body third generation of fiber optic communication systems

Executive Summary

The world has entered a new era of communication technology We are facing challenges of the twenty-first century Technologies are improving day by day Optical fiber technology is the most advanced technology in communication system Fiber optic communication is being currently used in telephone submarine cable and special security and alarm systems electronic instrumentation systems medical systems satellite ground stations industrial automation and process controls Communication engineers have always dreamt of higher information bandwidth with low attenuation and cost Moreover fiber is not affected by electromagnetic interference power surges or lightning For these reasons communication engineers have chosen Optical fiber for network purposes as transmission medium Moreover for high speed and longer distances local area networks (LANs) are based on Fiber optics So it was decided to study the Optical fiber communication system Some other reasons are given below- Exploit the enormous bandwidth of an optical fiber

To utilize the available optical bandwidth (THz) by different users

- Increase the transmission capacity

Due to limitations imposed by dispersion and nonlinear effects transmission rate per channel lt 10

Gbs

- Resource sharing

To share the same optical fiber channel and equipment by a number of users

- Reduce the overall transmission cost per channel

Page | 1

Chapter-One Introduction 11 Introduction

In Bangladesh application of Optical fiber as communication links has already been started The introduction of optical fiber communication system into the public network has stimulated investigation and application of the transmission techniques by public utility organizations which provide their own communication facilities over moderately long distances SONET (Synchronous Optical Network) or SDH(Synchronous Digital Hierarchy) as its known in Europe is a set of standards for interfacing Operating Telephone Company(OTC) optical networksThey are a set of global standards for interfacing equipment from different vendors (One of the few where telephony is concerned)

SONET is the protocol for North America and Japan while SDH is the definition for Europe The differences between SONET and SDH are slight

12 Background of the study

MBA project report is an attempt to provide business students an orientation to a real life business situation in which we can observe and evaluate the use and applicability of the theoretical concepts As per norm this report is the requirement of the fulfillment of the MBA program This report ldquoThird Generation Fiber Optic Communication Systemsrdquo is the outcome of 4 weeks works on Communication Sector During this period my job has related to this department My honorable supervisor is Dr Muhammad Shariat Ullah Assistant Professor of Dhaka International University The authorized this report to me to acquire the practical knowledge

With some 1200 million telephone connections in use today and the number of Internet users growing rapidly network providers must deal effectively with increased telephone traffic In response several methods and technologies have been developed within the last 50 years to address these market needs as economically as possible Then communications engineers introduced frequency division multiplex (FDM) systems that modulated each individual telephone channel with a different carrier frequency The signals could then be shifted into different frequency ranges to transmit several telephone connections over a single cable

The advent of semiconductor circuits and a continuing demand for telephone capacity in the 1960s resulted in the development of the pulse code modulation (PCM) transmission method

With PCM (using a single line multiple times through digital time-domain multiplexing) the analog telephone signal is first sampled at a 31 kHz bandwidth quantized and encoded and then transmitted at a 64 kbps rate Collecting 30 such coded channels together into a frame along with the necessary signaling information can achieve a 2048 kbps transmission rate

Page | 2

13 Objectives of the study

The specific objective of this report includes

1048713 All basic concepts which are necessary to interact with SDH experts or to understand fully the technical documentation of SDH systems 1048713 Basics of optical transmission systems (WDM OTDM) 1048713 Advantages and drawbacks of PDH and SDH systems 1048713 Operation principles of PDH and SDH with emphasis on practical aspects 1048713 the SDH frame structure pointer justification mechanism overhead and multiplexing schemes 1048713 Functions and system-level description of SDH equipment (regenerators terminal and add-drop multiplexers digital cross-connects) 1048713 Several examples of network applications of SDH equipment 1048713 SDH networks architectures 1048713 Traffic protection and restoration in SDH networks 1048713 Techniques for broadband data transport over SDH (ATM IP VCAT LCAS GFP GbE) 1048713 Other aspects relevant to the design and operation of SDH transmission networks such as SDH network synchronization management and testing (in laboratory and on field)

14 Scope of the study

There are so many communication systems in Bangladesh MetroNet Bangladesh Ltd is one of them It is a Fiber optic communication systems compare than others There are only three Communication systems engineers works There are above 450 labors and 40 staff works here Though the organization is not so big and all related department situated in one building so that I can easily identify the person who had hold the relevant information needed to my study and collected data from engineer and other staffs ( Labors and officers) and management team of various department

