JP2005073238A - Retransmission device and receiving device for digital broadcasting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retransmission device and a receiving device for a digital broadcasting system, in which the retransmission device performs retransmission of terrestrial digital television broadcasting based on a trans-modulation method, and the receiving device performs a resetting of a reception setting or performs an automatic retransmission without subscriber's time and effort, even when the retransmission is newly started when update of retransmission frequency etc. are performed. <P>SOLUTION: The retransmission device 101 comprises a rewriting unit 114 for updating the version number of SDDT for scan notification by rewriting the SDTT for scan notification included in the terrestrial digital television broadcasting into content for notifying changes in retransmission frequency etc. The receiving device 104 comprises an exploring unit 146 for exploring receivable retransmission frequency when the version number of the SDTT for scan notification is updated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a retransmission device that retransmits digital terrestrial television broadcasting or the like as digital cable television broadcast or the like, and a reception device that receives terrestrial digital television broadcast or the like retransmitted as digital cable television broadcast or the like, In particular, the present invention relates to a retransmission apparatus that notifies a change in the retransmission frequency of a digital broadcast composed of a plurality of networks, and a reception apparatus that receives the notification and resets reception settings.

  Conventionally, in cable broadcasting such as cable television broadcasting, wireless broadcasting such as terrestrial broadcasting, BS broadcasting, CS broadcasting, etc. are collectively received and retransmitted from the viewpoint of the number of provided channels and subscribers. Has been done. Furthermore, in recent years, for example, digital broadcasting in which these wireless broadcasts are digitized and a download service or the like is added has been started, such as CS digital broadcasting and BS digital broadcasting. Along with this, cable broadcasting has also been digitized in accordance with these digital broadcasting. Also, it is desired that terrestrial digital broadcasting is retransmitted while being digitized.

  Here, re-transmission of digital broadcasting will be described. There are the following two methods for retransmitting digital broadcasting. One is a pass-through method, and the other is a trans-modulation method.

  The pass-through method is a method of transmitting the received broadcast wave without changing the modulation method. The digital broadcast retransmitted by this method is viewed via a receiving device installed in the subscriber's home, for example, a digital tuner, a digital tuner built-in television (hereinafter referred to as a digital tuner or the like). Since the modulation method is not changed, a receiving apparatus corresponding to digital broadcasting similar to the case of direct reception can be used.

  The transmodulation method is a method of retransmitting after converting the modulation method of each digital broadcast into a modulation method suitable for cable broadcasting. The digital broadcast retransmitted by this method is viewed via a receiving device installed at the subscriber's house, for example, a set top box (hereinafter referred to as STB) for wired broadcasting. An STB for cable broadcasting is required to convert the modulation method, but since it is transmitted in the same modulation method, including retransmission of independent broadcasts and other digital broadcasts, digital cable television with a single receiver Various services provided by John Broadcasting Station can be received.

  In the retransmission of terrestrial digital broadcasting, both the pass-through method and the transmodulation method are put into practical use. The pass-through method allows viewing by connecting a digital tuner or the like similar to the case of direct reception, and does not require an STB for cable broadcasting. For this reason, the system is suitable for a digital cable television broadcasting station that mainly performs only retransmission of terrestrial digital broadcasting. On the other hand, the trans-modulation method can receive various services provided by digital cable television broadcasting stations such as BS digital broadcasting and original broadcasting with a single STB. For this reason, it is a system suitable for digital cable television broadcasting stations that mainly perform independent broadcasting. Note that even if a digital cable television broadcasting station that performs independent broadcasting has a sufficient bandwidth, it considers the convenience of subscribers who view only digital terrestrial broadcasting, and the transmodulation method and pass-through method. In some cases, both systems are used.

  Now, terrestrial digital broadcasting differs from digital broadcasting that can receive the same national broadcasting such as BS digital broadcasting, for example, and the number of channels that can be received differs depending on the receiving area. When a network configuration called MFN (Multi Frequency Network) is used, even the same digital broadcast may be transmitted at different frequencies depending on the reception area. In addition, since the terrestrial digital broadcast is initially broadcast in parallel with the analog broadcast, the broadcast area is started in a limited manner. Then, the frequency of analog broadcasting is changed to another frequency to open a channel used for digital broadcasting (hereinafter referred to as “anaana-analog conversion”), while gradually observing the influence on analog broadcasting, gradually increasing the broadcasting area, Work to increase the number etc. is performed. Furthermore, at the end of analog broadcasting, work for changing the frequency used for digital broadcasting (hereinafter referred to as repacking) will be performed for the purpose of optimal network configuration.

  That is, in terrestrial digital broadcasting, the frequency that can be received differs depending on the area where the viewer resides. Furthermore, the number of channels that can be received, the number of services, etc. gradually increase from the start of broadcasting, and it is necessary to change the reception settings each time. And since it is necessary to change the reception frequency all together at the time of repacking, a method of automatically following the reception setting, frequency change, etc. without the effort of the viewer is essential.

  On the other hand, a method of automatically following reception setting, frequency change, etc. using an engineering download service that updates software of a receiving device using digital broadcasting is described in [Reference 1] and [Reference 2]. It is stipulated in.

[Reference 1] ARIB TR-B14-1 "Technical data for terrestrial digital television broadcast operation" first volume [Reference 2] ARIB TR-B14-2 "Second technical volume for" terrestrial digital television broadcast operation specification "[Reference] 3] ARIB TR-B14-3 “Terrestrial digital television broadcast operation regulation technical data” third volume Specifically, in terrestrial digital broadcasting, a list of frequencies transmitted from local broadcasting stations and change information (hereinafter referred to as frequency (Referred to as list / change information). Also, download notification information (hereinafter referred to as SDTT) is transmitted to all digital broadcasting.

  Here, the version number, transmission channel, and transmission time zone of the download content are set in the SDTT. Furthermore, in the case of the frequency list / change information SDTT, information related to the work period during which repacking is performed is also set. And (a) when a new broadcast station starts broadcasting in each region, (b) when an existing broadcast station changes the frequency, (c) when the broadcast output is changed and the reception area is expanded, etc. The content of the frequency list / change information is updated based on the information, and the version number described in the SDTT is updated.

  Accordingly, the version number described in the SDTT is updated in the receiving device that directly receives the terrestrial digital broadcast and the receiving device that receives the terrestrial digital broadcast retransmitted by the pass-through method (for example, a digital tuner). If the frequency list / change information is downloaded, the frequency list / change information is downloaded, and the downloaded frequency list / change information is stored in the nonvolatile memory. If reception is not possible at the frequency set for reception, refer to the frequency list / change information stored in the non-volatile memory, and if there is a possibility that the frequency set for reception has been changed. Try to receive at a new frequency. As a result, when the reception is successful at the new frequency, the reception-set frequency is automatically updated or the viewer is notified of the resetting. In addition, when the frequency and work period at which a new broadcasting station starts broadcasting are set in the frequency list / change information, it tries to receive at the frequency set in the frequency list / update information in the standby state. . If reception is successful at the frequencies listed in the frequency list / update information, a new broadcasting station is automatically added to the reception setting, or a reset is notified to the viewer.

