JP5107362B2 - COMMUNICATION DEVICE AND ITS CONTROL METHOD, COMMUNICATION SYSTEM, DATA TRANSMISSION SYSTEM, COMMUNICATION DEVICE CONTROL PROGRAM, AND RECORDING MEDIUM CONTAINING THE PROGRAM - Google Patents

Description

  The present invention relates to a communication device that is connected to a network and receives data from a server via one or more networks including the network, a control method thereof, a communication system, a data transmission system, a communication device control program, and the program. The present invention relates to a recorded recording medium. Specifically, the present invention relates to a communication device that receives content transmitted from a server.

  Content such as video and audio provided from a content providing apparatus such as a content server outside the home is transmitted to an in-home TV (television) receiver (hereinafter referred to as “TV”) via an access network such as an NGN (Next Generation Network) network. In other words, a streaming reception service is provided by an STB (Set Top Box) or the like. When data from the access network is transmitted to the home, the data is once received by a gateway (router) and transferred to a communication device (TV, STB, etc.) serving as a content receiving terminal via the network constructed in the home. The In general, Ethernet (registered trademark) is used for the connection between the router and the receiving terminal, but when the router and the communication device are installed in different rooms, It is necessary to lay an Ethernet (registered trademark) cable.

  On the other hand, power line communication (PLC) is a technique for performing data transmission through a power line, and does not require any special work and can communicate between ordinary outlets. If a bridge device (PLC adapter) between a PLC and Ethernet (registered trademark) is connected to a router and a communication device via Ethernet (registered trademark), the PLC can be used even when the router and the communication device are arranged apart from each other. The router and the communication device can communicate with each other via the adapter, and a home network can be constructed without installing a new cable. A similar home network can also be constructed using a bridge device between a wireless LAN and Ethernet (registered trademark).

  In such a system, the communication device receives high-speed and high-quality content, particularly stream data that requires immediacy (real-time property) and continuity, such as moving images and audio, from the content providing device. In each network, it is necessary to secure a sufficient bandwidth according to the content.

  In general, when viewing content with such a system, the content providing apparatus outside the home, in response to a request from the user, first, the content content that can be provided by a content list, an electronic content guide (ECG), or the like When a request for viewing a content selected by the user based on the content is received, a method of transmitting the content to the communication device is often adopted in VoD (video on demand) or the like. Alternatively, the content providing apparatus notifies the user of the contents that can be provided by an electronic program guide (EPG) or the like via the communication apparatus, and distributes the same stream data to a plurality of recipients. Is used in IP broadcasting and the like.

  However, a content providing device such as a server cannot know the bandwidth usage status or allocation status in a home network constructed by power line carrier communication or the like ahead of the gateway in the user's home, and the bandwidth in the home network The actual situation is that entrustment must be entrusted to the user (or a device constituting the home network). Therefore, when the content is received at the gateway via the access network and then transferred to a home network different from the access network as in the above system, the distributed content is disturbed by the communication device. In order to be received without any problems, it is necessary to secure a bandwidth even in the above-described home network. That is, it is necessary for a user (or a device constituting the home network) to secure a bandwidth of the home network necessary for content reception.

  By the way, there may be a case where the user switches to another content while viewing a certain content. For example, this corresponds to the case where the user selects a content different from the content currently being viewed in VoD and the case where the user is switching the channel being viewed in the IP broadcast to another channel. Or, even if the user does not explicitly instruct, there may be a case where another content is continuously received after the received content is completely received by the communication device. For example, for IP broadcasting, this corresponds to the case where the program being received by the communication device is terminated and reception of the next program is started.

  In this way, when the content to be received is switched, there is a possibility that the necessary bandwidth differs between the content received earlier and the content received later. In this case, when the bandwidth of the content after switching becomes insufficient, it becomes necessary to re-secure the bandwidth. For this reason, how to secure the bandwidth of the home network is an important issue.

  In addition, in the multicast in the IP broadcast described above, IGMP (Internet Group Management Protocol) is used to control the selection of the content. In this case, when the communication device starts viewing the content, the communication device sends a signal called a join packet to join the multicast group at the multicast point (that is, the communication device joins the multicast distribution destination of the content). ). On the other hand, when the content viewing ends, the communication device sends out a leave packet and withdraws from the participating multicast group.

  By the way, when a leave packet is transmitted, the multicast point confirms that there is no other communication device viewing the content, and then ends the distribution of the stream data. That is, when content to be viewed in multicast is switched, there may occur a case where stream data of both content before and after switching temporarily flows in the home network at the same time.

  FIG. 27 shows a sequence when contents to be viewed in multicast are switched. It is assumed that the content A is distributed from the multicast point to the communication device 101 and the communication device 102. Here, when the content to be viewed by the communication device 102 is switched from the content A to the content B, the leave packet for notifying the end of viewing of the content A from the communication device 102 to the multicast point and the start of viewing of the content B are started. A join packet to be notified is transmitted.

  However, at this stage, since the communication device 101 has not yet finished viewing the content A, the stream data of the content A continues to flow from the multicast point and reaches the network interface of the communication device 102. The delivery of the content A can be stopped only after the communication device 101 transmits a leave packet that notifies the multicast point of the end of viewing of the content A. As a result, both the stream data of the content A and the content B simultaneously flow through the network during the period from when the communication device 102 sends the content B join packet to when the communication device 101 sends the content A leave packet. It will be.

  In addition, even when only the communication device 102 is viewing the content A in FIG. 27, after the leave packet is transmitted from the communication device 102 to the multicast point, the multicast point is viewing other content. It takes some time (for example, about 1 second) until it is confirmed that there is no communication device. During this time, the stream data of both content A and content B arrives at the communication apparatus 102.

  In this way, when the content to be viewed in the multicast is switched, the bandwidth used in the home network is increased as compared with the case of receiving individual content, the bandwidth for receiving the content is insufficient, and the content is not disturbed. There is a possibility that it cannot be received. For this reason, how to secure the bandwidth of the home network becomes a more important problem.

Conventionally, as a technique for securing bandwidth in a network close to the user, the user selects a desired content from the content held by the server and notifies the server, and the server is necessary for receiving the selected content. Band information is transmitted to a terminal via a base station, and the terminal requests a band change from a relaying base station based on the band information and sets a new band ( Patent Documents 1 and 2).
Japanese Patent Publication “Japanese Patent Laid-Open No. 2002-247131 (Publication Date: August 30, 2002)” Japanese Patent Publication “Japanese Patent Laid-Open No. 2004-274700 (Publication Date: September 30, 2004)”

  However, in the band setting methods described in Patent Documents 1 and 2, the user can select the content and the wireless terminal (corresponding to the communication device on the user side) notifies the server for the first time to cope with the selected content. The received band information is received, and the base station that manages the band is requested to change the band based on the received band information. In this method, when the content is switched due to a user operation or the passage of time, it is necessary to change the band. At this time, the following problem occurs.

  First, since the band information is acquired after the content is switched, the timing for securing the band is delayed. Here, when transmission of content is started without securing a band, the period from the start of content transmission to the completion of securing the band is best effort transmission. In this part, there is a possibility that the video and audio are disturbed. In other words, the longer the timing for securing the band, the longer the period during which there is a risk of video or audio disturbance. In addition, when the content transmission is started after the bandwidth is secured, the start of the content transmission is delayed as the bandwidth securing timing is delayed. It takes time before you can resume viewing content.

  Second, if the bandwidth required for transmission of content after switching increases compared to before switching, and the bandwidth has already been used for transmission of other traffic, the bandwidth of the entire network Is insufficient, and there is a possibility that a sufficient band cannot be secured for transmission of the content after switching. In this case, when transmitting the content after switching, the video and audio are disturbed.

  Further, when the bandwidth setting methods of Patent Documents 1 and 2 are applied to multicast, the bandwidth that the base station secures after the content is switched is only the bandwidth required for the content that is scheduled to be received after the switching. Therefore, when content is switched, if the stream data of both content before and after switching temporarily flows through the network at the same time, the bandwidth required for receiving the content is the bandwidth reserved by the base station. There was a problem that the content could not be received without disturbance.

  Therefore, in view of such circumstances, it is an object of the present invention to provide a communication device or the like that can reliably receive switched data without delay when receiving data by switching from one data to another.

  A communication apparatus according to the present invention is a communication apparatus that is connected to a network and receives data from a server via one or more networks including the network, and is related to the data in order to solve the above problem The related information acquisition means for acquiring related information relating to a plurality of the data, the related information acquisition means acquiring related information including at least information on a necessary band that is a necessary band for transmitting the data, and the related information acquiring means Based on the related information, the network determination unit determines a sufficient bandwidth which is a sufficient bandwidth when transmitting any of the target data, and the network so as to set the sufficient bandwidth determined by the bandwidth determination unit. And bandwidth setting requesting means for making a request to a management device that manages data transmission in the network.

  The communication apparatus control method according to the present invention is a communication apparatus control method for receiving data from a server via one or more networks connected to a network and including the network. Therefore, a related information acquisition step for acquiring related information related to the data, the related information including at least information on a necessary band that is a band necessary for transmitting the data, with respect to the plurality of data, Based on the related information acquired in the related information acquisition step, a bandwidth determination step for determining a sufficient bandwidth that is sufficient for transmitting any of the target data, and a determination in the bandwidth determination step The bandwidth setting request step for making a request to the management device that manages the transmission of data in the network so that the sufficient bandwidth is set. It is characterized in that it comprises and.

  According to the above configuration and method, first, related information related to data received from the server is acquired with respect to the plurality of data, and a sufficient bandwidth is determined based on a necessary bandwidth included in the acquired plurality of related information. A request is made to the management apparatus to set the determined sufficient bandwidth. Since the bandwidth reserved by the management device by this request is sufficient for transmitting the switched data, the switched data can be received without delay and with certainty.

  The related information may be acquired from a server or may be acquired from another device. Further, it may be acquired upon request, or may be acquired from information broadcast periodically, such as an electronic program guide. Further, the server requesting the related information may be the same as or different from the server requesting the data.

  The communication apparatus according to the present invention further comprises setting means for setting a first time zone including the current time, and the band determining means is data that can be received in the first time zone set by the setting means. May be determined as the target data. In this case, even if the data is switched to any of the data scheduled to be distributed in the first time zone, a sufficient bandwidth is ensured for transmission, so that the switched data can be reliably received without delay. .

  In the communication apparatus according to the present invention, the setting means further sets a second time zone starting from a time after the end of the first time zone, and the bandwidth determining means is set by the setting means. The sufficient bandwidth may be determined by adding data that can be received in the second time zone to the target data. In this case, even if the data is switched to one of the data scheduled to be distributed in the first time zone, a sufficient band for transmission is secured, and the distribution is scheduled to be performed in the second time zone as time elapses. Even if the data is switched to one of the data, a sufficient bandwidth is ensured for transmission, so that the switched data can be received without delay and with certainty.

  The communication apparatus according to the present invention further includes setting means for setting a first time zone including the current time and a second time zone starting from a time after the end of the first time zone, The band determining unit determines the sufficient band as data to be received as data that can be received in the second time zone set by the setting unit, and from the band secured in the first time zone If the sufficient bandwidth is larger, the bandwidth setting request means may make a request to the management apparatus to set the sufficient bandwidth before the start of the second time zone.

  In this case, the sufficient bandwidth is secured by the management device at the beginning of the second time zone. Therefore, any data scheduled to be distributed in the second time zone can be reliably received without delay from the beginning of the second time zone.

  The communication apparatus according to the present invention further includes setting means for setting a first time zone including the current time and a second time zone starting from a time after the end of the first time zone, The band determining unit determines the sufficient band as data to be received as data that can be received in the second time zone set by the setting unit, and from the band secured in the first time zone If the sufficient bandwidth is smaller, the bandwidth setting request unit may make a request to the management device to set the sufficient bandwidth after the end of the first time zone.

  In this case, after the end of the first time zone, the bandwidth secured by the management device is changed from the bandwidth secured in the first time zone to the sufficient bandwidth. Therefore, the data received in the first time zone can be received without delay until the end of the first time zone, and any data scheduled to be distributed in the second time zone can be received without delay. And it can be received reliably.

  In the communication device according to the present invention, the setting means sets the earliest time among the scheduled times when reception of data that can be received at the beginning ends for each of the first and second time zones as the end. Also good. In this case, for each of the first and second time zones, the data that can be received in the time zone is the same as the data that can be received at the beginning of the time zone. Therefore, the bandwidth determination unit may determine a sufficient bandwidth using the data that can be received at the beginning of each of the first and second time zones as the target data, and can simplify the determination process. .

  In the communication apparatus according to the present invention, the setting means may set the start and end of the first time zone and the start and end of the second time zone based on a predetermined rule. In this case, the first and second time zones can be easily set by the setting means. As examples of the predetermined rule, the start time of each time zone is either 00 minutes or 30 minutes, the duration of each time zone is 30 minutes, and the first time zone is the current time. Or until a predetermined period (for example, 6 hours) elapses.

  In the communication apparatus according to the present invention, the setting unit may set the end of the first time zone as the start of the second time zone. In this case, even if the data scheduled to be delivered in the first time zone is continuously switched to any data scheduled to be delivered in the second time zone, a sufficient bandwidth is secured for transmission. Therefore, the switched data can be received reliably and without delay.

  Note that the start of the first time zone is preferably the current time. In this case, data that cannot be received because transmission from the server has already been completed can be excluded, and a more appropriate bandwidth can be secured.

  In the communication apparatus according to the present invention, the bandwidth determination means includes first data that is currently received data, and second data that is one or more data scheduled to be received after completion of reception of the first data. May be determined as the target data. In this case, even if the received data is switched from the first data to the second data with the passage of time, a sufficient bandwidth is ensured for transmission, so that the switched data can be transmitted without delay. And it can be received reliably.

  In the communication apparatus according to the present invention, the bandwidth determination means sets the second data that is one or more data scheduled to be received after the end of reception of the first data that is currently being received as the target data. If the sufficient bandwidth is larger than the bandwidth secured during the reception of the first data, the bandwidth setting requesting means determines the scheduled reception start time for the second data. Before that, the management apparatus may be requested to set the sufficient bandwidth.

  In this case, the sufficient bandwidth is secured by the management device at the scheduled reception start time of the second data. Therefore, the second data can be reliably received without delay from the scheduled reception start time.

  In the communication apparatus according to the present invention, the bandwidth determination means sets the second data that is one or more data scheduled to be received after the end of reception of the first data that is currently being received as the target data. If the sufficient bandwidth is smaller than the bandwidth reserved during the reception of the first data, the bandwidth setting requesting means determines the scheduled reception end time of the first data. Later, the management apparatus may be requested to set the sufficient bandwidth.

  In this case, after the scheduled reception end time of the first data, the bandwidth secured by the management device is changed from the bandwidth secured during the reception of the first data to the sufficient bandwidth. Accordingly, the first data can be reliably received without delay until the scheduled reception end time, and the second data can be reliably received without delay.

  In the communication apparatus according to the present invention, the band determination unit may determine the sufficient band using the data corresponding to the related information acquired by the related information acquisition unit as the target data. In this case, even if the first data is continuously switched to the second data, a sufficient bandwidth is ensured for transmission, so that the switched second data is received without delay and with certainty. Can do.

  In the communication apparatus according to the present invention, the band determination unit may determine the sufficient band using the data corresponding to the related information acquired by the related information acquisition unit as the target data. In this case, even if the data is switched to any data corresponding to all the related information, a sufficient band is ensured for transmission, so that the switched data can be received reliably without delay.

  It is preferable that the bandwidth determination unit determines the sufficient bandwidth using the data that can be received from the server among the data corresponding to the related information acquired by the related information acquisition unit as the target data. In this case, since the data corresponding to the related information and cannot be received from the server can be excluded from the target data, the sufficient bandwidth can be determined appropriately and quickly.

  In the communication apparatus according to the present invention, the band determining unit may set the maximum band among the necessary bands of the target data as the sufficient band. By setting the maximum necessary bandwidth as a sufficient bandwidth, each of the target data is secured with a sufficient bandwidth for transmission, so that it can be reliably received without delay.

  Further, when data is switched, it is possible that both the data before switching and the data after switching are transmitted on the network. Therefore, in the communication apparatus according to the present invention, the band determining means may set the sufficient band as the sum of the largest band and the second largest band among the necessary bands of the target data. In this case, since a sufficient bandwidth is ensured to transmit both the data before switching and the data after switching, the switched data can be reliably received without delay.

  In addition, if the communication system includes a network, a management device that is connected to the network and manages transmission of data in the network, and a communication device configured as described above that is connected to the network, the same effect as described above There is an effect.

  The network is assumed to be a local area network in a building because a communication device used by a general user is connected. An example of such a network is a power line carrier communication network. In the case of a power line carrier communication network, a power line laid in a building can be used as a communication medium, so that it is not necessary to lay a new network cable in the building.

  Note that the data transmission system may include a communication system configured as described above and a server connected to the communication system via a network of the communication system or a network different from the network and transmitting data to the communication device. Thus, the same effects as described above can be achieved.

  Each unit of the communication device can be executed on a computer by a communication device control program. Further, by storing the communication device control program in a computer-readable recording medium, the communication device control program can be executed on an arbitrary computer.

  As described above, the communication device according to the present invention acquires related information related to data received from a server with respect to a plurality of the above-described data, and sets a sufficient bandwidth based on necessary bandwidths included in the acquired plurality of related information. Since the management device is requested to determine and set the determined sufficient bandwidth, the bandwidth reserved by the management device by this request is sufficient to transmit the switched data. Therefore, there is an effect that the switched data can be reliably received without delay.

It is a block diagram which shows the basic structural example of the communication system with which this invention is applied. It is the schematic which shows the structure of the content delivery system which is one Embodiment of this invention. It is a block diagram which shows the principal part structure of STB in the said content delivery system. It is a figure which shows an example of the relevant information of a content memorize | stored in the relevant information storage part of the said STB in a table format. It is a sequence diagram which shows the flow of the data transmitted in the said content delivery system. It is a flowchart which shows the flow of a process in the VoD server of the said content delivery system, PLC main | base station, and STB. It is a flowchart which shows the detail of the band determination process in the said STB. It is the schematic which shows the structure of the content delivery system which is another embodiment of this invention. It is a sequence diagram which shows the flow of the data transmitted in the said content delivery system. It is a flowchart which shows the flow of a process in the multicast point of the said content delivery system, an EPG server, PLC main | base station, and STB. It is a figure which shows an example of EPG which the said EPG server transmits in a table format. It is a sequence diagram which shows the flow of the data transmitted in the content delivery system which is another embodiment of this invention. It is a flowchart which shows the flow of a process in STB of the said content delivery system. It is explanatory drawing which shows an example of said EPG and sufficient band determined from this EPG. It is a flowchart which shows the detail of the process which determines the said sufficient zone | band. It is a figure which shows the band table which the band determination part of the content delivery system which is further another embodiment of this invention determined the band and stored in the determination band memory | storage part by a table format. It is a flowchart which shows the flow of a process in STB of the said content delivery system. It is a flowchart which shows the detail of the process in which the said band determination part determines the said band. It is a flowchart which shows the detail of the process which determines sufficient band B (c, t) in the flow of the process in the said STB. It is a figure which shows the band table which the band determination part of the content delivery system which is further another embodiment of this invention determined the band and stored in the determination band memory | storage part by a table format. It is a flowchart which shows the flow of a process in STB of the said content delivery system. It is a flowchart which shows the detail of the process in which the said band determination part determines the said band. It is a flowchart which shows the detail of the process which determines sufficient band B (c, t) in the flow of the process in the said STB. It is a figure which shows the band table which the band determination part of the content delivery system which is further another embodiment of this invention determined the band and stored in the determination band memory | storage part by a table format. It is a flowchart which shows the flow of a process in STB of the said content delivery system. It is a flowchart which shows the detail of the process in which the said band determination part determines the said band. The sequence in the case where the content to be viewed in the multicast in the conventional content distribution system is switched is shown. It is a flowchart which shows the flow of a process in STB of the content delivery system which is another embodiment of this invention. It is a flowchart which shows the flow of a process in STB of the content delivery system which is other embodiment of this invention. It is a figure which shows an example which displays on a TV the bandwidth reservation state which shows whether the required bandwidth of a content has been ensured. It is a figure which shows another example which displays the said band secured state on TV. It is a figure which shows an example of the bar graph which put together the said required zone | band and the zone currently secured. It is a figure which shows another example of the bar graph which put together the said required band and the band currently secured. It is a figure which shows an example which superimposes the said band ensuring state on the partial area | region of the video content currently displayed, and displays on TV. It is a figure which shows an example of the said band ensuring state displayed on the said area | region. It is a figure which shows another example of the said band secured state displayed on the said area | region. It is a figure which shows another example of the said band secured state displayed on the said area | region. It is a figure which shows another example of the said band secured state displayed on the said area | region. It is a figure which shows another example of the said band secured state displayed on the said area | region. It is a figure which shows another example of the said band secured state displayed on the said area | region. It is a figure which shows another example which displays the said band secured state on TV. It is a figure which shows another example which displays the said band secured state on TV. It is a figure which shows another example of the said band secured state displayed on the said area | region. It is a figure which shows another example of the said band secured state displayed on the said area | region. It is a figure which shows another example of the said band secured state displayed on the said area | region. It is a figure which shows another example of the said band secured state displayed on the said area | region. It is a figure which shows another example which displays the said band secured state on TV. It is a figure which shows another example which displays the said band secured state on TV.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication system 2 Server 3 1st network 4 Network relay apparatus 5 Network management apparatus 6 2nd network 7 Communication apparatus 11 Content distribution system 12 VoD server 13 NGN network 14 Home gateway (HGW)
15 PLC master unit 16 PLC network 17 Set top box (STB)
18 / 18a / 18b / 18c PLC adapter 19 device 20 TV receiver 31 control unit 32 storage unit 33 communication unit 34 input unit 35 output unit 41 related information acquisition unit (related information acquisition means)
42 Band decision unit (band decision means, setting means)
43 Selection instruction acquisition unit 44 Band notification unit (band setting request unit)
45 Content acquisition unit 46 Related information storage unit 47 Determination band storage unit 50 IP broadcast server 51 Multicast point 52 EPG server 64 Control unit 67 Band information acquisition unit

  An embodiment of the present invention will be described below with reference to FIGS. 1 to 7, 30, and 31.

