JP7428009B2 - Broadcast retransmission system, station side equipment, home side equipment, and broadcast retransmission method - Google Patents

Description

The present disclosure relates to a broadcast retransmission system, a station-side device, a home-side device, and a broadcast retransmission method.

Conventionally, technology has been developed to transmit content using MMTP (MPEG Media Transport Protocol) packets.

For example, the Radio Industry Association, “Media Transport Method Using MMT in Digital Broadcasting ARIB STD-B60 Version 1.9”, March 24, 2017 (Non-Patent Document 1), states that broadcasting using the MMT method system is disclosed.

In this broadcasting system, MMT packets containing program information such as audio information and video information are stored in the payload of an IP packet. The IP packet is stored in the payload of a TLV (Type Length Value) packet.

Radio Industries Association, “Media transport method using MMT in digital broadcasting ARIB STD-B60 1.9 edition”, March 24, 2017

For example, when performing an IP retransmission service that transmits received broadcast waves to homes via an IP (Internet Protocol) network, the packets included in the broadcast waves are stored in IP packets and retransmitted to each home. There are several possible configurations. A better technique for performing such retransmissions is desired.

The present disclosure has been made in order to solve the above-mentioned problems, and the purpose is to provide a broadcast retransmission system that can build an excellent system for retransmitting broadcast waves to the home side via a network, An object of the present invention is to provide a device, a home device, and a broadcast retransmission method.

(1) The broadcast retransmission system of the present disclosure includes a station-side device that receives a broadcast wave containing program information, generates and transmits an IP packet that stores the program information and is synchronized with a reference clock; The device receives the IP packets transmitted from the station-side device, measures the reception rate of the IP packets, adjusts its own clock based on the measured reception rate, thereby regenerating the reference clock, and regenerating the reference clock. and a home-side device that outputs broadcast waves containing information about the program using a reproduced clock that is a reference clock.

(7) The station-side device of the present disclosure includes a receiving unit that receives broadcast waves including program information, and a reference clock that is synchronized with a reference clock that stores the program information included in the broadcast waves received by the receiving unit. a transmitting unit that performs a transmission process of generating and transmitting an IP packet, and the transmitting unit is configured to transmit the IP packet so that the reference clock can be recognized by a residential device to which the IP packet is transmitted, in the transmission process. generate.

(8) The home-side device of the present disclosure includes a receiving unit that receives an IP packet synchronized with a reference clock and storing information about a program included in a broadcast wave from the station-side device; a reproduction unit that reproduces the reference clock using information given in the transmission process of the IP packet in the station-side device; and a reproduction unit that reproduces information about the program using the reproduced clock that is the reference clock reproduced by the reproduction unit. and a transmitter that outputs a broadcast wave including.

(9) The broadcast retransmission method of the present disclosure is a broadcast retransmission method in a broadcast retransmission system, in which the station-side device uses an IP synchronized with a reference clock that stores program information included in received broadcast waves. generating and transmitting a packet, and the home-side device measuring the reception rate of the IP packets transmitted from the station-side device and adjusting its own clock based on the measured reception rate. The method includes a step of reproducing a reference clock, and a step of the home-side device outputting a broadcast wave containing information about the program using the regenerated clock that is the regenerated reference clock.

One aspect of the present disclosure can be realized not only as a broadcast retransmission system including such a characteristic processing unit, but also as a program for causing a computer to execute the steps of such characteristic processing. Further, one aspect of the present disclosure can be realized as a semiconductor integrated circuit that realizes part or all of a broadcast retransmission system.

One aspect of the present disclosure can be realized not only as a station-side device including such a characteristic processing unit, but also as a method in which such characteristic processing is performed as steps, or as a method in which such steps are executed by a computer. It can be realized as a program to do this. Further, one embodiment of the present disclosure can be realized as a semiconductor integrated circuit that realizes part or all of the station-side device.

One aspect of the present disclosure can be realized not only as a home-side device including such a characteristic processing unit, but also as a method in which such characteristic processing is performed as steps, or in which such steps are executed by a computer. It can be realized as a program to do this. Further, one embodiment of the present disclosure can be realized as a semiconductor integrated circuit that implements part or all of a home-side device.

According to the present disclosure, it is possible to construct an excellent system that retransmits broadcast waves to the home side via a network.

FIG. 1 is a diagram showing the configuration of a broadcast retransmission system according to a first embodiment of the present disclosure. FIG. 2 is a diagram showing the configuration of a station-side device in the broadcast retransmission system according to the first embodiment of the present disclosure. FIG. 3 is a diagram showing the configuration of a home device in the broadcast retransmission system according to the first embodiment of the present disclosure. FIG. 4 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the station-side device according to the first embodiment of the present disclosure. FIG. 5 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the home device according to the first embodiment of the present disclosure. FIG. 6 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the station-side device according to the first embodiment of the present disclosure. FIG. 7 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the home device according to the first embodiment of the present disclosure. FIG. 8 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the home device according to the first embodiment of the present disclosure. FIG. 9 is a diagram showing the configuration of a broadcast retransmission system according to the second embodiment of the present disclosure. FIG. 10 is a diagram showing the configuration of a station-side device in a broadcast retransmission system according to a second embodiment of the present disclosure. FIG. 11 is a diagram showing the configuration of a home device in a broadcast retransmission system according to a second embodiment of the present disclosure.

First, the contents of the embodiments of the present disclosure will be listed and explained.

(1) A broadcast retransmission system according to an embodiment of the present disclosure is a station that receives broadcast waves containing program information, generates and transmits IP packets that store the program information and are synchronized with a reference clock. A side device receives the IP packets transmitted from the station side device, measures the reception rate of the IP packets, and reproduces the reference clock by adjusting its own clock based on the measured reception rate. and a home-side device that outputs a broadcast wave containing information about the program using the reproduced clock that is the reproduced reference clock.

With such a configuration, for example, broadcast waves can be transmitted to the home side via the same transmission path as IP packets related to services other than broadcasting, so the network configuration between the station side and the home side can be simplified. can. For example, when connecting the central office side and the residential side using optical fiber, it is possible to suppress the increase in equipment for amplifying optical signals, etc., and to ensure transmission quality compared to a configuration that uses wavelength multiplexing. The transmission distance can be extended at the same time. Therefore, it is possible to construct an excellent system for retransmitting broadcast waves to the home side via a network.

(2) Preferably, the station-side device generates the IP packet for each channel of digital terrestrial broadcasting, multiplexes and transmits the generated IP packets of the plurality of channels,
The home device selects any one of the plurality of channels and measures the reception rate of the selected channel.

With such a configuration, it is possible to simplify the network configuration between the station side and the home side for distributing terrestrial digital broadcasting programs, and to perform clock regeneration with simple processing in the home side device.