  By the method as described above, a receiving device (for example, a digital tuner) that directly receives digital terrestrial broadcasting realizes resetting or automatic updating of reception settings without the effort of the viewer.

  Note that the pass-through method includes a frequency conversion pass-through method in which the frequency is converted and retransmitted instead of being retransmitted at the same frequency as the frequency transmitted from the broadcasting station. In the case of the frequency conversion pass-through method, it is not possible to receive at the frequencies set in the frequency list / change information. Along with this, since the above method cannot automatically update the reception setting, in the following cases (a) and (b), the reception is performed without using the frequencies described in the frequency list / change information. A method of scanning all possible frequencies to obtain a new frequency is defined (for example, see Non-Patent Document 1).

(A) The frequency may be changed with reference to the frequency list / change information.
(B) When there is a frequency for which reception is not set.
ARIB TR-B14-1 “Technical data for terrestrial digital television broadcasting operation regulation” first volume (1.4 edition), pages 1-7, 2-41, Japan Radio Industry Association, June 2003 5th revision

  However, in the above method, when the digital cable television broadcasting station changes the retransmission frequency, the content of the frequency list / change information and the version number described in the SDTT are not updated. (Hereinafter also referred to as STB) cannot determine that there is a possibility that the frequency has been changed by referring to the frequency list / change information. Therefore, when the retransmission frequency is changed at the digital cable television broadcasting station, there is a problem that the STB cannot automatically update the reception setting or notify the resetting.

  Also, when a new broadcast station starts broadcasting, the transmodulation method requires an additional re-transmission device in the digital cable television broadcast station. Retransmission cannot always be started during the work period. For this reason, there is a problem that the STB cannot automatically add a new broadcasting station to the reception setting or notify the resetting.

  The present invention has been made in view of the above problems, and in a retransmission apparatus that retransmits a digital terrestrial television broadcast based on a transmodulation scheme, when a retransmission frequency is changed, or newly To provide a retransmission apparatus and a reception apparatus for a digital broadcasting system in which a reception apparatus resets a reception setting or automatically resets it without requiring the effort of a subscriber even when retransmission is started. With the goal.

<Solution 1>
In order to achieve the above object, a retransmitting apparatus according to the present invention is a retransmitting apparatus that remodulates and retransmits a digital broadcast modulated by a first modulation scheme and transmitted by a second modulation scheme. Thus, the information for notifying the transmission of the first frequency information related to the transmission frequency of the digital broadcast that is modulated and transmitted by the first modulation method is used as the first notification information, and is remodulated by the second modulation method. The information for notifying the change of the transmission frequency of the digital broadcast to be retransmitted is the second notice information, and the first notice information included in the digital broadcast modulated and transmitted by the first modulation method is the second notice information. A rewriting means for rewriting the notification information is provided.

<Solution 2>
Further, the transmission frequency of the digital broadcast that is re-modulated and re-transmitted by the second modulation method is used as the retransmission frequency, and the second notification information includes a version number that is updated every time the retransmission frequency is changed, The retransmission apparatus further includes holding means for holding second frequency information related to a retransmission frequency, and the rewriting means further includes (a) the second frequency information is newly held in the holding means. (B) when the second frequency information held in the holding means is updated, or (c) when the second frequency information held in the holding means is deleted, The version number may be updated.

<Solution 3>
Alternatively, the first notification information includes first channel information related to a transmission channel of the first frequency information, and the second notification information is transmitted including the first frequency information in digital broadcasting. The rewriting means may further rewrite the first channel information to the second channel information.

<Solution 4>
Alternatively, the first notification information includes first time information related to a transmission start time of the first frequency information, and the second notification information includes an operation of updating a transmission frequency of a digital broadcast to be retransmitted. The rewriting means may further rewrite the first time information into the second time information, including second time information indicating a time to end.

<Solution 5>
Alternatively, the rewriting means may further perform (b) modulation with the first modulation method, when (a) update work of the transmission frequency of the digital broadcast to be remodulated and retransmitted with the second modulation method is not scheduled. The first digital broadcast included in the digital broadcast transmitted after being modulated by the first modulation method in any case where all of the transmitted digital broadcasts are re-modulated by the second modulation method and not retransmitted. The notification information may be deleted.

<Solution 6>
Alternatively, the rewriting means may further include, in the second notification information, an identifier assigned to the digital broadcast that stops transmission among the digital broadcasts that are remodulated and retransmitted by the second modulation method. .

<Solution 7>
Alternatively, the rewriting unit may further include an identifier assigned to an installation location of the retransmission apparatus in the second notification information.

<Solution 8>
Alternatively, the first modulation scheme may be OFDM (Orthogonal Frequency Division Multiplexing), and the second modulation scheme may be 64 QAM (64 Quadrature Amplitude Modulation).

<Solution 9>
Alternatively, the first frequency information is a list of transmission frequencies of digital broadcasting that is modulated by the first modulation method and transmitted, and a frequency list / change information that indicates change information when the transmission frequency is changed. In addition, the first notification information may be notification information for notifying transmission of the frequency list / change information.

<Solution 10>
In order to achieve the above object, a receiving apparatus according to the present invention is a receiving apparatus that receives a digital broadcast that has been remodulated and retransmitted using a predetermined modulation scheme, and is retransmitted after being modulated using a predetermined modulation scheme. Transmission information that can be received if the notification information included in the digital broadcast that has been modulated and transmitted by a predetermined modulation method is updated with the information that is notified of a change in the transmission frequency of the digital broadcast being performed as notification information. An exploration means for exploring is provided.

<Solution 11>
Further, the transmission frequency of the digital broadcast that is modulated and retransmitted by a predetermined modulation method is used as a retransmission frequency, and the notification information includes a version number that is updated every time the retransmission frequency is changed. In addition, a first holding unit that holds the notification information is provided, and the search unit further performs modulation using a predetermined modulation method with reference to version information included in the notification information held in the first holding unit. If the version number of the notification information included in the digital broadcast to be retransmitted is updated, the receivable transmission frequency may be searched.

<Solution means 12>
Alternatively, the notification information includes time information indicating a time at which the update operation of the digital broadcast frequency to be retransmitted ends, and the searching means further searches after the time specified by the time information. Also good.

<Solution 13>
Alternatively, the reception device further includes reception setting holding means for holding reception setting information in which a receivable transmission frequency and a channel number are associated with each other, and the search unit further includes the reception setting information as a result of the search. When a transmission frequency that is not registered in is found, information related to the discovered transmission frequency may be registered in the reception setting information.