The development of optical fiber transmission and large-scale integrated circuits made more complex standards possible There are demands for improved and increasingly sophisticated services that required large bandwidth better performance monitoring facilities and greater network flexibility

15 Methodology

01 Primary source The primary information collected various Third Generation Fiber Optic Communication Systems report

- Different Lecture sheet of Prof Dr S P Majumder02 Secondary Source

Organizational report

Web site Information

Different files of the company

Page | 3

Information Source

Transmitter X-mission Medium

Receiver (Demodulation)

Destination

Information Source Electrical Transmitter Optical Source Optical Fiber Cable

DestinationElectrical ReceiverOptical detector

141 Comparison between Conventional Communication Systems and Optical Fiber Communication Systems

The block diagram of general communication system and optical fiber communication system is shown in fig bellow

Figure 31 (a) Conventional communication system

Figure 31 (b) Optical fiber communication system

In a conventional communication system the information source provides an electrical signal to a transmitter which converts the signal into a suitable form for propagation over the transmission medium The transmission medium may consist of amiddot pair of wires a coaxial cable or a radio link through free space down which the signal is transmitted to the receiver where it is transformed into the being passed to the destination In this communication system the information is attenuated in the transmission medium

For optical fiber communication system the information source provides an electrical signal to a transmitter comprising an electrical stage which drives an optical source to give modulation of light wave currier The optical source which provided the electrical conversion may be either a semiconductor laser or LED The transmission medium consists of an optical detector which drives a further electrical stage and hence provides demodulation for detection of the optical signal or the optical electrical conversion In this communication system attenuation is negligibly small

142 Advantage of optical fiber communicationSeveral advantages come with taking the fiber optics route

bull High Bandwidth ~ 1014 Hz bull Low signal attenuation lt 02 dBkmbull Low signal distortionbull Low power requirement bull Low material usagebull Small space requirementbull Low cost In addition to the advantages of having extra information bandwidth using like as the carrier

signal the optical fiber communication system have several other advantages over the conventional systems

Page | 4

143 Disadvantage of optical fiber communication Highly skilled staff would be required for maintenance

a) Only point to point working is possible on optical fiberb) Precise and costly instruments would be requiredc) Costly if under utilizedd) Accept unipolar codes onlye) Jointing of fiber and splicing is also time consuming

16 Limitations

1 There exist no worldwide standard except for regional digital signals and frame structures2 Therefore it no flexible network topology 3 Has low utilization of digital equipment and4 Provides no optimal routing5 Multiplexing structure based on point to point transmission

Page | 5

Chapter-Two SDH Background

21 Historical Perspective 211 First Generation Systems

bull Deployed in 1977

bull Used multimode fiber near 850 nm wavelength

bull Suffer from severe limitations

bull attenuation (2dBkm)

bull chromatic dispersion

bull multimode dispersion

bull bit rate 45 Mbps

repeater spacing 10 km

212 Second Generation Systems

introduced in the 1980rsquos

avoid chromatic dispersion by operation at 1300 nm

it has low attenuation of 1 dBkm

use multimode fiber

o suffer from modal dispersion

o bit rate 45 Mbs

o repeater spacing 30 km

213 Third Generation Systems

bull deployed in the mid- 1990rsquos

bull operating at 1300 nm wavelength

bull use single-mode fiber

bull avoid modal dispersion

bull bit rate 1 Gbs

bull repeater spacing 40 km

bull suffer from transmission losses

bull attenuation (lt 1 dBkm)

