Title of Invention	DIGITAL COMMUNICATION STSTEM TRANSMITTER,AND DATA SELECTING APPARATUS
Abstract	A digital communication system comprises a transmitter for sequentially transmitting prescribed format data; and plural receivers each comprising a data selecting apparatus for selecting required data from received data group and outputting selected data; the transmitter transmitting data to said receivers in one of a first transmitting mode in which group destination directing information indicating that the data is transmitted to a receiving group consisting of prescribed receivers of the plural receivers, group specifying information for specifying a receiving group of receiving groups to which the data is transmitted, and in-group identifying information for specifying a receiver in an arbitrary receiving group to which the data is transmitted, are included in the data, a second transmitting mode in which the group destination directing information and the group specifying information are included in the data; and a third transmitting mode in which the group destination directing information is included in the data.

Title of Invention

DIGITAL COMMUNICATION STSTEM TRANSMITTER,AND DATA SELECTING APPARATUS

Abstract

A digital communication system comprises a transmitter for sequentially transmitting prescribed format data; and plural receivers each comprising a data selecting apparatus for selecting required data from received data group and outputting selected data; the transmitter transmitting data to said receivers in one of a first transmitting mode in which group destination directing information indicating that the data is transmitted to a receiving group consisting of prescribed receivers of the plural receivers, group specifying information for specifying a receiving group of receiving groups to which the data is transmitted, and in-group identifying information for specifying a receiver in an arbitrary receiving group to which the data is transmitted, are included in the data, a second transmitting mode in which the group destination directing information and the group specifying information are included in the data; and a third transmitting mode in which the group destination directing information is included in the data.

