Multimedia over Heterogeneous Wireless Networks

The availability of wireless networks and mobile handheld computers with wireless data access, indicates a long-term trend towards ubiquitous computing. Wireless devices are already available at price-point and form factors that make it possible for people to carry them everywhere. They come in the shape of notebooks, handheld computers, Personal Digital Assistants (PDAs), smart phones, phones with PDAs, wearable computers and more. Such devices will have one or more input options such as pen, buttons, keypad, voice and screen. These clients differ in features such as screen size, resolution, color depth, computing power, storage and software. Wireless connections also are quickly evolving to provide a variety of options to users. Wireless connections over large areas (WANs), can connect users with low speeds of a few tens of Kbps through current cellular networks either through their voice service or dedicated data links such as Cellular Digital Packet Data (CDPD). The very low speed barrier of such technologies limits the usefulness of only limited applications such as text only emails and news. In addition to cellular networks users will have higher speed options of a few Mbps connection in their business, residential and public areas such as hotels, coffee shops and airports. This high-speed connection will be provided by high-speed wireless local area networks such as IEEE 802.11a and IEEE 802.11b, wireless personal area networks such as IEEE 802.15 Bluetooth 2.0 or wireless local loops such as IEEE 802.16. In addition to the complexity created by the diverse wireless connection speeds resulting from the use of multiple wireless transmission technologies, we also face the additional challenge of dealing with dynamic wireless bandwidth during an established connection. This dynamic, which occurs due to the wireless channel characteristics, can cause significant degradation of the wireless channel bandwidth or even disconnects. 

To deliver the existing multimedia content to the plethora of mobile wireless devices, transcoding services need to be developed. The idea of converting an object from one form to another - transcoding - is not new and has been implemented by a couple of different research groups and industries. With the emerging telemedicine and digital library technology, multimedia content adaptation with Quality of Service (QoS) and security support, are becoming crucial factors in transcoding architectures for wireless networks. However, few researchers conduct work in these important topics.

Our lab designs and implements transcoding architectures that provide quality of service and security support to heterogeneous clients' devices over diverse wireless networks. We provide below a description of our proof-of-concept prototype as well as a number of ongoing projects on this topic.

 

• Proof of Concept Prototype - Application Level Networking Solutions for MobiLe users (AnMOLe)
• Multi-Device Rendezvous Architecture (MuDRA)
• Ubiquitous Wireless Access to  Digital Libraries  (Collaboration with UC Berkeley)
• Telemedicine
• Mobile Agent Network Access Service (MANAS)
• MOKSHA