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 83 w ramach Europejskiego www.kapitalludzki.p.lodz.pl Funduszu Spo ecznego
GSM Overview Rafa Watza, DOTR Ericpol Telecom Sp. z o.o. Rafal.Watza@ericpol.pl Tel.: +48 663 487959
Agenda 3 GSM History and services GSM Structure Radio Interface Channels and Bursts ID - Numbers Traffic Cases
4 GSM History
5 Early cellular systems NMT - Nordic Mobile Telephone AMPS - Advanced Mobile Phone Service TACS JTACS - Total Access Communication System - Japanese TACS NMT AMPS 1981 1983
6 1991 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 1850 1910 NMT GSM 900 GSM 1800 GSM 1900 UMTS 425 490 890 960 1710 1880 1920 2170 f [MHz]
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
Network evolution 8 Functionality IDEA Standardization Usage GSM Releases R7 R8 R9 R5 R6 R4 R96 R97 R98 R99 P1 P2 91/92 98 99/00 02 03 04/05 07 08 09 Time
GSM Phase 1 Services 9 Speech call Managing mobility SMS service Call barring Basic fax/data services Ciphering data
GSM Phase 2 Services 10 Calling line identification Conference calling Call holding / waiting GSM900 GSM1800 roaming EFR Speech codec SMS concatenation
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 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
Air Interface vs. Cable 14 MS consists of: How GSM Network is built? Equipment SIM Card GSM Networ k INTERNET PSTN ISDN +48 400 100200
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
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
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
Communication with Mobile Station 18 - Base Transceiver Station Cell area covered by Cell
Base Transceiver Station 19 Radio transmission Radio signal reception Signal processing Quality measurements Synchronization / maintenance Broadcasting system information BSC
Coverage optimisation 20 Rural environment low density Suburban environment average density City boundaries Urban environment high density Pico cell highest density
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
Base Station Controller 22 Radio network management administration and control Traffic measurements Connections handling Software handling TRC BSC
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
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
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
Gateway MSC 26 Interface to other networks Roaming interrogation Call forwarding PST N PLMN ISD N GMSC MSC
Network Subscribers 27 PSTN PLM N GMSC MSC TRC BSC ISDN BSC/TRC HLR HLR Home Location Register
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
Who is where? 29 PSTN PLM N GMSC VLR MSC TRC BSC ISDN BSC/TRC HLR VLR Visitor Location Register
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
Security 31 PSTN PLM N GMSC VLR MSC TRC BSC ISDN BSC/TRC AUC HLR AuC Authentication Centre
Authentication Centre 32 Node which generates: Subscribers triplets RANDom number RAND Signed RESponse SRES Ciphering Key Kc AuC HLR
Triplet Provision 33 IMSI AuC Ki RAND A3 A8 SRES Kc RAND Triplet
Authentication Procedure 34 RAND VLR MSC IMSI attach RAND SRES = Access to network Ki RAND SRES A3
EIR Equipment Identity Register 35 PSTN PLM N GMSC VLR MSC TRC BSC ISDN BSC/TRC AUC EIR HLR EIR Equipment Identity Register
Equipment Identity Register 36 Database which stores: IMEI number Provides information about stolen equipment (black list) faulty equipment (grey list) unknown equipment EIR MSC
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)
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 Radio Interface
How the radio works? 40 FDMA Frequency Division Multiple Access f1 f2 ONE FREQUENCY ONE STATION
TDMA Solution for GSM 41 TDMA Time Division Multiple Access f1 f1 ONE FREQUENCY MANY CALLS
Coverage Problem 42 Solution Frequency Reuse Interferences f1 f1 f2? f1
43 2 1 1 3 2 3 2 1 2 1 2 1 3 3 2 6 12 3 1 8 10 2 5 4 10 7 3 11 10 6 4 2 11 5 1 7 5 6 12 11 8 1 8 9 3 12 4 7 9 2 3 6 1 9 9 6 5 2 4 3 1 1 2 3 4 6 3 2 4 5 7 7 1 6 2 7 1 6 4 5 1 5 3 2 4 1 6 5 7 3 1 4 7 4 1 2 2 3 1 2 4 4 3 2 1 4 2 1 3 4 4 1 1 3 3 2 1 4 3 3 2 2 4 1 3 3 Frequency Reuse Factor
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
Fading Problem 45 Shadowing Rayleigh
Frequency Hopping 46 Changing the carrier frequency at frequent intervals What is the time between hops? f1 f2 f3 f4 Fading dip
Path Loss Mobile Station is too far away from 47 Signal Strength Distance
Combined signal power 48
Handover 49 DURING THE CALL Another handles the call
Time Alignment 50 Information does not arrive within allocated time slot 344 3 Time
Timing Advance 51 Information is sent earlier Possible range: 0 233 µs (shift 3,69 µs) 3 3 TA Time
Air Link 52 Maximum Channel Capacity by C. E. Shannon (Kotelnykov)
A/D Conversion in GSM 53 1. Sampling 8192 levels 2. Quantization 3. Coding 8kHz 0 1 1 1 0 0 0 0 0 0 1 1 1 13bits
Segmentation 54 20ms 20ms 20ms 20ms x samples * 13bits
Speech Coding 55 20ms 20ms 20ms 20ms 0100010001001001001000100000111110010100001010001011101 01010010110 260 bits