<Solution 14>
Alternatively, the reception device further includes reception setting holding means for holding reception setting information in which a receivable transmission frequency and a channel number are associated with each other, and the search unit further includes the reception setting information as a result of the search. In the case where the transmission frequency registered in is not found, information related to the transmission frequency that was not found may be deleted from the reception setting information.

<Solution 15>
Alternatively, the receiving device further includes reception setting holding means for holding reception setting information in which a receivable transmission frequency and a channel number are associated with each other, and the searching means is further remodulated with a predetermined modulation method. If the identifier assigned to the digital broadcast whose transmission is to be stopped among the digital broadcasts to be retransmitted is included in the notification information, the information on the transmission frequency for receiving the digital broadcast specified by the identifier is It may be deleted from the reception setting information.

<Solution 16>
Alternatively, the notification information may include an identifier assigned to each installation location of a retransmission apparatus that retransmits the digital broadcast, and the search unit may manage the notification information for each identifier.

<Solution 17>
Alternatively, the predetermined modulation scheme may be 64QAM.

<Solution 18>
Alternatively, the list of transmission frequencies of the digital broadcast to be retransmitted and the change information when the transmission frequency is changed are used as the frequency list / change information, and the notification information is transmitted by including the frequency list / change information in the digital broadcast. It may be notification information including channel information indicating that it does not.

  The present invention can be realized not only as a retransmission apparatus, but also a method for controlling the retransmission apparatus, a program for causing a general hardware system such as a computer or an embedded apparatus to execute the method, and the program Needless to say, it can be realized as a recording medium on which is recorded.

  The present invention can be realized not only as a receiving device, but also a method for controlling the receiving device, a program for causing a general hardware system such as a computer or an embedded device to execute the method, and the program recorded therein. Needless to say, it can be realized as a recording medium.

  Needless to say, the present invention can also be realized as a digital broadcast system having a retransmission apparatus and a reception apparatus. In addition to being realized as a digital broadcast system, a method for controlling the digital broadcast system, a program for causing a general hardware system such as a plurality of computers and embedded devices to execute the method, and a program recorded therein Needless to say, it can be realized as a recording medium.

  According to the retransmitting device, the receiving device, and the digital broadcasting system having these according to the present invention, when digital broadcasting is retransmitted from the retransmitting device by the transmodulation method, (a) the transmission frequency for retransmitting Is changed on the digital cable television broadcasting station side, (b) Even if re-transmission is started from a newly opened broadcasting station, the reception setting of the receiving device is re-established without taking the trouble of the subscriber. Can be set and automatically updated.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.
<Overview>
The digital cable television broadcasting system (hereinafter referred to as CATV system) in the first embodiment of the present invention uses frequency notification / change information download notification information for digital terrestrial television broadcasting as scan notification information of the present invention. rewrite.

  The scan notification information is transmitted by a software download trigger table (SDTT) transmitted in a section format, like the frequency list / change information and the download notification information of other download contents.

<CATV system>
FIG. 1 is a schematic diagram showing a configuration of a CATV system according to Embodiment 1 of the present invention.
As shown in the figure, the CATV system 100 mixes the terrestrial digital television broadcast retransmitted from the retransmission apparatus 101 corresponding to each terrestrial digital television broadcast in the mixing unit 102, and passes through the CATV network 103. To the receiving device 104 installed in the subscriber's home.

  Specifically, the CATV system 100 retransmits digital terrestrial television broadcasting based on the transmodulation method. Since the modulation frequency is changed and the transmission frequency is also changed, the retransmission apparatus 101 scans the SDTT for downloading the frequency list / change information for digital terrestrial television broadcasting in accordance with the circumstances of digital cable television broadcasting. The notification SDTT is rewritten and sent to the receiving device 104.

  Along with this, when receiving the SDTT for scan notification for digital cable television broadcasting, the receiving device 104 regards it as one of the following cases (a) to (f) and searches for the reception frequency (hereinafter referred to as scan). Can be implemented).

(A) A digital terrestrial television broadcast is newly retransmitted.
(B) A new terrestrial digital television broadcast was retransmitted.
(C) The retransmission frequency of terrestrial digital television broadcasting is changed and retransmitted.
(D) The re-transmission frequency of terrestrial digital television broadcasting was changed and re-transmission was performed.
(E) Digital terrestrial television broadcasting is not retransmitted.
(F) Terrestrial digital television broadcasting is no longer retransmitted.

“Retransmission frequency” refers to a transmission frequency when digital terrestrial television broadcast is retransmitted from the retransmission apparatus 101 to the reception apparatus 104 as digital cable television broadcast.
The “reception frequency” refers to a transmission frequency of digital cable television broadcast that can be received by the receiving device 104.

<Retransmission device>
FIG. 2 is a functional block diagram showing a configuration of the retransmission apparatus according to the first embodiment.
As shown in the figure, the retransmitting apparatus 101 retransmits one terrestrial digital television broadcast with 64QAM digital modulation. When changing the retransmission frequency or the like, a scan notification SDTT for digital cable television broadcasting is transmitted.

  Here, as an example, the retransmission apparatus 101 includes a scan notification SDTT holding unit 111, a time measuring unit 112, a demodulation unit 113, a rewriting unit 114, a multiplexing unit 115, a modulation unit 116, and a retransmission frequency information holding unit 117. Composed.

The scan notification SDTT holding unit 111 holds the same scan notification SDTT sent for digital cable television broadcasting.
The time measuring unit 112 measures and notifies the time.

The demodulator 113 demodulates the terrestrial digital television broadcast received via the antenna into a TS.
The rewrite unit 114 rewrites the frequency notification / change information download notification SDTT for digital terrestrial television broadcasting into the scan notification SDTT.

  The digital terrestrial television broadcast is modulated by OFDM (Orthogonal Frequency Division Multiplexing), and the digital cable television broadcast is modulated by 64 QAM (64 Quadrature Amplitude Modulation). For example, the frequency list / change information included in the terrestrial digital television broadcast is invalid for the receiving apparatus 104 that receives the digital broadcast with 64QAM because the transmission frequency set in the frequency list / change information is based on OFDM. Information.

  On the other hand, the rewriting unit 114 does not transmit the frequency list / change information transmission channel included in the digital terrestrial television broadcast and the frequency list / change information included in the digital cable television broadcast. Rewrite the value to indicate. In addition, the transmission start time of the frequency list / change information is rewritten to the time when the update operation of the re-transmission frequency of the digital cable television broadcast is completed.

  In addition, when the next plans (a) and (b) are scheduled, the rewriting unit 114 updates the version number included in the scan notification SDTT transmitted for digital cable television broadcasting.