  FIG. 1 is a block diagram showing a basic configuration example of a communication system to which the present invention is applied. As illustrated, the communication system 1 includes a server 2, a first network 3, a network relay device 4, a network management device 5, a second network 6, and a communication device 7. The server 2 is connected to the network relay device 4 via the first network 3, and the communication device 7 is connected to the network relay device 4 via the second network 6. Further, a network management device 5 is connected to the second network 6.

  With such connection, the server 2 and the communication device 7 transmit and receive data via a plurality of networks (network groups) 3 and 6 connected via the network relay device 4. Further, the network management device 5 manages communication in the second network 6 such as setting a communication band between devices in the second network 6.

  In the present embodiment, the server 2 and the communication device 7 communicate with each other via the two networks of the first network 3 and the second network 6, but the server 2 and the communication device. 7 may communicate via one or more arbitrary numbers of networks.

[Embodiment 1]
Next, a more specific configuration of the communication system 1 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a schematic diagram showing the configuration of the content distribution system 11 to which the present invention is applied. 2, it can be easily understood how the simplified basic configuration of FIG. 1 is actually configured. However, the configuration of the system in FIG. 2 is an example, and various other configurations are possible.

  In FIG. 2, the server 2 corresponds to the VoD server 12, the first network 3 corresponds to the NGN network 13, the network relay device 4 corresponds to the home gateway 14, and the communication device 7 corresponds to the set top box 17. The network management device 5 corresponds to the PLC master unit 15, and the second network 6 corresponds to the PLC network 16 which is power line carrier communication.

  Hereinafter, the home gateway is represented as “HGW”. Further, instead of the NGN network 13, other access networks may be used. For example, ADSL (Asymmetric Digital Subscriber Line) or FTTH (Fiber to the Home) may be used.

  Furthermore, a PLC adapter 18 is provided between the PLC network 16 and various devices. The PLC adapter 18 is a device that mutually converts an Ethernet (registered trademark) signal and a PLC signal. The HGW 14, the STB 17, and the other device 19 have a terminal for Ethernet (registered trademark), and are connected to the PLC adapter 18 with an Ethernet (registered trademark) cable, thereby allowing the PLC adapter 18 and the PLC network 16 to pass through. Can communicate with each other.

  In the following, as shown in FIG. 2, when specifically indicating each of the PLC adapters 18 connected to the HGW 14 and the STB 17, reference numerals 18 a and 18 c are used. Further, when the PLC adapter 18 connected to the PLC master unit 15 is particularly shown, 18b is used as a symbol.

  Furthermore, a TV 20 is connected to the STB 17 as an example of a display device that displays various data such as video content. Note that the TV 20 may incorporate the function of the STB 17 and be connected to the PLC adapter 18 via Ethernet (registered trademark). Similarly, in the example of FIG. 2, the HGW 14, the STB 17, and the device 19 are each connected to the PLC network 16 via the external PLC adapter 18, but the PLC adapter 18 may be incorporated in each. .

  In FIG. 2, it is shown that the PLC master unit 15 is externally connected to the PLC adapter 18 b, but actually the PLC adapter 18 b includes the function of the PLC master unit 15. The function of the PLC master unit 15 is included not only in the PLC adapter 18 b but also in all other PLC adapters 18, and one of the plurality of PLC adapters 18 according to the communication status of the PLC network 16. Can function as the PLC master unit 15. However, in the following embodiment, in order to facilitate understanding of the present invention, it is assumed that the PLC master unit 15 independent of the PLC adapter 18 is connected to a specific PLC adapter 18b.

  Next, details of the content distribution system 11 configured as described above will be described. First, the VoD server 12 distributes stored video content based on a request from a user. The VoD server 12 stores video content data to be provided to the user and related information data such as bit rate, required transmission time, provided price, and the like attached to the video content in a storage unit (not shown). ing.

  Further, when the STB 17 obtains from the user that the user desires to view a certain video content via a remote controller, an operation button (not shown) or the like, the STB 17 requests transmission of the video content. Is transmitted to the VoD server 12 via the PLC network 16 and the NGN network 13. The VoD server 12 transmits the video content corresponding to the received transmission request to the requesting STB 17 in packet form. Then, the STB 17 reconstructs the video content packet received from the VoD server 12 as video content, and provides the video content to the user on the TV 20.

  As described above, in this embodiment and the embodiments described later, video content is adopted as a specific example of data received by a communication device used by a user. Hereinafter, the video content is simply referred to as “content”. Examples of the data include various data such as still image data, audio data, text data, and Web content data in addition to the content.

  By the way, when the VoD server 12 transmits content to the STB 17, it is necessary to secure the transmission band of the networks 13 and 16 on the transmission path as much as necessary for content transmission. If not ensured, in the networks 13 and 16 on the transmission path, packet loss or packet transmission delay occurs, and for example, the finally provided video is disturbed.

  In the form as shown in FIG. 2, the VoD server 12 can manage the transmission band in the network 13 for the NGN network 13 to which the VoD server 12 is directly connected. However, the VoD server 12 is sufficient to transmit content without delay in a network to which the VoD server 12 is not directly connected, that is, a network beyond the HGW 14 that is the network relay device 4 (the PLC network 16 in this embodiment). It is generally impossible to know whether the transmission band is secured.

  Therefore, regarding the PLC network 16, a transmission band (hereinafter referred to as “required band”) required for the PLC master device 15 to transmit the content on the PLC network 16 in response to a request from the STB 17 that is a user side device. ) Is secured.

  FIG. 3 shows a main configuration of the STB 17 in the content distribution system 11. As illustrated, the STB 17 is configured to include a control unit 31, a storage unit 32, a communication unit 33, an input unit 34, and an output unit 35. FIG. 3 shows only the configuration related to the present invention, but the actual STB 17 includes other configurations.

  The control unit 31 comprehensively controls various components in the STB 17. The function of the control unit 31 is realized by a CPU (central processing unit) executing a program stored in a storage element such as a random access memory (RAM) or a flash memory. Details of the control unit 31 will be described later.

  The storage unit 32 includes a storage device such as a RAM or a hard disk drive (HDD), and stores various data and programs. Note that details of data stored in the storage unit 32 in the present embodiment will be described later.

  The communication unit 33 is for performing data communication with various external devices such as the VoD server 12 and the PLC master unit 15 via the PLC network 16 and the like.

  The input unit 34 is for a user to input various information. Examples of the input unit 34 include an operation input device such as an operation button and a keyboard, an image input device such as a camera, and a reception device that receives a signal from a remote controller. The input unit 34 converts the input information into a predetermined data format and transmits it to the control unit 31.

  The output unit 35 is for outputting various information received from the control unit 31 to the outside. In the present embodiment, the output unit 35 includes a transmission device that converts data received from the control unit 31 into a format suitable for transmission to the TV 20 and transmits the data to the TV 20. The output unit 35 may include a display device such as an LCD (Liquid Crystal Display), an audio output device such as a speaker, a printing device that performs printing on a printing medium such as paper, and the like.

  Next, details of the control unit 31 and the storage unit 32 will be described. As shown in FIG. 3, the control unit 31 includes a related information acquisition unit (related information acquisition unit) 41, a band determination unit (band determination unit, setting unit) 42, a selection instruction acquisition unit 43, a band notification unit (band setting request). Means) 44 and a content acquisition unit 45. Further, the storage unit 32 includes a related information storage unit 46 that stores content related information, and a determined band storage unit 47 that stores band information determined by the band determination unit 42.

  The related information acquisition unit 41 acquires related information of content that can be provided by the VoD server 12. Specifically, the related information acquisition unit 41 provides the related information of the content via the communication unit 33 or the like prior to acquiring the content itself based on the instruction acquired from the user via the input unit 34. Request to the VoD server 12. As a result, of the content provided by the VoD server 12, the related information of the content that can be reproduced in the STB 17 is acquired from the VoD server 12 through the communication unit 33 and the like.

  The related information acquisition unit 41 stores the acquired related information in the related information storage unit 46. Further, the related information acquisition unit 41 transmits part or all of the related information acquired from the VoD server 12 or the related information storage unit 46 to the TV 20 via the output unit 35. Thereby, the user can refer to the related information displayed on the TV 20.

  FIG. 4 shows an example of content related information stored in the related information storage unit 46. In the illustrated example, in the related information, a title name that is information for identifying content and a bit rate that is information on a transmission band of the content are associated with each content. In the example shown in the drawing, related information of contents whose title names are ABC, DEF, GHI, PQR, and XYZ are included, and contents whose title name is “ABC” (hereinafter, such contents are referred to as “content ABC”). .) Indicates that the bit rate required for transmission is 10 Mbps.

  Information provided as content related information from the VoD server 12 needs to include at least a bit rate in order to implement the present invention. However, in order to increase convenience when a user selects content. In addition, the title name and other information may be included. For example, the genre of the content, the name of the actor who appears, and an explanation of the content can be considered.

  In addition, when the number of contents that can be viewed by the user is large, the VoD server 12 may provide related information of some contents without providing related information of all contents at once. . In this case, when the VoD server 12 receives the request for the content related information from the STB 17 again, the VoD server 12 may provide all or a part of the remaining content related information. For example, assuming that there are 100 contents that can be viewed by the user, the VoD server 12 first provides related information of 10 contents, and requests the related information of the contents from the STB 17 by the user's operation. Is received again, the related information of the next 10 contents is provided.

  Note that the numerical values of the bit rate shown in FIG. 4 are examples for convenience of explanation, and are not directly based on actual numerical values. In the example of FIG. 4, the title name is used as information for identifying the content. However, any information can be used as long as the content can be identified, such as a channel number and an ID number.

  For example, when content is identified by title name, there is a possibility that content with the same title name may exist. Therefore, it is desirable to assign an ID number that can uniquely identify the content on the VoD server 12 side to each content. However, for simplification of explanation, in the following, it is assumed that the content can be uniquely identified only by the title name. Further, as described above, further information for increasing convenience when the user selects content may be stored in the related information storage unit 46 in association with the title name.

  In addition, the related information acquisition unit 41 performs the process of requesting and acquiring the related information when the STB 17 is turned on instead of being performed for each instruction from the user, every predetermined period, or for a predetermined period. You may also go every time. Further, if the VoD server 12 performs IP broadcasting, an electronic program guide (EPG) provided by the VoD server 12 can be used as related information of content, although the format is different from that in FIG. An embodiment using an electronic program guide will be described later.

  Further, when the user selects content, the related information acquisition unit 41 preferably transmits at least the title name of the related information to the TV 20 for display. In this case, the user can easily specify the content from the title name displayed on the TV 20. When the server that provides the content itself and the server that provides the related information are different servers, the related information acquisition unit 41 may request and acquire the related information from the server that provides the related information. .

  Returning to FIG. 3, the bandwidth determination unit 42 determines the transmission bandwidth to be secured in the PLC network 16 from the bit rate (bandwidth information) in the related information stored in the related information storage unit 46. The band determining unit 42 stores the determined transmission band in the determined band storage unit 47.

  Specifically, the band determining unit 42 sets the maximum bit rate of all the related information stored in the related information storage unit 46 as the transmission band to be secured in the PLC network 16. In other words, the content that is provided by the VoD server 12 and that should be ensured with a band sufficient to receive the content having the highest bit rate among all the content that can be reproduced in the STB 17 at present. Bandwidth. The operation of the bandwidth determination unit 42 may be performed every time the related information storage unit 46 is updated by the related information acquisition unit 41, or may be performed periodically.

  The selection instruction acquisition unit 43 acquires an instruction to select content desired by the user via the input unit 34 from the user. The selection instruction acquisition unit 43 notifies the band notification unit 44 that the selection instruction has been acquired. Further, the selection instruction acquisition unit 43 reads the related information of the content corresponding to the acquired selection instruction from the related information storage unit 46 and transmits it to the content acquisition unit 45. Note that the selection instruction acquisition unit 43 may transmit only the title name of the related information to the content acquisition unit 45.

  Further, the selection instruction acquisition unit 43 acquires an instruction to switch from the content being received to another content via the input unit 34 from the user. The selection instruction acquisition unit 43 reads the related information of the content corresponding to the acquired switching instruction from the related information storage unit 46 and transmits it to the content acquisition unit 45. In the present embodiment, the selection instruction acquisition unit 43 does not need to notify the band notification unit 44 even when the switching instruction is acquired.

  When the notification from the selection instruction acquisition unit 43 is received, the band notification unit 44 notifies the PLC base unit 15 of the transmission band corresponding to the bit rate read from the determined band storage unit 47 via the communication unit 33 or the like. It is. When the bandwidth notification unit 44 receives a setting completion notification indicating that the PLC base unit 15 has completed the setting of the transmission band from the PLC base unit 15 via the communication unit 33, the bandwidth notification unit 44 acquires the received setting completion notification as content. To the unit 45.

  The content acquisition unit 45 acquires content corresponding to the title name of the related information received from the selection instruction acquisition unit 43 from the VoD server 12 via the communication unit 33 or the like. The content acquisition unit 45 outputs the acquired content to the outside via the output unit 35.

  Specifically, when the content acquisition unit 45 receives the setting completion notification from the bandwidth notification unit 44, the content acquisition unit 45 sends a content transmission request for transmitting the content corresponding to the title name via the communication unit 33 or the like. Transmit to the VoD server 12. Thereby, the VoD server 12 starts transmission of the requested content packet. The content acquisition unit 45 converts the packet received via the communication unit 33 or the like into a video signal that can be output to the TV, and transmits the converted video signal to the TV 20 via the output unit 35, whereby content is transmitted to the TV 20. Is displayed.

  In addition, when the content acquisition unit 45 newly receives related information from the selection instruction acquisition unit 43 while receiving the content, the content acquisition unit 45 determines that the content is to be switched, and the content corresponding to the title name of the newly received related information Is transmitted to the VoD server 12 via the communication unit 33 or the like. As a result, the VoD server 12 starts transmitting a packet of the newly requested content. The content acquisition unit 45 converts the content packet received from the VoD server 12 into the video signal, and transmits the converted video signal to the TV 20 via the output unit 35, whereby new content is displayed on the TV 20. The

  Next, the flow of the processing operation of the content distribution system 11 having the above configuration will be described with reference to FIGS. FIG. 5 is a sequence diagram showing a flow of data transmitted in the content distribution system 11 of the present embodiment. FIG. 6 is a flowchart showing the flow of processing in the VoD server 12, the PLC master device 15, and the STB 17 of the content distribution system 11.

  As is clear from FIG. 2, communication between the VoD server 12 and the STB 17 is performed via the NGN network 13, the HGW 14, the PLC adapters 18 a and 18 c, and the PLC network 16. On the other hand, communication between the PLC master unit 15 and the STB 17 is performed via the PLC adapters 18 b and 18 c and the PLC network 16. Hereinafter, in order to simplify the description, the description of the device that relays data is omitted.

  As shown in FIGS. 5 and 6, first, in the STB 17, the related information acquisition unit 41 requests the VoD server 12 for the related information of the content that can be provided by the VoD server 12 via the communication unit 33 (step S10). . Note that the above request is made when the STB 17 is turned on, when a predetermined time is reached, when the content to be viewed is switched (when the user switches the content, or when a certain content ends. For example, when the user moves to the next content), or at a timing that the user instructs via the input unit 34.

  On the other hand, when receiving the request for content related information from the STB 17, the VoD server 12 transmits the related information of the content that can be provided to the STB 17 that is the request source (step S20). At this time, when there are a plurality of contents that can be provided, the related information of the plurality of contents is arranged in one list and transmitted collectively. When there are a large number of contents that can be provided, the related information of these many contents may be divided into several lists and arranged so that the lists are sequentially transmitted.

  On the other hand, in the STB 17, the related information acquisition unit 41 acquires the related information of the content transmitted from the VoD server 12 via the communication unit 33, and stores (stores) it in the related information storage unit 46 (step S11).

  Note that the VoD server 12 may be able to provide all of the content that it holds, or may select and provide content that matches a predetermined condition from the content that it holds. The predetermined condition may be set based on a contract between the service provider that provides the content and the user who receives the content. For example, whether or not the content can be viewed is set by the content provision fee, For example, whether or not viewing is set for each natural person or corporation having the copyright of the content, and whether or not viewing is set for each genre of the content (movie, sports, drama, animation, etc.).

  Further, as described above, the VoD server 12 may spontaneously transmit the related information of the contents that can be provided at a predetermined timing. In this case, instead of omitting the request for content related information (step S10), the related information acquisition unit 41 of the STB 17 is always in a data receivable state, and when receiving the content related information from the VoD server 12, It can be stored in the related information storage unit 46.

  Further, the STB 17 may continue to hold the related information stored in the related information storage unit 46 until the user instructs the re-acquisition of the related information of the content. In this case, since the user does not need to request and acquire the related information from the VoD server 12 every time the user wants to view the content, the related information can be provided quickly.

  Next, the bandwidth determination unit 42 of the STB 17 refers to the related information on the content stored in the related information storage unit 46 to determine the bandwidth to be secured in the PLC network 16 (step S12). The bandwidth determination unit 42 stores the determined bandwidth in the determined bandwidth storage unit 47.

  FIG. 7 is a flowchart showing details of the process (step S12) in which the band determining unit 42 determines the band. As shown in the figure, first, the bandwidth B to be secured in the PLC network 16 is initialized to 0 Mbps and the counter i is initialized to 1 (step S40). Next, it is determined whether or not the necessary bandwidth for the content (i) is larger than the bandwidth B (step S41), and if necessary, the necessary bandwidth for the content (i) is set in the bandwidth B ( Step S42).

  Here, content (i) represents the i-th content among the content corresponding to the related information stored in the related information storage unit 46. Note that which content corresponds to which content is not particularly related. In the example of FIG. 4, content (1) corresponds to content ABC, content (2) corresponds to content DEF, content (3) corresponds to content GHI, and so on.

