PREPARED BY-ISHA

11UEC045

INTRODUCTION TO COMPANY

WHAT IS GSM?

CDMA

PRI AND D CHANNEL

E1 CONCEPT

SIGNAL TRACE

ADD HUNDERED GROUP

CALL DATA RECORD BACKUPS

Founded by Jamsetji Tata in 1868, the Tata group is a global enterprise, headquartered in India. It comprises over 100 operating companies in seven business sectors: communications and information technology, engineering, materials, services, energy, consumer products and chemicals.

Tata companies have operations in more than 100 countries across six continents, and export products and services to over 150 countries. The total revenue of Tata companies, taken together, was $96.79 billion (around Rs527,047 crore) in 2012-13, with 62.7 percent of this coming from business outside India.

Global system for mobile communication

(GSM) is a globally accepted standard for

digital cellular communication.

GSM is the name of a standardization group

established in 1982 to create a common

European mobile telephone standard that

would formulate specifications for a pan -

European mobile cellular radio system

operating at 900 MHz.

Year Mobile System

1981 Nordic Mobile Telephone (NMT)

450

1983 American Mobile Phone System

(AMPS)

1985 Total Access Communication

System (TACS)

1986 Nordic Mobile Telephony (NMT)

900

1991 American Digital Cellular (ADC)

1991 Global System for Mobile

Communication (GSM)

1992 Digital Cellular System (DCS)

1800

1994 Personal Digital Cellular (PDC)

1995 PCS 1900—Canada

UPLINK 890-915MHZ

DOWNLINK 935-960MHZ

DUPLEX DISTANCE 45MHZ

CARRIER SEPARATION 200KHZ

NUMBER OF CHANNELS 25MHZ/200KHZ=124

CHANNELS DEFINED IN SWITCH 124

ACCCESS METHOD TDMA

The switching system (SS) is responsible for

performing call processing and subscriber-

related functions. The switching system

includes the following functional units:

home location register (HLR)

mobile services switching center (MSC)

visitor location register (VLR)

authentication center (AUC)

equipment identity register (EIR)

The HLR is a database used for storage and

management of subscriptions. The HLR is

considered the most important database, as it

stores permanent data about subscribers,

including a subscriber's service profile, location

information, and activity status. When an

individual buys a subscription from one of the

PCS operators, he or she is registered in

the HLR of that operator.

The MSC performs the telephony switching

functions of the system. It controls calls to and

from other telephone and data systems. It also

performs such functions as toll ticketing,

network interfacing, common channel signaling

, and others.

The VLR is a database thatcontains temporary

information about subscribers that is needed by

the MSC in order to service visiting subscribers.

The VLR is always integrated with the MSC. When a

mobile station roams into a new MSC area, the VLR

connected to that MSC will request data about the

mobile station from the HLR. Later, if the mobile

station makes a call, the VLR will have the

information needed for call setup without having

to interrogate the HLR each time.

—A unit called the AUC provides authentication

and encryption parameters that verify the

user's identity and ensure the confidentiality of

each call. The AUC protects network

operators from different types of fraud found

in today's cellular world.

The EIR is a database that contains information

about the identity of mobile equipment that

prevents calls from stolen, unauthorized, or

defective mobile stations.

The AUC and EIR are implemented as stand-

alone nodes or as a combined AUC/EIR node.

Code Division Multiple Access (CDMA) is a digital technique for sharing the frequency spectrum. Multiple users are assigned radio resources using spread Spectrum techniques.

Although all users are transmitting in the same RF band, individual users are separated from each other via the use of orthogonal codes. CDMA is based on proven “Spread Spectrum communications technology”

There are several CDMA implementations that are currently deployed or under development. The first commercial and most widely deployed CDMA implementation is cdmaOne.

CDMA is an advance digital technology that can offer 7 to 10 times the capacity of analog technologies and up to 6 times the capacity of digital technologies such as TDMA. The speech quality provided by the CDMA systems is far superior to any other digital technology particularly in difficult radio environments such as dense urban areas and mountainous regions.