Page | 6

214 Fourth Generation Systems

bull introduced in 1995

bull operate at 1500 nm wavelength

bull low attenuation (lt 03 dBkm)


bull bit rate 10 Gbs


Still suffer from chromatic dispersion

215 Fifth Generation Systems

bull utilize dispersion shifted and flattened fibers

bull use optical amplifiers and WDM systems

bull dispersion managed fibers

bull attenuation lt 02 dBkm

bull repeater spacing 1000km

bull bit rate 10 ndash 50 Gbs

bull optical solution system

bull balance between dispersion and non-linearity

Page | 7

Chapter-Three SDH Functions31 Definition of SDH

Communications networks gradually converted to digital technology after PCM was introduced in the 1960s A multiplex hierarchy known as plesiosynchronous digital hierarchy (PDH) evolved to cope with the demand for ever-higher bit rates The bit rates start with the basic multiplex rate of 2 Mbps with further stages of 8 34 and 140 Mbps In North America and Japan however the primary rate is 15 Mbps with additional stages of 6 and 44 Mbps as shown in Figure 1 on page 5 This fundamentalDevelopmental difference made gateway setup between the networks both difficult and expensiveIn response to the demand for increased bandwidth reliability and high-quality service SDH developed steadily during the 1980s eliminating many inherent disadvantages in PDH In turn network providers began to benefit from the many technological and economic advantages this new technology introduced as discussed in this section

311 High transmission rates Transmission rates of up to 10 G can be achieved in modern SDH systems making it the most suitable technology for backbones the superhighways in todayrsquos telecommunications networks

312 Simplified add and drop function Compared to the older PDH system low-bit-rate channels can be easily extracted from and inserted into the high-speed bit streams in SDH eliminating the need for costly demultiplexing and re-multiplexing the plesiosynchronous structure

313 High availability and capacity matching SDH enables network providers to react quickly and easily to their customersrsquo requirements such as switching leased lines in just minutes Network providers can use standardized network elements (NE) that they can control and monitor from a central location with a telecommunications management network (TMN) system

314 ReliabilityModern SDH networks include various automatic backup-circuit and repair mechanisms that management can monitor to cope with system faults so that link or NE failures do not lead to an entire network failure

315 Future-proof platform for new services SDH is the ideal platform for a wide range of services including POTS ISDN mobile radio and data communications such as LAN and WAN It can also handle more recent services such as video on demand and digital video broadcasting via ATM

This tutorial course provides a thorough overview on several topics that are usually not presented in a single book neither in any competing course on SDH In particular we shall learn

1048713all basic concepts which are necessary to interact with SDH experts or to understand fully the technical documentation of SDH systems

1048713basics of optical transmission systems (WDM OTDM)

1048713advantages and drawbacks SDH systems

1048713operation principles of SDH with emphasis on practical aspects

1048713the SDH frame structure pointer justification mechanism overhead and multiplexing schemes

Page | 8

1048713functions and system-level description of SDH equipment (regenerators terminal and add-drop multiplexers digital cross-connects)

1048713several examples of network applications of SDH equipment

1048713SDH networks architectures

1048713traffic protection and restoration in SDH networks

1048713techniques for broadband data transport over SDH (ATM IP VCAT LCAS GFP GbE)

1048713other aspects relevant to the design and operation of SDH transmission networks such as SDH network synchronization management and testing (in laboratory and on field)

Page | 9

Chapter-Four Network analysis

Network Generic Applications

41 Evolutionary Pressures

The need to reduce network operating costs and increase revenues were the drivers behind the introduction of SDH The former can be achieved by improving the operations management of networks and introducing more reliable equipment SDH scores high on both Increase in revenues can come from meeting the growing demand for improved services including broadband and an improved response such as greater flexibility and reliability of networks For broadband services typically based on ATM a number of techniques exist for high-quality routing over PDH networks The characteristics of SDH however make it much more suitable for this application because it offers better transmission quality enormous routing flexibility and support for facilities such as path self-healing

SDH and ATM provide different but essentially compatible features both of which are required in the network

42 Operations

Managing capacity in the network involves such operations as the following

a Protection for circuit recovery in millisecondsb Restoration for circuit recovery in seconds or minutesc Provisioning for the allocation of capacity to preferred routesd Consolidation or the funneling of traffic from unfilled bearers onto fewer bearers in order

to reduce waste of traffic capacitye Grooming or the sorting of different traffic types from mixed payloads into separate

destinations for each type of traffic

43 Bit Rates

421 Bit RatesOptical Level Electrical Level Line Rate (Mbps) SDH EquivalentOC-1 STS-1 5184 ---OC-3 STS-3 155520 STM-1OC-9 STS-9 46656 STM-3OC-12 STS-12 622080 STM-4OC-18 STS-18 933120 STM-6OC-24 STS-24 1244160 STM-8OC-36 STS-36 1866240 STM-13OC-48 STS-48 2488320 STM-16OC-96 STS-96 4976640 STM-32OC-192 STS-192 9953280 STM-64

