Ppt1

Introduction to Ericsson

Basics of

Telecommunication:

ATM,ADSL,TDM,PSTN,SDH

Presented By: Sandeep Kumar

Ericsson: Introduction• Founded by L. M. Ericsson on 1st April, 1876 as a small telegraph

repair shop at Stockholm(Sweden)

• President & CEO : Mr. Hans Vestberg

• Chairman : Mr. L. Johansson

• Headquarters : kista, Stockholm, Sweden

• Currently Ericsson is divided into 10 regions and one head office

• RINA

Ericsson : Operations• Each region has a region head under which many CU’s are there.

• Mr. Steven Moodie (Active region head of RINA)

• Operation are divided into four sections:

(i) Projects

(ii) EP

(iii) CS : Customer Service Manager

(iv) MS

Basic Telecommunication

Telecommunication

Wire line

Basic Telephony (Landline

Phones )

Ethernet ATMAnd many

more

Wireless

ATM• Stands for “Asynchronous Transfer Mode”

• Designed in early 1990’s

• Connection-oriented service : Virtual Circuits

• Fixed size packets: Cells (53 Bytes : 5 Bytes for Header and 48 Bytes for Payload(User Data))

• Guaranteed to deliver packets in order

• ATM Reference Model

ATM Reference Model• Three layers:

(i) Physical layer

(ii) ATM layer

(iii) AAL layer

• Three-dimensional Model• User Plane

• Control Plane

• Layer & Plane management

ATM Reference Model

(Cont’d)

ADSL• Stands for “Asymmetrical Digital Subscriber Line”

• Different speeds for Downstream and Upstream.

• A technology that is used to provide faster data transmission over copper telephone lines in comparison to a traditional modem can.

• Utilizes entire capacity of local loop :uses frequencies that are not used by voice telephone call

• Uses FDM

• ADSL Radius

ADSL Operation

TDM : Time Division

Multiplexing Time Divison Multiplexing

• Two different Schems:

• Synchronous TDM

• Statistical TDM

Time is divided into slots

simultaneous transmission of multiple signals across a single data link

Synchronous TDM

• Each input has a reserved time slot in output frame whether it has data to send or not i.e. no. of time slots in a frame = no. of input lines

• Synchronization bits (framing bits) are added to each frame : provides synchronization between multiplexer and demultiplexer

• Data rate management

• multilevel multiplexing

• multiple-slot allocation

• pulse stuffing

Synchronous TDM (Cont’d)

Multilevel multiplexing Multiple-slot allocation

Pulse stuffing Framing bits

Statistical TDM

• Slots are dynamically allocated to improve bandwidth efficiency

• The multiplexer checks each input line in round robin fashion; it allocates a slot for an input line if the line has data to send; otherwise, it skips the line and checks the next line.

• No synchronization bits are required

• Each output slot carries data as well as the destination address.

TDM slot comparison

PSTN• Stands for “Public Switched Telephone network”

• Deals with basic telephony

• Structure of telephone System

• Initially, a separate wire is used between two telephones to communicate

• Bell’s Switching Office

(a) Fully-interconnected network(b) Centralized switch.(c) Two-level hierarchy.

PSTN (Cont’d)• Finally, in 1984 a new Structure of Telephone System is given

• Three Major Components:

• Local loops

• Trunks

• Switching offices: End Office, Toll Office and Intermediate Switching Office

SDH• Stands for “Synchronous Digital Hierarchy”

• Synchronous : One master clock & all elements synchronize with it

• Digital : Information in binary

• Hierarchy : set of bit rates in a hierarchical order

• Designed by ITU to provide a Standard optical transmission System which uses Synchronous TDM

• SDH defines a hierarchy of standardized digital data rates called STM (Synchronous Transport Module)

SDH (Cont’d)• STM uses the following Synchronous Transport Modules :

SDH Signal Bit Rate (Mbps)

STM-1 155

STM-4 622

STM-16 2488

STM-64 9953