software engineering project on global system for mobile communication

8/7/2019 Software engineering project on GLOBAL SYSTEM FOR MOBILE COMMUNICATION

1/22

PROBLEM STATEMENT

We have to make software which can perform all the basic functions that should be th The purpose of this software is to simulate a GSM (Global System For Mobile) mobilesystem.. ere in a mobile phone. Some of these functions are

1) Making Calls2) Receiving Calls3) Sending Messages4) Receiving Messages5) Maintain SIM Information6) Roaming Management

The mobile phone should be capable of accessing the base tower center wirelessly andinteract with it according to the function performed as and when required. It should beable to handle two different frequencies at the same time as when we would be making or receiving calls we would need different frequencies to send and receive data. The mobile

phone should have its information numbers i.e. the set of characteristics that woulddistinguish it on the network. These characteristics could be

IMEI number IMSI number model number Phone number

EMI number

These characteristics would have to be send to the main service center where all thisinformation will be stored in the databases whenever the SIM card is activated. Themobile will be searched by its phone number whenever there is a call made to it. Allthe BTS (Base Tower Center) will be sent the phone number and then it will be foundin whose access area is that phone located and hence a call will be made active

between the two cell phones.


2/22

SOFTWARE REQUIREMENTSSPECIFICATION

(SRS)

1. INTRODUCTION


3/22

This document aims at defining the overall specifications for GLOBAL SYSTEMFOR MOBILE COMMUNICATION. Efforts have been made to define therequirements exhaustively and accurately. The final product will be having onlyfeatures/ functionalities mentioned in this document and assumptions for anyadditional functionality should not be made by any parties involved in the developing

of this product.

1.1 PurposeThe purpose of this Software Requirements Specification is to describe our proposedsoftware system called GSM-TECH. GSM-TECH is to provide a means by which auser can communicate with other user through SMSes and Calls and to maintain the SIMinformation and manage the above specified functions while roaming.

1.2 ScopeThis new technology will provide advanced solutions for communication among users. Itwill allow the users to communicate through GSM Technology quickly and easily. Thewhole GSM system consists of a Mobile Station, a Base Station System, a Network Station Subsystem, a Short Message Service Internetworking Mobile Switching Center, aShort Message Service Center and a Short Message Service Gateway Message SwitchingCenter. The Mobile Station consists of a Mobile Equipment and a SIM Card. The BaseStation Subsystem consists of a Base transceiver Station and a Base Station Controller.The Network and Switching Subsystem consists of a Mobile Switching Center, Visitor Location Register, a Home Location Register and an Authentication Center.

1.3REFRENCESWikipedia

1.4 Definitions, Acronyms and Abbreviations

Global System For Mobile Communication (GSM) - It is digital wirelessnetwork standard that provides a common set of compatible services capabilitiesto common users.

Mobile Station MS

Mobile Equipment - ME

SIM (Subscriber Identity Module) is a smart card that is inserted in a ME.

Base Station System The BSS connects the MS and the NSS


4/22

Base transceiver Station The BTS consists of transmitter, receiver and thesignaling equipment to contact the MSs via Radio Interface.

Base Station Controller The BSC is responsible for the switching functions in

the BSS and is in turn connected to the MSC in NSS

Network and Switching Subsystem The NSS supports the switching functions,subscriber profiles and mobility management.

Mobile Switching Center The MSC perform the basic switching function inthe NSS. The MSC communicates with other networks also using the signaling

protocols.

Gateway MSC - GMSC

Home Location Register The HLR is the location register to which an MSidentity is assigned for record purposes such as directory number, profileinformation, current location and validation period.

Visitor Location Register The VLR is the location register that stores thetemporary record for the mobile user, when the mobile user visits other networks

Authentication Center The AuC is used in the security data management for the authentication of subscribers.

User Interface - The part of the system that all users interact with. The User Interface both receives input from and displays results to the user. The user interface is the Mobile equipment.

Personal Communications Services The PCS refers to a wide variety of wireless access and personal mobility services provided through a small terminal,with the goal of enabling communications at any time.

Public Switched Telephone Network The PSTN connects many PCSes to provide access to wireless telephones.

Short Message Service Internetworking MSC SMS IWMSC

Short Message Service Center The SMS is first delivered to the SM-SC.

SMS GMSC - The SM-SC is connected to the GSM network through a specificGSM MSC called the Short Message Service Gateway MSC. The SMS GMSClocates the current MSC of the message receiver and forwards the message to thatMSC.


5/22

PIN Pin Identification Number

PUK PIN Unblocking Key

n/w - network

1.5 Overview

This document is organized into major sections that will include our developmentapproach, time scheduling and project schedule as well as more technical specifications.To get a better idea of how the software will operate the technical aspect of the documentwill detail the uses for the system into use cases and a small explanation for each.