Page | 10

422 International organization defined standardized bit rates

44 SDH Features and Management441 Traffic Interfaces

SDH defines traffic interfaces that are independent of vendors At 155 Mbps they are defined for both optical and copper interfaces and at higher rates for optical ones only These higher rates are defined as integer multiples of 15552 Mbps in an n x 4 sequence giving for example 62208 Mbps(622Mbps) and 248832Mbps(25Gbps) To support network growth and the demand for broadband services multiplexing to even higher rates such as 10 Gbps continues in the same way with upper limits set by technology rather than by lack of standards as was the case with PDH

442 SDH Layers

In the multiplexing process payloads are layered into lower-order and higher-order virtual containers each including a range of overhead functions for management and error monitoring Transmission is then supported by the attachment of further layers of overheads This layering of functions in SDH both for traffic and management suits the layered concept of a service-based network better than the transmission-oriented PDH standards

443 Management Functions

To support a range of operations SDH includes a management layer whose communications are transported within dedicated data communications channel (DCC) time slots inside the interface rate These have a standard profile for the structure of network-management messages irrespective of vendor or operator However there has been no agreement on the definition of the message sets to be carried so there is no interworking of management channels between equipment vendors at the SDH interface

Page | 11

444 Standard Frame Representation

Everywhere in the world the standard SDH frameRepresentation is a MATRIX with 9 rows

Page | 12

45 SDH Frame Structure451 Outline

The frame has a repetitive structure with a period of 125 microseconds-the same as for pulse code modulation (PCM)-and consists of nine equal-length segments At the gross transport rate of 15552 Mbps for the base synchronous transport module (STM-01) there is a burst of nine overhead bytes at the start of each segment as shown at the top figure 5 This figure also depicts how the SDH frame at STM -1 is conventionally represented with the segments displayed as from nine rows and 270 columns Each byte is equivalent to 64 kbps so eac column of nine bytes is equivalent to 570 kbps

452 SDH Frame structure

All SDH frames have the same structure

4421 Transport Overhead SOH

Page | 13

bull Transport Overhead AU 4 pointer

Page | 14

In order to illustrate the pointer working

We have exactly the same phenomenon in SDH

46 SDH Multiplexing

Page | 15

SDH is a new way of multiplexing slow signals onto a faster signal It has mechanisms for dealing with tributaries that are not running at the same clock rate

Translation of the previous picture in SDH language

461 The SDH Multiplexing map

Page | 16

47 Equipment471 Optical cross-connect

Optical cross-connects are known in the united states as digital cross-connect switches (DCCs) and as DXCs elsewhere They are classified as DCSpq or DXC pq where p is the traffic component that is switched within that port bit rate

Some cross-connect designs allow all traffic interfaces to be in PDH form for compatibility with existing equipment In particulars these designs might allow the p hierarchcal level in a DXC pq cross-connect to be at either 34 or 140 Mbps in PDH format as an alternative to 155 Mbps so that network flexibility becomes available where SDH infrastructure does not yet exist In these cross-connects a port at 34 or 140 Mbps can include an embedded PDH multiplex equipment for internal conversion to and from 2 mbps which provides a trans-multiplexer function between PDH and SDH area of the network

472 Virtual Containers

At each level subdivisions of capacity can float individually between the payload areas of adjacent frames This individuation allows for clock differences and wandering as payloads traverse the network and are interchanged and multiplexed with others In this way the inevitable imperfections of network synchronization can be accommodated Each subdivision can be readily located by its own pointer that is embedded in the overheads The pointer is used to find the floating part of the AU or TU which is called a virtual container (VC) The AU pointer located a higher-order VC and the TU pointer located a lower-order VC For example an AU-3 contains a VC-3 plus a pointer and a TU-2 contains a VC-2 plus a pointer

48 Cable lay-out method

At the time of making trench lay-out it should be taken in mind the position of bridge and bend road The splicing point should be given considering this point The two sides of the bridge there should be placed handhold and splicing point The distance between two handhold and splicing point should be declarer in meter in the drawing The line will be marking by line and straight The position of underground cable and railway office their lay-out plans

