JP4551352B2 - Relay device - Google Patents

Description

  The present invention relates to a transmission technique and a reception technique, and more particularly to a transmission apparatus and a reception apparatus that transmit a signal in which other information is added to desired information.

  In a broadcasting system such as a television broadcasting system, a signal is transmitted as an electromagnetic wave from a broadcasting station. The receiver receives a signal transmitted from a broadcast station or a signal relayed by a relay station, and acquires image information, audio information, and the like from the received signal. In an analog television broadcasting system, when an abnormal state occurs in a transmission facility at a broadcast station or a relay facility at a relay station, the transmission facility or the relay facility outputs alarm information. The alarm information includes information related to a failure in the transmission facility, a failure in the relay facility, and an abnormality in the incidental facility. The incidental facility abnormality is, for example, a power failure, and monitoring the power failure means that broadcasting stops after a certain period of time even if there is no failure of the device. By knowing the occurrence of such a power outage, the necessity of refueling the generator is determined.

Therefore, an abnormal state in an analog television broadcasting system is generally detected by monitoring alarm information. For example, monitoring is performed by notifying the broadcast station of alarm information through another communication line such as a telephone line. Monitoring is also performed by a consignment monitoring system. In the consignment monitoring system, alarm information is superimposed on a signal transmitted from a broadcast station or a relay station, and the consignment monitor such as an electric store receives the information through an antenna similar to that of a general viewer. At that time, the consignment supervisor confirms the alarm information superimposed on the received signal with an LED or the like (for example, see Patent Document 1).
JP-A-2005-244918

  The consignment monitoring system has the advantage that the maintenance can be reduced compared to providing another communication line for transmitting alarm information because the broadcast wave itself becomes a transmission line. Is widely adopted. When the analog television broadcasting system adopts the NTSC (National Television Standards Committee) system, alarm information is superimposed as an amplitude variation on an FM (Frequency Modulation) signal to which an audio signal is to be transmitted. In the digital television broadcasting system, similarly to the analog television broadcasting system, a signal transmitted from a broadcasting station or a relay station is received by a receiver. Also, alarm information is output from the transmission facility or relay device.

  Therefore, it is preferable that the digital television broadcasting system is monitored by the consignment monitoring system as in the case of the analog television broadcasting system. However, when the digital television broadcasting system adopts the ISDB-T (Terrestrial Integrated Services Digital Broadcasting) method, a plurality of subcarriers are arranged over the transmission band, and 64QAM (Quadrature Amplitude Modulation) for each subcarrier. Etc. are modulated. For this reason, it is difficult to superimpose alarm information in a digital television broadcast system, as in an analog television broadcast system.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a relay device that superimposes information other than image information in a digital television broadcasting system.

  In order to solve the above-described problem, a transmitting apparatus according to an aspect of the present invention is configured to input a main signal including at least information obtained by performing interleaving, and a predetermined signal with respect to a main signal input in the input unit. A transmission unit that performs transmission while using a carrier frequency and a predetermined antenna. The input unit also inputs a sub-signal including additional information, and the transmission unit uses the same carrier frequency as the main signal and the same antenna as the main signal while transmitting the main signal. Also, the sub-signal input at the input unit is transmitted in a period shorter than the period as a unit of interleaving.

  According to this aspect, even in the period in which the main signal is transmitted, the sub-signal is transmitted in a period shorter than the period that is the unit of interleaving. Therefore, the same carrier frequency as the main signal and the same antenna as the main signal are transmitted. While using it, a sub-signal as alarm information can be transmitted.

  The transmission unit may transmit the sub signal even in the period in which the main signal is transmitted by deleting the main signal portion corresponding to the period in which the sub signal is to be transmitted from the main signal. In this case, since the main signal is deleted, only the sub signal can be transmitted in the deleted period.

