KR20020020136A - A video conference system based on moblie terminal - Google Patents

Abstract

PURPOSE: A video conference system based on the mobile terminal is provided to perform a video conference during movement by realizing a video conference system using a mobile terminal. CONSTITUTION: A video conference system based on the mobile terminal includes a first mobile terminal(210a), a server(220) and a second mobile terminal(210b). The first mobile terminal requests video conference by carrying out a prescribed video conference application program according to a first user's manipulation. The server carries out a log-in process and sends a registration list if receiving a log-in request of a user from each mobile terminal, and grasps a second user's connection condition, notifies the connection condition to the first mobile terminal and requests the second user to connect if receiving connection with the second user from the first mobile terminal. The second mobile terminal transmits acception signal according to the second user's manipulation if the server requests connection to provide a function for video conference with the first mobile terminal.

Description

A video conference system based on moblie terminal}

The present invention relates to a video conferencing system, and more particularly, to a mobile terminal based video conferencing system operating in a mobile communication environment using an IMT2000 communication network.

Recently, as the interest in the Internet has increased, Internet video conferencing programs, which were considered exclusively for some computer-related businesses and research institutes, have started to spread. The environment for sharing data is fully equipped.

A terminal of a general video conferencing system, which is widely used in a desktop PC or a dedicated terminal, is an audio input / output device 102, an audio codec 104, a video input / output device 106, and a video codec 108 as shown in FIG. 1. , The audio / video synchronization processing module 110, the system controller 112, the communication protocol 114, the communication network interface 116, and the user interface 118. This basic structure is defined by different protocols in the International Organization for Standardization (ITU-T), depending on the environment of the network used. In other words, video conferencing systems in ISDN are recommended as H.320, H.323 in LAN environments, and H.324 in Generalized Switched Telephone Networks (GSTN).

Referring to FIG. 1, a video conference terminal is a device that enables mutual communication by delivering voice, video, or data in real time. An analog audio signal and a video signal are received, converted into digital, and compressed and encoded. Transmitted to the other party through the other party, the data received from the other party is decoded and output through the speaker or display device as audio and video. In this case, data conferencing services such as file transfer, chat, and electronic blackboard may be additionally provided.

In particular, the video signal terminal proposed by the H.323 recommendation has H.261 and H.263 as the proposed standard for the video codec 108, and G.711 and G.722 as the proposed standard for the audio codec 104. And G.723, and T.120 as a proposed standard for user data application. The system controller 112 performs H.245 control, H.225 call control, H.225 RAS control, and the like. Here, the H.245 protocol controls multimedia information of the videoconferencing system, and the H.225 protocol is a protocol for packetizing and synchronizing audio / video data of the videoconferencing system. Q.931 is a call connection and control protocol of video conferencing system, T.120 is a data transmission and reception protocol such as file transfer and copyboard, and RAS (Register and Admission Service for basic call control) is a user registration of video conferencing system. And resource allocation protocol, RTC / RTCP (Real Time Transfer / RTP Control protocol), transmits real-time data using UDP over TCP / IP network and RTP control protocol, and TKPT transmits real-time data using TCP over TCP / IP network. The protocol, Lightweight Directory Access Protocol (LDAP), is a protocol for retrieving user information (name, region, telephone number) from a videoconferencing information server.

According to the H.323 and related protocols, the following operations are performed to conduct video conferencing with the other party. First, a TCP connection is made between two terminals. The interconnection is then through a well known port. After this connection is made, the requesting terminal sends a SETUP message to the other terminal. The other terminal receiving the setup message completes the H.225 process by sending an ALERTING signal and, if the connection is successful, by sending a CONNECT message. The CONNECT message contains the IP address and port for the H.245 connection. The terminal receiving the connect message interprets the received information and makes a new TCP connection. Afterwards, the codec performance of the audio and video to communicate with each other is exchanged to select a codec that can be performed in common. It then completes the H.225 process by opening logical channels for exchanging data with each other. When you open a logical channel, you know the RTP / RTCP host and port information that will receive the data. If the H.225 / H.245 process is successful, the H.323 terminal sends the CODEC-generated data to the RTP host and port. RTCP examines the sending and receiving of data and generates information to control the codec if it is too slow or fast.