481 Cable Installation

Page | 17

The optical Fiber cable has been made by blowing machine at the time of blowing A man should be kept the front handhold 25m cable should be kept in the handhold and 30m cable should be kept where the splicing point For beginning the next blowing the blowing machine should be placed next the handhold function will be method

Reading of the cable should be recorded at the closure terminal at splicing loss more then o3 will be taken At the time of splicing the joint point will have to heating by giving heat will smove The fiber will have to arrange fairly in cloggier tray If the fiber number is 12 then they have separate by 6 in each arrangement If this work functions for 48 fibers will have to finish The trench will have to kept between two closure and heaved to kept fairly by closure rubber band The point of closure has to close by heating They indicate the direction of cable by arranging circle order in the handhold ammoniating striker have to given and at last the open path of the handhold will have to close by the handhold key

482 List of the Instruments

1 Blowing machine2 Optical fiber cable3 Splicing machine4 OTDR5 Power Meter6 Laser Gun7 Closure8 Smove9 SDH MUXDMUX

Network Coverage MAP in CAD

1 Over all MAP2 Distribution MAP in CAD3 Back Bone MAP in CAD

Over all MAP

Page | 18

Distribution MAP in CAD

Back Bone MAP in CAD

Page | 19

Optical-fiber-joint-enclosure

Chassis Media Converter For MonitoringPOP end

Client End

POP End Status

Page | 20

Client Status

Monitoring Server

Page | 21

Final Checking in Field

When the lying of the cable is complete next important point is to check weather there is any loop This is done by passing laser beam from one tower to another If there are us any leakage or loss or any other technical problem is easily detected by this method

01 Splicing Machine 02 Splicing Machine and tray

Page | 22

03 Optical Fiber Rack 04 O T D R

49 Network Topology

The flexibility of SDH can be used to best advantage by introducing a new network topology Traditional networks make use of mesh and hub( ie start) arrangements but SDH with the help of DXCs and hub multiplexers allows these to be used in a much more comprehensive way SDH also enables these arrangement to be combined with rings and chains of ADMs to improve flexibility and reliability across the core and access of a network

491 Network Block Diagram

Page | 23

492 NOC Block Diagram

493 POP End Distribution Block Diagram

Page | 24

Chapter ndashFive Conclusion and recommendation

51 Conclusion

The main disadvantage of fiber optic cables is their cost Expensive to install and more fragile than their metal counterparts fiber optic cables are difficult to split as well This makes them more difficult to work with and install onsite some optical fibers are subjected to fiber fuse an occurrence caused when too much light reaches an imperfection in the line that destroys connectivity Fiber fuse can be minimized with defection circuitry at a transmitter Some fiber optic cables also cant carry electrical power to operate terminal devices buit this feature is becoming passes with the wider availability of mobile phones wireless PDAs and other remote devices

- Access to the fiber-optic submarine cable network will have an evolutionary impact on the development of information and communication Technology (ICT) sector in Bangladesh The most important and remarkable impacts are

- Almost free access to the global ICT resources and server network in the advanced countries at a gigabit transmission rate

-- Radical development in economy human resources development education health and medical services and business

- Fast internet access through mobile network which will provide mobile internet facilities

- Support to mobile banking e-shopping e-commerce e-education e-health and telemedicine etc

- Support to telecommunication infra-structure for e-governance

Although we get some disadvantages Optical communication Such as

1 The flexibility of the base fibers2 Some problems involved with joining low T-couplers3 Some doubt in relation to the long-term reliability of optical fiber in the presence of

moisture4 The small size of the fibers amp cables which creates some difficulties with splicing amp

forming connector 5 An independent electrical power feed is required for any repeaters etc

But the technology has developed So both continuing developments and experience with optical fiber system are generally reducing these problems

Page | 25

52 Recommendation

- To provide infrastructure for the submarine cables optical fiber should be established in phases throughout the country

- Additional people should be employed and they should be well trained on optical communication system its maintenance and repairing

- Sophisticated repair equipments need to be imported Workshops should be improvised To exploit the full bandwidth of FON capacity