It provides the most cost effective solution for cellular operators. CDMA Technology is constantly evolving to offer customers new advanced services. The mobile data speeds offered through CDMA phones are increasing and new voice codecs provide speech quality close to wire line. Internet access is now available through CDMA terminals.

The CDMA systems and technology have been standardized under Interim standard-95 (IS-95 A&B).

MOBILE STATIONS ISDN NUMBER (MSISDN)

=> Is the mobile number used in a GSM PLMN (Public Land

Mobile Network)

MSISDN = Country Code + National Destination Code +

Subscriber number

e.g. 63 + 0918 + 8889999

Maximum length is 15 digits.

INTERNATIONAL MOBILE SUBSCRIBER IDENTITY (IMSI)

=> Is the subscriber number used over radio path for all

signaling in the GSM PLMN.

This number is stored in SIM (Subscriber Identity Module), HLR

(Home Location Register,

and VLR (Visitor Location Register).

IMSI = MCC + MNC + MSIN

= Mobile Country Code + Mobile Network Code + Mobile

Identification Number

[ 3 digit ] [ 2 digit ]

[ 11 digit ]

e.g. 502 + 19 + 2345451

TEMPORARY MOBILE SUBSCRIBER IDENTITY (TMSI)

=> Is used for the subscriber's confidentiality. Since the TMSI has only

local significance

(within MSC/VLR) the structure of the TMSI can be chosen by the

Vendor.

But the size must be 1/2 of the size of IMSI. Each time a mobile

request for location

updating or call setup, MSC/VLR allocates to the IMSI a new TMSI, so

the TMSI

is used on the signaling path, protecting the IMSI identity. Plus since

the TMSI is half

the size of IMSI, we can page twice the amount compared to IMSI.

SIM is used to provide storage on subscriber related information as following :

• IMSI (International Mobile Subscriber Identity).

• Temporary network data like TMSI, LAI, Location update status.

• Subscriber Authentication Key (Ki) and Ciphering Key (Kc) which are used for security purposes.

• BCCH information : List of carrier frequencies to be used for cell selection.

• Forbidden PLMN.

• Language preference.

• PIN number (Personal Identification Number) and PIN error counter.

• PUK number (Personal Unlock Key) and PUK error counter.

The Primary Rate Interface (PRI) is a standardized telecommunication service level within the Integrated services digital network (ISDN) specification for carrying multiple DS0 voice and data transmissions between a network and a user.

D channel (delta channel) is a telecommunication term which refers to the ISDN channel in which the control and signalling information is carried.

The bit rate of the D channel of a basic rate interface is 16 kbit/s, whereas it amounts to 64 kbit/s on a primary rate interface.

The E carrier system has been created by the

European Conference of Postal and

Telecommunications Administrations (CEPT) as a

digital telecommunications carrier scheme for

carrying multiple links.

The E-carrier system enables the transmission of

several (multiplexed) voice/data channels

simultaneously on the same transmission facility.

The E1 standard defines the physical

characteristics of a transmission path, and as

such it corresponds to the physical layer (layer

1) in the OSI model.

E1 is any medium that is capable for enabling

32 persons to make calls at a time.

There are 32 timeslots in an E1.

The timeslots are numbered from 0 to 31.

Each time slot has a rate of 64 kbit/s.

Total bit rate is 2.048 Mbits/s(ie:32*64=2048)

0th slot is used for Synchronization b/w A party & Bparty.

16th slot is for signaling (ie to establish call b/w A party & B party).

PHYSICAL CONCEPT

Basically there are 2 E1’s:

Electrical E1 &

Optical E1.

Physically an electrical E1 is any twisted pair

of cable having a Transmitter & a Receiver .

