Abstract
Interoperability is a functionality that facilitates integration amongst disparate devices and systems used by applications. Integration, inter-operability, middleware, and standardization are some of the synonyms or solutions of interoperability. As such, interoperability facilitates timely, efficient, and effective completion of applications, in addition to finding new, smarter, and more adaptive services. Smart cities, like many other environments and applications, suffer from the lack of interoperability, which makes their processing very challenging. The lack of interoperability also leads to ineffectiveness, which is highly undesirable for applications that deal with emergencies or have exceptional requirements. In particular, interoperability is highly desirable in heterogeneous systems. This research presents a comprehensive review of the available methods and ways to deal with the issues related to interoperability. In addition, the article provides a classification of the available solutions to overcome the lack of interoperability. Various methods which claim to provide interoperability, are sorted out according to the domains and context in which they appear. This research has identified the advantages and limitations of the available methods for facilitating interoperability. A comprehensive framework for dealing with Interoperability in different domains is proposed. This framework provides a hybrid approach for dealing with interoperability, which could be regarded as a comprehensive and reliable solution when dealing with smart cities.