  Next, it is determined whether or not the content (i + 1) exists, that is, whether or not related information corresponding to the content (i + 1) is stored in the related information storage unit 46 (step S43). If stored (YES in step S43), after the counter i is incremented by 1 (step S44), the process returns to step S41 to repeat the above operation. On the other hand, if not stored (NO in step S43), the current band B is determined as a transmission band to be secured in the PLC network 16 and stored in the determined band storage unit 47 (step S45). Thereafter, the bandwidth determination process is terminated and the process returns to the original routine.

  That is, the band determination process shown in FIG. 7 is equivalent to the process of selecting the maximum bit rate of the related information stored in the related information storage unit 46 and storing it in the determined band storage unit 47. In the example of FIG. 4, 15 Mbps which is the bit rate (required bandwidth) of the content GHI is obtained as the transmission bandwidth to be secured in the PLC network 16.

  Returning to FIG. 6, the related information acquisition unit 41 of the STB 17 performs processing such as outputting the related information stored in the related information storage unit 46 to the TV 20 via the output unit 35 and displaying it. The user is referred to the related information. Then, when the user selects the title name of the content desired to be viewed and gives an instruction via the input unit 34, the selection instruction acquisition unit 43 acquires the content selection instruction from the user (step S13). .

  At this time, the band notification unit 44 notifies the PLC base unit 15 of the transmission band via the communication unit 33 in order to secure a transmission band corresponding to the bit rate stored in the determined band storage unit 47 in the PLC network 16. (Step S14). For example, in the case of the content related information shown in FIG. 4, even if the transmission band of 15 Mbps is determined as the transmission band to be secured in the PLC network 16 and the user selects the content ABC, for example, the transmission is 15 Mbps instead of 10 Mbps. The PLC master unit 15 is notified to reserve the band for the STB 17.

  Note that the transmission band may be notified to the PLC master unit 15 before the user selects the content to be viewed. That is, the order of step S13 and step S14 may be switched.

  By the way, in the PLC network 16, a band is allocated to a plurality of data transmissions. Therefore, when notifying the transmission band for securing the band (step S 14), the data is identified to the PLC master unit 15. It is necessary to notify the information to do. However, information for identifying this data may be obtained at the time of selecting content. Specifically, this corresponds to a case where a bandwidth securing request (step S14) is made before the user selects content (step S13) as described above. In this case, when the PLC master unit 15 secures the band, the STB 17 cannot specify which data transmission is specifically assigned to the band.

  Therefore, in such a case, when the STB 17 first notifies the PLC master unit 15 of the transmission band for securing the band, the STB 17 does not notify the information for identifying the data, and the content is selected later. It is conceivable to notify information for identifying the selected content.

  On the other hand, when receiving the transmission band notification from the STB 17, the PLC master unit 15 starts the transmission band setting process in the PLC network 16 while considering the band setting status of other devices (step S30). Then, the setting result is notified to the requesting STB 17 (step S31).

  On the other hand, in the STB 17, when the setting result received by the bandwidth notification unit 44 from the PLC master unit 15 via the communication unit 33 is a setting success, the content acquisition unit 45 receives a request for viewing the content selected by the user (content The title name (identification information) corresponding to the content is added to the transmission request and transmitted to the VoD server 12 (step S15). Although not shown in FIGS. 5 and 6, if the setting result is a setting failure, the content acquisition unit 45 displays an error message on the TV 20 and ends the process.

  On the other hand, when receiving the viewing request from the STB 17, the VoD server 12 starts transmitting the content data corresponding to the title name included in the viewing request to the requesting STB 17 in a packet format (step S21). . At this time, the STB 17 starts to receive the content data (step S16). As a result, the content acquisition unit 45 converts the packet format data of the acquired content into a video signal that can be output to the TV, and transmits the converted video signal to the TV 20 via the output unit 35, so that the content becomes the TV 20. The user can view and play the content.

  Thereafter, it is assumed that the user desires to switch to another content for viewing. At this time, the STB 17 uses the related information stored in the related information storage unit 46 by causing the related information acquisition unit 41 to output and display it on the TV 20 in accordance with an instruction from the user via the input unit 34. Present relevant information to the person. Then, the user selects the title name of the content to be switched and viewed, and gives an instruction via the input unit 34. Thereby, the selection instruction | indication acquisition part 43 acquires the switching instruction | indication of the content from a user (step S17).

  At this time, since the transmission band required in the PLC network 16 has already been secured by the previous band notification (step S14), the band notification unit 44 does not need to notify the band again. Then, similarly to step S15, the content acquisition unit 45 adds a title name (identification information) corresponding to the content to the viewing request (content transmission request) of the content selected by the user, and sends it to the VoD server 12. Transmit (step S18).

  On the other hand, when receiving the viewing request from the STB 17, the VoD server 12 starts transmitting the content data corresponding to the title name included in the viewing request to the requesting STB 17 in the packet format (step S22). . At this time, the STB 17 starts to receive the content data (step S19). Thereby, the content acquisition unit 45 converts the packet data of the acquired content into a video signal that can be output to the TV, and transmits the converted video signal to the TV 20 via the output unit 35, so that the switched content is Reproduced and displayed on the TV 20, the user can view the switched content. Thereafter, every time the content is switched, the same processing as steps S17 to S19 and S22 is performed.

  In the example of the content related information shown in FIG. 4, when the user newly selects the content DEF and switches the content while viewing the content ABC, the PLC master unit 15 is necessary for viewing the content DEF. Since the bandwidth of 15 Mbps, which is greater than 13 Mbps, has already been secured, the content acquisition unit 45 can immediately request the VoD server 12 to request viewing of the content DEF.

  Since the PLC adapter 18 connected to the HGW 14 may receive a plurality of contents, when transmitting the contents to the PLC network 16, after determining which contents are the target of band securing. It is necessary to transmit. Therefore, when the target content is changed, it is necessary to notify the PLC adapter 18 that the target content has been changed even if the transmission band to be secured is sufficient.

  Therefore, after step S17, the bandwidth notification unit 44 notifies the PLC master device 15 that the content that is the target of the secured bandwidth has been switched. In this case, since the bandwidth required for the content after switching has already been secured, there is an advantage that the release and re-reservation of the bandwidth will always succeed.

  In the present embodiment, the server that transmits the content and the server that transmits the related information of the content are the same VoD server 12, but may be separate servers. In addition, the plurality of contents that can be viewed are handled as being stored in one VoD server 12, but may be stored separately in the plurality of VoD servers 12.

  As described above, in the present embodiment, a sufficient bandwidth for receiving content having the highest bit rate among all the content provided by the VoD server 12 and currently playable by the STB 17 is provided. The transmission band used in the PLC network 16 is secured in advance. As a result, even if the content is switched, the necessary bandwidth of the switched content is sufficiently secured, so that it is not necessary to perform the bandwidth setting process again when switching the content. Hereinafter, the maximum transmission band is referred to as “sufficient band”.

  When the communication device 7 is an IP telephone terminal, it is conceivable to switch the codec during a call to change the sound quality of the call, or to change from a voice-only call to a voice and video call.

  Therefore, assuming that the sound quality is changed, the codec type supported by the IP telephone terminal may be secured in advance so that the largest band is used. When the codec is changed, the codec supported by each of the transmitting terminal and the receiving terminal is exchanged, and only the codec supported by both can be used. Therefore, if the maximum bandwidth is secured among the bandwidths used by the codec supported by the terminal itself, no more bandwidth is required, so the bandwidth setting process is performed when the codec is switched. There is no need to re-execute. Further, assuming that the call is changed from a voice-only call to a voice / video combined call, a band corresponding to the sum of the voice band and the video band may be secured in advance.

  In addition, it is conceivable that the PLC master unit 15 cannot secure the sufficient bandwidth for the STB 17 because the PLC network 16 is used for transmission of other data. In this case, it is desirable for the PLC master unit 15 to secure as many bands as possible for the STB 17. At this time, content that is disturbed during reproduction can be reduced as much as possible. In the above case, it is desirable that the STB 17 notifies the user by transmitting to the TV 20 and displaying a bandwidth securing state indicating whether or not the necessary bandwidth for each content has been secured.

  FIG. 30 and FIG. 31 show an example of displaying the above-described band securing state on the TV 20. In the example shown in the figure, when the related information of the content is displayed on the TV 20 in step S13 and the user selects the content, the band securing state is displayed on the TV 20 together with the related information.

  Specifically, in FIGS. 30 and 31, a thumbnail image and a title name are displayed for each content as the related information. Also, the white arrow shown in the figure indicates the currently selected content.

  In FIG. 30, the symbol ◯ or symbol X is displayed for each content as the band securing state. A symbol ◯ indicates a state in which a necessary bandwidth for the corresponding content is secured, and a symbol × indicates a state in which the necessary bandwidth for the corresponding content is not secured. The user can grasp that the necessary bandwidth for the content of the title 4 is not secured by referring to the screen shown in FIG.

  In FIG. 30, the band reservation state is indicated by symbols ○ / ×, but other symbols may be used, and icons, colors, characters such as “OK” and “NO” may be used. May be. Further, the bandwidth reservation state column may be omitted, and the bandwidth reservation state may be expressed by a title name character string, a background color, and / or a frame color in the title name column. For example, for a certain content, when the necessary bandwidth is secured, the title name character string is displayed in green, while when the necessary bandwidth is not secured, the title name character string is displayed in red. Is mentioned.

  Further, the band securing state may be expressed by the frame color of the thumbnail image and / or the overall color tone. For example, for a certain content, when a necessary band is secured, a semi-transparent green color is applied to the entire thumbnail image, while when a necessary band is not secured, a semi-transparent red color is applied to the entire thumbnail image. To apply. As described above, any means for expressing information can be used for the band securing state.

  On the other hand, in FIG. 31, the required bandwidth of each content and the currently reserved bandwidth are displayed in a bar graph in the above-described bandwidth secured status column. Specifically, the required bandwidth of each content is displayed as a horizontal bar graph in which black squares are arranged, and the band currently secured is displayed in a horizontal bar graph in which squares (white squares) are arranged. Note that one of the square and the black square in the figure represents a band of about 1 Mbps. Therefore, in the example shown in the figure, the reserved bandwidth is 7 Mbps, and the necessary bandwidth for Title 1 is 7 Mbps.

  By referring to the screen shown in FIG. 31, the user can grasp the necessary bandwidth of each content, and can grasp whether the necessary bandwidth is sufficient for the currently reserved bandwidth.

  In addition, regarding the bar graph of FIG. 31, whether or not the necessary bandwidth is secured may be expressed by the color of the bar graph. For example, when the necessary bandwidth is secured, a horizontal bar graph in which green squares are arranged is displayed. On the other hand, when the necessary bandwidth is not secured, a red bar is arranged on a horizontal bar graph. It is possible. Thereby, the user can grasp | ascertain rapidly whether the said required zone | band is ensured by referring the color of the said horizontal bar graph.

  In addition, regarding the bar graph of FIG. 31, the required bandwidth and the currently reserved bandwidth may be displayed together in one bar graph. In this case, there is no need to secure an area for displaying a bar graph indicating the currently secured band.

  FIGS. 32A and 32B show examples of bar graphs in which the necessary bandwidth and the currently reserved bandwidth are combined into one. In each of FIG. 32 (a) and FIG. 32 (b), the upper stage shows the case where the required band is sufficient for the currently reserved band, and the lower stage shows the case where the required band is insufficient for the currently reserved band. Show.

  In FIG. 32 (a), the square from the left end is changed to a black square by the amount of the necessary band as compared with the square array indicating the band currently secured. And the part which protrudes from the arrangement | sequence of a square is arranged by adding a white x mark to a black square.

  On the other hand, in FIG. 32 (b), compared to FIG. 32 (a), the black square is changed to a green square, and the black square marked with white x is changed to a red square. In FIG. 32 (b), hatching with a diagonal line rising to the left indicates green, and hatching with a vertical line indicates red. The same applies to the other figures.

  As a result, the user can easily grasp that the required bandwidth is sufficient with the currently secured bandwidth due to the presence of the square array as shown in the upper part of FIGS. 32 (a) and 32 (b). If the user has an arrangement of black squares with white marks as shown in the lower part of FIG. 32 (a), or the red squares as shown in the lower part of FIG. 32 (b). If this arrangement exists, it can be easily grasped that the required bandwidth is insufficient with the bandwidth currently secured. Further, the user can easily grasp the amount of the insufficient band by referring to the number of black squares with white marks or the number of red squares.

  Note that the display form shown in FIG. 30 and the display form shown in FIG. 31 may be switchable by the user operating the remote controller or the like to input instruction information into the input unit 34. Further, the image of FIG. 30 or FIG. 31 may be superimposed and displayed on a partial area of the video content being displayed. At this time, the superposed region may be changeable by the user operating the remote controller or the like to input the instruction information to the input unit 34.

[Embodiment 2]
Next, another embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a schematic diagram showing the configuration of the content distribution system 11 of the present embodiment. The content distribution system 11 shown in FIG. 8 is provided with an IP broadcast server 50, a multicast point 51, and an EPG server 52 in place of the VoD server 12 as compared with the content distribution system 11 shown in FIGS. In other respects, other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure which has the function similar to the structure demonstrated in the said embodiment, and the description is abbreviate | omitted.

  Since the server that provides the content is not the VoD server 12 but the IP broadcast server 50 that performs IP broadcast, the content is simultaneously distributed to a group of communication devices in a predetermined time zone. For this reason, when the user wants to view the content, the content cannot be immediately viewed, but the content distribution schedule is determined on the server side, and the schedule is provided by the EPG. Therefore, in the present embodiment, band information required for content transmission is added for each content in the EPG.

  As shown in FIG. 8, in multicast performed by IP broadcast, content data is not transmitted directly from the IP broadcast server 50 but is transmitted via a multicast point 51. A group of communication devices receive content data from the same multicast point 51. In the present embodiment, an EPG server 52 that provides an EPG including content-related information is provided separately from the IP broadcast server 50.

  Next, the flow of the processing operation of the content distribution system 11 having the above configuration will be described with reference to FIGS. FIG. 9 is a sequence diagram showing a flow of data transmitted in the content distribution system 11 of the present embodiment. FIG. 10 is a flowchart showing the flow of processing in the multicast point 51, the EPG server 52, the PLC master device 15, and the STB 17 of the content distribution system 11.

  As is clear from FIG. 8, communication between the multicast point 51 and the STB 17 is performed via the NGN network 13, the HGW 14, the PLC adapters 18 a and 18 c, and the PLC network 16. On the other hand, communication between the PLC master unit 15 and the STB 17 is performed via the PLC adapters 18 b and 18 c and the PLC network 16. Hereinafter, in order to simplify the description, the description of the device that relays data is omitted.

  As shown in FIGS. 9 and 10, first, in the STB 17, the related information acquisition unit 41 requests the EPG server 52 via the communication unit 33 for an EPG including the related information of the content scheduled to be distributed by the IP broadcast server 50. (Step S50). It should be noted that the above request can be made when the STB 17 is turned on, when a predetermined time is reached, when the content to be viewed is switched (when the user switches the channel, or when a certain program ends) For example, when the program moves to the next program), or at a timing specified by the user via the input unit 34.

  On the other hand, when receiving an EPG request from the STB 17, the EPG server 52 transmits an EPG including related information of content to be distributed to the requesting STB 17 (step S70). This EPG generally includes a bit rate, which is program bandwidth information, for each program in addition to the channel, program title name, and program broadcast time included in the EPG. This bit rate varies depending on the content compression method, compression rate, and the like.

  FIG. 11 is an explanatory diagram showing an example of the EPG in a table format. In the illustrated case, on channel CH1, the program (content) AAA is broadcast at a bit rate of 5 Mbps from 8:00 to 9:00, and then the program BBB is broadcast at a bit rate of 10 Mbps from 9:00 to 9:15. Which indicates that. On channel CH2, program GGG is broadcast at a bit rate of 9 Mbps from 8:30 to 11:00, and on channel CH3, program JJ is broadcast at a bit rate of 7 Mbps from 10:10 to 11:00. Is shown. Since the other columns in FIG. 11 are the same, the description thereof is omitted. However, the numerical values of the illustrated bit rates are for convenience of explanation, and are actually determined by the compression method and compression rate of the broadcast content.

  Returning to FIGS. 9 and 10, in STB 17, EPG transmitted from IP broadcast server 50 is acquired by related information acquisition unit 41 via communication unit 33 and stored (stored) in related information storage unit 46 ( Step S51).

  As described above, the EPG server 52 may spontaneously transmit the EPG at a predetermined timing. In this case, instead of omitting the EPG request (step S50), the related information acquisition unit 41 of the STB 17 is always in a data reception state. When the EPG is received from the EPG server 52, the related information storage unit 46 stores the EPG. It can be stored.

  Further, the STB 17 may continue to hold the EPG stored in the related information storage unit 46 until the user instructs the reacquisition of the EPG. In this case, the user does not need to request and acquire the EPG from the EPG server 52 every time he / she wants to view the content, so that the EPG can be provided quickly.

  Next, the bandwidth determination unit 42 of the STB 17 refers to the EPG stored in the related information storage unit 46 to determine the bandwidth to be secured in the PLC network 16 (step S52). The bandwidth determination unit 42 stores the determined bandwidth in the determined bandwidth storage unit 47.

  Note that the band determination process (step S52) performed by the band determination unit 42 is the same as the band determination process shown in FIG. That is, the bandwidth determination process in the present embodiment is a process of selecting the maximum bit rate of all the related information included in the EPG stored in the related information storage unit 46 and storing it in the determined bandwidth storage unit 47. Is equivalent to

  In other words, it is sufficient to receive the content with the highest bit rate among all the contents (including contents of all channels) scheduled to be distributed by the IP broadcast server 50 during all the broadcast hours included in the EPG. This is a transmission band to be secured. In the example of FIG. 11, the bit rate of 15 Mbps for the content CCC is obtained as a transmission band to be secured in the PLC network 16.

  Next, the related information acquisition unit 41 of the STB 17 performs processing such as outputting the EPG stored in the related information storage unit 46 to the TV 20 via the output unit 35 and displaying the EPG. Refer to EPG. Then, when the user selects the title name or channel of the content desired to be viewed and gives an instruction via the input unit 34, the selection instruction acquiring unit 43 acquires the content selection instruction from the user (step). S53).

  At this time, the band notification unit 44 notifies the PLC base unit 15 of the transmission band via the communication unit 33 in order to secure a transmission band corresponding to the bit rate stored in the determined band storage unit 47 in the PLC network 16. (Step S54). For example, in the case of the EPG shown in FIG. 11, even if a transmission band of 15 Mbps is determined as the transmission band to be secured in the PLC network 16 and the user selects the content AAA at 8:00, for example, 15 Mbps instead of 5 Mbps The PLC master unit 15 is notified to reserve the transmission band for the STB 17.

  Note that the transmission band may be notified to the PLC master unit 15 before the user selects the content to be viewed. That is, the order of step S53 and step S54 may be switched.

  On the other hand, when receiving the transmission band notification from the STB 17, the PLC master device 15 starts the transmission band setting process in the PLC network 16 in consideration of the band setting status of other devices (step S80). Then, the setting result is notified to the requesting STB 17 (step S81).

  On the other hand, in the STB 17, when the setting result received by the bandwidth notification unit 44 from the PLC master unit 15 via the communication unit 33 is a setting success, the content acquisition unit 45 uses information for identifying the content selected by the user. A viewing request with a certain channel added is transmitted to the multicast point 51. Specifically, the content acquisition unit 45 transmits to the multicast point 51 the join packet for notifying the start of viewing of the content including the multicast address corresponding to the channel for which reception is to be started (step S55). Although not shown in FIGS. 9 and 10, when the setting result is a setting failure, the content acquisition unit 45 displays an error message on the TV 20 and ends the process.

  On the other hand, when receiving the join packet from the STB 17, the multicast point 51 adds the transmission source STB 17 to the multicast distribution destination of the content (step S71). Thereby, the content data is distributed from the multicast point 51 to the STB 17 in a packet format.

