JP2010124135A - Repeater and broadcast system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously repeat broadcast signals while expanding a broadcast area. <P>SOLUTION: A communication part 80 receives a communication signal with content data stored therein. A storage part 180 stores the content data stored in the received communication signal. A signal conversion part 162 stores the content data stored in the storage part 180 in a broadcast signal in a first-in and first-out manner, and broadcasts the broadcast signal. When the volume of the content date which are stored in the storage part 180 but not stored in the broadcast signal becomes smaller than the threshold value, the signal conversion part 162 repeatedly stores the content data stored in the storage part 180 into the broadcast signal and broadcasts the broadcast signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to relay technology, and more particularly, to a relay device that relays broadcast signals and a broadcast system using the relay device.

  In a broadcasting system such as a television broadcasting system, a signal is transmitted as an electromagnetic wave from a broadcasting station. The television broadcast receiver receives a signal transmitted from a broadcasting station and acquires image information, audio information, and the like from the received signal. With regard to signals transmitted by broadcast stations, provisions such as transmission power and desired signal-to-interference wave ratio are established so that information of a predetermined quality can be obtained in a television broadcast receiver in the area where the broadcast station is broadcast. It has been. However, even if a broadcasting station transmits a signal that satisfies the regulations, if there are electromagnetic wave obstacles or the like in the broadcasting area, the electric field strength of the signal received by the television broadcast receiver becomes insufficient. There are areas where information of a certain quality cannot be obtained. Therefore, in order to reduce such quality degradation areas, a relay apparatus that receives a signal transmitted from a broadcasting station, amplifies and transmits the signal is installed in the broadcasting area.

  For example, the relay device receives an analog modulated signal formed by a plurality of channels by a receiving antenna, and outputs the received signal to a duplexer. The duplexer separates the received signal into channels. That is, the duplexer outputs a signal obtained by attenuating a signal in a frequency band other than the desired channel. The duplexer outputs a plurality of signals to a plurality of in-channel band amplifying units. Each of the in-channel band amplifying units amplifies the channel unit signal, and then converts it to an intermediate frequency band signal. In addition, after band limitation for attenuating signals other than the desired channel is performed, amplification at the intermediate frequency is performed, and the signal is again converted to the broadcast frequency band and then amplified. The amplified signals are output to the multiplexer. The multiplexer combines a plurality of signals. The signal synthesized by the multiplexer is transmitted as an electromagnetic wave via the transmission antenna.

  Such a relay device separates a received signal into a plurality of channels, and individually performs band limitation and amplification on the frequency bands of the respective channels. This reduces as much as possible the interference wave caused by the intermodulation generated by the analog modulation signals of different channel frequency bands mutually affecting each other or the noise superimposed on the frequency band close to each channel frequency band. (For example, refer to Patent Documents 1 and 2). In recent years, digital television broadcasting that transmits information using a digitally modulated signal has been used, and an analog modulation signal and a digital modulation signal are mixed. Even in such a situation, the above-described relay device is used. In general, digital television broadcasting is composed of more channels than conventional television broadcasting. For this reason, in the above-described configuration, an in-channel band amplification unit corresponding to the number of channels is required. Therefore, as the number of channels increases, the circuit becomes a large-scale configuration and the manufacturing cost increases.

In order to solve this, a relay apparatus including a digital filter that can pass bands corresponding to a plurality of channels has been proposed. In addition, the digital filter is composed of a plurality of taps, and the coefficient corresponding to each of the plurality of taps is set to a variable value. Therefore, a tap coefficient that realizes a bandpass filter that passes through a channel to be relayed is set in the digital filter, so that the relay device can selectively relay a desired channel (see, for example, Patent Document 3). ).
JP 2000-324036 A JP 2007-288572 A JP 2007-043583 A

  If it is used for the relay device having the above configuration, the program can be viewed even in an area where it is difficult to receive a signal transmitted from a broadcasting station, such as in a building such as a house. However, if the installation location and usage method of such a relay device is wrong, there is a possibility that radio wave interference may occur with respect to the signal transmitted from the broadcasting station. Therefore, the degree of freedom of installation of the relay device is not great. On the other hand, in order to reduce the influence of radio wave interference, the power of the signal after relaying is designed to be weak. As a result, the area expanded by the relay device is about 1 to 2 mails, and the effect of area expansion by the relay device is reduced.

  Such a situation is the same when an organization other than a broadcaster broadcasts an independent program. For example, a program such as a store advertisement is broadcast in a limited area such as a shopping street or a shopping center. If the user already has an image receiving apparatus compatible with digital television broadcasting, the user can view the independent program without additional investment if the independent program supports digital television broadcasting. It is desired that the area where such an independent program is broadcast is also expanded without increasing the influence of radio wave interference. In such a television broadcasting system, in addition to expanding the area, continuous execution of relaying is also desired.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a technique for executing continuous relay while expanding a broadcast area.

  In order to solve the above problems, a relay apparatus according to an aspect of the present invention includes a receiving unit that receives a communication signal in which content data is stored, and a memory that stores the content data stored in the communication signal received in the receiving unit. And a broadcast unit that stores the content data stored in the storage unit in a first-in first-out manner into a broadcast signal and broadcasts the broadcast signal. The broadcast unit repeatedly stores the content data stored in the storage unit in the broadcast signal when the amount of data in the content data stored in the storage unit is smaller than the threshold value. Broadcast the broadcast signal.

