Design of a multimedia gateway for mobile devices Raf Hens, Nico Goeminne, Sofie Van Hoecke, Tom Verdickt, Thomas Bouve, Frank Gielen and Piet Demeester Department of Information Technology (INTEC), Ghent University - IMEC, Sint-Pietersnieuwstraat 41, B-9000 Gent, Belgium ABSTRACT Although mobile users are currently offered a lot more capabilities on their mobile devices, they still experience some limitations. They can surf the Internet, read their e-mail and receive MMS messages, but they have limited processing power, storage capacity and bandwidth and are limited in their access to peripherals (e.g. printers). We have designed and implemented a multimedia gateway for mobile devices that reduces these limitations. It gives the mobile devices transparent access to high capacity devices connected to the gateway, which is built around a central, modularly extensible server that can run on any PC or home gateway. It manages two sets of modules: one set offering the actual services and another set handling the IP-based wireless interaction with the client applications on the mobile devices. These modules can be added and removed dynamically, offering new services on the fly. Currently services for storage, printing, domotics and playing music are provided. Others can easily be added later on. This paper discusses the architecture and development, the management of modules, the actual services and their benefits. Besides a proprietary implementation, it also looks into OSGi and how both platforms compare to each other, concerning design, architecture, ease of development, functionality, ... Keywords: multimedia gateway, mobile multimedia services 1. INTRODUCTION Mobile users are currently offered more and more possibilites, with regard to both the capabilities of their mobile devices (mobile phones, PDA’s, . . . ) and the services they can access using their devices. They have screens with higher resolution and full colour capabilities to view the pictures they have taken using their built-in camera. We have seen the introduction of MMS messaging, which allows sending and receiving of all sorts of multimedia. Extended battery life, wireless IP-based communication and other kinds of improvements have made their mobile life a lot easier and pleasurable. Still mobile users experience some limitations and, ironically, the improved functionality introduces new limitations. It is now possible to read e-mail on a mobile phone, but the attachments aren’t really useful in this context. Audio quality isn’t really up to par, documents can’t be printed easily and storage space is very limited. In some environments, like home networks, office buildings or public hot spots where service providers provide an infrastructure, the mobile user’s device can be extended to obtain full PC capabilities. It can use a hifi sound system or the PC’s audio output to play music, it can store data, and it can use a printer facility to print. Unfortunately, there is a gap between having the hardware available and using it from the mobile user’s device. The device needs to be enabled to use many different interconnection protocols; bluetooth, WiFi, etc. Furthermore it needs to detect both hardware and software services on the network. Currently used solutions for detecting these services, such as Jini and UPnP, are hardly usable on small devices. A possible solution is a gateway that offers services transparently to the mobile devices. This way the devices can use the capabilities of the gateway and the peripherals it has access to, with the gateway as a transparent broker system. Further author information: E-mail: Raf.Hens@intec.UGent.be; telephone: +32 9 264 9970; fax: +32 9 264 9960