  The transmission unit may transmit the sub signal even in the period in which the main signal is transmitted by superimposing the sub signal on the main signal over the period in which the sub signal is to be transmitted. In this case, since the sub signal is superimposed on the main signal, the sub signal can be transmitted without stopping the transmission of the main signal.

  You may further provide the receiving part which receives the signal from another transmission apparatus and outputs the received signal as a main signal to an input part. The signal received by the receiving unit includes a main signal including information on at least interleaving, and a sub-signal transmitted in a period shorter than a period that is a unit of interleaving in the period in which the main signal is transmitted. The transmission unit may transmit the sub-signal input in the input unit during a period other than the period that is a unit of interleaving including the sub-signal from another transmission apparatus. In this case, it is possible to reduce the possibility that a plurality of sub-signals are transmitted in a single interleaving unit, so that it is possible to suppress deterioration in the transmission characteristics of the main signal.

  Another aspect of the present invention is a receiving device. This apparatus receives a main signal that is transmitted using a predetermined carrier frequency and a predetermined antenna and that includes a main signal including information on at least interleaving, and the reception unit receives the main signal. And a processing unit for extracting information included in the main signal. The receiving unit is a sub-signal transmitted using the same carrier frequency as the main signal and the same antenna as the main signal, and in the period in which the main signal is transmitted, the interleaving unit period The sub-signal transmitted in a short period is received, and the processing unit extracts information included in the sub-signal received by the receiving unit.

  According to this aspect, even in the period in which the main signal is transmitted, the sub-signal is transmitted in a period shorter than the period that is the unit of interleaving. Therefore, the same carrier frequency as the main signal and the same antenna as the main signal are transmitted. The sub signal as the alarm information can be received while using.

  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, information other than image information can be superimposed also in a digital television broadcasting system.

  Before describing the present invention in detail, an outline will be described. The embodiment of the present invention is constituted by a transmitting device that transmits a signal (hereinafter referred to as “digital broadcasting wave”) corresponding to digital television broadcasting, a relay device that relays the digital broadcasting wave, and a receiving device that receives the digital broadcasting wave. The present invention relates to a digital television broadcasting system. The digital broadcast wave is composed of a plurality of subcarriers, and each subcarrier is modulated by 64QAM or the like. In order to superimpose alarm information on such a digital broadcast wave, the digital television broadcast system according to the present embodiment executes the following processing.

  Although details will be described later, a transmission apparatus in a digital television broadcasting system performs mapping to 64QAM or the like after performing error correction coding on information to be transmitted. Furthermore, the transmission apparatus performs frequency interleaving and time interleaving on the mapped signal, and generates a digital broadcast wave by executing IFFT (Inverse Fast Fourier Transform) on the result. Frequency interleaving and time interleaving are executed for the purpose of improving required C / N and fading tolerance, and improve error correction capability.

  Since such interleaving is performed, the code error rate can be reduced even for burst errors such as instantaneous interruption of radio waves that occur during switching of redundant systems of devices, and errors due to fading and interference. Improved. As a result, the viewer's screen is not disturbed even if an instantaneous interruption of radio waves occurs. Therefore, even if the digital broadcast wave is stopped in a period shorter than the period that is a unit of time interleaving, viewing is not affected. Therefore, when receiving the alarm information through internal processing, the transmission device and the relay device superimpose the alarm information in a period shorter than a period that is a unit of time interleaving in the digital broadcast wave.

  Fig.1 (a) shows the structure of the transmitter 100 which concerns on the Example of this invention. The transmission device 100 includes a first insertion unit 12a, a second insertion unit 12b, which are collectively referred to as a generation unit 10, an insertion unit 12, and a first transmission unit 14a, a second transmission unit 14b, and a switching unit 16, which are collectively referred to as a transmission unit 14. A transmission antenna 18 and a monitoring control unit 20.