  According to this aspect, since the communication signal is converted into a broadcast signal and transmitted, the area can be expanded, and the broadcast signal in which the content data is repeated when the amount of data in the unstored portion of the broadcast signal decreases. Since it transmits, continuous relay can be executed.

  The storage unit may store in advance content data to be repeatedly stored in the broadcast signal by the broadcast unit, separately from the content data stored in the communication signal received by the reception unit. In this case, content data to be repeatedly stored in the broadcast signal is stored separately, so that the length of the content data can be freely designed.

  Another aspect of the present invention is also a relay device. The apparatus includes a receiving unit that receives a communication signal in which content data is stored, a storage unit that stores content data stored in the communication signal received by the receiving unit, and content data stored in the storage unit in a first-in first-out manner. And a broadcast unit that stores the broadcast signal and broadcasts the broadcast signal. When the reception state of the communication signal in the reception unit deteriorates, the broadcast unit stores that fact in the broadcast signal and broadcasts the broadcast signal.

  According to this aspect, since the communication signal is converted into a broadcast signal and transmitted, the area can be expanded, and when the reception state of the communication signal deteriorates, the fact is broadcast so that the cause of the failure can be easily notified. .

  Yet another embodiment of the present invention is a broadcasting system. The broadcasting system includes a communication device that transmits a communication signal in which content data is stored, a communication signal from the communication device, the content data stored in the received communication signal is stored in a memory, and the memory And a relay device for storing the content data stored in the broadcast signal in a first-in first-out manner and broadcasting the broadcast signal. The relay device repeatedly stores the content data stored in the memory in the broadcast signal when the data amount of the portion not stored in the broadcast signal of the content data stored in the memory becomes smaller than the threshold value. Broadcast the signal.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, continuous relay can be executed while expanding a broadcast area.

  Before describing the present invention in detail, an outline will be described. An embodiment of the present invention relates to a broadcasting system for transmitting a signal (hereinafter referred to as “broadcast signal”) compatible with digital television broadcasting. In broadcast signals, frequency multiplexing is performed for a plurality of radio channels. Each wireless channel is formed by a plurality of segments. One segment included in one radio channel is used as one segment broadcast. That is, the program can be viewed only by receiving the segment. When an organization other than a broadcaster broadcasts an independent program by transmitting a broadcast signal, it is required to expand the broadcast area and continuously perform relaying. In order to cope with this, the following processing is executed.

  The broadcasting system according to the embodiment of the present invention is composed of a broadcasting device and a relay device. The broadcast device and the relay device are connected by a communication system such as a wireless LAN (Local Area Network) system, for example. Hereinafter, a signal defined in the communication system is referred to as a “communication signal”. The broadcasting device generates an intermediate frequency signal (hereinafter referred to as “intermediate signal”) including the independent program. Here, the intermediate signal is included in a state where the independent program is modulated. The broadcast signal is a broadcast frequency signal. Further, the intermediate signal and the broadcast signal have the same signal format except for the frequency band. That is, the intermediate signal can be said to be a signal before frequency conversion to a broadcast signal. The broadcasting device stores the intermediate signal in the communication signal and transmits the communication signal.

  The relay device receives a communication signal from the broadcast device and extracts an intermediate signal from the communication signal. The relay device converts the frequency of the intermediate signal into a broadcast signal and transmits the broadcast signal. The television broadcast receiver receives a broadcast signal from the relay device. In such a configuration, a plurality of relay devices are provided to expand the area. At that time, radio channels and segments that reduce mutual interference are used for broadcast signals transmitted from each of the plurality of relay apparatuses. Hereinafter, a combination of a radio channel and a segment is referred to as a “frequency channel”. In order to cope with this, the broadcasting apparatus defines the frequency channels to be used by each intermediate apparatus, stores a list of channels in a table, and transmits the table to each intermediate apparatus. Each intermediate device selects a frequency channel while referring to the table.

  On the other hand, the intermediate device stores the intermediate signal in the memory, extracts the intermediate signal from the memory by a FIFO (First-In First-Out), and converts the extracted intermediate signal into a broadcast signal. When the transmission path environment in the communication system deteriorates, the relay device becomes difficult to receive communication signals. For this reason, the intermediate signal stored in the memory is reduced, and the intermediate signal cannot be extracted by the FIFO. As a result, the broadcast signal is not transmitted from the relay device, and the relay is not continuously performed. The relay device according to the present embodiment monitors the data amount of a portion that is not broadcasted among the intermediate signals stored in the memory. When the amount of data decreases, the relay apparatus stops the extraction of the intermediate signal by the FIFO and switches to the extraction of the intermediate signal repeatedly.

  For digital radio broadcasting, this embodiment is applied to digital radio broadcasting by replacing one segment component with three segment components. Furthermore, this embodiment is applied to a system having the concept of segments by extracting at least one segment component and a demodulatable number of segment components. Hereinafter, descriptions of these modified examples for the sake of clarity will be omitted.

  FIG. 1 shows a configuration of a broadcasting system 100 according to an embodiment of the present invention. The broadcasting system 100 includes a first relay device 14a, a second relay device 14b, an Nth relay device 14n, and a first image receiving device 16a, which are collectively referred to as a broadcast device 10 and a relay device 14, and a second image receiving device 16. A device 16b and an M-th image receiving device 16m. The broadcast device 10 includes a broadcast device antenna 22, and the relay device 14 includes a first relay device communication antenna 24 a, a second relay device communication antenna 24 b, and an Nth relay device, which are collectively referred to as a relay device communication antenna 24. The image receiving device 16 includes a communication antenna 24n, a relay device transmitting antenna 26, a first relay device transmitting antenna 26a, a second relay device transmitting antenna 26b, and an Nth relay device transmitting antenna 26n. A first image receiving device antenna 28a, a second image receiving device antenna 28b, and an Mth image receiving device antenna 28m, which are collectively referred to as the device antenna 28, are included.