  On the other hand, the STB 17 starts to receive the content data (step S56). As a result, the content acquisition unit 45 converts the packet format data of the acquired content into a video signal that can be output to the TV, and transmits the converted video signal to the TV 20 via the output unit 35, so that the content becomes the TV 20. The user can view and play the content. In this way, the PLC master unit 15 secures the bandwidth determined from the EPG bandwidth information acquired in advance by the STB 17 that is the receiving-side communication device, and performs communication.

  Thereafter, it is assumed that the user desires to switch to another content for viewing. At this time, in response to an instruction from the user via the input unit 34, the STB 17 causes the EPG stored in the related information storage unit 46 to be output to the TV 20 for display by the related information acquisition unit 41 and displayed. Presents the EPG. Then, the user selects the title name or channel of the content to be switched and viewed, and gives an instruction via the input unit 34. As a result, the selection instruction acquisition unit 43 acquires a content switching instruction from the user (step S57).

  Note that the channels may be switched by an operation that switches the channels in a predetermined order without displaying the EPG. For example, when the channel CH2 is currently being viewed, the operation method may be such that pressing the “+ button” on the remote control switches the channel CH2 to the channel CH3, and pressing the “− button” switches the channel CH2 to the channel CH1. .

  At this time, since the transmission band required in the PLC network 16 has already been secured by the previous band notification (step S54), the band notification unit 44 does not need to perform the band notification again. On the other hand, the content acquisition unit 45 of the STB 17 transmits a viewing end notification added with a channel, which is information for identifying content to be viewed, to the multicast point 51. Specifically, the content acquisition unit 45 sends a leave packet that notifies the end of viewing of the content to the multicast point 51 including the multicast address corresponding to the channel whose reception is to be ended (step S55). Subsequently, as in step S55, the content acquisition unit 45 sends a join packet notifying the start of viewing of the content newly selected by the user to the multicast point 51 (step S59).

  On the other hand, when receiving the leave packet from the STB 17, the multicast point 51 deletes the STB 17 that is the transmission source of the leave packet from the multicast distribution destination of the content (step S72). Subsequently, when receiving the join packet from the STB 17, the multicast point 51 adds the source STB 17 to the multicast distribution destination of the newly selected content (step S73). Thereby, the content data is distributed from the multicast point 51 to the STB 17 in a packet format.

  On the other hand, the STB 17 starts to receive the content data (step S60). Thereby, the content acquisition unit 45 converts the packet data of the acquired content into a video signal that can be output to the TV, and transmits the converted video signal to the TV 20 via the output unit 35, so that the switched content is Reproduced and displayed on the TV 20, the user can view the switched content. Thereafter, every time the content is switched, the same processing as steps S57 to S60, S72, and S73 is performed.

  For example, in the EPG shown in FIG. 11, when the user newly selects the content FFF while switching the content AAA, the PLC master unit 15 starts from 13 Mbps required for viewing the content FFF. Since a large 15 Mbps bandwidth has already been secured, the content acquisition unit 45 can immediately notify the multicast point 51 of the end of viewing the content AAA and the start of viewing the content FFF. As described above, after step S57, the band notification unit 44 may notify the PLC master unit 15 that the content targeted for the reserved band has been switched.

  As described above, in the present embodiment, the maximum band (sufficient band) among the necessary bands of all the contents included in the EPG is secured in advance as the transmission band used in the PLC network 16. As a result, even if the content is switched, the necessary bandwidth of the switched content is sufficiently secured, so that it is not necessary to perform the bandwidth setting process again when switching the content. Moreover, since it is sufficient to secure the bandwidth of the PLC network 16 only once after obtaining the EPG, the burden on the PLC master device 15 can be reduced.

  In the present embodiment, the maximum necessary bandwidth (sufficient bandwidth) is selected for all content broadcast at all times in the EPG, but the time zone during which the target content is broadcast It is also possible to limit. For example, a general EPG contains relevant information for all the content scheduled to be broadcast in the next several days, so the necessary bandwidth is the largest among the content scheduled to be broadcast in that time. A thing (sufficient bandwidth) may be selected. Furthermore, it is possible to limit to a shorter time zone (for example, 6 hours). The limited time zone is desirably a time zone including the current time (first time zone).

  For example, in the EPG of FIG. 11, a method may be considered in which a sufficient bandwidth is determined by focusing only on contents scheduled to be broadcast in the time zone from 8:00 to 9:00. In this case, the target contents are AAA, FFF, III, and GGG, respectively, and the bit rate 13 Mbps of the contents FFF is determined as a sufficient band.

  It is desirable to exclude content that has already been broadcast from the target. In the above example, when the current time is 8:30, content FFF that has already been broadcast is excluded from the target, and therefore the bit rate of 9 Mbps for content GGG is determined as a sufficient bandwidth.

  Or limitation of the time slot | zone (1st time slot | zone) called a predetermined period from the present time is also considered. For example, in the EPG of FIG. 11, the current time is 10:15, and a sufficient bandwidth is determined by focusing on the content scheduled to be broadcast for 60 minutes. In this case, there are six target contents, DDD, GGG, JJJ, EEE, HHH, and KKK, and the bit rate of 12 Mbps for the content EEE is determined as a sufficient band.

  In addition, as described above, there may be a channel that cannot be viewed by the user due to a non-contract. In this case, it is desirable to exclude channels that cannot be viewed from the target. In the above example, when the channel CH1 cannot be viewed, the content DDD / EEE of the channel CH1 is excluded from the target, so that the bit rate 11 Mbps of the content KKK is determined as a sufficient band.

  In STB17, when IP broadcast and VoD can be received simultaneously, the maximum necessary bandwidth is determined from all of content that can be received by IP broadcast and content that can be received by VoD, and the bandwidth is secured. You may do it. The procedure of the content reception service in VoD is as described in the embodiment shown in FIGS. In this case, it is not necessary to perform the bandwidth setting process again even when the IP broadcast is changed to VoD by a user operation or the like (that is, when the service to be received is changed) while viewing the IP broadcast. Therefore, the present invention can be applied to any service that receives content as long as it obtains a list of content and selects content to be received from the list. The same applies when receiving three or more content reception services.

  Further, depending on the service, there is a case where the upper limit of the bit rate of the provided content is determined. For example, when the upper limit of the bit rate is determined as an IP broadcast standard (that is, when it is known in advance that content exceeding a certain bit rate is not provided in any time zone of any channel) ) Even if the bandwidth information is not acquired from the EPG, the same effect as in the present embodiment can be obtained if the bandwidth corresponding to the upper limit of the bit rate is secured. However, even when content with a bit rate lower than the upper limit is transmitted, the upper limit bit rate is always secured, so there are more situations where the actually used bandwidth is less than the allocated bandwidth, and the bandwidth The efficiency of use becomes worse.

[Embodiment 3]
Next, still another embodiment of the present invention will be described with reference to FIGS. 12 to 15 and FIGS. 33 to 37. The content distribution system 11 of the present embodiment is different from the content distribution system 11 shown in FIGS. 8 to 11 only in the functions of the bandwidth determination unit 42 and the bandwidth notification unit 44 and the data structure of the determined bandwidth storage unit 47. Other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  In the present embodiment, the bandwidth determination unit 42 determines a sufficient bandwidth for all contents scheduled to be distributed at a certain time, and stores the determined sufficient bandwidth in association with the above time in the determined bandwidth storage unit 47. This is repeated for other times included in the EPG.

  Then, when the time at which the sufficient bandwidth stored in the determined bandwidth storage unit 47 changes is reached, the bandwidth notification unit 44 notifies the PLC master unit 15 of the changed sufficient bandwidth via the communication unit 33. . Thereby, it is possible to prevent the bandwidth of the PLC network 16 from being wasted.

  Next, the flow of the processing operation of the content distribution system 11 having the above configuration will be described with reference to FIGS. FIG. 12 is a sequence diagram showing a flow of data transmitted in the content distribution system 11 of the present embodiment. FIG. 13 is a flowchart showing the flow of processing in the STB 17 of the content distribution system 11. In addition, since the process of the multicast point 51 of the content delivery system 11, the EPG server 52, and the PLC main | base station 15 is the same as the process shown in FIG. 10, the description is abbreviate | omitted.

  As shown in FIGS. 12 and 13, first, the related information acquisition unit 41 of the STB 17 sends the EPG including the related information of the content scheduled to be distributed by the IP broadcast server 50 to the communication unit 33 as in FIGS. 9 and 10. The EPG server 52 is requested to acquire the EPG, and the acquired EPG is stored (stored) in the related information storage unit 46 (steps S50 and S51).

  Next, the band determining unit 42 of the STB 17 refers to the EPG stored in the related information storage unit 46 to determine a transmission band to be secured in the PLC network 16 at a certain time, and this is included in the EPG. Repeat for other times (step S90). The band determining unit 42 stores the time and the determined transmission band in the determined band storage unit 47 in association with each other.

  FIG. 14 is an explanatory diagram showing an example of the EPG and the transmission band determined from the EPG in a table format. The EPG stored in the related information storage unit 46 is described on the left side of the figure, and the transmission band stored in the determined band storage unit 47 is described on the right side of the figure. The EPG shown in FIG. 14 is the same as the EPG shown in FIG.

  In the example of FIG. 14, the sufficient bandwidth at each time (the maximum value of the necessary bandwidth) is 8:00 to 8:30, the bit rate of the program FFF is 13 Mbps, 8:30 to 9:00, and 10 0:00 to 11:00 is the bit rate of 9 Mbps for the program GGG, 9:00 to 9:15 is the bit rate of 10 Mbps for the program BBB, and 9:15 to 10:00 is the program CCC. The bit rate is 15 Mbps. A bit rate of 12 Mbps for the program EEE is from 11:00 to 12:00. Therefore, these time zones and sufficient bandwidths are associated with each other and stored in the determined bandwidth storage unit 47. The sufficient bandwidth determination by the bandwidth determination unit 42 may be performed once after the EPG is acquired once, and does not need to be performed again when the program is actually switched.

  FIG. 15 is a flowchart showing details of the process (step S90) in which the band determining unit 42 determines the transmission band. As illustrated, first, the time t is set to the distribution start time t0 of the content having the earliest distribution time among all the contents included in the EPG (step S100). In the example of FIG. 14, t0 is 8:00. Next, a channel number i (hereinafter abbreviated as “channel i”) is set to 1 (step S101). Here, it is assumed that the content included in the EPG is assigned to an integer channel number starting from 1.

  Next, it is determined whether or not the time t has reached the distribution start time u of the content (i, u) (step S102). Here, the content (i, u) represents the content whose distribution is started from the time u in the channel i.

  When the time t has not reached the distribution start time u of the content (i, u) (NO in step S102), it is determined whether or not the channel i is the last channel number in the EPG (step S103). If it is not the last channel number (NO in step S103), channel i is incremented by 1 (step S104), and then the process returns to step S102 and the above operation is repeated. On the other hand, if it is the last channel number (YES in step S103), it is determined that there is no content whose time t has reached the distribution start time u, and the process proceeds to step S106.

  On the other hand, when time t has reached distribution start time u of content (i, u) (YES in step S102), sufficient bandwidth B (t) that is the maximum value of the necessary bandwidth at time t is determined, and time t t and the sufficient bandwidth B (t) are associated with each other and stored in the determined bandwidth storage unit 47 (step S105). Thereafter, the process proceeds to step S106. Note that the processing in step S105 is the same as the processing shown in FIG.

  In step S106, time t is advanced by a predetermined time. The predetermined time may be a minimum unit of time described in the EPG, and is generally one minute. Next, it is determined whether or not the time t has reached the last time included in the EPG (step S107). If time t has not reached the last time (NO in step S107), the process returns to step S101 and the above processing operation is repeated. On the other hand, when time t has reached the last time (YES in step S107), the bandwidth determination process is terminated and the process returns to the original routine.

  That is, in the bandwidth determination process (steps S100 to S107) shown in FIG. 15, the sufficient bandwidth B (t) at the time t is determined for each time t when the content distributed on any channel is switched with reference to the EPG. It is determined and stored in the determined band storage unit 47.

  For example, in the EPG shown in FIG. 14, first, when the time t = 8: 00, it is the distribution start time of the program AAA in the channel i = 1, so that the sufficient bandwidth B ( t) is determined. Of the programs distributed at 8:00, the program with the maximum necessary bandwidth is the program FFF, and therefore its bit rate of 13 Mbps is a sufficient bandwidth B (t).

  Subsequently, when time t is advanced and time t = 8: 30 is reached, since it is the distribution start time of program GGG in channel i = 2, sufficient bandwidth B at time t = 8: 30 ( t) is determined. Of the programs distributed at 8:30, the program with the maximum necessary bandwidth is the program GGG, so the bit rate of 9 Mbps is a sufficient bandwidth B (t).

  Subsequently, when time t is advanced to reach time t = 9: 00, since it is the distribution start time of program BBB in channel i = 1, sufficient bandwidth B at time t = 9: 00 ( t) is determined. Of the programs distributed at 9:00, the program with the maximum necessary bandwidth is the program BBB, so that the bit rate of 10 Mbps is the sufficient bandwidth B (t). In the same manner, the maximum value (sufficient bandwidth) B (t) of the necessary bandwidth up to time t = 12: 00 is obtained.

  Returning to FIG. 12 and FIG. 13, as described above, when the selection instruction acquisition unit 43 of the STB 17 acquires a content selection instruction from the user (step S <b> 53), the band notification unit 44 displays a sufficient band of the current time. Is read from the determined band storage unit 47 and notified to the PLC master unit 15 via the communication unit 33 (step S54). Thereby, the sufficient bandwidth is secured in the PLC network 16.

  When the bandwidth notification unit 44 receives the setting result from the PLC master unit 15 via the communication unit 33 and recognizes that the bandwidth setting process has been completed, the content acquisition unit 45 is information for identifying the content selected by the user. A viewing request (join packet) with the added channel is transmitted to the multicast point 51 (step S55). Thereby, the STB 17 starts receiving the content data (step S56). The content acquisition unit 45 converts the packet data of the acquired content into a video signal that can be output to the TV, and transmits the converted video signal to the TV 20 via the output unit 35, whereby the content is reproduced and displayed on the TV 20. The user can view the content.

  In the example of FIG. 14, when the user selects the channel CH1 at 8:00, the determined band storage unit 47 is first referred to and should be reserved in the PLC network 16 from 8:00 to 8:30. A sufficient bandwidth of 13 Mbps is derived and notified to the PLC master unit 15, and the bandwidth of the PLC network 16 is set. This setting depends only on the time stored in the determined band storage unit 47 and the sufficient band, and does not depend on which channel content the user views. Thereafter, a join packet for starting viewing of the content AAA is sent to the multicast point 51, and reception of the content AAA is started in the STB 17.

  Thereafter, as shown below, when any of the three conditions (steps S91, S92, and S96) is satisfied, processing corresponding to the corresponding condition is performed.

  That is, referring to the time stored in association with determined bandwidth storage unit 47 and the sufficient bandwidth, when the time at which the bandwidth to be secured in PLC network 16 changes (YES in step S96), bandwidth notification unit 44 notifies the PLC master unit 15 of the new sufficient bandwidth (step S97). In the example of FIG. 14, when viewing the content III on the channel CH3 from 8:00, the sufficient bandwidth stored in the determined bandwidth storage unit 47 changes from 13 Mbps to 9 Mbps at 8:30. The unit 44 notifies the PLC master unit 15 to set the transmission band of the PLC network 16 to 9 Mbps at 8:30.

  On the other hand, when the user instructs channel switching (YES in step S92), the content acquisition unit 45 of the STB 17 sends a leave packet notifying the end of content viewing to the multicast point 51 (step S93). . The multicast point 51 that has received the leave packet deletes the STB 17 from the multicast distribution destination of the content. Thereby, the transmission of the content from the multicast point 51 to the STB 17 is completed.

  Next, the content acquisition unit 45 of the STB 17 sends a join packet that notifies the start of viewing of the newly selected content to the multicast point 51 (step S94). The multicast point 51 that has received the join packet adds the STB 17 to the multicast distribution destination of the content. Thus, transmission of new content from the multicast point 51 to the STB 17 is started, and the content acquisition unit 45 of the STB 17 starts receiving new content data (step S95).

  In the example of FIG. 14, when the user switches to channel CH3 while viewing the content AAA of channel CH1 from 8:00 to 8:30, first the leave packet for notifying the end of viewing of the content is multicast. A join packet that is transmitted to the point 51 and then notifies the start of viewing of the content III of the channel CH 3 is transmitted to the multicast point 51. As a result, reception of the content III is started in the STB 17. At this time, there is no need to notify the PLC master unit 15 of a request to change the reserved bandwidth. In addition, between step S93 and step S94, the band notification unit 44 may notify the PLC master unit 15 that the content targeted for the secured band has changed from AAA to III. Good.

  In addition, the content viewed by the user is changed to something other than IP broadcast (VoD, etc.), the TV 20 is turned off, the TV 20 is input switched (for example, the display on the TV 20 is switched from the STB 17 to the game machine). If it is determined that viewing of the IP broadcast content has ended (YES in step S91), the content acquisition unit 45 of the STB 17 sends a leave packet notifying the end of viewing of the content to the multicast point 51 ( Step S98). The multicast point 51 that has received the leave packet deletes the STB 17 from the multicast distribution destination of the content. Thereby, the transmission of the content from the multicast point 51 to the STB 17 is completed.

  Furthermore, the bandwidth notification unit 44 of the STB 17 notifies the PLC master device 15 to release the bandwidth secured in the PLC network 16 (step S99). Thereafter, the process ends. Since there is a possibility that the user views the IP broadcast again, the bandwidth may be secured without notifying the release of the bandwidth from the STB 17. In this case, the STB 17 may release the band after determining that the IP broadcast has not been viewed after a predetermined period (for example, about one hour). As a method for determining that the IP broadcast is not viewed, it is possible to detect that a predetermined time has elapsed during which no operation on the STB 17 or the TV 20 (for example, channel change or volume change operation using the remote control) is performed. A camera or a sensor device is provided in the STB 17 or the TV 20 to detect whether a user is present in the vicinity of the STB 17 or the TV 20 and to detect that a period of time when the user is absent exceeds a predetermined time. Can be considered.

  In the present embodiment, when the time stored in the determined band storage unit 47 is reached, the band to be secured in the PLC network 16 is reset. The above-described resetting may be performed when the content that can be viewed is changed. For example, when the EPG changes due to an emergency program or a broadcast extension, it is necessary to reset it. When an EPG is received, whether or not there is a difference from the previously received EPG can be determined to determine whether or not resetting is necessary.

  In the present embodiment, the bandwidth determination unit 42 determines a sufficient bandwidth at each time in advance, but may continue to determine a sufficient bandwidth at the current time. That is, the bandwidth determination unit 42 may determine a sufficient bandwidth for all the content currently being broadcast at a predetermined period (for example, 0.1 second), and store the determined sufficient bandwidth in the determined bandwidth storage unit 47. In this case, the bandwidth notification unit 44 determines whether or not the sufficient bandwidth stored in the determined bandwidth storage unit 47 has changed from the band currently secured in the PLC network 16 at the predetermined cycle. In this case, the sufficient bandwidth after the change may be notified to the PLC master unit 15 via the communication unit 33.

  In the above case, even if the user instructs channel switching and the content is switched, a bandwidth sufficient for transmission has already been secured, so a request to change the secured bandwidth is sent to the PLC master unit 15. There is no need to notify. Further, the bandwidth determination unit 42 does not need to associate the determined sufficient bandwidth with the time. Furthermore, in the bandwidth determination process (step S90) performed in advance before viewing, it is not necessary to determine a sufficient bandwidth at a time other than the current time, so that content can be viewed quickly.

  In the process of switching channels, both the content before switching and the content after switching may be transmitted to the PLC network 16. Therefore, the bandwidth determination unit 42 may determine a sufficient bandwidth as the sum of the maximum bit rate and the second bit rate among the bit rates of all contents scheduled to be distributed at a certain time. . For example, in the EPG of FIG. 14, the sufficient bandwidth in the time zone from 8:00 to 8:30 may be 13 + 8 = 21 Mbps. In this case, both the content before switching and the content after switching can be reliably received without delay.

