JP2005341195A - Gap filler device, and retransmission method of digital broadcast signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gap filler device capable of retransmitting only a broadcast wave for a broadcast service for partial reception purpose using a mobile terminal or the like among digital broadcast waves comprising a plurality of hierarchical layers without affecting a fixed layer service and to provide a retransmission method of digital broadcast wave. <P>SOLUTION: The gap filler device receives a terrestrial digital broadcast wave adopting the OFDM (Orthogonal Frequency Division Multiplexing) system and divided into 13 segments and extracts one segment for prescribed partial reception purpose from the received terrestrial digital broadcast wave. Then the gap filler device retransmits the extracted one-segment signal to partial reception purpose mobile receivers existing in a particular area (a park, a station and an inside of a train or the like). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gap filler device and a retransmission method for a digital broadcast signal, and in particular, a gap filler for retransmitting a partial reception broadcast wave for a portable terminal in a digital broadcast to a specific area (a park, a station, a train, etc.). The present invention relates to an apparatus and a digital broadcast signal retransmission method.

  In recent years, terrestrial digital broadcasting has been started as an alternative to current terrestrial broadcasting waves. In this terrestrial digital broadcasting system, implementation of gap filler countermeasures is being studied for the purpose of expanding broadcasting service areas and eliminating difficult viewing areas. With this gap filler countermeasure, a retransmission device (relay device) called a gap filler is installed for each area where broadcast waves do not reach.

  As one of such gap filler countermeasures, a gap filler countermeasure technique for the purpose of eliminating difficult viewing areas indoors other than the broadcast service area has been proposed (for example, Patent Document 1).

  As shown in FIG. 5, the technique of Patent Document 1 amplifies a received signal of a terrestrial digital broadcast wave received by a receiving antenna 111 by a predetermined level by an amplifier 113 to generate a retransmission signal, and the retransmission signal is transmitted to the retransmission antenna 114. Are configured to retransmit to the television receiver 121 located indoors.

  With such a configuration, a terrestrial digital broadcast wave can be received indoors by a broadcast receiver 121 having a known indoor reception antenna 122 without being limited by the reception location, and with a simple configuration. It can be realized at low cost.

  By the way, digital terrestrial broadcasting employs an OFDM (Orthogonal Frequency Division Multiplexing) system in which a transmission bandwidth allocated as a transmission path encoding system is divided into 13 segments, and 13 segments are divided into a maximum of 3 layers. For each layer, parameters corresponding to necessary transmission characteristics such as carrier modulation (DQPSK, QPSK, 16QAM, 64QAM) and inner code coding rate are designated. Moreover, it is possible to receive a mobile broadcasting service (so-called partial reception) using a mobile terminal or the like that receives only one central segment of 13 segments. A broadcast service for partial reception using this portable terminal or the like is expected.

JP 2004-112542 A

  As described above, retransmission by the gap filler device is performed for the purpose of expanding the broadcasting service area and resolving difficult viewing areas. On the other hand, by performing retransmission using the gap filler, There was a possibility that an area would become. In particular, when resending with gap filler for partial reception of mobile terminals existing in specific areas (parks, stations, trains, etc.), fixed services are adversely affected in areas where SFN is difficult to see. There was a fear.

  Therefore, the present invention has been invented in view of the above problems, and its object is to provide a gap filler device and a digital broadcast wave capable of retransmitting a broadcast wave of a specific layer without causing SFN difficulty. Is to solve the above-mentioned problem.

  In addition, an object of the present invention is to replay only a broadcast signal for a partial reception broadcast service using a mobile terminal or the like out of a plurality of digital broadcast signals without affecting a service for a fixed layer. An object of the present invention is to provide a gap filler device and a method for retransmitting digital broadcast waves that can be transmitted.

A first invention for solving the above problem is a gap filler device for retransmitting a digital broadcast signal,
Receiving means for receiving a digital broadcast signal composed of a plurality of layers;
Re-transmission means for re-transmitting a signal of a predetermined layer among the digital broadcast signals composed of the plurality of layers.