(A) Retransmission frequency change or the like in any of a plurality of retransmission apparatuses (b) Retransmission of terrestrial digital television broadcasts transmitted from a newly opened broadcasting station The multiplexing unit 115 performs terrestrial digital television broadcasts Are included in the TS for multiplexing to fill the speed difference between the transmission speed of the digital cable television and the transmission speed of the digital cable television broadcast. Further, multiplexing is performed based on the multiple TS transmission method as necessary. Further, a network information table (hereinafter referred to as NIT) included in the signal of terrestrial digital television broadcast is rewritten for digital cable television broadcast.

  The modulation unit 116 modulates the signal multiplexed by the multiplexing unit 113 into a signal based on 64 QAM (64 Quadrature Amplitude Modulation).

The retransmission frequency information holding unit 117 holds information on the frequency retransmitted from the digital cable television broadcasting station.
Although not shown in the figure, the retransmission frequency information holding unit 117 is a storage area allocated to a non-volatile memory provided in the retransmission apparatus 101 by a control program for controlling the retransmission apparatus 101. .

  It is desirable that the retransmitting apparatus 101 sends out the SDTT for scan notification before the date and time when the work associated with the change of the retransmitting frequency is performed. Further, the scan notification SDTT may be transmitted only during a period during which the retransmission frequency is changed, and the transmission may be stopped when the change work is completed, but an STB that has not received the scan notification SDTT by the change date and time may be used. In order to save, the scan notification SDTT may be continuously sent even after the scan date and time. However, in this case, when work associated with the next change in the retransmission frequency occurs, the scan notification SDTT with a new date and time is switched and transmitted. In addition, when the change work is not completed by the date and time designated in the scan notification SDTT, the re-transmission apparatus 101 sets a new work date and sends out the scan notification SDTT in which the version number is updated. It is good.

<Receiving device>
FIG. 3 is a functional block diagram showing a configuration of the receiving apparatus in the first embodiment.
The receiving device 104 is a set top box (hereinafter referred to as STB) dedicated to digital terrestrial television broadcasting retransmitted from the retransmission device 101 via the CATV network 103, that is, digital cable television broadcasting that receives a transmodulation signal. Is called). Then, the received transmodulation signal is demodulated into a TS and reproduced.

  Here, as an example, the reception device 104 includes a reception setting holding unit 141, a reception unit 142, a demodulation unit 143, a reproduction unit 144, a detection unit 145, a search unit 146, a scan notification SDTT holding unit 147, and a time measuring unit 148. Composed.

The reception setting holding unit 141 holds information related to the reception frequency set as a reception channel (hereinafter referred to as reception setting information).
The receiving unit 142 receives the terrestrial digital television broadcast specified by the reception setting held in the reception setting holding unit 141 among the terrestrial digital television broadcasts retransmitted via the CATV network 103.

The demodulator 143 demodulates the transmodulation signal received by the receiver 142 into a TS.
The reproduction unit 144 reproduces the TS demodulated by the demodulation unit 143. For example, a TS decoder or the like decomposes the TS into video / audio / data and displays the decomposed video / audio / data on the television screen.

  The detection unit 145 detects the SDTT included in the TS signal demodulated by the demodulation unit 143. If the detected SDTT is a scan notification SDTT, the detected SDTT is passed to the search unit 146.

  The search unit 146 receives the scan notification SDTT from the detection unit, and stores the received scan notification SDTT in the scan notification SDTT holding unit 147. In the following cases (a) and (b), the reception frequency is searched after the scan start possible time (start_time) included in the scan notification SDTT. If a new reception frequency is found as a result of the search, the reception setting held in the reception setting holding unit 141 is automatically reset as a new channel, or the subscriber is subscribed after notifying the subscriber. Reset according to the instructions of the operator.

(A) When a scan notification SDTT is newly detected by the detection unit 145 (b) When a version number (version_number) included in the scan notification SDTT is updated The scan notification SDTT holding unit 147 The scan notification SDTT sent for television broadcasting is held.

The timer unit 148 measures and notifies the time.
Although not shown in the figure, each of the reception setting holding unit 141 and the scan notification SDTT holding unit 147 is stored in a nonvolatile memory provided in the receiving device 104 by a control program for controlling the receiving device 104. This is the allocated storage area.

<Description of each field of SDTT for scan notification>
FIG. 4 is a diagram showing a table related to the data structure of SDTT.
As shown in the figure, the table 150 includes columns 151 to 153.

A column 151 shows the data structure of SDTT.
A column 152 indicates the number of bits allocated to the data field of SDTT.
A column 153 shows remarks related to the data field of SDTT.

The SDTT is composed of fields 151a to 151w.
The field 151a (table_id) is an 8-bit data field in which “0xC3” is set. “0xC3” is an identifier indicating SDTT.

A field 151b (section_syntax_indicator) is a 1-bit data field in which “1” is set.
A field 151c (section_length) is a 12-bit data field in which the section length of SDTT is set. The section length is 4093 or less.

  The field 151d (table_id_ext) is a 16-bit data field in which the value “0xFFF8” of model_id and maker_id is set. Note that maker_id is set in the upper 8 bits, and model_id is set in the lower 8 bits. In the case of frequency list / change information download notification and scan notification, “0xFFF8” is set.

  A field 151e (version_number) is a 5-bit data field in which a version number is set. When there is a change in the information in the subtable, 1 is added to the field. When the value becomes 31, the value returns to 0.

  A field 151f (current_next_indicator) is a 1-bit data field in which “1” is set. It is used based on the MPEG standard.

A field 151g (section_number) is an 8-bit data field in which a section number is set.
A field 151h (last_section_number) is an 8-bit data field in which the last section number of the sub-table to which the section belongs is set.

  A field 151i (transport_stream_id) is a 16-bit data field in which one of a set for specifying a download content transmission channel is set.

A field 151j (original_network_id) is a 16-bit data field in which one of a set for specifying a download transmission channel is set.
A field 151k (service_id) is a 16-bit data field in which one of a set for designating a download transmission channel is set.

  A field 151l (num_of_contents) is an 8-bit data field indicating the number of download contents. In the case of the scan notification SDTT, a fixed value “1” is set.

The field 151m (group) is a 4-bit data field in which group_id is set.
A field 151n (target_version) is a 12-bit data field in which the version number of the content to be updated is set. In the case of the scan notification SDTT, “0xFF” is set.

  A field 151o (new_version) is a 12-bit data field in which the version number of the download content is set. In the case of the scan notification SDTT, “0xFFF” is set.

  A field 151p (download_level) is a 2-bit data field indicating a download level. In the case of SDTT for scan notification, “01” is set and forced download is performed.

  A field 151q (version_indicator) is a 2-bit data field in which a version instruction is set. In the case of the scan notification SDTT, “00” is set and the version designation is invalid.

  A field 151r (content_description_length) is a 12-bit data field in which the total byte length of the schedule loop and the descriptor loop is set.

