Technologie komunikacji bezprzewodowej Technologia GSM

Transkrypt

1 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, ód, tel. (042) w ramach Europejskiego Funduszu Spo ecznego

2 GSM Overview Rafa Watza, DOTR Ericpol Telecom Sp. z o.o. Rafal.Watza@ericpol.pl Tel.:

3 Agenda 3 GSM History and services GSM Structure Radio Interface Channels and Bursts ID - Numbers Traffic Cases

4 4 GSM History

5 5 Early cellular systems NMT - Nordic Mobile Telephone AMPS - Advanced Mobile Phone Service TACS JTACS - Total Access Communication System - Japanese TACS NMT AMPS

6 Oy Radiolinja first GSM Operator 1989 GSM as ETSI standard defined 1987 Groupe Speciale Mobile MoU charter signed 1986 Radio transmission chosen 1982 Purpose of developing new cellular standard GSM is born NMT GSM 900 GSM 1800 GSM 1900 UMTS f [MHz]

7 GSM Services 7 Basic allow subscribers to send and receive different types of info Bearer Services traffic channel Teleservices sending telecommunication data over traffic channel Bearer Channel Supplementary End to End call services activated on request

8 Network evolution 8 Functionality IDEA Standardization Usage GSM Releases R7 R8 R9 R5 R6 R4 R96 R97 R98 R99 P1 P2 91/ / / Time

9 GSM Phase 1 Services 9 Speech call Managing mobility SMS service Call barring Basic fax/data services Ciphering data

10 GSM Phase 2 Services 10 Calling line identification Conference calling Call holding / waiting GSM900 GSM1800 roaming EFR Speech codec SMS concatenation

11 GSM Release 99 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)

12 12 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 13 GSM Structure

14 Air Interface vs. Cable 14 MS consists of: How GSM Network is built? Equipment SIM Card GSM Networ k INTERNET PSTN ISDN

15 PSTN GSM Structure (2G Phase1) NSS BSS 15 PLM N GMSC VLR MSC TRC BSC ISDN BSC/TRC AUC GIWU SC EIR HLR Maintenanc e and Operation INTERNE T Mobile IN

16 PSTN GSM Structure (2.5G R99) NSS BSS 16 PLM N GMSC VLR MSC TRC BSC ISDN BSC/TRC GIWU AUC SC EIR HLR INTERNE T GGSN SGSN

17 PSTN GSM Structure (R4) NSS BSS 17 PLM N MGW MGW TRC BSC ISDN MSS MSS BSC/TRC SC EIR HSS INTERNE T GGSN SGSN UTRAN

18 Communication with Mobile Station 18 - Base Transceiver Station Cell area covered by Cell

19 Base Transceiver Station 19 Radio transmission Radio signal reception Signal processing Quality measurements Synchronization / maintenance Broadcasting system information BSC

20 Coverage optimisation 20 Rural environment low density Suburban environment average density City boundaries Urban environment high density Pico cell highest density

21 How to control s and MSs BSS 21 BSC Base Station Controller TRC BSC BSS Base Station System BSC/TRC TRC Transcoder TRAU Transcoder and Rate Adaptation Unit Provides bitrate transcoding from 13 kbps -> 16 kbps and 16x4 -> 64 kbps

22 Base Station Controller 22 Radio network management administration and control Traffic measurements Connections handling Software handling TRC BSC

23 Network Switching System 23 MSC TRC BSC LA3 MSC TRC BSC BSC/TRC BSC/TRC LA1 LA14 LA2 MSC Service Area MSC Mobile service Switching Centre LA Location Area

24 Mobile services Switching Centre 24 Setting up and controlling calls Handling speech path continuity for moving subscribers Updating mobile subscriber data Receiving and delivering short messages Charging GMSC MSC TRC

25 Connection to other networks 25 PSTN PLM N GMSC MSC TRC BSC ISDN BSC/TRC GMSC Gateway MSC PSTN Public Switched Telephone Network PLMN Public Land Mobile Network ISDN Integrated Services Digital Network

26 Gateway MSC 26 Interface to other networks Roaming interrogation Call forwarding PST N PLMN ISD N GMSC MSC

27 Network Subscribers 27 PSTN PLM N GMSC MSC TRC BSC ISDN BSC/TRC HLR HLR Home Location Register

28 Home Location Register 28 Database which stores: Subscriptions MSISDN number IMSI number list of services VLR/MSC address Authentication and ciphering data AuC HLR GMSC MSC