Full Text	1A DIGITAL COMMUNICATION SYSTEM, TRANSMITTER, AND DATA SELECTING APPARATUS FIELD OF THE INVENTION The present invention relates to a digital communication system, a transmitter, and a data selecting apparatus and, more particularly, to a digital communication system, a transmitter, and a data selecting apparatus in which data is transmitted to many receivers for each receiver or for each receiving croup comprising prescribed receivers. BACKGROUND OF THE INVENTION Recently, in many cases, video data, audio data or other data is transmitted and stored in digitized form. In such cases, data is generally divided into pack.ee data comprising plural fields, to be transmitted and stored. Further, in some cases, plural pieces of data is first restructured to be packet data, and then multiplexed to be transmitted through a transmission medium or to be stored in a storage medium. There has been proposed an international standard "MPEG" (Moving Picture Experts Group) for such data structure and multiplexing, and data is transmitted and stored by a method according to a packet data structure of MPEG. Conventionally, in a system in which the multiplexed packet data is used, a receiving equipment 2 selects data to-be-received from the multiplexed packet data. By way of example, a method of transmiting data to each receiver and selecting data in each receiver in digital broadcasting using a data multiplexing method according to MPEG will now be described in brief. In digital broadcasting, in order to transmit key information for decrypting encrypted video/audio data or the like or a mail, data referred tc as "EMM" (Entitlement Management Message) data must be transmitted to specified receivers on an individual basis. In this case, a data structure of the EMM data termed "section" defined in MPEG system is employed. Section data comprises a field of "table-id" indicating that type of data is EMM data, a field indicative of a number of a destination receiver, and a field in which transmitted data is stored. A receiver which receives such data comprises a data selecting apparatus for selecting required data, in which a table-id indicative of EMM data and a receiver individual number are stored. When the receiver receives the section data, the table-id is selected from the received data to check whether this indicates the EMM data. When it indicates the EMM data, the field of the receiver number is selected from the received data to check whether this 3 matches the receiver individual number of the receiver. When a match is found between them, the aata selecting apparatus selects and outputs the section data, whereby it is possible re select data for the receiver. In order to transmit a variety of information with flexibility and only to required receivers, there is a need for a system that groups receivers to transmit data for each group, as well as transmits information to a receiver on an individual basis. There is a further need for the system that transmits the same data to every receiver simultaneously. There is a still further need for the system that selects only receivers being specially 3erved under a contract, and transmits data to these receivers simultaneously. However, using the EMM data transmission method and data selecting method according to the prior art, in the receiving end, every time the table-id field indicates the EMM data, it is checked whether the number of the receiver number field matches a number of the receiver, and only when there is a match between them, the EMM data is selected and received; since transmitted data has a structure in which information indicative of the EMM data is stored in the table-id field, and a destination receiver number is stored in the receiver number field. 4 With the data structure having a receiver number uniquely determined for each receiver, data is transmitted only to one receiver specified by a transmit Ling end, and therefore it is impossible to simultaneously transmit data to a receiver group comprising plural receivers or on a broadcasting service basis. To realize this, it is desired that receivers be specified one by one, and then data be sequentially thereto. Hence, one transmitting end requires several hundreds thousand to several millions of receivers, and accordingly, enormous bandwidth is required of flexible data transmission. Data transmission should be rendered flexibly to offer various services to users or in response to users' demands although this is impossible with restricted bandwidth, leading to degradation in quality of service. In Japanese Patent Application (No. Hei. 7-143117), there is disclosed a communication terminal in which a service group number stored in a receiver which has a right of receiving a program service is compared to a service group number specified in transmitted program data, and when a match is found between them, the program service is received. In this communication terminal, when information for individual ID is received, service type numbers are all checked to detect a match 5 in them, and then it is decided whether there is a match in the individual ID, which causes processing amount to be increased for deciding whether to receive the information for individual ID. SUMMARY OF THE INVENTION It is an object of the present; invention to provide a digital communication system in which data is simultaneously transmitted to every receiver and a prescribed receiver group, as well as to specified receivers, and a transmitter and a data selecting apparatus utilizing this system. Other objects and advantages of the invention will become apparent from the detailed description that follows. The detailed description and specific embodiments described are provided only for illustration since various additions and modifications within the spirit and scope of the invention will be apparent to those of skill in the art from the detailed description. According to a first aspect of the present invention, a digital communication system comprises: a transmitter for sequentially transmitting prescribed format data; and plural receivers each comprising a data selecting apparatus for selecting required data from received data group and outputting selected data; the transmitter transmitting data to said receivers in 6 one of a first transmitting mode in which group destination directing information indicating that the data is transmitted to a receiving group consisting of prescribed receivers of the plural receivers, group specifying information for specifying a receiving group of receiving groups to which the data is transmitted, and in-group identifying information for specifying a receiver in an arbitrary receiving group to which the data is transmitted, are included in the data, a second transmitting mode in which the group destination directing information and the group specifying information are included in the data, and a third transmitting mode in which the group destination directing information is included in the data According to a second aspect of the present invention, in the digital communication system of the first aspect, the transmitter comprises data restructuring means for restructuring data to be transmitted, the data selecting apparatus comprises parameter storage means for presenting plural parameters which are compared to the group destination directing information the in-group identifying information and the group specifying information, respectively; correspondence pattern detecting means for comparing the information stored in the data to the parameters. respectively, to detect correspondence patterns; and output means for selecting data on the basis of the correspondence pattern detected by the correspondence pattern detecting means and outputing selected data According to a third aspect of the present invention, in the digital communication system of the second aspect, the group destination directing information contains a group destination number indicating that, the data to be transmitted is for a receiving group, the group destination directing information contains a specified receiver destination number indicating that the data to be transmitted is for a specified receiver, the parameter storage moans prestores a first parameter to be compared to the group destination number, a second parameter to be compared to the specified receiver destination number and the in-. group identifying information, and a third parameter to be compared to the group specifying information, the correspondence pattern detecting means detects one of first and second correspondence patterns in such a way that the first correspondence pattern is detected when the specified receiver destination number and the in-group identifying information match the second parameter and the group specifying information matches the third parameter in the first transmitting mode, and the second 8 correspondence pattern is detected when the group destination number matches the first parameter and the group specifying information matches the third parameter in the second transmitting mode, and the output means selects data on the basis of one of the first and second correspondence patterns and outputs selected data. According to a fourth aspect of the present invention, in the digital communication system of the third aspect, the group destination directing information contains a specifying number which specifies every receiver indicating that the data to be transmitted is for every receiver, the parameter storage means prestores a fourth parameter to be compared to the specifying number, the correspondence pattern detecting means detects a third correspondence pattern when the specifying number matches the fourth parameter in the third transmitting mode, and the output means selects data on the oasis of the third correspondence pattern and outputs selected data. According to a fifth aspect of the present invention, in the digital communication system of the fourth aspect, the group destination directing information contains a special group number indicating that data to be transmitted is for every receiver which belongs to a special group, the parameter storage means 9 prestores a fourth parameter to be compared to the special group number, the correspondence pattern detecting means detects a fourth correspondence pattern when the special group number matches the fourth parameter in the third transmitting- mode, and the output means selects data on the basis of the fourth correspondence pattern and outputs selected data. Tn the digital communication system so constructed, it is possible to transmit data to a specified receiver, a prescribed receiving group, all receivers, or every receiver which belongs to a special group, and simultaneously to select received data with a small scale circuit in a receiver. According to a sixth aspect of the present invention, a transmitter which restructures data to be in a prescribed format, and which is used in a digital communication system wherein the data is transmitted to plural receivers, the transmitter comprises: data restructuring means for restructuring data to be transmitted in one of a first transmitting mode in which group destination directing information indicating that the data is transmitted to a receiving group consisting of prescribed receivers of the plural receivers, group specifying information for specifying a receiving group of receiving groups to which the data is transmitted, 10 and in-grcup identifying information for specifying a receiver in an arbitrary receiving group tc which the data is transmitted, are included in the data, a second transmitting mode in which the group destination directing information and the group specifying information are included in the data, and a third transmitting mode in which the group destination directing information is included in the data. According to a seventh aspect of the present invention, in the transmitter of the sixth aspect, the group destination directing information in the first transmitting mode contains a specified receiver destination number indicating that the data to be transmitted is for a specified receiver. According to an eighth aspect of the present invention, in the transmitter of the sixth aspect, the group destination directinq information in the second transmitting mode contains a group destination number indicating that the data to be transmitted is for a receiving group. According to a ninth aspect of the present invention, in the transmitter of the sixth aspect, the group destination directing information in the third transmitting mode contains a specifying number which specifies every receiver indicating-that-the data -to be 11 transmitted is for every receiver. According to a tenth aspect of the present invention, in the transmitter of the sixth aspect, the group destination directing information in the third transmitting mode contains a special group number indicating that data to be transmitted is for every receiver which belongs to a special group. In the transmitter so structured, it is possible to restructure data to be received by a specified receiver, data- to be received by receivers which belong to a prescribed receiving group, data to be received by all receivers, or data to be received by every receiver in a special group, to be transmitted, and simultaneously select received data with a small scale circuit in a receiver. According to an eleventh aspect of the present invention, a data selecting apparatus built in a receiver in a digital communication system, which is supplied with prescribed format data as input data, and selects required data from input data group and outputs selected data, the apparatus comprises parameter storage means for prestoring plural parameters which are compared to group destination directing information in the data indicating that the data is transmitted to a receiving group consisting of prescribed receivers of 12 plural receivers, group specifying information in the data for specifying a receiving group of receiving groups to which the data is transmitted, and in-group identifying information in the data for specifying a receiver-in an arbitrary receiving group to which the data is transmitted, respectively; correspondence pattern detecting means for comparing The information stored in the data to the parameters, respectively, to detect correspondence patterns; and output means for selecting data on the basis of the correspondence pattern detected oy the correspondence pattern detecting means and outputting selected data. According to a twelfth aspect of the present invention, in the data selecting apparatus of the eleventh aspect, the group destination di renting information contains a group destination number indicating that the data to be transmitted is for a receiving group, the group destination directing information contains a specified receiver destination number indicating that the data to be transmitted ie for a specified receiver, the parameter storage means prestores a first parameter to be compared to the group destination number, a second parameter to be compared to the specitied receiver destination number and the in-group identifying information, and a third parameter to 13 be compared to the group specifying information, the correspondence pattern detecting means detects one of first and second correspondence patterns in such a way that the first correspondence pattern is detected when the specified receiver destination number and the in-group identifying information match thy second parameter and the group specifying information matches the third parameter, and the second correspondence pattern is detected when the group destination number matches the first parameter and the group specifying information matches the third parameter, and the output means selects-data on the basis o£ one of the first and second correspondence patterns and outputs selected data. According to a thirteenth aspect of the present invention, in the data selecting apparatus of the twelfth aspect, the group destination directing information contains a specifying number which specifies every receiver that indicating the data to be transmitted is for every receiver, the parameter storage means prestores a fourth parameter to be compared to the specifying number, the correspondence pattern detecting means detects a third correspondence pattern when the specifying number matches the fourth parameter, and the output means selects data on the basis of the third correspondence pattern and outputs selected data. 14 According to a fourteenth aspect of the present invention, in the data selecting apparatus of the twelfth aspect, the group destination directing information contains a special group number indicating that data to be transmitted is for every receiver which belongs to a special group, the parameter storage means prestores a fourth parameter to be compared to the special group number, the correspondence pattern detecting means detects a fourth correspondence pattern when the special group number matches the fourth parameter, and the output means selects data on the basis of the fourth correspondence pattern and outputs selected data. Therefore, in the data selecting apparatus so constructed, a specified receiver, a specified receiving group consisting of prescribed receivers of plural receivers, all receivers, or receivers in a special group can select and obtain transmitted data, and simultaneously a receiver can select received data with a ama11 scale circuit. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure l is a diagram showing a communication system according to an embodiment of the present invention. Figure 2 is a diagram shewing structure of data 15 which is transmitted to a specified receiver of the embodiment. Figure 3 is a diagram showing structure of data which is transmitted to a specified group of the embodiment. Figure 4 is a diagram showing structure of data which is transmitted to every receiver of the embodiment Figure 5 is a diagram showing structure of data which is transmitted to a special group of the embodiment. Figure 6 is a diagram showing a construction of a receiver in the communication system according to the embodiment of the present invention. Figure 7 is a diagram showing a data selecting apparatus in the communication system according to the embodiment of the present invention. Figure 8 is a diagram showing a data format of the embodiment or the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Now, a preferred embodiment OF The present invention will be described. First, configuration of a digital communication system according to the present invention is described. Figure 1 illustrates the digital communication system cf the present invention referred to herein by a reference 16 numeral 100. The communication system 100 comprises a transmitter 101, and a receiver 102 for receiving digital data from the transmitter 101. The digital communication system 100 is a digital broadcasting system, for example, and comprises one transmitter 101 to many receivers 102, the transmitter 101 being connected to each of the receivers 102 through a communication network NW. Although the communication network NW is wire herein, it may be wireless. In general, as a data format of data transmitted through the network NW, a "transport stream" defined in MPEG system is employed. The transport stream is a data format in which video or audio, program specification information, EMM data, and so forth are multiplexed in packet. The transport stream is illustrated in figure 8 Referring to figure 8, a transport stream 140 comprises transport stream packets 141 of fixed length. The transport stream packets 141 each comprises a header 141a, an adaptation field 141b, and data 141c, and in the data 141c, video or audio data and so forth are stored. The video or audio data is first stored in a data format illustrated as a PES packet 142, and then stored in the transport stream packet 141. The program specification information and the EMM data die first stored in data formats illustrated as section data 143 1 7 and 144, respectively, and then stored in the transport stream packet 141. The PES packet 142 comprises a header 14 2a and data 142b, and may be stored in plural transport stream packets. The section data 143 and 144 also comprises a header 143a and data 143b, and 144a and 144c, respectively, and plural pieces of section data may be stored in a transport stream packet, or one section data may be stored in plural transport stream packets. The section data 144 also contains destination information 14 4b indicating a receiver by which the EMM data is received. The transmitter 101 comprises a data restructuring unit 103. The data restructuring unit 103 is used for restructuring data to-be-transmitted to be in section -data format according to MPEG. Each receiver 102 comprises a data selecting apparatus 104 for selecting data. The data selecting apparatus 104 comprises a parameter storage unit 105 for prestoring four types of parameters, a correspondence pattern detecting unit 106 for receiving data and comparing the data to the parameter stored in the parameter storage unit 105 to detect a correspondence pattern of them, and an output unit 107 for selecting data on the basis of the correspondence pattern and outputting selected data. The parameters in the parameter storage unit 18 105 can be set by IC card or the Like provided by a transmitting and when the us or subscribes to the digital broadcasting system. The present invention is characterized in that date is broadcast in any of four manners below. That is, in the digital communication system 100, a signal transmitted from the transmitter 101 is (1) received only by a specified receiver 102. (2) received only by a specified receiving group comprising plural receivers 102. (3) received by all receivers 102. (4) received by a special receiving group. Next, this will be described in detail with reference to figures 2 to 5. Figures 2 to 5 illustrate a data structure o£ EMM data 108 to-be-transmitted. Referring to these figures, the EMM data 108 is data which has been restructured by the data restructuring unit 103, and be in a section data format acuorating to MEEDG. The EMM data 108 comprises a table-id field 109, a first field 110, and a second field 111. The table-id field 109 is composed of 8 bits and indicates what type of data section data contains. In this embodiment, in the table-id field 109, "84h" (hereinafter 16 hexadecimal number is represented by "h" 19 at its end) is stored. The "84h" indicates that the section data is the EMM data 108 transmitted to a Specified receiver 102. The first field 110 is composed of 16 bits and contains group destination directing information indicating that the EMM data 10 8 is for a receiving group comprising prescribed receivers of plural receivers, and indicating that to what type of receiving group the EMM. data 108 is transmitted. Further, in-group identifying information indicating that the EMM data 108 is for a specified receiver 102 in an arbitrary group is stored as necessary. More specifically, in a case where the EMM data 108 is for the specified receiver 102, to low order 1 byte of the receiver individual number as the in-group identifying information, a specified receiver destination number indicating that the EMM data 108 is for a specified receiver "FFh" as the group destination directing information is added, and the resulting number is set in the first field of the EMM data 108 (see figure 2) . For example, where a receiver individual number of 4 bytes is "0 1 2 3 4 S 6 7h", "FF67h" is set in the first field 110 of the EMM data 108. This means that a receiver 102 of a receiver individual number whose low order 1 byte is "67h" in an arbitrary 2 0 receiving group is specified as destination. In thus case, "an arbitrary receiving group" is no; a specified one but is any of receiving groups . A receiving group is specified by the group specifying information stored in the second field 111. When the EMM data 108 is transmitted to a receiving group, a group destination number "0000h" is ser as the group destination directing information (see figure 3). This indicates that the EMM data 108 is for a receiving group comprising prescribed receivers of plural receivers rather than to the individual receiver. When the EMM data 108 is for every receiver 102, "000lh" is set as the group destination directing information (see figure 4). When the EMM data 108 is for a special group, "0002h" is set as the group destination directing information (see figure 5),. This indicates the EMM data 108 is transmitted to every receiver 102 which belongs to a special group. It should be noted that the special group consists of receivers 102 under a contract of a special broadcasting service. The second field 111 is composed of a part of data bytes of the EMM data 108. In this embodiment, first 3 bytes are used. In the second field 111, the group specifying information for specifying a receiving group 21 to which the EMM data ICS is transmitted is stored. When the EMM data 108 is for a specified receiving croup, a specified group number "012345h" is set as the group specifying information (see figures 2 and 3) . The "012345h" indicates that the EMM data 108 is transmitted to a receiver in a specified receiving group numbered "012345h" which corresponds to high order 3 bytes of a receiver individual number. As shown in figure 2, low order 1 byte of the receiver EMM data as the in-group identifying information and the specified group number are set, resulting in the EMM data 108 for a receiver specified by the in-group identifying information in a receiving group specified by the specified group number. As shown in figure 3, the group destination number "00000h" and the specified group number w012345h" are set so that the EMM data 108 is for every receiver 102 which belongs to a receiving group specified by the specified group number. As shown in figure 4 , the "00021h" is yet so that the EMM data 106 is for every receiver 102 irrespective of receiving groups. As shown in figure 5, a special group number "0002h" is set so that the EMM data 103 is for every receiver 102 in a specie 1 receiving group under a contract of special, service. As shown in 22 figures 4 and 5, it is not necessary to set the group specifying information. TABLE 1 shows setting for each broadcasting. [TABLE 1] First field 110 Second field 111 FFOOh + Receiver individual Individual Receiver individual number high order 3 Receiver number low order 1 byte bytes OOOOh Receiver individual Receiving (group destination number high order 3 Group number) bytes I Every 000lh (number Receiver specifying every receiver) 0002h Service {special group number) Group Subsequently, the receiver 102 will be described in detail with reference to figure 6. Figure 6 illustrates a construction of the receiver 102. Received broadcast data, for example, data modulated by QPSK, is first demodulated by a digital demodulating circuit 121, and then a packer to-be-received is selected by a packet selecting circuit 122. A packet which contains video or audio data is decrypted by a decrypting circuit 126 when 2 3 the packet is encrypted and can be received by giving key information for decrypting encryption. Then, from the packet, the video or audio data is selected by a packet processing circuit 123, and then temporarily stored in a buffer memory 129 by a memory access circuit 127. Then the video or audio data is sent to a video/ audio decoding circuit 128 at time for regeneration and display, to be expanded therein, and the resulting restored video or audio data is output as NTSC or, PAL video signals, to be displayed. From a packet which contains section data such as program specification information other than EMM data, the section data is selected by the packet processing circuit 123, and sent to a section processing circuit 124. In the section processing circuit 124, section data to-be-received other than the EMM data is selected by a section selecting circuit 125, and then sent to the memory access circuit 127, to be stored in the buffer memory 12 9. The section data stored in the buffer memory 129 is used by a CPU 120 for constructing a program table or a selecting a program for the receiver. Meanwhile, a packet which contains the EMM data 10S is selected by the packet processing circuit 12 3, and sent to the section processing circuit 124 . In the section processing circuit 124, the section selecting 24 circuit 125 and a data selecting apparatus 104 perform selection on the basis of the information stored in respective fields 109, HO, and 111 of the EMM data 108, and then send EMM data to-be-received through the memory access circuit 127 to the buffer memory 129, to be stored therein. In a case where the EMM data stored in the buffer memory 129 indicates information for decrypting video or audio data which can be received, the CPU 12 0 reads the information and forms key information, and sets the same in the decrypting circuit 12 6, thereby allowing decrypting video or audio data. In a case where the EMM data indicates mail information, it is read by the CPU 120 in accordance with operation of the user, and then sent to the video/audio decoding circuit 128, to be displayed. Figure 7 illustrates operation of the data selecting apparatus 104 in figure 6. Referring to figures 1 and 7, the parameter storage unit 10 5 of the data selecting apparatus 104 (see figure 1) can store first to fourth parameters. In this embodiment, "OOOOh", "FF67h" and "012345h" are stored as the first parameter 130, the second parameter 131, and the third parameter 132, respectively. In addition, "0001h" and "0002h" are stored as the fourth parameters 133 and 134, respectively. 25 The correspondence pattern detecting unit 106 of the data selecting apparatus 104 (see figure 1) comprises a first detecting circuit 13F,, a second detecting circuit 136, a third detecting circuit 137, and fourth detecting circuits 138 and 139. The first detecting circuit 135 compares the first parameter 130 "0000h" to the information stored in the first field 110 of the EMM data 108, to detect a match/mismatch between them, and when the match is found, the circuit 135 outputs the input. EMM data 108 . The second detecting circuit 136 compares the second parameter 131 "FF67h" to the information stored in the first field 110 of the EMM data 108, to detect a match/mismatch between them and when the match is found the circuit 136 outputs the input EMM data 108. The third detecting circuit 137 compares the third parameter 132 "0l2345h" to the. 1 information stored in the second field 111 of the EMM data 108 output from the first detecting circuit 135 or the second detecting circuit 136, to detect a match/mismatch between them, and when the match is found, the circuit 137 outputs the input EMM data 108. The fourth detecting circuit 138 compares the fourth parameter 133 "OOOlh" to the information stored in the first field 110 of the received EMM data 108, to detect 26 a match/mismatch between their., and when the march is found, the circuit 138 outputs the input EMM data 108. The fourth defecting circuit 139 compares the fourth parameter 134 w0002h" to the information stored in the first field 110 of the received EMM data 106, to detect a match/mismatch between them, and when the match is found, the circuit 139 outputs the input EMM data 108. In other words, the first to fourth detecting circuits 135 to 139 respectively filter the EMM data 108. When the EMM data is output from at 1 east one of the third and fourth detecting circuits 137, and 133 and 139, the output unit 107 outputs the EMM data 108. As a result, a receiver 102 can receive only EMM data 108 specified for the receiver. Although the fourth detecting circuits 138 and 139 are shown as separate ones in figure 7 to explain operation of the data selecting apparatus 104, they may be the same circuit. More specifically, the EMM data 108 is input to the first , second and forth detecting circuits 100,100 138, and 139. The first, detecting circuit 135 checks whether there is a match between the information stored in the first field 110 and the first parameter 130 "0000h", and when there is the match between them (a correspondence 27 pattern has been detected), the EMM data 108 passes through the first detecting circuit 135. The second detecting circuit 136 checks whether there is a match between the information stored in the first field 110 and the second parameter 131 "F67h", and when there is the match between them, the EMM data 108 passes through the second detecting circuit 136. The EMM data 108 which has passed the first detecting circuit 135 or the second detecting circuit 136 is input to the third detecting circuit 137, which checks whether there is a match between the information stored in the second field 111 and the third parameter 132 "012345h", and when there is the match -between them, the EMM data 10ft passes through the third detecting circuit 137, to the output: unit 107, which outputs the EMM data 108. The fourth detecting circuit 138 checks whether there is a match between the information stored in the first field 110 and the fourth parameter 133 "OOOlh", and when there is the match between them, the EMM data 108 passes through the fourth detecting circuit 133. The fourth detecting circuit 139 checks whether there is a match between the information stored in the first field 110 and the fourth parameter 134 "0002h", and when there is the match between them, the EMM data 28 10b passes through the fourth detecting circuit 139. The output unit 107 outputs the EMM data 10S which has passed through the fourth detecting circuit 138 or 139. Substantially, broadcasting in the communication system 100 will be described. Referring to figure 1 again, the data restructuring unit 10 3 of the transmitter 101 restructures the EMM data 108 to be in one of the formats shown in figures 2 to 5 and transmits the same to the receiver 102, where the EMM data 108 is selected as described below. (1) BROADCASTING FOR SPECIFIED RECEIVER Assume that "01234567h" is set as the number of a specified receiver 102. Nigh order 3 bytes "012345h" of 4 bytes "01234567b" indicate a receiving group to which the specified receiver 102 belongs, and low order 1 byte "67h" indicates the number of the receiver 102 in the receiving group. Therefore, the receiver individual number "FF67h" and the specified group number "012345h" are set in the first field 110. and the second field 111 of the EMM data 108 (see figure 2), respectively. Also assume that, the second parameter 131 "FF67h", and the third parameter 132 "012345h" are respectively set in the parameter storage unit 105 of the data selecting apparatus 104 of one of the plural receivers 102 . Referring to figure 6 again, through the digital 29 demodulating circuit 121, the packet selecting circuit 122, and the pocket processing circuit 123, the EMM data 108 is input to the section processing circuit 124, where the table-in field 10S of the EMM data 108 is checked by the section selecting circuit 125, and it is decided that this is EMM data when "84h", and the EMM data 108 is output to the data selecting apparatus 104. In this embodiment, since "8 4h" is stored in the data identifier field 109, the EMM data 108 is input to the data selecting apparatus 104. Upon receiving the EMM data 108, the data selecting apparatus 104 compares the information stored in the first field 110 to the first parameter 130, the second parameter 131, and the fourth parameters 133 and 134 as already described with reference to figure 7. Since the receiver individual number wFF67h" and the specified group number "012345h" are set in the first field 110 and the second field 111 of the EMM data 108, respectively, the "FF67h" matches the second parameter 131 of the receiver 102, so that the EMM data 108 passes through the second detecting circuit 136. Then, the specified group number of the second field 111 "012345h" matches the third parameter 132 of the receiver 102, so that the EMM data 108 passes through the third detecting circuit,137 to the output unit 107, which outputs the 3 0 EMM data ICQ. As thus described, broadcasting for the specified receiver 102 can he provided. On the other hand, in a case where another number is set in a storage position of the receiver individual number or the specified group number, since it is different from the second parameter 131 or the third parameter 132, the EMM data 10S will not be output from the output unit: 107. (2) BROADCASTING FOR SPECIFIED RECEIVING GROUP Assume that "012345h" is set in receivers 1C2 which belong to a specified group. Therefore, the group destination number "OOOOh" and the specified group number "012346h" are set in the first field 110 and The second field 111 of the EMM data 108 {see figure 3), respectively. Also assume that the first parameter 130 "0000h"f and the third parameter 132 "012345h" are respectively set in the parameter storage unit 105 of the data selecting apparatus 104 of every receiver 102 in the specified group. Upon receiving the EMM data 108, the data selecting apparatus 10 4 compares the information stored in the first field 110 to the first parameter 130, the second parameter 131, and the fourth parameters 133 and 134 as already described with reference to figure 7, Since the group destination number "0000h" and the specified group 31 number "012345b" are set in the first field HO and the second field III of the EMM data 108, respectively, the "0000h" matches the first parameter 130 of the receiver 102, so that the EMM data 108 passes through the first detecting circuit 135. Then, the "C12345h" marches the third parameter 132 of the receiver 102, so that the EMM data 108 passes through the third detecting circuit 1-37 to the output unit 107, which outputs the EMM data 108. This operation is performed by every receiver 102 in the specified group. As thus described, broadcasting for every receiver 102 in the specified group can be provided. On the other hand, in a case where another number is set in a storage position of the group destination number or the specified group number, since it is different from the first parameter 130 or the third parameter 132, the EMM data 108 will not be output from the output unit 107. (3) BROADCASTING FOR ALL RECEIVERS Assume that the number for specifying all receivers "OOOlh" is set in the first field 110 of the EMM data 108 {see figure 4). Also assume that the fourth parameter 133 "OOOlh" is set in the parameter storage 32 apparatus 104 compares the information stored in the first field 110 to the first parameter 130, the second parameter 131, and the fourth parameters 133 and 134 as already described with reference to figure 7. since the "0001h" is set in the first field 110, the "OOOlh" matches the fourth parameter 133 of the receiver 1C2, so that the EMM data 108 passes through the fourth detecting circuit 138 to the output unit 107, which outputs the EMM data 108. Thus, broadcasting for all receivers can be provided., On the other hand, in a case where another number is set in a storage position of the number for specifying all receivers, since it is different from the fourth parameter 133, the EMM data 108 will not be output from the output unit 107 . (4) BROADCASTING FOR SPECIAL RECEIVING GROUP Assume that a special group number "00Q2h" is set in the first field 110 of the EMM data 108 (see figure 5). Also assume that the fourth parameter 134 V0002h" is set in the parameter storage unit 10 5 of the data selecting apparatus 104 of every receiver 102 in the special group. Upon receiving the EMM data 108, the data selecting apparatus 104 compares the information stored in the first field 110 to the first parameter 130, the second parameter 131, and the fourth parameters 133 and 134 as already described with reference to tigure 7. Since the 33 special group number "0C02h" is set in the first field 110, the "OOO2h." matches the fourth parameter 134 of the receiver 102, so that the EMM data 108 passes through the fourth detecting circuit 139 to the output unit, 10, which outputs the EMM data 108. As thus described, broadcasting for the special group, namely, a receiving group comprising receivers under a contract of special service can be provided. On the other hand, in a case where another number is set in a storage position of the special group number, since it is different, from the fourth parameter 134, the EMM data 108 will net be output from the output unit 107. Although the aforementioned four cases have been described as being separate ones, both the broadcasting for all receivers and the broadcasting for the special group become possible provided that both "OOOlh" and "0Q02h" are set in the receiver 102 as the fourth parameters. Furthermore, the numbers or the fourth parameters and the fourth detecting circuits may be increased to set and detect plural kinds of special groups, thereby broadcasting for plural special groups can be provided. Besides, the first field 110 or the receiver indivi dual number is illustrative and not restrictive. In addition, although the EMM data 108 is transmitted in a section data format in the above description, a data selecting apparatus which selects data having another format nay be employed. Yet in addition, although the data transmission in digital broadcasting according to MPEG has beer, described, the data transmission is not restricted thereto, and is applicable to a case where data comprising plural fields is selected. As should be appreciated from the foregoing description, in accordance with the preferred embodiment of the present invention, in digital broadcasting in which various types or data is multiplexed and transmitted, the following data transmission is realized. (1) Data is transmitted to a specified receiver. (2) Data is transmitted to a specified group{receivers are grouped by their individual numbers). (3) Data is transmitted to all receivers simultaneously. (4) Data is transmitted to every receiver in a special group (receivers are grouped on a service basis). As a consequence, destination is specified flexibly, whereby maximum efficiency in use of transmission bandwidth is achieved while significantly reducing the frequency at which the same data is transmitted, as compared with a case where data is transmitted to one receiver. Furthermore, in accordance with the preferred embodiment on the present invention, since a receiver 35 individual, number for identifying a destination receiver of EMM data is determined by group specifying information indicating a receiving group to which the destination receiver belongs, and in-group identifying information for identifying the receiver in the receiving group, and the in-group identifying information is included in the group destination directing information of the EMM data, it is possible to make a decision on the group destination directing information, and simultaneously on whether there is a match in the in-group identifying number. Therefore, when the EMM data is selected by the data selecting circuit, a match in the group specifying information is detected by a" single detecting circuit (third detecting circuit) irrespective of group destination or individual receiver destination, resulting in reduced processing amount, for deriding whether to receive the EMM data. As a consequence, it is possible to select EMM data with a small scale circuit. 36 WE CLAIM X. A digital communication system comprising; A transmitter for sequentially transmitting predetermined format data; and A plurality of receivers each including a data selecting apparatus for selecting required data from received data group and outputting selected data, wherein said transmitter transmits data to said receivers in one of a first transmission mode in which group destination assignment information indicating whether the data is transmitted to a specified receiver of said plurality of receivers, to a group consisting of specified plural receivers, or to all receivers, group specifying information for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information for identifying a receiver to which the data is to be transmitted, in a receiving group which is specified by the group specifying information, are included in the data, and the group destination assignment information in said First transmission mode indicates that the data is transmitted to a specified receiver of said plurality of receivers, a second transmission mode in which the group destination assignment information and the group specifying information are included in the data, and the group destination assignment information in said second transmission mode indicates that the data is transmitted to a group consisting of specified plural receivers, and a third transmission mode in which the group destination assignment information is included in the data, and the group destination assignment information in said third transmission mode indicates that the data is transmitted to all receivers. 2. The digital communication system as claimed in claim 1, wherein said transmitter includes data structuring means for structuring data to be transmitted, and said data selecting apparatus includes: Parameter storage means for prestoring plural parameters which are to be compared to the group destination assignment information, the in-group identification information, and the group specifying information; correspondence pattern detecting means for comparing the information stored in the data to the parameters, respectively, to detect correspondence patterns; and output means for selecting the required data according to the correspondence patterns detected by the correspondence pattern detecting means and outputting the selected data. 3. The digital communication system as claimed in claim 2, wherein said group destination assignment information includes a group destination number indicating that the second transmission mode is used to be transmitted when the data to be transmitted is destined for the group, said group destination assignment information includes a specified receiver destination number indicating that the first transmission mode is used to be transmitted when the data to be transmitted is destined for the specified receiver, said parameter storage means prestores a first parameter to be compared to the group destination number, a second parameter to be compared to the specified receiver destination number and the in-group identification information, and a third parameter to be compared to the group specifying information, said correspondence pattern detecting means: detects transmission being performed in the first transmission mode and indicating that the transmitted in-group identification information is a data to be received, when the specified receiver destination number and the in-group identification information match the second parameter; judges that the first correspondence pattern is detected, when the group specifying information matches the third parameter in the first transmission mode; detects transmission being performed in the second transmission mode, when the group destination number matches the first parameter; and judges that the second correspondence pattern is detected, when the -group specifying information matches the third parameter, and said output means selects the required data according to one of the first and second correspondence patterns and outputs the selected data. 4. The digital communication system as claimed in claim 3, wherein said group destination assignment information includes all specifying numbers indicating that the third transmission mode is used to be transmitted when the data to be transmitted is destined for the all receivers, said parameter storage means prestores a fourth parameter to be compared to the all specifying numbers, said correspondence pattern detecting means detects transmitted being performed in the third transmission mode and judges that being a data to be received, when detecting a third correspondence pattern that the number for specifying al! receivers matches the fourth parameter in the third transmission mode, and said output means selects the required data according to the third correspondence pattern and outputs the selected data. 5. The digital communication system as claimed in claim 4, wherein said group destination assignment information includes a special group number when the data to be transmitted is destined for all receivers which belong to a special group, when the data to be transmitted is destined for al! receivers which belong to the special group, said parameter storage means prestores a fourth parameter to be compared to the special group number, said correspondence pattern detecting means detects transmission being performed in the third transmission mode and judges that the special group number is a data to be received, when detecting a fourth correspondence 39 pattern that the special group number matches the fourth parameter in the third transmission mode, and said output means selects the required data according to the fourth correspondence pattern and outputs the selected data. 6. A transmitter which is used in a digital communication system wherein data is structured to be in a predetermined format and is transmitted to a plurality of receivers, said transmitter including: data structuring means for structuring data to be transmitted in one of a first data transmission mode in which group destination assignment information indicating whether the data is transmitted to a specified receiver of said plurality of receivers, to a group consisting of specified plural receivers, or to ail receivers, group specifying information for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information for identifying a receiver to which the data is to be transmitted, in a receiving group which is specified by the group specifying information, are included in the data, and the group destination assignment information in said first transmission mode indicates that the data is transmitted to a specified receiver of said plurality of recievers, a second data transmission mode in which the group destination assignment information and the group specifying information are included in the data, and the group destination assignment information in said second transmission mode indicates that the data is transmitted to a group consisting of specified plural receivers, and a third data transmission mode in which the group destination assignment information is included in the data, and the group destination assignment information in said second transmission mode indicates that the data is transmitted to all receivers. 7. The transmitter as claimed in claim 6, wherein said group destination assignment information in the first transmission mode includes a specified receiver destination number indicating that the data to be transmitted is destined for a specified receiver when the data to be transmitted is destined for the specified receiver. 8. The transmitter as claimed in claim 6, wherein said group destination assignment information in the second transmission mode includes a group destination number indicating that the data to be transmitted is destined for a group, when the data to be transmitted is destined for the group. 9. The transmitter as claimed in claim 6, wherein said group destination assignment information in the third transmission mode includes ail specifying numbers indicating that the data to be transmitted is destined for all receivers, when the data to be transmitted is destined for ail receivers, 10. The transmitter as claimed in claim 6, wherein said group destination assignment information in the third transmission mode includes a special group number indicating that the data to be transmitted is destined for all receivers which belong to a special group, when the data to be transmitted is destined for the all receivers which belong to the special group. 11. A data selecting apparatus built in a receiver in digital communication system, which is supplied with predetermined format data as inputs and selects required data from input data group and outputs selected data, said apparatus comprising. Parameter storage means for prsstoring plural parameters which are to be compared to group destination assignment information in trie data indiiit in a receiver in digital communication system, which is supplied with predetermined format data as inputs and selects required data from input data group and outputs selected data, said apparatus comprising, parameter storage means for prestoring plural parameters which are to be compared to group destination assignment information in the data indicating whether the data to be transmitted is transmitted to a specified receiver of said plurality of receivers/ to a group consisting of specified plural receivers, or to al! receivers, group specifying information in the data for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information in the data for identifying a receiver to which the data is to be transmitted, in a receiving group which is specified by the group specifying information ; correspondence pattern detecting means for comparing the information stored in the data to the parameters, respectively, to detect correspondence patterns; and output means for selecting the required data according to the correspondence patterns detected by the correspondence pattern detecting means and outputting the selected data. 12. The data selecting apparatus as claimed in claim 13, wherein said group destination assignment information includes a group destination number indicating that the second transmission mode is used to be transmitted when the data to be transmitted is destined for the group, said group destination assignment information includes a specified receiver destination number indicating that the first transmission mode is used to be transmitted when the data to be transmitted is destined for the specified receiver, said parameter storage means prestores a first parameter to be compared to the group destination number, a second parameter to be compared to the specified receiver destination number and the in-group identification information, and a third parameter to be compared to the group specifying information,. said correspondence pattern detecting means: detects transmission being performed in the first transmission mode and indicating that the transmitted in-group identification information is a data to be received, when the specified receiver destination number and the in-group identification information match the second parameter; judges that the first correspondence pattern is detected, when the group specifying information matches the third parameter; detects transmission being performed in the second transmission mode, when the group destination number matches the first parameter; and judges that the second correspondence pattern is detected, when the group specifying information matches the thirds parameter, and said output means selects the required data according to one of the first and second correspondence patterns and outputs the selected data. 13. The data selecting apparatus as claimed in claim 12, wherein said group destination assignment information includes all specifying numbers indicating that the third transmission mode used to be transmitted, when the data to be transmitted is destined for the a!! receivers, said parameter storage means prestores a fourth parameter to be compared to the all specifying numbers, said correspondence pattern detecting means detects transmission being performed in the third transmission mode and judges that being 3 data to be received, when detecting a third correspondence pattern that the number for specifying at receivers matches the fourth parameter, and said output means selects the required data according to the third correspondence pattern and outputs the selected data. 14, The data selecting apparatus as claimed in claim 12, wherein said group destination assignment information includes a special group number indicating that the data to be transmitted is destined for a!! receivers which belongs to a special group, when the data to be transmitted is destined for the all receivers which belong to the special group, 43 said parameter storage means prestores a fourth parameter to be compared to the special group number, said correspondence pattern detecting means detects transmission being performed in the third transmission mode and judges that the special group number is a data to be received, when detecting a fourth correspondence pattern that the special group number matches the fourth parameter, and said output means selects the required data according to the fourth correspondence pattern and outputs the selected data. 15, A digital communication system comprising: a transmitter for sequentially transmitting predetermined format data; and A plurality of receivers each including a data selecting apparatus for selecting required data from received data group and outputting selected data, wherein said transmitter transmits data to said receivers in one of the first transmission mode in which group destination assignment information directing which transmission mode is used among the first transmission mode, the second transmission mode, and the third transmission mode, the second transmission mode, and the third transmission mode, to transmit the data, group specifying information for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information for identifying a receiver in an arbitrary receiving group to which the data is to be transmitted, are included in the data, the second transmission mode in which the group destination assignment information and the group specifying information are included in the data, and the third transmission mode in which the group destination assignment information is included in the data. 16. A transmitter which is used in a digital communication system wherein data is structured to be in a predetermined format and is transmitted to a plurality of receivers, said transmitter including: data structuring means for structuring data to be transmitted in one of a first data transmission mode in which group destination assignment information directing which transmission mode is used among the first transmission mode, the second transmission mode, and the third transmission mode to transmit the data, group specifying information for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information for identifying a receiver in an arbitrary receiving group which the data is to be transmitted, are included in the data, the second data transmission mode in which the group destination assignment information and the group specifying information are included in the data, and the third data transmission mode in which the group destination assignment information is included in the data. A digital communication system comprises a transmitter for sequentially transmitting prescribed format data; and plural receivers each comprising a data selecting apparatus for selecting required data from received data group and outputting selected data; the transmitter transmitting data to said receivers in one of a first transmitting mode in which group destination directing information indicating that the data is transmitted to a receiving group consisting of prescribed receivers of the plural receivers, group specifying information for specifying a receiving group of receiving groups to which the data is transmitted, and in-group identifying information for specifying a receiver in an arbitrary receiving group to which the data is transmitted, are included in the data, a second transmitting mode in which the group destination directing information and the group specifying information are included in the data; and a third transmitting mode in which the group destination directing information is included in the data.

