JP2018157521A - System and method for transmission of cable television signals including advanced broadband satellite broadcasting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long distance transmission of cable television signals including advanced broadband satellite broadcasting.SOLUTION: The system includes a primary broadcasting station, a secondary broadcasting station, and a reception station. The secondary broadcast station includes a first tuner and a first transmission IP packet processing unit. The primary broadcast station includes a first reception IP packet processing unit, a second tuner, an up-converter, a mixer, and a second transmission IP packet processing unit. The reception station includes a second reception IP packet processing unit, a digital/analog conversion circuit, and an output unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmission system and method for cable television signals including advanced broadband satellite broadcasting.

  In recent years, an increasing number of cable television stations adopt a central casting system for the purpose of consolidating broadcasting facilities and reducing costs. The central casting system is a system in which one master station is determined in a block of a broadcast reception area, and broadcast transmission between affiliate stations is collectively managed by the master station. That is, the broadcasting facilities are collected at the master station in the block. On the other hand, there is an aspect that the transmission distance becomes longer due to the increase in the degree of integration of the broadcasting equipment.

  In addition, a television service using an RF (Radio Frequency) signal performs analog transmission by an electrical signal on a coaxial cable or direct or external light intensity modulation using an optical fiber.

  In the future, 4K / 8K broadcasting using left-handed circularly polarized waves is scheduled from BS satellites and 110-degree CS satellites (hereinafter referred to as advanced broadband satellite broadcasting). Such satellite broadcasts are generally converted to an intermediate frequency (hereinafter referred to as IF) and transmitted so that they can be received as they are by a compatible television. The IF of the left circular polarization of the BS satellite is 2,224 to 2,681 MHz, and the IF of the left circular polarization of the CS satellite is 2,748 to 3,224 MHz (see Non-Patent Document 1).

“Follow-up Meeting on 4K / 8K Roadmap Second Interim Report Reference Materials”, Ministry of Internal Affairs and Communications, July 30, 2015, p. 45, <URL: http://www.soumu.go.jp/main_content/000370907.pdf>

  The IF of advanced broadband satellite broadcasting is a signal having a frequency higher than that of conventional broadcasting waves. Such signals have a large signal loss when analog transmission is performed by an electrical signal through a coaxial cable, and signal loss is small when analog transmission is performed directly or by external light intensity modulation using an optical fiber. It is necessary to arrange optical fiber amplifiers at short intervals. Therefore, broadcast waves including IF of advanced broadband satellite broadcasting have a problem that it is difficult to transmit over a long distance while maintaining viewable quality.

  As a measure for solving the situation where long-distance transmission is difficult, it is conceivable to install a broadcast wave reception point and a transmission apparatus closer to the customer side (for example, each station in the area) to shorten the transmission distance. However, there are problems that the transmission apparatus is expensive and that maintenance and maintenance that suppresses the bias of each station due to transmission characteristics requires personnel and skills to visit and adjust each station.

  Further, as described above, it is more difficult to manage broadcast waves that can be received in each area by collectively managing broadcast transmission at a master station or the like. This is because each broadcast wave has a limited receivable area, and the parent station needs to consider the transmission characteristics of each station. For example, a broadcast wave received by a master station in X prefecture is transmitted in common to A city, B city, and C city, and A city further transmits a terrestrial digital television broadcast that can be received only in A city. The frequency and output allocated by the plan may vary from region to region. For this reason, the master station in X prefecture needs to manage the broadcast waves of A city and the broadcast waves of B city and C city separately.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide long-distance transmission of cable television signals including advanced broadband satellite broadcasting. More specifically, as a transmission method independent of distance, a received broadcast wave is converted into an IP packet and transmitted to a receiving station installed on the customer side, and the broadcast wave is reproduced at the receiving station and transmitted to a customer.

  In order to solve the above-described problems, a cable television signal transmission system including an advanced broadband satellite broadcast according to the present invention is provided for a cable television signal including an advanced broadband satellite broadcast including a primary broadcast station, a secondary broadcast station, and a receiving station. A transmission system, wherein a secondary broadcast station receives a first broadcast wave and selectively performs quadrature demodulation on the received first broadcast wave to generate a first broadcast wave signal. And a first transmission IP packet processing unit that generates and transmits a first IP packet from the first broadcast wave signal, and the primary broadcast station receives and receives the first IP packet from the secondary broadcast station. A first received IP packet processor for extracting a first broadcast wave signal from the first IP packet, and a second broadcast wave received and selectively directly received with respect to the received second broadcast wave. A second tuner for demodulating and generating a second broadcast wave signal; an upconverter for converting the extracted first broadcast wave signal and the generated second broadcast wave signal into a digital signal of an arbitrary frequency; A mixer that selectively mixes digital signals of an arbitrary frequency, and a second transmission IP packet processing unit that generates and transmits a second IP packet from the digital signal. A second received IP packet processing unit that receives the second IP packet and extracts a digital signal from the received second IP packet; a digital / analog conversion circuit that converts the digital signal into an analog signal; An output unit is provided that outputs an electrical signal or converts it into an optical signal and outputs it.

