Telecommunications Concepts Chapter 2 1 The Circuit Switched

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Telecommunications Concepts Chapter 2. 1 The Circuit Switched Telephone Network 1 10 -05 -K.

Telecommunications Concepts Chapter 2. 1 The Circuit Switched Telephone Network 1 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 2 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 3 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Telephone Network Analog / Digital SW SW SW PABX SW 4 10 -05

The Telephone Network Analog / Digital SW SW SW PABX SW 4 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 5 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Fixed Access Network Analog phone on analog switch Analog switch twisted pair, average

The Fixed Access Network Analog phone on analog switch Analog switch twisted pair, average length 2. 5 Km Signaling (DTMF or pulse) and voice multiplexed Line circuit In Belgium : last one went out of service in 2002 6 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Fixed Access Network Analog phone on digital switch Digital Analog twisted pair, average

The Fixed Access Network Analog phone on digital switch Digital Analog twisted pair, average length 2. 5 Km Signaling (DTMF or pulse) and voice multiplexed Line circuit In Belgium : the most common situation 7 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Fixed Access Network The ISDN Basic Access Digital switch S bus 144 Kb/s

The Fixed Access Network The ISDN Basic Access Digital switch S bus 144 Kb/s modem twisted pair, average length 2. 5 Km 2 * 64 Kb/s + 16 Kb/s TDM 144 Kb/s modem In Belgium : e. g. the Belgacom TWIN 8 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 9 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Mobile Access Network Mobility Management HLR : Home Location Register VLR : Visitors

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

The Mobile Access Network Mobility Management • Mobile terminal identification – SIM card with

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 SIM’s owner HLR updated with applicable VLR • Handover – – 11 When location of mobile changes during conversation Circuit routing modified “on the fly” Sound quality briefly degraded Handover not available between different operators 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 12 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Mobile Access Network GSM radio system • A combination of FDM and TDM

The Mobile Access Network GSM radio system • 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 45 MHz and 3 slots • Predefined time slot for signaling channel frequency 45 MHz Tx 200 KHz Rx 3 radio slots 13 15/26 ms time 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 14 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Mobile Access Network Wireless interference margins cause considerable loss in transmission capacity Frequency

The Mobile Access Network Wireless interference margins cause considerable loss in transmission capacity Frequency • Considerable room for improvements by controlling interferences : Fast frequency hopping spread spectrum radio with Code Domain Multiple Access = Third generation mobile networks (UMTS) Time Space 15 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Mobile Access Network Fast hopping Spread Spectrum Data n b/s Modulated signal Large

The Mobile Access Network Fast hopping Spread Spectrum Data n b/s Modulated signal Large bandwidth ≈ m times bandwidth needed for data xor Pseudo- m * n b/s random sequence HF carrier • 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! 16 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Mobile Access Network Spread Spectrum and CDMA D 1 Tx 1 S 2

The Mobile Access Network Spread Spectrum and CDMA D 1 Tx 1 S 2 xor S 1 HF D 2 Tx 2 HF S 1 xor S 2 HF HF Correl -ator D 2 Rx 2 Correl -ator D 1 Rx 1 For radio link Tx 1 -Rx 1, emission by Tx 2 is just another source of noise 17 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Mobile Access Network Multi-path Interference Different paths have different lengths and different delays

The Mobile Access Network Multi-path Interference Different paths have different lengths and different delays GSM : interference = noise UMTS : correlator adds similar input signals with appropriate delays so that they reinforce each other 18 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Mobile Access Network Third Generation Handover When a receiver is between two cells,

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. 19 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 20 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Time Domain Multiplexing Synchronous multiplexing 1 0 0 1 1 0 0 0 1

Time Domain Multiplexing Synchronous multiplexing 1 0 0 1 1 0 0 0 1 1 XX 0 1 Unique bit pattern to delimit frames 21 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Primary Multiplexing Trunk Network (E 1 = CEPT 30) Digital switch n*30*64 Kb/s n*2048

Primary Multiplexing Trunk Network (E 1 = CEPT 30) Digital switch n*30*64 Kb/s n*2048 Kb/s 22 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Primary Multiplexing Trunk Network (T 1 = Bell D 2) Digital switch n*23*64 Kb/s

Primary Multiplexing Trunk Network (T 1 = Bell D 2) Digital switch n*23*64 Kb/s n*1544 Kb/s 23 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The ISDN Primary Rate for connecting Private Branch Exchanges Digital switch pabx PABX E

The ISDN Primary Rate for connecting Private Branch Exchanges Digital switch pabx PABX E 1 Optical Fiber or Microwave Link 2048 Kb/s (CEPT 30) e. g: VUB : 4 E 1 lines = 120 simultaneous calls 24 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 25 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Higher Order Multiplexing Digital switch Optical Fiber or Microwave Link 26 10 -05 -K.