  According to a second invention for solving the above-mentioned problem, in the first invention, the predetermined hierarchy is a partial reception hierarchy.

  According to a third invention for solving the above-mentioned problem, in the first or second invention, the retransmitting means includes a bandpass filter for extracting a segment of a predetermined layer from the digital broadcast signal composed of the plurality of layers. It is characterized by that.

  According to a fourth invention for solving the above-mentioned problem, in the first or second invention, the retransmitting means demodulates the received digital broadcast signal to perform error correction, and extracts only the data of the layer to be retransmitted. , And means for multiplexing and retransmitting.

  According to a fifth invention for solving the above-mentioned problems, in the first or second invention, the retransmitting means extracts only the data of the layer demodulated and retransmitted the received digital broadcast signal, and then multiplexes and retransmits it. It is a means to transmit, It is characterized by the above-mentioned.

  According to a sixth invention for solving the above-mentioned problem, in any one of the first to fifth inventions, a detection means for detecting whether a received digital broadcast signal includes a layer signal to be retransmitted, and the detection And means for stopping retransmission when the received digital broadcast signal does not include a layer signal to be retransmitted.

A seventh invention for solving the above problem is a retransmission method for retransmitting a digital broadcast signal,
Receiving a digital broadcast signal composed of a plurality of layers;
A step of retransmitting a signal of a predetermined layer among the plurality of layers of digital broadcast signals.

  An eighth invention for solving the above-mentioned problem is characterized in that, in the seventh invention, the predetermined hierarchy is a partial reception hierarchy.

  According to a ninth invention for solving the above-mentioned problem, in the seventh or eighth invention, only a segment of a predetermined layer is extracted from the digital broadcast signal composed of the plurality of layers, and the segment is retransmitted. Features.

  According to a tenth aspect of the present invention for solving the above-mentioned problems, in the seventh or eighth aspect of the invention, the received digital broadcast signal is demodulated and error-corrected. It is characterized by transmitting.

  An eleventh invention for solving the above-mentioned problems is characterized in that, in the seventh or eighth invention, after extracting only the data of the layer for demodulating and retransmitting the received digital broadcast signal, the data is multiplexed and retransmitted. And

  In a twelfth invention for solving the above-mentioned problem, in any one of the seventh to eleventh inventions, the received digital broadcast signal is detected to include a layer signal to be retransmitted, and the received digital broadcast signal is detected. When the signal of the layer to be retransmitted is not included, the retransmission process is stopped.

  The present invention provides a partial reception layer (one segment) from signals received from a plurality of layers (13 segments) when performing retransmission by gap filler for mobile reception to a specific area (park, station, train, etc.). ) Is extracted and gap filler is performed, so that retransmission for mobile reception can be efficiently realized without affecting the fixed segment.

  Even if only the partial reception layer (one segment) is retransmitted, the partial reception layer usually uses a modulation scheme and coding rate that are strong against deterioration of the transmission path, so that it is also affected by SFN difficulty. Hateful.

  Furthermore, in the frequency division multiplexing method, the linearity of the amplifier unit of the retransmitter (gap filler device) and the receiver becomes a problem. However, when transmitting / receiving one segment, the transmission / reception characteristics can be improved. .

  As shown in FIG. 1, the present invention receives an OFDM (Orthogonal Frequency Division Multiplexing) terrestrial digital broadcast wave divided into 13 segments, and receives one segment for receiving a predetermined partial from the received terrestrial digital broadcast wave. To extract. Then, the extracted signal of one segment is retransmitted to a portable receiver for partial reception existing in a specific area (a park, a station, a train, etc.).

  This is a method of extracting one segment for partial reception from an OFDM (Orthogonal Frequency Division Multiplexing) terrestrial digital broadcast wave divided into 13 segments. The extraction method is fine. This is because one segment is assigned to the layer for partial reception (portable receiver), and frequency interleaving is performed only within this one segment, so that it can be extracted by a bandpass filter.

  As another method, an OFDM (Orthogonal Frequency Division Multiplexing) terrestrial digital broadcast wave divided into 13 segments is received, demodulated once, and only one segment for partial reception is extracted and modulated. The method to do may be used.