Optical E1’s are defined in terms of STM’s

(Synchronous Transport Module)

1 STM = 63 E1’s. It is basically an optical

fiber connectivity. In STM E1’s are identified

with the help of KLM’s & port numbers.

Total bit rate in 1 STM = 63*2.048= 155.52

Mbit/s.

0 1 2 ….. … 15 16 ….. 29 30 31

Synchr

onizati

on

Signalli

ng

:E1 channel Distribution

Click on Database Interface Service

Manager User Configuration THEN

Local Office User Configuration (O)

Fill the number & click on Query.

Check the Call Right Template Number

Click on other prop. Tab to check call barring etc.

To Modify any property

Click on modify and do the required changes.

Now to check DChannel Status. Go To Service Manager User Conf. ISDN User Type Relative Configuration(R) ISDN User Config.(P)

FIG 11.12: PRI STATUS

Here fill the number as shown & click on query. Note down the D Channel

Now go to MML Wizard type 5600 & select 5600 (Display Information)

Fill Module Number 3 or 4 , Minimum D channel ID – (one less then the required Dchanneli.e. 102) , Maximum DChannel ID – (one more then the required Dchannel i.e. 102). Click on Run.

Check the Status of Required DChannel

i.e. 102. here its OOS (Out of Service)

Click on signal trace option.

Click on the type of trace you want to do.

Here Q 931 Trace Is being performed. It can

be done By Module Number, By Node, Or By

SDN Numbers as shown. Then Click Next.

CALL TRACE

Centrex is a PBX-like service providing switching at the central office instead of at the customer's premises. Typically, the telephone company owns and manages all the communications equipment and software necessary to implement the Centrex service and then sells various services to the customer.

No switching equipment resides on the customer's premises, as the service is supplied and managed directly from the phone company's exchange site

With a PBX, stations inside the group can call each other with 3, 4 or 5 digits, depending on how large the group, instead of an entire telephone number (unit number).

Go to Service Manager User Config.

Local Office Code and DNHM

Configuration

Select the desired area code and office code

where the hundred group is

To be added. Click Add

Fill the zone & das number (same as in other)

and add the hundred group.

Example: 02 added here. The hundred group

(02) is added.

It is important to take backups from time to time because in case of a sudden system failure all the data can be lost. So to ensure secure and data records backups are taken twice a week.

TYPES OF BACKUPSCDR

CP

APG

LOGFILE

The call detail record (CDR) feature creates text records of call related data. The data recorded includes calling and called numbers, call origination/connect time, the time the call was disconnected, the disconnect reason, the DLCI field to identify the originating PRI, and the bearer (B) channel used.

There are CDRs for normal calls, i.e., calls that were successfully completed and for failed calls.

All call-related operation failures will also be recorded in a CDR.

A call data record (CDR) is kept for billing Yield historical account of cell phone’s Locations.

Pc Anywhere

A system is presented for logging and recording a call to a call network. The system comprises a voice print logic for generating a voice print of a caller who is making a call to a call network.

A telecom routing switch generates a correlated telecom router switch log file by appending the voice print of the caller to a telecom router switch log file for the call.

The voice print is utilized to retrieve and to consolidate the correlated telecom router switch log file, the correlated telecom software system log file, and the correlated contact center agent log file into a single correlated file for the call.

Fig.11.22:Log file generation

MGW(Media Gateway)

The maintenance terminal is used to interact

with the system software for configuration

changes and maintenance purposes. This is

achieved using a range of MMI (man/machine

interface) and SMI (System Maintenance

Interface) commands.

Proprietary unified packet gateway.

Can function as a gateway

Uses:

Hot swapping and redundancy backup, double power supplies, and overvoltage and overcurrent protection for key boards

Overload control, flow control, resource check, self fault detection, system software backup, and configure consistency check for stable and reliable system operation

CDR cache function for charging reliability

Hot patch technique for software operation reliability

Route backup and route load-sharing modes for preventing single-point failures and ensuring high network reliability