  According to the present invention, it is possible to shorten the analog transmission distance from the receiving station to the customer's home, etc., and to transmit the broadcast wave received at the secondary broadcast station to the primary broadcast station by IP transmission. High-quality signals can be transmitted to customers even at high frequencies.

  In addition, long-distance transmission using IP packets is realized for all cable television signals including advanced broadband satellite broadcasting.

  Furthermore, since necessary personnel and advanced skills can be concentrated on the primary broadcasting station side, it contributes to a reduction in work man-hours and costs, and maintenance costs are reduced.

  Furthermore, since the device installed on the customer side can be a simplified and inexpensive device, the cost is reduced even when installed in a wide range of receiving stations.

It is a figure which illustrates the outline | summary of the system configuration | structure concerning one Embodiment of this invention. It is a flowchart which illustrates the flow of the process concerning one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same number is attached | subjected to the same element through the whole description of embodiment.

  FIG. 1 is a diagram illustrating an outline of a system configuration according to an embodiment of the present invention. FIG. 1 schematically shows that a primary broadcasting station 100, a secondary broadcasting station 120, and a receiving station 130 are connected via an Ethernet (registered trademark) relay network, and a receiving station 130 and a customer residence are connected via a CATV relay network. It is illustrated that.

  The primary broadcast station 100 is a broadcast station that manages a plurality of distribution areas and intensively processes broadcast wave signals. The secondary broadcast station 120 is a broadcast station installed in each distribution area managed by the primary broadcast station 100. The receiving station 130 is a receiving station 130 that receives the IP packet transmitted by the primary broadcasting station 100 and converts it into a broadcast wave signal. Note that the secondary broadcast station 120 and the distribution area do not necessarily have a one-to-one relationship, and may be one-to-many or many-to-one. Further, the secondary broadcasting station 120 and the receiving station 130 may be the same equipment.

(Primary broadcasting station configuration)
The primary broadcast station 100 is a broadcast station that manages a plurality of distribution areas and intensively processes broadcast wave signals. The primary broadcasting station 100 can receive digital broadcasting waves of a system such as ATSC (Advanced Television Systems Committee standard), DVB (Digital Video Broadcasting), ISDB (Integrated Services Digital Broadcasting). Further, the primary broadcast station 100 converts IP packets received from the secondary broadcast station 120 described below into broadcast waves. Then, these broadcast waves are up-converted to a frequency determined for each area, and a signal in which only the necessary broadcast waves are mixed for each area is converted into an IP packet and transmitted to the receiving station 130. Thereby, the adjustment of the broadcast wave can be performed for each area. The primary broadcast station 100 includes a tuner 102, a received IP packet processing unit 104, an up converter 106, a mixer 108, an analog / digital conversion circuit 110, and a transmission IP packet processing unit 112.

  The tuner 102 receives a broadcast wave from the antenna facility, selectively performs orthogonal demodulation on the broadcast wave to be received, and generates an I / Q signal. The broadcast wave to be received is, for example, a signal modulated by FM, OFDM, 64QAM (256QAM), TC8PSK / BPSK, 16APSK, or the like, and may include a signal of advanced broadband satellite broadcasting. The quadrature demodulation can be performed on a channel basis, for example, by filtering the frequency with a band pass filter. The quadrature demodulation can also be performed in units of a plurality of channels or in units of bands, and a circuit for performing channel separation may be provided at the subsequent stage of the analog / digital conversion circuit 110 described later.

  The received IP packet processing unit 104 receives an IP packet from the secondary broadcast station 120 via the Ethernet (registered trademark) relay network, and extracts an I / Q signal. The received IP packet processing unit 104 complements the IP packet from the RTP sequence number even when the IP packet is lost by adopting a redundant configuration conforming to, for example, SMPTE 2022-7 (Seamless Protection Switching of SMPTE ST 2022 IP Datagrams). can do. Here, for easy understanding, the I / Q signal generated by the tuner 102 is referred to as a broadcast wave derivation I / Q signal, and the I / Q signal generated by the reception IP packet processing unit 104 is derived as an IP packet. This is called an I / Q signal.