  Field 151s (schedule_description_length) is a 12-bit data field in which the byte length of the schedule loop is set. In the case of the scan notification SDTT, “0x008” is set and the number of schedule loops is 1.

  A field 151t (schedule_time-shift_information) is a 4-bit data field indicating schedule time shift information. In the case of the scan notification SDTT, “0xF” (single service_id) is set.

  The field 151u (start_time) is a 40-bit data field in which the download start time is set in Japan Standard Time (JST) and Modified Julian Date (MJD). In the SDTT for scan notification, it is used as the startable time of STB scan.

  A field 151v (duration) is a 24-bit data field in which a download content transmission duration is set. In the case of the scan notification SDTT, “0xFFFFFF” is set.

The area 151w (descriptors ()) is an area in which a download content descriptor is stored.
The download content transmission channel is designated by a set of a field 151j (original_network_id), a field 151i (transport_stream_id), and a field 151k (service_id) of the download notification information 150. As an example, values indicating that they are not transmitted by broadcasting are “original_network_id = 0x7FFF”, “transport_stream_id = 0xFFFF”, and “service_id = 0xFFFF”.

<Description of each field of download content descriptor for scan notification>
FIG. 5 is a diagram illustrating a table relating to the data structure of the download content descriptor.
As shown in the figure, the table 160 includes columns 161 to 163.

Column 161 shows the data structure of the download content descriptor.
Column 162 indicates the number of bits allocated to the field of the download content descriptor.

A column 163 indicates remarks related to the field of the download content descriptor.
The download content descriptor is composed of fields 161a to 161w.

The field 161a (descriptor_tag) is an 8-bit data field in which “0xc9” is set.
A field 161b (descriptor_length) is an 8-bit data field in which the descriptor length of the download content descriptor is set.

The field 161c (reboot) is a 1-bit data field in which “0” (continuation operation) is set.
The field 161d (add_on) is a 1-bit data field in which “0” (rewrite) is set.

A field 161e (compatibility_flag) is a 1-bit data field in which “0” is set.
A field 161f (module_info_flag) is a 1-bit data field in which “0” is set.

The field 161g (text_info_flag) is a 1-bit data field in which “0” is set.
A field 161h (component_size) is a 32-bit data field in which “0x00000000” is set.

The field 161i (download_id) is a 32-bit data field in which “0xFFFFFFFF” is set.
A field 161j (time_out_value_DII) is a 32-bit data field in which “0xFFFFFFFF” is set.

The field 161k (leak_rate) is a 22-bit data field in which “0x3FFFFF” is set.
A field 161l (component_tag) is an 8-bit data field in which “0xFF” is set.

The area 161m (compatibleDescriptor ()) is an area that is not used.
A field 161n (num_of_modules) is a 16-bit data field that is not used.

The field 161o (module_id) is a 16-bit data field that is not used.
The field 161p (module_size) is a 32-bit data field that is not used.

A field 161q (module_info_length) is an 8-bit data field that is not used.
A field 161r (module_info_byte) is an 8-bit data field that is not used.

A field 161s (private_data_length) is an 8-bit data field in which the byte length of private_data_byte is set.
A field 161t (private_data_byte) is a private data area in which the byte length is specified by private_data_length.

The field 161u (ISO_639_language_code) is a 24-bit data field that is not used.
The field 161v (Text_length) is an 8-bit data field that is not used.

  The field 161w (text_char) is an 8-bit data field that is not used.

<Operation>
The operation of the CATV system configured as described above will be described. Here, the notification information rewriting process and the reception frequency search process when the retransmission frequency of the transmodulation signal is changed will be described.

<Notification information rewriting process>
FIG. 6 is a flowchart showing the notification information rewriting process.
As shown in the figure, the rewrite unit 114 determines whether or not SDTT has been received (step S101). As a result of the determination, only when the SDTT is received (step S101: YES), it is determined whether or not the received SDTT is a frequency list / change information download notification SDTT (step S102). As a result of the determination, if it is the SDTT of the frequency list / change information (step S102: YES), the received SDTT is discarded (step S103). If not (step S102: NO), the received SDTT is retransmitted (step S104).

  Subsequently, it is determined whether or not a re-transmission frequency change has occurred (step S105). As a result of the determination, only when the retransmission frequency is changed (step S105: YES), the scan notification SDTT is created (step S106), and the version number (version_number) of the created scan notification SDTT is updated. (Step S107).

  Subsequently, it is determined whether or not three minutes or more have elapsed since the scan notification SDTT was transmitted (step S108). As a result of the determination, only when three minutes or more have passed (step S108: Yes), the created scan notification SDTT is transmitted (step S109).

Then, it is determined again whether or not SDTT has been received (step S101).
In addition, the date and time when scanning can be started in the receiving apparatus 104 is set in the scan notification SDTT. The receiving device 104 performs scanning after the designated date and time. As a result, the transmodulation signal in which the retransmission frequency is changed is captured, and the service list (receivable frequency table) in the reception apparatus 104 is updated.

  Note that the scan notification SDTT is sent once every three minutes as an example, but is not limited thereto.

<Receiving frequency search processing>
FIG. 7 is a flowchart showing the reception frequency search process.

  As shown in the figure, the search unit 146 determines whether or not a scan notification SDTT has been received (step S121). As a result of the determination, if the scan notification SDTT is received (step S121: YES), it is determined whether or not the received scan notification SDTT is new (step S122). As a result of the determination, if it is new (step S122: YES), the received scan notification SDTT is stored in the scan notification SDTT holding unit 147 (step S123).

  On the other hand, if the received scan notification SDTT is not new (step S122: NO), the version number included in the scan notification SDTT held in the scan notification SDTT holding unit 147 and the received scan notification SDTT Whether or not the version number has been updated is determined from the version number included in (step S124). As a result of the determination, if it has been updated (step S124: YES), the received scan notification SDTT is stored in the scan notification SDTT holding unit 147 (step S123).

  On the other hand, if the scan notification SDTT has not been received (step S121: NO), it is determined whether or not the scan notification SDTT stored in the scan notification SDTT holding unit 147 has been used. Determination is made (step S125). If the result of the determination is that scanning has been carried out (step S125: NO), it is again determined whether or not a scan notification SDTT has been received (step S121). When the scan is not performed (step S125: YES), the scan start possible time included in the scan notification SDTT held in the scan notification SDTT holding unit 147, the local time notified from the time measuring unit 148, From this, it is determined whether it is after the scan start possible time (step S126). As a result of the determination, if it is after the scan start possible time (step S126: YES), the scan is performed (step S127). Only when a scan is performed and a new reception frequency is found (step S128: YES), it is registered in the reception setting (step S129).