(3) More preferably, the station-side device generates a program packet that is a plurality of TS packets in which information about the program is divided and stored, and inserts a null packet between the program packets to increase the transmission rate. and stores the adjusted program packet and the null packet in the IP packet and transmits the same, and the home-side device stores the program packet and the null packet stored in the received IP packet in a buffer. and monitors the amount of storage in the buffer, and adjusts the frequency of its own clock based on the amount of storage.

This configuration simplifies the processing in the station equipment for providing the information used when reproducing the reference clock to the home equipment, and also simplifies the processing in the home equipment for transmitting broadcasting methods that include programs on multiple channels. Clock recovery can be performed by simple processing without using, for example, an expensive oscillator in the side device.

(4) More preferably, the station-side device generates a plurality of TTS packets in which information about the program is divided and stored, stores the generated TTS packets in the IP packet and transmits the same, and transmits the generated TTS packets to the IP packet. The side device adjusts the frequency of its own clock based on the time stamp in the TTS packet stored in the received IP packet.

With such a configuration, the amount of transmission in the network between the office side and the home side can be suppressed, compared to a configuration using null packets, while providing the home side device with information used when regenerating the reference clock. Furthermore, in a system that transmits a broadcast system that includes programs on a plurality of channels, clock regeneration can be performed by simple processing without using, for example, an expensive oscillator in the home device.

(5) Preferably, the home-side device adjusts its own clock so that the accuracy of the reproduced clock based on the reference clock approaches ±0.3 ppm.

With this configuration, for example, in a system in which a home device modulates a frame containing program information contained in an IP packet and outputs it as a broadcast wave, the home device can perform modulation without using an expensive oscillator. The required clock accuracy can be obtained.

(6) Preferably, the broadcast retransmission system further includes a multiplexer that multiplexes and transmits the broadcast IP packet, which is the IP packet transmitted from the station-side device, and other IP packets received from the network. and a demultiplexer that receives the IP packet transmitted from the multiplexer and outputs the broadcast IP packet and the other IP packets separately.

With this configuration, it is possible to realize a system that simplifies the network configuration between the station side and the home side and transmits broadcast waves to the home side via the same transmission path as IP packets related to services other than broadcasting. .

(7) The station-side device according to the embodiment of the present disclosure includes a receiving unit that receives broadcast waves including program information, and a station-side device that includes information included in the broadcast waves received by the receiving unit. a transmission unit that performs a transmission process of generating and transmitting an IP packet synchronized with a reference clock and storing information of the program to be transmitted, the transmission unit being configured to The IP packet is generated so that the reference clock can be recognized in the side device.

With such a configuration, for example, broadcast waves can be transmitted to the home side via the same transmission path as IP packets related to services other than broadcasting, so the network configuration between the station side and the home side can be simplified. can. For example, when connecting the central office side and the residential side using optical fiber, it is possible to suppress the increase in equipment for amplifying optical signals, etc., and to ensure transmission quality compared to a configuration that uses wavelength multiplexing. The transmission distance can be extended at the same time. Therefore, it is possible to construct an excellent system for retransmitting broadcast waves to the home side via a network.

(8) The home device according to the embodiment of the present disclosure receives from the station device an IP packet synchronized with a reference clock that stores information about a program included in a broadcast wave. a receiving section; a reproducing section that regenerates the reference clock using information received by the receiving section and given in the transmission processing of the IP packet in the station-side device; and a transmitter that outputs broadcast waves containing information about the program using a reproduced clock that is a reference clock.

With such a configuration, for example, broadcast waves can be transmitted to the home side via the same transmission path as IP packets related to services other than broadcasting, so the network configuration between the station side and the home side can be simplified. can. For example, when connecting the central office side and the residential side using optical fiber, it is possible to suppress the increase in equipment for amplifying optical signals, etc., and to ensure transmission quality compared to a configuration that uses wavelength multiplexing. The transmission distance can be extended at the same time. Therefore, it is possible to construct an excellent system for retransmitting broadcast waves to the home side via a network.

(9) The broadcast retransmission method according to the embodiment of the present disclosure is a broadcast retransmission method in a broadcast retransmission system, in which the station-side device uses a standard in which information about a program included in received broadcast waves is stored. generating and transmitting an IP packet synchronized with a clock, and the home device measuring the reception rate of the IP packets transmitted from the station device, and adjusting its own clock based on the measured reception rate. The method includes the step of reproducing the reference clock by adjusting the reference clock, and the step of the home-side device outputting a broadcast wave including information on the program using the reproduced clock that is the regenerated reference clock.

With such a configuration, for example, broadcast waves can be transmitted to the home side via the same transmission path as IP packets related to services other than broadcasting, so the network configuration between the station side and the home side can be simplified. can. For example, when connecting the central office side and the residential side using optical fiber, it is possible to suppress the increase in equipment for amplifying optical signals, etc., and to ensure transmission quality compared to a configuration that uses wavelength multiplexing. The transmission distance can be extended at the same time. Therefore, it is possible to construct an excellent system for retransmitting broadcast waves to the home side via a network.

Embodiments of the present disclosure will be described below with reference to the drawings. In addition, the same reference numerals are attached to the same or corresponding parts in the drawings, and the description thereof will not be repeated. Furthermore, at least some of the embodiments described below may be combined arbitrarily.

<First embodiment>
FIG. 1 is a diagram showing the configuration of a broadcast retransmission system according to a first embodiment of the present disclosure.

Referring to FIG. 1, a broadcast retransmission system 301 includes a station side device 101, an OLT (Optical Line Terminal) 151, a D-ONU (Data-Optical Network Unit) 152, and a VDSL (Very high bit rate Digital S). ubscriber Line) device 153 and a home device 202.

The station-side device 101 and the OLT 151 are installed, for example, in a station building of an operator that provides cable television broadcasting. The D-ONU 152, the VDSL device 153, and the home device 202 are provided in, for example, an apartment complex.

For example, an external antenna 95 is connected to the station-side device 101. The station-side device 101 receives, for example, a broadcast wave including a stream. The broadcast wave is, for example, a broadcast wave of digital terrestrial broadcasting.

The stream includes program information and the like. The program information includes, for example, audio information, video information, EPG (Electronic Program Guide) information, SI information (Service Information), subtitle information, and the like.

The audio information and video information are compressed and encrypted according to a predetermined method, for example.

The station-side device 101 generates IP packets for each channel of digital terrestrial broadcasting, multiplexes the generated IP packets for a plurality of channels, and transmits the multiplexed IP packets.

More specifically, the station-side device 101 includes four broadcast wave IP transmission devices 161. The broadcast wave IP transmission device 161 acquires program information from the broadcast wave, generates an IP packet (hereinafter also referred to as a broadcast IP packet) including the acquired program information, and transmits it to the OLT 151. Note that the station-side device 101 may be configured to include one, two, three, or five or more broadcast wave IP transmission devices 161.