  In the example of FIG. 14, the bandwidth secured in the PLC network 16 is set to 13 Mbps at 8:00, then changed to 9 Mbps at 8:30, and changed to 10 Mbps at 9:00. , It was changed to 15 Mbps at 9:15. At this time, there is a possibility that a bandwidth for transmitting other data to the PLC network 16 is secured, and a bandwidth of 15 Mbps cannot be secured at 9:15.

  Therefore, the bandwidth determination unit 42 may not request bandwidth setting when the bandwidth to be secured decreases. In this case, the bandwidth to be secured from 8:00 to 9:15 is 13 Mbps.

  Also, instead of changing from a sufficient bandwidth of the current time zone (first time zone) to a sufficient bandwidth of the next time zone (second time zone), a time zone (second time zone) after the current time zone It may be changed to the maximum of the sufficient bandwidth of the time zone.

  In addition, as described above, the PLC master unit 15 may not be able to secure the above-described sufficient bandwidth for the STB 17, and in this case, the STB 17 transmits the above-described bandwidth reservation state to the TV 20 for display. It is desirable to notify the user.

  FIG. 33 shows an example of displaying on the TV 20 the above band securing state superimposed on a partial area of the video content being displayed. In the illustrated example, the band securing state display area 60, which is an area for displaying the band securing state, is provided at the upper right of the video content. However, the band securing state display area 60 may be provided at an arbitrary position of the video content. You may provide so that it may display on arbitrary positions. Further, the band securing state display area 60 may be changeable by the user operating the remote controller or the like to input instruction information to the input unit 34.

  FIG. 34A to FIG. 34C show an example of the bandwidth securing state displayed in the bandwidth securing state display area 60. In the example shown in the figure, the symbol O or symbol X is displayed for each channel as the band securing state. Here, the symbol ◯ indicates a state in which the necessary bandwidth of the content being broadcast is secured on the corresponding channel, and the symbol × indicates a state in which the necessary bandwidth of the content is not secured. Therefore, the user can grasp the channel in which the necessary bandwidth of the content being broadcast is not secured by referring to the images shown in FIGS. 34 (a) to 34 (c).

  In FIG. 34 (a), the above-described bandwidth securing state for two of the channel being viewed and the other channel is displayed. In the example shown in the figure, when at least one necessary bandwidth of the content being broadcast is not secured on a channel other than the channel being viewed, the symbol becomes x, and when all the necessary bandwidth of the content is secured. The symbol is ○. Therefore, the user can grasp that the content to be reproduced may be disturbed when the channel is switched by referring to the image shown in FIG.

  Further, in FIG. 34 (b), the above-described band securing states for three of the channel being viewed and the adjacent channel are displayed. The illustrated example is suitable when the user switches channels using an up button and a down button on a remote controller or the like.

  At this time, a channel for which a necessary bandwidth is not secured may be skipped. For example, in FIG. 34B, it is assumed that the currently displayed channel is channel 3. At this time, channel 2 becomes the previous channel. Furthermore, it is assumed that the necessary bandwidth of channel 1 is secured. In such a case, when the down button is pressed, the video of channel 2 is normally displayed. However, as shown in the figure, the necessary bandwidth of channel 2 is not secured, so channel 2 is skipped and the channel is skipped. 1 video is displayed.

  In FIG. 34 (c), the above-described band securing states for all channels are displayed. In the figure, a symbol> is added to the channel being viewed. The illustrated example is suitable when the user switches channels with a numeric keypad on a remote controller or the like. Note that the channels for which the necessary bandwidth is not secured may be hidden on the illustrated list.

  In FIG. 34 (a) to FIG. 34 (c), the band reservation state is indicated by symbols ○ · ×. However, other symbols may be used, icons, colors, “OK”, “ Characters such as “No” may be used. Further, the area to which the above symbols are attached is omitted, and in the character string column (current channel, previous channel, channel 1, etc.) including “channel”, the band secured state is determined by the character string and / or background color. May be expressed. For example, a channel in which the necessary bandwidth of the content being broadcast is secured displays the character string in green, while a channel in which the necessary bandwidth is not secured is displayed in red. As described above, any means for expressing information can be used for the band securing state.

  FIG. 35A to FIG. 35C show another example of the band securing state displayed in the band securing state display area 60. In the example shown in the figure, as the band securing state, the currently secured bandwidth is displayed as a bar graph, and the necessary bandwidth of the content being broadcast is displayed as a channel-based bar graph. Specifically, the currently reserved bandwidth is displayed as a horizontal bar graph in which squares are arranged, and the required bandwidth of the content being broadcast is displayed as a horizontal bar graph in which black squares are arranged. Note that one of the square and the black square in the figure represents a band of about 1 Mbps. Therefore, in the example of FIG. 35A, the reserved bandwidth is 7 Mbps, and the required bandwidth of the current channel is 7 Mbps.

  By referring to the images shown in FIGS. 35A to 35C, the user can grasp the necessary bandwidth of the content being broadcast, and whether or not the necessary bandwidth is sufficient in the currently secured bandwidth. Can be grasped.

  Furthermore, in FIG. 35 (a), the necessary band related to two of the channel being viewed and the other channels are displayed. In the illustrated example, the maximum necessary bandwidth is displayed among the necessary bandwidths of the content being broadcast on channels other than the channel being viewed. Therefore, the user can grasp that there is a possibility that the content to be reproduced is disturbed when the channel is switched by referring to the image shown in FIG.

  Further, in FIG. 35 (b), the necessary bands related to three of the channel being viewed and the adjacent channel are displayed. The illustrated example is suitable when the user switches channels using an up button and a down button on a remote controller or the like.

  At this time, a channel for which a necessary bandwidth is not secured may be skipped. For example, assume that the currently displayed channel is channel 3 in FIG. At this time, channel 4 becomes the next channel. Furthermore, it is assumed that the necessary bandwidth of the channel 5 is secured. In such a case, when the up button is pressed, the video of channel 4 is normally displayed. However, as shown in the figure, the necessary bandwidth of channel 4 is not secured, so channel 4 is skipped and the channel is skipped. 5 images will be displayed.

  In FIG. 35 (c), the necessary bandwidth for all channels is displayed. In the figure, a symbol> is added to the channel being viewed. The illustrated example is suitable when the user switches channels with a numeric keypad on a remote controller or the like. Note that the channels for which the necessary bandwidth is not secured may be hidden on the illustrated list.

  In addition, regarding the bar graphs of FIGS. 35A to 35C, as described above, whether or not the necessary bandwidth is secured may be expressed by the color of the bar graph. Thereby, the user can grasp | ascertain rapidly whether the said required zone | band is ensured by referring the color of the said bar graph. Further, as described above, the required bandwidth and the currently secured bandwidth may be displayed together in one bar graph. In this case, there is no need to secure an area for displaying a bar graph indicating the currently secured band.

  In each of the display forms shown in FIGS. 34A to 34C and FIGS. 35A to 35C, the user inputs instruction information to the input unit 34 by operating a remote controller or the like. By doing so, it may be switchable. Also, the channel names in FIGS. 34 (a) to 34 (c) and FIGS. 35 (a) to 35 (c) may be changed to broadcast station names.

  FIG. 36 and FIG. 37 show another example in which the above-described bandwidth reservation state is displayed on the TV 20. In the example shown in the figure, when the EPG is displayed on the TV 20 in step S53 and the user selects content, the band securing state is displayed on the TV 20 together with the EPG.

  Specifically, in FIG. 36 and FIG. 37, based on the broadcast channel and broadcast time of the content included in the EPG, the title names of the currently broadcasted and scheduled broadcast content are displayed in time series for each channel. Yes. Also, the white arrow in the figure indicates the currently selected channel, and the inverted black triangle in the figure indicates the current time.

  In FIG. 36, for each content currently being broadcast, the symbol O or symbol X as the band securing state is displayed along with the title name of the content. A symbol ◯ indicates a state in which a necessary bandwidth for the corresponding content is secured, and a symbol × indicates a state in which the necessary bandwidth for the corresponding content is not secured. 36. Since the necessary bandwidth for the contents of the titles 3-1 and 5-1 is not secured by referring to the screen shown in FIG. 36, the user switches the contents from channel 1 to channel 3 or channel 5 to play back the contents. It is possible to grasp that there is a risk of disturbance.

  On the other hand, in FIG. 37, for each content currently being broadcast, the band securing state is expressed by the background color of the title name. In the example shown in the figure, the background color of the title name is displayed in green when the necessary bandwidth is secured for each of the above contents, while the background color of the title name is red when the necessary bandwidth is not secured. it's shown. Thus, the user can quickly grasp whether or not the necessary bandwidth is secured by referring to the background color of the title name in the content currently being broadcast.

  In FIG. 36, the band reservation state is indicated by symbols ○ / ×, but other symbols may be used, and icons, colors, characters such as “OK” and “NO” may be used. May be. In FIG. 37, the band securing state is represented by the background color of the title name, but the band securing state may be represented by the color of the title name character string. As described above, any means for expressing information can be used for the band securing state.

  Note that the display form shown in FIG. 36 and the display form shown in FIG. 37 may be switched by the user operating the remote controller or the like to input instruction information to the input unit 34. In addition, the image of FIG. 36 or FIG. 37 may be superimposed and displayed on a partial area of the video content being displayed. At this time, the position of the superimposed region may be changeable by the user operating the remote controller or the like to input instruction information to the input unit 34.

  In FIG. 36 and FIG. 37, the title name or channel of the content for which the necessary bandwidth is not secured among the currently broadcast content is not displayed or displayed in a different color tone (for example, displayed in a color with low luminance). It may be changed. Further, the channel may not be selected by the user.

[Embodiment 4]
Next, still another embodiment of the present invention will be described with reference to FIGS. 16 to 19 and FIGS. The content distribution system 11 of the present embodiment is different from the content distribution system 11 shown in FIGS. 12 to 15 only in the functions of the bandwidth determination unit 42 and the bandwidth notification unit 44 and the data structure of the determined bandwidth storage unit 47. Other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  In the present embodiment, the bandwidth determination unit 42 is necessary for data transmission among content scheduled to be distributed at a certain time on a certain channel and content scheduled to be distributed next on the same channel. A bandwidth determination unit that determines a bandwidth with a larger bandwidth and associates the determined bandwidth with the time, the channel, and the sufficient bandwidth as a sufficient bandwidth for viewing the channel at the time. 47, and this is repeated for each time and each channel included in the EPG.

  Then, the band notification unit 44 determines whether the sufficient band increases or decreases when the next content is continuously viewed on the currently viewed channel. When the sufficient bandwidth increases, the bandwidth notification unit 44 notifies the PLC master unit 15 of the increased sufficient bandwidth via the communication unit 33 at a time before a predetermined time from the time when the next content is switched. . On the other hand, when the sufficient bandwidth decreases, the bandwidth notification unit 44 sends the reduced sufficient bandwidth to the PLC master unit 15 via the communication unit 33 at a time after a predetermined time from the time when the next content is switched. Notice. As a result, there is an advantage that it is not necessary to reset the band secured in the PLC network 16 at the moment when the content distributed in the channel being viewed is switched.

  FIG. 16 is a diagram showing a bandwidth table determined by the bandwidth determination unit 42 and stored in the determined bandwidth storage unit 47. The bandwidth table shown in FIG. 16 is obtained from the EPG shown in FIG. 11 as follows.

  That is, first, consider a case where the user views the content AAA of the channel CH1 between 8:00 and 9:00. Here, when the user does not perform the channel switching operation, the distributed content is switched from the content AAA to the content BBB at 9:00. Therefore, when the user watches the channel CH1 by 9:00, the larger one of the band necessary for data transmission of the content AAA and the band necessary for data transmission of the content BBB is displayed. A sufficient bandwidth that is a bandwidth to be secured in the network 16 is set. Here, the 10 Mbps bandwidth of the content BBB is selected as a sufficient bandwidth.

  Next, considering the case where the content BBB of the channel CH1 is viewed between 9:00 and 9:15, data transmission is performed between the content BBB and the content CCC scheduled to be distributed from 9:15. The bandwidth of 15 Mbps of the content CCC having the larger bandwidth required for the above is selected as a sufficient bandwidth, and becomes a sufficient bandwidth when the user is viewing the channel CH1 from 9:00 to 9:15. Similarly, a sufficient bandwidth is required when the user views the channel CH1 until the last time scheduled for broadcasting by EPG. In the case where the user views channel CH1 from 11:00 to 12:00, the content scheduled to be distributed at the next time does not exist on the EPG, so the necessary bandwidth for content EEE remains unchanged. Sufficient bandwidth.

  Further, a sufficient band for viewing each channel is obtained in the same manner for the channels CH2 and CH3. In the embodiment shown in FIGS. 12 to 15, the bandwidth to be secured in the PLC network 16 is determined by the time, but in the present embodiment, the bandwidth to be secured depends on the time and the channel being viewed. Will be decided.

  Next, the flow of processing operations of the content distribution system 11 having the above configuration will be described with reference to FIGS. FIG. 17 is a flowchart showing the flow of processing in the STB 17 of the content distribution system 11 of the present embodiment. In addition, since the process of the multicast point 51 of the content delivery system 11, the EPG server 52, and the PLC main | base station 15 is the same as the process shown in FIG. 10, the description is abbreviate | omitted.

  As shown in FIG. 17, first, the related information acquisition unit 41 of the STB 17 sends an EPG including related information of content scheduled to be distributed by the IP broadcast server 50 via the communication unit 33, as in FIGS. 9 and 10. The server 52 requests and acquires the EPG, and stores (stores) the acquired EPG in the related information storage unit 46 (steps S50 and S51).

  Next, the bandwidth determination unit 42 of the STB 17 refers to the EPG stored in the related information storage unit 46 and, as described above, the bandwidth to be secured in the PLC network 16 when each channel is viewed (sufficiently) Band) is determined for each time, and the time, the channel, and the sufficient band are associated with each other and stored in the determined band storage unit 47 (step S110).

  FIG. 18 is a flowchart showing the details of the process (step S110) in which the band determining unit 42 determines the transmission band. As shown in the figure, first, channel c is set to 1 (step S130). Here, it is assumed that the contents included in the EPG are allocated to integer channel numbers starting from 1.

  Next, the time t is set to the distribution start time t0 of the content having the earliest distribution time among all the contents included in the EPG (step S131). In the example of the EPG in FIG. 10, t0 = 8: 00.

  Next, it is determined whether or not the time t has reached the distribution start time u of the content (c, u) (step S132). Here, content (c, u) represents content whose distribution start time is u in channel c. When distribution start time u has been reached (YES in step S132), sufficient bandwidth B (c, t) when channel c is viewed at time t is determined and stored in determined bandwidth storage unit 47. (Step S133). Details of step S133 will be described later.

  After step S133 or when the distribution start time has not been reached (NO in step S132), time t is advanced (step S134), and it is determined whether time t has reached the last time in the EPG ( Step S135). If time t has not reached the last time of the EPG (NO in step S135), the process returns to S132 and the above operation is repeated.

  On the other hand, if time t has reached the last time of the EPG (YES in step S135), it is determined whether channel c is the last channel in the EPG (step S136). If channel c is not the last channel (NO in step S136), channel c is incremented by 1 (step S137), the process returns to step S132, and the above operation is repeated. On the other hand, if channel c is the last channel (YES in step S136), the bandwidth determination process is terminated and the process returns to the original routine.

  The sufficient bandwidth B (c, t) at each time t of each channel c of the EPG is determined by the processing operations of steps S130 to S137 described above, and stored in the determined bandwidth storage unit 47 as a bandwidth table. In the example of FIG. 11, first, in the channel c = 1, when the time t = 8: 00, it is the distribution start time of the content AAA. Therefore, the sufficient bandwidth B (c, t) at the time t = 8: 00 is Desired. Subsequently, when the time t is advanced and the time t = 9: 00, since it is the distribution start time of the content BBB, a sufficient bandwidth B (c, t) at the time t = 9: 00 is obtained. Subsequently, when time t is advanced and time t = 9: 15, since it is the distribution start time of content CCC, sufficient bandwidth B (c, t) at time t = 9: 15 is obtained. In the same manner, a sufficient band B (c, t) in channel c = 1 up to time t = 12: 00 is obtained. Further, a sufficient band B (c, t) is obtained in the same manner for the case of channel c = 2 and channel c = 3.

  FIG. 19 shows details of the process (step S133) for determining the sufficient band B (c, t) when the channel c is viewed at time t. First, a necessary band for content (c, t) is set in band B (step S140). Here, the content (c, t) represents the content scheduled to be distributed at time t in the channel c (that is, the channel to be obtained from the bandwidth table from now on). In the example of FIG. 11, the content (c, t) when viewing the channel c = 1 at time t = 8: 00 is content AAA.

  Next, it is checked whether or not the content (c, t_next) exists (step S141). Here, the content (c, t_next) represents the content scheduled to be distributed next to the content distributed at time t in the channel c. In the previous example, the content (c, t_next) when viewing channel c = 1 at time t = 8: 00 is content BBB at time t_next = 9: 00. If the content (c, t_next) does not exist (NO in step S141), the process proceeds to step S144.

  On the other hand, if the content (c, t_next) exists (YES in step S141), the size of the bandwidth B and the required bandwidth of the content (c, t_next) are compared (step S142). If the band B is smaller, the necessary band for the content (c, t_next) is set in the band B (step S143). Thereafter, the process proceeds to step S144. On the other hand, if band B is equal to or greater than the necessary band for content (c, t_next) (NO in step S142), the process proceeds to step S144 without performing step S143.

  In step S144, the band B is determined as a sufficient band to be secured in the PLC network 16, and the process returns to the original routine.

  In the processing from step S140 to step S144, the content having the larger required bandwidth is selected as a sufficient bandwidth from the content distributed in the channel c at time t and the content scheduled to be distributed next in the same channel c. Equal to processing. In the example of FIG. 11, when time t = 8: 00 and channel c = 1, the required bandwidth of content AAA and the required bandwidth of content BBB are compared, and the bandwidth of content BBB having a larger required bandwidth value is 10 Mbps. Is required as a sufficient bandwidth. Similarly, in the case of channel CH2 at time t = 8: 30, the required bandwidth of the content GGG and the required bandwidth of the content HHH are compared, and the bandwidth 9 Mbps of the content GGG having a larger required bandwidth value is set as a sufficient bandwidth. It will be required.

  Returning to FIG. 17, as described above, when the selection instruction acquisition unit 43 of the STB 17 acquires a content selection instruction from the user (step S <b> 53), the band notification unit 44 determines a sufficient band of the current time as a determined band. The data is read from the storage unit 47 and notified to the PLC master device 15 via the communication unit 33 (step S54). Thereby, the sufficient bandwidth is secured in the PLC network 16.

  When the bandwidth notification unit 44 receives the setting result from the PLC master unit 15 via the communication unit 33 and recognizes that the bandwidth setting process has been completed, the content acquisition unit 45 is information for identifying the content selected by the user. A viewing request (join packet) with the added channel is transmitted to the multicast point 51 (step S55). Thereby, the STB 17 starts receiving the content data (step S56). The content acquisition unit 45 converts the packet data of the acquired content into a video signal that can be output to the TV, and transmits the converted video signal to the TV 20 via the output unit 35, whereby the content is reproduced and displayed on the TV 20. The user can view the content.

  In the example of FIGS. 11 and 16, when the user selects the channel CH1 at 8:00, first, the bandwidth table of the determined bandwidth storage unit 47 is referred to and secured by the PLC network 16 by 9:00. A sufficient bandwidth of 10 Mbps to be kept is acquired, notified to the PLC master device 15, and the bandwidth of the PLC network 16 is set. Thereafter, a join packet for starting viewing of the content AAA is sent to the multicast point 51, and reception of the content AAA is started in the STB 17.

  Thereafter, as shown below, when any of the three conditions (steps S111, S112, and S117) is satisfied, processing corresponding to the corresponding condition is performed.