  In this way, by extracting one segment for partial reception from an OFDM (Orthogonal Frequency Division Multiplexing) terrestrial digital broadcast wave divided into 13 segments and retransmitting it, it is intended for the fixed layer of the area to be retransmitted. Retransmission can be performed to a portable receiver for partial reception without affecting the broadcast service, for example, without affecting SFN obstruction.

  Hereinafter, specific examples of the present invention will be described.

  A first embodiment of the present invention will be described.

  FIG. 2 is a diagram showing the configuration of the gap filler device of Example 1 according to the present invention.

  As shown in FIG. 2, the gap filler device according to the first embodiment includes a receiving antenna 1 that receives an OFDM (Orthogonal Frequency Division Multiplexing) terrestrial digital broadcast wave that is divided into 13 segments, and the receiving antenna 1 receives the terrestrial digital broadcasting wave. A band pass filter 2 for extracting one segment for predetermined partial reception from the terrestrial digital broadcast wave, and an amplifying unit (amplifier) 3 for amplifying the one segment broadcast signal output from the band pass filter 2. And a transmission antenna 4 for retransmitting the broadcast signal.

  The receiving antenna 1 receives a terrestrial digital broadcast wave divided into 13 segments as shown in FIG. This terrestrial digital broadcast wave is for 64QAM carrier modulation, convolutional code r = 3/4 fixed receiver layer, and QPSK carrier modulation, convolutional code r = 1/2 partial reception (portable receiver) 1 layer is assigned to a layer for partial reception (portable receiver), and frequency interleaving is performed only within this 1 segment.

  The band pass filter 2 extracts a band of one segment of a layer for partial reception (portable receiver) from the terrestrial digital broadcast wave received by the receiving antenna 1 as shown in FIG. Since the partial reception layer performs frequency interleaving within one segment as described above, it can be extracted with a band-pass filter for partial reception.

  The amplifying unit 3 amplifies the signal output from the bandpass filter 2 to a predetermined amplitude level, and the amplified signal is retransmitted via the transmission antenna 4.

  As described above, according to the first embodiment, only one segment of the layer for partial reception (portable receiver) is extracted from the reception signal of the terrestrial digital broadcast wave received by the reception antenna 1 by the bandpass filter 2. The signal is amplified by a predetermined level by the amplifier 3 to generate a retransmission signal, and this retransmission signal is retransmitted by the retransmission antenna 4 toward a specific area (park, station, train interior, etc.).

  This allows partial reception (portable reception) that exists in a specific area (park, station, train, etc.) without affecting services for fixed receivers that exist in a specific area (park, station, train, etc.). ) Can be retransmitted.

  In the gap filler device of the first embodiment described above, the digital broadcast wave is received by the antenna and retransmitted. However, the means for receiving the digital broadcast signal is not limited to this. For example, the digital broadcast signal is transmitted by wire or the like. It is also possible to receive and retransmit.

  A second embodiment of the present invention will be described.

  In the first embodiment described above, only the partial reception layer is extracted from the received digital broadcast wave by the band-pass filter and retransmitted. This can be applied in the case where frequency interleaving is performed only in the partial reception layer, for example, frequency interleaving is performed only in one segment. However, there are cases where the layer to be retransmitted is only within the layer and frequency interleaving is not performed. Therefore, in the second embodiment, even in such a case, in order to be able to retransmit, after demodulating the received digital broadcast wave, only a necessary layer is extracted, remodulated, and retransmitted. An example will be described.

  FIG. 3 is a block diagram showing the configuration of the second embodiment.

  The gap filler apparatus according to the second embodiment includes a receiving antenna 11, a tuner 12, a demodulating unit 13, an error correcting unit 14, decoding units 15 and 16, a partial receiving layer extracting unit 17, a multiplexing processing unit 18, and the like. , A modulation unit 19, a transmission unit 20, and a transmission antenna 21.

