Transmission Overview Tgenovt001

CETTM MTNL

1TRANSMISSION OVERVIEW

TRANSMISSION OVERVIEW

MODULE ID: TGENOVT001

CETTM MTNL


Introduction to Transmission NetworksTransmission Media PCM & Higher Order MultiplexingTransmission SystemsSDH Concepts WDM BasicsMPLS BasicsMLLN

Topics

CETTM MTNL


Signal: Physical magnitude specific for each medium, change with respect to timeTransmission medium: consists of links that connect nodesNodes : Network elements that receive/retransmit further until reaching final usersInformation : Consists message exchanged between final users ,coded as signalsAnalog signal: can take an unlimited number Of values within a given rangeDigital signal: Take limited number of values.

Key Terms

CETTM MTNL


Message signal

Transmitter Medium Receiver Out put

signal

Transmission System Architecture

The telecommunications network transmits a variety of information, in two basic forms, analog or digital from one place to another

CETTM MTNL


Advantages of digital communication

Improved signal to Noise RatioCompatibility of different media,trafficNo additional interference as noiseEconomyNovel facilities and sevicesApplicability in extremely difficult transmission pathsSimpler equipment (no need of filters)Easy repeatability of design.

CETTM MTNL


Digital Transmission Systems

Higher Order Multiplex

Higher Order Multiplex

TERMINAL

TERMINAL

CCITT Interface

CCITT Interface

Media

Line (Coax cable)

Optical fiber

Satellite

Digital Radio

CETTM MTNL


Problems of legacy media

Bandwidth and capacity limitationsAttenuation, cross talk, noise ,distortionElectromagnetic interferenceWire separation limits to achieve distortionless condition in /wire, ug cablesRequirement of filters,line and office repeaters , ccps,(repeater spans 1.5 km in case ug cable pairs, 4.5 km for cxl cablesFading , reflection, absorption ,line of sight problems in case of microwaveHigh initial cost of Satelite, royalty for RF

CETTM MTNL


Microwave System Configuration

Base BandTx Unit

SupervisoryChannels

Modulator UpConverterBRANCHING

UnitDownConverterDemodulator

Tx1

Tx2

Rx2

Rx1

FromMUX

Base BandRx Unit

ToMUX

CETTM MTNL


Classification of O F CableBased on material usedGlass Fiber & Plastic clad Silica

Based on Size or ModeMulti mode - Large core dia..50/62.5/85/100

umSingle mode - Small core dia (8/9/10 um)

Based on Refractive IndexStep Index - Uniform R.I for the coreGraded Index - Non uniform R.I for the core

CETTM MTNL


Frequency division multiplexing

Process of translating individual speech circuits into pre assigned frequency slots within the bandwidth of the transmission medium

CETTM MTNL


TIME DIVISION MULTIPLEXINGTDM Involves Sharing of the Transmission medium by a Number of Circuits in TIME DOMAINThis can be achieved by establishing a sequence of Time Slots (periods) during which Individual channels (circuits) are Transmitted

CETTM MTNL


Modulation

Modulation is the process of varying one waveform in relation to another waveform

Three types of modulation are Analogue modulation Digital modulation Pulse modulation

CETTM MTNL


Modulation of Digital Signal

ASK (Amplitude Shift Keying) FSK (Frequency Shift Keying) PSK (Phase Shift Keying) QAM (Quadrature Amplitude Modulation)ASK:Amplitude Shift Keying)

The amplitude of the carrier is changed with respect to the input digital signal [ 0 or 1 ].Similar to ON/OFF Keying.Causes more errors

CETTM MTNL


Amplitude Shift Key Modulation

CETTM MTNL


Frequency Shift Key, Phase shift keying

CETTM MTNL


Pulse Code Modulation(PCM) Conversion of Analog signal into Digital

Binary format is called PCMStages of PCM: Filtering..................limiting freq band to 4khz Sampling...............PAM sampling 8000/SE

Quantizing.............Assigning quantity to amplitudes read.

Encoding/Decoding Binary conversion Line Coding.............HDB3+/AMI/CMI

CETTM MTNL


Frame & MultiframeFrame The Collection of one sample from each channel

is called a Frame. Total frames :15 Thus the set of first Samples of all channels is

one frame, the set of Second Samples is Second frame, and so on.

The duration of a frame is 125 micro seconds One additional frame to carry sync data(MFAW)Multi frame A group of 16 frames is formed to make a

Multiframe. The duration of a multi frame is 2 milliseconds.

