RU2190309C2 - Graphic presentation transmission to mobile terminals - Google Patents

Abstract

FIELD: digital mobile communication systems. SUBSTANCE: digital data in the form of graphic presentations are converted into symbol-based data. Converted symbol-based data are then shaped into additional unstructured message-servicing data and conveyed to mobile terminal over separate special-purpose control channel. Messages containing converted symbol-based data are received by mobile terminal and re-converted into binary data which are then displayed on liquid-crystal screen. EFFECT: ability of using active global and personal communication system protocols. 7 cl, 9 dwg

Description

 The invention relates to digital mobile communication systems and, in particular, to the transmission of graphic images for display by a mobile terminal in a digital mobile communication system.

State of the art
With the advent and development of mobile communication systems, telephone subscribers no longer need material wires for exchanging over a communication network. Thanks to the mobility and compactness provided by the mobile terminals, mobile communication systems have become very popular, and mobile system subscribers continue to make up a large and increasing percentage of all new telephone subscribers worldwide.

 With ongoing improvements in display technology, mobile terminals are currently equipped with alphanumeric and graphic displays. Therefore, mobile system subscribers no longer need to remember or associate the called party with a long sequence of numbers. The directory of telephone numbers together with the name or label of the corresponding subscriber can be stored in the storage device of the mobile terminal. When a user wants to contact such a specific number, the user can view the contents of the memory and select a pre-saved name for communication.

 In addition, the global mobile communications system (GSM) and personal communications system (PCS) offer a number of complex and flexible subscriber application systems for mobile system subscribers. One such subscriber application system is the Unstructured Supplementary Service Data (USSD) protocol, which is a “container” mechanism for transporting unstructured or unrecognizable system data (for example, user-defined character messages) to the application system in the mobile terminal. USSD uses a no traffic channel to exchange application layer data between the mobile terminal and the Public Terrestrial Mobile Network (PLMN). Since USSD does not require a voice connection, a user can use a mobile terminal for voice connection, while an application system located in the same mobile terminal simultaneously receives USSD messages via a separate communication channel.

 As an example of the USSD application system, a subscriber attribute management system can be cited. A subscriber of a mobile system may be assigned a number of special features of the subscriber, for example, call transfer, call waiting, and speed dialing. In a non-GSM and non-PCS environment, the user must establish a connection with the operator or exchange device providing the signs and manually call, cancel or modify the signs by sending instructions to the operator or by entering a sequence of service codes and the subsequent necessary information of the subscriber. However, in GMS or PCS, the user can simply call up a menu on the mobile terminal’s liquid crystal display (LCD) screen, move the cursor to the corresponding feature and change the status of the selected feature by calling, canceling or entering the required subscriber information without establishing a voice connection with the serving PLMN. The mobile terminal then automatically transmits the updated information in the form of USSD messages to the PLMN to actually update the status of the selected feature. Another example of the USSD application system is the parallel exchange of user-entered character data during a user conversation with another subscriber. This data may contain the address of the restaurant, advertisements or other text messages for the information of the subscriber who continues the conversation at this time through a separate voice channel.

 One of the drawbacks of the aforementioned GSM or PCS systems is the inability to transmit graphic images, such as still pictures, moving pictures or facsimile images, to a mobile terminal. This is because USSD is a character-based message system. It is standardized for character data between the mobile terminal and PLMN. Graphic images or faxes, in turn, contain binary data or bit data that is incompatible with the character format.

 To transmit graphic images to a mobile terminal, one solution may be to introduce various transfer mechanisms or standards. However, the goal of GSM or PCS is to standardize network environments and protocols to enable mobile system users to freely move and exchange data over a number of different mobile communication systems. Therefore, any new protocol or standard should be reviewed and approved by all participants in the GSM or PCS environment (or committee). Since the current GSM or PCS standard is the result of long and difficult negotiations between many different providers or countries, it is unlikely that a new protocol or mechanism for managing graphic images can be developed in a timely manner.