We are now at the peak of the century of technology and communication We should think about the easiest and noiseless communication technology In this purpose the optical fiber communication system has made a tremendous change in the field of data communication system although it is not familiar in our country but it is hopeful that optical fiber is being introduced gradually An optical fiber is allowing us with its Terabyte standard speed in data communication So we have no other choice like fiber optics comparing with coaxial cable Our neighboring country India has made a great development in the field of communication technology by introducing fiber optics backbone network recently We should also be able to develop our communication system to a world standard by familiarizing Optical fiber in our country We may change the status by improving fiber optic technology

Page | 26

Bibliography

I Pollob Mohaimen ldquoOboes-E-Submarine Cable-E Bangladeshrdquo The Daily Newspaper Prothom alo (In Bangla) Friday May 21 2004

II Choudhury JR A Presentation on Prospects of Information and Communication Technology (ICT) of Bangladesh in DSCSC July 25 2005

III Mujibur Rahman Md The Role of BTTB to facilitate the growth of ICTs in Bangladesh TELETECH May 2004 P 56

IV Barta Correspondent 100 Mbps Data Transfer in Dhaka Monthly Computer Barta July 2004 p 31

V A Souvenir published by Bangladesh Computer Council on 28 July2005 P-26

VI Jahangir Alam Submarine Cable and Bangladesh Monthly Computer Tomorrow April 2004 p 34

Page | 27

Chapter-One Introduction 11 Introduction

In Bangladesh application of Optical fiber as communication links has already been started The introduction of optical fiber communication system into the public network has stimulated investigation and application of the transmission techniques by public utility organizations which provide their own communication facilities over moderately long distances SONET (Synchronous Optical Network) or SDH(Synchronous Digital Hierarchy) as its known in Europe is a set of standards for interfacing Operating Telephone Company(OTC) optical networksThey are a set of global standards for interfacing equipment from different vendors (One of the few where telephony is concerned)

SONET is the protocol for North America and Japan while SDH is the definition for Europe The differences between SONET and SDH are slight

12 Background of the study

MBA project report is an attempt to provide business students an orientation to a real life business situation in which we can observe and evaluate the use and applicability of the theoretical concepts As per norm this report is the requirement of the fulfillment of the MBA program This report ldquoThird Generation Fiber Optic Communication Systemsrdquo is the outcome of 4 weeks works on Communication Sector During this period my job has related to this department My honorable supervisor is Dr Muhammad Shariat Ullah Assistant Professor of Dhaka International University The authorized this report to me to acquire the practical knowledge

With some 1200 million telephone connections in use today and the number of Internet users growing rapidly network providers must deal effectively with increased telephone traffic In response several methods and technologies have been developed within the last 50 years to address these market needs as economically as possible Then communications engineers introduced frequency division multiplex (FDM) systems that modulated each individual telephone channel with a different carrier frequency The signals could then be shifted into different frequency ranges to transmit several telephone connections over a single cable

The advent of semiconductor circuits and a continuing demand for telephone capacity in the 1960s resulted in the development of the pulse code modulation (PCM) transmission method

With PCM (using a single line multiple times through digital time-domain multiplexing) the analog telephone signal is first sampled at a 31 kHz bandwidth quantized and encoded and then transmitted at a 64 kbps rate Collecting 30 such coded channels together into a frame along with the necessary signaling information can achieve a 2048 kbps transmission rate

Page | 2







15 Methodology






Page | 3

Information Source



Destination












Page | 4



16 Limitations


Page | 5















use multimode fiber


o bit rate 45 Mbs







bull bit rate 1 Gbs




Page | 6


















Page | 7














Page | 8







Page | 9






42 Operations





43 Bit Rates


Page | 10




442 SDH Layers




Page | 11



Page | 12






Page | 13


Page | 14



46 SDH Multiplexing

Page | 15




Page | 16









Page | 17







Over all MAP

Page | 18



Page | 19



Client End

POP End Status

Page | 20

Client Status

Monitoring Server

Page | 21




Page | 22


49 Network Topology



Page | 23



Page | 24


51 Conclusion













Page | 25

52 Recommendation





Page | 26

Bibliography







Page | 27



Page | 24


51 Conclusion













Page | 25

52 Recommendation





Page | 26

Bibliography







Page | 27


51 Conclusion













Page | 25

52 Recommendation





Page | 26

Bibliography







Page | 27

52 Recommendation





Page | 26

Bibliography







Page | 27

Bibliography







Page | 27

body third generation of fiber optic communication systems

Career