CETTM MTNL


2 Mbps Frame Structure

Signaling information

32 Time slots in 125 s

Frame Alignment Word (FAW)

Samples from Channels 1 to 15 Samples from Channels 16 to 30

0 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 27 28 29 30 31

CETTM MTNL


Multi Frame Structure

Ch 30

Ch 16

S Ch 30

S Ch 15

Ch 15

Ch 2

Ch 1

ALM &

Supy

F15

Ch 30

Ch 16

S Ch 29

S Ch 14

Ch 15

Ch 2

Ch 1FAW

F14

Ch 30

Ch 16

S Ch 18S Ch 3

Ch 15

Ch 2

Ch 1

ALM &

SupyF3

Ch 30

Ch 16

S Ch 17S Ch 2

Ch 15

Ch 2

Ch 1FAWF2

Ch 30

Ch 16

S Ch 16S Ch 1

Ch 15

Ch 2

Ch 1

ALM &

SupyF1

Ch 30

Ch 16

MFAW ALMMFAW

Ch 15

Ch 2

Ch 1FAWF0

B5-B8B1-B4TS31TS17

TS16TS15TS2TS1TS0

CETTM MTNL


Frequency 2048Kbps 50ppm. (HDB3 coded)

Pulse shape All masks of a valid signal conform to the pulse mask given in ITU-T G.703, irrespective of the sign. The value V corresponds to the nominal peak value.

Type of pair Symmetrical pair.

Test load impedance 120 Ohms resistive.

Nom, peak voltage of a mark (pulse) 3.0 V.

Peak voltage of a space (no pulse) 0 0.3 V.

Nominal pulse width 244 ns.

Ratio of the amplitudes of positive and negative pulses at the centre of the pulse interval

0.95 to 1.05

Ratio of the widths of positive and negative pulses at the nominal half amplitude.

0.95 to 1.05

Max. peak to peak jitter at an output port

As per Para 2 / ITU-T Rec. G.823.

2.048 MBPS G.703 INTERFACE

CETTM MTNL


O F System Composition

Fibre Optics Transmission System (FOTS) comprises of the following sub systems

Digital multiplex sub systemOptical line transmission systemCentral supervisory systemTrans multiplexer sub systemAlarm sub systemPower supply sub system

CETTM MTNL


C 12 VC 12 TU 12 TUG 2X 3

X 7

2 Mb

C26.3 Mb VC 2 TU 2X 1

X 7

X 3

C 3 VC 3 TU 3 TUG 334 Mb

C 4 VC 4 AU 4 AUG STM-NX N140 MbX 1

C 3 VC 3 AU 3X 334 Mb

SDH Multiplexing

C111.5 Mb VC 11 TU 11

X 4

SDH Multiplexing

CETTM MTNL


SDH Frame Structure

1

3

5

9

4

270270 Columns (Bytes)

1 9transmitrow by row

RSOH

MSOH

AU Pointer Payload(transport capacity)

RSOH: Regenerator section overheadMSOH: Multiplex section overheadPayload: Area for information transport

CETTM MTNL


SDH System Types

TypesSTM-1 ----

STM-4 ----

STM-16 --

STM-64 --

Bit Rates Chl. Capacity155.520 Mb/s --- 1890 Chls

622.080 Mb/s --- 7560 Chls

2488.32 Mb/s --- 30240 Chls

9953.28 Mb/s --120960 Chls

CETTM MTNL


IntegratedIntegrated

DWDM Mux

G.692G.692

OpenOpen

OTU

G.692G.692155MSDH155MSDH622MSDH622MSDH2.5G SDH2.5G SDH10G SDH10G SDH

PDHPDHIP

ATMATM

155MSDH155MSDH622MSDH622MSDH2.5G SDH2.5G SDH10G SDH10G SDH

PDHPDHIP

ATMATM

DWDM System inputTransponderTransponder

CETTM MTNL


Mainframe

Mainframe

Server

Server

Storage

Storage ESCON/FICON

Metro DWDM

DWDM Application for Data Centre

Data Centre Interconnection

Fiber Channel

Storage Area Network (SAN ) on DWDM

CETTM MTNL


Basic Working Process of MPLS

Core LSR

IP IP L1 IP L2 IP L3 IP

Traditional IP forwarding

Traditional IP forwarding Label forwarding

Edge LSR Edge LSR

CETTM MTNL


Architecture of a MLLN

V-MUX MODEMDACC

Provides fully secure data communication serviceEnd to end circuit creation and monitoringcircuit loop test and fault isolation,Alternate re-routing of traffic,Software programmability of NTUsFully Managed Access Network

CETTM MTNL


MLLN Network

DACC

DACC

DACC

V-MUX

V-MUX CUSTOMER

CUSTOMER

CETTM MTNL


Summary We have seen different Transmission Technologies and media

Transmission is in transition phase where we are migrating from circuit switching technologies like SDH to Packet switching technology like MPLS Future transmission system will be based on optical switching like OTN ( Optical Transport Networks )

Slide 1Slide 2Slide 3Slide 4Slide 5Slide 7Slide 8Slide 9Slide 13Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 28Slide 29Slide 30Slide 31Slide 33Slide 34Slide 35Slide 37Slide 38Slide 39

Documents

Transmission Overview Tgenovt001