2 OVERALL DESCRIPTIONSThe proposed GSM-TECH system satisfies all standards that we have established for our

products. It will be functional, secure, and easy to use.

2.1 Product perspective

The application will be a system in which the user will interact with the GSM network through a small display in the ME.

2.1.1 System InterfaceBSS

2.1.2 User Interface

The application will have a user-friendly and menu based interface.

2.1.3 Hardware Interface

The hardware interface is a ME that may or may not be connected to the US basedkeyboard and should have buttons marked from 0-9.

2.1.4 Software Interfaces

The ME is Java based system and a menu based equipment.


6/22

A decoder to decode the message.An encoder to encode the message.

2.1.5 Communication Interfaces

Radio InterfaceA-InterfaceSIMBTSBSCMSCAuC

2.1.6 Memory Constraints

For ME: As specified by the developer (specified: 500 KB)For Network Operator: Depending on the Number of subscriber (specified: 500 GB)

2.1.7 Operations

This product release will have a back-up database that will be handled directly by thenetwork operator that will contain the information of the subscriber.

2.1.8 Site Adaptation Requirements

The terminals at the other user sites will have to support the hardware and softwareinterfaces in above sections.

2.2 Product functions

The requested product will allow: Making Calls. The user can make calls to any person who is connected to the

GSM network. Receiving Calls. The user can receive calls from any person who is connected to

the GSM network. Sending Messages. The user can send messages to anyone who is connected to the

GSM network. Receiving Messages. The user can receive messages from any person who is

connected to the GSM network.


7/22

Maintain SIM Information. The SIM contains information such as PIN number,PUK number, Customized Calling Numbers, the Messages received and thenames of the preferred networks.

Roaming Management. The Message Switching Center maintains the location of the Mobile Equipment on its own.

All the users have to first enter the PIN number on the mobile display screen the firsttime the user Enter the SIM card, in order to activate the SIM Card login before using theGSM system. All users will have a password-secured access to the network. Each user can change the PIN number through his ME.If for the first three time the user enters the wrong PIN then he/she has to enter the PUK number in hi ME. This PUK number is provided to the user by the network operator.

2.3 User Characteristics

GSM-TECH will have an easy to use menu-driven interface. Even users without anyexperience will be able to learn how to operate the system in no time.

2.4 Constraints

The ME will not be able to handle large amount of data.

2.6 Apportioning Of Requirements

In the near future there will be call charges as per the network operator specifications.Also some added functionalities are bound to come.

3 SPECIFIC REQUIREMENTS

In this section all the requirements are specified in detail to make the SRS complete.

3.1 External Interface

3.1.1 User Details

The user is an actor who acts at the MS to interact with the system.The user is provided by a 10-digit mobile number by the network operator to identify theuser. The users details purposes such as directory number profile information current


8/22

location and validation period are stored in the HLR that is used during the verificationand to know the current location of the user. The user related data also include a list of information such as Customized Calling Numbers, the Messages received and the namesof the preferred networks.

3.1.2 Hardware Interface

As stated in 2.1.3

3.1.3 Software Interfaces

As stated in 2.1.4

3.1.4 Communication Interfaces

As stated in 2.1.5

3.2 Functions

3.2.1 To Maintain SIM Information

The SIM is protected by a Personal Identification Number (PIN) between four to eightdigits in length. The PIN is initially loaded by the network operator at the subscriptiontime. This PIN can be changed or deactivated by the user. All the users have to first enter the PIN number on the mobile display screen the first time the user Enter the SIM card, inorder to activate the SIM Card login before using the GSM system. All users will have a

password-secured access to the network. Each user can change the PIN number throughhis ME.If for the first three times the user enters the wrong PIN then he/she has to enter the PUK number in hi ME. This PUK number is provided to the user by the network operator.A SIM contains the subscriber-related information, including PIN and PUK Codes. Thesubscriber related data also include a list of information such as Customized Calling

Numbers, the Messages received and the names of the preferred networks.

3.2.2 Making and Receiving Calls

Registration process


9/22

Before a user makes a call the ME must be registered by the VLR of the visited location.The HLR must also be informed about this registration. To access the MS, the HLR isqueried to find the current VLR of the MS.This registration process is given as-:

The MS periodically listens to the broadcast frequency from the BTS. If the MS

detects that it has entered a new the mobile phone network location area, it sends aregistration message to the new VLR using the Standalone Dedicated ControlChannel that is used for signal processing and for short messages.

The new VLR communicates with the old VLR to find the HLR of the MS. Thenew VLR then performs the authentication process.

After the process is authenticated, the new VLR send the registration messages tothe HLR. If the registration request is accepted the HLR provides the new VLR with all relevant subscriber information for call handling.

The new VLR informs the MS of the successful registration. After the new VLR is registered, the HLR sends a deregistration message to the

old VLR. The old VLR cancels the record for the MS and sends an

acknowledgement to the HLR for the cancellation.

