Difference between revisions of "Telecommunication Case Study"

Latest revision as of 18:51, 26 May 2011

Description

The case study described below is about mobile phone services portability. Voice and data services are provided by a set of mobile telecommunication companies around Europe. There companies are usually called Cell Phone Operators (CPOs). Some of these CPOs operate in a single country, whereas some others are big CPOs that have branches in several countries. Inhouse services are offered by the CPO to manage all the customers and the stipulated contracts. Moreover the customers can view personal information about their contracts accessing to a suitable services made available by the telephone operator, or some user could query all the services offered by the CPO accessing its public services. Not all the CPOs have their own telecom infrastructures; some of them rent the network services from big telecom companies and provide a service to the users. Such operator are called Virtual Operators (VOs). The case study presented in this chapter is about the additional services that a company support to allow the portability of the phone number and the portability of services. The possibility to change a mobile phone operator without changing the mobile phone number is one of the mandatory services that a mobile phone operator must provide. National and European laws regulate this procedure with the aim of allowing the customers to freely select the best company according to their requirements to be advantaged by the more suitable or cheapest services offered by the new phone operator, without advising his contacts of a new telephone number. It might also happen that the portability is only about the services on which a customer is subscribed. For instance, a customer might move from an European Country to another for a limited period, e.g., one year, but keeping his subscription, even with a new phone number, with the company and using the same services already available but not by roaming. At the end of such period, the customer could move back to his home country again, picking up his original telephone number and subscription. Starting from this description of the case study, we could identify the following stakeholders:

• Cell Phone Operators (CPOs)
• Customers

Business Goals and Domain Assumptions

Business Goals and the Domain Assumptions define the functionalities and the properties of both the machines and the environment where the systems operate. Whereas the business goals state the functionalities of the product, the domain assumptions report properties or restrictions of the system.

Business Goals

Domain Assumptions

Domain Analysis

Strategic Dependency Model and Context Diagram

The figure below illustrates the strategic dependency diagram of the case study. The diagram puts in evidence the business goals (the ellipses in the diagram) shared among the actors (the yellow circles in the diagram) of the scenario, showing the dependencies among them. The CPOs offer their services satisfying the national and the european rules; their goal is the provisioning of services useful to the customers in order to get information about the status of their contracts and/or to change them. In particular the current case study focuses on the provisioning of the telephone number portability service; such service should be offered to the customer in a transparent way.

Figure below illustrates the context diagram of the current case study. In the context diagram, all the actors that appear in the business goals and scenarios are agents.

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Domain Model

Figure below illustrates the domain model of the current case study. A UML notation is used to represent the entities and the actors involved in the case study and the relationships among them. The CPO stipulates a Contract with a Customer. A contract is characterized by the particular Fares to pay for the service usage; it could include the basic Voice Service or some additional service (Value Added Service) provided by the CPO, such as e-mail services, SMS services and so on. When a Customer requires a Telephone Number Portability of his telephone number moving from a CPO to another one, such portability is associated to a contract. Moreover, the diagram illustrates the possibility of a Customer to access to different type of Services provided by the CPO.

And I thought I was the sensible one. Thanks for setting me staright.