Full Text

1A
DIGITAL COMMUNICATION SYSTEM, TRANSMITTER, AND DATA
SELECTING APPARATUS FIELD OF THE INVENTION
The present invention relates to a digital communication system, a transmitter, and a data selecting apparatus and, more particularly, to a digital communication system, a transmitter, and a data selecting apparatus in which data is transmitted to many receivers for each receiver or for each receiving croup comprising prescribed receivers.
BACKGROUND OF THE INVENTION
Recently, in many cases, video data, audio data or other data is transmitted and stored in digitized form. In such cases, data is generally divided into pack.ee data comprising plural fields, to be transmitted and stored. Further, in some cases, plural pieces of data is first restructured to be packet data, and then multiplexed to be transmitted through a transmission medium or to be stored in a storage medium. There has been proposed an international standard "MPEG" (Moving Picture Experts Group) for such data structure and multiplexing, and data is transmitted and stored by a method according to a packet data structure of MPEG.
Conventionally, in a system in which the multiplexed packet data is used, a receiving equipment

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selects data to-be-received from the multiplexed packet data. By way of example, a method of transmiting data to each receiver and selecting data in each receiver in digital broadcasting using a data multiplexing method according to MPEG will now be described in brief.
In digital broadcasting, in order to transmit key information for decrypting encrypted video/audio data or the like or a mail, data referred tc as "EMM" (Entitlement Management Message) data must be transmitted to specified receivers on an individual basis. In this case, a data structure of the EMM data termed "section" defined in MPEG system is employed. Section data comprises a field of "table-id" indicating that type of data is EMM data, a field indicative of a number of a destination receiver, and a field in which transmitted data is stored.
A receiver which receives such data comprises a data selecting apparatus for selecting required data, in which a table-id indicative of EMM data and a receiver individual number are stored.
When the receiver receives the section data, the table-id is selected from the received data to check whether this indicates the EMM data. When it indicates the EMM data, the field of the receiver number is selected from the received data to check whether this

3
matches the receiver individual number of the receiver. When a match is found between them, the aata selecting apparatus selects and outputs the section data, whereby it is possible re select data for the receiver.
In order to transmit a variety of information with flexibility and only to required receivers, there is a need for a system that groups receivers to transmit data for each group, as well as transmits information to a receiver on an individual basis. There is a further need for the system that transmits the same data to every receiver simultaneously. There is a still further need for the system that selects only receivers being specially 3erved under a contract, and transmits data to these receivers simultaneously.
However, using the EMM data transmission method and data selecting method according to the prior art, in the receiving end, every time the table-id field indicates the EMM data, it is checked whether the number of the receiver number field matches a number of the receiver, and only when there is a match between them, the EMM
data is selected and received; since transmitted data
has a structure in which information indicative of the EMM data is stored in the table-id field, and a destination receiver number is stored in the receiver number field.

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With the data structure having a receiver number uniquely determined for each receiver, data is transmitted only to one receiver specified by a transmit Ling end, and therefore it is impossible to simultaneously transmit data to a receiver group comprising plural receivers or on a broadcasting service basis. To realize this, it is desired that receivers be specified one by one, and then data be sequentially thereto. Hence, one transmitting end requires several hundreds thousand to several millions of receivers, and accordingly, enormous bandwidth is required of flexible data transmission. Data transmission should be rendered flexibly to offer various services to users or in response to users' demands although this is impossible with restricted bandwidth, leading to degradation in quality of service.
In Japanese Patent Application (No. Hei. 7-143117), there is disclosed a communication terminal in which a service group number stored in a receiver which has a right of receiving a program service is compared to a service group number specified in transmitted program data, and when a match is found between them, the program service is received. In this communication terminal, when information for individual ID is received, service type numbers are all checked to detect a match

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in them, and then it is decided whether there is a match in the individual ID, which causes processing amount to be increased for deciding whether to receive the information for individual ID. SUMMARY OF THE INVENTION
It is an object of the present; invention to provide a digital communication system in which data is simultaneously transmitted to every receiver and a prescribed receiver group, as well as to specified receivers, and a transmitter and a data selecting apparatus utilizing this system.
Other objects and advantages of the invention will become apparent from the detailed description that follows. The detailed description and specific
embodiments described are provided only for illustration since various additions and modifications within the
spirit and scope of the invention will be apparent to those of skill in the art from the detailed description.
According to a first aspect of the present invention, a digital communication system comprises: a transmitter for sequentially transmitting prescribed format data; and plural receivers each comprising a data selecting apparatus for selecting required data from received data group and outputting selected data; the transmitter transmitting data to said receivers in

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one of a first transmitting mode in which group destination directing information indicating that the data is transmitted to a receiving group consisting of prescribed receivers of the plural receivers, group specifying information for specifying a receiving group of receiving groups to which the data is transmitted, and in-group identifying information for specifying a receiver in an arbitrary receiving group to which the data is transmitted, are included in the data, a second transmitting mode in which the group destination directing information and the group specifying information are included in the data, and a third transmitting mode in which the group destination directing information is included in the data
According to a second aspect of the present invention, in the digital communication system of the first aspect, the transmitter comprises data restructuring means for restructuring data to be transmitted, the data selecting apparatus comprises parameter storage means for presenting plural parameters which are compared to the group destination directing
information the in-group identifying information and
the group specifying information, respectively; correspondence pattern detecting means for comparing the information stored in the data to the parameters.

respectively, to detect correspondence patterns; and output means for selecting data on the basis of the correspondence pattern detected by the correspondence pattern detecting means and outputing selected data
According to a third aspect of the present invention, in the digital communication system of the second aspect, the group destination directing information contains a group destination number indicating that, the data to be transmitted is for a receiving group, the group destination directing information contains a specified receiver destination number indicating that the data to be transmitted is for a specified receiver, the parameter storage moans prestores a first parameter to be compared to the group destination number, a second parameter to be compared to the specified receiver destination number and the in-. group identifying information, and a third parameter to be compared to the group specifying information, the correspondence pattern detecting means detects one of first and second correspondence patterns in such a way that the first correspondence pattern is detected when the specified receiver destination number and the in-group identifying information match the second parameter and the group specifying information matches the third parameter in the first transmitting mode, and the second

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correspondence pattern is detected when the group destination number matches the first parameter and the group specifying information matches the third parameter in the second transmitting mode, and the output means selects data on the basis of one of the first and second correspondence patterns and outputs selected data.
According to a fourth aspect of the present invention, in the digital communication system of the third aspect, the group destination directing information contains a specifying number which specifies every receiver indicating that the data to be transmitted is for every receiver, the parameter storage means prestores a fourth parameter to be compared to the specifying number, the correspondence pattern detecting means detects a third correspondence pattern when the specifying number matches the fourth parameter in the third transmitting mode, and the output means selects data on the oasis of the third correspondence pattern and outputs selected data.
According to a fifth aspect of the present invention, in the digital communication system of the fourth aspect, the group destination directing information contains a special group number indicating that data to be transmitted is for every receiver which belongs to a special group, the parameter storage means

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prestores a fourth parameter to be compared to the special group number, the correspondence pattern detecting means detects a fourth correspondence pattern when the special group number matches the fourth parameter in the third transmitting- mode, and the output means selects data on the basis of the fourth correspondence pattern and outputs selected data.
Tn the digital communication system so constructed, it is possible to transmit data to a specified receiver, a prescribed receiving group, all receivers, or every receiver which belongs to a special group, and simultaneously to select received data with a small scale circuit in a receiver.
According to a sixth aspect of the present invention, a transmitter which restructures data to be in a prescribed format, and which is used in a digital communication system wherein the data is transmitted to plural receivers, the transmitter comprises: data restructuring means for restructuring data to be transmitted in one of a first transmitting mode in which group destination directing information indicating that
the data is transmitted to a receiving group consisting
of prescribed receivers of the plural receivers, group specifying information for specifying a receiving group of receiving groups to which the data is transmitted,

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and in-grcup identifying information for specifying a receiver in an arbitrary receiving group tc which the data is transmitted, are included in the data, a second transmitting mode in which the group destination directing information and the group specifying information are included in the data, and a third transmitting mode in which the group destination directing information is included in the data.
According to a seventh aspect of the present invention, in the transmitter of the sixth aspect, the group destination directing information in the first transmitting mode contains a specified receiver destination number indicating that the data to be transmitted is for a specified receiver.
According to an eighth aspect of the present invention, in the transmitter of the sixth aspect, the group destination directinq information in the second transmitting mode contains a group destination number indicating that the data to be transmitted is for a receiving group.
According to a ninth aspect of the present invention, in the transmitter of the sixth aspect, the group destination directing information in the third transmitting mode contains a specifying number which specifies every receiver indicating-that-the data -to be

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transmitted is for every receiver.
According to a tenth aspect of the present invention, in the transmitter of the sixth aspect, the group destination directing information in the third transmitting mode contains a special group number
indicating that data to be transmitted is for every
receiver which belongs to a special group.
In the transmitter so structured, it is possible to restructure data to be received by a specified receiver, data- to be received by receivers which belong to a prescribed receiving group, data to be received by all receivers, or data to be received by every receiver in a special group, to be transmitted, and simultaneously select received data with a small scale circuit in a
receiver.
According to an eleventh aspect of the present
invention, a data selecting apparatus built in a receiver in a digital communication system, which is supplied with prescribed format data as input data, and selects required data from input data group and outputs selected data, the apparatus comprises parameter storage means for prestoring plural parameters which are compared to group destination directing information in the data indicating that the data is transmitted to a receiving group consisting of prescribed receivers of

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plural receivers, group specifying information in the data for specifying a receiving group of receiving groups to which the data is transmitted, and in-group identifying information in the data for specifying a receiver-in an arbitrary receiving group to which the data is transmitted, respectively; correspondence pattern detecting means for comparing The information stored in the data to the parameters, respectively, to detect correspondence patterns; and output means for selecting data on the basis of the correspondence pattern detected oy the correspondence pattern detecting means and outputting selected data.
According to a twelfth aspect of the present invention, in the data selecting apparatus of the eleventh aspect, the group destination di renting
information contains a group destination number indicating that the data to be transmitted is for a
receiving group, the group destination directing information contains a specified receiver destination number indicating that the data to be transmitted ie for a specified receiver, the parameter storage means
prestores a first parameter to be compared to the group destination number, a second parameter to be compared to
the specitied receiver destination number and the in-group identifying information, and a third parameter to

13
be compared to the group specifying information, the correspondence pattern detecting means detects one of first and second correspondence patterns in such a way that the first correspondence pattern is detected when the specified receiver destination number and the in-group identifying information match thy second parameter and the group specifying information matches the third parameter, and the second correspondence pattern is detected when the group destination number matches the first parameter and the group specifying information matches the third parameter, and the output means selects-data on the basis o£ one of the first and second correspondence patterns and outputs selected data.
According to a thirteenth aspect of the present invention, in the data selecting apparatus of the twelfth aspect, the group destination directing information contains a specifying number which specifies every receiver that indicating the data to be transmitted is for every receiver, the parameter storage means prestores a fourth parameter to be compared to the specifying number, the correspondence pattern detecting means detects a third correspondence pattern when the specifying number matches the fourth parameter, and the output means selects data on the basis of the third correspondence pattern and outputs selected data.