  The generation unit 10 receives information to be transmitted and generates a signal including such information (hereinafter referred to as “main signal”). Information to be transmitted includes video information and audio information. The generation unit 10 performs error correction coding, interleaving, and modulation to generate a main signal. The generation unit 10 outputs an intermediate frequency signal. FIG. 2 shows the configuration of the generation unit 10. The generation unit 10 includes an encoding unit 30, an interleaving unit 32, a mapping unit 34, an IFFT unit 36, and an orthogonal modulation unit 38. Here, of the actual ISDB-T, the portions necessary for the description of the present embodiment are shown, but in addition to these configurations, outer encoding by Reed-Solomon code, bit interleaving, byte interleaving, etc. are included. May be.

  The encoding unit 30 performs error correction encoding on information to be transmitted. The encoding unit 30 performs convolutional encoding as error correction encoding. The mapping unit 34 maps the signal that has been subjected to error correction coding to a constellation corresponding to a predetermined modulation method. Here, 64QAM is used as the predetermined modulation method, but 16QAM, QPSK (Quadrature Phase Shift Keying), or the like may be used. The interleaving unit 32 performs frequency interleaving after performing time interleaving on the mapped signal. Time interleaving is performed in order to reduce the influence of a burst error or the like during transmission, and distributes the mapped signal in the time axis direction. The dispersion in the time axis direction is executed with a predetermined period as one unit, and the period is defined as a period as a unit of time interleaving. In addition, a period as a unit of time interleaving and a pattern of time interleaving are defined in advance. Frequency interleaving is configured by combining interleaving between segments and interleaving within segments.

  The IFFT unit 36 performs conversion from a frequency domain signal to a time domain signal by performing IFFT on the interleaved signal. Here, the number of subcarriers is defined to be “1249” in mode 1, “2497” in mode 2, and “5617” in mode 3. The quadrature modulation unit 38 performs quadrature modulation on the time domain signal and outputs an intermediate frequency signal. In the configuration of the encoding unit 30 as described above, various parameters are set as follows, for example. When the guard interval length is 1/8 in mode 3, the effective symbol length is 1.008 ms, the guard interval length is 0.126 ms, the number of symbols / frame is 204, and the frame length is 231.336 ms. The time interleaving length is 2 units or 1 unit, the time interleaving unit length is 96 symbols, and the time interleaving time is 217.728 ms or 108.864 ms. Here, there is no direct connection between the time interleave length and the frame length. Returning to FIG.

  The monitoring control unit 20 generates the alarm information described above. The monitoring control unit 20 monitors the failure of the transmission device 100, generates alarm information when a failure occurs, or generates alarm information when a power failure is detected. Since such alarm information is an additional signal with respect to the main signal, the alarm information is hereinafter also referred to as a sub signal. Here, a known technique may be used for generating the alarm information, and thus the description thereof is omitted.

  The first insertion unit 12a and the first transmission unit 14a constitute one transmission system (hereinafter referred to as “first transmission system”), and the second insertion unit 12b and the second transmission unit 14b are separate transmission systems ( Hereinafter, it is referred to as a “second transmission system”. One of the first transmission system and the second transmission system is performing transmission, and the rest is a redundant system. These selections are made by the monitoring control unit 20. Since the first transmission system and the second transmission system are configured in the same manner, they will be collectively referred to as the insertion unit 12 and the transmission unit 14 here.

  The insertion unit 12 receives the main signal from the generation unit 10. As described above, the main signal includes information on at least interleaving. The insertion unit 12 outputs the input main signal to the transmission unit 14 when the sub-signal is not input from the monitoring control unit 20. On the other hand, when the insertion unit 12 inputs a sub signal from the monitoring control unit 20, that is, when the monitoring control unit 20 outputs alarm information, the sub signal is superimposed on the main signal over a period in which the sub signal should be transmitted. The superposition of the sub signal is realized by attenuating the amplitude of the main signal. Therefore, the insertion part 12 is comprised by switch elements, such as a diode, and a variable attenuator. Since the main signal is subjected to IFFT, the amplitude component fluctuates, but the sub signal is superimposed so that the amplitude is smaller than the fluctuating amplitude.