29 Who is where? 29 PSTN PLM N GMSC VLR MSC TRC BSC ISDN BSC/TRC HLR VLR Visitor Location Register

30 Visitor Location Register 30 Database which stores: Subscriber location Subscriber services (copy from HLR) MS status Other flags and pointers DELETE HLR VLR MSC UPDATE VLR MSC

31 Security 31 PSTN PLM N GMSC VLR MSC TRC BSC ISDN BSC/TRC AUC HLR AuC Authentication Centre

32 Authentication Centre 32 Node which generates: Subscribers triplets RANDom number RAND Signed RESponse SRES Ciphering Key Kc AuC HLR

33 Triplet Provision 33 IMSI AuC Ki RAND A3 A8 SRES Kc RAND Triplet

34 Authentication Procedure 34 RAND VLR MSC IMSI attach RAND SRES = Access to network Ki RAND SRES A3

35 EIR Equipment Identity Register 35 PSTN PLM N GMSC VLR MSC TRC BSC ISDN BSC/TRC AUC EIR HLR EIR Equipment Identity Register

36 Equipment Identity Register 36 Database which stores: IMEI number Provides information about stolen equipment (black list) faulty equipment (grey list) unknown equipment EIR MSC

37 Short messages 37 PSTN PLM N GMSC VLR MSC TRC BSC ISDN BSC/TRC AUC SC EIR HLR SC Service Centre (SMS-C Short Message Service Centre)

38 Data transmission 38 PSTN PLM N GMSC VLR MSC D T I TRC BSC ISDN AUC BSC/TRC PCU GIWU SC EIR HLR PLMN SGSN Serving GPRS Support Node GGSN Gateway GPRS Support Node PCU Packet Control Unit INTERNE T GGSN SGSN DTI Data Transmission Interface GIWU GSM Interworking Unit

39 39 Radio Interface

40 How the radio works? 40 FDMA Frequency Division Multiple Access f1 f2 ONE FREQUENCY ONE STATION

41 TDMA Solution for GSM 41 TDMA Time Division Multiple Access f1 f1 ONE FREQUENCY MANY CALLS

42 Coverage Problem 42 Solution Frequency Reuse Interferences f1 f1 f2? f1

43 Frequency Reuse Factor

44 Interleaving and errors 44 I X 1 N X 1 F X 1 O 1 I 2 N 2 F 2 O 2 I 3 N 3 F 3 O 3 IX I 1 IX I 2 IX I 3 N 1 N 2 N 3 F 1 F 2 F 3 O 1 O 2 O 3 X X X N 1 N 2 N 3 F 1 F 2 F 3 O 1 O 2 O 3

45 Fading Problem 45 Shadowing Rayleigh

46 Frequency Hopping 46 Changing the carrier frequency at frequent intervals What is the time between hops? f1 f2 f3 f4 Fading dip

47 Path Loss Mobile Station is too far away from 47 Signal Strength Distance

48 Combined signal power 48

49 Handover 49 DURING THE CALL Another handles the call

50 Time Alignment 50 Information does not arrive within allocated time slot Time

51 Timing Advance 51 Information is sent earlier Possible range: µs (shift 3,69 µs) 3 3 TA Time

52 Air Link 52 Maximum Channel Capacity by C. E. Shannon (Kotelnykov)

53 A/D Conversion in GSM Sampling 8192 levels 2. Quantization 3. Coding 8kHz bits

54 Segmentation 54 20ms 20ms 20ms 20ms x samples * 13bits

55 Speech Coding 55 20ms 20ms 20ms 20ms bits

56 Channel Coding 56 VIB Very Important Bits IB Important Bits NSIB Not So Important Bits 50 VIB Block coder 53 1: IB Convolutional Coder 456 bits 4 Tail Bits 78 NSIB

57 Interleaving Stage , ms 02, , , , , , Burst BER = 25% 8, bits

58 Interleaving Stage bits 5, ms 6, , ms 8, , , , , Burst BER = 12,5%

59 Ciphering A5

60 Burst formatting 60 Training sequence Tail bits (000) Train. Seq. 1 1 tail tail

61 Training sequence equalization 61 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)

62 Modulation & Transmission 62 GMSK

63 Radio Interface Summary 63 Modulation & Transmission Burst formatting Ciphering/encryption Interleaving Channel coding Speech coding Segmentation A/D Conversion

