ALTTC(BSNL) PPT BY AMBRISH KUMAR SHUKLA

A Summer Training Experience IN ALTTC (BSNL)

PRESENTED BY : UNDER THE GUIDANCE OF:

AMBRISH KUMAR SHUKLA PRATIBHA GUPTA

ECE, FINAL YEAR JTO, ALTTC(BSNL)

1002931012 GHAZIABAD

KIET, GHAZIABAD

ABOUT ALTTC

Advanced Level Telecom Training Centre(ALTTC), Ghaziabad is the apex training institute of BSNL. ALTTC was set up as joint venture of ITU, Geneva, UNDP and the Govt. of India. It imparts excellent training level in the field of Telecom technology.

The training areas cover vast spectrum of topics such as Digital Switching; Mobile Communication: GSM, 3G, CDMA; Data communication and Information Technology: Broadband , Database Administration, Server Administration; Optical Network and Telecom Network Planning.

TABLE OF CONTENTS

INTRODUCTION OF BROADBANDNEED OF BROADBAND.TYPES OF BROADBAND SERVICES.DIGITAL SUBSCRIBER LINETYPES OF DSL SERVICES.DISCRETE MULTITONE MODULATION.ADSL FREQUENCY SPECTRUM.DSLAM.BROADBAND MARKET SHARE

BROADBAND BROADBAND TECHNOLOGYTECHNOLOGY

INTRODUCTION

The term BROADBAND refers to high speed internet access. It is non specific term. In fact there is no specific international definition for broadband.

As the Internet market continues to grow, demand for greater BW and faster connection speed have led to broadband access to all consumer.

The rapid growth of distributed business application , e-commerce and BW intensive application (such as multimedia , video conferencing and video on-demand ) generate the demand for BW and access network.

NEED OF BROADBANDPROFESSIONAL ACTIVITIES:-

Telecommuting

Video conferencing

Home based business

Home office

ENTERTAINMENT ACTIVITIES:-

Web surfing

Video on-demand

Video games

CONSUMER ACTIVITIES:-

Telemedicine

Distance learning

Information gathering

Photography

Video conferencing among friends and family

DEFINITION

•IN INDIA DOT HAS ISSUED A BROADBAND POLICY IN 2004, KEEPING IN MIND ,BROADBAND CONNECTIVITY IS DEFINED AS-

“A DATA CONNECTION WHICH HAS CAPABILITY OF MINIMUM DOWNLOAD SPEED OF 256 KBPS IS SAID TO BE BROADBAND.”

•IN 2012 NEW NTP WAS ANNOUNCED AND BROADBAND SPEED WAS REVISED TO 2 MBPS IN PLACE OF 256 KBPS.

•PRACTICALLY OBTAINED SPEED IS 56 KBPS.

Types of Broadband Services

WIRED: WIRELESS:

DSL 3G/4G

Cable MODEM Wi-Fi

OFC WiMAX

PLC FSO

DIGITAL SUBSCRIBER LINE (DSL)

DSL is a family of technology that provides high speed Internet access by transmitting digital data over the wires of a local telephone network.

DSL service is delivered simultaneously with wired telephone service on the same telephone line.

DSL uses higher frequency band for data transmission.

The bit rate of consumer DSL service typically ranges from 256 kbps-40mbps in downstream direction depending on DSL technology used ,line condition and service level implementation.

WHY USE DSL

Traditional MODEM can provide data rate upto 56 kbps, to achieve high speed internet access another techniques named DSL was used.

Sampling rate of telephone company =8000 samples /sec . Each sample is represented by 8 bits. One bit is used for control purpose. Hence each sample is effectively represented by 7 bits.

Data rate =8000*7=56000 bits/sec

i.e 56 kbps.

WHERE DSL IS USED

DSL service is used on a local telephone line. As telephone line is twisted pair cable capable of handling BW upto 1.1 MHz. But voice utilizes only 4 KHz BW. So to enhance the efficiency of cable pair , a portion of large BW is utilized for data communication.

Question!

Distance is a limitation for DSL, why it's not also a limitation for voice telephone calls ?

Answer!

The answer lies in small amplifiers called loading coils that the telephone company uses to boost voice signals

these loading coils are incompatible with ADSL signals, so a voice coil in the loop between your telephone and the telephone company's central office will disqualify you from receiving ADSL.

TYPES OF DSL SERVICE

SDSL- Symmetric Digital Subscriber Line

ADSL- Asymmetric Digital Subscriber Line

HDSL- High Bit Rate Digital Subscriber Line

VDSL- Very High Bit Rate Digital Subscriber

Line

Symmetric DSL (SDSL)

UPLOAD SPEED = DOWNLOAD SPEED Upstream= 768 kbps

Downstream= 768 kbps Ex.- Suitable for residential subscriber

who need equal speed in both direction

HDSL AND VDSL

HDSL

Downstream = 1.544 - 2 Mbps

Upstream = 1.544 – 2 Mbps

VDSL

Downstream = 22 – 55 Mbps

Upstream = 3.2 Mbps

Downstream = Upstream = 34 Mbps (If Symmetric)

Asymmetrical DSL (ADSL) ADSL is an asymmetric communication

technology designed for residential users; it is not suitable for businesses.

Downstream data rate is greater than upstream data rate.

Downstream = 1.5 – 8 Mbps

Upstream = 16 – 640 Kbps

MODULATION TECHNIQUE FOR ADSL

1. The modulation technique that is used for ADSL is Discrete Multi tone Modulation (DMT). It combines FDM and QAM.

2. In DMT an available BW of 1.104 MHz is divided into 256 parallel stream . Each parallel stream is known as sub channel or tone or bin or bucket.

3. Each channel uses a BW of 4.312 KHz and can carry maximum 15 bits.

4. Voice – Channel 0

Upstream = Channel 6 to 30 ( 25 channels)

Downstream = Channel 31 to 255 (255 channels)

DMT FREQUENCY SPECTRUM

DSLAMDigital Subscriber line Access Multiplexer

DefinitionDefinition A DSLAM is a Network Device, usually placed at a

Telephone Company Central Office, That Receives

Signals from multiple customer of DSL Connections

and puts the signals on a high-speed backbone line

using Multiplexing Techniques.

DSLAM enables a phone company to offer business

or home users the fastest Phone Line Technology

(DSL) with the fastest backbone Network

Technology.

THANK YOU