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SUMMER TRAINING REPORT Taken At BSNL.

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INDEX

1. INTRODUCTION

2. OPTICAL FIBRE COMMUNICATION(O.F.C.)

3. G.S.M.

4. C.D.M.A.

5. BROADBAND

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B.S.N.L. – An Introduction:-

Bharat Sanchar Nigam Limited (known as BSNL, India Communications Corporation Limited) is a state-owned telecommunication

company in India. BSNL is the sixth largest cellular service provider, with over

57.22 million customers as of December 2009 and the largest land line telephone provider in India.

Its headquarters are at Bharat Sanchar Bhawan, Harish Chandra Mathur Lane, Janpath, New Delhi. It has the status of Mini Ratna, a status assigned to reputed public sector companies in India.

BSNL is India's oldest and largest Communication Service Provider (CSP). Currently has a customer base of 90 million as of June 2008. It has footprints throughout India except for the metropolitan cities of Mumbai and New Delhi which are managed by MTNL.

As on March 31, 2008 BSNL commanded a customer base of 31.55 million Wireline, 4.58 million CDMA-WLL and 54.21 million GSM services.

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OPTICAL FIBRE COMMUNICATION

1)FIBRE OPTICS SYSTEM

2)FIBRE TYPES

3)OPTICAL FIBRE PARAMETERS

4)ADVANTAGES

5)APPLICATIONS

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1)FIBRE OPTICS SYSTEM:-

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Optical Fiber

Provides physical connectivity between two ends using light as a communication mechanism◦ Uses “Total Internal Reflection” principle

to propagate light through the fiber Composed of long and thin strands of

pure glass about the diameter of human hair – arranged in bundles

Three significant components:◦ Core – Glass center where light travels◦ Cladding – Material that reflects light

back into Core◦ Buffer Coating – Plastic coating that

protects fiber from damage and moisture

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Optical Fiber (2): Types

Single-Mode (Yellow Cable; expensive)◦ They have small cores (about 3.5 x 10-

4 inches or 9 microns in diameter) and transmit infrared laser light (wavelength = 1,300 to 1,550 nanometers)

◦ Carrier owned fiber used for Wide Area Networks with relatively large distances (20 to 30 miles) before a regenerator is required to go further

Multi-Mode (Orange Cable; inexpensive) ◦ They have larger cores (about 2.5 x 10-

3 inches or 62.5 microns in diameter) and transmit infrared light (wavelength = 850 to 1,300 nm) from Light-Emitting Diodes (LEDs)

◦ Customer owned fiber used for Metropolitan Area Networks with relatively short distances between ends

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PRINCIPLE:

ø1

Angle of incidence

n1

n2

ø2

n1

n2

ø1

ø2

n1

n2

ø1 ø2

Angle ofreflection

Light is bent away from normal

Light does not enter second material

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PROPAGATION OF LIGHT THROUGH FIBRE:

The optical fibre has two concentric layers called the core and the cladding. The inner core is the light carrying part. The surrounding cladding provides the difference refractive index that allows total internal reflection of light through the core. The index of the cladding is less than 1%, lower than that of the core. Typical values for example are a core refractive index of 1.47 and a cladding index of 1.46Jacket

CladdingCore

Cladding

Angle of reflection

Angle of incidence

Light at less thancritical angle isabsorbed in jacket

Jacket

Light is propagated by total internal reflection

Jacket

Cladding

Core

(n2)

(n2)

Fig. Total Internal Reflection in an optical Fibre

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FIBRE TYPES:

There are three types of fibres :

(I) Multimode Step Index fibre (Step Index fibre)

(II)Multimode graded Index fibre (Graded Index fibre)

(III) Single- Mode Step Index fibre (Single Mode Fibre)

OPTICAL FIBRE PARAMETERS:(1)WAVELENGTH

(2)FREQUENCY

(3)ATTENUATION

(4)BANDWIDTH

(5)NUMERICAL APERTURE

(6)DISPERSION

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ADVANTAGES:

• SPEED: Fiber optic networks operate at high speeds - up into the gigabits

• BANDWIDTH: large carrying capacity• DISTANCE: Signals can be transmitted

further without needing to be "refreshed" or strengthened.

• RESISTANCE: Greater resistance to electromagnetic noise such as radios, motors or other nearby cables.

• MAINTENANCE: Fiber optic cables costs much less to maintain.

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APPLICATIONS:

Optical fiber is also used extensively for transmission of data. Multinational firms need secure, reliable systems to transfer data and financial information between buildings to the desktop terminals or computers and to transfer data around the world. Cable television companies also use fiber for delivery of digital video and data services. The high bandwidth provided by fiber makes it the perfect choice for transmitting broadband signals, such as high-definition television (HDTV) telecasts. Intelligent transportation systems, such as smart highways with intelligent traffic lights, automated tollbooths, and changeable message signs, also use fiber-optic-based telemetry systems.