The OLT 151 is an example of a multiplexing device, and receives broadcast IP packets received from the station-side device 101 and other IP packets received from an upper network such as the Internet, and processes the received broadcast IP packets and other IP packets. Multiplex and transmit. More specifically, OLT 151 generates an optical signal containing each IP packet and transmits it to one or more D-ONUs 152 via an optical network including optical fiber 251.

The D-ONU 152 is an example of a demultiplexing device, and acquires IP packets included in the optical signal received from the OLT 151, and divides each acquired IP packet based on the destination IP address or port number of the acquired IP packet. is divided into broadcast IP packets and other IP packets and output. The D-ONU 152 transmits broadcast IP packets to the home device 202 and other IP packets to the VDSL device 153.

The home device 202 acquires program information from the broadcast IP packet received from the D-ONU 152, generates a broadcast wave containing the acquired program information, and transmits the broadcast wave to each TV monitor 91 in an apartment complex via an antenna line. Output. This makes it possible to provide broadcast programs to homes where optical fiber is not installed. Furthermore, broadcast programs can be provided via existing antenna lines without providing an STB (Set Top Box) or the like capable of processing IP packets in each home.

The TV monitor 91 reproduces programs based on the audio information and video information included in the broadcast waves received from the home device 202.

The VDSL device 153 generates a communication signal containing other IP packets received from the D-ONU 152, and transmits it to the home device 92, such as a personal computer, via a telephone line.

Note that the broadcast retransmission system 301 is not limited to an apartment complex, and may be configured to transmit broadcast waves to a plurality of single-family houses and transmit other IP packets, for example, as a countermeasure against difficult viewing.

FIG. 2 is a diagram showing the configuration of a station-side device in the broadcast retransmission system according to the first embodiment of the present disclosure.

Referring to FIG. 2, the broadcast wave IP transmission device 161 in the station side device 101 acquires program information for a plurality of channels, for example, four channels, from the broadcast wave, and transmits broadcast IP packets storing the acquired program information. Each is generated and sent to the OLT 151.

A common station-side clock is supplied to each broadcast wave IP transmission device 161. Note that any one of the broadcast wave IP transmission devices 161 may generate a station-side clock and supply it to each of the other broadcast wave IP transmission devices 161. The frequency of the station-side clock is, for example, 10 MHz.

The broadcast wave IP transmission device 161 includes a tuner 1, which is an example of a receiving section, and a transmitting section 12. The transmitter 12 includes a PID (Packet Identifier) filter 2, a multiplexer 3, and an IP transmitter 4. Broadcast wave IP transmission device 161 includes four sets of tuner 1, PID filter 2, and multiplexer 3 for four channels. Note that the broadcast wave IP transmission device 161 may be configured to include one such set for one channel.

The tuner 1 receives and demodulates a broadcast wave, and outputs part or all of the broadcast TS frame of its own channel included in the broadcast wave.

For example, the tuner 1 receives a broadcast wave including program information etc. via the external antenna 95, and obtains a stream included in the received broadcast wave.

More specifically, the tuner 1 demodulates the received broadcast wave and converts it into a digital signal. Based on the digital signal, the tuner 1 generates a plurality of TS packets (hereinafter also referred to as program packets) in which program information is divided and stored, and a TS packet in which null data is stored (hereinafter referred to as a null packet). ) etc. are output to the PID filter 2. A stream is composed of program packets and null packets.

The PID filter 2 refers to the PID of each TS packet received from the tuner 1, deletes null packets, and outputs the program packet to the multiplexer 3.

The multiplexer 3 operates according to the timing of the reference clock received from the clock generator 5, and performs processing to adjust the transmission rate of the stream in its own channel.

The clock generator 5 generates a reference clock by frequency-dividing or multiplying the received station-side clock, and outputs it to each circuit such as the multiplexer 3 .

The station-side device 101 generates and transmits a broadcast IP packet that stores program information and is synchronized with a reference clock.

More specifically, the transmitting unit 12 performs a transmission process of generating and transmitting a broadcast IP packet synchronized with a reference clock, which stores information about a program included in the broadcast wave received by the tuner 1. In the transmission process, the transmitter 12 generates a broadcast IP packet whose reference clock can be recognized by the home device 202 to which the broadcast IP packet is transmitted. That is, in the transmission process, the transmitter 12 performs a process of providing the home device 202 with information used when reproducing the reference clock in the home device 202 to which the broadcast IP packet is transmitted. In other words, the transmitter 12 transmits the broadcast IP packet in a form that can represent the reference clock, that is, in a reproducible manner.

The IP transmitter 4 generates a broadcast IP packet for each channel in which a plurality of TS packets received from each multiplexer 3 are stored in the payload, and transmits it to the OLT 151 . For example, seven TS packets are stored in the broadcast IP packet.

The OLT 151 multiplexes the stream of each channel, that is, each broadcast IP packet, received from each broadcast wave IP transmission device 161, and converts each multiplexed broadcast IP packet and other IP packets received from the upper network into optical signals. and send.

FIG. 3 is a diagram showing the configuration of a home device in the broadcast retransmission system according to the first embodiment of the present disclosure.

Referring to FIG. 3, home device 202 includes an IP receiving section 31, a transmitting section 32, and a reproducing section 33. The transmitting section 32 includes a mixing circuit 25, and also includes 13 sets of a packet filter 21, a buffer 22, a broadcast TS multiplexing section 23, and an OFDM modulating section 24 for a plurality of channels, for example, 13 channels. Note that the transmitter 32 may be configured to include one such set for one channel. The reproduction unit 33 includes a selection unit 41, a buffer amount monitoring unit 42, a buffer amount increase/decrease time measurement unit 43, a local clock deviation amount calculation unit 44, a local clock control unit 45, and a local clock generation unit 46. .

The home device 202 receives broadcast IP packets transmitted from the station device 101, measures the reception rate of the broadcast IP packets, and reproduces the reference clock by adjusting its own clock based on the measured reception rate. do. Then, the home device 202 outputs a broadcast wave containing information about the program using the reproduced clock that is the reproduced reference clock.

More specifically, the home device 202 uses a reproduced clock to generate a broadcast TS frame storing program information included in a broadcast IP packet for each channel, and then generates a broadcast TS frame for the plurality of channels. The multiplexed and modulated signals are output as broadcast waves.

In the home device 202, the IP receiving unit 31 receives from the station device 101 a broadcast IP packet that is synchronized with a reference clock and stores information about a program included in the broadcast wave.

The transmitting unit 32 outputs a broadcast wave containing information on the program using a reproduced clock that is a reference clock reproduced by the reproducing unit 33.

More specifically, the IP receiving unit 31 outputs the broadcast IP packets received from the D-ONU 152 to each packet filter 21.

The packet filter 21 selects the broadcast IP packet corresponding to its own channel from among the broadcast IP packets received from the IP receiver 31 by referring to the destination IP address or port number of the broadcast IP packet, and selects the broadcast IP packet corresponding to its own channel. Each TS packet stored in the broadcast IP packet is stored in the buffer 22.