Then, it is determined again whether or not the scan notification SDTT has been received (step S121).
In addition, when downloading of the frequency list / change information is attempted and the download is completed, the reception setting is automatically reset based on the downloaded frequency list / change information, or after notifying the subscriber, Reset according to the subscriber's instructions. If the download fails, the reception setting is automatically reset based on the result obtained by scanning, that is, the retransmit frequency that can be received, or the subscriber is notified after the notification. It may be reset according to the user's instructions.

  As described above, when retransmitted by the CATV system 100 according to the first embodiment using the transmodulation method, if the transmission frequency for retransmission is changed on the digital cable television broadcasting station side, Even when a re-transmission is started from a broadcasting station opened in ST, the STB reception setting can be reset and automatically updated without the trouble of the subscriber.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described with reference to the drawings. The description of the same configuration as that of the first embodiment is omitted.

<Overview in Embodiment 2>
The CATV system in the second embodiment is different from the CATV system 100 in the first embodiment in that the head end is shared. It is assumed that a plurality of digital cable television broadcasting station devices (for example, a head end) in a shared head end environment are operated by an MSO (Multiple System Operator).

“MSO” refers to a business form in which distributed digital cable television broadcasting stations are interconnected and collectively managed and operated.
FIG. 8 is a diagram showing an outline of the scan notification SDTT sent from the head end in a shared head end environment.

  As shown in the figure, a shared headend environment is formed by the CATV system 200a of the digital cable television broadcast station serving as the signal distribution station and the CATV systems 200b and 200c of the digital cable television broadcast stations serving as the participating stations. ing. Also, the translation modulation (hereinafter referred to as TM) 21 and TM22 in the CATV system 200a of the signal distribution station transmit a scan notification SDTT of “group_id = 0x0”. Further, the TM 23 in the CATV system 200b of the participating station or the TM 24 in the CATV system 200c of the participating station transmits a scan notification SDTT of “group_id = 0x1”. That is, in the shared headend environment, group_id is used so that the signal distribution station and the participating stations can operate the scan notification SDTT independently.

  For example, a scan notification SDTT (hereinafter referred to as a signal distribution station SDTT) transmitted from the CATV system 200a of the signal distribution station, and a scan notification SDTT (hereinafter referred to as the SDTV for signal distribution stations 200b, 200c). And two types of scan notification SDTTs are sent in accordance with the operation of the digital cable television broadcasting station.

FIG. 9 is a functional block diagram showing the configuration of the retransmission apparatus according to the second embodiment.
As shown in the figure, the retransmitting apparatus 201 is different from the retransmitting apparatus 101 in Embodiment 1 (see FIG. 2) in that a rewriting unit 214 is provided instead of the rewriting unit 114.

The rewriting unit 214 sets an identifier assigned to the location where the retransmitting apparatus 201 is installed (hereinafter referred to as an installation location identifier) in the scan notification SDTT (see FIG. 4).
The installation location identifier may be an identifier indicating a physical installation location such as a region code assigned to each region, or an identifier indicating a logical installation location such as a signal distribution station and a participating station. Also good.

FIG. 10 is a functional block diagram showing the configuration of the receiving apparatus according to the second embodiment.
As shown in the figure, the receiving device 204 is different from the receiving device 104 in Embodiment 1 (see FIG. 3) in that a searching unit 246 is provided instead of the searching unit 146.

The search unit 246 manages the scan notification SDTT for each installation location identifier.
Accordingly, the scan notification SDTT holding unit 147 holds the scan notification SDTT for each installation location identifier.

  In addition, when sending the scan notification SDTT, the same SDTT is sent to all TSs retransmitted in the digital cable television broadcasting station. However, in the common head end (signal distribution station), both the signal distribution station SDTT and the participation station SDTT may be transmitted.

  As described above, since the scan notification SDTT can be managed for each installation location by the CATV system according to the second embodiment, a bidirectional communication line that notifies that the retransmission frequency has been changed between the installation locations. No need to prepare.

  For example, in MSO, there may be a plurality of locations where retransmission devices are installed. When the retransmission frequency is changed in any of a plurality of retransmission apparatuses, the rewriting unit 214 needs to update the version number set in the scan notification SDTT in all the retransmission apparatuses. However, the CATV system according to the second embodiment eliminates the need for a bidirectional communication line that indicates that the retransmission frequency has been changed between the installation locations.

Normally, the field 151m (group) of the SDTT is “0x0”.
Note that the receiving apparatus 204 manages a maximum of two SDTTs.
The installation location identifier may be set in the field 161o (module_id) of the download content descriptor 160 in addition to the field 151m (group) of the scan notification SDTT 150.

(Embodiment 3)
Next, Embodiment 3 of the present invention will be described with reference to the drawings. The description of the same configuration as that of the first embodiment is omitted.

  The CATV system in the third embodiment is different from the CATV system 100 in the first embodiment in that the reception frequency of the transmodulation signal that is no longer retransmitted is automatically deleted from the reception setting.

FIG. 11 is a functional block diagram illustrating a configuration of the retransmission apparatus according to the third embodiment.
As shown in the figure, the retransmitting apparatus 301 is different from the retransmitting apparatus 101 in the first embodiment in that a rewriting unit 314 is provided instead of the rewriting unit 114.

  The rewriting unit 314 sets an identifier for identifying the terrestrial digital television broadcast that is not retransmitted or is not retransmitted in the scan notification SDTT. As an example, the field 161t (private_data_byte) of the download content descriptor transmitted by the scan notification SDTT is used by 2 bytes, and is an identifier for identifying a digital terrestrial television broadcast that is not retransmitted or is not retransmitted. The original_network_id is set in order.

FIG. 12 is a functional block diagram showing a configuration of the receiving apparatus according to the third embodiment.
As shown in the figure, the receiving device 304 is different from the receiving device 104 in Embodiment 1 in that it includes a search unit 346 instead of the search unit 146.

  The search unit 346 has a field 161t (private_data_byte) of the download content descriptor 160 (see FIG. 5) included in the area 151w (descriptors ()) of the scan notification SDTT (see FIG. 4), that is, private data. When an identifier for identifying the terrestrial digital television broadcast is set in the area, the reception frequency of the transmodulation signal identified by the identifier is deleted from the reception setting.

  The information set in the scan notification SDTT may be the retransmission frequency of the transmodulation signal that is no longer retransmitted, instead of the identifier of the digital broadcast that is no longer retransmitted. It goes without saying that the same effect can be obtained exclusively by using the identifier of the digital broadcast being retransmitted or the retransmission frequency.

  As described above, according to the CATV system in the third embodiment, the retransmitting apparatus 301 uses the scan notification SDTT to transmit the terrestrial digital television broadcast that is not retransmitted or retransmitted to the receiving apparatus 304. Notice.

  Accordingly, the receiving device 304 can automatically delete the reception frequency of the terrestrial digital television broadcast that is no longer retransmitted from the reception setting.