 US Pat. No. 5,446,678 discloses a system for transmitting graphic data by means of an alphanumeric paging (paging) service. The graphic data is first compressed and then combined into blocks (such as seven-bit character blocks) of a size that can be processed by the paging service. The paging service then transmits this data to the paging receiver, where a separate computer processes it to restore and display the original graphic data.

 Accordingly, it would be advisable to transfer graphic images to the mobile terminal without modifying the existing GSM or PCS protocols or introducing a new transmission mechanism or protocol.

SUMMARY OF THE INVENTION
The present invention provides a system for transmitting graphic images to a mobile terminal connected to a mobile communication system using a character messaging system. Binary data representing a graphic image is converted to a character format. The data in character format is then combined into character messages and transmitted to the mobile terminal through a channel without traffic. The mobile terminal performs the inverse conversion of the received data in a symbol format to the original binary data and processes the data for display.

 In one aspect, the present invention provides a method and apparatus for transmitting graphic images to a mobile terminal by using messages in the form of unstructured supplementary service data (USSD).

 In another aspect, the present invention provides a method and apparatus for transmitting graphic images to a mobile terminal via short message service messages (SMS).

 In another aspect, the present invention provides a method for converting binary graphic image data into character data and transmitting data via USSD and SMS messages.

 In yet another aspect, the present invention discloses a system in which a server application that converts binary graphic image data to character data is located in a mobile system switching center (MSC) serving a particular mobile terminal.

 In yet a further aspect, the present invention discloses a system in which a server application converting binary graphic image data to character data is located in a home position register associated with an MSC serving a particular mobile terminal.

 In yet another aspect, the present invention discloses a system in which a server application that converts binary graphic image data to character data is located in an external node associated with a home position register serving a particular mobile terminal.

 In yet another aspect, the present invention discloses a system in which received symbol data is converted back to the original binary graphic image data and processed for display by a mobile terminal.

Brief Description of the Drawings
The essence of the invention and its objectives are obvious from the following detailed description thereof, illustrated by the accompanying drawings, in which:
figure 1 is a block diagram of a messaging in the format of unstructured supplementary service data (USSD) between the switching center of mobile systems (MSC) and the mobile terminal;
2 is a block diagram of a data format of a USSD message;
figure 3 is a block diagram of a format for the exchange of graphic data (GIF);
FIG. 4 is a flowchart of a conversion method for generating packets of binary graphic image data into USSD messages;
5 is a block diagram of adding GIF data to a USSD message;
FIG. 6 is a block diagram of a server application system transmitting graphic images to a client application system;
7 is a block diagram of a server application located in an MSC serving a specific mobile terminal;
FIG. 8 is a block diagram of a server application in a register of a main area serving a particular mobile terminal;
FIG. 9 is a block diagram of a server application located in an external node connected to a main area register serving a specific mobile terminal.

Detailed Description of Drawings
In FIG. 1 is a block diagram of an unstructured supplementary service data (USSD) message exchange between a mobile terminal 100 and a mobile system switching center (MSC) 130. Signaling for communication services is typically performed in a structured manner. For example, specific predetermined data, formats, and signal names are used to establish a voice connection, to perform switching, and to identify subscriber information when providing service to a subscriber of a mobile system. However, with the introduction of a global mobile communications system (GSM) and a personal communications system (PCS), a number of new and additional improved services are provided to mobile system subscribers. Since these additional services use user-defined data, there are no structured methods for transmitting this data between the GSM Terrestrial Mobile Network (PLMN) GSM application system and the mobile terminal. As a result, a number of unstructured message protocols have been developed for GSM or PCS environments. One such protocol is the Short Message Service (SMS) protocol for transferring information between the PLMN and the mobile terminal. Another protocol is the Unstructured Supplementary Service Data (USSD) protocol, which was introduced to enable the user to interact between the GSN PLMN application systems and the mobile terminal in a hidden manner through a mobile communication network. It is hidden, since neither the MSC nor the mobile terminal are viewing or converting the contents of the transmitted messages.

