The Design and Implementation of Multimedia Conference Terminal System on 3G Mobile Phone

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2 2010 International Conference on E-Business and E-Government The Design and Implementation of Multimedia Conference Terminal System on 3G Mobile Phone Li Shangmeng, Shang Yanlei, Ha Jingjing, Chen Junliang The State Key Lab of Networking and Switching Beijing University of Posts and Telecommunications Beijing, China Abstract Economic development and globalization of trade make the cross-region communication more and more frequent. Multimedia conference system supports that individuals or organizations in different places share voice, video and documents to achieve real-time communication. However, the existing multimedia conference terminals lack mobility support. In this paper, we have designed and implemented a Symbianbased multimedia conference terminal system on 3G mobile phone. With this conference terminal system, 3G users can enjoy the high-quality multimedia conference experience and the convenience of mobility at the same time. Keywords-Multimedia Conference System; Multimedia Conference Terminal System; Symbian I. INTRODUCTION With economic development and globalization of trade, cross-region communication becomes increasingly frequent. People need a quick and convenient communication way to meet the daily demands. Multimedia conference system supports people in different places to share voice, video and documents and provides a possibility for people s timely and convenient communications. The multimedia conference technology has been developing along the years. The media of conference system evolves from analog signals to digital signals and from the initial single voice to integrated media format. The network also evolves from the leased line, PSTN, ISDN to LAN and Internet. Although multimedia conference technology has made a great success, the existing multimedia conference terminals like telephone and PC lack mobility support. There is still a long way to achieve the objective of attending multimedia conference anytime and anywhere. Mobile multimedia conference gains more concerns recently. The high-speed data transmission capacity of 3G and the portable, intelligent, personalized mobile terminals provide the possibility to achieve mobile multimedia conference. So it is of great significance to develop a mobile multimedia conference terminal. At present, the mainstream mobile phone operating systems include Symbian, Windows Mobile and Android. Among them, Symbian holds nearly 40% of the market share and becomes most widely used. Under this background, we have designed and implemented a Symbianbased multimedia conference terminal system on 3G mobile phone to facilitate 3G users to attend multimedia conference. The multimedia conference terminal system consists of three function modules: Conference Information Management module, Attend Multimedia Conference module and Set and Help module. The first module implements creating, checking, editing and deleting a conference. The second module supports 3G users to attend multimedia conference. During the conference, user can apply speech, stop speech, switch terminal and switch between video conference and voice conference. The last module includes Set, Help and About functions. With this conference terminal system, 3G users can enjoy the high-quality multimedia conference experience and the convenience of mobility at the same time. The rest of this paper is organized as follows. Section 2 describes the related work. The architecture of the multimedia conference system is presented in Section 3. We implement the Symbian-based mobile multimedia conference terminal system in Section 4. We evaluate the experiment of 3G user attending multimedia conference in Section 5 and conclude in Section 6. II. RELATED WORK Conference system supports two or more individuals or groups in different places to share voice, video and documents through the transmission line and multimedia devices, achieving real-time and interactive communications. Conference system goes through the following periods: telephone conference system, analog conference television, digital conference television and video conference system. With the development of signal processing technology and communication technology, multimedia conference system becomes an effective communication tool in nowadays. Correspondingly, the conference standards have evolved from H.100 [1] series, H.200 [2] series to H.32x series [3] [4] [5] [6]. And H.323 [6] is the most widely used multimedia conference standard. ITU-T adds mobility support for H.324 [3] and gives name H.324M. 3GPP modifies it and proposes 3G-324M. Based on successful experience in IP network, IETF puts forward SIP (Session Initiation Protocol) [7]. Compared with H.323, SIP has the feature of simplicity, opening, and /10 $ IEEE DOI /ICEE

3 expansibility. Thus, 3GPP has designated SIP as the multimedia control protocol in 3G system. Driven by various factors like efficiency and costs, multimedia conference system becomes more and more popular among home and abroad enterprises. Many companies have developed their products to meet the market demands, such as Live Meeting, ichat, PolyCom and Cisco TelePresence [8]. Cisco TelePresence uses the standards and technologies including H.264 codes, SIP, low-latency architecture and lowbandwidth utilization, etc. III. ARCHITECTURE OF MULTIMEDIA CONFERENCE SYSTEM The multimedia conference system in this paper is composed of conference control server and media server. Conference control server is responsible for call process control of multimedia conference service and business billing. Media server is responsible for connecting all the conference participants, mixing voice and video stream and playing IVR (interactive voice response). Multimedia conference system provides the following services: registration, logon, personal