14
According to a fourteenth aspect of the present invention, in the data selecting apparatus of the twelfth aspect, the group destination directing information contains a special group number indicating that data to be transmitted is for every receiver which belongs to a special group, the parameter storage means prestores a fourth parameter to be compared to the special group number, the correspondence pattern detecting means detects a fourth correspondence pattern when the special group number matches the fourth parameter, and the output means selects data on the basis of the fourth correspondence pattern and outputs selected data.
Therefore, in the data selecting apparatus so
constructed, a specified receiver, a specified receiving
group consisting of prescribed receivers of plural
receivers, all receivers, or receivers in a special
group can select and obtain transmitted data, and
simultaneously a receiver can select received data with
a ama11 scale circuit.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure l is a diagram showing a communication system according to an embodiment of the present invention.
Figure 2 is a diagram shewing structure of data

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which is transmitted to a specified receiver of the embodiment.
Figure 3 is a diagram showing structure of data which is transmitted to a specified group of the embodiment.
Figure 4 is a diagram showing structure of data which is transmitted to every receiver of the embodiment
Figure 5 is a diagram showing structure of data which is transmitted to a special group of the embodiment.
Figure 6 is a diagram showing a construction of a receiver in the communication system according to the embodiment of the present invention.
Figure 7 is a diagram showing a data selecting apparatus in the communication system according to the embodiment of the present invention.
Figure 8 is a diagram showing a data format of the embodiment or the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, a preferred embodiment OF The present invention will be described.
First, configuration of a digital communication
system according to the present invention is described. Figure 1 illustrates the digital communication system cf the present invention referred to herein by a reference

16
numeral 100. The communication system 100 comprises a transmitter 101, and a receiver 102 for receiving digital data from the transmitter 101. The digital communication system 100 is a digital broadcasting system, for example, and comprises one transmitter 101 to many receivers 102, the transmitter 101 being connected to each of the receivers 102 through a communication network NW. Although the communication network NW is wire herein, it may be wireless.
In general, as a data format of data transmitted through the network NW, a "transport stream" defined in MPEG system is employed. The transport stream is a data format in which video or audio, program specification information, EMM data, and so forth are multiplexed in packet. The transport stream is illustrated in figure 8 Referring to figure 8, a transport stream 140 comprises transport stream packets 141 of fixed length. The transport stream packets 141 each comprises a header 141a, an adaptation field 141b, and data 141c, and in the data 141c, video or audio data and so forth are stored. The video or audio data is first stored in a data format illustrated as a PES packet 142, and then stored in the transport stream packet 141. The program specification information and the EMM data die first stored in data formats illustrated as section data 143

1 7
and 144, respectively, and then stored in the transport stream packet 141. The PES packet 142 comprises a header 14 2a and data 142b, and may be stored in plural transport stream packets. The section data 143 and 144 also comprises a header 143a and data 143b, and 144a and 144c, respectively, and plural pieces of section data may be stored in a transport stream packet, or one section data may be stored in plural transport stream packets. The section data 144 also contains destination information 14 4b indicating a receiver by which the EMM data is received.
The transmitter 101 comprises a data restructuring unit 103. The data restructuring unit 103 is used for restructuring data to-be-transmitted to be in section -data format according to MPEG. Each receiver 102 comprises a data selecting apparatus 104 for selecting data. The data selecting apparatus 104 comprises a parameter storage unit 105 for prestoring four types of parameters, a correspondence pattern detecting unit 106 for receiving data and comparing the data to the parameter stored in the parameter storage unit 105 to detect a correspondence pattern of them, and an output unit 107 for selecting data on the basis of the correspondence pattern and outputting selected data.
The parameters in the parameter storage unit

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105 can be set by IC card or the Like provided by a transmitting and when the us or subscribes to the digital broadcasting system.
The present invention is characterized in that date is broadcast in any of four manners below. That is, in the digital communication system 100, a signal transmitted from the transmitter 101 is
(1) received only by a specified receiver 102.
(2) received only by a specified receiving group
comprising plural receivers 102.
(3) received by all receivers 102.
(4) received by a special receiving group.
Next, this will be described in detail with
reference to figures 2 to 5.
Figures 2 to 5 illustrate a data structure o£ EMM data 108 to-be-transmitted. Referring to these figures, the EMM data 108 is data which has been restructured by the data restructuring unit 103, and be in a section data format acuorating to MEEDG. The EMM data 108 comprises a table-id field 109, a first field 110, and a
second field 111.
The table-id field 109 is composed of 8 bits and indicates what type of data section data contains. In this embodiment, in the table-id field 109, "84h" (hereinafter 16 hexadecimal number is represented by "h"

19
at its end) is stored. The "84h" indicates that the section data is the EMM data 108 transmitted to a Specified receiver 102.
The first field 110 is composed of 16 bits and contains group destination directing information indicating that the EMM data 10 8 is for a receiving group comprising prescribed receivers of plural receivers, and indicating that to what type of receiving group the EMM. data 108 is transmitted. Further, in-group identifying information indicating that the EMM data 108 is for a specified receiver 102 in an arbitrary group is stored as necessary.
More specifically, in a case where the EMM data 108 is for the specified receiver 102, to low order 1 byte of the receiver individual number as the in-group identifying information, a specified receiver destination number indicating that the EMM data 108 is for a specified receiver "FFh" as the group destination directing information is added, and the resulting number is set in the first field of the EMM data 108 (see figure 2) . For example, where a receiver individual number of 4 bytes is "0 1 2 3 4 S 6 7h", "FF67h" is set in the first field 110 of the EMM data 108. This means that a receiver 102 of a receiver individual number whose low order 1 byte is "67h" in an arbitrary

2 0
receiving group is specified as destination. In thus case, "an arbitrary receiving group" is no; a specified one but is any of receiving groups . A receiving group is specified by the group specifying information stored in the second field 111.
When the EMM data 108 is transmitted to a receiving group, a group destination number "0000h" is ser as the group destination directing information (see figure 3). This indicates that the EMM data 108 is for a receiving group comprising prescribed receivers of plural receivers rather than to the individual receiver.
When the EMM data 108 is for every receiver 102, "000lh" is set as the group destination directing information (see figure 4).
When the EMM data 108 is for a special group, "0002h" is set as the group destination directing information (see figure 5),. This indicates the EMM data 108 is transmitted to every receiver 102 which belongs to a special group. It should be noted that the special group consists of receivers 102 under a contract of a special broadcasting service.
The second field 111 is composed of a part of data bytes of the EMM data 108. In this embodiment, first 3 bytes are used. In the second field 111, the group specifying information for specifying a receiving group

21
to which the EMM data ICS is transmitted is stored. When the EMM data 108 is for a specified receiving croup, a specified group number "012345h" is set as the group specifying information (see figures 2 and 3) . The "012345h" indicates that the EMM data 108 is transmitted to a receiver in a specified receiving group numbered "012345h" which corresponds to high order 3 bytes of a receiver individual number.
As shown in figure 2, low order 1 byte of the receiver EMM data as the in-group identifying information and the specified group number are set, resulting in the EMM data 108 for a receiver specified by the in-group identifying information in a receiving group specified by the specified group number. As shown in figure 3, the group destination number "00000h" and the specified group number w012345h" are set so that the EMM data 108 is for every receiver 102 which belongs to a receiving group specified by the specified group number.
As shown in figure 4 , the "00021h" is yet so that the EMM data 106 is for every receiver 102 irrespective of receiving groups. As shown in figure 5, a special group number "0002h" is set so that the EMM data 103 is for every receiver 102 in a specie 1 receiving group under a contract of special, service. As shown in

22
figures 4 and 5, it is not necessary to set the group specifying information.
TABLE 1 shows setting for each broadcasting.
[TABLE 1]

First field 110
Second field 111

FFOOh +
Receiver individual
Individual
Receiver individual
number high order 3
Receiver
number low order 1 byte
bytes

OOOOh
Receiver individual
Receiving
(group destination
number high order 3
Group
number)
bytes I
Every
000lh (number

Receiver
specifying every

receiver)

0002h

Service
{special group number)

Group

Subsequently, the receiver 102 will be described in detail with reference to figure 6. Figure 6 illustrates a construction of the receiver 102. Received broadcast data, for example, data modulated by QPSK, is first demodulated by a digital demodulating circuit 121, and then a packer to-be-received is selected by a packet selecting circuit 122. A packet which contains video or audio data is decrypted by a decrypting circuit 126 when

2 3
the packet is encrypted and can be received by giving key information for decrypting encryption. Then, from the packet, the video or audio data is selected by a packet processing circuit 123, and then temporarily stored in a buffer memory 129 by a memory access circuit 127. Then the video or audio data is sent to a video/ audio decoding circuit 128 at time for regeneration and display, to be expanded therein, and the resulting restored video or audio data is output as NTSC or, PAL video signals, to be displayed. From a packet which contains section data such as program specification information other than EMM data, the section data is selected by the packet processing circuit 123, and sent to a section processing circuit 124. In the section processing circuit 124, section data to-be-received other than the EMM data is selected by a section selecting circuit 125, and then sent to the memory access circuit 127, to be stored in the buffer memory 12 9. The section data stored in the buffer memory 129 is used by a CPU 120 for constructing a program table or a selecting a program for the receiver.
Meanwhile, a packet which contains the EMM data 10S
is selected by the packet processing circuit 12 3, and sent to the section processing circuit 124 . In the
section processing circuit 124, the section selecting

24
circuit 125 and a data selecting apparatus 104 perform selection on the basis of the information stored in respective fields 109, HO, and 111 of the EMM data 108, and then send EMM data to-be-received through the memory access circuit 127 to the buffer memory 129, to be stored therein. In a case where the EMM data stored in the buffer memory 129 indicates information for decrypting video or audio data which can be received, the CPU 12 0 reads the information and forms key information, and sets the same in the decrypting circuit 12 6, thereby allowing decrypting video or audio data. In a case where the EMM data indicates mail information, it is read by the CPU 120 in accordance with operation of the user, and then sent to the video/audio decoding circuit 128, to be displayed.
Figure 7 illustrates operation of the data selecting apparatus 104 in figure 6. Referring to figures 1 and 7, the parameter storage unit 10 5 of the data selecting apparatus 104 (see figure 1) can store first to fourth parameters. In this embodiment, "OOOOh", "FF67h" and "012345h" are stored as the first parameter 130, the second parameter 131, and the third parameter 132, respectively. In addition, "0001h" and "0002h" are stored as the fourth parameters 133 and 134, respectively.