  As will be described later, each secondary broadcast station 120 receives a broadcast wave in the target distribution area and generates an IP packet based on the broadcast wave. Therefore, the IP packet derivation I / Q signal is the secondary broadcast station 120. It becomes a broadcast wave signal that can be received by the distribution area corresponding to.

  The up-converter 106 up-converts the broadcast wave derived I / Q signal and the IP packet derived I / Q signal to frequencies according to a channel plan determined for each distribution area. At this time, when the channel plan is different for each distribution area, the broadcast wave derived I / Q signal or IP packet derived I / Q signal and the frequency after up-conversion have a one-to-many relationship. For example, if tuner 102 receives C52ch and the channel plan corresponding to C52ch is defined as C17ch in distribution area A and C21ch in distribution area B, it can be upconverted to C17ch and C21ch, respectively. The upconverter 106 can also process either analog or digital signals.

  Mixer 108 mixes the upconverted signal. The mixer 108 can use an arbitrary frequency selected for each channel plan, which is desired to be created for each distribution area, as an input signal to the mixer 108, and can use the mixer 108 according to the number of channel plans. The mixer 108 can also process either analog or digital signals.

  The analog / digital conversion circuit 110 converts an analog signal into a digital signal. Conversion to a digital signal can be performed for the entire frequency band. In another embodiment, the analog / digital conversion circuit 110 can also perform conversion into a digital signal by dividing the frequency band into 500 MHz, 1 GHz, or the like. The processing for the divided frequency bands can reduce the required processing performance compared to the processing for all the frequency bands, so that the circuit can be simplified and inexpensive. The analog / digital conversion circuit 110 can be dispensed with when the upconverter 106 and the mixer 108 process digital signals.

  The transmission IP packet processing unit 112 converts the converted digital signal into an IP packet, and then transmits the IP packet to the reception station 130 via the Ethernet (registered trademark) relay network. Conversion to an IP packet is realized by being encapsulated by a protocol such as RTP (Real-time Transport Protocol) or UDP (User Datagram Protocol).

(Configuration of secondary broadcasting station)
The secondary broadcast station 120 is installed at each site where each broadcast wave where the broadcastable area is limited is distributed, and is a point that receives each broadcast wave. The secondary broadcast station 120 converts each received broadcast wave into an IP packet and transmits it to the primary broadcast station 100. The secondary broadcast station 120 includes a tuner 122 and a transmission IP packet processing unit 124.

  Since the tuner 122 is the same as the tuner 102 of the primary broadcast station 100 described above, the description thereof is omitted.

  The transmission IP packet processing unit 124 converts the I / Q signal generated by the tuner 122 into an IP packet, and then transmits the IP packet to the primary broadcast station 100 via the Ethernet (registered trademark) relay network. The conversion to the IP packet is realized by the method described in the transmission IP packet processing unit 112 of the primary broadcast station 100.

(Configuration of receiving station)
The receiving station 130 receives the IP packet transmitted from the primary broadcasting station 100 and converts it into a broadcast wave signal. The receiving station 130 extracts each broadcast wave signal from the received IP packet, and transmits the broadcast wave electrical signal or optical signal to the customer via the CATV relay network. The receiving station 130 includes a received IP packet processing unit 132, a digital / analog conversion circuit 134, and an output unit 138. Moreover, in another embodiment, the mixer 136 can be further provided. The receiving station 130 may be the same as the receiving station 130 as long as the processing described below is possible.

  The received IP packet processing unit 132 receives an IP packet from the primary broadcast station 100 via the Ethernet (registered trademark) relay network, and extracts a digital signal. For example, the reception IP packet processing unit 132 has a redundant configuration conforming to SMPTE 2022-7, so that the IP packet can be complemented from the RTP sequence number even when the IP packet is lost.

  A digital / analog conversion circuit (hereinafter referred to as DAC) 134 converts the extracted digital signal into an analog signal. The analog signal converted by the DAC 134 is obtained as an electric signal. In another embodiment, if the digital signal is split, a plurality of DACs 134 can be used to convert the digital signal to an analog signal. In this case, the mixer 136 can be used after the plurality of DACs 134 to perform mixing.

  The output unit 138 uses a signal obtained by the DAC 134 as an electric signal or a signal for driving a laser of an optical transmitter (direct modulation type optical transmitter), and transmits a broadcast wave to a customer. be able to.

  As described above, by using both IP transmission and analog transmission, long-distance transmission is possible for cable television signals including signals of advanced broadband satellite broadcasting.