Note that the packet filter 21 may be configured to accumulate selected broadcast IP packets in the buffer 22.

The broadcast TS multiplexing unit 23 extracts the TS packets from the buffer 22 according to the timing of the reproduction clock received from the reproduction unit 33, deletes null packets from each extracted TS packet in Examples 1 and 2 described later, and deletes null packets from each extracted TS packet. In example 3, the time stamp is deleted and the program packet is re-multiplexed into the broadcast TS frame. The broadcast TS multiplexing unit 23 inserts null packets between program packets in the broadcast TS frame so that the transmission rate of the stream becomes a predetermined set bit rate. Broadcast TS multiplexing section 23 outputs the generated broadcast TS frame to OFDM modulation section 24 .

The OFDM modulation unit 24 generates a modulated signal obtained by performing OFDM modulation on the broadcast TS frame received from the broadcast TS multiplexing unit 23 and has a frequency corresponding to its own channel according to the timing of the reproduction clock received from the reproduction unit 33. It generates a modulated signal and outputs the generated modulated signal to the mixing circuit 25.

The mixing circuit 25 mixes the modulated signals received from the OFDM modulating section 24 of each channel and outputs the mixed signal as a broadcast wave to the antenna line. As a result, the streams of each channel are multiplexed and output.

For example, the home device 202 selects one of the plurality of channels and measures the reception rate of the selected channel.

More specifically, the reproduction unit 33 in the home device 202 reproduces the reference clock using information given in the broadcast IP packet transmission process in the station device 101.

Specifically, the selection unit 41 selects any one of the buffers 22 of each channel, and connects the selected buffer 22 and the buffer amount monitoring unit 42. For example, the selection unit 41 selects the buffer 22 of a specific preset channel.

Alternatively, the selection unit 41 detects channels in use and measures the reception rate on any one of the detected channels. That is, the selection unit 41 selects the buffer 22 according to the detection result of the used channel.

The buffer amount monitoring section 42 monitors the buffer amount, that is, the amount of data accumulated in the connected buffer 22, and outputs the monitoring result to the buffer amount increase/decrease time measuring section 43.

The buffer amount increase/decrease time measuring unit 43 measures the increase/decrease time of the storage amount in the buffer 22 based on the monitoring result of the buffer amount monitoring unit 42 . For example, the buffer amount increase/decrease time measuring unit 43 holds a first threshold value that is larger than the reference value of the buffer amount and a second threshold value that is smaller than the reference value of the buffer amount. The time until it becomes less than the threshold is measured, and the measurement result is output to the local clock deviation amount calculation unit 44.

The local clock deviation amount calculation unit 44 calculates the deviation amount of the local clock based on the measurement result received from the buffer amount increase/decrease time measurement unit 43 and outputs the calculation result to the local clock control unit 45.

The local clock control unit 45 outputs a control signal to the local clock generation unit 46 according to the calculation result received from the local clock deviation amount calculation unit 44, thereby adjusting the frequency of the local clock output from the local clock generation unit 46. adjust. As a result, the speed at which the broadcast TS multiplexing unit 23 extracts TS packets from the buffer 22 is changed.

For example, the local clock control unit 45 changes the frequency of the local clock at a predetermined resolution so that the buffer amount of the buffer 22 converges to the reference value. For example, the local clock control unit 45 repeats the operation of changing the frequency of the local clock by the adjustment amount closest to the deviation amount indicated by the above calculation result.

The local clock generation section 46 outputs the local clock whose frequency is set according to the control signal received from the local clock control section 45 as a reproduced clock to the broadcast TS multiplexing section 23, OFDM modulation section 24, etc. of each channel. As a result, it is possible to generate a reproduced clock that follows the reference clock in the station-side device 101, and there is no need to provide a large number of oscillators for each channel.

As described above, the broadcast retransmission system 301 has a configuration in which frames of multiple channels are multiplexed, modulated, and output as broadcast waves, so that in an environment where there are multiple distribution destinations of programs from the home-side device 202, the broadcast retransmission system 301 can be used for distribution. A program can be viewed using a normal broadcast wave receiving device without providing a receiving device such as an STB that supports IP packets for each destination, and the cost of broadcast receiving equipment can be reduced.

Furthermore, in the broadcast retransmission system 301, the station device 101 uses a reference clock to synchronize and transmit streams of each channel, and the home device 202 monitors any one of the channels. In addition, with a simple configuration, streams of each channel can be multiplexed and output in synchronization with each other in the home device 202.

In addition, the broadcast retransmission system 301 has a configuration that performs clock recovery with a predetermined resolution based on the bit rate of the transmitting side. .3 ppm (parts per million) can be achieved. This eliminates the need for an expensive high-precision oscillator in the home device 202.

That is, the home device 202 adjusts its own clock so that the accuracy of the reproduced clock based on the reference clock asymptotically approaches, or approaches, ±0.3 ppm.

[Flow of operation]
Each device in the broadcast retransmission system 301 is equipped with a computer including a memory, and an arithmetic processing unit such as a CPU in the computer reads a program including some or all of the steps shown in the following diagram from the memory and executes the program. do. The programs for these multiple devices can be installed from outside. The programs of these plurality of devices are stored in respective recording media and distributed.

The transmitting unit 12 in the station-side device 101 provides the home-side device 202 with information used when reproducing the reference clock, that is, the transmission rate of the stream becomes the same set bit rate in the station-side device 101 and the home-side device 202. Broadcast IP packets are generated using null packets or timestamps. Further, the transmitter 12 adjusts the bit rate of each channel using a null packet or adds a time stamp to the TS packet according to the timing of the reference clock.

[Example 1]
FIG. 4 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the station-side device according to the first embodiment of the present disclosure. FIG. 5 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the home device according to the first embodiment of the present disclosure. 4 and 5 show an example in which a null packet is transmitted between the station-side device 101 and the home-side device 202.

Each multiplexer 3 in the transmitter 12 of the station-side device 101 adjusts the transmission rate of the stream to be output to the IP transmitter 4 so as to equalize the transmission rate in each channel, and outputs the stream to the IP transmitter 4.

More specifically, the multiplexer 3 operates according to the timing of the reference clock received from the clock generator 5, and performs processing to adjust the transmission rate of the stream in its own channel to a predetermined set bit rate.

Specifically, referring to FIG. 4, the station-side device 101 generates program packets, which are multiple TS packets in which program information is divided and stored, and inserts a null packet between the program packets. The transmission rate is adjusted, and the adjusted program packet and null packet are stored in an IP packet and transmitted.

In the station-side device 101, the tuner 1 first receives a broadcast wave including a broadcast TS frame. The broadcast TS frame includes TS packets and null packets in the A layer for One Seg, TS packets and null packets in the B layer for high-definition video, and TS packets and null packets in the invalid layer.

The transmission rate of a stream in a broadcast TS frame is, for example, 29.96 Mbps for a 188-byte TS packet.