  By such processing, the insertion unit 12 transmits the sub-signal input at the input unit in a period shorter than the period that is a unit of interleaving even during the period in which the main signal is transmitted. For example, as described above, when the period serving as the unit of interleaving is 217.728 ms or 108.864 ms, the insertion unit 12 superimposes the sub-signal on the main signal over a period of about 10 ms. Note that the period in which the sub signal is superimposed on the main signal may be set so that the deterioration of the reception characteristic is reduced, and may be specified by simulation or experiment.

  FIGS. 3A and 3B show an overview of time interleaving performed on a signal processed in transmitting apparatus 100 and the timing of a sub-signal inserted in insertion unit 12. FIG. 3A shows a series of signals input to the interleaving unit 32 of FIG. 2, that is, a main signal. The signal sequence is formed by a plurality of symbols, and one time interleave period is formed by N symbols. Here, each of the N symbols is denoted as a first symbol to an Nth symbol. The time interleaving period is defined to be repeated, and is arranged as the (i−1) -th time interleaving period, the i-th time interleaving period, and the (i + 1) -th time interleaving period.

  One symbol may be a collection of signals as a unit of IFFT, may be a collection of signals mapped to one, or may be bits or bytes. The interleaving unit 32 changes the order of the N symbols included in the time interleaving period within one time interleaving period. FIG. 3B shows a sub signal inserted in the insertion unit 12. The sub signal is not inserted during the Low period, and the sub signal is inserted during the High period. As shown in the figure, the period in which the sub signal is inserted is shorter than one time interleaving period. As described above, the insertion unit 12 attenuates the amplitude of the main signal during a period in which such a sub signal is inserted. Returning to FIG.

  The transmission unit 14 converts the frequency of the signal from the insertion unit 12 from an intermediate frequency to a radio frequency. Here, one operation of the first transmission unit 14 a or the second transmission unit 14 b is instructed by the monitoring control unit 20. Moreover, the transmission part 14 amplifies the signal converted into the radio frequency. The switching unit 16 selects one of the signals from the first transmission unit 14 a or the second transmission unit 14 b according to the instruction from the monitoring control unit 20, and the transmission antenna 18 receives the signal from the switching unit 16. Send. Through the above processing, the transmission unit 14 transmits the main signal from the insertion unit 12 while using the radio frequency as the predetermined carrier frequency and the transmission antenna 18 as the predetermined antenna. In addition, the transmission unit 14 uses the same carrier frequency and the same antenna as the main signal and transmits the main signal in a period shorter than the period of the interleaving unit even in the period of transmitting the main signal. Send a signal.

  In the above configuration, the transmission unit 14 is arranged at the subsequent stage of the insertion unit 12. The insertion unit 12 receives the main signal of the intermediate frequency from the generation unit 10, inserts the sub signal into the main signal of the intermediate frequency, and the transmission unit 14 converts the main signal with the sub signal inserted into a radio frequency. . However, the insertion unit 12 may be disposed after the transmission unit 14. In this case, the insertion unit 12 receives a radio frequency main signal from the transmission unit 14 and inserts a sub-signal into the radio frequency main signal. Further, the insertion unit 12 may be disposed between the IFFT unit 36 and the orthogonal modulation unit 38 in the generation unit 10. In this case, the insertion unit 12 receives a baseband main signal and inserts a sub-signal into the baseband main signal, and the quadrature modulation unit 38 converts the main signal into which the sub-signal is inserted into an intermediate frequency.

  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 is realized by a program having a communication function loaded in the memory. Describes functional blocks realized by collaboration. 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.1 (b) shows the structure of the relay apparatus 110 based on the Example of this invention. In FIG.1 (b), the component which attached | subjected the code | symbol same as the code | symbol in Fig.1 (a) has the same function as the corresponding component of Fig.1 (a). The relay device 110 includes, in addition to the transmission device 100, a reception antenna 22 and a first reception unit 24a and a second reception unit 24b collectively referred to as a reception unit 24.