Make CallsThe process of making calls (outgoing calls) is given as-:

The user dials the telephone number , presses the send or talk key. The mobile phone sends a call setup request message to the visited MSC. This

is done via BTS and the BSC. The BSC is connected to the MSC through theA Interface.

The MSC is switch that queires the HLR to find the current VLR of the MS.The HLR queries the VLR in which the MS resides to get a a temporarynumber from the VLR routable address.

The VLR returns the routable address to the orignating switch that is the MSCthrough the HLR.

This number is relayed to the Gateway MSC, which uses it to route the call toanother Mobile Switching Center, called the Visiting MSC.

Based on the routable address, a voice circuit is set up from the orignatingswitch to the MS through the visited MSC.

Receive CallsThe proceess of receiving calls (incoming calls) is given as-:

When someone places a call to a mobile phone , they dial the telephonenumber associated with the phone user and the call is routed to the mobile

phone operator 's Gateway Mobile Switching Centre. The Gateway MSC ,as the name suggests, acts as the "entrance" from the Public SwitchedTelephone Network to the provider's network.
http://en.wikipedia.org/wiki/Network_Switching_Subsystemhttp://en.wikipedia.org/wiki/Telephone_numberhttp://en.wikipedia.org/wiki/Telephone_numberhttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Telephone_numberhttp://en.wikipedia.org/wiki/Telephone_numberhttp://en.wikipedia.org/wiki/Telephone_numberhttp://en.wikipedia.org/wiki/Mobile_phone_operatorhttp://en.wikipedia.org/wiki/Mobile_phone_operatorhttp://en.wikipedia.org/wiki/Mobile_phone_operatorhttp://en.wikipedia.org/wiki/GMSChttp://en.wikipedia.org/wiki/Public_Switched_Telephone_Networkhttp://en.wikipedia.org/wiki/Public_Switched_Telephone_Networkhttp://en.wikipedia.org/wiki/Telephone_numberhttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Mobile_phonehttp://en.wikipedia.org/wiki/Telephone_numberhttp://en.wikipedia.org/wiki/Telephone_numberhttp://en.wikipedia.org/wiki/Mobile_phone_operatorhttp://en.wikipedia.org/wiki/Mobile_phone_operatorhttp://en.wikipedia.org/wiki/GMSChttp://en.wikipedia.org/wiki/Public_Switched_Telephone_Networkhttp://en.wikipedia.org/wiki/Public_Switched_Telephone_Networkhttp://en.wikipedia.org/wiki/Network_Switching_Subsystem


10/22

The HLR then queries the VLR and requests a temporary number from theVLR.

When the call is received by the Visiting MSC, the temporary number isused to find the phone's record in the Visited Location Register. Thisrecord identifies the phone's location area and the exact location of the

mobile is returned to the Visited MSC. The VMSC then forwards the call to the appropriate phone, and the phone

rings. The subscriber then answers the call and a speech path is created through

the Visiting MSC and Gateway MSC back to the network of the personmaking the call, and a normal telephone call follows.

3.2.3 Send and Receive SMS

Sending and receiving messages occur simultaneously.The steps in sending and receiving a message are as follows-:

The originating MS that sends the SMS is first transferred to the SMS-IWMSC. From there the message is delivered to SM-SC. The SM-SC is connected to the SMS GMSC

The SMS GMSC finds the current location of the MSC of the message receiver and forwards the message to the MSC.

The MSC then broadcasts the message to the BSS and the BTS page thedestination MS.

The destination MS contains a special software to decode the message and tostore the message at the MS.

3.2.4 Roaming Management

When the mobile user visits other network other than the home system, the user isassociated with the VLR of the visited system where a temporary record for the mobileuser is created. The mobile user is registered at the new VLR.The registration process is described in the following steps-:

When the mobile user moves from one visited system to another, it must register in the VLR in the new visited system.

The new VLR informs the mobile users HLR of the persons current location-the address of the new VLR. The HLR sends an acknowledgement, whichincludes the MSs profile, to the new VLR.

The new VLR informs the MS of the successful registration.
http://en.wikipedia.org/wiki/Location_areahttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Location_areahttp://en.wikipedia.org/wiki/Telephone


11/22

After the new VLR is registered, the HLR sends a deregistration message to theold VLR. The old VLR cancels the record for the MS and sends anacknowledgement to the HLR for the cancellation.

3.5 Software System Attributes

3.5.1 Security

Security will be achieved by ensuring that each user's enter the PIN correctly.If for the first three times the PIN number is not entered correctly the SIM is blockedautomatically. To unblock the SIM the user has to enter the PUK number that is provided

by the network operator.

3.5.2 Maintainability

The application will be designed in a maintainable manner.