  That is, one of the above conditions is a case where the user has instructed channel switching (YES in step S112). In this case, the content acquisition unit 45 of the STB 17 sends a leave packet that notifies the end of viewing of the content to the multicast point 51 (step S113). The multicast point 51 that has received the leave packet deletes the STB 17 from the multicast distribution destination of the content. Thereby, the transmission of the content from the multicast point 51 to the STB 17 is completed.

  Next, the bandwidth notification unit 44 refers to the bandwidth table stored in the determined bandwidth storage unit 47, and gives the PLC master unit 15 sufficient bandwidth for viewing the newly selected content (channel) at the current time. Notification is made (step S114). Receiving this notification, the PLC master device 15 starts bandwidth setting and notifies the STB 17 of the bandwidth setting result.

  Next, when receiving the notification of the band setting result, the content acquisition unit 45 of the STB 17 sends a join packet notifying the start of viewing of the newly selected content to the multicast point 51 (step S115). The multicast point 51 that has received the join packet adds the STB 17 to the multicast distribution destination of the content. Accordingly, transmission of new content from the multicast point 51 to the STB 17 is started, and the content acquisition unit 45 of the STB 17 starts receiving new content data (step S116).

  In the example of FIGS. 11 and 16, when the user switches to channel CH2 when viewing the content AAA of channel CH1 from 8:00 to 8:30, first, the end of viewing of content AAA is notified. A leave packet is sent to the multicast point 51. Then, referring to the bandwidth table of the determined bandwidth storage unit 47, a sufficient bandwidth of 13 Mbps to be secured in the PLC network 16 when the channel CH2 is viewed by 8:30 is derived. This sufficient bandwidth is notified to the PLC master device 15 and the bandwidth of the PLC network 16 is set. Thereafter, a join packet for starting viewing of the content FFF is sent to the multicast point 51, and reception of the content FFF is started in STB17.

  Another of the above conditions is a case where the sufficient bandwidth at the time when the next content is distributed in the channel being viewed changes from the currently reserved bandwidth (step S117). When the sufficient bandwidth increases, and when the time reaches a predetermined time (for example, one minute before) when the next content distribution starts (YES in step S118), or the sufficient bandwidth When the time reaches a time after a predetermined time (for example, one minute before) when the next content distribution is started (YES in step S119), the bandwidth notification unit 44 uses the PLC network. 16 informs the PLC master unit 15 of a sufficient bandwidth required by 16.

  In the example of FIGS. 11 and 16, when the content AAA is viewed on channel CH1 from 8:00 to 9:00, the sufficient bandwidth stored in the bandwidth table is increased from 10 Mbps to 15 Mbps at 9:00. Therefore, the bandwidth notification unit 44 notifies the PLC master device 15 to set a bandwidth of 15 Mbps, for example, at 8:59 one minute before the transmission of the content BBB is started. In addition, when the content CCC is viewed on the channel CH1 from 9:15 to 10:00, the sufficient bandwidth stored in the bandwidth table is reduced from 15 Mbps to 12 Mbps at 10:00. Notifies the PLC master device 15 to set a bandwidth of 12 Mbps at 10:01, for example, one minute after the transmission of the content CCC is completed.

  Bandwidth setting takes a certain amount of time because management packets are exchanged between the STB 17 and the PLC master unit 15 or the PLC master unit 15 internally changes the bandwidth allocation scheduling. End up. In addition, when the bandwidth to be secured increases, if transmission of the next content is started before the bandwidth setting is completed, transmission is performed in a state where sufficient bandwidth is not secured for transmitting the content. become. Therefore, it is desirable that the band setting is started before the transmission of new content is started, and the band setting is completed at the time when the transmission of the content is started. Therefore, in the present embodiment, when the band to be secured increases, the band setting is performed before transmission of new content is started.

  In addition, when the bandwidth to be secured decreases, if the bandwidth secured before transmission of the currently viewed content ends, a sufficient bandwidth is secured to transmit the currently viewed content. It will be transmitted in the state that is not. Therefore, it is desirable to set the bandwidth after transmission of new content is started and the reduced bandwidth becomes sufficient. Therefore, in the present embodiment, when the band to be secured decreases, the band setting is performed after transmission of new content is started.

  Also, if the content BBB is viewed on the channel CH1 from 9:00 to 9:15, the sufficient bandwidth stored in the bandwidth table does not change from 15 Mbps at 9:15. The notification of the band as described above is omitted at the time of switching. However, as described above, the band notification unit 44 may notify the PLC master unit 15 that the content to be transmitted has changed.

  In step S117, if the sufficient bandwidth at the time when the next content is distributed in the channel being viewed is the same as the currently reserved bandwidth (NO in the same step), the bandwidth notification (step S120) is omitted. is doing. Thereby, the bandwidth notification process in the STB 17 can be reduced, and the bandwidth securing process in the PLC master unit 15 can be reduced.

  The last one of the above conditions is when the user gives an instruction to end viewing of the content, for example, by turning off the TV 20 (YES in step S111). In this case, the content acquisition unit 45 of the STB 17 sends a leave packet notifying the end of content viewing to the multicast point 51 (step S121). The multicast point 51 that has received the leave packet deletes the STB 17 from the multicast distribution destination of the content. Thereby, the transmission of the content from the multicast point 51 to the STB 17 is completed. Further, the bandwidth notification unit 44 of the STB 17 notifies the PLC master device 15 to release the bandwidth secured in the PLC network 16 (step S122). Thereafter, the process ends.

  In addition, as described above, the PLC master unit 15 may not be able to secure the above-described sufficient bandwidth for the STB 17, and in this case, the STB 17 transmits the above-described bandwidth reservation state to the TV 20 for display. It is desirable to notify the user.

  FIG. 38A and FIG. 38B show an example of the band securing state displayed in the band securing state display area 60 shown in FIG. In the example shown in the figure, the symbol O or symbol X is displayed as the band securing state regarding the content of the channel currently being viewed and the content scheduled to be broadcast on the channel. Here, the symbol “◯” indicates a state where the necessary bandwidth of the corresponding content is secured, and the symbol “X” indicates a state where the necessary bandwidth is not secured. Therefore, the user can grasp whether or not the reproduction of the content that changes over time is disturbed by referring to the images shown in FIGS. 38 (a) and 38 (b).

  In FIG. 38 (a), the above-mentioned bandwidth reservation state is displayed for two contents: the content of the channel being viewed and the content scheduled to be broadcast next on the channel. Therefore, by referring to the image shown in FIG. 38A, the user can grasp whether or not the reproduction of the content to be switched next over time is disturbed.

  Further, in FIG. 38B, the above-described band securing state regarding the content of the channel being viewed and all the content scheduled to be broadcast on the channel is displayed. In the example shown in the figure, each content scheduled to be broadcast is distinguished by the broadcast start time. Therefore, the user can grasp when the reproduction of the content scheduled to start broadcasting on the channel is disturbed by referring to the image shown in FIG.

  In FIG. 38 (a) and FIG. 38 (b), the band reservation state is indicated by symbols ○ · ×, but other symbols may be used, and icons, colors, “OK”, “ Characters such as “No” may be used. Furthermore, the area to which the symbol or the like is attached may be omitted, and the band securing state may be expressed by the character string and / or background color in the character string column including “content”. For example, content that is being viewed or scheduled to be broadcast in which the necessary bandwidth is secured displays the character string in green, while the content in which the necessary bandwidth is not secured is displayed in red. As described above, any means for expressing information can be used for the band securing state.

  FIG. 39A and FIG. 39B show another example of the bandwidth securing state displayed in the bandwidth securing state display area 60 shown in FIG. In the example shown in the figure, as the band securing state, the currently secured band is displayed as a bar graph, and the necessary bandwidth of the content of the channel currently being viewed and the content scheduled to be broadcast on the channel is displayed as a bar graph. Specifically, the currently reserved bandwidth is displayed as a horizontal bar graph in which squares are arranged, and the necessary bandwidth of the content is displayed as a horizontal bar graph in which black squares are arranged. Note that one of the square and the black square in the figure represents a band of about 1 Mbps. Therefore, in the example of FIG. 39A, the reserved bandwidth is 7 Mbps, and the required bandwidth of the content being viewed is 7 Mbps.

  By referring to the images shown in FIG. 39 (a) and FIG. 39 (b), the user can grasp the necessary bandwidth of the contents and grasp whether or not the necessary bandwidth is sufficient with the currently secured bandwidth. can do.

  In FIG. 39 (a), necessary bandwidths for the content of the channel currently being viewed and the content scheduled to be broadcast next on the channel are displayed. Therefore, by referring to the image shown in FIG. 39 (a), the user grasps how much or less the necessary bandwidth of the content to be switched over with the passage of time is compared to the currently secured bandwidth. be able to.

  In FIG. 39 (b), the necessary bandwidth relating to the content of the channel being viewed and some of the content scheduled to be broadcast on the channel is displayed. Therefore, the user grasps how much the necessary bandwidth of each content scheduled to be broadcast on the channel is larger or smaller than the currently secured bandwidth by referring to the image shown in FIG. be able to.

  Note that regarding the bar graphs in FIGS. 39A and 39B, as described above, whether or not the necessary bandwidth is secured may be expressed by the color of the bar graph. Thereby, the user can grasp | ascertain rapidly whether the said required zone | band is ensured by referring the color of the said bar graph. Further, as described above, the required bandwidth and the currently secured bandwidth may be displayed together in one bar graph. In this case, it is easy to compare the currently reserved bandwidth with the required bandwidth of each content, and it is not necessary to secure an area for displaying a bar graph indicating the currently reserved bandwidth.

  In each display mode shown in FIGS. 38A, 38B, 39A, and 39B, the user inputs instruction information to the input unit 34 by operating a remote controller or the like. By doing so, it may be switchable. Also, the character strings shown in FIGS. 38 (a), 38 (b), 39 (a), and 39 (b) may be changed to content title names, program names, and the like.

  FIG. 40 and FIG. 41 show another example in which the band securing state is displayed on the TV 20. In the example shown in the figure, when the EPG is displayed on the TV 20 in step S53 and the user selects content, the band securing state is displayed on the TV 20 together with the EPG.

  Specifically, in FIG. 40 and FIG. 41, based on the broadcast channel and broadcast time of the content included in the EPG, the title names of the content currently being broadcast and scheduled to be broadcast are displayed in time series for each channel. Yes. Also, the white arrow in the figure indicates the currently selected channel, and the inverted black triangle in the figure indicates the current time.

  In FIG. 40, with respect to each content in the currently selected channel, a symbol “◯” or “symbol ×” as the band securing state is displayed along with the title name of the content. A symbol ◯ indicates a state in which a necessary bandwidth for the corresponding content is secured, and a symbol × indicates a state in which the necessary bandwidth for the corresponding content is not secured. The user refers to the screen shown in FIG. 40, so that the necessary bandwidth for the content of the title 4-4 is not secured, so the content of the title 4-4 broadcast from 20:30 on the selected channel. It is possible to grasp that there is a risk of disturbance.

  On the other hand, in FIG. 41, the band securing state is expressed by the background color of the title name for each content in the currently selected channel. In the example shown in the figure, the background color of the title name is displayed in green when the necessary bandwidth is secured for each of the above contents, while the background color of the title name is red when the necessary bandwidth is not secured. it's shown. Thus, the user can quickly grasp whether or not the necessary bandwidth is secured by referring to the background color.

  In FIG. 40, the band reservation state is indicated by symbols ○ / ×, but other symbols may be used, and icons, colors, characters such as “OK” and “NO” may be used. May be. In FIG. 41, the band securing state is represented by the background color of the title name, but the band securing state may be represented by the color of the title name character string. As described above, any means for expressing information can be used for the band securing state.

  In FIG. 40 and FIG. 41, when the user switches channels, the above-described band securing state is displayed for the channel after switching. Also, the display form shown in FIG. 40 and the display form shown in FIG. 41 may be switched when the user inputs instruction information to the input unit 34 by operating a remote controller or the like. In addition, the image of FIG. 40 or 41 may be superimposed on a partial area of the video content being displayed. At this time, the position of the superimposed region may be changeable by the user operating the remote controller or the like to input instruction information to the input unit 34.

  40 and 41, the title name of the content for which the necessary bandwidth is not secured for the currently selected channel is changed to non-display or display with a different color tone (for example, display with a low luminance color). Also good.

[Embodiment 5]
Next, still another embodiment of the present invention will be described with reference to FIGS. The content distribution system 11 of the present embodiment is a combination of the content distribution system 11 shown in FIGS. 12 to 15 and the content distribution system 11 shown in FIGS. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  In the present embodiment, the bandwidth determination unit 42 includes a required bandwidth of content scheduled to be distributed at a certain time and a required bandwidth of content scheduled to be distributed next in the channel being viewed at the above time. The maximum bandwidth is determined, and the determined bandwidth is stored in the determined bandwidth storage unit 47 as a bandwidth table in which the time, the channel, and the sufficient bandwidth are associated with each other as a sufficient bandwidth for viewing the channel at the time. This is repeated for all times and all channels included in the EPG.

  Then, when the content that can be viewed on any channel changes while viewing the content, the bandwidth notification unit 44 allocates a sufficient bandwidth to be secured in the PLC network 16 every time the PLC master unit 15 is notified. Further, the band notification unit 44 determines whether the sufficient band increases or decreases when the next content is continuously viewed on the currently viewed channel. When the sufficient bandwidth increases, the bandwidth notification unit 44 notifies the PLC master unit 15 of the increased sufficient bandwidth via the communication unit 33 at a time before a predetermined time from the time when the next content is switched. . On the other hand, when the sufficient bandwidth decreases, the bandwidth notification unit 44 sends the reduced sufficient bandwidth to the PLC master unit 15 via the communication unit 33 at a time after a predetermined time from the time when the next content is switched. Notice.

  Thereby, when the user is viewing the content of a certain channel, when switching to the content of another channel, a sufficient band to be secured in the PLC network 16 is set in advance, so that high-speed content switching Is possible. Furthermore, there is an advantage that it is not necessary to reset the band secured in the PLC network 16 at the moment when the content distributed in the channel being viewed is switched.

  FIG. 20 is a diagram showing a bandwidth table determined by the bandwidth determination unit 42 and stored in the determined bandwidth storage unit 47. The bandwidth table shown in FIG. 20 is obtained from the EPG shown in FIG. 11 as follows.

  That is, first, consider a case where the user views the content AAA of channel CH1 between 8:00 and 8:30. Here, when the user performs a channel switching operation, the contents that can be selected are the content FFF of the channel CH2 and the content III of the channel CH3. On the other hand, when the user does not perform the channel switching operation, the distribution of the content BBB is started instead of the content AAA at 9:00 on the channel CH1.

  Therefore, in the present embodiment, the band having the largest band is selected from the bands necessary for data transmission of the contents AAA, the contents FFF, the contents III, and the contents BBB, and the time is until 8:30. The bandwidth is stored in advance in the determined bandwidth storage unit 47 as a sufficient bandwidth when viewing the channel CH1. In the example of FIG. 11, the required bandwidth of 13 Mbps corresponding to the content FFF is selected as a sufficient bandwidth.

  Similarly, when viewing the content AAA of the channel CH1 from 8:30 to 9:00, the content AAA, the content GGG, and the content III distributed on each channel at the same time and the channel CH1 are the next. Among the content BBBs scheduled to be distributed, the one with the largest necessary bandwidth, that is, the necessary bandwidth of 10 Mbps corresponding to the content BBB is selected as a sufficient bandwidth.

  Considering the case where the content GGG of the channel CH2 is viewed from 9:15 to 10:00, the content CCC, the content GGG, and the content III distributed on each channel at the same time and the channel CH2 are next. Among the contents HHH scheduled to be distributed, the one having the largest necessary bandwidth, that is, the necessary bandwidth of 15 Mbps corresponding to the content CCC is selected as a sufficient bandwidth.

  Considering the case where the content KKK of the channel CH3 is viewed from 11:00 to 12:00, the most necessary bandwidth among the content EEE, the content HHH, and the content KKK distributed on each channel at the same time. That is, the required bandwidth of 12 Mbps corresponding to the content EEE is selected as a sufficient bandwidth. In this example, since there is no content scheduled to be distributed next on channel CH3, the necessary bandwidth is obtained by focusing only on the content distributed at the same time.

  By obtaining a sufficient bandwidth at each time for each channel in the same procedure as described above, it is stored in the determined bandwidth storage unit 47 as a bandwidth table as shown in FIG. In the embodiment shown in FIGS. 12 to 15, the bandwidth to be secured in the PLC network 16 is determined by the time, but in the present embodiment, the bandwidth to be secured depends on the time and the channel being viewed. Will be decided.

  Next, the flow of the processing operation of the content distribution system 11 having the above configuration will be described with reference to FIGS. FIG. 21 is a flowchart showing the flow of processing in the STB 17 of the content distribution system 11 of this embodiment. In addition, since the process of the multicast point 51 of the content delivery system 11, the EPG server 52, and the PLC main | base station 15 is the same as the process shown in FIG. 10, the description is abbreviate | omitted.

  As shown in FIG. 21, first, the related information acquisition unit 41 of the STB 17 sends an EPG including related information of content scheduled to be distributed by the IP broadcast server 50 via the communication unit 33, as in FIGS. 9 and 10. The server 52 requests and acquires the EPG, and stores (stores) the acquired EPG in the related information storage unit 46 (steps S50 and S51).

  Next, the bandwidth determination unit 42 of the STB 17 refers to the EPG stored in the related information storage unit 46 and, as described above, the bandwidth to be secured in the PLC network 16 when each channel is viewed (sufficiently) Band) is determined for each time, and the time, the channel, and the sufficient band are associated with each other and stored in the determined band storage unit 47 (step S150).

  FIG. 22 is a flowchart showing details of the process (step S150) in which the band determining unit 42 determines the transmission band. As shown in the figure, first, the time t is set to the distribution start time t0 of the content having the earliest distribution time among all the contents included in the EPG (step S170). In the example of FIG. 11, t0 is 8:00. Next, channel i is set to 1 (step S171). Here, it is assumed that the content included in the EPG is assigned to an integer channel number starting from 1.

  Next, it is determined whether or not the time t has reached the distribution start time u of the content (i, u) (step S172). Here, the content (i, u) represents the content whose distribution is started from the time u in the channel i.

  If time t has not reached the distribution start time u of content (i, u) (NO in step S172), it is determined whether channel i is the last channel number in the EPG (step S173). If it is not the last channel number (NO in step S173), after channel i is incremented by 1 (step S174), the process returns to step S172 and the above operation is repeated. On the other hand, if it is the last channel number (YES in step S173), it is determined that there is no content whose time t has reached the distribution start time u, and the process proceeds to step S179.

  On the other hand, when the time t reaches the distribution start time u of the content (i, u) (YES in step S172), the channel c is set to 1 (step S175), and then the maximum required bandwidth at the time t is reached. The sufficient bandwidth B (t) is determined, and the time t, the channel c, and the sufficient bandwidth B (t) are associated with each other and stored in the determined bandwidth storage unit 47 (step S176). Details of step S176 will be described later.

  Next, it is determined whether or not the channel c is the last channel number in the EPG (step S177). If it is not the last channel number (NO in step S177), after channel c is incremented by 1 (step S178), the process returns to step S176 and the above operation is repeated. On the other hand, in the case of the last channel number (YES in step S177), it is determined that a sufficient band of each channel at time t has been determined, and the process proceeds to step S179.

  In step S179, time t is advanced by a predetermined time. Next, it is determined whether or not the time t has reached the last time included in the EPG (step S180). If time t has not reached the last time (NO in step S180), the process returns to step S171 and the above processing operation is repeated. On the other hand, when time t has reached the last time (YES in step S180), the bandwidth determination process is terminated and the process returns to the original routine.