64 64 Channels and Bursts

65 Up Link & Down Link 65 Up Link direction from MS to the network Down Link direction from the network to the MS

66 Channel Concept 1 P-GSM 900: Bandwidth 25MHz Duplex Distance 45MHz E-GSM 900: Extra 10 MHz bandwidth 66 EGSM Up Link EGSM Down Link MHz

67 Channel Concept 2 67 ARFCN Absolute Radio Frequency Channel Number Carrier separation 200kHz P-GSM900 Radio Channels FDMA 200 khz FDMA Frequency

68 Channel Concept 3 68 Time slot TS7 TS6 TS5 TS4 TS3 TS2 TS1 TS0 TS1 TS0 FDMA FDMA Frequency

69 Basic Physical Channel 69 BPC Basic Physical Channel TS7 TS6 TS5 TS4 TS3 TS2 TS0 TS1 TDMA Frame n n+1 n+2 n+3 n+4 n+5 Time

70 Logical Channels 70 Broadcast Common Control Dedicated Control Full Rate Half Rate CONTROL CHANNELS TRAFFIC CHANNELS LOGICAL CHANNELS

71 How to transfer information 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 kbps

72 How to transfer network info 72 Broadcast Channels (BCH) Frequency Correction Channel (FCCH) Synchronization Channel (SCH) Broadcast Control Channel (BCCH)

73 How to make or receive call 73 Common Control Channels (CCCH) Paging Channel (PCH) Random Access Channel (RACH) Access Grant Channel (AGCH)

74 How to make call set-up 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)

75 Channel Mapping 75 Traffic Channels TS7 TS6 TS5 TS4 TS3 TS2 TS0 TS1 C0 C1 C2 C3 Frequency Dedicated Control Channels Broadcast Channel Common Control Channel

76 76 Frames structure 1 hyperframe = 2048 superframes = TDMA frames (3h 28min 53s 760ms) superframe = 1326 TDMA frames (6,12 s) 51 (26-frame) multiframes or 26 (51-frame) multiframes TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 1 multiframe = 26 TDMA frames (120 ms) 1 multiframe = 51 TDMA frames (235 ms) Traffic Signalling 1 TDMA frame = 8 Timeslots (4,615 ms)

77 Frame number 51 TDMA frames Channel Mapping TS3 TS2 TS0 TS1 R R R R R TS5 TS4 R R C S F C C C C C C C C S F C C C C B B B B S F CUL0 CUL1 CDL0 CDL1 I Frequency Traffic Channels Dedicated Control Channels Broadcast Channel Common Control Channel 77

78 Channel Mapping TS0 78 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 Common Control Channel Dedicated Control Channels Broadcast Channel Traffic Channels

79 Channel Mapping 79 Frame number C C C C C S F C C C C C C C C S F C C B CC B B B S F D6 D6 D6 D6 D5 D5 D5 D5 D4 D4 D4 D4 D3 D3 D3 D3 D2 D2 D2 D2 D1 D1 D1 D1 D0 D0 D0 D0 TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 Traffic Channels Dedicated Control Channels Broadcast Channel Common Control Channel Time slot number

80 Full Rate vs Half Rate TCH 80 FR-TCH 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 TDMA frames = 120 ms Multiframe for xr traffic channels HR-TCH (two calls)

81 Channel Mapping 81 LOGICAL CHANNELS TCH-FR TCH-HR TCH BCCH SCH FCCH BCH PCH AGCH RACH CCCH SDCCH SACCH DCCH FACCH Normal Burst Synchr. Burst Access Burst Freq. Corr. Burst

82 Bursts 82 TS0 TS1 TS2 TS3 TS4 TS5 TS6 148 bits 30 s TS7 TB Tail Bits GP Guard Period Burst types: Normal NB 3 TB 57 Encrypted bits 1 flag 26 Train seq 1 flag 57 Encrypted bits 3 TB 8.25 GP Frequency Correction FB Synchronization SB Access AB 3 TB 142 Fixed bits 3 TB 8.25 GP 3 TB 39 Information bits 8 TB 41 Synchronization seq. 64 Synchronization seq. 36 Information bits 39 Information bits 3 TB 8.25 GP 3 TB GP