In this case, the parameters of the broadcast TS frame are that the ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) mode is mode 3, the guard interval is 1/8, the number of segments in the A layer, the modulation method, and the convolutional coding. The rate and time interleaving are 1, QPSK (Quadrature Phase Shift Keying), 2/3 and 4, respectively, and the number of B layer segments, modulation method, convolutional coding rate and time interleaving are 12 and 64QAM (Quadrature Amplitude Modulation), respectively. ), 3/4 and 2.

Also, the rate of TS packets and null packets in the A layer is 0.42 Mbps, the rate of TS packets and null packets in the B layer is 16.85 Mbps, and the rate of TS packets and null packets in the invalid layer is 12.69 Mbps. (Step S1).

Next, the PID filter 2 deletes the null packet and also deletes each TS packet in the A layer. As a result, program packets of the B layer are selectively output to the multiplexer 3, and the stream transmission rate becomes, for example, less than 16.85 Mbps for a 188-byte TS packet (step S2).

Next, the multiplexing unit 3 selects whether or not to insert a null packet between program packets so that the transmission rate of the stream becomes the set bit rate, for example, 17.00 Mbps (step S3).

Next, the IP transmitter 4 generates a broadcast IP packet in which the plurality of TS packets received from the multiplexer 3 are stored in the payload, and transmits it to the home device 202 via the OLT 151 or the like.

Referring to FIG. 5, the home device 202 stores the program packet and null packet stored in the received broadcast IP packet in the buffer 22, monitors the amount of storage in the buffer 22, and uses the storage amount based on the amount of storage. Adjust the frequency of the clock.

In the home device 202, first, the IP receiving unit 31 receives a broadcast IP packet from the station device 101 (step S5).

Next, the packet filter 21 extracts the broadcast IP packet of its own channel, that is, the target channel, from the stream in which the broadcast IP packets of each channel are multiplexed. The transmission rate of a stream based on each extracted broadcast IP packet is, for example, 17.00 Mbps for a 188-byte TS packet.

More specifically, the packet filter 21 selects the broadcast IP packet corresponding to its own channel from among the broadcast IP packets received from the IP receiver 31 by referring to the destination IP address or port number of the broadcast IP packet. Each TS packet stored in the selected broadcast IP packet is stored in the buffer 22.

That is, in addition to program packets, the packet filter 21 also accumulates, in the buffer 22, null packets inserted by the multiplexer 3 in the station-side device 101. This makes it possible to adjust the frequency of the local clock as described above, and even if the frequency adjustment is performed on any of the channels, the effect of frequency adjustment can be obtained in common for each channel ( Step S6).

Next, TS packets are taken out from the buffer 22 at a set bit rate according to the timing of the reproduced clock, thereby changing the buffer amount. As described above, the reproducing unit 33 monitors the buffer amount of the buffer 22, adjusts the frequency of the local clock, and reproduces the reference clock. The transmission rate of the stream based on TS packets taken out from the buffer 22 is, for example, 17.00 Mbps for TS packets of 188 bytes (step S7).

Next, the broadcast TS multiplexing unit 23 deletes null packets from among the retrieved TS packets and remultiplexes the program packets into the broadcast TS frame according to the timing of the reproduction clock.

In the broadcast TS frame, the A layer is for high-definition video. The transmission rate of a stream in a broadcast TS frame is, for example, 29.96 Mbps for a 188-byte TS packet.

In this case, the parameters of the broadcast TS frame are that the ISDB-T mode is mode 3, the guard interval is 1/16, and the number of segments in the A layer, modulation method, convolutional coding rate, and time interleaving are each 13. , 64QAM, 7/8 and 2. The rate of TS packets and null packets in the A layer is 22.55 Mbps, and the rate of TS packets and null packets in the invalid layer is 7.41 Mbps (step S8).

Next, the OFDM modulator 24 generates a modulated signal by performing OFDM modulation on the broadcast TS frame re-multiplexed by the broadcast TS multiplexer 23 according to the timing of the reproduced clock, and broadcasts the modulated signal via the mixing circuit 25. It is output as a wave (step S9).

[Example 2]
FIG. 6 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the station-side device according to the first embodiment of the present disclosure. FIG. 7 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the home device according to the first embodiment of the present disclosure. 6 and 7 show an example in which a null packet is not transmitted between the station-side device 101 and the home-side device 202, but a time stamp is transmitted.

The station-side device 101 generates a plurality of TTS (Timestamped Transport Stream) packets in which program information is divided and stored, and stores the generated TTS packets in IP packets and transmits them.

Specifically, referring to FIG. 6, steps S11 to S13 are the same as steps S1 to S3 shown in FIG. 4, respectively.

Next, the multiplexer 3 adds a timestamp to the program packet in the stream into which the null packet has been inserted. The timestamp has a value including the inserted null packet (step S14).

Next, the multiplexing unit 3 deletes null packets from the stream to which the timestamp has been added (step S15).

Next, the IP transmitter 4 generates a broadcast IP packet in which a plurality of program packets to which time stamps have been added by the multiplexer 3 are stored in the payload, and transmits it to the home device 202 via the OLT 151 or the like.

Referring to FIG. 7, home device 202 adjusts the frequency of its own clock based on the time stamp in the TTS packet stored in the received broadcast IP packet.

Steps S17 and S18 are similar to steps S5 and S6 shown in FIG. 5, respectively.

Next, the packet filter 21 inserts a null packet based on the timestamp and deletes the timestamp in the stream of each extracted broadcast IP packet.

More specifically, the packet filter 21 determines whether a null packet has been inserted in the multiplexing unit 3 of the broadcast wave IP transmission device 161 based on the time stamp difference between temporally consecutive program packets, A null packet is inserted between the program packets determined to have been inserted. The transmission rate of the stream after the null packet is inserted is, for example, 17.00 Mbps for a 188-byte TS packet (step S19).

Steps S20 to S22 are similar to steps S7 to S9 shown in FIG. 5, respectively.

In Example 2 as well, the configuration using time stamps makes it possible to adjust the frequency of the local clock as in Example 1, and even if the frequency adjustment is performed for which channel among the channels, the frequency adjustment is common to each channel. The effect of frequency adjustment can be obtained.

[Example 3]
FIG. 8 is a diagram illustrating an example of the flow of processing including transmission rate adjustment in the home device according to the first embodiment of the present disclosure. FIG. 8 shows an example in which a null packet is not transmitted between the station-side device 101 and the home-side device 202, but a time stamp is transmitted. In Example 3, the flow of processing including adjustment of the transmission rate in the station-side device 101 is the same as that in FIG. 6 .

In Example 3, the reproduction unit 33 includes a timestamp counter that operates according to the timing of the reproduction clock instead of the buffer amount monitoring unit 42 and the buffer amount increase/decrease time measuring unit 43 shown in FIG.