However, such an H.323 terminal has an advantage of being compatible because it is an international standard, but because of its large size, there is a problem that it cannot be used in a mobile terminal environment such as a PDA or an IMT200.

It is an object of the present invention to provide a new videoconferencing system suitable for a mobile environment in order to solve the above problems.

1 is a schematic diagram showing a general video conference terminal;

2 is a schematic diagram showing a network configuration of a video conferencing system according to the present invention;

3 is an example of the PDA shown in FIG.

4 is an example of an IMT2000 terminal shown in FIG. 2;

5 is a flowchart illustrating a procedure for logging in for a video conference according to the present invention;

6 is a flowchart showing a procedure for executing a two-way video conference according to the present invention;

7 is a flowchart illustrating a procedure of processing a video signal according to the present invention.

* Explanation of symbols for main parts of the drawings

200: IMT2000 network 202a, 202b; Base station

210a, 210b: Mobile terminal 212a, 212b: PDA

214a, 214b: IMT2000 terminal 220: server

In order to achieve the above object, the video conferencing system of the present invention is a system for performing a video conference between a first user and a second user through an IMT 2000 network. A first mobile terminal for requesting a video conference by executing an application program; Upon receiving the user's login request from each mobile terminal, perform a predetermined login procedure to send a registration list, and when the first mobile terminal is requested to access the second user, grasp the connection state of the second user. A server notifying a connection state to the first mobile terminal and requesting a connection from the second user; And a second mobile terminal that transmits an acceptance signal according to the operation of the second user when the connection request is received from the server and provides a video conference function with the first mobile terminal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic diagram showing the network configuration of a videoconferencing system according to the present invention, wherein the videoconferencing system of the present invention is based on a mobile terminal 210a of a first videoconferencing user (a) and a second videoconferencing user (b). The mobile terminal b is connected to each other through the IMT2000 network 200 and the server 220 to perform a video conference. The mobile terminals used by the first and second users include PDAs 212a and 212b, which are portable information devices, and IMT2000 terminals 214a and 214b for connecting the PDA to the IMT2000 communication network. It is connected to the IMT2000 network 200 through. Herein, in the embodiment of the present invention, the PDAs 212a and 212b and the IMT2000 terminals 214a and 214b are described in a separate form, but the present invention may be similarly applied to an IMT2000 terminal having a PDA function. In addition, in the embodiment of the present invention has been described only for the PDA, the same can be applied to other portable information devices, such as notebook PC, HPC (Handheld PC), Palm PC and the like.

Referring to FIG. 2, the PDAs 212a and 212b having a video conferencing function may include a microphone 301, an audio coding unit 302, a packet processing unit 303, a video camera 304, and the like. On-board video conferencing including a video coding unit 305, a control unit 306, a depacket unit 307, an audio decoding unit 308, a speaker 309, a video coding unit 310, a display 311 Perform a video conference using the application. As shown in FIG. 4, the IMT2000 terminals 214a and 214b include an MMI unit 401, an audio processing unit 402, an image processing unit 403, a modem unit 404, an IF / RF unit 405, and a control unit. 406, a user authentication unit 407, an external interface unit 408, and a location tracking unit 409.

In FIG. 4, the control unit 406 manages the overall functions and call processing functions of the terminal, and the modem unit 404 spreads and modulates the baseband digital signals of the synchronous and asynchronous methods to the IF / RF unit 405. The IF / RF unit 405 converts the digital signal received from the modem unit 404 into an analog signal, converts the digital signal into a carrier frequency, and transmits the signal to the base station through the antenna. The voice processing unit 402 compresses the voice data input from the PCM codec and transmits it to the modem unit 404 by applying a synchronous EVRC and an asynchronous AMR voice coding technique, and the image processing unit 403 transmits the circuit-based H. 324 / M, packet-based H.323 video coding and transmission. The user authentication unit 407 checks the subscriber by interworking with the network by using the subscriber information stored in the USIM or UIM, and provides voice, video, and data services to which the subscriber is subscribed. It provides a means for users to conveniently connect to peripheral devices by wire or wireless using Bluetooth. The location tracking unit 409 has a built-in GPS receiver to check the location of the subscriber in connection with the network and provides services related to the location of the subscriber.