 Accordingly, USSD or SMS is used when structured functional signaling is not available for additional service. The USSD protocol, for example, provides a transport mechanism for transmitting unstructured data (for example, user-defined text data) to and from the application system located in the destination mobile terminal. An example of such additional services is registration, exclusion, calling or cancellation of subscription services. Another example is a messaging center that interacts with a mobile network to provide subscribers of mobile systems with textual information, such as weather information or stock price information. When a subscriber of the mobile system makes a request to the message service center using a USSD message, the message service center issues the requested information back to the mobile terminal also through USSD messages.

The user of the external node 110 where the specific application system module is located is responsible for the interaction (call procedure) with the mobile terminal 100. The dialogue between the user of the external node 110 and the mobile terminal 100 is performed without converting USSD components to the main area register (HLR) 129 or the mobile switching center systems (MSC) 130 serving the mobile terminal 100. In other words, the HLR 120 and the MSC 130 only transmit USSD components between the respective participants of the aforementioned dialogue (user 110 of the external node and mobile terminal 100) without modification. Whenever the MSC 130 or HLR 120 receives a USSD request initialized by the mobile terminal 100 or a USSD request initialized by the user 110 of the external node, it transmits a request to the USSD control devices 125 and 135. The USSD control device 125 resident in the HLR 120, and the USSD control device 135, resident in the MSC 130, then perform the following tasks to call the application system or send a message to the corresponding application system:
- analysis of the syntax of operations and protocol rules;
- identification of the USSD application system for incoming USSD operations initialized by the mobile terminal;
- transmission of the USSD line and the Data encoding scheme unchanged to the local USSD application system for messages initiated by the mobile terminal;
- transfer of USSD strings and Data encoding schemes unchanged to the mobile terminal for outgoing messages issued by local application systems; and
- the formation of an abnormal shutdown, error components, or components of the execution failure after an instruction received from the USSD application system.

 In FIG. 2 is a block diagram of a USSD or SMS message data format 140. The first eight octets 145 are used to indicate which language, operation, parameter, data length and data sequence are used, and the remaining eighty octets 142 are used to transmit character data, if necessary. Since USSD and SMS are character-based protocols, the contents of section 142 of eighty octets of data are displayed without modification. For example, if an ASCII byte representing the character “c” is transmitted to the mobile terminal, the character “c” is displayed in the next print position on the display device of the mobile terminal. Accordingly, the message service center, for example, can print a string of characters representing a text message, download a string in section 142 of eighty octets of data, and transmit the string to a mobile terminal for display.

 Graphic image data, in turn, is structured differently. To display a graphic image, it is necessary to have a value for each point, or pixel, on the display screen. Therefore, for an elementary screen of 1024 by 750 pixels (such as a fixed-size screen with a black and white image), 768,000 bits are needed to properly fill the available screen space. If the graphic image has a standard format that will work for different screen sizes and different types of machines that support different numbers of characters, other additional information is needed, such as the size of the logical screen. In addition, if the display device is capable of color display, a color value for each position, or pixel, on the screen is also required. Ultimately, you need a binary file with a header field describing the size of the logical screen, a logical color map, and an array of color values for areas of the screen, accompanied by actual images. Also, if the resulting binary is too large, a compression algorithm can be used to “pack” the real images.

 An example of a binary format for representing graphic images is the graphic data exchange (GIF) format developed by CompuServe Incorporated. GIF is CompuServe's standard for defining generic bitmaps and for formatting high-quality, high-resolution graphics that need to be displayed on various graphics hardware. However, as will be described below, other formats are also well known.