account management, creating conference, viewing conference, attending conference, etc. Multimedia conference system has the following characteristics. It is based on public network and provides multi-party conference service for enterprise users and general users. Users are from different networks like PSTN, 3G and Internet. Multimedia conference system supports multiple terminals including PC, telephone, 2G/3G mobile phone. Figure 1 shows the topology architecture of the multimedia conference system. When PC users attend multimedia conference, the conference control server interacts with PC soft client through SIP messages. However, message translation is inevitable for telephone access. No.7 signals go through switches of PSTN and arrive at a gateway, which translates No.7 signals to SIP messages and sends them to multimedia conference system. For 3G mobile phone, the messages pass through BS, MSC and arrive at 3G-324M gateway, which translates 3G-324M messages to SIP messages and sends them to the multimedia conference system. IV. IMPLEMENTATION OF MULTIMEDIA CONFERENCE TERMINAL SYSTEM Based on Symbian S60_3rd_FP1 and Carbide C development platform, we implement the multimedia conference terminal system on 3G mobile phone. A. Framework The multimedia conference terminal system adopts Avkon Multi-View architecture. There are six important views in the conference terminal system. We describe each view respectively as follows. CMyView. It is the main view of the conference terminal system. It displays a function list including Create Conference, Check Conference, Edit Conference, Delete Conference and Attend Conference. The Options menu consists of three function items: Set, Help and About. CConferenceCreatingView. It displays information prompts and blank text boxes. It is used for storage of the newly created conference information, including conference name, call center number, conference ID and conference time. CConferenceListView. It displays all stored conferences in forms of a list, using conference name as an index. It supports users to browse stored conferences. CConferenceInformationView. It displays the It supports users to check stored CConferenceEditingView. It displays information prompts and editable text boxes with conference information. It supports modification of stored CConferenceView. It displays the conference video and conference function label and conference function list box. The conference function list box includes five items: Send Conference ID, Apply Speech, End Speech, Switch Terminal and Switch Mode. B. Function The multimedia conference terminal system is divided into three function modules: Conference Information Management module, Attend Multimedia Conference module, and Set and Help module, as shown in Figure 2. We describe each module respectively. Figure 1. The Topology Architecture of Multimedia Conference System 142

4 conference and voice conference by choosing corresponding function items. 3) Set and Help module This module includes three function items: Set, Help and About. User selects Set to set the conference reminder and historical conference information management, etc. The Help function shows 3G users how to attend multimedia conference and the About function gives the application version and copyright. Figure 2. Symbian View Switch of Conference Terminal System 1) Conference Information Management Module In this module, user can create a conference, check a conference, edit a conference and delete a conference. Create Conference. User inputs specific conference information, including conference name, call center number, conference ID and conference time, and stores the newly created Check Conference. User browses the conference list, finds the interested conference according to the conference name and views the corresponding Edit Conference. User browses the conference list, finds the interested conference and modifies the corresponding Delete Conference. User browses the conference list, finds the interested conference and deletes the corresponding 2) Attend Multimedia Conference module The specific process of 3G user attending the multimedia conference is shown in Figure 2. Firstly, user chooses Attend Conference on the main view of conference terminal system and the system switches to Conference List View. Secondly, user browses conferences and selects the interested conference according to the conference name. Thirdly, the system provides two ways to make the call. One is user directly makes a video or voice call. The other is user views the corresponding conference information, and then makes the video or voice call. After that, the system switches to Conference View and connects the multimedia conference system. On the "Conference View, user presses the conference function label to show or hide the conference function list box in which user can select the appropriate function item. Specifically, user chooses Send Conference ID to join the multimedia conference and then user will receive the conference video. During the conference, user can apply speech, stop speech, switch terminal and switch between video C. Technique in Implementation Key Capture We use key capture mechanism after user choosing Attend Conference item on the main view of multimedia conference terminal system. Firstly, we capture the key sequence and trace the effective path. Once user makes a video or voice call, the key event triggers the conference function label to float out. During the capture of key sequence, we figure out which conference user attends and that user chooses video conference or voice conference. Secondly, we consecutively capture the Selection key to float out or hide the conference function list box. Finally, the Call Termination key event will hide the conference function label. We describe the key capture mechanism next. First, register the key to capture in the application. When user presses the key