FIG. 5 is a flow chart illustrating a procedure for logging in for videoconferencing according to the present invention, in which a sequence of operations between user a or b and server 220 is shown. First, a user logs in through a user login process and then performs a video conference according to a video conference system.

Referring to FIG. 5, when a user login process is executed after inputting user information, a user login process is transmitted to a server through a network (501 and 502). The server checks the user who has received the user information, retrieves the registration list, and transmits the registration list back to the user (503 to 506). The terminal of the user receives the registration list information and displays the list information of the registrants (507,508).

FIG. 6 is a flowchart illustrating a procedure for executing a two-way video conference according to the present invention, in which a first user a connects to a second user b through a server 220 and performs a video conference. It is.

After the user logs in, the registration list is selected for the report dialog, and a connection is requested to start video communication (601). When the server receives a video conference request from the first user (a), the server checks the status of the designated talker and notifies the "busy" status if it is connected (604, 606). If it is not connected, the second user (b) requests a connection and notifies the connection request state (605). If the second user receives the connection request, the second user accepts the connection, connects the connection, and starts communication (607, 608). After receiving the connection state, the first user a terminates if the other party is busy. If not, the first user a waits for connection and starts communication when an ACK is received from the other party (610 to 613). ). When the communication is completed, the connection is terminated and terminated (614).

7 is a flowchart illustrating a procedure of processing an image signal according to the present invention.

After successful connection, the video signal flow during video conferencing is performed by capturing, capturing, compressing, packetizing, transmitting, and receiving, depacketizing, restoring, and displaying the receiver.

In FIG. 7, in the photographing process 701, a video conference user is photographed through an image capturing camera such as a CCD or a CMOS, and in the capturing process 702, images are stored in a memory in units of frames. In the compression process 703, the image frame stored in the memory is compared with the previous frame to be compressed (MPEG) encoded. In the packetization process 704, the image data compressed by STP or H.225.0, RTP / RTCP, etc. After configuring in the form of a packet that can be transmitted, the data is transmitted in a standard protocol such as TCP / IP, PPP in the transmission process (705). At this time, the IMT2000 terminal is physically connected to communicate with the other party through the IMT2000 network.

The receiving end on the other side is generally the reverse of the transmitting end.

In the receiving process 706, data is received using a standard transmission protocol such as TCP / IP or PPP. In the depacketizing process 707, data packetized by STP or H.225.0, RTP / RTCP, etc., is used as image frame data. Restore In the reconstruction process 708, the compressed image frame is reconstructed to a standard image format of YUV or RGB format, and the image data is displayed on the LCD display device.

As described above, according to the present invention, a video conferencing system can be implemented using a portable terminal such as a PDA or an embedded IMT2000 terminal, an HPC, and the like. In particular, it is possible to implement a video conferencing system at a low cost by implementing a video conferencing function compactly suited for a wireless environment.

Claims (4)

A system for performing a video conference between a first user and a second user through an IMT 2000 network, A first mobile terminal configured to request a video conference by executing a video conference application program according to the operation of the first user; Upon receiving the user's login request from each mobile terminal, perform a predetermined login procedure to send a registration list, and when the first mobile terminal is requested to access the second user, grasp the connection state of the second user. A server notifying a connection state to the first mobile terminal and requesting a connection from the second user; And And a second mobile terminal for providing a video conference function with the first mobile terminal by transmitting an acceptance signal according to the operation of the second user when the connection is requested from the server. . The videoconferencing system of claim 1, wherein the first and second mobile terminals comprise an IMT2000 terminal for wirelessly connecting to the IMT2000 network and a portable information terminal connected to the IMT2000 terminal. . 3. The mobile terminal based video conferencing system according to claim 2, wherein the portable information terminal is one of a PDA, an HPC, and a palm PC. The method of claim 3, wherein the PDA, MIC; An audio coding unit for compression encoding the output of the microphone; Video cameras; A video coding unit for compression encoding the output of the video camera; A packet processor which receives the output of the audio coding unit and the output of the video coding unit and generates a predetermined packet; A depacket unit for decomposing a packet of the received bitstream; An audio decoding unit for receiving audio data from the depacket unit and decoding the audio data; A speaker for converting the output of the audio decoding unit into sound; A video decoding unit receiving and decoding video data from the depacket unit; And a display for displaying the output of the decoding unit as an image.