Referring to FIG. 8, home device 202 adjusts the frequency of its own clock based on the time stamp in the TTS packet stored in the received broadcast IP packet.

Steps S37 and S38 are similar to steps S5 and S6 shown in FIG. 5, respectively.

Next, the time-stamped program packets are retrieved from the buffer 22 at a set bit rate according to the timing of the reproduction clock. The local clock shift amount calculation section 44 in the playback section 33 calculates the local clock shift amount based on the monitoring result of the buffer amount, and instead calculates the time of the program packet taken out from the buffer 22, which is obtained via the selection section 41. The stamp value is compared with the value of the timestamp counter, and the amount of deviation of the local clock is calculated based on the comparison result. Here, the local clock deviation amount calculation unit 44 determines whether a null packet has been inserted in the multiplexing unit 3 of the broadcast wave IP transmission device 161 based on the time stamp difference between temporally consecutive program packets in the buffer 22. When comparing the timestamp value of the next program packet determined to have been inserted, the value of the timestamp counter is corrected by the amount of the null packet, and the corrected value is used for comparison (step S39). .

Next, the broadcast TS multiplexing unit 23 deletes the time stamp added to the extracted program packet according to the timing of the reproduction clock, and remultiplexes the deleted program packet into the broadcast TS frame (step S40).

Step S41 is similar to step S9 shown in FIG.

In Example 3 as well, the configuration using time stamps makes it possible to adjust the frequency of the local clock as in Examples 1 and 2; The effect of frequency adjustment can be obtained in common.

As explained in Examples 1 to 3, in the broadcast retransmission system 301, the transmission rate of the stream can be lowered by the configuration in which the PID filter 2 of the station side device 101 deletes each TS packet in the A layer for One Seg. Therefore, by a simple process of appropriately inserting null packets in each multiplexer 3, the transmission rate of the stream in each channel can be made equal, without adjusting to the channel with the lowest transmission rate among the channels, and the transmission rate can be The degree of freedom in rate setting can be increased.

Further, since the number of layers subject to modulation processing in the OFDM modulation section 24 can be reduced, the circuit scale can be reduced.

By the way, for example, when performing an IP retransmission service that transmits received broadcast waves to homes via an IP network, it is necessary to store the packets included in the broadcast waves in IP packets and retransmit them to each home. Conceivable. A better technique for performing such retransmissions is desired.

In the broadcast retransmission system according to the first embodiment of the present disclosure, the station-side device 101 receives broadcast waves containing program information, and transmits broadcast IP packets synchronized with a reference clock that store the program information. Generate and send. The home device 202 receives broadcast IP packets transmitted from the station device 101, measures the reception rate of the broadcast IP packets, and reproduces the reference clock by adjusting its own clock based on the measured reception rate. Then, using the reproduced clock, which is the reproduced reference clock, a broadcast wave containing information about the program is output.

In the station-side device according to the first embodiment of the present disclosure, the tuner 1 receives broadcast waves containing program information. The transmitting unit 12 performs a transmission process of generating and transmitting an IP packet synchronized with a reference clock, which stores information about a program included in the broadcast wave received by the tuner 1. In the transmission process, the transmitter 12 generates an IP packet whose reference clock can be recognized by the home device 202 to which the IP packet is transmitted.

In the home-side device according to the first embodiment of the present disclosure, the IP receiving unit 31 receives from the station-side device 101 an IP packet synchronized with a reference clock that stores information about a program included in a broadcast wave. The reproducing unit 33 reproduces the reference clock using information received by the IP receiving unit 31 and given in the IP packet transmission process in the station-side device 101. The transmitting unit 32 outputs a broadcast wave containing information on the program using a reproduced clock that is a reference clock reproduced by the reproducing unit 33.

In the broadcast retransmission method according to the first embodiment of the present disclosure, the station-side device 101 first generates an IP packet synchronized with a reference clock that stores program information included in the received broadcast wave. Send. Next, the home device 202 measures the reception rate of IP packets transmitted from the station device 101, and adjusts its own clock based on the measured reception rate to reproduce the reference clock. Next, the home device 202 outputs a broadcast wave containing information about the program using the reproduced clock that is the reproduced reference clock.

With such a configuration, for example, broadcast waves can be transmitted to the home side via the same transmission path as IP packets related to services other than broadcasting, so the network configuration between the station side and the home side can be simplified. can. For example, when connecting the central office side and the residential side using optical fiber, it is possible to suppress the increase in equipment for amplifying optical signals, etc., and to ensure transmission quality compared to a configuration that uses wavelength multiplexing. The transmission distance can be extended at the same time.

Therefore, in the broadcast retransmission system, station side device, home side device, and broadcast retransmission method according to the first embodiment of the present disclosure, an excellent system for retransmitting broadcast waves to the home side via a network is constructed. can do.

Next, other embodiments of the present disclosure will be described using the drawings. In addition, the same reference numerals are attached to the same or corresponding parts in the drawings, and the description thereof will not be repeated.

<Second embodiment>
This embodiment relates to a broadcast retransmission system that directly retransmits broadcast waves, compared to the broadcast retransmission system according to the first embodiment. The contents other than those described below are the same as the broadcast retransmission system according to the first embodiment.

FIG. 9 is a diagram showing the configuration of a broadcast retransmission system according to the second embodiment of the present disclosure.

Referring to FIG. 9, broadcast retransmission system 302 includes a plurality of station-side devices 111, OLT 151, D-ONU 152, VDSL device 153, and home-side device 212.

The station-side device 111 and the OLT 151 are installed, for example, in a station building of an operator that provides cable television broadcasting. The D-ONU 152, the VDSL device 153, and the home device 212 are provided in, for example, an apartment complex.

The station-side device 111 receives broadcast waves including streams, for example. The broadcast wave is, for example, a broadcast wave other than terrestrial digital broadcasting. The bandwidth of the broadcast wave is, for example, 70 MHz or more. Further, each station side device 111 is supplied with a common station side clock. Note that any one station-side device 111 may generate a station-side clock and supply it to each other station-side device 111. The frequency of the station-side clock is, for example, 10 MHz.

The station-side device 111 generates a broadcast IP packet containing information on the received broadcast wave and transmits it to the OLT 151.

The OLT 151 is an example of a multiplexing device, and receives broadcast IP packets received from each station side device 111 and other IP packets received from an upper network such as the Internet, and processes the received broadcast IP packets and other IP packets. Multiplex and transmit. More specifically, OLT 151 generates an optical signal containing each IP packet and transmits it to one or more D-ONUs 152 via an optical network including optical fiber 251.

The D-ONU 152 is an example of a demultiplexing device, and acquires IP packets included in the optical signal received from the OLT 151, and divides each acquired IP packet based on the destination IP address or port number of the acquired IP packet. is divided into broadcast IP packets and other IP packets and output. The D-ONU 152 transmits broadcast IP packets to the home device 212 and other IP packets to the VDSL device 153.