  The broadcasting device 10 generates an intermediate signal including an independent program. The intermediate signal is a signal having a different frequency while being in the same format as the broadcast signal, and the broadcast signal is a signal corresponding to digital television broadcasting. Digital television broadcasting is a system defined by, for example, ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) and DVB (Digital Video Broadcasting). In ISDB-T, frequency division multiplexing is performed on a plurality of radio channels.

  Each radio channel is formed by an OFDM (Orthogonal Frequency Division Multiplexing) signal and is formed by a plurality of segments. Specifically, 13 segments having a width of 429 KHz are included. Of the 13 segments, one is reserved for one-segment broadcasting. The segment reserved for one-segment broadcasting is a central segment and is assumed to have a segment number “0”. As described above, hereinafter, the segment and the radio channel are collectively referred to as “frequency channel”. Further, the modulation multi-level number of intermediate signals and broadcast signals is variably defined. For example, 64 QAM is used as a modulation scheme when 13 segments are used, and QPSK is used as a modulation scheme when one-segment broadcasting is used.

  Here, the broadcasting apparatus 10 generates a digital signal by performing analog / digital conversion on the intermediate signal. Also, the broadcast device 10 defines the frequency channel for each relay device 14 so that the frequency channels used by each relay device 14 do not interfere with each other, and includes it in the table. The broadcast apparatus 10 stores a table and a digital signal in a communication signal. The broadcast apparatus 10 transmits a communication signal from the broadcast apparatus antenna 22.

  For example, the relay device 14 is arranged at a position where a communication signal from the broadcasting device 10 can be received. The relay device 14 receives a communication signal from the broadcast device 10 via the relay device communication antenna 24. The relay device 14 extracts a table and a digital signal stored in the communication signal. In addition, the relay device 14 stores the extracted digital signal, that is, the independent program in the memory, and then extracts the digital signal stored in the memory using a FIFO. The relay device 14 generates an intermediate signal by performing digital / analog conversion of the digital signal into an analog signal. In addition, the relay device 14 generates a broadcast signal by frequency-converting the intermediate signal while setting the frequency of the local oscillation signal according to the frequency channel information included in the table. The relay device 14 transmits a broadcast signal via the relay device transmission antenna 26. Here, when the data amount of the unextracted portion of the digital signal stored in the memory becomes smaller than the threshold value, the relay device 14 repeatedly extracts the digital signal stored in the memory.

  The image receiving device 16 is disposed at a position where a broadcast signal from a predetermined relay device 14 can be received. The image receiving device 16 receives the broadcast signal from the relay device 14 via the image receiving device antenna 28. Here, the broadcast signal is arranged in a predetermined frequency channel. The image receiving device 16 reproduces the independent program included in the predetermined frequency channel component by demodulating the broadcast signal. The image receiving device 16 displays a program on a monitor (not shown). Here, the content of the independent program may be updated sequentially or the content may be repeated. The former corresponds to the case where the extraction is performed by the FIFO in the relay device 14, and the latter corresponds to the case where the extraction is repeatedly performed in the relay device 14. If the image receiving device 16 is arranged at a position where it can directly receive a broadcast signal from a broadcaster's broadcast station (not shown), the image receiving device 16 receives the broadcast signal and receives the program included in the broadcast signal. Can be played.

  FIG. 2 shows the configuration of the broadcasting device 10. The broadcasting device 10 includes a first generation unit 30a, a second generation unit 30b, an Nth generation unit 30n, and a first AD conversion unit 132a, a second AD conversion unit 132b, which are collectively referred to as a generation unit 30. For NAD converter 132n, first serial / IP converter 134a, second serial / IP converter 134b, Nth serial / IP converter 134n, communication unit 54, and broadcasting device, collectively referred to as serial / IP converter 134 An antenna 22, a control unit 40, a storage unit 42, and an input unit 44 are included. The generation unit 30 includes a data reception unit 32, a modulation unit 34, an IFFT unit 36, and an orthogonal modulation unit 38.

  The plurality of generation units 30 are provided so as to be associated with the plurality of relay apparatuses 14 illustrated in FIG. The data receiving unit 32 receives an independent program to be broadcast in the broadcasting system 100. The data receiving unit 32 is connected to a storage unit (not shown), and reads the independent program stored in the storage unit. Here, the independent program is moving image data and is formed as digital data. In addition, since a well-known technique should just be used for such moving image data or digital data, description is abbreviate | omitted here. In addition, the data receiving unit 32 corresponding to each generating unit 30 receives different independent programs. Note that the storage unit (not shown) may be the storage unit 42. The data reception unit 32 outputs the independent program to the modulation unit 34.