  A reception signal received by the reception antenna 11 is supplied to the tuner 12. Here, a desired channel is selected to obtain an IF band OFDM signal (hereinafter referred to as an OFDM-IF signal). This OFDM-IF signal is supplied to the demodulator 13. The demodulator 13 demodulates the digital broadcast signal by subjecting the OFDM-IF signal to FFT (Fast Fourier Transform) processing.

  The digital broadcast signal obtained by this demodulation processing is subjected to error correction by the error correction unit 14, thereby restoring data damaged by noise or fading during transmission. The error-corrected digital broadcast signal is divided into a TS signal that is a broadcast content of a program, a TMCC (Transmission and Multiplexing Configuration Control) signal that is a broadcast transmission control signal, and an AC (Auxiliary Channel) signal. Are supplied to the TS decoding unit 15 and the TMCC & AC decoding unit 16, respectively.

  The TS signal is supplied to the TS decoder 15 for decoding. Also, the TS decoding unit 14 regenerates layer information not directly included in the TS signal (broadcast wave) from the TS transmission pattern and the like, and supplies it to the partial reception layer extraction unit 17.

  The partial reception layer extraction unit 17 extracts only partial layer data from the regenerated data and supplies the extracted data to the multiplexing processing unit 18.

  On the other hand, the TMCC signal and the AC signal are decoded by the TMCC & AC decoding unit 16 and supplied to the multiplexing processing unit 18.

  The multiplexing processing unit 18 time-division multiplexes the reconstructed TS signal, TMCC signal, and AC signal, and supplies them to the modulation unit 19.

  The modulation unit 19 performs OFDM modulation on the multiplexed signal and supplies the modulated signal to the transmission unit 20.

  The transmission unit 20 amplifies the OFDM modulated signal with a predetermined amplification degree, and retransmits the retransmission signal to a specific area (a park, a station, a train interior, etc.) via the transmission antenna 21.

  Thereby, it is possible to perform retransmission of a layer for partial reception (portable receiver) without affecting services for fixed receivers existing in a specific area (park, station, train, etc.).

  In the above-described embodiment, the error correction unit 14 performs error correction. However, the error correction unit 14 may perform decoding without error correction and supply the decoded data to the partial reception layer extraction unit 17 and the multiplexing processing unit 18. good.

  In the gap filler device of the second embodiment described above, the digital broadcast wave is received by the antenna and retransmitted. However, the means for receiving the digital broadcast signal is not limited to this, and for example, the digital broadcast signal is transmitted by wire or the like. It is also possible to receive and retransmit.

  In the first and second embodiments described above, the description has been made on the assumption that the received digital broadcast signals are all composed of a plurality of layers.

  However, in the actual broadcast service, the digital broadcast signal does not necessarily include the hierarchy to be retransmitted in all time zones. For example, there is a case where a partial reception service is performed only during a specific time period in the broadcast time of one day. In this case, the digital broadcast signal is composed of a plurality of layers including a partial reception layer in a specific time zone, but does not include a partial reception layer in other time zones. Therefore, it is not only wasteful to retransmit a signal that does not include the layer to be retransmitted, but it may adversely affect receivers in other layers.

  Thus, in the third embodiment, an example will be described in which retransmission is performed by checking whether a received digital broadcast signal includes a layer to be retransmitted.

  FIG. 4 is a block diagram showing the configuration of the third embodiment. In addition, about the thing of the structure similar to the Example mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  The gap filler device according to the third embodiment includes a TMCC information demodulation detection unit 30 and a retransmission stop processing unit 31 in addition to the gap filler device according to the first embodiment.

  The TMCC information demodulation detection unit 30 demodulates a transmission and multiplexing configuration control (TMCC) signal from the received digital broadcast wave, detects layer information included in this information, and determines whether there is a partial reception layer. Then, the presence / absence of the partial reception layer is output to the retransmission stop processing unit 31.

  The retransmission stop processing unit 31 receives the information on the presence / absence of the partial reception layer from the TMCC information demodulation detection unit 30, and outputs the output from the bandpass filter 2 when the partial reception layer is included in the digital broadcast wave. Is output to the amplifying unit 3 as it is. On the other hand, when the partial reception layer is not included in the digital broadcast wave, the output from the bandpass filter 2 is not output to the amplification unit 3.

