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J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 1 Telecommunications Concepts Chapter 2.1 The Circuit Switched Telephone Network.

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Presentation on theme: "J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 1 Telecommunications Concepts Chapter 2.1 The Circuit Switched Telephone Network."— Presentation transcript:

1 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 1 Telecommunications Concepts Chapter 2.1 The Circuit Switched Telephone Network

2 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 2 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

3 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 3 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

4 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 4 The Telephone Network Analog / Digital PABX SW PABX SW

5 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 5 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

6 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 6 The Fixed Access Network Analog phone on analog switch Line circuit Analog switch twisted pair, average length 2.5 Km Signaling (DTMF or pulse) and voice multiplexed In Belgium : last one went out of service in 2002

7 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 7 The Fixed Access Network Analog phone on digital switch Line circuit Digital switch Digital Analog twisted pair, average length 2.5 Km Signaling (DTMF or pulse) and voice multiplexed In Belgium : the most common situation

8 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 8 The Fixed Access Network The ISDN Basic Access twisted pair, average length 2.5 Km 144Kb/s modem Digital switch 144Kb/s modem S bus 2 * 64 Kb/s + 16 Kb/s TDM In Belgium : e.g. the Belgacom TWIN

9 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 9 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

10 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 10 The Mobile Access Network Mobility Management NSS HLR VLR PSTN MSC NSS BSS 16 Kb/s 13 Kb/s 64 Kb/s BSS : Base Station Subsystem NSS : Network & Switching Subsystem HLR : Home Location Register VLR : Visitors Location Register MSC : Mobile Switching Center

11 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 11 The Mobile Access Network Mobility Management Mobile terminal identification –SIM card with unique id. –Data about SIM stored in HLR of operator who owns SIM –Phone calls directed to HLR of operator Mobile terminal localization –BSS regularly makes broadcasts in its cells –Mobile selects best cell and sends its SIM id. –Presence of mobile recorded in local VLR –SIMs owner HLR updated with applicable VLR Handover –When location of mobile changes during conversation –Circuit routing modified on the fly –Sound quality briefly degraded –Handover not available between different operators

12 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 12 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

13 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 13 The Mobile Access Network GSM radio system time frequency 15/26 ms 200 KHz 45 MHz Tx Rx 3 radio slots A combination of FDM and TDM Two separate frequency bands used for Tx and Rx Slow frequency hopping for propagation diversity Sender and receiver sequences shifted by 45MHz and 3 slots Predefined time slot for signaling channel

14 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 14 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

15 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 15 The Mobile Access Network Wireless interference margins cause considerable loss in transmission capacity Considerable room for improvements by controlling interferences : Fast frequency hopping spread spectrum radio with Code Domain Multiple Access =Third generation mobile networks (UMTS) Frequency Space Time

16 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 16 The Mobile Access Network Data combined with known higher frequency pseudo random sequence Resulting modulated radio signal has high bandwidth Shannon : low data rate combined with high bandwidth = excellent noise margins! Fast hopping Spread Spectrum n b/s Data Pseudo- random sequence m * n b/s xor HF carrier Modulated signal Large bandwidth m times bandwidth needed for data

17 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 17 The Mobile Access Network Spread Spectrum and CDMA D1D1 S1S1 xor HF Tx1 D2D2 S2S2 xor HF Tx2 D2D2 S2S2 HF Correl -ator Rx2 D1D1 S1S1 HF Correl -ator Rx1 For radio link Tx1-Rx1, emission by Tx2 is just another source of noise

18 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 18 The Mobile Access Network Multi-path Interference GSM : interference = noise UMTS : correlator adds similar input signals with appropriate delays so that they reinforce each other Different paths have different lengths and different delays

19 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 19 The Mobile Access Network Third Generation Handover When a receiver is between two cells, both transmitters send the same signal. These two signals reinforce each other, as multipath propagation does.

20 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 20 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

21 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 21 Time Domain Multiplexing Synchronous multiplexing Unique bit pattern to delimit frames XX

22 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 22 Primary Multiplexing Trunk Network (E1 = CEPT30) Digital switch Digital switch n*30*64 Kb/s n*2048 Kb/s

23 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 23 Primary Multiplexing Trunk Network (T1 = Bell D2) Digital switch Digital switch n*23*64 Kb/s n*1544 Kb/s

24 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 24 The ISDN Primary Rate for connecting Private Branch Exchanges Digital switch 2048 Kb/s (CEPT30) E1 Optical Fiber or Microwave Link PABX pabx e.g: VUB : 4 E1 lines = 120 simultaneous calls

25 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 25 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

26 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 26 Higher Order Multiplexing Optical Fiber or Microwave Link Digital switch Digital switch

27 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 27 Synchronous Multiplexing of almost synchronous data flows DCBAE SRQPT F ESTDCBARQP01F 1 Frame SC f out > n * MAX(f in ) Primary rate dataflows to be multiplexed can be derived from independent clocks !

28 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 28 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

29 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 29 Plesiochronous Digital Hierarchy –Each multiplexed section has its own clock –Each level of multiplexing has its own clock –Frame structure from multiplexed signals is not explicitly present in the multiplexed stream >Full demultiplexing required at each node !

30 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 30 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

31 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 31 Synchronous Digital Hierarchy STM-1 Up to 63 channels at 2 Mb/s –The entire trunk network has one clock –Multiplexed stream based on 125 S frames –Different channels can each have their own asynchronous clock. –Add-drop multiplexers

32 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 32 Synchronous Digital Hierarchy SDH - SONET Data rateCCITTUSA-Elec.USA-Opt STS-1OC STM-1STS-3OC STM-3STS-9OC STM-4STS-12OC STM-6STS-18OC STM-8STS-24OC STM-12STS-36OC STM-16STS-48OC-48...

33 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 33 SDH Rings 34 Mb/s 2 Mb/s

34 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 34 SDH Rings

35 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 35 SDH Rings

36 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 36 SDH Rings The MCI Belgian Network

37 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 37 SDH Rings CUT !

38 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 38 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

39 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 39 Telephone Exchange (Conceptual Model) Switching Matrix Line Circuit Control Computer trunk lines + Inter-office signaling Register

40 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 40 Signaling system generations SS1 - SS5 : Analog call forwarding between exchanges SS6 : First digital signaling system –monolithic communications system (no layers) –Full mesh of virtual circuits, based on 2400 b/s links SS7 : Signaling system for the intelligent network –uses any digital link, satellites included –layered, OSI inspired, network architecture –supports "intelligent network" applications »Non-geographic numbers (800) »CLIP, Call forwarding, Conference calls, etc... »Number portability, Carrier selection »Mobility & roaming IP ???

41 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 41 The Telephone Network X X Non-geographic Numbering database 0800

42 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 42 The Telephone Network Number portability Ported numbers

43 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 43 Contents Traditional Overall structure – Access network »Fixed lines »Wireless access GSM UMTS –Trunk network »Primary multiplexing : E1 / T1 lines »Higher order multiplexing Plesiochronous Data Hierarchy Synchronous Data Hierarchy –Exchanges and signaling General purpose SDH networks

44 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 44 General Purpose SDH Networks PABX

45 J.Tiberghien - VUB10-05-K.Steenhaut & J.Tiberghien - VUB 45 Bibliography To know More about Telephony Recommended for this chapter John C. BELLAMY Digital Telephony Third edition John Wiley, ISBN :


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