  The modulation unit 34 receives the independent program from the data reception unit 32. The modulation unit 34 modulates data corresponding to the independent program. The modulation unit 34 uses QPSK or 64QAM as a modulation method to be used for the independent modulation. Note that the modulation unit 34 selects a modulation method to be used in accordance with an instruction from the control unit 40. The modulation unit 34 sequentially outputs the modulation results to the IFFT unit 36. The IFFT unit 36 receives the modulation result from the modulation unit 34. The IFFT unit 36 generates a frequency domain OFDM signal by placing the modulation result on the frequency domain subcarriers. The IFFT unit 36 generates a time-domain OFDM signal by performing IFFT on the frequency-domain OFDM signal. Here, the OFDM signal in the frequency domain and the OFDM signal in the time domain correspond to OFDM signals determined in digital television broadcasting. The modulator 34 sequentially outputs time-domain OFDM signals to the orthogonal modulator 38.

  The quadrature modulation unit 38 generates an intermediate signal by performing quadrature modulation on the time domain OFDM signal from the modulation unit 34. As described above, the intermediate signal is a signal corresponding to the broadcast signal because the frequency band is different from that of the broadcast signal. Note that a plurality of broadcast frequencies to be used in the broadcast signal, that is, radio channels, are defined and variably defined. The AD conversion unit 132 receives the intermediate signal from the quadrature modulation unit 38 and performs analog / digital conversion on the intermediate signal to generate the above-described digital signal. For example, the AD conversion unit 132 uses an optimal quantization number corresponding to the modulation method when generating a digital signal.

  The serial / IP conversion unit 134 receives a digital signal from the AD conversion unit 132. A signal to be used for communication by a communication unit 54 described later has an IP (Internet Protocol) packet format. Since a well-known technique should just be used for an IP packet, description is abbreviate | omitted here. The serial / IP conversion unit 134 stores the digital signal in the IP packet. Hereinafter, an IP packet including a digital signal is referred to as a “communication signal”. The serial / IP conversion unit 134 outputs a communication signal to the communication unit 54.

  The communication unit 54 has a communication function corresponding to the wireless LAN system. In addition, since a well-known technique should just be used as a wireless LAN system, description is abbreviate | omitted here. The communication unit 54 performs communication with a relay device 14 (not shown) having a wireless LAN system communication function via the broadcast device antenna 22. The communication unit 54 receives a communication signal from the serial / IP conversion unit 134 and transmits the communication signal to the relay device 14 via the broadcast device antenna 22. Here, an IP address is assigned to each relay device 14, and the communication unit 54 assigns an IP address corresponding to the relay device 14 to which the communication signal is to be transmitted, to the communication signal. That is, the communication unit 54 unicasts the communication signal with the relay device 14 to which the communication signal is to be transmitted as a destination.

  The input unit 44 inputs information for identifying the relay device 14 and information regarding the bandwidth used for the broadcast signal from the relay device 14. The information for identifying the relay device 14 includes the name of the relay device 14 and the IP address of the relay device 14. The information regarding the bandwidth used for the broadcast signal from the relay device 14 includes the number of radio channels, Contains information about the number of segments. Furthermore, the input unit 44 also inputs information regarding the frequency used in the communication system with the relay device 14. The input unit 44 outputs the input information to the control unit 40.

  The control unit 40 receives information from the input unit 44. The control unit 40 determines a frequency channel to be used in the broadcast signal from each of the plurality of relay devices 14 so that the interference between the broadcast signals from each of the plurality of relay devices 14 is reduced. Here, since the frequency channel is specified by the combination of the radio channel and the segment, they are determined. More specifically, the control unit 40 selects a frequency channel that has not been used yet. Further, the control unit 40 generates an instruction regarding the frequency between the intermediate signal and the broadcast signal for each relay device 14 based on the frequency channel used in the relay device 14. Here, the frequency between the intermediate signal and the broadcast signal corresponds to the frequency of the local oscillation signal in the relay device 14.

  Further, the control unit 40 generates one table so as to include the information input at the input unit 44, the determined frequency channel, and the frequency of the local oscillation signal. Further, the table includes information related to the plurality of relay devices 14. The control unit 40 stores the generated table in the storage unit 42. The control unit 40 extracts a table from the storage unit 42 and generates a communication signal including the table. The control unit 40 outputs a communication signal to the communication unit 54. The communication unit 54 also receives a communication signal from the control unit 40 and transmits the communication signal. Here, since the communication signal including the table should be transmitted to the plurality of relay apparatuses 14, broadcast transmission or multicast transmission is performed on the communication signal.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it can be realized by a program loaded in the memory, but here it is realized by their cooperation. Draw functional blocks. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  FIG. 3 shows the configuration of the relay device 14. The relay device 14 includes a relay device communication antenna 24, a relay device transmission antenna 26, a communication unit 80, an IP / serial conversion unit 160, a storage unit 180, a signal conversion unit 162, a parameter setting unit 164, and a control unit 86. The signal conversion unit 162 includes a DA conversion unit 166, a frequency converter 116, a transmission amplification unit 118, a transmission BPF 120, and a local oscillation unit 122. As shown in FIG. 1, the broadcast system 100 includes a plurality of relay devices 14.

  Similar to the communication unit 54 (not shown), the communication unit 80 has a communication function corresponding to the wireless LAN system. The communication unit 80 performs communication with a broadcast device 10 (not shown) via the relay device communication antenna 24. The communication unit 80 receives a communication signal from the broadcast device 10 via the relay device communication antenna 24. Here, digital signals and tables are stored in the communication signal. The communication unit 80 demodulates the received communication signal and then outputs it to the IP / serial conversion unit 160.