<Others>
Note that one or more functional blocks of the retransmission apparatus or the reception apparatus may be realized by a software program executed in a general hardware system such as an embedded device. The software program is stored in an optical recording medium (for example, CD-ROM), a magnetic recording medium (for example, hard disk), a magneto-optical recording medium (for example, MO), or a semiconductor memory (for example, ROM). Etc.) may be recorded on a recording medium readable by the embedded device and executed by another embedded device. Alternatively, it is recorded on a recording medium readable by an embedded device such as a hard disk provided in a general hardware system such as an embedded device connected via a network, and is read via a transmission path such as a network. It may be executed in another embedded device. Alternatively, it may be executed on a computer that develops a software program for controlling an embedded device.

  One or more functional blocks of the retransmission apparatus or the reception apparatus may be realized as a full custom LSI (Large Scale Integration), or as a semi-custom LSI such as an ASIC (Application Specific Integrated Circuit). It may be done. In addition, logic synthesis is performed from a program written in a hardware description language such as VHDL (Very high speed integrated circuit Hardware Description Language) / Verilog-HDL / SystemC (hereinafter referred to as an HDL program). Information, or programmable logic device such as FPGA (Field Programmable Gate Array) / CPLD (Complex Programmable Logic Device) based on IP (Intellectual Property) core or dynamically reconfigurable dynamically reconfigurable circuit configuration Even if it is realized as a device Good. In addition, an HDL program, circuit information, or IP core is stored in an optical recording medium (for example, a CD-ROM), a magnetic recording medium (for example, a hard disk), a magneto-optical recording medium (for example, an MO), or a semiconductor. The information may be recorded on a computer-readable recording medium such as a memory (for example, a ROM) and downloaded to a programmable logic device via a download cable in another computer. Alternatively, an HDL program, circuit information, or IP core is recorded on a computer-readable recording medium such as a hard disk provided in a general hardware system such as a computer connected via a network, In another computer read via the transmission path, the program may be downloaded to the programmable logic device via a download cable. Alternatively, circuit information logically synthesized from an HDL program, or circuit information arranged or wired, or an IP core may be recorded in a serial ROM and directly downloaded to the FPGA.

  The present invention relates to a retransmission apparatus for retransmitting a digital broadcast, a reception apparatus for receiving the retransmitted digital broadcast, and a digital broadcast system including these, in particular, notification of a change in the retransmission frequency of the digital broadcast. Retransmitting device that notifies the receiving device by using the notified information, and acquiring the retransmission frequency that can be correctly received by the notification, resetting the reception setting without the trouble of the subscriber, or automatically updating It can be used as a receiving apparatus that performs the above and a digital broadcasting system including these.

It is a schematic diagram which shows the structure of the CATV system in Embodiment 1 of this invention. 3 is a functional block diagram illustrating a configuration of a retransmission apparatus according to Embodiment 1. FIG. 3 is a functional block diagram illustrating a configuration of a receiving device in Embodiment 1. FIG. It is a figure which shows the table which concerns on the data structure of download notification information. It is a figure which shows the table which concerns on the data structure of a download content descriptor. It is a flowchart which shows notification information rewriting processing. It is a flowchart which shows a reception frequency search process. It is a figure which shows the outline | summary of SDTT for a scan notification sent from the head end in a common head end environment. 6 is a functional block diagram illustrating a configuration of a retransmission apparatus according to Embodiment 2. FIG. 6 is a functional block diagram illustrating a configuration of a receiving apparatus according to Embodiment 2. FIG. FIG. 10 is a functional block diagram illustrating a configuration of a retransmission apparatus according to Embodiment 3. FIG. 11 is a functional block diagram illustrating a configuration of a receiving device in a third embodiment.

Explanation of symbols

21-24 TM
100 CATV system 101, 201, 301 Retransmission device 102 Mixing unit 103 CATV network 104, 204, 304 Reception device 111 Scan notification SDTT holding unit 112 Timing unit 113 Demodulation unit 114, 214, 314 Rewriting unit 115 Multiplexing unit 116 Modulation Unit 117 retransmission frequency information holding unit 141 reception setting holding unit 142 receiving unit 143 demodulating unit 144 reproducing unit 145 detecting unit 146, 246, 346 exploring unit 147 scan notification SDTT holding unit 148 timing unit

Claims (24)