83 83 ID Numbers

84 Identity Numbers MSISDN 84 CC Country Code NDC National Destination Code SN Subscriber Number NDC SN CC NDC SN CC National Mobile Number MSISDN

85 International Mobile Subscriber Identity IMSI 85 MCC Mobile Country Code MNC Mobile Network Code MSIN Mobile Subscriber Identification Number MCC MNC MSIN MCC MNC MSIN IMSI

86 Temporary Mobile Station Identity TMSI 86 4 octets TMSI

87 International Mobile Equipment Identity IMEI 87 TAC Type Approval Code FAC Final Assembly Code SNR Serial Number *#06# TAC FAC SNR spare xxxxxxxx TAC FAC SNR IMEI

88 Mobile Station Roaming Number MSRN 88 CC Country Code NDC National Destination Code SN Servicing Number CC NDC SN CC NDC SN MSRN

89 Call to an MS (MSRN example) 89 PSTN MSISDN MSRN IMSI HLR PLMN VLR MSISDN MSRN GMSC MSRN MSC ISDN MSRN IMSI

90 Location Area Identity LAI 90 MCC Mobile Country Code MNC Mobile Network Code LAC Location Area Code MCC MNC LAC MCC MNC LAC LAI

91 Cell Global Identity CGI 91 LAI Location Area Identity CI Cell Identity LAI CI LAI CGI CI

92 92 Traffic Cases

93 IMSI Attach IMSI Attach is executed when the MS is switched on. IMSI Attach Ack. IMSI Attach ack. 93 SDCCH HLR VLR MSC IMSI Attach Authentication and other signalling IMSI Attach SDCCH Assign SDCCH Request Info about Synchronization Freq. correction SDCCH SDCCH AGCH RACH BCCH SCH FCCH BSC/TRC

94 Location Updating, same MSC/VLR 94 MS changes LA within same MSC/VLR Location Updating Ack. SDCCH Location Updating Request SDCCH HLR VLR MSC SDCCH Assign SDCCH Request (Reason Loc. Update) Different LAI LA2 AGCH RACH BCCH BSC/TRC LA1

95 Location Updating, new MSC/VLR 95 MS changes LA to new that belongs to a new MSC/VLR Location Updating Ack. SDCCH HLR DELETE VLR MSC Location Updating Request SDCCH UPDATE VLR MSC Different LAI AGCH BSC/TRC RACH BCCH

96 96 Call to MS MSISDN AuC EIR CALL TCH PSTN HLR Call set-up SDCCH Assign SDCCH AGCH PLMN ISDN GMSC Route VLR MSC Paging BSC/TRC SDCCH Request Paging Message RACH PCH

97 Call from MS 97 AuC EIR TCH PSTN HLR TCH Assign Call set-up SDCCH SDCCH PLMN VLR SDCCH Assign AGCH GMSC MSC SDCCH Request RACH ISDN BSC/TRC

98 Measurements measures: Signal strength Transmission quality on TCH up link 98 MS measures: Signal strength Transmission quality on TCH down link VLR MSC Decision about handover Measurement reports from MS are sent to BSC/TRC Measurement reports from MS and

99 Inter-BSC Handover 99 Handover between two cells controlled by different BSC Handover Required Handover Decision Release TCH Frequency Time Slot MS+ measurements Freq. TS MS measurements FACCH VLR MSC BSC/TRC Handover Request BSC/TRC HO Access B Activate TCH TA Handover Complete FACCH FACCH FACCH

100 Inter-MSC Handover 100 Handover between two cells controlled by different MSC/VLR UPDATE VLR MSC VLR MSC Handover Request Handover Required Decision BSC/TRC BSC/TRC Activate TCH Frequency MS+ Time Slot measurements HO Access B TA Freq. TS FACCH MS measurements FACCH FACCH Handover Complete FACCH Call Connection Completed

101 101 Any questions?

102 102 Thank you for your attention. Ericpol, DOTR Ericpol Telecom Sp. z o.o. Rafal.Watza@ericpol.pl Mobile:

103 103 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, ód, tel. (042) w ramach Europejskiego Funduszu Spo ecznego