  FIG. 2 is a flow diagram illustrating the flow of processing according to an embodiment of the present invention. Hereinafter, the process flow will be described separately for the secondary broadcast station, the primary broadcast station, and the receiving station. Here, the channel plan of City A will be described as C1ch, C2ch, C3ch, C4ch and C5ch, and the channel plan of City B and C city will be described as C1ch, C2ch and C3ch.

(Secondary broadcast station processing)
In step S201, the secondary broadcast station 120 receives a broadcast wave from the antenna facility by the tuner 122, selectively performs quadrature demodulation on the broadcast wave to be received, and generates an I / Q signal. For example, the secondary broadcasting station 120 installed in the city A receives a broadcast wave distributed only from the antenna facility to the city A by the tuner 122, selectively performs orthogonal demodulation on the broadcast wave to be received, I / Q signal is generated.

  In step S202, the secondary broadcast station 120 converts the I / Q signal into an IP packet by the transmission IP packet processing unit 124.

  In step S <b> 203, the secondary broadcast station 120 transmits the IP packet to the primary broadcast station 100 using the transmission IP packet processing unit 124.

(Primary broadcast station processing)
In step S204, the primary broadcast station 100 receives the IP packet from the secondary broadcast station 120 by the received IP packet processing unit 104, and extracts the IP packet derivation I / Q signal. The primary broadcast station 100 can process broadcast waves that can be received only in the area where the secondary broadcast station 120 is installed, by the IP packet derivation I / Q signal. Further, the primary broadcast station 100 receives a broadcast wave from the antenna facility by the tuner 102, selectively performs orthogonal demodulation on the broadcast wave to be received, and generates a broadcast wave derived I / Q signal. The extraction of the IP packet derived I / Q signal and the generation of the broadcast wave derived I / Q signal may be performed in parallel regardless of time.

  In step S205, the primary broadcast station 100 uses the up-converter 106 to up-convert the broadcast wave derived I / Q signal and the IP packet derived I / Q signal to frequencies according to a channel plan determined for each distribution area. For example, it is possible to up-convert to frequencies in accordance with channel plans C1ch, C2ch, and C3ch of company B and company C.

  In step S <b> 206, the primary broadcast station 100 mixes the up-converted signal by the mixer 108. A plurality of mixed signals may be generated according to the number of channel plans. For example, the channel plans for B city and C city can mix C1ch, C2ch and C3ch, and the channel plan for A city can mix C1ch, C2ch, C3ch, C4ch and C5ch.

  In step S207, the primary broadcast station 100 converts the analog signal into a digital signal by the analog / digital conversion circuit 110. Here, when digital signal processing is performed in step S205 and step S206, the processing in step S207 is not necessary.

  In step S <b> 208, the primary broadcast station 100 converts the digital signal into an IP packet by the transmission IP packet processing unit 112.

  In step S <b> 209, the primary broadcast station 100 transmits the IP packet to the receiving station 130 by the transmission IP packet processing unit 112.

(Receiving station processing)
In step S210, the receiving station 130 receives an IP packet from the primary broadcast station 100 by the received IP packet processing unit 132, and extracts a digital signal. The digital signal to be extracted may be different between the receiving station 130 in City A and the receiving station 130 in City B. For example, the receiving station 130 in City A may extract digital signals including C1ch, C2ch, C3ch, C4ch, and C5ch, and the receiving station 130 in City B may extract digital signals including C1ch, C2ch, and C3ch. .

  In step S211, the receiving station 130 determines whether the digital signal is divided. The division of the digital signal can be determined based on, for example, whether or not data indicating division is stored in the overhead data.

  In step S212 (NO in step S211), the receiving station 130 converts the digital signal into an analog signal by the DAC 134.

  In step S215, the receiving station 130 transmits a broadcast wave electrical signal or optical signal to the customer.

  By doing in this way, it is possible to manage broadcast waves received by the primary broadcast station 100 and broadcast waves with limited distribution areas received by the secondary broadcast station 120 according to the distribution area. Further, by simplifying the processing of the receiving station 130, a device installed in the receiving station 130 can be a simplified and inexpensive device. Furthermore, since transmission from the secondary broadcast station 120 to the primary broadcast station 100 and transmission from the primary broadcast station to the receiving station 130 are performed by IP transmission, long-distance transmission is possible.

  Furthermore, in another embodiment, it demonstrates using FIG. Since steps S201 to S206, steps S208 to S211 and step S215 are the same as described above, the description thereof will be omitted.