A re-transmission device that re-modulates and re-transmits a digital broadcast modulated and transmitted by a first modulation method using a second modulation method,
Information for notifying transmission of the first frequency information related to the transmission frequency of the digital broadcast modulated and transmitted by the first modulation method is set as the first notice information,
Information notifying the change of the transmission frequency of the digital broadcast that is re-modulated and re-transmitted by the second modulation method is used as the second notification information.
A retransmitting apparatus comprising: rewriting means for rewriting the first notification information included in the digital broadcast modulated and transmitted by the first modulation method with the second notification information. The transmission frequency of the digital broadcast that is re-modulated and re-transmitted with the second modulation method is set as the retransmission frequency.
The second notification information includes a version number that is updated every time the retransmission frequency is changed,
The retransmission apparatus further includes:
Holding means for holding second frequency information related to the retransmission frequency;
The rewriting means further includes:
(A) When the second frequency information is newly held in the holding means,
(B) When the second frequency information held in the holding means is updated,
(C) The retransmission apparatus according to claim 1, wherein the version number is updated when the second frequency information held in the holding unit is deleted. The first notification information includes first channel information related to a transmission channel of the first frequency information,
The second notification information includes second channel information indicating that the first frequency information is not included in the digital broadcast and is not transmitted,
The rewriting means further includes:
The retransmission apparatus according to claim 1, wherein the first channel information is rewritten to the second channel information. The first notification information includes first time information related to a transmission start time of the first frequency information,
The second notification information includes second time information indicating a time at which an update operation of a transmission frequency of a digital broadcast to be retransmitted ends,
The rewriting means further includes:
The retransmission apparatus according to claim 1, wherein the first time information is rewritten to the second time information. The rewriting means further includes:
(A) When the update operation of the transmission frequency of the digital broadcast to be remodulated and retransmitted by the second modulation method is not scheduled,
(B) In the case where all the digital broadcasts modulated and transmitted by the first modulation method are re-modulated by the second modulation method and not retransmitted, the digital broadcast is modulated by the first modulation method. The re-transmission apparatus according to claim 1, wherein the first notification information contained in the transmitted digital broadcast is deleted. The rewriting means further includes:
2. The retransmission according to claim 1, wherein an identifier assigned to a digital broadcast whose transmission is to be stopped among digital broadcasts that are re-modulated and re-transmitted by the second modulation method is included in the second notification information. apparatus. The rewriting means further includes:
The retransmission apparatus according to claim 1, wherein an identifier assigned to an installation location of the retransmission apparatus is included in the second notification information. The first modulation scheme is OFDM (Orthogonal Frequency Division Multiplexing),
The retransmission apparatus according to claim 1, wherein the second modulation scheme is 64 QAM (64 Quadrature Amplitude Modulation). The first frequency information is a list of transmission frequencies of digital broadcasting that is modulated by the first modulation method and transmitted, and a frequency list / change information indicating change information when the transmission frequency is changed,
The re-transmission apparatus according to claim 1, wherein the first notification information is notification information for notifying transmission of the frequency list / change information. A receiving device that receives a digital broadcast that has been re-modulated and re-transmitted using a predetermined modulation method,
Information that notifies the change of the transmission frequency of the digital broadcast that is modulated and retransmitted by a predetermined modulation method,
A receiving apparatus comprising: search means for searching for a receivable transmission frequency if the notification information included in the digital broadcast modulated and transmitted by a predetermined modulation method is updated. The transmission frequency of the digital broadcast that is modulated and retransmitted by a predetermined modulation method is set as the retransmission frequency.
The notification information includes a version number that is updated every time the retransmission frequency is changed,
The receiving device further includes:
First holding means for holding the notification information;
The exploration means further includes:
With reference to the version information included in the notification information held in the first holding means,
The receiving device according to claim 10, wherein a receivable transmission frequency is searched if a version number of notification information included in a digital broadcast modulated by a predetermined modulation method and retransmitted is updated. . The notification information includes time information indicating a time at which an update operation of a frequency of a digital broadcast to be retransmitted ends.
The receiving device according to claim 10, wherein the searching means further searches after the time specified by the time information. The receiving device further includes:
A reception setting holding means for holding reception setting information in which a receivable transmission frequency and a channel number are associated;
The exploration means further includes:
The reception apparatus according to claim 10, wherein when a transmission frequency that is not registered in the reception setting information is found as a result of the search, information related to the detected transmission frequency is registered in the reception setting information. . The receiving device further includes:
A reception setting holding means for holding reception setting information in which a receivable transmission frequency and a channel number are associated;
The exploration means further includes:
The information related to the transmission frequency that was not found is deleted from the reception setting information when the transmission frequency registered in the reception setting information is not found as a result of the search. The receiving device described. The receiving device further includes:
A reception setting holding means for holding reception setting information in which a receivable transmission frequency and a channel number are associated;
The exploration means further includes:
When the identifier assigned to the digital broadcast whose transmission is to be stopped among the digital broadcasts re-modulated and re-transmitted by a predetermined modulation method is received, the digital broadcast specified by the identifier is received. The information regarding the transmission frequency to delete is deleted from the said reception setting information. The receiver of Claim 10 characterized by the above-mentioned. The notification information includes an identifier assigned to each installation location of a retransmission apparatus that retransmits the digital broadcast,
The receiving device according to claim 10, wherein the search unit manages the notification information for each identifier. The receiving apparatus according to claim 10, wherein the predetermined modulation scheme is 64QAM. The list of transmission frequencies of digital broadcasts to be retransmitted and the change information when the transmission frequency is changed are the frequency list / change information.
The receiving apparatus according to claim 10, wherein the notification information is notification information including channel information indicating that the frequency list / change information is not included in the digital broadcast. A re-transmission device that re-modulates and re-transmits a digital broadcast that has been modulated by the first modulation method and re-transmitted by the second modulation method, and a digital broadcast that has been re-modulated and re-transmitted by the second modulation method A digital broadcasting system having a receiving device for receiving,
Information for notifying transmission of the first frequency information related to the transmission frequency of the digital broadcast modulated and transmitted by the first modulation method is set as the first notice information,
Information notifying the change of the transmission frequency of the digital broadcast that is re-modulated and re-transmitted by the second modulation method is used as the second notification information.
Rewriting means for rewriting the first notification information contained in the digital broadcast modulated and transmitted by the first modulation method with the second notification information;
Searching means for searching for a receivable transmission frequency if the second notification information contained in the digital broadcast modulated and transmitted by the second modulation method is updated. system. A retransmission control method for controlling an apparatus that remodulates and retransmits a digital broadcast modulated by a first modulation scheme and transmitted by a second modulation scheme,
Information for notifying transmission of the first frequency information related to the transmission frequency of the digital broadcast modulated and transmitted by the first modulation method is set as the first notice information,
Information notifying the change of the transmission frequency of the digital broadcast that is re-modulated and re-transmitted by the second modulation method is used as the second notification information.
A re-transmission control method comprising: a rewriting step of rewriting the first notification information included in the digital broadcast modulated and transmitted by the first modulation method with the second notification information. A reception control method for controlling a receiving device that receives a digital broadcast that has been re-modulated and re-transmitted by a predetermined modulation method,
Information that notifies the change of the transmission frequency of the digital broadcast that is modulated and retransmitted by a predetermined modulation method,
A reception control method, comprising: a search step of searching for a receivable transmission frequency if the notification information included in the digital broadcast modulated and transmitted by a predetermined modulation method is updated. A re-transmission device that re-modulates and re-transmits a digital broadcast that has been modulated by the first modulation method and re-transmitted by the second modulation method, and a digital broadcast that has been re-modulated and re-transmitted by the second modulation method A digital broadcast control method for controlling a digital broadcast system having a receiving device for receiving,
Information for notifying transmission of the first frequency information related to the transmission frequency of the digital broadcast modulated and transmitted by the first modulation method is set as the first notice information,
Information notifying the change of the transmission frequency of the digital broadcast that is re-modulated and re-transmitted by the second modulation method is used as the second notification information.
A rewriting step of rewriting the first notification information included in the digital broadcast modulated and transmitted by the first modulation method with the second notification information;
And a search step for searching for a receivable transmission frequency if the second notification information included in the digital broadcast modulated and transmitted by the second modulation method is updated. Control method. A retransmission control program for controlling an embedded device that remodulates and retransmits a digital broadcast that is modulated by a first modulation method and transmitted by a second modulation method,
Information for notifying transmission of the first frequency information related to the transmission frequency of the digital broadcast modulated and transmitted by the first modulation method is set as the first notice information,
Information notifying the change of the transmission frequency of the digital broadcast that is re-modulated and re-transmitted by the second modulation method is used as the second notification information.
Retransmission control that causes the embedded device to execute a rewriting step of rewriting the first notification information included in the digital broadcast modulated and transmitted by the first modulation method with the second notification information. program. A reception control program for controlling an embedded device that receives a digital broadcast that has been re-modulated and re-transmitted by a predetermined modulation method,
Information that notifies the change of the transmission frequency of the digital broadcast that is modulated and retransmitted by a predetermined modulation method,
A reception step that causes the embedded device to execute a search step for searching for a receivable transmission frequency if the notification information included in the digital broadcast modulated and transmitted by a predetermined modulation method is updated. Control program.

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