 In FIG. 3 is a block diagram of a GIF file format 160. A signature data section 162 defines a GIF version number for the contained image data. The screen descriptor data section 164 defines the overall dimensions of the logical screen that is required to display the contained graphic data. It also defines color display information, background color of the screen, and color saturation information. The global color map data section 166 is optional, but recommended for images that require exact color matching. More specifically, the global color map data section 166 determines the color brightness for various colors of the color spectrum. The image descriptor data section 168 determines the actual placement of the contained image data. Therefore, it determines the start of the image in pixels from the left side of the screen, the start of the image in pixels from the top of the screen, the width of the image in pixels and the height of the image in pixels. Finally, the raster data 170 represents the real image to be displayed. The format of the real image is presented as index color values. Pixels are sequentially stored from left to right for the image line. A series of image lines ultimately constitute a graphic image.

 An embodiment of the present invention is to transmit graphics stored in a binary data file, such as the aforementioned GIF file, to the mobile terminal using existing protocols such as USSD or SNS based on the characters. Using USSD messages, it is not necessary to introduce or develop any new standard or protocol for efficient and accurate transfer of graphic image data to a mobile terminal. However, since the USSD transmission mechanism is a character-based protocol, only seven bits from a byte (one byte consists of eight bits) can be used to transmit the actual data. The remaining one bit is used for your own USSD protocol purposes, such as a stop bit or start bit. As a result, the aforementioned 768000 bits for displaying images on a screen of 1024 • 750 pixels must be divided into 109715 bytes (768000 divided by seven) in order to be in the USSD message. Also, header information such as logical screen size, image descriptor, screen background color and image file format name should be included in the USSD message. After 109715 bytes are received by the mobile terminal, the graphic image data is extracted and converted back to the original format containing a header including attributes of the screen, color and position, followed by real arrays of graphic images.

 4 is a flowchart of a conversion method for generating binary graphic image data packets in USSD messages. As described above, the binary data stream in the GIF file 160 is divided into groups of seven bits 176 and individually reformatted into eight-bit bytes 150. The remaining one bit is used for USSD purposes. Reformatted bytes 150 are then formed into data packets using USSD messages 140. In each USSD message, a header 145 indicates which destination and application system module should receive this character data, and line section 142 contains formatted character data. If the GIF file 160 is too large for a single USSD message, use as many USSD messages as necessary to separately transmit the binary image data. As soon as the mobile terminal receives USSD messages 140, the existing character data is retrieved and re-converted to the original GIF file 160. During the conversion process, the corresponding information 174 and the actual image data 172 for the original GIF file are recomposed.

 Accordingly, in FIG. 5, in accordance with the present invention, a USSD message 140 is provided comprising a GIF file 160 (or part of a GIF file) that is converted to character-based data. As described above, by dividing the bitmap arrays into seven-bit character data so that the contents of the GIF file 160 is compatible with character-based media such as USSD message 140, section 142 of the USSD line can be used to transfer the converted graphic images 160 without the need for another mechanism transmission or protocol.

 Figure 6 presents a block diagram of a server application system transmitting graphic images to a client application system in accordance with the present invention. The server application module 200 performs the conversion of graphic images along with the header information into character-based data and transfers them to the user application system module 200 resident in the mobile terminal. The server application system 200 may store the information requested by the subscriber through a database, or it may receive the requested information from the outside, as shown by line 240, representing a graphic image obtained from, for example, a fax machine. Accordingly, the reception function module 210 in the server application module 200 receives the information requested by the user from external nodes or selects it from the internal memory and transfers it to the conversion function module 220.

 The transform function module 220 receives a graphic image data file, such as a GIF file, and converts the stored binary data along with the header information into character based data, as described above. Then it forms the converted binary data into a series of USSD messages necessary for transferring the whole GIF file. USSD messages containing GIF converted binary data are then passed to the module 230 a forwarding function for transmission to the client application module 300. As shown in FIG. 1, these USSD messages are then transmitted to the USSD message management device resident within the HLR or MSC to physically transmit to the mobile terminal. These USSD messages are physically transmitted in isolation from the TSH traffic channel using a control channel such as an autonomous Specialized Control Channel (SDCCH).