  As a result, when the partial reception layer is not included in the digital broadcast wave, it is not retransmitted, so that unnecessary processing is not performed and receivers in other layers are not adversely affected.

  In the third embodiment, the TMCC information demodulation detection unit 30 and the retransmission stop processing unit 31 are added to the configuration of the above-described first embodiment. However, the same operation is performed even in the configuration of the second embodiment. It is possible. For example, the TMCC & AC decoding unit 16 determines the presence / absence of a partial reception layer, and based on this information, when the digital broadcast wave includes a partial reception layer, the transmission unit 20 retransmits the signal of the partial reception layer. When the digital broadcast wave is transmitted and the partial reception layer is not included, the retransmission can be stopped.

FIG. 1 is a diagram for explaining an embodiment of the present invention. FIG. 2 is a diagram showing the configuration of the first embodiment of the present invention. FIG. 3 is a diagram showing the configuration of the second embodiment of the present invention. FIG. 4 is a diagram showing the configuration of the third embodiment of the present invention. FIG. 5 is a diagram for explaining the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reception antenna 2 Bandpass filter 3 Amplification part 4 Retransmission antenna 11 Reception antenna 12 Tuner 13 Demodulation part 14 Error correction part 15,16 Decoding part 17 Partial reception hierarchy extraction part 18 Multiplexing process part 19 Modulation part 20 Transmission part 21 Transmission Antenna 30 TMCC information demodulation detection unit 31 Retransmission stop processing unit

Claims (12)

A gap filler device for retransmitting a digital broadcast signal,
Receiving means for receiving a digital broadcast signal composed of a plurality of layers;
A gap filler device comprising: a retransmission unit configured to retransmit a signal of a predetermined layer among the digital broadcast signals including the plurality of layers.   The gap filler device according to claim 1, wherein the predetermined hierarchy is a partial reception hierarchy.   The gap filler device according to claim 1 or 2, wherein the re-transmission unit includes a band-pass filter that extracts a segment of a predetermined layer from the digital broadcast signal including the plurality of layers.   The re-transmission means is means for performing error correction by demodulating the received digital broadcast signal, extracting only the data of the layer to be re-transmitted, and multiplexing and re-transmitting the data. 2. The gap filler device according to 2.   3. The gap according to claim 1, wherein the retransmission means is means for demodulating the received digital broadcast signal and extracting only the data of the layer to be retransmitted, and multiplexing and retransmitting the data. Filler device. Detecting means for detecting whether the received digital broadcast signal includes a layer signal to be retransmitted;
6. The method according to claim 1, further comprising means for stopping retransmission when a detection result of the detection means does not include a signal of a layer to be retransmitted in the received digital broadcast signal. A gap filler device according to claim 1. A retransmission method for retransmitting a digital broadcast signal,
Receiving a digital broadcast signal composed of a plurality of layers;
A method for retransmitting a digital broadcast signal, comprising: retransmitting a signal of a predetermined layer among the digital broadcast signals having a plurality of layers.   The method of claim 7, wherein the predetermined layer is a partial reception layer.   9. The method of retransmitting a digital broadcast signal according to claim 7, wherein only a segment of a predetermined layer is extracted from the digital broadcast signal having a plurality of layers, and the segment is retransmitted.   9. The digital broadcast signal according to claim 7 or 8, wherein the received digital broadcast signal is demodulated to perform error correction, and after extracting only data of a layer to be retransmitted, the data is multiplexed and retransmitted. Resend method.   9. The method of retransmitting a digital broadcast signal according to claim 7 or 8, wherein only the data of the layer to be demodulated and retransmitted is extracted and then multiplexed and retransmitted.   Detecting whether a received digital broadcast signal includes a layer signal to be retransmitted, and stopping a retransmission process when the received digital broadcast signal does not include a layer signal to be retransmitted The method for retransmitting a digital broadcast signal according to any one of claims 7 to 11.

Images