GSM TOWARDS LTE NETWORKS Lecture # 2

CELLULAR GENERATIONS First Generation Wireless : Analog Second Generation Wireless (2G): Digital Second Generation Wireless + (2G+): More Data Third Generation Wireless (3G):  Universal Global Wireless Voice and Data System Worldwide Effort Toward 3G  International Standard Underway: IMT-2000

3 1 st GENERATION CELLULAR SYSTEM Widespread introduction in early 1980s. Analogue modulation. Frequency division multiple access. Voice traffic only. No inter-network roaming possible. Insecure air interface. Examples :  AMPS (Advance mobile Phone System, American based,800MHz)  TACS (Total Access Communications System, UK based,900MHz)  C-450 (German standard, 450MHz)  JTACS (Japanese Total Access Communications System,900MHz).

4 2 nd GENERATION OF CELLULAR NETWORKS Widespread introduction in 1990s. Use digital modulation. Variety of multiple access strategies. More efficient use of radio spectrum. International roaming capability. Secure air interface. Compatibility with ISDN.

5 GSM ARCHITECTURE OVERVIEW A GSM system is made up of three subsystems:  The mobile station (MS)  The Base station subsystem (BSS)  The Network and switching subsystem (NSS) The interfaces defined between each of these sub systems include:  “A” interface between NSS and BSS  “Abis” interface between BSC and BTS (Within the BSS)  “Um” air interface between the BSS and the MS

GSM ARCHITECTURE OVERVIEW Main components of GSM  The mobile station (MS)  BSS Base Station Subsystem (BTS+BSC)  MSS Mobile Station Subsystem (MSC/HLR,..) BSC BTS MSC

7 Abis Interface Interface

GSM NETWORK / DEPARTMENT OVERVIEW / 2G NETWORK RAN department RF department NSS department Transmission department

NMC and OMC BSS Signaling transmission Call connections and signaling transmission AUC VL R HL R EIR SS Switching Systems Base Station Systems MS Other Networks GSMOverview 00/9 GMSC MSC BTS BSC GSM system

10 GSM Call Setup

11 MSMobile Station = phone + SIM card BTSBase Transceiver Station BSCBase Station Controller HLRHome Location Register MSCMobile services Switching Centre VLRVisitor Location Register AUCAuthentication Centre Stand-alone or integrated in HLR EIREquipment Identity Register For blacklisting stolen and unwanted equipment SMSCShort Message Service ”Support” Centre VMSVoice Messaging System PrePaid Node Hosting prepaid service system IN Intelligent Network services PSTNPublic Switched Telephone Network PABXPrivate Automatic Branch Exchange MSC/VLR Warid Telenore BSC SMSC EIR INTERNET Mobilink PSTN BSC PrePaid Node VMS HLR MSC w AUC

12 MSC SMSC EIR INTERNET PABX PSTN International PSTN Fixed Network BSC IN PrePaid VMS Voic HLR MSCBSC

13 MSC SMSC EIR INTERNET BSC IN PrePaid VMS Voic HLR MSCBSC PABX PSTN International PSTN Fixed Network

14 MSC SMSC EIR INTERNET BSC IN PrePaid VMS Voic HLR MSCBSC PABX PSTN International PSTN Fixed Network

15 MSC SMSC EIR INTERNET BSC IN PrePaid VMS Voic HLR MSCBSC PABX PSTN International PSTN Fixed Network

16 BSC Base Station Controller The call request reaches the BSC from the BTS and is forwarded to MSC. The call request reaches the BSC from the BTS and is forwarded to MSC. After call is established, the BSC will perform decoding of the call (in typical config.) After call is established, the BSC will perform decoding of the call (in typical config.)

17 BSC HLR MSC SMSC EIR INTERNET IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network

18 BSC HLR MSC SMSC EIR INTERNET IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network

19 BSC HLR MSC SMSC EIR INTERNET IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network

20 Checks A number. Checks A number. To whom is A subscriber calling? (Checks B number) To whom is A subscriber calling? (Checks B number) Example : A subscriberhas prepaid number. Example : A subscriber has prepaid number. MSC Mobile Switching Centre

21 BSC HLR MSC SMSC EIR INTERNET IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network

22 BSC HLR MSC SMSC EIR INTERNET IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network

23 BSC HLR MSC SMSC EIR INTERNET IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network

24 Does the A subscriber have money left on his/her account? Does the A subscriber have money left on his/her account? When the call is established and on-going the subscriber’s account is decremented accordingly. When the call is established and on-going the subscriber’s account is decremented accordingly. PrePaid Node

25 BSC HLR MSC SMSC EIR INTERNET IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network

26 BSC HLR MSC SMSC EIR INTERNET IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network

27 BSC HLR MSC SMSC EIR INTERNET IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network

28 Where is the B subscriber? Where is the B subscriber? MSC interrogates in HLR. (HLR = Home Location Register) MSC interrogates in HLR. (HLR = Home Location Register) MSC Mobile Switching Centre Mobile Switching Centre

29 BSC HLR MSC IN PrePaid VMS Voic MSCBSC PABX PSTN International PSTN Fixed Network SMSC EIR INTERNET

30 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

31 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

32 HLR says ’I am the home of the B subscriber and I know where he/she is right now’ (i.e. which VLR) HLR says ’I am the home of the B subscriber and I know where he/she is right now’ (i.e. which VLR) Tells this VLR ’Give me a visitor address for this subscriber’ (Roaming Number) Tells this VLR ’Give me a visitor address for this subscriber’ (Roaming Number) HLR Home Location Register

33 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

34 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

35 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

36 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

37 BSC HLR MSC MSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

38 Hosting MSC/VLR returns TEMPORARILY assigned visitor/roaming address for B- subscriber to HLR. Hosting MSC/VLR returns TEMPORARILY assigned visitor/roaming address for B- subscriber to HLR. MSC Mobile Switching Centre

39 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

40 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

41 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

42 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

43 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

44 ’Thanks for the visitor address!’ ’Thanks for the visitor address!’ ’I will send this address to the MSC that requested for it.’ ’I will send this address to the MSC that requested for it.’ HLR Home Location Register

45 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

46 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

47 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

48 ’Thank you, HLR!’ ’Thank you, HLR!’ Speech connection path will set up now towards the MSC/VLR where the B subscriber is presently located. Speech connection path will set up now towards the MSC/VLR where the B subscriber is presently located. MSC Mobile Switching Centre

49 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

50 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

51 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

52 Sets up a speech connection towards BSC. Sets up a speech connection towards BSC. Delivers B-subscriber ID to BSC and asks to page for the subscriber using that ID. Delivers B-subscriber ID to BSC and asks to page for the subscriber using that ID. MSC Mobile Switching Centre

53 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

54 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

55 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

56 BSC now sends a PAGING MESSAGE to all the BTSs that it covers/controls. BSC now sends a PAGING MESSAGE to all the BTSs that it covers/controls. Carrys PAGING RESPONSE from called MS back to MSC. Carrys PAGING RESPONSE from called MS back to MSC. Allocates a RADIO channel through a BTS with best available and allowable SIGNAL STRENGTH for called MS. Allocates a RADIO channel through a BTS with best available and allowable SIGNAL STRENGTH for called MS. Performs SPEECH CODING when call is established. Performs SPEECH CODING when call is established. BSC Base Station Controller

57 BSC HLR MSC MSCBSC PABX PSTN International PSTN Fixed Network IN PrePaid VMS Voic SMSC EIR INTERNET

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