The home device 212 generates a broadcast wave containing the information of the broadcast IP packet received from the D-ONU 152, and outputs it to each TV monitor 91 in an apartment complex, for example, via an antenna line. The home device 212 generates and outputs broadcast waves without performing modulation processing.

The TV monitor 91 reproduces programs based on the audio information and video information included in the broadcast waves received from the home device 212.

The VDSL device 153 generates a communication signal containing other IP packets received from the D-ONU 152, and transmits it to the home device 92, such as a personal computer, via a telephone line.

Note that the broadcast retransmission system 302 is not limited to an apartment complex, and may be configured to transmit broadcast waves to a plurality of single-family houses and transmit other IP packets, for example, to prevent viewing difficulties.

FIG. 10 is a diagram showing the configuration of a station-side device in a broadcast retransmission system according to a second embodiment of the present disclosure.

Referring to FIG. 10, station-side device 111 includes a receiving section 51 and a transmitting section 52. The transmitter 52 includes an A/D converter 61, an IP transmitter 62, and a clock generator 63.

The station-side device 111 generates and transmits a broadcast IP packet synchronized with a reference clock, which stores program information.

More specifically, the receiving unit 51 receives broadcast waves containing program information. The receiving section 51 outputs broadcast waves received from, for example, an antenna (not shown) to the A/D converter 61 in the transmitting section 52.

The transmitting unit 52 performs a transmission process of generating and transmitting a broadcast IP packet synchronized with a reference clock, which stores program information included in the broadcast wave received by the receiving unit 51.

More specifically, the A/D converter 61 operates according to the timing of the reference clock received from the clock generator 63 and converts the broadcast wave, which is an analog signal received from the receiving section 51, into a digital signal and sends it to the IP transmitting section 62. Output.

The clock generator 63 generates a reference clock by frequency-dividing or multiplying the received station-side clock, and outputs it to each circuit such as the A/D converter 61.

The IP transmitter 62 generates a broadcast IP packet in which the digital signal received from the A/D converter 61 is stored in the payload, and transmits it to the OLT 151 .

Here, since the common station clock is supplied to each station side device 111 as described above, each station side device 111 can more accurately output broadcast waves that are synchronized with each other and have the same transmission rate. Can be done.

FIG. 11 is a diagram showing the configuration of a home device in a broadcast retransmission system according to a second embodiment of the present disclosure.

Referring to FIG. 11, home device 212 includes an IP receiving section 71, a transmitting section 72, and a reproducing section 73. Transmitting section 72 includes a buffer 81 and a D/A converter 82. The reproduction section 73 includes a buffer amount monitoring section 83 , a buffer amount increase/decrease time measuring section 84 , a local clock deviation amount calculation section 85 , a local clock control section 86 , and a local clock generation section 87 .

The home device 212 receives the broadcast IP packets transmitted from the station device 111, measures the reception rate of the broadcast IP packets, and reproduces the reference clock by adjusting its own clock based on the measured reception rate. do. Then, the home device 212 outputs a broadcast wave containing information about the program using the reproduced clock that is the reproduced reference clock.

In the home device 212, the IP receiving unit 71 receives from the station device 111 a broadcast IP packet that is synchronized with a reference clock and stores information about a program included in the broadcast wave.

The transmitting unit 72 outputs a broadcast wave containing information on the program using a reproduced clock that is a reference clock reproduced by the reproducing unit 73.

More specifically, the IP receiving unit 71 stores the broadcast IP packets received from the D-ONU 152 in the buffer 81.

The D/A converter 82 extracts the broadcast IP packet from the buffer 81 in accordance with the timing of the reproduction clock received from the reproduction section 73, converts it into an analog signal, and outputs it to the antenna line as a broadcast wave.

The reproducing unit 73 reproduces the reference clock using information given in the broadcast IP packet transmission process in the station-side device 111.

More specifically, the buffer amount monitoring section 83 monitors the buffer amount, that is, the amount of data accumulated in the buffer 81, and outputs the monitoring result to the buffer amount increase/decrease time measuring section 84.

The buffer amount increase/decrease time measuring section 84 measures the increase/decrease time of the storage amount in the buffer 81 based on the monitoring result of the buffer amount monitoring section 83 . For example, the buffer amount increase/decrease time measuring unit 84 holds a first threshold value that is larger than the reference value of the buffer amount and a second threshold value that is smaller than the reference value of the buffer amount. The time until it becomes less than the threshold is measured, and the measurement result is output to the local clock deviation amount calculation unit 85.

The local clock deviation amount calculation unit 85 calculates the deviation amount of the local clock based on the measurement result received from the buffer amount increase/decrease time measurement unit 84 and outputs the calculation result to the local clock control unit 86.

The local clock control unit 86 outputs a control signal to the local clock generation unit 87 according to the calculation result received from the local clock deviation amount calculation unit 85, thereby adjusting the frequency of the local clock output from the local clock generation unit 87. adjust. This changes the speed at which the D/A converter 82 takes out broadcast IP packets from the buffer 81.

For example, the local clock control unit 86 changes the frequency of the local clock at a predetermined resolution so that the buffer amount of the buffer 81 converges to the reference value. For example, the local clock control unit 86 repeats the operation of changing the frequency of the local clock by the adjustment amount closest to the deviation amount indicated by the above calculation result.

The local clock generation section 87 outputs a local clock whose frequency is set according to the control signal received from the local clock control section 86 to the D/A converter 82 as a reproduced clock.

In this way, in the broadcast retransmission system 302, like the broadcast retransmission system 301, the clock is regenerated at a predetermined resolution based on the bit rate on the transmitting side, so that, for example, the accuracy of the regenerated clock with respect to the reference clock is A realistic value of ±0.3 ppm can be achieved from the viewpoint of hardware configuration. This eliminates the need for an expensive high-precision oscillator in the home device 212.

Other configurations and operations are the same as those of the broadcast retransmission system according to the first embodiment, so detailed explanations will not be repeated here.

Although the broadcast retransmission systems 301 and 302 have a configuration in which broadcast waves are converted into optical signals and transmitted, the present invention is not limited to this. The broadcast retransmission systems 301 and 302 may be configured to transmit IP packets containing broadcast waves, and may be configured to use a network different from an optical network.

The above embodiments should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

The above description includes the features noted below.
[Additional note 1]
a station-side device that receives a broadcast wave containing program information, generates and transmits an IP packet synchronized with a reference clock that stores the program information;
Receive the IP packets transmitted from the station-side device, measure the reception rate of the IP packets, and reproduce the reference clock by adjusting its own clock based on the measured reception rate. and a home-side device that outputs broadcast waves containing information on the program using the reproduced clock that is the reference clock,
The home device detects the channels in use and measures the reception rate on any one of the detected channels,
The home device generates a frame storing information of the program included in the IP packet for each channel using the reproduced clock, and multiplexes and modulates the frames of the plurality of generated channels. The modulated signal is output as a broadcast wave,
The station-side device adjusts the transmission rate in each channel to be the same by selecting whether to insert a null packet between a plurality of program packets in which the program information is divided and stored;
In the transmission process, the station-side device performs a process of providing the home-side device with information used when regenerating the reference clock in the home-side device to which the IP packet is transmitted;
The station-side device generates IP packets using null packets or time stamps so that the transmission rate of the stream becomes the same set bit rate in the station-side device and the home-side device.