Higher Order Multiplexing Digital switch Optical Fiber or Microwave Link 26 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Synchronous Multiplexing of almost synchronous data flows Primary rate dataflows to be multiplexed can

Synchronous Multiplexing of almost synchronous data flows Primary rate dataflows to be multiplexed can be derived from independent clocks ! F E D C B 1 Frame A T F S E T S R Q P D 1 0 R C Q B P A S C fout > n * MAX(fin) 27 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 28 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Plesiochronous Digital Hierarchy – Each multiplexed section has its own clock – Each level

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 ! 29 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 30 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Synchronous Digital Hierarchy – The entire trunk network has one clock – Multiplexed stream

Synchronous Digital Hierarchy – 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 STM-1 Up to 63 channels at 2 Mb/s 31 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Synchronous Digital Hierarchy SDH - SONET Data rate 51. 84 155. 52 466. 56

Synchronous Digital Hierarchy SDH - SONET Data rate 51. 84 155. 52 466. 56 622. 08 933. 12 1244. 16 1866. 24 2488. 32. . . 32 CCITT STM-1 STM-3 STM-4 STM-6 STM-8 STM-12 STM-16. . . USA-Elec. STS-1 STS-3 STS-9 STS-12 STS-18 STS-24 STS-36 STS-48. . . USA-Opt. OC-1 OC-3 OC-9 OC-12 OC-18 OC-24 OC-36 OC-48. . . 10 -05 -K. Steenhaut & J. Tiberghien - VUB

SDH Rings 34 Mb/s 33 2 Mb/s 10 -05 -K. Steenhaut & J. Tiberghien

SDH Rings 34 Mb/s 33 2 Mb/s 10 -05 -K. Steenhaut & J. Tiberghien - VUB

SDH Rings 34 10 -05 -K. Steenhaut & J. Tiberghien - VUB

SDH Rings 34 10 -05 -K. Steenhaut & J. Tiberghien - VUB

SDH Rings 35 10 -05 -K. Steenhaut & J. Tiberghien - VUB

SDH Rings 35 10 -05 -K. Steenhaut & J. Tiberghien - VUB

SDH Rings The MCI Belgian Network 36 10 -05 -K. Steenhaut & J. Tiberghien

SDH Rings The MCI Belgian Network 36 10 -05 -K. Steenhaut & J. Tiberghien - VUB

SDH Rings CUT ! 37 10 -05 -K. Steenhaut & J. Tiberghien - VUB

SDH Rings CUT ! 37 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 38 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Telephone Exchange (Conceptual Model) trunk lines + Inter-office signaling Line Circuit Register Line Circuit

Telephone Exchange (Conceptual Model) trunk lines + Inter-office signaling Line Circuit Register Line Circuit Switching Matrix Register Control Computer 39 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Signaling system generations • SS 1 - SS 5 : Analog call forwarding between

Signaling system generations • SS 1 - SS 5 : Analog call forwarding between exchanges • SS 6 : First digital signaling system – monolithic communications system (no layers) – Full mesh of virtual circuits, based on 2400 b/s links • SS 7 : 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 ? ? ? 40 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Telephone Network Non-geographic Numbering 6234567 4776970 477 database 0800 62 X 538 6736476

The Telephone Network Non-geographic Numbering 6234567 4776970 477 database 0800 62 X 538 6736476 643 629 64 X 6292905 41 6433180 0800 12345 10 -05 -K. Steenhaut & J. Tiberghien - VUB

The Telephone Network Number portability Ported numbers 42 10 -05 -K. Steenhaut & J.

The Telephone Network Number portability Ported numbers 42 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access

Contents • Traditional Overall structure – Access network » Fixed lines » Wireless access • GSM • UMTS – Trunk network » Primary multiplexing : E 1 / T 1 lines » Higher order multiplexing • Plesiochronous Data Hierarchy • Synchronous Data Hierarchy – Exchanges and signaling • General purpose SDH networks 43 10 -05 -K. Steenhaut & J. Tiberghien - VUB

General Purpose SDH Networks PABX 44 PABX 10 -05 -K. Steenhaut & J. Tiberghien

General Purpose SDH Networks PABX 44 PABX 10 -05 -K. Steenhaut & J. Tiberghien - VUB

Bibliography To know More about Telephony John C. BELLAMY Digital Telephony Third edition John

Bibliography To know More about Telephony John C. BELLAMY Digital Telephony Third edition John Wiley, 2000. ISBN : 0 -471 -34571 -7 Recommended for this chapter 45 10 -05 -K. Steenhaut & J. Tiberghien - VUB