTN

ISDN

PLMN

HLR

VLR

MSISDN

MSISDN

IMSI

MSRN

MSRN

MSRN

MSRN IMSI

Call to an MS (MSRN example)


90

MCC – Mobile Country Code

MNC – Mobile Network Code

LAC – Location Area Code

LAI

MCC MNC LAC

LACMNCMCC

260 03 65536

Location Area Identity LAI


91

LAI – Location Area Identity

CI – Cell Identity

CGI

LAI CI

CILAI

2600365536 12345

Cell Global Identity CGI


92

Traffic Cases


93

MSC

HLR

VLR

IMSI Attach is executed when the MS is switched on.

SDCCH Request

IMSI Attach

IMSI Attach ack.

IMSI Attach Ack.

RACH

IMSI AttachSDCCH

SDCCH

SDCCH Assign AGCH

Freq. correction FCCH

Synchronization SCH

Info about BTS BCCH

BTS

BSC/TRC

SDCCHAuthentication and other signalling

IMSI Attach


94

MSC

HLR

VLR

LA1

LA2

MS changes LA within same MSC/VLR

BCCHDifferent LAI

SDCCH Request (Reason Loc. Update)RACH

SDCCH Assign AGCH

SDCCHLocation Updating Request

Location Updating Ack. SDCCH

BSC/TRC

BTS

Location Updating, same MSC/VLR


95

MSC

HLR

BSC/TRC

VLR

MS changes LA to new that belongs to a new MSC/VLR

UPDATE

DELETE

Location Updating Ack.SDCCH

BCCH

RACH

AGCH

SDCCHLocation Updating Request

Different LAI

BTS

MSC

VLR

Location Updating, new MSC/VLR


96

MSC

BTS

GMSC

PSTN

ISDN

PLMN

HLR

AuC EIR

VLR

MSISDN

Route

Paging Message PCH

SDCCH Request RACH

AGCHSDCCH Assign

Paging

Call set-up SDCCH

TCHCALL

BTS

BSC/TRC

Call to MS


97

MSC

BTS

GMSC

PSTN

ISDN

PLMN

HLR

AuC EIR

VLR

SDCCH RequestRACH

AGCH

SDCCH

SDCCH

SDCCH Assign

Call set-up

TCH Assign

TCH

BSC/TRC

Call from MS


98

MSC

BSC/TRC

VLR

BTS measures:

• Signal strength

• Transmission quality on TCH up link

MS measures:

• Signal strength

• Transmission quality on TCH down link

Measurement reports from MS are sent to BTS

Measurement reports from MS and BTS

Decision about handover

BTS

Measurements


99

BTS

MSC

VLR

Handover between two cells controlled by different BSC

Handover Decision

Handover

Required

Handover

RequestActivate TCH

Frequency

Time Slot

Freq. TSFACCH

FACCH

FACCH

FACCH

HO Access B

TA

Handover Complete

MS measurementsMS+BTS

measurements

BTS

BSC/TRC

BSC/TRC

Release TCH

Inter-BSC Handover


100

MSC

VLR

BTS

MSC

VLR

Handover between two cells controlled by different MSC/VLR

Decision

Handover

Required

Handover

Request

Activate TCH

Frequency

Time Slot

Freq. TSFACCH

FACCH

FACCH

FACCH

HO Access B

TA

Handover Complete

MS measurements

MS+BTS measurements

Call Connection Completed

BTS

BSC/TRC

UPDATE

BSC/TRC

Inter-MSC Handover


101

Any questions?


102

Ericpol, DOTREricpol Telecom Sp. z [email protected]: +48 663 487 959

Thank you for your attention.


103

„Technologie komunikacji bezprzewodowej”„Technologia GSM”

Prezentacja jest wspó finansowana przez Uni Europejsk w ramach

Europejskiego Funduszu Spo ecznego w projekcie pt.„Innowacyjna dydaktyka bez ogranicze - zintegrowany rozwój Politechniki ódzkiej -

zarz dzanie Uczelni , nowoczesna oferta edukacyjna i wzmacniania zdolno ci do zatrudniania osób niepe nosprawnych”

Prezentacja dystrybuowana jest bezp atnie

Politechnika ódzka, ul. eromskiego 116, 90-924 ód , tel. (042) 631 28 83www.kapitalludzki.p.lodz.pl

technologie komunikacji bezprzewodowej” „technologia...

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