that has been registered, the keyboard hardware makes an interrupt, which is captured by keyboard driver. It analyzes the key code of the key event and then sends the key event to the window server. Second, window server sends the key event to the application which has registered the key. This application handles key event by calling CAknAppUi::HandleWsEventL(). For key events, CAknAppUi::HandleWsEventL() calls CCoeControl::OfferKeyEventL() for each control on the control stack, beginning with the control at the top until a control consumes it. If no control on the stack consumes the key event, the AppUI::HandleKeyEventL() is called. Note that CCoeControl::OfferKeyEventL() is not called for controls whose ECoeStackFlagRefusesAllKeys flag is set. After handling the key event, the application can forward the key event to another application which currently has the focus. This application handles the key event in the same way as above. Floating Window On the Conference view of multimedia conference terminal system, both the conference function label and the conference function list box adopt floating window mechanism. The floating window is based on Container Class, which inherits CCoeControl Class. Container Class is constructed as follows. Call RWindowGroup::RWindowGroup() to create a window group, which is a hidden window that can receive the keyboard event. Call RWindowGroup::SetOrdinalPosition() to set the window group the highest priority to make the window float out. Call RWindowGroup::EnableReceiptOfFocus() to set the window group to respond to key events. Call CCoeControl::CreateWindowL() to create a window. Add the label and list box controls to the window and set the properties of the controls, such as color, location, and size. For handling key events in the list box, the Container Class must inherit 143

5 MEikListBoxObserver Class and implements the virtual function MEikListBoxObserver::HandleListBoxEventL(). Call CCoeControl::SetRect() to set the location and size of the window. Call CCoeControl::ActivateL() to activate the window. After the construction, put the container into the control stack to handle the key event. V. EVALUATION We have done the experiment of 3G user attending multimedia conference with the conference terminal system on Nokia E 71. The specific process is described as follows. First, 3G user logs on the multimedia conference system to register personal information. The chairman logs on the multimedia conference system to create the conference. After the conference is approved, the multimedia conference system sends all invited 3G users a short message which contains After receiving the short message, user starts the multimedia conference application on Nokia E 71. The main view of the application is shown in Figure 3. User saves conference information in the short message by selecting Create Conference. After that, user chooses Check Conference, Edit Conference and Delete Conference to manage the stored Then, user presses Options menu and chooses Set item to set conference reminder. When receiving the conference reminder, user presses the Arrow Down key to select Attend Conference on the main view, finds the interested conference and makes a video call, which connects the multimedia conference system. User receives voice prompts: "Please send conference ID". User presses the Selection key, chooses Send Conference ID to join the conference and then user receives the conference video, as shown in Figure 4. During the conference, user selects Apply Speech. The application sends applying message to multimedia conference system. After it is approved by the chairman, user receives the voice prompt: Please speak. When finishing speech, user selects End Speech. Then, user chooses Switch Mode to switch video conference to voice conference. After that, user selects Switch Terminal to use the registered telephone to attend conference. Finally, user exits the multimedia conference. Figure 3. The Main View of Multimedia Conference Application Figure 4. The Conference View of Multimedia Conference Application The experiment above has demonstrated that 3G user can manage conference information and attend the multimedia conference. During the conference, user can apply speech, stop speech, switch terminal and switch between video conference and voice conference. With this conference terminal system, 3G User can enjoy the high-quality multimedia conference experience and convenience of mobility at the same time. VI. CONCLUSION Multimedia conference technology has made a great success and multimedia conference system provides a quick and convenient communication way, but the existing multimedia conference terminals lack mobility support. In this paper, we have designed and implemented a Symbian-based mobile multimedia conference terminal. We have shown that with this multimedia conference terminal, 3G users can enjoy the high-quality multimedia conference experience and the convenience of mobility at the same time. ACKNOWLEDGMENT We would like to thank He Qian, Chen Shengyang and Deng Miaoting for their assistance and comments. This work is supported by the National Grand Fundamental Research 973 Program of China (Grant No.2007CB307103) and Important Science &Technology Specific Project of Guizhou Province (Grant No.[2007]6017). REFERENCES [1] ITU-T H.100. Visual telephone systems, 1988 [2] ITU-T H.200. Framework for Recommendations for audiovisual services, 1993 [3] ITU-T H.324. Terminal for low bit-rate multimedia communication, 2009 [4] ITU-T H.320. Narrow-band visual telephone systems and terminal equipment, 2004 [5] ITU-T H.310. Broadband audiovisual communication systems and terminals, 1998 [6] ITU-T H.323. Packet-based multimedia communications systems, 2006 [7] J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, and E. Schooler. SIP: Session Initiation Protocol. RFC3261, IETF, 2002, 6 [8] ducts_genericcontent0900aecd80546cd0.html 144