3.5.3 PortabilityThe application will be easily portable on any Windows based system has the MS-Officeinstalled.

3.5.4 Reliability

The system will be very much reliable

3.5.5 Availability

As per the Rules and Regulations of the government.

3.6 DATABASE

3.6.1 HLR The HLR is database used for mobile user information management.The HLR consists of three type of information:

Mobile Station Information such as the phone number. Location Information such as the address of the VLR where the MS resides. Service Information such as the service subscription, service restriction and

supplementary services.

3.6.2 VLR


12/22

The VLR is the database of the service area visited by an MS. The VLR containsall subscriber data of an MS required for call handling and other purposes. Similar to the HLR, the VLR information consists of three parts:

Mobile Station Information such as the phone number. Location Information such as the MSC number and the location area ID. Service Information which is the subset of the service information stored

in the HLR?

4 Document ApprovalAs per stated by the government.

5 Supporting InformationGSM-TECH has examined the needs of GSM and has produced an efficient plan tocreate a comprehensive system to handle calls and messages. Due to our experience withsoftware development, we are confident that this system will meet our high qualitystandards of being user friendly, secure, and reliable. Our management plan forecasts thatwe will have time to facilitate plenty of customer feedback during development, anddeliver a satisfactory finished product to GSM operators on or before the scheduled date.


13/22

USE-CASE DIAGRAM

Reg i s t e r S IM

A c t i va t e S IM

R o a m i n g M a n a g e m e n t

M a k e a n d R e c e i ve C a l l s

M o b i le s t a t io n

S e n d a n d R e c e i ve S M S

< < e x t e n d > >


14/22

DATA FLOW DIAGRAM

MAKECALLS

GSMSYSTEM

RECEIVE CALLS

SENDSMS

RECEIVE SMS

ACTIVATESIM

GSMSYSTEM

LEVEL - 0


15/22

HLR

VLR

MOBILESTATION

I

ActivateSIM

MakeCalls

MSC

FindLocationof MS II

Received at MS

II

Calldiverte

d toMS II

MOBILESTATION

II

DFD LEVEL IMAKING AND RECEIVING OFCALLS


16/22

HLR

VLR

MOBILESTATION

I

ActivateSIM

SendSMS

MSC

Find

Locationof MS II

Received at MS

II

SMSdirecte

d toMS II

MOBILESTATION

II

DFD LEVEL I SENDING AND RECEIVING OF SMS


17/22

INTERACTION DIAGRAM (ACTIVATE SIM)

: Mobile stationSIM PUK MSC

Enter PIN Code

Verify PIN Code

Incorrect

Enter PUK Code

Verify PUK Code

correct, then activate SIM

Activated

Block the ME and ask for the PUK Code

Request for PUK Code

After verification of user provide PUK Code to user

not correct, keep blocking the SIM


18/22

INTERACTION DIAGRAM (REGISTER SIM)

: Mobile station New VLR Old VLR HLR

Periodically check for Broadcast Frequency

new frequency detected, send request of Registration to the new VLR

Asks old VLR for the location of HLR

Perform Authentication Process

Registration accepted by HLR

Provides with all relevant subscriber information for call handling

Informs of successful registration process

Send deregistration message


19/22

INTERACTION DIAGRAM(MAKE AND RECEIVE CALLS)

: Mobile stationMSC HLR VLR Visiting MSC

Call routed to MS C

Dial number

Queries the HLR about the location of VLR

Quiries VLR to get a a temporary number from the VLR routable address

Returns the routable address

Number Relayed to visiting MSC

Find the current location of destination VLR

Call directed to the destination MS


20/22

INTERACTION DIAGRAM(SEND AND RECEIVE SMS)

: Mobile stationSMS-IWMSC SM-SC SMS-GMSC MSC

Send SMS

Mssage is forwrded

Message reforwaded

Get the current location of the MSC of the receiver

Receive the current location of the MSC of the receiver

Broadcast the message to the Destination MS via BSC and BTS

Decode the received message


21/22

INTERACTION DIAGRAM(ROAMING MANAGEMENT)

: Mobile station New VLR Old VLR HLR

user moves to new area, send request of Registration to the new VLR

Informs of successful registration process

Asks old VLR for the location of HLR

Perform Authentication Process

Registration accepted by HLR

Provides with all relevant subscriber information for call handling

Send deregistration message

Cancels all previous User's record


22/22

ACTIVITY DIAGRAM

Authentication

Register Sim

Make Call SendMessage

New VLR sendsregistration request to HLR

Call divertedto MSC

DestinationMSC found

Visited MSCdivert call to MS

Message directed to SM-SCvia SMS-IWMSC

HLR register new VLR

Message forwarded toSMS-GMSC

Message forwarded todestination MSC

Destination

HLR registersnew VLR

New VLR confirms theMS of registration

software engineering project on global system for mobile communication

Documents