  The reception antenna 22 receives a radio frequency signal from the transmission apparatus 100 or another relay apparatus 110 (not shown). Here, the received radio frequency signal is a signal equivalent to the signal transmitted from the transmitting antenna 18. The receiving unit 24 converts the frequency of the signal received by the receiving antenna 22 from a radio frequency to an intermediate frequency. The receiving unit 24 outputs the signal converted to the intermediate frequency to the inserting unit 12 as the main signal described above. Since the process after the insertion part 12 is the same as the process in Fig.1 (a), description is abbreviate | omitted. Here, FIGS. 3A to 3B also show an overview of the time interleaving performed on the signal processed in the relay apparatus 110 and the timing of the sub signal inserted in the insertion unit 12.

  FIG. 4 shows a configuration of the receiving apparatus 120 according to the embodiment of the present invention. The receiving device 120 includes a receiving antenna 50, a receiving unit 52, a main signal processing unit 54, a program processing unit 56, an output unit 58, a determination unit 60, a sub signal processing unit 62, a warning unit 64, and a control unit 66. The main signal processing unit 54 includes an orthogonal detection unit 76, an FFT unit 68, a deinterleaving unit 72, a demapping unit 70, and a decoding unit 74.

  The receiving unit 52 receives signals from the transmission device 100 and the relay device 110 (not shown) via the reception antenna 50. Here, as described above, the received signal includes a main signal that is transmitted using a predetermined carrier frequency and a predetermined antenna and includes information that at least performs interleaving. . In addition, the received signal is a sub-signal transmitted using the same carrier frequency and the same antenna as the main signal, and is a unit of interleaving even during a period in which the main signal is transmitted. In some cases, sub-signals transmitted in a period shorter than the period to be included are included. The receiving unit 52 converts the frequency of the signal received by the receiving antenna 50 from a radio frequency to an intermediate frequency.

  The quadrature detection unit 76 performs quadrature detection on the intermediate frequency signal converted by the reception unit 52 and outputs a baseband signal. The baseband signal generally includes an in-phase component and a quadrature component, and therefore should be indicated by two signal lines. Here, for the sake of clarity, the signal is indicated by one signal line. . The FFT unit 68 converts the frequency domain signal into a time domain signal by performing FFT on the baseband signal. The deinterleaving unit 72 performs time deinterleaving after performing frequency deinterleaving. The demapping unit 70 performs demapping on the deinterleaved signal, and the decoding unit 74 decodes the demapped signal.

  Here, the processing in the FFT unit 68 corresponds to the IFFT unit 36 in FIG. 2, the processing in the deinterleaving unit 72 corresponds to the processing in the interleaving unit 32 in FIG. 2, and the processing in the demapping unit 70. Corresponds to the processing in the mapping unit 34 in FIG. 2, and the processing in the decoding unit 74 corresponds to the processing in the encoding unit 30 in FIG. Through the above processing, the main signal processing unit 54 extracts information included in the main signal received by the receiving unit 52. The program processing unit 56 reproduces the broadcast video and audio based on the signal decoded by the decoding unit 74. When MPEG2 encoding is performed on the broadcast video and audio, the program processing unit 56 executes MPEG2 decoding. The program processing unit 56 outputs the decoded video information and audio information from the output unit 58. The output unit 58 includes a display and a speaker.

  The determination unit 60 monitors the change in the amplitude of the signal received by the reception unit 52. When the amplitude reduction range is larger than the threshold value, the determination unit 60 detects that a sub signal is included. Here, the threshold value is set so as to correspond to the processing in the insertion unit 12 (not shown), and is set to be larger than the width of the amplitude reduction of the signal subjected to IFFT. Note that the determination unit 60 may perform the above processing on a signal that has been subjected to statistical processing such as averaging. The sub signal processing unit 62 extracts information included in the sub signal when the determination unit 60 detects the presence of the sub signal. Here, the presence of alarm information is extracted based on the presence of the sub-signal itself. The warning unit 64 is configured by an LED or the like, and turns on the LED when the presence of alarm information is extracted by the sub signal processing unit 62.

