6.3-2
Development of Extended T-DMB Platform Based on WIPI for Interactive Mobile Broadcasting Services Byungjun Bae 1*, Woosuk Kim 1, Choonhyun Ahn 1, Soo In Lee1, and Kyu-Ik Sohng 2 1 2
Broadcasting System Research Group, Electronics and Telecommunications Research Institute, Republic of Korea The School of Electrical Engineering and Computer Science, Kyungpook National University, Republic of Korea * Email:
[email protected]
Abstract — In this paper, we present the architecture of the interactive T-DMB system using the CDMA network for the new interactive broadcasting services. We also propose the structure of the new platform based on WIPI to link broadcasting and telecommunication. We verify the proposed platform with various interactive data contents after implementing it. This shows the possibilities of new interactive services in the digital broadcasting by utilizing the mobility of T-DMB and CDMA.
T-DMB Transmission System Audio Encoder (MUSICAM)
G Service Multiplexer Data Broadcasting Server
Return Channel Server
I. INTRODUCTION T-DMB (terrestrial Digital Multimedia Broadcasting) is a service through which the reception of radio with the clarity and quality of CDs, data broadcasting, and moving images is possible while moving at a high speed. T-DMB, which is based on the European standard, Eureka-147 DAB (Digital Audio Broadcasting), was officially announced as a standard for mobile digital broadcasting in Korea [1], [2]. Recently, TDMB receivers have been developed as a wide range of terminals, including notebook computers, PDAs (Personal Digital Assistants), and cellular phones. Especially, most of manufacturers focus on the T-DMB receivers combining the cellular phone, which uses the CDMA network in Korea, because the two different devices have the similar features of portability and mobility. That means that the interactive TDMB services can be possible by being able to use a mobile telecommunication network as a return channel. In the project like MEMO, various interactive services have ever been tried to test in the mobile environment [3]. In this paper, we present the architecture of the interactive TDMB system using the CDMA network to verify the new interactive broadcasting services. We also propose the structure of the new platform based on WIPI (Wireless Internet Platform for Interoperability) and implement it. It is certainly necessary to link the data from the two different devices, a T-DMB receiver and a cellular phone. The proposed new platform was verified on various interactive service scenarios such as shopping, quiz show and so on. II. INTERACTIVE T-DMB SYSTEM AND RECEIVER Figure 1 shows the interactive T-DMB system based on the Eureka-147 DAB system. This system consists of the T-DMB transmission system including a T-DMB media encoder and a data broadcasting server, a return channel server, and an interactive T-DMB receiver.
0-7803-9459-3/06/$20.00 ¤2006 IEEE
Ensemble Multiplexer
COFDM Encoder
Transmitter
T-DMB Media Encoder
CDMA Network
Interactive T-DMB Platform Interactive T-DMB receiver
Figure 1. Architecture of Interactive T-DMB system. In the T-DMB transmission system, the T-DMB media encoder encodes media sources according to the T-DMB standard and then sends the encoded streams to an ensemble multiplexer as the type of MPEG-2 TSs. The T-DMB standard adopts MPEG-4 AVC (Advanced Video Coding) in video and MPEG-4 BSAC (Bit Sliced Arithmetic coding) in audio, respectively. The data broadcasting server sends data contents, which can sometimes have the URLs for interactivity, to a service multiplexer. This data contents are multiplexed with audio streams (MUSICAM: DAB audio services) in a service multiplexer. The multiplexed streams are multiplexed again with MPEG-2 TSs from the T-DMB media encoder and then transmitted through a COFDM encoder and a transmitter. Exactly, T-DMB transmission system transmits audios, videos, and data one way through the T-DMB network. The return channel server communicates with the interactive T-DMB receiver via the CDMA telecommunication network, and gives users some information whenever there are their requests. The Interactive T-DMB receiver, which is shown in figure 2, basically has the T-DMB receiving module and the CDMA networking module. The T-DMB receiving module has the functions such as T-DMB RF receiving, T-DMB ensemble demultiplexing, SI (Service Information) parsing, A/V decoding, data processing, and A/V displaying for T-DMB services. The CDMA networking module has the functions for CDMA networking. Since it uses the PPP/IP protocols for networking, it is possible for this receiver to interact with the return channel server in the internet world. To make the interactive services linking both modules, this receiver also has a new platform, which is extended from WIPI. T-DMB application, based on it, are implemented and provided users various services.