  The IP / serial converter 160 performs the reverse operation of the serial / IP converter 134 (not shown). The IP / serial conversion unit 160 receives the demodulated communication signal from the communication unit 80. Here, the communication signal corresponds to an IP packet including a table and a digital signal. The IP / serial converter 160 extracts a table or a digital signal from the communication signal. The IP / serial conversion unit 160 outputs the extracted digital signal (hereinafter also referred to as “digital signal”) to the storage unit 180, and outputs the extracted table to the parameter setting unit 164.

  The storage unit 180 corresponds to the above-described memory, receives a digital signal from the IP / serial conversion unit 160, and stores the digital signal. That is, the storage unit 180 stores the independent program stored in the communication signal received by the communication unit 80. In addition, the storage unit 180 outputs the stored digital signal to the DA conversion unit 166. Here, the address control at the time of writing the digital signal to the storage unit 180 and the address control at the time of reading the digital signal from the storage unit 180 are performed by the control unit 86.

  In a normal state, the control unit 86 outputs the digital signal stored in the storage unit 180 using a FIFO. In other words, the digital signal stored in the storage unit 180 is preferentially read out from the previously written digital signal. Note that the digital signal to be read is a digital signal that has not been read at that time. Therefore, the control unit 86 reads the digital signal from the storage unit 180 in accordance with the order of progression of the independent program so that the digital signal once read is not read again.

  On the other hand, the control unit 86 monitors the data amount of the unextracted portion of the digital signal stored in the storage unit 180. For example, when successive digital signals are written at successive addresses, the control unit 86 grasps the data amount of the unextracted portion by calculating the difference between the write address and the read address. When the data amount becomes smaller than the threshold value, the control unit 86 stops the output by the FIFO and repeatedly reads out the digital signal in a predetermined period. That is, the control unit 86 performs control so that the independent program for a predetermined period is repeatedly broadcast.

  Here, the digital signal at the time of repeated reading may be a digital signal received from the IP / serial conversion unit 160, but another digital signal is stored in the storage unit 180 in advance separately from the digital signal. May be. That is, an independent program for repeated broadcasting may be stored in advance. At that time, an independent program having contents completed in a predetermined period is prepared. The DA conversion unit 166 receives a digital signal from the IP / serial conversion unit 160. The DA conversion unit 166 generates an intermediate signal by performing digital / analog conversion on the digital signal based on a preset quantization number. The DA converter 166 outputs the intermediate signal to the frequency converter 116.

  The parameter setting unit 164 receives a table from the IP / serial conversion unit 160. The parameter setting unit 164 extracts information on the frequency of the local oscillation signal from the table, and sets the frequency of the local oscillator for the local oscillation unit 122 based on the information on the frequency of the local oscillation signal. The local oscillator 122 outputs a local oscillation signal having a frequency corresponding to the setting by the parameter setting unit 164 to the frequency converter 116. The frequency converter 116 receives a local oscillation signal from the local oscillation unit 122 and also receives an intermediate signal from the DA conversion unit 166. The frequency converter 116 generates a broadcast signal by frequency-converting the intermediate signal from the intermediate frequency band to the broadcast frequency band. The frequency converter 116 outputs the broadcast signal to the transmission amplifier 118.

  The transmission amplifier 118 amplifies the broadcast signal from the frequency converter 116 and outputs it to the transmission BPF 120. The transmission BPF 120 attenuates an image signal included outside the broadcast frequency band of the received broadcast signal, and transmits the broadcast signal as an electromagnetic wave from the relay device transmission antenna 26. The transmission BPF 120 sets a pass band in accordance with an instruction from the parameter setting unit 164. Here, the transmission BPF 120 may not be a tunable filter as described above. At that time, a double conversion configuration in which two local oscillation units 122 are provided, and an LPF is also provided.

  The operation of the broadcasting system 100 having the above configuration will be described. FIG. 4 is a flowchart illustrating a procedure of relay processing in the relay device 14. The control unit 86 checks the amount of untransmitted data in the storage unit 180 (S10). If the data amount is not smaller than the threshold value (N in S12), the control unit 86 performs transmission by FIFO (S14). On the other hand, if the data amount is smaller than the threshold value (Y in S12), the control unit 86 executes transmission by repetition (S16).

  Next, a modified example will be described. The present invention relates to a relay device that receives a broadcast signal transmitted from a broadcaster's broadcast station, amplifies the received signal, and transmits the amplified signal. In order to deal with the same problem as that in the embodiment, the relay device according to the modification executes the following process. The relay device includes two relay devices, that is, a front-stage relay device and a rear-stage relay device. The upstream relay device and the downstream relay device are connected by a communication system such as a wireless LAN system, similarly to the broadcast device and the relay device in the embodiment. The upstream relay device receives the broadcast signal, converts the frequency of the broadcast signal into an intermediate signal, stores the intermediate signal in the communication signal, and transmits the communication signal. Here, the intermediate signal includes at least one radio channel included in the broadcast signal. In addition, at least one segment may be included. The rear-stage relay device executes the same processing as the relay device in the embodiment.

  FIG. 5 shows a configuration of a broadcast system 500 according to a modification of the present invention. The broadcasting system 500 includes a broadcasting station 510, a front-stage relay device 512, a rear-stage relay device 514, and an image receiving device 516. The broadcasting station 510 includes a broadcasting station antenna 518, the upstream relay device 512 includes a upstream relay device receiving antenna 520 and a upstream relay device communication antenna 522, and the downstream relay device 514 includes a downstream relay device communication antenna 524. The rear-stage relay apparatus transmitting antenna 526 is included, and the image receiving apparatus 516 includes the image receiving apparatus antenna 528. Here, the upstream relay device 512, the downstream relay device 514, and the image receiving device 516 are installed in the building 502.