  In step S207, the primary broadcast station 100 converts the analog signal into a digital signal by the analog / digital conversion circuit 110. At this time, for example, the signal is divided into frequency bands such as 500 MHz and 1 GHz, and converted into a digital signal. By dividing and processing the frequency band, the processing performance required for the analog / digital conversion circuit 110 can be relaxed, and the circuit can be simplified and inexpensive.

  In step S213 (in the case of YES in step S211), the receiving station 130 converts the digital signal into an analog signal by the plurality of DACs 134. By dividing and processing the frequency band, the processing performance required for the plurality of DACs 134 is alleviated, and the circuit can be simplified and inexpensive.

  In step S214 (in the case of YES in step S211), the receiving station 130 mixes all the analog signals obtained in step S213 by the mixer 136. Since the channel plan is controlled by the primary broadcasting station 100 and there is no need to consider the unit of mixing in the receiving station 130, the processing of the receiving station 130 is simplified, and the apparatus installed in the receiving station 130 is simplified. A cheaper device.

  The embodiments disclosed in this specification and the drawings are merely examples, and should not be construed as being limited to the contents of the present disclosure when defining the technical scope of the present invention. Although each process is described separately for the sake of explanation, the processes may be implemented so that the processes are integrated and linked, and the other part performs all or part of the processes included in each process.

Claims (5)

A cable television signal transmission system including an advanced broadband satellite broadcasting composed of a primary broadcasting station, a secondary broadcasting station, and a receiving station,
The secondary broadcast station is
A first tuner that receives a first broadcast wave, selectively performs orthogonal demodulation on the received first broadcast wave, and generates a first broadcast wave signal;
A first transmission IP packet processing unit for generating and transmitting a first IP packet from the first broadcast wave signal;
The primary broadcast station is
A first received IP packet processing unit that receives the first IP packet from the secondary broadcast station and extracts the first broadcast wave signal from the received first IP packet;
A second tuner that receives a second broadcast wave, selectively performs orthogonal demodulation on the received second broadcast wave, and generates a second broadcast wave signal;
An up-converter that converts the extracted first broadcast wave signal and the generated second broadcast wave signal into a digital signal of a predetermined frequency;
A mixer for selectively mixing the digital signal of the predetermined frequency;
A second transmission IP packet processor for generating and transmitting a second IP packet from the mixed frequency digital signal;
The receiving station is
A second received IP packet processing unit that receives the second IP packet from the primary broadcast station and extracts the digital signal from the received second IP packet;
A digital / analog conversion circuit for converting the digital signal into an analog signal;
A system comprising: an output unit that outputs the analog signal as an electrical signal or converts the analog signal into an optical signal and outputs the optical signal. The up-converter converts the extracted first broadcast wave signal and the generated second broadcast wave signal into an analog signal having a predetermined frequency,
The mixer selectively mixes the analog signal of the predetermined frequency;
The system according to claim 1, further comprising an analog / digital conversion circuit for converting the mixed frequency analog signal into a digital signal. The analog / digital conversion circuit divides the mixed frequency signal into a digital signal by dividing the analog signal into arbitrary frequency bands,
The digital / analog conversion circuit is a plurality of digital / analog conversion circuits for converting the digital signal divided and converted for each arbitrary frequency band into a plurality of analog signals,
The system of claim 2, wherein the receiving station further comprises a mixer for mixing the plurality of analog signals. A method for carrying out a cable television signal transmission system including advanced broadband satellite broadcasting,
Receiving a first broadcast wave, selectively performing orthogonal demodulation on the received first broadcast wave to generate a first broadcast wave signal;
Generating and transmitting a first IP packet from the first broadcast wave signal;
Receiving the first IP packet and extracting the first broadcast wave signal from the received first IP packet;
Receiving a second broadcast wave, selectively performing orthogonal demodulation on the received second broadcast wave to generate a second broadcast wave signal;
Converting the extracted first broadcast wave signal and the generated second broadcast wave signal into a signal of an arbitrary frequency;
Selectively mixing the signals of any frequency;
Converting the mixed frequency signal from an analog signal to a digital signal;
Generating and transmitting a second IP packet from the digital signal;
Receiving the second IP packet and extracting the digital signal from the received second IP packet;
Converting the digital signal into the analog signal;
The method includes outputting the analog signal as an electric signal or converting the analog signal into an optical signal and outputting the optical signal. The conversion from the analog signal to the digital signal is to divide the mixed-frequency signal from the analog signal into an arbitrary frequency band and convert it into a digital signal,
Converting the digital signal to the analog signal is converting the converted digital signal into a plurality of analog signals by dividing each arbitrary frequency band,
The method of claim 4, further comprising mixing the plurality of analog signals.

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