  In the above description, the receiving device 120 is integrally provided with the warning unit 64 from the reception unit 52. However, these components may not be integrally provided in one apparatus. For example, one device may be configured from the reception unit 52 to the output unit 58, and another device may be configured from the reception unit 52 and the determination unit 60 to the warning unit 64. Here, the main signal is processed by one device, and the sub-signal is processed by another device.

  Operations of the transmission apparatus 100 and the relay apparatus 110 configured as above will be described. FIG. 5 is a flowchart illustrating a procedure of transmission processing in the transmission device 100 and the relay device 110. The insertion unit 12 inputs a main signal (S10). When occurrence of an alarm is detected in the monitoring control unit 20 (Y in S12), the monitoring control unit 20 generates a sub signal (S14), and the insertion unit 12 superimposes the sub signal on the main signal (S16). . On the other hand, when the occurrence of an alarm is not detected in the monitoring control unit 20 (N in S12), the insertion unit 12 outputs the main signal as it is to the transmission unit. The transmission unit 14 transmits a signal from the insertion unit 12 (S18). If the main signal is continued (Y in S20), the process returns to Step 10, but if the main signal is not continued (N in S20), the process is terminated.

  Hereinafter, modified examples will be described. So far, the transmission device 100, the relay device 110, and the reception device 120 included in the digital television broadcasting system have been described. However, in the modification, a specific configuration in which they are connected via a wireless transmission path is described. explain. FIG. 6 shows a configuration of a digital television broadcast system including the transmission device 100, the relay device 110, and the reception device 120. As shown in the figure, the digital television broadcasting system includes a first reception device 110a, a second relay device 110b, a third relay device 110c, and a reception device 120, collectively referred to as a transmission device 100 and a relay device 110. It includes a device 120a and a second receiving device 120b.

  The transmission device 100 corresponds to the transmission device 100 shown in FIG. 1A, and the first to third relay devices 110a to 110c correspond to the relay device 110 shown in FIG. The first receiving device 120a to the second receiving device 120b correspond to the receiving device 120 shown in FIG. In such a configuration, the transmission device 100 transmits a digital broadcast wave, and the first relay device 110a receives the digital broadcast wave from the transmission device 100. The first relay device 110a relays and transmits the digital broadcast wave from the transmission device 100, the second relay device 110b relays and transmits the digital broadcast wave from the first relay device 110a, and the third relay device. 110c relays and transmits the digital broadcast wave from the second relay device 110b. The first receiving device 120a receives the digital broadcast wave from the first relay device 110a, and the second receiving device 120b receives the digital broadcast wave from the second relay device 110b.

  When an alarm occurs in each of the transmission device 100 and the relay device 110, each superimposes a sub signal as described above. When each of the transmission device 100 and the relay device 110 arbitrarily superimposes a sub signal, there are cases where the sub signal overlaps or continues. As a result, a plurality of sub-signals may exist in a period that is a unit of one time interleave. If there are a plurality of sub-signals in one time interleaving unit, even if the receiving apparatus 120 performs deinterleaving and decoding, errors contained in the main signal cannot be corrected, and the reception quality of the main signal deteriorates. To do. That is, the broadcast of the main signal is disconnected by the sub-signal, but viewing is affected if the broadcast is disconnected for a longer period. At this time, the interleaving effect is reduced.