  The sufficient bandwidth B (c, t) at each time t of each channel c of the EPG is determined by the processing operations of steps S170 to S180 described above, and stored in the determined bandwidth storage unit 47 as a bandwidth table. In the example of FIG. 11, first, when the time t = 8: 00, it is the distribution start time of the content AAA of the channel i = 1, so the channels c = 1, c = 2, c at the time t = 8: 00. A sufficient bandwidth B (c, t) at = 3 is obtained. Subsequently, when t is advanced and t = 8: 30, since it is the distribution start time of the content GGG of channel i = 2, channels c = 1, c = 2, c = 3 at time t = 8: 30 A sufficient bandwidth B (c, t) is obtained. Subsequently, when t is advanced and t = 9: 00, since it is the distribution start time of the content BBB of channel i = 1, channels c = 1, c = 2, c = at time t = 9: 00. A sufficient bandwidth B (t) at 3 is obtained. In the same manner, a sufficient band B (c, t) in each channel c until time t = 12: 00 is obtained.

  FIG. 23 shows details of the process (step S176) for determining the sufficient bandwidth B (c, t). As shown in the figure, first, the bandwidth B to be secured in the PLC network 16 is initialized to 0 Mbps and the counter i is initialized to 1 (step S190). Next, it is determined whether or not the necessary bandwidth for the content (i, t) is larger than the bandwidth B (step S191). If it is larger, the necessary bandwidth for the content (i, t) is present in the bandwidth B. It is set (step S192), and then the process proceeds to step S193.

  Here, content (i, t) represents content scheduled to be distributed at time t on channel i. In the example of FIG. 11, when the time t = 8: 30, the content (i, t) can be selected as the content AAA scheduled to be distributed from 8:00 to 9:00 on the channel CH1, Content GGG scheduled to be distributed from 8:30 to 11:00 on channel CH2 and content III scheduled to be distributed from 8:00 to 10:10 on channel CH3.

  Next, in step S193, it is determined whether the content (i + 1, t) exists, that is, whether the EPG corresponding to the content (i + 1, t) is stored in the related information storage unit 46. If stored (YES in step S193), after the counter i is incremented by 1 (step S194), the process returns to step S191 to repeat the above operation. On the other hand, if it is not stored (NO in step S193), it is checked whether content (c, t_next) exists (step S195). Here, the content (c, t_next) represents the content scheduled to be distributed next to the content distributed at time t in the channel c. In the example of FIG. 11, the content (c, t_next) when viewing the channel c = 1 at time t = 8: 30 is content BBB at time t_next = 9: 00. If the content (c, t_next) does not exist (NO in step S141), the process proceeds to step S198.

  On the other hand, if the content (c, t_next) exists (YES in step S195), the size of the bandwidth B and the required bandwidth of the content (c, t_next) are compared (step S196). If the band B is smaller, the necessary band for the content (c, t_next) is set in the band B (step S197). Thereafter, the process proceeds to step S144. On the other hand, if band B is equal to or greater than the necessary band for content (c, t_next) (NO in step S196), the process proceeds to step S198 without performing step S197.

  In step S198, the band B is determined as a sufficient band to be secured in the PLC network 16, and the process returns to the original routine.

  The processing of steps S190 to S198 is equivalent to the processing of selecting the one having the larger required bandwidth among the content distributed in each channel at time t and the content scheduled to be distributed next in a certain channel c. . In the example of FIG. 11, when the time t = 8: 30 and the channel c = 1, the contents AAA, the content GGG, the content III, and the content BBB are compared in size, and the content having the largest necessary bandwidth value is compared. The BBB bandwidth of 13 Mbps is required as a sufficient bandwidth. Similarly, in the case of time t = 10: 00 and channel c = 2, the size of the required bandwidth of the content DDD, content GGG, content III, and content HHH is compared, and the content GGG having the largest required bandwidth value is compared. A bandwidth of 9 Mbps is required as a sufficient bandwidth.

  Returning to FIG. 21, as described above, when the selection instruction acquisition unit 43 of the STB 17 acquires a content selection instruction from the user (step S <b> 53), the band notification unit 44 determines the content selected at the current time. The sufficient bandwidth of the channel is read from the determined bandwidth storage unit 47 and notified to the PLC master unit 15 via the communication unit 33 (step S54). Thereby, the sufficient bandwidth is secured in the PLC network 16.

  When the bandwidth notification unit 44 receives the setting result from the PLC master unit 15 via the communication unit 33 and recognizes that the bandwidth setting process has been completed, the content acquisition unit 45 is information for identifying the content selected by the user. A viewing request (join packet) with the added channel is transmitted to the multicast point 51 (step S55). Thereby, the STB 17 starts receiving the content data (step S56). The content acquisition unit 45 transmits the acquired content data to the TV 20 via the output unit 35, whereby the content is reproduced and displayed, and the user can view the content.

  In the example of FIGS. 11 and 20, when the user selects channel CH1 at 8:00, first, the bandwidth table of the determined bandwidth storage unit 47 is referred to, and the PLC network 16 from 8:00 to 8:30 is referred to. A sufficient bandwidth of 13 Mbps to be secured is acquired, notified to the PLC master device 15, and the bandwidth of the PLC network 16 is set. Thereafter, a join packet for starting viewing of the content AAA is sent to the multicast point 51, and reception of the content AAA is started in the STB 17.

  Thereafter, as shown below, when one of the four conditions (steps S151, S152, S156, and S157) is satisfied, processing corresponding to the corresponding condition is performed.

  That is, one of the above conditions is a case where the user has instructed channel switching (YES in step S152). In this case, the content acquisition unit 45 of the STB 17 sends a leave packet that notifies the end of viewing of the content to the multicast point 51 (step S153). The multicast point 51 that has received the leave packet deletes the STB 17 from the multicast distribution destination of the content. Thereby, the transmission of the content from the multicast point 51 to the STB 17 is completed.

  Next, the content acquisition unit 45 of the STB 17 sends a join packet that notifies the start of viewing of the newly selected content to the multicast point 51 (step S154). The multicast point 51 that has received the join packet adds the STB 17 to the multicast distribution destination of the content. As a result, transmission of new content from the multicast point 51 to the STB 17 is started, and the content acquisition unit 45 of the STB 17 starts receiving new content data (step S155).

  Thereafter, the bandwidth notification unit 44 refers to the bandwidth table stored in the determined bandwidth storage unit 47 and notifies the PLC master unit 15 of a sufficient bandwidth for viewing the content (channel) newly selected at the current time. (Step S114). Receiving this notification, the PLC master device 15 starts bandwidth setting and notifies the STB 17 of the bandwidth setting result.

  In the example of FIGS. 11 and 20, when the user switches to channel CH2 while viewing the content AAA of channel CH1 from 8:30 to 9:00, first, the end of viewing of content AAA is notified. A leave packet is sent to the multicast point 51. Next, a join packet for starting viewing of the content GGG is sent to the multicast point 51, and reception of the content GGG is started in STB17. Then, referring to the bandwidth table of the determined bandwidth storage unit 47, a sufficient bandwidth 9 Mbps to be secured in the PLC network 16 when the channel CH2 is viewed from 8:30 to 9:00 is derived. This sufficient bandwidth is notified to the PLC master device 15 and the bandwidth of the PLC network 16 is set.

  On the other hand, another condition is when the time when the bandwidth to be secured in the PLC network 16 is changed by referring to the bandwidth table of the determined bandwidth storage unit 47 (YES in step S156). In this case, the bandwidth notification unit 44 notifies the PLC master device 15 of a new sufficient bandwidth (step S160). In the example of FIGS. 11 and 20, when the content AAA is viewed on the channel CH1 from 8:00 to 9:00, the sufficient bandwidth stored in the determined bandwidth storage unit 47 at 8:30 is from 13 Mbps. Since the bandwidth changes to 10 Mbps, the bandwidth notification unit 44 notifies the PLC master unit 15 to set the required bandwidth of the network to 10 Mbps at 8:30.

  Further, another of the above conditions is a case where the sufficient bandwidth at the time when the next content is distributed in the channel being viewed changes from the currently reserved bandwidth (step S157). When the sufficient bandwidth is increased and the time reaches a predetermined time (for example, one minute before) when the next content distribution starts (YES in step S158), or the sufficient bandwidth When the time reaches a time after a predetermined time (for example, one minute before) when the next content distribution is started (YES in step S159), the bandwidth notification unit 44 uses the PLC network. 16 informs the PLC master unit 15 of a sufficient bandwidth required by 16.

  In the example of FIG. 11 and FIG. 20, when the content AAA is viewed on the channel CH1 from 8:30 to 9:00, the sufficient bandwidth stored in the bandwidth table increases from 10 Mbps to 15 Mbps at 9:00. Therefore, the bandwidth notification unit 44 notifies the PLC master device 15 to set the bandwidth of the PLC network 16 to 15 Mbps, for example, at 8:59, one minute before starting to view the content BBB.

  In addition, when the content CCC is viewed on the channel CH1 from 9:15 to 10:00, the sufficient bandwidth stored in the bandwidth table is reduced from 15 Mbps to 12 Mbps at 10:00. Notifies the PLC master unit 15 to set the bandwidth of the PLC network 16 to 12 Mbps, for example, at 10:01, one minute after the start of viewing the content DDD.

  In addition, when viewing the content BBB on the channel CH1 from 9:00 to 9:15, the necessary bandwidth stored in the bandwidth table does not change from 15 Mbps at 9:15. The notification of the band as described above can be omitted at the time of switching. However, as described above, the bandwidth notification unit 44 may notify the PLC master device 15 that the content to be transmitted has changed.

  The last one of the above conditions is when the user gives an instruction to end viewing of the content, for example, by turning off the TV 20 (YES in step S151). In this case, the content acquisition unit 45 of the STB 17 sends a leave packet notifying the end of content viewing to the multicast point 51 (step S161). The multicast point 51 that has received the leave packet deletes the STB 17 from the multicast distribution destination of the content. Thereby, the transmission of the content from the multicast point 51 to the STB 17 is completed. Further, the bandwidth notification unit 44 of the STB 17 notifies the PLC master device 15 to release the bandwidth secured in the PLC network 16 (step S162). Thereafter, the process ends.

  In addition, as described above, the PLC master unit 15 may not be able to secure the above-described sufficient bandwidth for the STB 17, and in this case, the STB 17 transmits the above-described bandwidth reservation state to the TV 20 for display. It is desirable to notify the user. As an example of the image displayed as the band secured state, an image obtained by combining any one of FIGS. 34A to 34C and one of FIGS. 38A and 38B, FIG. An image combining any one of (a) to FIG. 35 (c) and one of FIG. 39 (a) and FIG. 39 (b), an image combining FIG. 36 and FIG. 40, FIG. 37 and FIG. Combined images, etc. are listed.

  Note that when FIG. 36 and FIG. 40 are combined, and when FIG. 37 and FIG. 41 are combined, the above-described bandwidth reservation state is displayed for all titles regardless of the currently selected channel and the current time. As a matter of course, the above-described band securing state related to the selected channel may be displayed with priority. In addition, the band securing states may be displayed in order from the closest to the selected channel.

  For example, in the case of FIG. 41, since the currently selected channel is channel 4, the background color is selected in the order of title 4-1, title 4-2, title 4-3, and title 4-4 in accordance with the band secured state. To change. Further, for the channels 3 and 5 adjacent to the channel being selected, the band securing state of each title is determined, and then the background color of each title is changed according to the determined band securing state. After that, the background color is changed by determining the band securing state of each title in the order from the closest channel to the selected channel.

  Similarly, the band securing states may be displayed in order from the current time. For example, in the case of FIG. 41, the background color is set in accordance with the band securing state in the order of title 4-1, title 3-1, title 5-1, title 2-1, and title 1-1, which are currently broadcast contents. To change. In this case as well, the background color may be changed in the order closer to the channel being selected, as described above.

  Furthermore, the background color of the title of the content is changed according to the band securing state in order of the broadcast start time closest to the current time among the content broadcast next in each channel. For example, in the case of FIG. 41, the background color is changed in the order of title 4-2, title 1-2, title 3-2, and title 4-3.

  By displaying in this way, it is possible to confirm the above-described bandwidth reservation state for content that is likely to be selected by the user. Therefore, even when it takes time to confirm the bandwidth reservation state of all the contents, the user can quickly confirm necessary information.

[Embodiment 6]
Next, still another embodiment of the present invention will be described with reference to FIGS. The content distribution system 11 of the present embodiment is different from the content distribution system 11 shown in FIGS. 12 to 15 only in the functions of the bandwidth determination unit 42 and the bandwidth notification unit 44 and the data structure of the determined bandwidth storage unit 47. Other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  By the way, in the multicast of IP broadcasting, when switching from viewing of one content to viewing of another content, the distribution of the stream data of the previous content does not end immediately, so both the content streams before and after switching A situation occurs in which data flows on the PLC network 16.

  Therefore, in this embodiment, the bandwidth determination unit 42 has the maximum bandwidth necessary for data transmission of content being viewed and the bandwidth necessary for data transmission among the content distributed on other channels at the same time. The bandwidth obtained by adding the bandwidth and the bandwidth is stored in the determined bandwidth storage unit 47 as a bandwidth table in which the time, the channel, and the sufficient bandwidth are associated with each other as a sufficient bandwidth for viewing the channel at the time. Is repeated for all times and channels included in the EPG.

  Then, the bandwidth notification unit 44 notifies the PLC master unit 15 of a sufficient bandwidth to be secured in the PLC network 16 every time the content is switched by channel switching. Further, when the time at which the sufficient bandwidth stored in the determined bandwidth storage unit 47 changes is reached, the bandwidth notification unit 44 notifies the PLC master unit 15 of the changed sufficient bandwidth via the communication unit 33. .

  As a result, even when a situation occurs in which data of both contents before and after switching flows on the PLC network 16 simultaneously when the contents are switched, the data can be received without any disturbance.

  FIG. 24 is a diagram showing a bandwidth table determined by the bandwidth determination unit 42 and stored in the determined bandwidth storage unit 47. The bandwidth table shown in FIG. 24 is obtained from the EPG shown in FIG. 11 as follows.

  That is, consider a case where the user views the content AAA of channel CH1 between 8:00 and 8:30. Here, when the channel is switched by a user operation, the contents that can be selected are the content FFF of the channel CH2 and the content III of the channel CH3. Here, when the necessary bands of the content FFF and the content III are compared, the necessary band of the content FFF is larger.

  Therefore, if the bandwidth of 18 Mbps, which is the sum of the required bandwidth of content AAA 5 Mbps and the required bandwidth of content FFF 13 Mbps, is secured in the PLC network 16, when switching from content AAA to content FFF, and from content AAA to content III In either case of switching, even if both contents before and after switching flow simultaneously, data can be received without any disturbance. Therefore, a sufficient bandwidth for viewing channel CH1 from 8:00 to 8:30 is stored in the bandwidth table as 18 Mbps.

  Similarly, when the content FFF of the channel CH2 is viewed from 8:00 to 8:30, the required bandwidth of the content FFF is 13 Mbps, and the content AAA and the content III have the required bandwidth. A bandwidth of 21 Mbps, which is a sum of the required bandwidth of 8 Mbps for the large content III, may be secured in the PLC network 16. Also, considering the case where the content III of the channel CH3 is viewed from 9:15 to 10:00, content having a large required bandwidth among the required bandwidth 8 Mbps of the content III and the content CCC and the content GGG A bandwidth of 23 Mbps, which is a sum of the required bandwidth of CCC of 15 Mbps, may be secured in the PLC network 16.

  A sufficient bandwidth at each time of each channel is obtained by the same procedure as described above, and is stored in the determined bandwidth storage unit 47 as a bandwidth table as shown in FIG. In the embodiment shown in FIGS. 12 to 15, the bandwidth to be secured in the PLC network 16 is determined by the time, but in the present embodiment, the bandwidth to be secured depends on the time and the channel being viewed. Will be decided.

  Next, the flow of the processing operation of the content distribution system 11 having the above configuration will be described with reference to FIGS. FIG. 25 is a flowchart showing the flow of processing in the STB 17 of the content distribution system 11 of this embodiment. In addition, since the process of the multicast point 51 of the content delivery system 11, the EPG server 52, and the PLC main | base station 15 is the same as the process shown in FIG. 10, the description is abbreviate | omitted.

  As shown in FIG. 25, first, the related information acquisition unit 41 of the STB 17 sends an EPG including related information of content scheduled to be distributed by the IP broadcast server 50 via the communication unit 33, as in FIGS. The server 52 requests and acquires the EPG, and stores (stores) the acquired EPG in the related information storage unit 46 (steps S50 and S51).

  Next, the bandwidth determination unit 42 of the STB 17 refers to the EPG stored in the related information storage unit 46 and, as described above, the bandwidth to be secured in the PLC network 16 when each channel is viewed (sufficiently) Band) is determined for each time, and the time, the channel, and the sufficient band are associated with each other and stored in the determined band storage unit 47 (step S200).

  FIG. 26 is a flowchart showing details of the process (step S200) in which the band determining unit 42 determines the transmission band. As shown in the figure, first, a necessary band for content (c, t) is set in the band B1 (step S210). Here, the content (c, t) represents the content distributed at time t in the channel c (that is, the channel to be obtained from the bandwidth table from now on).

  Next, the band B2 is initialized to 0 Mbps and the channel i is initialized to 1 (step S211). Next, it is determined whether channel i and channel c are equal (step S212). If channel i is equal to channel c (YES in step S212), the process proceeds to step S215.

  On the other hand, if channel i and channel c are not equal (NO in step S212), the band sizes of band B2 and content (i, t) are compared (step S213). Here, content (i, t) represents content scheduled to be distributed at time t on channel i.

  In the example of FIG. 11, when the time t = 8: 30, the content (i, t) can be selected as the content AAA scheduled to be distributed from 8:00 to 9:00 on the channel CH1. Content GGG scheduled to be distributed from 8:30 to 11:00 on channel CH2 and content III scheduled to be distributed from 8:00 to 10:10 on channel CH3.

  If band B2 is greater than or equal to the necessary band for content (i, t) (NO in step S213), the process proceeds to step S215. On the other hand, when band B2 is smaller than the necessary band for content (i, t) (YES in step S213), the necessary band for content (i, t) is set in band B2 (step S214), and then to step S215. move on.

  In step S215, it is checked whether content (i + 1, t) exists. If content (i + 1, t) exists (YES in step S215), channel i is incremented by one (step S216), and then the process returns to step S212. On the other hand, when content (i + 1, t) does not exist (NO in step S215), the sum of band B1 and band B2 is set as sufficient band B (step S217), and band B is secured by PLC network 16 The bandwidth is determined (step S218). Thereafter, the bandwidth determination process is terminated, and the process returns to the original routine.

  In the processing of steps S210 to S218, the necessary bandwidth of the content of the channel being viewed is combined with the maximum bandwidth necessary for data transmission among the content distributed on other channels at the same time. Equivalent to the process of finding things. In the example of FIG. 24, when time t = 8: 00 and channel c = 1, a band of 18 Mbps is determined by adding a band of 5 Mbps corresponding to the content AAA and a band of 13 Mbps corresponding to the content FFF. Will be. Similarly, when time t = 9: 15 and channel c = 3, a band of 23 Mbps is determined by adding the band of 8 Mbps corresponding to content III and the band of 15 Mbps corresponding to content CCC. Become.

  Returning to FIG. 25, as described above, when the selection instruction acquisition unit 43 of the STB 17 acquires a content selection instruction from the user (step S <b> 53), the band notification unit 44 determines the content selected at the current time. The sufficient bandwidth of the channel is read from the determined bandwidth storage unit 47 and notified to the PLC master unit 15 via the communication unit 33 (step S54). Thereby, the sufficient bandwidth is secured in the PLC network 16.

  When the bandwidth notification unit 44 receives the setting result from the PLC master unit 15 via the communication unit 33 and recognizes that the bandwidth setting process has been completed, the content acquisition unit 45 is information for identifying the content selected by the user. A viewing request (join packet) with the added channel is transmitted to the multicast point 51 (step S55). Thereby, the STB 17 starts receiving the content data (step S56). The content acquisition unit 45 transmits the acquired content data to the TV 20 via the output unit 35, whereby the content is reproduced and displayed, and the user can view the content.

  In the example of FIGS. 11 and 24, when the user selects the channel CH1 at 8:00, the bandwidth table is first referred to, and the bandwidth 18 Mbps to be secured in the network from 8:00 to 8:30 is set. Obtained and notified to the PLC master unit 15, the bandwidth of the PLC network 16 is set. Thereafter, a join packet for starting viewing of the content AAA is sent to the multicast point 51, and reception of the content AAA is started in the STB 17.

