Design of hybrid interactive service framework for T-DMB

Abstract

Digitalization of broadcasting system triggered various development of broadcasting technologies. The most widely studied and deployed technical achievement is digital broadcasting system for delivery of multichannel high quality video and audio for fixed reception. In addition to digitalization of television service for fixed reception, study and development of television service for mobile reception has been triggered by fast deployment of mobile internet services. Among various broadcasting system developed for mobile reception, Terrestrial Digital Multimedia Broadcasting (T-DMB) has become the most successfully deployed system. T-DMB is a mobile digital multimedia broadcasting system developed as an extension to Eureka-147 system, which can deliver audio, video, and various digital data to mobile terminals. T-DMB system has been designed to support robust reception on a high speed moving environment and efficient delivery of multiple high quality audiovisual services in a narrow bandwidth channel of 1.5MHz. State-of-the-art technologies such as MPEG-4 Advanced Video Coding (AVC) and MPEG-4 Bit-Sliced Arithmetic Coding (BSAC) have been adopted for compression of video and audio, respectively. Forward error protection technologies widely used for digital television system for fixed device such as Reed Solomon coding and convolutional interleaving mechanism have been employed to improve robustness of reception. One of the major breakthroughs achieved by T-DMB in addition to robust vehicular reception is a system architecture naturally enabling integrated interactive services, which are defined by MPEG-4 System architecture composed of Object Descriptor Framework and Binary Format for Scene (BIFS) technology. T-DMB system architecture has been designed to support various interactive service scenarios including bi-directional interactive services utilizing both T-DMB network and mobile internet. Because mobile phone is the platform mostly implementing T-DMB interactive service, major service scenario is composed of two steps. The first step is browsing the interactive service content delivered through T-DMB network and the second step is consuming mobile internet service connected via Uniform Resource Locator (URL) embedded in the data delivered through the T-DMB network. However, deployment of T-DMB interactive service has two major problems which will be the keys to the successful deployment of interactive services. T-DMB interactive service contents cannot be easily created by hand. In addition, efficient and synchronized delivery of data for interactive service requires sophisticated arrangement of data in time. Therefore, design and implementation with graphical user interface supporting intuitive creation and management of interactive service content is a key to successful deployment of interactive service in T-DMB environment. Providing enhanced interactive service by effectively utilizing advanced environment of smart devices is another key to success of T-DMB interactive services. Smart devices such as smartphones provide largely improved environments for interactive services including large screen with high resolution and high speed mobile internet. Mobile internet services on the smart devices have been dramatically improved by using such environments. Therefore, it is very important to provide enhanced interactive service effectively utilizing advances of the environment of smart devices. As a solution to those problems, in this thesis, two types of service are designed and the results of implementation of systems to realize such services are introduced. The scalable architecture of T-DMB interactive service content is designed to support efficient delivery. The system for T-DMB interactive service with graphical user interface is implemented to support easy and intuitive creation and management of such services. In addition T-DMB hybrid interactive service framework for smart devices has been designed to provide enhanced interactive services including personalized services and location specific services by simultaneously using mobile internet. Implementation of T-DMB hybrid interactive service framework covers systems for creation and the management of the data delivered through T-DMB network and the data for mobile internet. It also provides graphical user interfaces for easy and intuitive creation and management of the T-DMB hybrid interactive services. Based on the analysis on the results of implementation two methods to optimize the usage of MPEG-4 BIFS in mobile phone environments have been proposed. It includes 1) new MPEG-4 BIFS node embedding the compressed image data to optimize the delivery of compressed image data, and 2) new MPEG-4 BIFS node to explicitly define the path for navigation of interactive service menus. T-DMB interactive services designed in this thesis shows two types of convergence services. The first one provides convergence service between digital broadcasting service and mobile internet service by providing links between two services. In this type of convergence service two independent applications are interconnected via URL. The second one, T-DMB hybrid interactive service, provides convergence service with single application utilizing two independent networks. In this type of convergence service integration of data is performed at the convergence application. Therefore, it is not easy to provide fine synchronization between the data from two different delivery channels. A convergence service framework providing complete integration between two networks as hybrid network needs to be studied further.