  In order to cope with this, the relay apparatus 110 executes the following processing. The configuration of the relay device 110 is the same type as that of the relay device 110 shown in FIG. The reception unit 24 receives a signal from the transmission device 100 or another relay device 110 and outputs the received signal to the insertion unit 12 as a main signal. Here, the received signal is also formed by the main signal and the sub signal. The monitoring control unit 20 detects the presence of the sub signal by monitoring the amplitude and intensity of the received signal. The detection is performed in the same manner as the processing in the determination unit 60 of FIG. When the insertion unit 12 detects the presence of the sub signal, the insertion unit 12 superimposes the sub signal from the monitoring control unit 20 in a period other than a period that is a unit of interleaving including the sub signal.

  Here, the sub signal from the monitoring control unit 20 corresponds to alarm information generated in the relay device 110. In addition, in order to detect a period other than the period that is a unit of interleaving including the sub-signal, the monitoring control unit 20 may be provided with a counter for recognizing the current timing in the frame. Also, the insertion unit 12 operates so as not to insert a new sub-signal until the timing after the detection of one sub-signal or the timing at which one sub-signal is inserted until the end of the interleave unit period. Also good.

  According to the embodiment of the present invention, even in the period in which the main signal is transmitted, the sub signal is transmitted in a period shorter than the period that is a unit of time interleaving. Sub-signals as alarm information can be transmitted while using the same antenna. Further, since the sub-signal is transmitted in a period shorter than the period that is a unit of time interleaving, it is possible to suppress the deterioration of the reception quality of the main signal. Further, since the sub signal is superimposed on the main signal, a separate communication line for transmitting the sub signal is not required, and the maintenance cost can be reduced. Further, since the sub signal is superimposed on the main signal, the sub signal can be transmitted without stopping the transmission of the main signal. In addition, since the signal strength of the main signal is only reduced in order to transmit the sub signal, simple processing can be realized.

  Also, during the period of transmitting the main signal, the sub-signal is transmitted in a period shorter than the period of interleaving, so the same carrier frequency as the main signal and the same antenna as the main signal are used. However, the sub-signal as alarm information can be received. In addition, since control is performed so that one sub-signal is transmitted in a period that is a unit of time interleaving, the possibility that a plurality of sub-signals are transmitted in a period that is a unit of interleaving can be reduced. Moreover, since the possibility that a plurality of sub-signals are transmitted in a period that is a unit of interleaving is reduced, it is possible to suppress deterioration of the transmission characteristics of the main signal.

  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, time interleaving is performed, and the insertion unit 12 transmits the sub signal in a period shorter than a period that is a unit of time interleaving. However, the present invention is not limited to this, for example, bit interleaving or frequency interleaving is performed instead of time interleaving, and the insertion unit 12 may transmit a sub-signal in a period shorter than a period serving as a unit of bit interleaving or frequency interleaving. Good. According to this modification, the present invention can be applied to various configurations.

  In the embodiment of the present invention, the insertion unit 12 performs the insertion of the sub signal with respect to the intermediate frequency signal. However, the present invention is not limited to this, and for example, the insertion unit 12 may perform insertion of a sub-signal on a radio frequency signal. According to this modification, the present invention can be applied to various configurations of the transmission device 100 and the relay device 110.

  In the embodiment of the present invention, the transmission device 100 and the relay device 110 superimpose the sub signal on the main signal by the insertion unit 12 in order to transmit the sub signal. However, the present invention is not limited to this. For example, the transmission device 100 and the relay device 110 include a switching unit instead of the insertion unit 12, and the switching unit deletes the main signal portion corresponding to the period in which the sub signal should be transmitted from the main signal. By doing so, you may transmit a subsignal also in the period which is transmitting the main signal. Such a switching unit is constituted by a switch and normally operates to output a main signal. On the other hand, when the sub signal is received from the monitoring control unit 20, the switching unit interrupts the output of the main signal and outputs the sub signal. The period in which the sub signal is output in the switching unit corresponds to the period in which the insertion unit 12 superimposes the sub signal in the embodiment and the modification. According to this modification, since the main signal is deleted, only the sub signal can be transmitted in the deleted period. That is, the sub signal may be transmitted while reducing the influence on the main signal.