Another important application for optical fiber is the biomedical industry. Fiber-optic systems are used in most modern telemedicine devices for transmission of digital diagnostic images. Other applications for optical fiber include space, military, automotive, and the industrial sector.

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G.S.M.(GLOBAL SYSTEM FOR MOBILE COMMUNICATION):

Definition:- GSM (Global system for mobile communication) is a cellular network, which means that mobile phones connect to it by searching for cells in the immediate vicinity.

GSM divided into 3 major system:-

Mobile Station Subsystem(MSS)

Base Station Subsystem (BSS):- Base transceiver station (BTS) Base Station controller (BSC)

Network Switching system (NSS):- Mobile switching center Home location registers Visitor location registers Authentication center Equipment identity registers

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Structure of GSM:-

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Generations in GSM:-

1 G 2 G 2.75 G 3 G 3.5 G 4 G

CONFIGURATION:-- Frequency allocation: 890 – 915 MHz mobile to base station 935 – 960 MHz base station to mobile FDD system (frequency division duplex)-Choice of digital signals- Integration of voice, data and signalling- Spectral efficiency- High quality- Low cost terminals

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CDMA(CODE DIVISION MULTIPLE ACCESS):-

What is CDMA? “Code Division Multiple Access (CDMA) is a digital

cellular spread-spectrum modulation technique that implements distributed voice and data networks”.

“CDMA uses codes to convert between analog voice

signals and digital signals.”

The various technological options available are as follows :

1. Multi Access Radio Relay 2. Wireless In Local Loop 3. Fibre In the Local Loop

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CDMA ACCESS-A CONCEPT:

WIRELESS IN LOCAL LOOP

Less (Optimum) Power per cell

Seamless Hand-off

No Frequency Planning:

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Hand Offs in CDMA:

SoftHard and Idle.

CDMA frequency- reuse planning (cellular concept):

Each BTS in a CDMA network can use all available frequencies. Adjacent cells can transmit at the same frequency because users are separated by code channels, not frequency channels. BTSs are separated by offsets in the short PN code This feature of CDMA, called "frequency reuse of one," eliminates the need for frequency planning.

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BROADBAND TECHNOLOGY:-

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WIRED LINE TECHNOLOGIES INCLUDE

Digital Subscriber Lines (DSL) on copper loop.Optical Fibre Technologies.Cable TV Networks.PLC (power line communication).

WIRELESS TECHNOLOGIES INCLUDE:Satellite MediaTerrestrial Wireless3G MobileWi-Fi (wireless Fidelity)Wi Max.FSO (free space optics).

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What is WiMax?

WiMax (Worldwide Interoperability for Microwave Access) is a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL.

The technology is specified by the Institute of Electrical and Electronics Engineers Inc., as the IEEE 802.16 standard.

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Wi-Fi: The Predecessor of WiMax

Wi-Fi (Wireless Fidelity) is a set of technologies that are based on the IEEE 802.11a,b, and g standards.

Wi-Fi is considered to be one of the first widely deployed fixed broadband wireless networks.

The Wi-Fi architecture consists of a base station that wireless hosts connect to in order to access network resources.

As long as the users remain within 300 feet of the fixed wireless access point, they can maintain broadband wireless connectivity.

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Relation of Wi-Fi and WiMax

WiMax eliminates the constraints of Wi-Fi.Unlike Wi-Fi, WiMax is intended to work

outdoors over long distances.WiMax is a more complex technology and

has to handle issues of importance such as QoS guarantees, carrier-class reliability, NLOS.

WiMax is not intended to replace Wi-Fi. Instead, the two technologies complement each other.

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WiMax Applications

According to WiMax Forum it supports 5 classes of applications:

1. Multi-player Interactive Gaming.2. VOIP and Video Conference3. Streaming Media4. Web Browsing and Instant Messaging5. Media Content Downloads

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WiMax Advantages in a Nutshell

Robust, reliable carrier class “last-mile” technology with QoS

For many types of high-bandwidth applications- at the same time, across long distances

Enabling new applications that improve daily life

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Conclusions

It is expected that WiMax becomes the dominant standard for Wireless MAN in the world market, at least, in fixed broadband networks.

WiMax products will have to be delivered to the market needs and those for the end-users will have to be extremely easy to install.

Focus is too often on technologies– Subscribers pay for services, not technologies– Technologies enable services, but should not be a burden on

users– Broadband capabilities are important, but bandwidth is not the

only meter to assess service– Hence telecomm. Sector has changed our lifestyle today

entirely and today it seems that world has become very small.

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THANK YOU