 As soon as the transmitted USSD message is received by the mobile terminal, the USSD message management device located in the mobile terminal transmits messages to the user application module 300. The receive function module 330 in the application system module 300 intercepts the received USSD messages and retrieves the located graphic image data. The extracted data is then passed to the transform function module 320, which, in turn, re-converts the character-based data back to the original GIF data. This is done by extracting the seven-bit data from the eight-bit byte and reorganizing them to represent the original arrays of bit data.

When converting the extracted data, the transform function module 320 first requires setting the format of the contained image file. Graphics file formats may include, but are not limited to:
GIF: graphic data exchange format;
JPEG: standard image compression algorithm;
ACR: ACR-NEMA medical image file;
BMP: standard image file format in MS Windows;
PCX: image file format for color images;
CGN: computer graphics metafile;
HDF: hierarchical data format;
P3D: 3D metafile of the Pittsburgh Supercomputing Center;
RTF: extended text format;
MPEG; Digital video standard developed by a team of cinematography experts;
FLI: animation file format.

 The conversion function module must know which graphic format is used to correctly convert the header information along with the rest of the graphic data. The varieties and number of graphic formats, as shown above, are not limited to the list below. Since the conversion function module 220 located in the server application 200 and the conversion function module 320 located in the user application 300 are matched to recognize each other's converted data, any format can be used. After establishing the current graphic file format, the extracted data is converted accordingly back to their original data format.

 The converted data into GIF or graphic format is then transmitted to the user application function module 310 for display on a display device 340 connected to or located in the mobile terminal. A user application function function module 310 may perform this display task by supplying GIF data to a video standard (VGA) driver 342 associated with the display device 340.

 It is necessary that the user application module 300 is physically located in the mobile terminal 100 in order to receive, convert and display graphic images. On the other hand, the server application module 200 may reside in a number of different nodes in the mobile communication network. In FIG. 7 is a block diagram of a server application 200 located in an MSC 130 serving a particular mobile terminal 100. A server application module 200 located in an MSC 130 selects or receives graphics requested by a user and converts binary data representing the graphics to USSD compatible character-based data. As shown in FIG. 6, such converted data is then loaded into USSD messages and transmitted to the USSD driver in the MSC 130. The MSC 130, in turn, transmits the USSD message to the base station controller 310. The base station controller 310 establishes a specific base station 300 spanning the cellular area currently occupied by the mobile station 100 and transmits a USSD message to this particular base station 300. The base station 300 then transmits the USSD message to the mobile terminal 100 over the communication channel, without traffic such as a standalone Specialized Control Channel (SDCCH). SDCCH is one of the control channels provided by GSM or a PCS network system using time division multiple access (TDMA) technology and commonly used to transmit system signals during call setup before assigning a traffic channel (TSN). For example, subscriber registration and authentication takes place via the SDCCH. As soon as the mobile terminal 100 receives the USSD message, the USSD control device in the mobile terminal 100 looks at the USSD header information associated with the received USSD message and determines which application system should receive the message. As a result, the user application module 310 transmits a USSD message and, in accordance with the present invention, character-based data is retrieved and converted back to its original binary data format. The converted binary data, such as the GIF file, is then input into the VGA driver for display on the LCD device. Using an SDCCH instead of a traffic channel (TSN), the mobile terminal 100 can present graphical images on an LCD device, while the subscriber is simultaneously talking with another user of the communication network.