[Additional note 2]
a receiving unit that receives broadcast waves containing program information;
a transmitting unit that performs a transmission process of generating and transmitting an IP packet synchronized with a reference clock that stores information about the program included in the broadcast wave received by the receiving unit;
In the transmission process, the transmitter generates the IP packet so that the reference clock can be recognized by a home device to which the IP packet is transmitted;
The transmission unit adjusts the transmission rate in each channel to be the same by selecting whether to insert a null packet between a plurality of program packets in which the program information is divided and stored;
In the transmission process, the transmitter performs a process of providing the home device with information used when regenerating the reference clock in the home device that is the destination of the IP packet,
The transmission unit is a station-side device that generates an IP packet using a null packet or a time stamp so that the transmission rate of the stream becomes the same set bit rate in the station-side device and the home-side device.

[Additional note 3]
a receiving unit that receives from a station-side device an IP packet synchronized with a reference clock that stores program information included in the broadcast wave;
a reproduction unit that reproduces the reference clock using information received by the reception unit and given in the transmission processing of the IP packet in the station-side device;
a transmitter that outputs a broadcast wave containing information about the program using a reproduced clock that is the reference clock reproduced by the reproducer;
The reproducing unit detects the channels in use and measures the reception rate on any one of the detected channels,
The transmitting unit generates a frame storing information of the program included in the IP packet for each channel using the reproduced clock, and multiplexes and modulates the generated frames of the plurality of channels. A home-side device that outputs modulated signals as broadcast waves.

1 Tuner 2 PID filter 3 Multiplexing section 4 IP transmitting section 12 Transmitting section 21 Packet filter 22 Buffer 23 Broadcast TS multiplexing section 24 OFDM modulating section 25 Mixing circuit 31 IP receiving section 32 Transmitting section 33 Reproducing section 51 Receiving section 52 Transmitting section 61 A/D converter 62 IP transmitter 63 Clock generator 101, 111 Station side device 151 OLT
152 D-ONU
153 VDSL device 161 Broadcast wave IP transmission device 202, 212 Home side device 301, 302 Broadcast retransmission system

Claims (7)

a station-side device that receives a broadcast wave containing program information, generates and transmits an IP packet synchronized with a reference clock that stores the program information;
Receive the IP packets transmitted from the station-side device, measure the reception rate of the IP packets, and reproduce the reference clock by adjusting its own clock based on the measured reception rate. and a home-side device that outputs broadcast waves containing information on the program using the reproduced clock that is the reference clock,
The station-side device generates the IP packet for each channel of digital terrestrial broadcasting, multiplexes and transmits the generated IP packets of the plurality of channels,
In the broadcast retransmission system, the home device selects any one of the plurality of channels and measures the reception rate of the selected channel. The station-side device generates a program packet, which is a plurality of TS (Transport Stream) packets in which information about the program is divided and stored, and adjusts the transmission rate by inserting a null packet between the program packets. , storing the adjusted program packet and the null packet in the IP packet and transmitting it;
The home device stores the program packet and the null packet stored in the received IP packet in a buffer, monitors the amount of storage in the buffer, and adjusts the frequency of its own clock based on the amount of storage. The broadcast retransmission system according to claim 1. The station-side device generates a plurality of TTS (Timestamped Transport Stream) packets in which information about the program is divided and stored, stores the generated TTS packet in the IP packet, and transmits the packet,
The broadcast retransmission system according to claim 1, wherein the home device adjusts the frequency of its own clock based on a time stamp in the TTS packet stored in the received IP packet. a station-side device that receives a broadcast wave containing program information, generates and transmits an IP packet synchronized with a reference clock that stores the program information;
a multiplexing device that multiplexes and transmits the broadcast IP packet, which is the IP packet transmitted from the station-side device, and other IP packets received from the network;
a demultiplexer that receives the IP packet transmitted from the multiplexer and outputs the broadcast IP packet and the other IP packets separately;
Regenerating the reference clock by receiving the broadcast IP packets output from the demultiplexer, measuring the reception rate of the broadcast IP packets, and adjusting its own clock based on the measured reception rate. A broadcast retransmission system comprising: a home-side device that outputs a broadcast wave containing information about the program using a reproduced clock that is the reproduced reference clock. A home-side device,
a receiving unit that receives from a station-side device an IP packet synchronized with a reference clock that stores program information included in the broadcast wave;
a reproduction unit that reproduces the reference clock using information received by the reception unit and given in the transmission processing of the IP packet in the station-side device;
a transmitter that outputs a broadcast wave containing information about the program using a reproduced clock that is the reference clock reproduced by the reproducer;
The station-side device generates the IP packet for each channel of digital terrestrial broadcasting, multiplexes and transmits the generated IP packets of the plurality of channels,
The home device selects any one of the plurality of channels, measures the reception rate of the IP packets on the selected channel, and adjusts its own clock based on the measured reception rate. A home-side device that reproduces the reference clock by adjusting it. A broadcast retransmission method in a broadcast retransmission system, comprising:
a step in which the station-side device generates and transmits an IP packet synchronized with a reference clock that stores program information included in the received broadcast wave;
a step in which the home-side device measures the reception rate of the IP packets transmitted from the station-side device and adjusts its own clock based on the measured reception rate, thereby regenerating the reference clock;
the home device outputs a broadcast wave containing information about the program using a reproduced clock that is the reproduced reference clock;
In the step of generating and transmitting the IP packet, the station-side device generates the IP packet for each channel of digital terrestrial broadcasting, multiplexes and transmits the generated IP packets of the plurality of channels,
In the step of regenerating the reference clock, the home device selects any one of the plurality of channels and measures the reception rate of the selected channel. A broadcast retransmission method in a broadcast retransmission system, comprising:
a step in which the station-side device generates and transmits an IP packet synchronized with a reference clock that stores program information included in the received broadcast wave;
a multiplexing device multiplexing and transmitting the broadcast IP packet, which is the IP packet transmitted from the station-side device, and other IP packets received from the network;
a demultiplexing device receives the IP packet transmitted from the multiplexing device, and outputs the divided IP packet into the broadcast IP packet and the other IP packet;
The home device receives the broadcast IP packets output from the demultiplexer, measures the reception rate of the broadcast IP packets, and adjusts its own clock based on the measured reception rate. regenerating the reference clock;
A broadcast retransmission method comprising the step of the home-side device outputting a broadcast wave containing information on the program using a reproduced clock that is the reproduced reference clock.

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