  Thereafter, as shown below, when any of the three conditions (steps S201, S202, and S206) is satisfied, processing corresponding to the corresponding condition is performed.

  That is, one of the above conditions is when the time when the bandwidth to be secured in the PLC network 16 changes is reached with reference to the bandwidth table stored in the determined bandwidth storage unit 47 (YES in step S206). . In this case, the bandwidth notification unit 44 notifies the PLC master device 15 of a new sufficient bandwidth (step S207). In the example of FIG. 11 and FIG. 24, when the content AAA is viewed on the channel CH1 from 8:00 to 9:00, the sufficient bandwidth stored in the bandwidth table changes from 18 Mbps to 14 Mbps at 8:30. Therefore, the bandwidth notification unit 44 notifies the PLC master device 15 to set the bandwidth of the PLC network 16 to 14 Mbps at 8:30.

  Another of the above conditions is a case where the user has instructed channel switching (YES in step S202). In this case, the content acquisition unit 45 of the STB 17 sends a leave packet notifying the end of content viewing to the multicast point 51 (step S203). The multicast point 51 that has received the leave packet deletes the STB 17 from the multicast distribution destination of the content. Thereby, the transmission of the content from the multicast point 51 to the STB 17 is completed.

  Next, the content acquisition unit 45 of the STB 17 sends a join packet that notifies the start of viewing of the newly selected content to the multicast point 51 (step S205). The multicast point 51 that has received the join packet adds the STB 17 to the multicast distribution destination of the content. Thus, transmission of new content from the multicast point 51 to the STB 17 is started, and the content acquisition unit 45 of the STB 17 starts receiving new content data (step S205).

  Thereafter, the bandwidth notification unit 44 refers to the bandwidth table stored in the determined bandwidth storage unit 47 and notifies the PLC master unit 15 of a sufficient bandwidth for viewing the content (channel) newly selected at the current time. (Step S207). Receiving this notification, the PLC master device 15 starts bandwidth setting and notifies the STB 17 of the bandwidth setting result.

  In the example of FIGS. 11 and 24, when the user switches to the channel CH2 when viewing the content AAA of the channel CH1 from 8:00 to 8:30, first, the leaf that notifies the end of the viewing of the content AAA is notified. The packet is sent to the multicast point 51, and subsequently, a join packet for starting viewing of the content FFF is sent to the multicast point 51, and reception of the content FFF is started at STB17. Then, when the channel table is referred to and the channel CH2 is viewed from 8:00 to 8:30, a bandwidth of 21 Mbps to be secured in the PLC network 16 is derived, notified to the PLC master unit 15, and transmitted to the PLC network 16. Band is set.

  The last one of the above conditions is when the user gives an instruction to end the viewing of the content, for example, by turning off the TV 20 (YES in step S201). In this case, the content acquisition unit 45 of the STB 17 sends a leave packet that notifies the end of viewing of the content to the multicast point 51 (step S208). The multicast point 51 that has received the leave packet deletes the STB 17 from the multicast distribution destination of the content. Thereby, the transmission of the content from the multicast point 51 to the STB 17 is completed. Further, the bandwidth notification unit 44 of the STB 17 notifies the PLC master device 15 to release the bandwidth secured in the PLC network 16 (step S209). Thereafter, the process ends.

[Embodiment 7]
Next, still another embodiment of the present invention will be described with reference to FIG. The content distribution system 11 of the present embodiment is different from the content distribution system 11 shown in FIGS. 16 to 19 only in the functions of the bandwidth determination unit 42 and the bandwidth notification unit 44 and the data structure of the determined bandwidth storage unit 47. Other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  In the present embodiment, the bandwidth determination unit 42 stores the EPG as shown in FIG. 11 in the determined bandwidth storage unit 47 as it is as a bandwidth table. Then, the band notification unit 44 determines whether the sufficient band increases or decreases when the next content is continuously viewed on the currently viewed channel. When the sufficient bandwidth increases, the bandwidth notification unit 44 sends the increased sufficient bandwidth to the PLC master unit via the communication unit 33 at a time before a predetermined time from the time when the next content distribution is started. 15 is notified. As a result, since the bandwidth necessary for receiving the next content is secured at the delivery start time of the next content, the next content can be received without delay from the delivery start time. . As a result, it is possible to prevent the reproduced video of the next content from being disturbed.

  On the other hand, when the sufficient bandwidth decreases, the bandwidth notification unit 44 sends the reduced sufficient bandwidth to the PLC parent via the communication unit 33 at a time after a predetermined time from the time when the distribution of the content being viewed ends. The machine 15 is notified. As a result, after the distribution end time of the content being viewed, the bandwidth required for receiving the content being viewed is changed to the bandwidth necessary for receiving the next content. Therefore, the content being viewed can be received without delay until the distribution end time, and the next content can be reliably received without delay. As a result, it is possible to prevent the playback video of the content being viewed from being disturbed and to prevent the playback video of the next content from being disturbed.

  FIG. 28 is a flowchart showing the flow of processing in the STB 17 of the content distribution system 11 of this embodiment. The process shown in the figure differs from the process shown in FIG. 17 in that step S110 is omitted and steps S123 and S124 are performed instead of steps S118 and S119, and the other processes are the same. is there.

  In step S117, the necessary bandwidth for viewing the next content in the channel being viewed, that is, the bit rate of the content to be distributed next increases from the currently reserved bandwidth, and When it reaches a predetermined time (for example, one minute before) when the distribution is started (YES in step S123), the bandwidth notification unit 44 sets the bit rate (required bandwidth) of the next content to the PLC master unit 15. Notification is made (step S120).

  Also, in step S117, a predetermined time at which the distribution of the currently viewed content ends when the bit rate of the content to be distributed next on the currently viewed channel decreases from the currently reserved band. When it reaches later (for example, one minute later) (YES in step S124), the bandwidth notification unit 44 notifies the PLC master unit 15 of the bit rate (required bandwidth) of the next content (step S120).

  In the example of FIG. 11, when viewing the channel CH1, the distribution of the content AAA is completed at 9:00 and the distribution of the content BBB is started. At this time, since the bit rate increases from 5 Mbps to 10 Mbps, the bandwidth notification unit 44 sets the bandwidth of 10 Mbps at 8:59, for example, one minute before the distribution of the content BBB is started. 15 will be notified.

  In addition, the above-mentioned 1 minute before can also be made earlier like 3 minutes ago and 5 minutes ago. In this case, an extra bandwidth is secured, but the number of times that the bandwidth setting is tried can be increased, so that the possibility of failing to secure the bandwidth can be reduced.

  At 10:00, the distribution of the content CCC is completed and the distribution of the content DDD is started. At this time, since the bit rate is reduced from 15 Mbps to 5 Mbps, the bandwidth notification unit 44 sets the bandwidth of 5 Mbps so that the bandwidth of the content CCC is set, for example, at 10:01 after 1 minute. Will be notified.

  It should be noted that the above 1 minute may be further delayed, such as 3 minutes or 5 minutes later. In this case, an extra band is secured, but it can be received without delay until the content being viewed is completely completed.

  Note that, as described above, if the band setting frequently occurs, the processing load on the STB 17 and the PLC master unit 15 increases. Therefore, when switching to the next content, the band notification unit 44, instead of securing the bit rate of the next content, the bit rate of the next content, and the bit rate of one or more content that follows it, Of these, the PLC master unit 15 may be notified so as to secure the maximum one. In this case, since the frequency | count of a band setting can be reduced, the burden of the process in STB17 and the PLC main | base station 15 can be eased.

  For example, in FIG. 11, when viewing the channel CH1, the distribution of the content AAA is completed at 9:00 and the distribution of the content BBB is started, and then the distribution of the content CCC is started. At this time, instead of notifying the content BBB bit rate of 10 Mbps at 8:59 and notifying the content CCC bit rate of 15 Mbps at 9:14, the larger bit rate of the content BBB / CCC bit rate is used. 15 Mbps may be notified at 8:59.

  In this case, during the distribution period of the content BBB, a band of 15 Mbps is secured where originally a band of 10 Mbps may be secured. However, since the distribution period of the content BBB is relatively short at 15 minutes, an extra band is secured. The period is shortened. As described above, the above method is effective when the band change for the content having a short distribution period is omitted. The content BBB, CCC, DDD, EEE distributed in the time zone after 9:00, that is, the time zone from 9:00 to 12:00 (second time zone) is set to the maximum bit rate. You may make it the object to select.

[Embodiment 8]
Next, still another embodiment of the present invention will be described with reference to FIG. The content distribution system 11 of the present embodiment is different from the content distribution system 11 shown in FIGS. 12 to 15 only in the function of the bandwidth notification unit 44, and the other configurations are the same. In addition, the same code | symbol is attached | subjected to the structure and process similar to the structure and process demonstrated in the said embodiment, and the description is abbreviate | omitted.

  In the present embodiment, the bandwidth notification unit 44 determines whether the sufficient bandwidth increases or decreases from the current sufficient bandwidth before reaching the switching time at which the sufficient bandwidth stored in the determined bandwidth storage unit 47 is switched. . When the sufficient bandwidth increases, the bandwidth notification unit 44 notifies the PLC master unit 15 of the increased sufficient bandwidth via the communication unit 33 at a time before a predetermined time before reaching the switching time. As a result, the switching time secures a band necessary for receiving the content of each channel distributed in the period (second time zone) from the switching time to the next switching time. Therefore, it is possible to reliably receive the content whose distribution is started without delay.

  On the other hand, when the sufficient bandwidth decreases, the bandwidth notification unit 44 notifies the PLC master unit 15 of the decreased sufficient bandwidth via the communication unit 33 at a time after a predetermined time before reaching the switching time. . Thereby, after the switching time, the sufficient bandwidth before the decrease is changed to the sufficient bandwidth after the decrease. Therefore, it is possible to reliably receive the content distributed until the switching time without delay until the distribution end time, and it is possible to reliably receive the content distributed after the switching time without delay.

  FIG. 29 is a flowchart showing the flow of processing in the STB 17 of the content distribution system 11 of this embodiment. The process shown in the figure is different from the process shown in FIG. 13 in that steps S220 to 222 are performed instead of step S96, and the other processes are the same.

  In step S220, the bandwidth notification unit 44 determines whether or not the next sufficient bandwidth increases from the current sufficient bandwidth. When the next sufficient bandwidth is increased (YES in step S220), bandwidth notification unit 44 reaches a predetermined time (for example, one minute) before the time for switching to the next sufficient bandwidth (in step S221). YES), the bandwidth notification unit 44 notifies the PLC master unit 15 of the bit rate (required bandwidth) of the next content (step S97).

  On the other hand, when the next sufficient bandwidth is decreasing (NO in step S220), bandwidth notification unit 44 reaches a predetermined time (for example, 1 minute later) after the time of switching to the next sufficient bandwidth (step S222). The bandwidth notification unit 44 notifies the PLC master unit 15 of the bit rate (required bandwidth) of the next content (step S97).

  In the example of FIG. 14, since the bandwidth is sufficiently reduced from 13 Mbps to 9 Mbps at 8:30, the bandwidth notification unit 44 sets the bandwidth of 9 Mbps at 8:31, for example, 1 minute after 8:30. Thus, the PLC master unit 15 is notified.

  Further, since the sufficient bandwidth increases from 9 Mbps to 12 Mbps at 11:00, the bandwidth notification unit 44 sets the PLC so that the bandwidth of 12 Mbps is set at 10:59, for example, 1 minute before 11:00. The master unit 15 is notified.

  By the way, when the user finishes viewing the content, the user continues to view the content distributed on the channel, and when the user is not interested in the content, the user often immediately switches the channel and views another content. For example, it is assumed that the user views the content JJ on the channel CH3 and views the content KKK at 11:00, but is not interested, and therefore switches to the channel CH1 at 11:01 to view the content EEE.

  In this case, in the content distribution system 11 shown in FIG. 28, the bandwidth notification unit 44 notifies the PLC master unit 15 to set the bit rate from 7 Mbps to 11 Mbps at 10:59, and from 11 Mbps at 11:01. The PLC master unit 15 is notified to set the bit rate to 12 Mbps. In other words, the bandwidth change request is requested to the PLC master unit 15 twice during 2 minutes.

  On the other hand, in this embodiment, the bandwidth notification unit 44 only notifies the PLC master unit 15 to set the bit rate from 9 Mbps to 12 Mbps at 10:59, and the bandwidth change request can be made once. That's it.

  As described above, the bandwidth determination unit 42 sets a sufficient bandwidth as the sum of the maximum bit rate and the second bit rate among the bit rates of all contents scheduled to be distributed at a certain time. You may decide. In this case, both the content before switching and the content after switching can be reliably received without delay.

  In the present embodiment, the band notification unit 44 determines whether the sufficient band increases or decreases, but the band determination unit 42 may determine. That is, when the sufficient bandwidth increases, the bandwidth determination unit 42 changes the switching time at which the sufficient bandwidth is switched to a time before the predetermined time, while when the sufficient bandwidth decreases, the switching time changes. May be changed to the time after the predetermined time and stored in the determined band storage unit 47. In this case, the processing of the bandwidth determination unit 42 increases, but the processing of steps S220 to S222 in the bandwidth notification unit 44 becomes unnecessary.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  For example, although the video content has been described in the above embodiment, the present invention can also be applied to other data such as audio content and AV (Audio-Visual) content.

  Finally, each block of the VoD server 12, the PLC master unit 15, and the STB 17, in particular, the control unit 31 may be configured by hardware logic, or may be realized by software using a CPU as follows. .

  That is, the VoD server 12, the PLC master unit 15, and the STB 17 include a CPU that executes instructions of a control program that realizes each function, a ROM (read only memory) that stores the program, a RAM that expands the program, and the program And a storage device (recording medium) such as a memory for storing various data. The object of the present invention is to read the program code (execution format program, intermediate code program, source program) of the control program of the VoD server 12, the PLC master unit 15, and the STB 17, which is software that realizes the functions described above, with a computer. The recording medium recorded as possible is supplied to the VoD server 12, the PLC master unit 15, and the STB 17, and the computer (or CPU or MPU) reads and executes the program code recorded on the recording medium. Achievable.

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  Further, the VoD server 12, the PLC master unit 15, and the STB 17 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Further, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired communication such as IEEE 1394, USB, power line carrier communication, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth, etc. (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  Since the present invention can quickly switch data, it can be applied to a communication device, a communication system, a communication method, a communication program, and a recording medium that transmit and receive data from a server via a network.

Claims (22)

A communication device connected to a network and receiving data from a server via one or more networks including the network,
Necessary band acquisition means for acquiring information on a necessary band, which is a necessary band for transmitting the data, for each of the plurality of data to be received;
Band determining means for determining a sufficient band, which is a sufficient band when transmitting any of the plurality of data to be received, based on information of the required band acquired by the required band acquiring means;
Band setting request means for making a request to the management device that manages the transmission of data in the network so as to set the sufficient band determined by the band determining means ,
The plurality of data to be received is a plurality of data broadcast at the same time and includes at least a plurality of data receivable from the server . A setting means for setting a first time zone including the current time;
2. The communication according to claim 1, wherein the bandwidth determination unit determines the sufficient bandwidth using data that can be received in the first time zone set by the setting unit as data to be received. apparatus. The setting means further sets a second time zone starting from a time after the end of the first time zone,
The bandwidth determination unit adds the data receivable in the second time zone set by the setting unit to the data to be received, and determines the sufficient bandwidth. The communication device described. Further comprising setting means for setting a first time zone including the current time and a second time zone starting from a time after the end of the first time zone,
The band determining means determines the sufficient band as data to be received as data that can be received in the second time zone set by the setting means,
When the sufficient bandwidth is larger than the bandwidth reserved in the first time zone, the bandwidth setting requesting unit sets the sufficient bandwidth before the start of the second time zone. The communication apparatus according to claim 1, wherein a request is made to the management apparatus. Further comprising setting means for setting a first time zone including the current time and a second time zone starting from a time after the end of the first time zone,
The band determining means determines the sufficient band as data to be received as data that can be received in the second time zone set by the setting means,
When the sufficient bandwidth is smaller than the bandwidth reserved in the first time zone, the bandwidth setting requesting unit performs the management so as to set the sufficient bandwidth after the end of the first time zone. The communication apparatus according to claim 1, wherein a request is made to the apparatus.   The said setting means sets the earliest time among the time when the reception of the data which can be received at the beginning is scheduled to end for each of the first and second time zones as the end. The communication device according to any one of 5 to 5.   The said setting means sets the start and end of a 1st time slot | zone, and the start and end of a 2nd time slot | zone based on a predetermined rule, The any one of Claim 3-6 characterized by the above-mentioned. The communication apparatus as described in.   The communication device according to any one of claims 3 to 7, wherein the setting means sets the end of the first time zone as the start of the second time zone. The band determination unit is configured to receive first data, which is currently received data, and second data, which are a plurality of data scheduled to be received after the reception of the first data, as data to be received. The communication apparatus according to claim 1, wherein the sufficient bandwidth is determined. The band determining means determines the sufficient band as the data to be received by using the second data, which is a plurality of data scheduled to be received after the end of receiving the first data, which is currently being received. And
When the sufficient bandwidth is larger than the bandwidth secured during reception of the first data, the bandwidth setting requesting unit sets the sufficient bandwidth before the scheduled reception start time of the second data. The communication apparatus according to claim 1, wherein the communication apparatus makes a request to the management apparatus. The band determining means determines the sufficient band as the data to be received by using the second data, which is a plurality of data scheduled to be received after the end of receiving the first data, which is currently being received. And
If the sufficient bandwidth is smaller than the bandwidth reserved during reception of the first data, the bandwidth setting requesting unit sets the sufficient bandwidth after the scheduled reception end time of the first data. The communication apparatus according to claim 1, wherein a request is made to the management apparatus as described above.   The communication apparatus according to any one of claims 9 to 11, wherein the second data is data scheduled to be received immediately after the reception of the first data.   2. The communication according to claim 1, wherein the bandwidth determination unit determines the sufficient bandwidth as data to be received as data corresponding to the information on the required bandwidth acquired by the required bandwidth acquisition unit. apparatus.   The bandwidth determining means determines the sufficient bandwidth as data to be received from data that can be received from the server among the data corresponding to the required bandwidth information acquired by the required bandwidth acquisition means. The communication device according to claim 13, characterized in that:   The communication apparatus according to any one of claims 1 to 14, wherein the band determination unit sets the maximum band among the necessary bands of the data to be received as the sufficient band.   16. The bandwidth determination unit according to claim 1, wherein the bandwidth determination means sets the sum of the maximum bandwidth and the second largest bandwidth among the necessary bandwidths of the data to be received as the sufficient bandwidth. The communication apparatus according to claim 1. Network,
A management device connected to the network and managing transmission of data in the network;
A communication system comprising: the communication device according to claim 1 connected to the network.   18. The communication system according to claim 17, wherein the network is a power line carrier communication network. A communication system according to claim 17 or 18,
A data transmission system comprising a server connected to the communication system via a network of the communication system or a network different from the network and transmitting data to the communication device. A method for controlling a communication device connected to a network and receiving data from a server via one or more networks including the network,
A necessary bandwidth acquisition step of acquiring information on a necessary bandwidth, which is a bandwidth necessary for transmitting the data, for each of the plurality of data to be received;
Based on the necessary bandwidth information acquired in the necessary bandwidth acquisition step, a bandwidth determination step for determining a sufficient bandwidth, which is a sufficient bandwidth when transmitting any of the plurality of data to be received,
To set a sufficient band determined by said individual band determination step, and Nde including a bandwidth setting request step of requesting to the management device for managing transmission of data in said network,
The method of controlling a communication device, wherein the plurality of data to be received includes a plurality of data broadcast at the same time and includes at least a plurality of data receivable from the server .   A communication device control program for operating the communication device according to any one of claims 1 to 16, wherein the communication device control program causes a computer to function as each of the means.   A computer-readable recording medium on which the communication device control program according to claim 21 is recorded.

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