 In FIG. 8 is a block diagram of a server application 200 located in a primary area register (HLR) 120 serving a mobile terminal 100. As indicated above, the server application system module 200 may be connected to a number of different nodes in a mobile communication network. For network initiated USSD operations, procedures are used for transmitting graphic images similar to those described with reference to FIG. 7. The difference is that the conversion and packet formation is performed in the server application module 200 located in the HLR 120 instead of the MSC 130. However, for operations initiated by the mobile terminal 100, messages are sent to the MSC 130 along the path of the mobile terminal 100 - base station 300 - the base station controller 310 is the MSC 130. The MSC 130 then looks at the header information associated with the received USSD message and determines that the specific application system is not recognized. As a result, the MSC 130 transmits an unrecognized USSD message to the HLR 120. The HLR 120 then determines that the application system defined by the header is located in the HLR 120 itself and transfers the USSD data to the server application module 200. Then, the server application module 200 installs and executes a user request contained in the received USSD data. Such a request, for example, may be for a graphical representation of a local map or region. The server application system module 200, respectively, retrieves information internally or receives it from an external source and transmits the requested graphic image back to the mobile terminal 100, as described above.

 Fig. 9 is a block diagram of a server application module 200 located in an external node 400 connected to a main area register 120 serving a mobile terminal 100. For network initiated USSD operations, procedures for transmitting graphic images similar to those which are described with reference to FIG. The difference is that the conversion and packet generation is performed in the server application module 200 located in the external node 400, instead of the HLR 120. The USSD control devices located in the HLR 120 and the MSC 130 secretly control and route USSD messages generated by the external node 400. For operations initiated by the mobile terminal 100, messages are transmitted to the MSC 130 along the path of the mobile terminal 100 — base station 300 — base station controller 310 — MSC 130. The MSC 130 again looks at the header information associated with the received USSD message, and establishes that a certain application system is not recognized. The MSC 130, in turn, transmits an unrecognized USSD message to the HLR 120. The HLR 120 also looks at the header information associated with the received USSD message, and then determines that the specific application system is also not directly in the HLR 120. The HLR 120 further transmits the USSD message to the external node 400, which is connected to the HLR 120. The external node 400 finally looks at the header information determined by the received USSD message, and passes it to the module 200 of the server application system resident in the external node 400. As described on the above, the server application then installs and duly fulfills the user's request, contained in the received USSD data.

Claims (7)

 1. A binary data exchange system representing a graphic image in a mobile communication system, characterized in that the network node includes a conversion function module for generating a packet of the specified binary data representing the specified graphic image into an SMS service message signal based on short message symbols, or into a message signal of unstructured additional USSD service data, and a sending function module connected to said conversion function module for transmission to the indicated signal of an SMS or USSD message through communication in radiation mode, and the mobile terminal comprises a display, a first receiving function module for receiving said SMS or USSD message signal transmitted by communication in radiation mode, and a second conversion function module connected to said first function module receiving, to extract the generated binary data packet from the received SMS or USSD message signal, and the application system module for displaying the specified binary data representing the specified graph skoe image on the display of said mobile terminal.  2. The system according to claim 1, characterized in that said graphic images are stored in a file in the format for exchanging GIF graphic data.  3. The system according to claim 1, characterized in that said network node comprises a switching center for mobile systems MSC of a mobile communication system currently serving a mobile terminal.  4. The system according to claim 1, characterized in that said network node contains a register of the main HLR region associated with the indicated mobile terminal.  5. The system according to claim 1, characterized in that said network node comprises an external node connected to a register of the main HLR region associated with said mobile terminal.  6. A method of transmitting data representing a graphic image from a mobile communication network to a mobile terminal connected to the indicated mobile communication network, the method comprises the steps of: generating a packet of the specified binary data representing the specified graphic image into a signal of an SMS service message based on symbols short messages, or to a message signal of unstructured additional USSD service data, transmission of the specified SMS or USSD, based on the symbols of the message signal to the specified yl communication terminal via a radiation mode mobile terminal extracting said formed packet of binary data representing said graphic image from a communication signal based on symbols, and displaying a graphic image representing the extracted binary data on the mobile terminal display.  7. The method according to claim 6, characterized in that said binary data representing said graphic images constitutes a file in the format for exchanging graphic data GIF.

Images