1. INTRODUCTION TO GSM

7. FEATURES OF GSM

14. NETWORK COMPONENTS

15. NETWORK COMPONENTS UM UM ABIS A B C D F H

17. M obile S witching C entre (MSC) – Lucent MSC NETWORK COMPONENTS

25. Equipment Identity Register ( EIR ) White List All Valid assigned ID’s Range 1 Range 2 Range n Black List Service denied MS IMEI 1 MS IMEI 2 MS IMEI n Grey List Service allowed but noted MS IMEI 1 MS IMEI 2 MS IMEI n EIR NETWORK COMPONENTS

30. AUTHENTICATION PROCESS HLR AUC TRIPLES RAND, Kc , SRES VLR RAND Kc SRES RAND SRES SRES SRES = SRES BTS A5 , HYPERFRAME NUM Kc AIR INTERFACE ENCRYPTION MS A3 , A8 , A5 , Ki SRES = A3 (RAND , Ki ) Kc = A8 (RAND , Ki ) Ki, A3, A8 A3 ( RAND, Ki ) = SRES A8 ( RAND, Ki ) = Kc Triples Generated NETWORK COMPONENTS

33. TRANSCODER(XCDR) - Siemens NETWORK COMPONENTS

34. TRANSCODING 30 Timeslots 1 traffic channel / TS 64 Kbps / TS 4 E1 lines = 30 X 4 =120 Timeslots Each Timeslot =16 X 4 = 64 Kb/s 30 timeslots = 30 x 4 =120 traffic channels MSC XCDR BSC 0 1 2 31 16 Transcoded information from four calls NETWORK COMPONENTS

36. B ase Station Controller (B SC ) – Siemens BSC NETWORK COMPONENTS

38. Base Transceiver Station (BTS ) NETWORK COMPONENTS

39. MSC BSC BTS12 BTS1 BTS2 BTS4 BTS3 BTS11 BTS13 BTS14 BTS5 BTS6 BTS7 BTS8 BTS9 BTS11 Open ended Daisy Chain Daisy Chain with a fork. Fork has a return loop back to the chain Star Daisy Chain with a fork. Fork has a return loop back to the chain BTS Connectivity NETWORK COMPONENTS

41. Operation And Maintenance Centre For Radio ( OMC-R ) NETWORK COMPONENTS

44. MOBILE MAXIMUM RANGE RANGE= TIMING ADVANCE = DELAY OF BITS (0-63) BIT PERIOD= 577/156.25 = 3.693  sec =3.693 * 10e-6 sec VELOCITY= 3 * 10e5 Km/sec RANGE= 34.9 Km TIMIMG ADVANCE * BIT PERIOD* VELOCITY 2

47. INTERFACE NAMES Each interface specified in GSM has a name associated with it . NAME INTERFACE Um MS ----- BTS Abis BTS ----- BSC A MSC ------ BSC B MSC ------ VLR C MSC ------ HLR D VLR ----- HLR E MSC ------ MSC F MSC ------ EIR G VLR ------ VLR H HLR ------ AUC

48. 2 Mbits/s Trunk 30- channel PCM This interface carries the traffic from the PSTN to the MSC, between MSC’s, from the MSC to the BSC’s and from the BSC’s to the BTS’s. It represents the physical layer in the OSI model. Each 2 Mb/s link provides 30 traffic channels available to carry speech ,data or control information. Typical Configuration TS 0 TS 1-15 TS 16 TS 17 - 31 TS 0 - Frame allignment/ Error checking/ Signalling/ Alarms TS 1-15 , 17-31 - Traffic TS 16 - Siganlling

49. BSS CONNECTIONS MSC XCDR BSC BTS BTS BTS OMC CBC MTL (C7 ) OML (X.25) RSL ( LAPD) CBL

50. Cell Global Identity ( CGI ) : MCC MNC LAC CI MCC MNC LAC CI LAI CGI = Mobile Country Code = Mobile Network Code = Location Area Identity = Cell Identity