25
The correspondence pattern detecting unit 106 of the data selecting apparatus 104 (see figure 1) comprises a first detecting circuit 13F,, a second detecting circuit 136, a third detecting circuit 137, and fourth detecting circuits 138 and 139.
The first detecting circuit 135 compares the first parameter 130 "0000h" to the information stored in the first field 110 of the EMM data 108, to detect a match/mismatch between them, and when the match is found, the circuit 135 outputs the input. EMM data 108 .
The second detecting circuit 136 compares the second parameter 131 "FF67h" to the information stored in the first field 110 of the EMM data 108, to detect a
match/mismatch between them and when the match is found
the circuit 136 outputs the input EMM data 108.
The third detecting circuit 137 compares the third parameter 132 "0l2345h" to the. 1 information stored in the second field 111 of the EMM data 108 output from the first detecting circuit 135 or the second detecting circuit 136, to detect a match/mismatch between them, and when the match is found, the circuit 137 outputs the input EMM data 108.
The fourth detecting circuit 138 compares the fourth parameter 133 "OOOlh" to the information stored in the first field 110 of the received EMM data 108, to detect

26
a match/mismatch between their., and when the march is found, the circuit 138 outputs the input EMM data 108.
The fourth defecting circuit 139 compares the fourth parameter 134 w0002h" to the information stored in the first field 110 of the received EMM data 106, to detect a match/mismatch between them, and when the match is found, the circuit 139 outputs the input EMM data 108.
In other words, the first to fourth detecting circuits 135 to 139 respectively filter the EMM data 108. When the EMM data is output from at 1 east one of the third and fourth detecting circuits 137, and 133 and 139, the output unit 107 outputs the EMM data 108. As a result, a receiver 102 can receive only EMM data 108 specified for the receiver.
Although the fourth detecting circuits 138 and 139 are shown as separate ones in figure 7 to explain operation of the data selecting apparatus 104, they may be the same circuit.
More specifically, the EMM data 108 is input to the
first , second and forth detecting circuits 100,100

138, and 139.
The first, detecting circuit 135 checks whether there is a match between the information stored in the first field 110 and the first parameter 130 "0000h", and when there is the match between them (a correspondence

27
pattern has been detected), the EMM data 108 passes through the first detecting circuit 135.
The second detecting circuit 136 checks whether there is a match between the information stored in the first field 110 and the second parameter 131 "F67h", and when there is the match between them, the EMM data 108 passes through the second detecting circuit 136.
The EMM data 108 which has passed the first detecting circuit 135 or the second detecting circuit 136 is input to the third detecting circuit 137, which checks whether there is a match between the information stored in the second field 111 and the third parameter 132 "012345h", and when there is the match -between them, the EMM data 10ft passes through the third detecting circuit 137, to the output: unit 107, which outputs the EMM data 108.
The fourth detecting circuit 138 checks whether there is a match between the information stored in the first field 110 and the fourth parameter 133 "OOOlh", and when there is the match between them, the EMM data 108 passes through the fourth detecting circuit 133.
The fourth detecting circuit 139 checks whether there is a match between the information stored in the first field 110 and the fourth parameter 134 "0002h", and when there is the match between them, the EMM data

28
10b passes through the fourth detecting circuit 139. The output unit 107 outputs the EMM data 10S which has passed through the fourth detecting circuit 138 or 139.
Substantially, broadcasting in the communication system 100 will be described.
Referring to figure 1 again, the data restructuring unit 10 3 of the transmitter 101 restructures the EMM data 108 to be in one of the formats shown in figures 2 to 5 and transmits the same to the receiver 102, where the EMM data 108 is selected as described below. (1) BROADCASTING FOR SPECIFIED RECEIVER
Assume that "01234567h" is set as the number of a specified receiver 102. Nigh order 3 bytes "012345h" of 4 bytes "01234567b" indicate a receiving group to which the specified receiver 102 belongs, and low order 1 byte "67h" indicates the number of the receiver 102 in the receiving group. Therefore, the receiver individual number "FF67h" and the specified group number "012345h" are set in the first field 110. and the second field 111 of the EMM data 108 (see figure 2), respectively. Also assume that, the second parameter 131 "FF67h", and the third parameter 132 "012345h" are respectively set in the parameter storage unit 105 of the data selecting apparatus 104 of one of the plural receivers 102 .
Referring to figure 6 again, through the digital

29
demodulating circuit 121, the packet selecting circuit 122, and the pocket processing circuit 123, the EMM data 108 is input to the section processing circuit 124, where the table-in field 10S of the EMM data 108 is checked by the section selecting circuit 125, and it is decided that this is EMM data when "84h", and the EMM data 108 is output to the data selecting apparatus 104. In this embodiment, since "8 4h" is stored in the data identifier field 109, the EMM data 108 is input to the data selecting apparatus 104.
Upon receiving the EMM data 108, the data selecting apparatus 104 compares the information stored in the first field 110 to the first parameter 130, the second parameter 131, and the fourth parameters 133 and
134 as already described with reference to figure 7. Since the receiver individual number wFF67h" and the
specified group number "012345h" are set in the first field 110 and the second field 111 of the EMM data 108, respectively, the "FF67h" matches the second parameter 131 of the receiver 102, so that the EMM data 108 passes through the second detecting circuit 136. Then, the specified group number of the second field 111 "012345h" matches the third parameter 132 of the receiver 102, so that the EMM data 108 passes through the third detecting circuit,137 to the output unit 107, which outputs the

3 0
EMM data ICQ.
As thus described, broadcasting for the specified receiver 102 can he provided. On the other hand, in a case where another number is set in a storage position of the receiver individual number or the specified group number, since it is different from the second parameter 131 or the third parameter 132, the EMM data 10S will not be output from the output unit: 107. (2) BROADCASTING FOR SPECIFIED RECEIVING GROUP
Assume that "012345h" is set in receivers 1C2 which belong to a specified group. Therefore, the group destination number "OOOOh" and the specified group number "012346h" are set in the first field 110 and The second field 111 of the EMM data 108 {see figure 3), respectively. Also assume that the first parameter 130 "0000h"f and the third parameter 132 "012345h" are respectively set in the parameter storage unit 105 of the data selecting apparatus 104 of every receiver 102 in the specified group.
Upon receiving the EMM data 108, the data selecting apparatus 10 4 compares the information stored in the first field 110 to the first parameter 130, the second parameter 131, and the fourth parameters 133 and 134 as already described with reference to figure 7, Since the group destination number "0000h" and the specified group

31
number "012345b" are set in the first field HO and the second field III of the EMM data 108, respectively, the "0000h" matches the first parameter 130 of the receiver 102, so that the EMM data 108 passes through the first detecting circuit 135. Then, the "C12345h" marches the third parameter 132 of the receiver 102, so that the EMM data 108 passes through the third detecting circuit 1-37 to the output unit 107, which outputs the EMM data 108. This operation is performed by every receiver 102 in the specified group.
As thus described, broadcasting for every receiver 102 in the specified group can be provided. On the other hand, in a case where another number is set in a storage position of the group destination number or the specified group number, since it is different from the first parameter 130 or the third parameter 132, the EMM data 108 will not be output from the output unit 107. (3) BROADCASTING FOR ALL RECEIVERS
Assume that the number for specifying all receivers "OOOlh" is set in the first field 110 of the EMM data 108 {see figure 4). Also assume that the fourth parameter 133 "OOOlh" is set in the parameter storage

32
apparatus 104 compares the information stored in the first field 110 to the first parameter 130, the second parameter 131, and the fourth parameters 133 and 134 as already described with reference to figure 7. since the "0001h" is set in the first field 110, the "OOOlh" matches the fourth parameter 133 of the receiver 1C2, so that the EMM data 108 passes through the fourth detecting circuit 138 to the output unit 107, which outputs the EMM data 108. Thus, broadcasting for all receivers can be provided., On the other hand, in a case where another number is set in a storage position of the number for specifying all receivers, since it is different from the fourth parameter 133, the EMM data 108 will not be output from the output unit 107 . (4) BROADCASTING FOR SPECIAL RECEIVING GROUP
Assume that a special group number "00Q2h" is set in the first field 110 of the EMM data 108 (see figure 5). Also assume that the fourth parameter 134 V0002h" is set in the parameter storage unit 10 5 of the data selecting apparatus 104 of every receiver 102 in the special group. Upon receiving the EMM data 108, the data selecting apparatus 104 compares the information stored in the first field 110 to the first parameter 130, the second parameter 131, and the fourth parameters 133 and 134 as already described with reference to tigure 7. Since the

33
special group number "0C02h" is set in the first field
110, the "OOO2h." matches the fourth parameter 134 of the receiver 102, so that the EMM data 108 passes through
the fourth detecting circuit 139 to the output unit, 10, which outputs the EMM data 108.
As thus described, broadcasting for the special group, namely, a receiving group comprising receivers under a contract of special service can be provided. On the other hand, in a case where another number is set in a storage position of the special group number, since it is different, from the fourth parameter 134, the EMM data 108 will net be output from the output unit 107.
Although the aforementioned four cases have been described as being separate ones, both the broadcasting for all receivers and the broadcasting for the special group become possible provided that both "OOOlh" and "0Q02h" are set in the receiver 102 as the fourth parameters. Furthermore, the numbers or the fourth parameters and the fourth detecting circuits may be increased to set and detect plural kinds of special groups, thereby broadcasting for plural special groups can be provided.
Besides, the first field 110 or the receiver indivi dual number is illustrative and not restrictive. In addition, although the EMM data 108 is transmitted in

a section data format in the above description, a data selecting apparatus which selects data having another format nay be employed. Yet in addition, although the data transmission in digital broadcasting according to MPEG has beer, described, the data transmission is not restricted thereto, and is applicable to a case where data comprising plural fields is selected.
As should be appreciated from the foregoing description, in accordance with the preferred embodiment of the present invention, in digital broadcasting in which various types or data is multiplexed and transmitted, the following data transmission is realized. (1) Data is transmitted to a specified receiver. (2) Data is transmitted to a specified group{receivers are grouped by their individual numbers). (3) Data is transmitted to all receivers simultaneously. (4) Data is transmitted to every receiver in a special group (receivers are grouped on a service basis). As a consequence, destination is specified flexibly, whereby maximum efficiency in use of transmission bandwidth is achieved while significantly reducing the frequency at which the same data is transmitted, as compared with a case where data is transmitted to one receiver.
Furthermore, in accordance with the preferred embodiment on the present invention, since a receiver

35
individual, number for identifying a destination receiver of EMM data is determined by group specifying information indicating a receiving group to which the destination receiver belongs, and in-group identifying information for identifying the receiver in the receiving group, and the in-group identifying information is included in the group destination directing information of the EMM data, it is possible to make a decision on the group destination directing information, and simultaneously on whether there is a match in the in-group identifying number. Therefore, when the EMM data is selected by the data selecting circuit, a match in the group specifying information is detected by a" single detecting circuit (third detecting circuit) irrespective of group destination or individual receiver destination, resulting in reduced processing amount, for deriding whether to receive the EMM data. As a consequence, it is possible to select EMM data with a small scale circuit.