Channel Coding 56 VIB Very Important Bits IB Important Bits NSIB Not So Important Bits 50 VIB Block coder 53 1:2 378 132 IB Convolutional Coder 456 bits 4 Tail Bits 78 NSIB
Interleaving Stage 1 57 1, 9 ---------449 1 20ms 02, 10 - - - - - - - 450 13, 11 --------451 0 4, 12 - - - - - - - 452 1 5, 13 --------453 0 6, 14 --------454 1 7, 15 - - - - - - - 455 Burst BER = 25% 8, 16 - - - - - - - 456 57 bits
Interleaving Stage 2 58 57 bits 5, 13 -------453 1 20ms 6, 14 -------454 7, 15 - - - - - - - 455 20ms 8, 16 - - - - - - - 456 1, 9 --------449 02, 10 - - - - - - - 450 1 3, 11 -------451 4, 12 - - - - - - - 452 Burst BER = 12,5%
Ciphering 59 1 1 1 1 A5
Burst formatting 60 Training sequence Tail bits (000) 11 1 1Train. Seq. 1 1 tail tail
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)
Modulation & Transmission 62 GMSK
Radio Interface Summary 63 Modulation & Transmission Burst formatting Ciphering/encryption Interleaving Channel coding Speech coding Segmentation A/D Conversion
64 Channels and Bursts
Up Link & Down Link 65 Up Link direction from MS to the network Down Link direction from the network to the MS
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 890 915 935 960 MHz
Channel Concept 2 67 ARFCN Absolute Radio Frequency Channel Number Carrier separation 200kHz P-GSM900 Radio Channels 124 1 2 124 1 2 124 FDMA 200 khz FDMA Frequency
Channel Concept 3 68 Time slot TS7 TS6 TS5 TS4 TS3 TS2 TS1 TS0 TS1 TS0 FDMA FDMA Frequency
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
Logical Channels 70 Broadcast Common Control Dedicated Control Full Rate Half Rate CONTROL CHANNELS TRAFFIC CHANNELS LOGICAL CHANNELS
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
How to transfer network info 72 Broadcast Channels (BCH) Frequency Correction Channel (FCCH) Synchronization Channel (SCH) Broadcast Control Channel (BCCH)
How to make or receive call 73 Common Control Channels (CCCH) Paging Channel (PCH) Random Access Channel (RACH) Access Grant Channel (AGCH)
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)
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 Frames structure 1 hyperframe = 2048 superframes = 2 715 648 TDMA frames (3h 28min 53s 760ms) 0 1 2 2044 2045 2046 2047 1 superframe = 1326 TDMA frames (6,12 s) 51 (26-frame) multiframes or 26 (51-frame) multiframes 0 1 2 3 4 47 48 49 50 0 1 2 23 24 25 TS0 TS1 TS2 TS3 TS4 TS5 TS6 TS7 1 multiframe = 26 TDMA frames (120 ms) 1 multiframe = 51 TDMA frames (235 ms) 0 1 2 3 22 23 24 25 0 1 2 3 47 48 49 50 Traffic Signalling 1 TDMA frame = 8 Timeslots (4,615 ms)
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
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 0 1 6 22 32 50 Frame number Common Control Channel Dedicated Control Channels Broadcast Channel Traffic Channels
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
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 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 ms Multiframe for xr traffic channels HR-TCH (two calls)
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
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 68.25 GP
83 ID Numbers
Identity Numbers MSISDN 84 CC Country Code NDC National Destination Code SN Subscriber Number NDC SN 48 601 123456 CC NDC SN CC National Mobile Number MSISDN
International Mobile Subscriber Identity IMSI 85 MCC Mobile Country Code MNC Mobile Network Code MSIN Mobile Subscriber Identification Number 260 03 39508409 MCC MNC MSIN MCC MNC MSIN IMSI
Temporary Mobile Station Identity TMSI 86 4 octets TMSI
International Mobile Equipment Identity IMEI 87 TAC Type Approval Code FAC Final Assembly Code SNR Serial Number *#06# TAC FAC SNR spare 35 0010 xxxxxxxx TAC FAC SNR IMEI
Mobile Station Roaming Number MSRN 88 CC Country Code NDC National Destination Code SN Servicing Number 48 663 426592 CC NDC SN CC NDC SN MSRN
Call to an MS (MSRN example) 89 PSTN MSISDN MSRN IMSI HLR PLMN VLR MSISDN MSRN GMSC MSRN MSC ISDN MSRN IMSI
Location Area Identity LAI 90 MCC Mobile Country Code MNC Mobile Network Code LAC Location Area Code 260 03 65536 MCC MNC LAC MCC MNC LAC LAI
Cell Global Identity CGI 91 LAI Location Area Identity CI Cell Identity 2600365536 12345 LAI CI LAI CGI CI
92 Traffic Cases
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
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
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 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
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
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
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
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 Any questions?
102 Thank you for your attention. Ericpol, DOTR Ericpol Telecom Sp. z o.o. Rafal.Watza@ericpol.pl Mobile: +48 663 487 959
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 83 w ramach Europejskiego www.kapitalludzki.p.lodz.pl Funduszu Spo ecznego