52. GSM Traffic Channels Traffic Channels TCH/F Full rate 22.8kbits/s TCH/H Half rate 11.4 kbits/s CHANNEL CONCEPT

53. GSM Control Channels BCH ( Broadcast channels ) Downlink only Control Channels DCCH( Dedicated Channels ) Downlink & Uplink CCCH( Common Control Chan ) Downlink & Uplink Synch. Channels RACH Random Access Channel CBCH Cell Broadcast Channel SDCCH Standalone dedicated control channel ACCH Associated Control Channels SACCH Slow associated Control Channel FACCH Fast Associated Control Channel PCH/ AGCH Paging/Access grant FCCH Frequency Correction channel SCH Synchronisation channel BCCH Broadcast control channel CHANNEL CONCEPT

57. NORMAL BURST 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 57 bits 57 bits 26 bits 3 3 FRAME1(4.615ms) FRAME2 Training sequence Data Data Tail Bits Tail Bits Flag Bit Flag Bit Guard Period Guard Period 0.546ms 0.577ms Carries traffic channel and control channels BCCH, PCH, AGCH, SDCCH, SACCH and FACCH. CHANNEL CONCEPT

58. Data - Two blocks of 57 bits each. Carries speech, data or control info. Tail bits - Used to indicate the start and end of each burst. Three bits always 000. Guard period - 8.25 bits long. The receiver can only receive and decode if the burst is received within the timeslot designated for it.Since the MS are moving. Exact synchronization of burst is not possible practically. Hence 8.25bits corresponding to about 30us is available as guard period for a small margin of error. Flag bits - This bit is used to indicate if the 57 bits data block is used as FACCH. Training Sequence - This is a set sequence of bits known by both the transmitter and the receiver( BCC of BSIC). When a burst of information is received the equaliser searches for the training sequence code. The receiver measures and then mimics the distortion which the signal has been subjected to. The rece i ver then compares the received data with the distorted possible transmitted sequence and chooses the most likely one. NORMAL BURST CHANNEL CONCEPT

66. 0 10 20 30 40 50 50 40 30 20 10 0 IDLE CCCH BLOCK BCCH BLOCK SCH BLOCK FCCH BLOCK BCCH/CCCH NON-COMBINED MULTIFRAME RACH BLOCK Downlink Uplink

67. 0 10 20 30 40 50 50 40 30 20 10 0 IDLE CCCH BLOCK BCCH BLOCK SCH BLOCK FCCH BLOCK BCCH/CCCH COMBINED MULTIFRAME 51 101 101 51 RACH BLOCK SDCCH/4 SACCH/4 Downlink Uplink

68. 0 10 20 30 40 50 50 40 30 20 10 0 IDLE DCCH/8 MULTIFRAME 51 101 101 51 SDCCH/8 SACCH/C8 Downlink Uplink

69. 0 1 0 1 2 2045 2046 2047 1 Hyperframe = 2048 superframes = 2,715,648 TDMA frames 3h 28min 53s 760ms 1 Superframe = 1326 TDMAframes = 51(26 fr) 0r 26(51 fr) multiframes 1 2 3 49 48 47 50 0 1 24 25 0 1 2 23 24 25 0 48 1 2 49 50 2 3 4 5 6 7 6.12s 0 235.38ms 120ms Control 51 - Frame Multiframe Traffic 26 - Frame Multiframe 4.615ms TDMA Frame HYPERFRAME AND SUPERFRAME STRUCTURE CHANNEL CONCEPT

70. SPEECH CODING CHANNEL CODING INTERLEAVING BURST ASSEMBLING CIPHERING MODULATION DEMODULATION DECIPHERING BURST DISASSEMBLING DEINTERLEAVING CHANNEL DECODING SPEECH DECODING Transmission CODING, INTERLEAVING CIPHERING

76. Speech Channel Coding Class 1a 50 bits Class 1b 132 bits Class 1a 50 bits Class 1b 132 bits 378 bits Class 2 78 bits 3 4 Parity check Tail bits 260 bits 456 bits Convolution coding CODING

81. 4 GSM SPEECH CHANNEL INTERLEAVING ( Diagram ) 1 2 3 5 6 4 456 bits 5 456 bits 6 456 bits Full rate encoded speech blocks from a single conversation Bursts TDMA Frames Frame 1 Frame 2 Frame 3 Frame 4 INTERLEAVING

85. SIGNALLING Other Networks

89. SIGNALING IN TELECOMMUNICATION NETWORK DIGITAL SUBSCRIBER SIG. SUBSCRIBER LINE SIG. ACCESS SIG SIGNALLING TRUNK SIGNALLING CHANNEL ASSOCIATED SIG. COMMON CHANNEL SIG.