  The broadcast station 510 transmits a broadcast signal from the broadcast station antenna 518. The upstream relay device 512 is installed near the outside of the building 502, for example, at a position where a broadcast signal from the broadcast station 510 can be received. The upstream relay device 512 receives a broadcast signal from the broadcast station 510 via the upstream relay device receiving antenna 520. The upstream relay apparatus 512 extracts at least one radio channel component of the broadcast signal or at least one segment component in the radio channel, and generates an intermediate signal by frequency-converting it.

  In the following, it is assumed that the number of radio channel components and the number of segment components included in the intermediate signal may be arbitrary values. Further, the upstream relay device 512 generates a digital signal by performing analog / digital conversion on the intermediate signal. The upstream relay device 512 is also compatible with a communication system such as a wireless LAN system, and stores a digital signal in the communication signal. The upstream relay device 512 transmits a communication signal from the upstream relay device communication antenna 522 to the downstream relay device 514. Further, the upstream relay apparatus 512 stores the above-described table in the communication signal and transmits the communication signal. The rear-stage relay device 514 corresponds to the relay device 14 in FIG. 1, and the image receiving device 516 corresponds to the image receiving device 16 in FIG.

  FIG. 6 shows a configuration of the upstream relay device 512. The upstream relay device 512 includes a upstream relay device receiving antenna 520, a upstream relay device communication antenna 522, a signal conversion unit 530, a serial / IP conversion unit 534, a parameter setting unit 536, a communication unit 554, and a control unit 558. The signal conversion unit 530 includes a reception BPF 560, a reception amplification unit 562, a frequency converter 564, an oscillation unit 572, and an AD conversion unit 532.

  The upstream relay device receiving antenna 520 receives a broadcast signal from a broadcast station 510 (not shown). The upstream relay device receiving antenna 520 outputs the received broadcast signal to the receiving BPF 560. The reception BPF 560 extracts a passband portion from the broadcast signal from the upstream relay device reception antenna 520. Here, the passband is set in advance to a value that allows extraction of a plurality of radio channel components and one radio channel component (hereinafter collectively referred to as “channel components”). Since a known technique may be used for the reception BPF 560, description thereof is omitted here. One channel component includes a plurality of segment components, and the reception BPF 560 may extract at least one segment component. Here, for clarity of explanation, the extracted segment component may also be referred to as a “channel component”. Reception BPF 560 outputs the channel component to reception amplification section 562.

  The reception amplification unit 562 amplifies the channel component from the reception BPF 560. Here, the channel component is a signal in the broadcast frequency band. Reception amplification section 562 outputs the amplified channel component to frequency converter 564. The frequency converter 564 receives the channel component from the reception amplification unit 562 and receives the local oscillation signal from the oscillation unit 572. Note that the oscillation unit 572 sets the frequency of the local oscillation signal in accordance with an instruction from the parameter setting unit 536. Here, the frequency of the local oscillation signal is set in accordance with the passband frequency set in reception BPF 560.

  In addition, in order to simplify the description, it is assumed that the parameter setting unit 536 stores frequency settings in advance according to the channel arrangement in the broadcast signal. When switching the frequency setting, the parameter setting unit 536 may receive a switching instruction via a predetermined interface. The frequency converter 564 frequency-converts the broadcast frequency band channel component from the reception amplification unit 562 to the intermediate frequency band channel component by the local oscillation signal from the oscillation unit 572. Here, the channel component in the intermediate frequency band corresponds to the above-described intermediate signal. The frequency converter 564 outputs the intermediate signal to the AD conversion unit 532.

  The AD conversion unit 532 receives the intermediate signal from the frequency converter 564 and performs analog / digital conversion on the intermediate signal to generate the above-described digital signal. Here, the AD conversion unit 532 receives an instruction relating to the quantization number from the parameter setting unit 536 when generating a digital signal. Here, in order to simplify the description, it is assumed that the quantization number is fixed. The serial / IP conversion unit 534 corresponds to the serial / IP conversion unit 134 in FIG. 2, and the communication unit 554 corresponds to the communication unit 54 in FIG. 2, so description thereof is omitted here. Note that the communication unit 554 also transmits a communication signal in which the above-described table is stored.

  Next, another modification will be described. In the above description, the relay device 14 and the subsequent relay device 514 transmit the digital signal read by the FIFO to the normal state, and the digital signal read repeatedly when the amount of untransmitted data decreases. Is sending. On the other hand, when the relay apparatus according to another modification operates in the normal state in the same manner as before and cannot receive a communication signal, the broadcast signal is notified to that effect (hereinafter referred to as “wireless LAN failure information”). Broadcast. As a result, when the wireless LAN failure information is received in the image receiving device 16 or the image receiving device 516, the user can recognize that a failure has occurred. On the other hand, when the wireless LAN failure information is not received in the image receiving device 16 or the image receiving device 516, but the broadcast signal is not received, the user is in trouble with the relay device 14 or the subsequent relay device 514. Can be recognized. The user can easily identify the cause of the failure.

  A broadcast system according to another modification is the same type as the broadcast system 100 of FIG. 1 and the broadcast system 500 of FIG. When the communication system according to another modification is the same type as that of the broadcasting system 100, the broadcasting device 10 is the same type as that in FIG. 2, and the relay device 14 is the same type as that in FIG. When the communication system according to another modification is the same type as that of the broadcasting system 500, the upstream relay device 512 is the same type as that in FIG. 6, and the downstream relay device 514 is the same type as that in FIG. is there. Here, the difference will be mainly described. Further, the relay device 14 will be described regardless of whether it is the relay device 14 or the subsequent relay device 514.

