Service-Oriented Middleware: Overview and Illustrative Example

In this chapter we present an emerging approach to develop systems for WSN, named Service-Oriented Middleware (SOM), in which the WSN is logically viewed as a service provider for consumer applications. SOM provides abstractions for the complex underlying WSN through a set of generic and/or application-specific services. Services as data aggregation, adaptation, security, self-organization, resource management as well as other advanced services can be designed, implemented, and integrated in an SOM framework to provide a flexible and easy environment to develop effective WSN applications. Moreover, the intrinsically decoupled nature of the various components involved in a service-oriented architecture promotes interoperability between service providers and consumers. The adoption of service oriented approach provides WSN users with a unified protocol to access and communicate with the WSN components and developers with a flexible programing model to build efficient and scalable WSN systems. Besides presenting the basic concepts of SOM development and discussing the potential benefits of such approach in building WSM middleware systems, in this chapter we also present a concrete example of a WSN SOM to further illustrate the described features.