96. PHYSICAL LINK NETWORK TRANSPORT SESSION PRESENTATION OSI MODEL REFERENCE DIAGRAM APPLICATION PHYSICAL LINK NETWORK TRANSPORT SESSION PRESENTATION APPLICATION

106. CCITT SS NO. 7 PROTOCOLS IN GSM

110. PHYSICAL LINK NETWORK TRANSPORT SESSION PRESENTATION APPLICATION SIGNALLING DATA LINK SIGNALLING LINK SIGNALLING NETWORK SCCP TCAP USER PARTS ASE OSI Model CCITT SS NO 7 Model MTP NSP

111. CALL FLOW

112. Mobile originated call MS Channel Request (RACH) BSS MSC SDCCH Seizure Immediate Assignment [ Reject ] (AGCH) CM Service Request + Connection Request < CMSREQ > Connection [ Confirmed / Refused ] Link Establishment Authentication Request Authentication Response DT1 <CICMD> Ciphering Mode Command Ciphering Mode Complete DT1 <CICMP> Identity Request Identity Response Setup Call Proceeding Connection Management Assignment Request Assignment Request [ Failed ] Assignment Command Assignment [ Complete / Failure ] Assignment [ Complete / Failure ] TCH Seizure S D C C H T C H

113. MS BSS MSC Paging SDCCH Seizure Link Establishment Paging Request (PCH) UDT < PAGIN > Paging Channel Request (RACH) Immediate Assignment [ Reject ] (AGCH) Paging Response + Connection Request < PAGRES > Connection [ Confirmed / Refused ] Authentication Request Authentication Response S D C C H Ciphering Mode Command Ciphering Mode Complete DT1 <CICMD> DT1 <CICMP> Identity Request Identity Response Setup Call Confirmed Connection Management Assignment Request Assignment Request [ Failed ] Assignment Command Assignment [ Complete / Failure ] T C H TCH Seizure Assignment [ Complete / Failure ] Mobile terminated call

114. POWER CONTROL

134. PAGING Example cch_conf = 0 bs_ag_blk_res = 1 bs_pa_mfrms = 2 If cch_conf = 1 minimum = 2 If cch_conf = 6 Maximum = 81 * 4 M in time between pages = 2 * 235.5 = 471ms Max time between pages = 9 * 235.5 =2.1195 sec

137. AVAILABLE PAGING BLOCKS ON 1 CCCH_GROUP Maximum AGCH reservation for non-combined multiframe = 7 Available paging blocks = 2 Maximum AGCH reservation for combined multiframe = 1 Available paging blocks = 2 Minimum AGCH reservation for non-combined multiframe = 0 Available paging blocks = 9 Minimum AGCH reservation for combined multiframe = 0 Available paging blocks = 3 No of paging blocks will have a range of 2 - 9

138. CALCULATION OF CCCH AND PAGING GROUP NO CCCH_GROUP = [ ( IMSI mod 1000) mod (BS_CC_CHANS * N ) ] div N Paging group no = [ ( IMSI mod 1000) mod (BS_CC_CHANS * N ) ] mod N

139. HANDOVER

150. The following measurements is be continuously processed in the BSS : i) Measurements reported by MS on SACCH - Down link RXLEV - Down link RXQUAL - Down link neighbor cell RXLEV ii) Measurements performed in BSS - Uplink RXLEV - Uplink RXQUAL - MS-BS distance - Interference level in unallocated time slots Every SACCH multiframe (480 ms) a new processed value for each of the measurements is calculated.. HANDOVER HANDOVER

156. LOCATION UPDATE

159. LOCATION UPDATE

163. SYSTEM INFORMATION MESSAGES

170. SYSTEM INFORMATION 3 Location Area Identity Cell Identity SYS INFORMATION MESSAGES