36
WE CLAIM
X. A digital communication system comprising;
A transmitter for sequentially transmitting predetermined format data; and A plurality of receivers each including a data selecting apparatus for selecting required data from received data group and outputting selected data, wherein
said transmitter transmits data to said receivers in one of a first transmission mode in which group destination assignment information indicating whether the data is transmitted to a specified receiver of said plurality of receivers, to a group consisting of specified plural receivers, or to all receivers, group specifying information for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information for identifying a receiver to which the data is to be transmitted, in a receiving group which is specified by the group specifying information, are included in the data, and the group destination assignment information in said First transmission mode indicates that the data is transmitted to a specified receiver of said plurality of receivers, a second transmission mode in which the group destination assignment information and the group specifying information are included in the data, and the group destination assignment information in said second transmission mode indicates that the data is transmitted to a group consisting of specified plural receivers, and
a third transmission mode in which the group destination assignment information is included in the data, and the group destination assignment information in said third transmission mode indicates that the data is transmitted to all receivers.
2. The digital communication system as claimed in claim 1, wherein
said transmitter includes data structuring means for structuring data to be
transmitted, and
said data selecting apparatus includes:
Parameter storage means for prestoring plural parameters which are to be

compared to the group destination assignment information, the in-group identification information, and the group specifying information; correspondence pattern detecting means for comparing the information stored in the data to the parameters, respectively, to detect correspondence patterns; and
output means for selecting the required data according to the correspondence patterns detected by the correspondence pattern detecting means and outputting the selected data.
3. The digital communication system as claimed in claim 2, wherein
said group destination assignment information includes a group destination number indicating that the second transmission mode is used to be transmitted when the data to be transmitted is destined for the group,
said group destination assignment information includes a specified receiver destination number indicating that the first transmission mode is used to be transmitted when the data to be transmitted is destined for the specified receiver,
said parameter storage means prestores a first parameter to be compared to the group destination number, a second parameter to be compared to the specified receiver destination number and the in-group identification information, and a third parameter to be compared to the group specifying information,
said correspondence pattern detecting means:
detects transmission being performed in the first transmission mode and indicating that the transmitted in-group identification information is a data to be received, when the specified receiver destination number and the in-group identification information match the second parameter; judges that the first correspondence pattern is detected, when the group specifying information matches the third parameter in the first transmission mode;

detects transmission being performed in the second transmission mode, when the group destination number matches the first parameter; and judges that the second correspondence pattern is detected, when the -group specifying information matches the third parameter, and said output means selects the required data according to one of the first and second correspondence patterns and outputs the selected data.
4. The digital communication system as claimed in claim 3, wherein
said group destination assignment information includes all specifying
numbers indicating that the third transmission mode is used to be transmitted when the data to be transmitted is destined for the all receivers,
said parameter storage means prestores a fourth parameter to be compared to the all specifying numbers,
said correspondence pattern detecting means detects transmitted being performed in the third transmission mode and judges that being a data to be received, when detecting a third correspondence pattern that the number for specifying al! receivers matches the fourth parameter in the third transmission mode, and
said output means selects the required data according to the third correspondence pattern and outputs the selected data.
5. The digital communication system as claimed in claim 4, wherein
said group destination assignment information includes a special group
number when the data to be transmitted is destined for all receivers which belong to a special group, when the data to be transmitted is destined for al! receivers which belong to the special group,
said parameter storage means prestores a fourth parameter to be compared to the special group number,
said correspondence pattern detecting means detects transmission being performed in the third transmission mode and judges that the special group number is a data to be received, when detecting a fourth correspondence

39
pattern that the special group number matches the fourth parameter in the third transmission mode, and
said output means selects the required data according to the fourth correspondence pattern and outputs the selected data.
6. A transmitter which is used in a digital communication system wherein
data is structured to be in a predetermined format and is transmitted to
a plurality of receivers, said transmitter including:
data structuring means for structuring data to be transmitted in one of a first data transmission mode in which group destination assignment information indicating whether the data is transmitted to a specified receiver of said plurality of receivers, to a group consisting of specified plural receivers, or to ail receivers, group specifying information for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information for identifying a receiver to which the data is to be transmitted, in a receiving group which is specified by the group specifying information, are included in the data, and the group destination assignment information in said first transmission mode indicates that the data is transmitted to a specified receiver of said plurality of recievers,
a second data transmission mode in which the group destination assignment information and the group specifying information are included in the data, and the group destination assignment information in said second transmission mode indicates that the data is transmitted to a group consisting of specified plural receivers, and
a third data transmission mode in which the group destination assignment information is included in the data, and the group destination assignment information in said second transmission mode indicates that the data is transmitted to all receivers.
7. The transmitter as claimed in claim 6, wherein
said group destination assignment information in the first transmission
mode includes a specified receiver destination number indicating that the data to

be transmitted is destined for a specified receiver when the data to be transmitted is destined for the specified receiver.
8. The transmitter as claimed in claim 6, wherein
said group destination assignment information in the second transmission mode includes a group destination number indicating that the data to be transmitted is destined for a group, when the data to be transmitted is destined for the group.
9. The transmitter as claimed in claim 6, wherein
said group destination assignment information in the third transmission mode includes ail specifying numbers indicating that the data to be transmitted is destined for all receivers, when the data to be transmitted is destined for ail receivers,
10. The transmitter as claimed in claim 6, wherein
said group destination assignment information in the third transmission mode includes a special group number indicating that the data to be transmitted is destined for all receivers which belong to a special group, when the data to be transmitted is destined for the all receivers which belong to the special group.
11. A data selecting apparatus built in a receiver in digital communication
system, which is supplied with predetermined format data as inputs and
selects required data from input data group and outputs selected data,
said apparatus comprising.
Parameter storage means for prsstoring plural parameters which are to be compared to group destination assignment information in trie data indiiit in a receiver in digital communication system, which is supplied with predetermined format data as inputs and selects required data from input data group and outputs selected data, said apparatus comprising,
parameter storage means for prestoring plural parameters which are to be compared to group destination assignment information in the data

indicating whether the data to be transmitted is transmitted to a specified receiver of said plurality of receivers/ to a group consisting of specified plural receivers, or to al! receivers, group specifying information in the data for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information in the data for identifying a receiver to which the data is to be transmitted, in a receiving group which is specified by the group specifying information ; correspondence pattern detecting means for comparing the information stored in the data to the parameters, respectively, to detect correspondence patterns; and
output means for selecting the required data according to the correspondence patterns detected by the correspondence pattern detecting means and outputting the selected data.
12. The data selecting apparatus as claimed in claim 13, wherein
said group destination assignment information includes a group destination number indicating that the second transmission mode is used to be transmitted when the data to be transmitted is destined for the group,
said group destination assignment information includes a specified receiver destination number indicating that the first transmission mode is used to be transmitted when the data to be transmitted is destined for the specified receiver,
said parameter storage means prestores a first parameter to be compared to the group destination number, a second parameter to be compared to the specified receiver destination number and the in-group identification information, and a third parameter to be compared to the group specifying information,.
said correspondence pattern detecting means:
detects transmission being performed in the first transmission mode and indicating that the transmitted in-group identification information is a data to be received, when the specified receiver destination number and the in-group identification information match the second parameter;

judges that the first correspondence pattern is detected, when the group specifying information matches the third parameter;
detects transmission being performed in the second transmission mode, when the group destination number matches the first parameter; and
judges that the second correspondence pattern is detected, when the group specifying information matches the thirds parameter, and
said output means selects the required data according to one of the first and second correspondence patterns and outputs the selected data.
13. The data selecting apparatus as claimed in claim 12, wherein
said group destination assignment information includes all specifying
numbers indicating that the third transmission mode used to be
transmitted, when the data to be transmitted is destined for the a!!
receivers,
said parameter storage means prestores a fourth parameter to be
compared to the all specifying numbers,
said correspondence pattern detecting means detects transmission
being performed in the third transmission mode and judges that being 3
data to be received, when detecting a third correspondence pattern that
the number for specifying at receivers matches the fourth parameter,
and
said output means selects the required data according to the third
correspondence pattern and outputs the selected data.
14, The data selecting apparatus as claimed in claim 12, wherein
said group destination assignment information includes a special group number indicating that the data to be transmitted is destined for a!! receivers which belongs to a special group, when the data to be transmitted is destined for the all receivers which belong to the special group,

43
said parameter storage means prestores a fourth parameter to be
compared to the special group number,
said correspondence pattern detecting means detects transmission
being performed in the third transmission mode and judges that the
special group number is a data to be received, when detecting a fourth
correspondence pattern that the special group number matches the
fourth parameter, and
said output means selects the required data according to the fourth
correspondence pattern and outputs the selected data.
15, A digital communication system comprising:
a transmitter for sequentially transmitting predetermined format data;
and
A plurality of receivers each including a data selecting apparatus for
selecting required data from received data group and outputting
selected data, wherein
said transmitter transmits data to said receivers in one of the first
transmission mode in which group destination assignment information
directing which transmission mode is used among the first transmission
mode, the second transmission mode, and the third transmission mode,
the second transmission mode, and the third transmission mode, to
transmit the data, group specifying information for specifying a
receiving group of receiving groups to which the data is to be
transmitted, and in-group identification information for identifying a
receiver in an arbitrary receiving group to which the data is to be
transmitted, are included in the data,
the second transmission mode in which the group destination
assignment information and the group specifying information are
included in the data, and
the third transmission mode in which the group destination assignment
information is included in the data.

16. A transmitter which is used in a digital communication system
wherein data is structured to be in a predetermined format and is transmitted to a plurality of receivers, said transmitter including: data structuring means for structuring data to be transmitted in one of a first data transmission mode in which group destination assignment information directing which transmission mode is used among the first transmission mode, the second transmission mode, and the third transmission mode to transmit the data, group specifying information for specifying a receiving group of receiving groups to which the data is to be transmitted, and in-group identification information for identifying a receiver in an arbitrary receiving group which the data is to be transmitted, are included in the data,
the second data transmission mode in which the group destination assignment information and the group specifying information are included in the data, and
the third data transmission mode in which the group destination assignment information is included in the data.

A digital communication system comprises a
transmitter for sequentially transmitting prescribed format data; and plural receivers each comprising a data selecting apparatus for selecting required data from received data group and outputting selected data; the transmitter transmitting data to said receivers in one of a first transmitting mode in which group destination directing information indicating that the data is transmitted to a receiving group consisting of prescribed receivers of the plural receivers, group specifying information for specifying a receiving group of receiving groups to which the data is transmitted, and in-group identifying information for specifying a receiver in an arbitrary receiving group to which the data is transmitted, are included in the data, a second transmitting mode in which the group destination directing information and the group specifying information are included in the data; and a third transmitting mode in which the group destination directing information is included in the data.

Documents:

00529-cal-1998 abstract.pdf

00529-cal-1998 claims.pdf

00529-cal-1998 correspondence.pdf

00529-cal-1998 description(complete).pdf

00529-cal-1998 drawings.pdf

00529-cal-1998 form-1.pdf

00529-cal-1998 form-2.pdf

00529-cal-1998 form-3.pdf

00529-cal-1998 form-5.pdf

00529-cal-1998 pa.pdf

00529-cal-1998 priority document.pdf

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Patent Number

194447

Indian Patent Application Number

529/CAL/1998

PG Journal Number

30/2009

Publication Date

24-Jul-2009

Grant Date

22-Jul-2005

Date of Filing

27-Mar-1998

Name of Patentee

MATSUSHITA ELECTRIC INDUSTRIAL CO.LTD

Applicant Address

1006,OAZA KADOMA,KADOMA-SHI,OSAKA 571-8501

Inventors:

#	Inventor's Name	Inventor's Address
1	NORIHIKO MIZOBATA	OSAKAFU HABIKINOSHI HABIKIGAOKANISHI 3-6-20,583-0865,

PCT International Classification Number

H04L 27/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	9-082526	1997-04-01	Japan