  As described above, the storage unit 180 stores the digital signal from the IP / serial conversion unit 160. The control unit 86 monitors the data amount of the unextracted portion of the digital signal stored in the storage unit 180. If the data amount is not smaller than the threshold value, the control unit 86 outputs a digital signal by FIFO as described above. On the other hand, when the data amount becomes smaller than the threshold value, the control unit 86 stores in the digital signal that the communication signal reception status in the communication unit 80 has deteriorated, and outputs the digital signal. Note that the control unit 86 may measure the throughput of the communication signal received by the communication unit 80 instead of monitoring the amount of data in the control unit 86. Here, a known technique may be used for the measurement of the throughput. When the throughput becomes smaller than the threshold value, the control unit 86 may store in the digital signal that the communication signal reception status in the communication unit 80 is deteriorated, and output the digital signal.

  Next, still another modification will be described. In the description so far, the digital signal read by the FIFO is transmitted in a normal state, and the digital signal read repeatedly is transmitted when the amount of untransmitted data decreases. A relay apparatus according to another modification operates in the same manner as before, but a TS (Transport Stream) signal is included in the communication signal as it is.

  FIG. 7 shows a configuration of a broadcasting system 600 according to still another modified example of the present invention. The broadcast system 600 includes a broadcast device 602 and a relay device 604. The broadcast device 602 includes a first storage unit 610, a communication unit 612, and a broadcast device communication antenna 614. The relay device 604 includes a relay device communication antenna 646, a communication unit 648, a generation unit 620, a signal conversion unit 622, a relay device broadcast antenna 624, and a control unit 626. Further, the generation unit 620 includes a data reception unit 628, a second storage unit 630, a modulation unit 632, an IFFT unit 634, and an orthogonal modulation unit 636. The signal conversion unit 622 includes a frequency conversion unit 638, a local oscillation unit 640, and a transmission. An amplification unit 642 and a transmission BPF 644 are included.

  The first storage unit 610 stores the independent program as digital data. Further, the independent program stored in the first storage unit 610 has a TS signal format. Since the TS signal is a known technique, description thereof is omitted here. The communication unit 612 and the broadcasting device communication antenna 614 correspond to the communication unit 54 and the broadcasting device antenna 22 of FIG. 2, generate a communication signal in which the TS signal stored in the first storage unit 610 is stored, and perform communication. Send a signal.

  The relay device communication antenna 646 and the communication unit 648 correspond to the relay device communication antenna 24 and the communication unit 80 in FIG. 3 and receive communication signals. In addition, the communication unit 648 extracts a TS signal from the communication signal. The data receiving unit 628 corresponds to the data receiving unit 32 in FIG. 2 and receives a TS signal from the communication unit 648. The second storage unit 630 corresponds to the storage unit 180 of FIG. 3, receives the TS signal from the data reception unit 32, and stores the TS signal. The control unit 626 writes the TS signal to the storage unit 180 and reads the TS signal from the storage unit 180. Since the control unit 626 operates in the same manner as the control unit 86 in FIG. 3, the description thereof is omitted here.

  The modulation unit 632, the IFFT unit 634, and the quadrature modulation unit 636 correspond to the modulation unit 34, the IFFT unit 36, and the quadrature modulation unit 38 of FIG. Also, the frequency converter 638, local oscillator 640, transmission amplifier 642, transmission BPF 644, and relay device broadcast antenna 624 are the frequency converter 116, local oscillator 122, transmission amplifier 118, transmission BPF 120 in FIG. This corresponds to the relay device transmitting antenna 26. As a result, the relay device broadcast antenna 624 transmits a broadcast signal.

  According to the embodiment of the present invention, since the wireless LAN system is used between the broadcast device and the relay device, the transmission power from the relay device can be reduced. Further, since the transmission power from the relay device is reduced, the occurrence of interference can be suppressed. In addition, since the occurrence of interference is suppressed, the degree of freedom of installation of the relay device can be increased. Further, since a wireless LAN system is used between the broadcasting device and the relay device, the area can be expanded. Moreover, since a wireless LAN system is used between the broadcasting device and the relay device, the area can be expanded while increasing the degree of freedom of installation of the relay device.

  In addition, when the data amount of the untransmitted portion decreases, a broadcast signal in which the independent program is repeated is transmitted, so that continuous relay can be executed. Moreover, since the independent program for repeatedly storing in the broadcast signal is stored separately, the length of the independent program can be freely designed. In addition, since the length of the independent program is freely designed, the length of the independent program can be adjusted to the repetition period. In addition, since the length of the independent program is adjusted to the repetition period, it is possible to provide an independent program that reduces the user's uncomfortable feeling.

