Architecture-centric approach to wireless service engineering

Telecom carriers, wireless application service providers and traditional Internet service providers are developing new services and new business models to support the mobile customer and create new revenue opportunities. At the same time, technologies are evolving faster and faster, and provide always-new features that make software engineering both promising and challenging for this domain. Next Generation Networks (NGNs) and services, GRID services and mobile services over 3G/4G technologies, such as I-mode and UMTS, represent some examples. In this evolving scenario, industry requires software engineering techniques that help in mastering time-to-market service engineering, fast and profitable evolution, know-how protection and exploitation. In order to respond to the needs of various stakeholders related to service architectures, architecture descriptions have to contain several viewpoints, at different levels of abstraction, defined by the QADA (Quality-driven Architecture Design and quality Analysis) method. To achieve this multi-perspective representation, differing modeling notations for both abstract and concrete architecture descriptions are needed. That is to prevent confusion caused by diverse meanings for the same symbol. In particular, this paper proposes a service engineering approach for architecting wireless services. The approach relies on a modeling notation extending OMG UML, and it is based on two separate levels of abstraction: (1) High-level notation should enable drafting and understanding the whole of a system. It means that conceptual models should be easy to modify and should not contain too specific details. It should also provide a suitable communication mean among stakeholders that need to interact on a technical basis, but also consider business issues. (2) Low-level notation should support detailed design. It means that concrete models should integrate the neglected or informally described details of high-level models. It should also support design-level reuse, by providing both context-independent and context-dependent models. In order to facilitate understanding, service engineering requires readable, simple and intuitive notations for both the conceptual and concrete architecture descriptions. High-level notation at the conceptual level should allow the grouping of functionality to services according to commonalties and variabilities and assist in the creation of interdependencies between the services. It also provides the means to draft service and work allocation for a distributed system in a distributed development environment. On the other hand, the notation at the concrete level should allow the separation of the externally and internally visible structure and behavior. In addition, distributed interfaces, local interfaces and interactions among components and with external products should be clearly identified. The latter needs special attention, as interactions typically take place among different business entities, using different protocols, standards and business policies.