259
T-DMB Receiving Module
IV. IMPLEMENTATION AND EXPERIMENTS
T-DMB Ensemble Demuxing
T-DMB RF Receiving
A/V Decoding
A/V
Data Processing
Data SI
T-DMB Extended WIPI Platform
T-DMB Application
CDMA Networking Module
Figure 2. Block Diagram of Interactive T-DMB Receiver. III. T-DMB EXTENDED WIPI PLATFORM WIPI is the standard specifications for the mobile platform made by the Mobile Platform Special Subcommittee of the Korea Wireless Internet Standardization Forum (KWISF) [4]. It is necessary for providing an environment for mounting and implementing applications downloaded via the wireless Internet on the mobile communication terminal. And Korea compulsively decided to set WIPI platform on all of the cellular phones in the early 2005 year. Therefore, we should use the WIPI platform to use the T-DMB applications on the proposed receiver having the functions of cellular phone. Since WIPI does not define T-DMB, We newly defined the TDMB extended WIPI platform based on the basic WIPI. Figure 3 illustrates the layered model of the T-DMB extended WIPI platform proposed for interactive T-DMB services.
T-DMB Applications Application Manager Basic API WIPI Run-time Engine WIPI HAL
T-DMB Extended API T-DMB Run-time Engine
To verify the proposed platform and interactive T-DMB services using it, we implemented the data broadcasting server, the return channel server, and the interactive T-DMB receiver, which are shown in Figure 4. This receiver, which has both TDMB receiving module and CDMA module, was implemented on a PC, since it hasn’t been developed yet. We used an external DAB receiver and a commercial CDMA mobile phone as external interface modules. We also implemented T-DMB extended WIPI platform and the integrated browser, which shows A/V and data contents at the same time, on a WIPI emulator. The experiments were performed by utilizing the T-DMB transmission system in our laboratory. Data Broadcasting Server
T-DMB Device Driver
Handset Hardware
T-DMB Hardware
Figure 3. Proposed T-DMB Extended WIPI Platform. WIPI HAL and T-DMB Extended HAL are the interfaces between hardware modules and T-DMB Extended WIPI Platform. These causes T-DMB extended WIPI platform be independently implemented from hardware modules. WIPI HAL offers basic functionalities and accesses to hardware modules for networking. T-DMB Extended HAL also provides functions related to T-DMB services. Using both of WIPI HAL and T-DMB Extended HAL, T-DMB Extended WIPI Platform provides run-time environments and APIs to T-DMB applications. T-DMB applications can also control receiving T-DMB ensembles, displaying MPEG-2 streams, and etc via T-DMB Extended WIPI Platform.
Commercial Cellular phone
Interactive T-DMB Receiver
Figure 4. Implemented Sub-systems. We verified the proposed T-DMB extended WIPI platform as 4 data contents, which were quiz show, shopping, stock information and weather information. Basically, 1 A/V content was transmitted with them. Therefore, the ensembles were configured with 1 A/V content in the stream mode (video: 384kbps, audio: 96kbps) and 4 data contents in the packet mode. The integrated browser in the receiver displays the data contents while the A/V content is playing, as is shown in Figure 4. By using GUI, users get interactive services or more information about broadcasting through CDMA network. V. CONCLUSION
T-DMB Extended HAL
Handset Device Driver
Return Channel Server
In this paper, we propose the novel T-DMB extended WIPI platform for interactive broadcasting services through CDMA network. We also verify the proposed platform by using various interactive data contents. This shows the possibilities of new interactive services in the digital broadcasting by utilizing the mobility of T-DMB and CDMA. However, what are the killer applications for the interactive TDMB services has not known yet. So it is necessary to research about service models in the interactive T-DMB system and technologies which support them. REFERENCES [1] [2]
[3]
[4]
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“Digital Multimedia Broadcasting,” Telecommunications Technology Association in Korea, 2003SG05.02-046, 2003. ETSI EN 300 401 v1.3.3, “Radio Broadcasting Systems; Digital Audio Broadcasting (DAB) to mobile, portable and fixed receivers,” September 2001. Thomas Lauterbach and Matthias Unbehaun, Multimedia Environment for Mobiles(MEMO)-Interactive Multimedia Services to Portable and Mobile Terminals, ACTS Mobile Comm. Summit 97, 1997. KWISF, WIPI 2.0 specification, www.wipi.or.kr
