Selected topics of mobile multimedia communication services

Due to the recent advancements in the related fields of technologies, mobile multimedia communication is possible with acceptable quality nowadays. Designing suitable multimedia communication services is the next step to both best utilize the advancements and enable effective and increasing use of multimedia in mobile communication. Designing interworkable services is an option to both provide flexibility and complement the services. This dissertation first provides an overview of different mobile multimedia communication services to depict a panoramic view about the subject. Then, it analyzes three potential mobile multimedia communication services of different types, carefully selected based on the context of this dissertation, to lay the foundation for the description that follows. These services are circuit-switched multimedia telephony, Multimedia Messaging Service (MMS), and streaming. MMS has been defined as the solution for mobile multimedia messaging to overcome the known limitations of other existing messaging systems. On the other hand, streaming has been enhanced significantly to make it useful and effective in mobile communication. As the research questions of the dissertation are mostly about MMS and streaming, these are thoroughly analyzed focusing on different related aspects of standardization, implementation, and relevant published research works to find their suitability in the available infrastructures and markets. MMS is also compared with other popular messaging systems – SMS, e-mail and IM. Based on the comparative study, MMS has many advantages. Beside identifying the advantages of MMS, this dissertation also points out couple of its limitations – an inability to handle a message requiring more storage space than available in a terminal, and long retrieval time for a large message. The store-and-forward working principle of MMS requires the storage of the whole message in a terminal before it can be rendered. As MMS has been lately positioned to carry different bandwidth-hungry media with reasonable quality and length, an MMS message can easily become too large for the available storage space of a terminal. Moreover, long retrieval time of a large message can frustratingly keep a user waiting before it is rendered. The limitations are not visible as such in a real-time service, as it does not require storing the whole content before rendering. Interworking with such a service can be used to remove the limitations of MMS. As MMS works in multiple hops between the peer-ends, the interworking should be in terms of using a real-time service within selected hops of MMS transmission, where the limitations are critical. This dissertation considers different important factors to find the optimum scope (extent) of the interworking - using a real-time service in the last hop of MMS transmission to retrieve a message by the recipient terminal. Streaming is found suitable in the dissertation to interwork with MMS to remove the limitations, while circuit-switched multimedia telephony did not appear suitable. The dissertation also finds the solution for the optimum interworking. First, a conceptual framework is designed. Then, three complete implementation solutions are introduced based on the conceptual framework. The solutions are consistent with the basic architecture and the working principles of both MMS and streaming. Here, consistency is important for both preserving user experience and avoiding fragmentation. All these solutions are compared with each other, indicating that none of the solutions has complete advantages over the others. One of the solutions is standardized in the 3rd Generation Partnership Project (3GPP) and the Open Mobile Alliance (OMA), while two solutions have been granted and published as patents. The dissertation also shows a general and flexible end-to-end architecture to accommodate the solutions in different deployment situations. The architecture considers different practical factors like person-to-person messaging, involvement of a content provider and multiple service providers, load balancing and scalability, agreement between a content provider and a service provider, and the use of existing networks for the interworking. MMS has been lately equipped with a new feature - transporting application data. As for example, a chess application in a terminal can use MMS to transport the information about each move on chess-board by remotely located players. This dissertation proposes a few enhancements for the feature to make it more effective. It provides a solution for this feature to be both backward compatible with the MMS solution not supporting this feature, and forward compatible so that a future application can start using the available MMS solution for transporting its data at any time. Compatibility is important not only for smooth deployment of the feature, but also for the future growth of applications, and thus the use of MMS. The solution is partially standardized in the 3GPP and the OMA, while it has been also lately granted and published as a patent. The format of the data communication between MMS and an application is not standardized. As a common format can be helpful in developing applications independently, this dissertation proposes the use of XML (Extensible Markup Language) in this regard. As the extent of data communication between MMS and an application in a terminal is also not defined, this dissertation also shows several examples of XML document to indicate what data should be communicated between an application and MMS