  Further, since the modulation function regarding the broadcast signal is omitted in the relay device, the processing of the relay device can be simplified. Further, since the table is transmitted from the broadcasting device to the relay device and the relay device operates according to the table, the processing in the relay device can be simplified. Moreover, since the processing of the relay device is simplified, the cost can be reduced. Moreover, since the broadcasting apparatus determines a channel in consideration of interference between relay apparatuses, the interference can be reduced. In addition, since the interference is reduced, the broadcast quality can be improved. Further, since the relay device sets the frequency of the local oscillation signal according to the table, the processing can be simplified. In addition, since information regarding a plurality of relay devices is included in the table, the plurality of relay devices can be controlled. In addition, when the reception state of the communication signal deteriorates, the fact is broadcast so that the cause of the failure can be easily notified.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In the embodiment of the present invention, the communication system between the broadcasting device 10 and the relay device 14 and the communication system between the upstream relay device 512 and the downstream relay device 514 are wireless LAN systems. However, the present invention is not limited to this. For example, the communication system may be a wired LAN system. According to this modification, the transmission quality of the communication system can be improved. Further, when the transmission speed of the wired LAN system is high, the number of relay devices 14 and rear-stage relay devices 514 accommodated in the broadcast system 100 or the broadcast system 500 can be increased.

  In the embodiment of the present invention, the broadcasting device 10 and the upstream relay device 512 generate a table so as to collect information related to the plurality of relay devices 14 and the plurality of downstream relay devices 514, and notify the table. However, the present invention is not limited to this. For example, the broadcasting device 10 may create a table for each relay device 14 and transmit the table to only the relay device 14 corresponding to the table. At that time, the destination of the table is the IP address of the relay device 14 corresponding to the table. Further, the same processing may be performed in the upstream relay device 512. According to this modification, the relay device 14 and the subsequent relay device 514 do not have to extract information corresponding to themselves from the table, and thus the processing amount of the relay device 14 and the subsequent relay device 514 can be reduced.

  In the embodiment of the present invention, the plurality of generation units 30 in the broadcasting device 10 are provided so as to be associated with the plurality of relay devices 14, that is, in a one-to-one correspondence. However, the present invention is not limited to this. For example, one generation unit 30 may be provided for a plurality of relay devices 14. At that time, the broadcast device 10 multicasts a communication signal to the plurality of relay devices 14. According to this modification, when the same program is transmitted from the plurality of relay apparatuses 14, the traffic of the communication signal can be reduced.

  In the embodiment of the present invention, a communication signal storing an intermediate signal is transmitted from the broadcast apparatus 10 to the relay apparatus 14. However, the present invention is not limited to this, and for example, the relay device 14, the baseband time domain OFDM signal, and the baseband frequency domain OFDM signal may be transmitted from the broadcast device 10. In the following, these signals are collectively referred to as baseband signals. At that time, the relay device 14 performs conversion to a broadcast signal after performing orthogonal modulation on the baseband signal. The same processing may be performed between the upstream relay device 512 and the downstream relay device 514. At that time, the upstream relay device 512 performs quadrature detection and demodulation on the intermediate signal. According to this modification, the freedom degree of the structure of the broadcast system 100 or the broadcast system 500 can be improved.

It is a figure which shows the structure of the broadcast system which concerns on the Example of this invention. It is a figure which shows the structure of the broadcasting apparatus of FIG. It is a figure which shows the structure of the relay apparatus of FIG. It is a flowchart which shows the procedure of the relay process in the relay apparatus of FIG. It is a figure which shows the structure of the broadcast system which concerns on the modification of this invention. It is a figure which shows the structure of the upstream relay apparatus of FIG. It is a figure which shows the structure of the broadcast system which concerns on another modification of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Broadcasting device, 14 Relay device, 16 Image receiving device, 22 Broadcast device antenna, 24 Relay device communication antenna, 26 Relay device transmitting antenna, 28 Image receiving device antenna, 30 Generating unit, 32 Data receiving unit, 34 Modulating unit , 36 IFFT unit, 38 orthogonal modulation unit, 40 control unit, 42 storage unit, 44 input unit, 54,80 communication unit, 86 control unit, 100 broadcasting system, 116 frequency converter, 118 transmission amplification unit, 120 BPF for transmission 122 local oscillation unit, 132 AD conversion unit, 134 serial / IP conversion unit, 160 IP / serial conversion unit, 162 signal conversion unit, 164 parameter setting unit, 166 DA conversion unit, 180 storage unit.

Claims (4)

A receiving unit for receiving a communication signal storing content data;
A storage unit for storing content data stored in the communication signal received by the reception unit;
The content data stored in the storage unit is stored in a first-in first-out broadcast signal, and a broadcast unit that broadcasts the broadcast signal,
The broadcast unit repeats the content data stored in the storage unit when the data amount of the portion not stored in the broadcast signal among the content data stored in the storage unit becomes smaller than a threshold value. A relay device that stores the broadcast signal and broadcasts the broadcast signal.   The storage unit stores in advance content data to be repeatedly stored in the broadcast signal in the broadcast unit, separately from the content data stored in the communication signal received by the reception unit. Item 4. The relay device according to Item 1. A receiving unit for receiving a communication signal storing content data;
A storage unit for storing content data stored in the communication signal received by the reception unit;
The content data stored in the storage unit is stored in a first-in first-out broadcast signal, and a broadcast unit that broadcasts the broadcast signal,
When the reception state of the communication signal in the receiving unit deteriorates, the broadcast unit stores the fact in the broadcast signal and broadcasts the broadcast signal. A communication device for transmitting a communication signal storing content data;
After receiving the communication signal from the communication device and storing the content data stored in the received communication signal in the memory, the content data stored in the memory is stored in the broadcast signal on a first-in first-out basis, and the broadcast signal is broadcast. And a relay device that
In the content data stored in the memory, when the amount of data not stored in the broadcast signal is smaller than the threshold, the relay device repeatedly stores the content data stored in the memory in the broadcast signal, A broadcasting system characterized by broadcasting a broadcast signal.

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