  In the embodiment of the present invention, the transmission device 100 and the relay device 110 adjust the amplitude of the main signal in order to transmit the sub signal. However, the present invention is not limited thereto, and for example, the transmission device 100 and the relay device 110 may insert a sub signal formed by a signal modulated separately from the main signal by the switching unit. In that case, the OFDM modulation scheme similar to that of the main signal may be applied to the sub signal, or the OFDM modulation scheme may not be applied. Further, information indicating the start of the sub signal, for example, a pattern of “0”, “1”, “0” may be included in the head portion of the sub signal. Further, the identification number of the transmission device 100 to which the sub signal is added or the identification number of the relay device 110 may be added to the sub signal. According to this modification, the amount of information that can be transmitted by the sub signal can be increased.

  In the embodiment of the present invention, the sub signal processed in the transmission device 100, the relay device 110, and the reception device 120 is alarm information. However, the present invention is not limited to this. For example, control information for the main signal may be used. According to this modification, control information can be transmitted while suppressing a decrease in transmission efficiency. That is, the sub signal may be an additional signal with respect to the main signal.

FIGS. 1A to 1B are diagrams illustrating configurations of a transmission device and a relay device according to an embodiment of the present invention. It is a figure which shows the structure of the production | generation part of Fig.1 (a). 3 (a)-(b) shows an overview of the time interleaving performed on the signals processed in the transmission device and the relay device in FIGS. 1 (a)-(b) and the sub-signals inserted in the insertion unit. It is a figure which shows a timing. It is a figure which shows the structure of the receiver which concerns on the Example of this invention. It is a flowchart which shows the procedure of the transmission process in the transmission apparatus and relay apparatus of Fig.1 (a)-(b). It is a figure which shows the structure of the digital television broadcast in which the transmitter of FIG. 1 (a)-(b) and the relay apparatus, and the receiver of FIG. 4 were included.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Generation part, 12 Insertion part, 14 Transmission part, 16 Switching part, 18 Transmission antenna, 20 Monitoring control part, 22 Reception antenna, 24 Reception part, 100 Transmission apparatus, 110 Relay apparatus

Claims (4)

A digital broadcast wave signal from a transmitting device that should transmit a digital broadcast wave or another relay device that should relay a digital broadcast wave, and including a signal containing at least interleaved information as a main signal A receiving unit to
A transmission unit that performs transmission of a digital broadcast wave while using a predetermined carrier frequency and a predetermined antenna for the main signal received by the reception unit ,
The transmitter is
A supervisory control unit for generating a sub-signal including additional information;
An insertion unit that inserts the sub-signal generated in the monitoring control unit into the main signal in a period shorter than the period that is a unit of interleaving even in the period of transmitting the main signal,
The monitoring control unit monitors whether a sub signal has already been inserted in the main signal by the transmitting device or the other relay device by monitoring the main signal received by the receiving unit,
When the monitoring control unit detects that a sub-signal is already inserted in the main signal, the insertion unit is in a period other than a period that is a unit of interleaving in which the detected sub-signal is already included, A relay device , wherein a sub-signal generated in the monitoring control unit is inserted .   The monitoring control unit includes a counter for recognizing the current timing,
  2. The intermediate apparatus according to claim 1, wherein the insertion unit prohibits the insertion of the sub signal from the timing at which the monitoring control unit detects the sub signal until it is behind by a period that is a unit of interleaving. . Claim wherein the transmitting unit, by removing a portion of the main signal corresponding to a period to transmit a sub-signal from the main signal, characterized in that also transmit the sub-signal in a period that is sending the main signal 3. The relay device according to 1 or 2 . 3. The transmission unit transmits a sub signal even in a period in which the main signal is transmitted by superimposing the sub signal on the main signal over a period in which the sub signal is to be transmitted. The relay device described in 1 .

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