JP2021069101A - Transmitter and receiver - Google Patents

Abstract

To enable flexible band allocation to improve frequency utilization efficiency.SOLUTION: A transmitter according to a first aspect is a transmitter to be used for a digital broadcasting system for performing layer transfer of a plurality of layers using a segment structure in which one broadcast channel is divided into a plurality of segments. The transmitter comprises: control signal generation means for generating a transfer control signal for designating band allocation of at least one layer of the plurality of layers in units of quantities smaller than segments; and control signal transmission means for transmitting the transfer control signal to the receiver. Each of the plurality of segments is constituted by a plurality of subcarriers. The transfer control signal designates the band allocation in units of subcarriers or units of divided segments that each are composed of two or more subcarriers, as the quantities smaller than segments.SELECTED DRAWING: Figure 3

Description

The present invention relates to a transmitting device and a receiving device used in a digital broadcasting system.

Next-generation terrestrial broadcasting transmission system that inherits the features of the current ISDB-T system, which is the current terrestrial digital broadcasting system, for higher quality and higher functionality of terrestrial digital broadcasting (hereinafter referred to as "terrestrial digital broadcasting advanced system" Is under study (see, for example, Non-Patent Documents 1 and 2).

In the advanced terrestrial broadcasting system, while inheriting the segment structure and layered transmission function of the ISDB-T system, the introduction of a new signal structure enables multiple services assuming different reception modes such as fixed reception and mobile reception. It improves the flexibility of bandwidth allocation and the flexibility of transmission capacity allocated to partial reception services.

FIG. 1 is a diagram showing a segment structure of an advanced terrestrial broadcasting system. As shown in FIG. 1, in the advanced terrestrial broadcasting system, it is possible to transmit up to three layers with different transmission parameters by using 35 of the 36 divisions of the bandwidth (6 MHz width) of the broadcasting channel. The blocks of the band divided into 35 (6000/36 kHz each) are called in units of segments, and the transmission capacity is distributed to each layer in units of segments.

Of the 35 segments, 9 segments (1.50 MHz width) in the central portion are called a partial reception band, and a signal of layer A, which is a layer for mobile reception, is transmitted within the partial reception band. The number of segments in the A layer can be set within the range of 1 to 9, which enhances the flexibility of the transmission capacity of the A layer. In addition, the partial reception bandwidth has been expanded to 3.5 times that of the ISDB-T method, enhancing the frequency interleaving effect.

On the other hand, there are three hierarchical transmission services in the advanced terrestrial broadcasting system: "highly resistant audio only", "video / audio for mobile reception (about HD)", and "video / audio for fixed reception (UHDTV)". It is being considered to transmit layers.

By providing a layer for transmitting "highly resistant audio only", for example, when viewing "video / audio for mobile reception" in a mobile reception environment, viewing is possible due to changes in level or propagation conditions. If it becomes impossible to continue, by switching the output of the receiver to the layer of "highly resistant audio only", the video will be interrupted, but the audio viewing can be continued.

ARIB STD-B31 "Digital Terrestrial Television Broadcasting Transmission Method", Association of Radio Industries and Businesses NHK Science & Technical Research Laboratories R & D No. 172 P2-P47 2018.11, Internet <URL: https: // www. NHK. or. jp / strl / publica / rd / rd172 / rd172-j. html>

By the way, in the Internet streaming providing service of radio and FM broadcasting, the bit rate of voice is about 48 kbps, and the same bit rate is expected even when the above-mentioned voice service is provided.

In the advanced terrestrial broadcasting system, when a layer is assigned to "highly resistant audio only" and the low bit rate service is provided as described above, the transmission capacity can be set only for each segment, so 1 for the low bit rate service. One segment will be used.

In this case, the segment that transmits "only high-tolerance voice" is filled with NULL except for voice data, which causes a problem that frequency utilization efficiency is lowered.

Therefore, an object of the present invention is to provide a transmitting device and a receiving device that enable flexible band allocation and improve frequency utilization efficiency.

The transmission device according to the first aspect is a transmission device of a digital broadcasting system that transmits a plurality of layers configured by a segment structure in which one broadcasting channel is divided into a plurality of segments, and is among the plurality of layers. A plurality of control signal generating means for generating a transmission control signal for designating a band allocation of at least one layer in a unit finer than a segment unit, and a control signal transmitting means for transmitting the transmission control signal to a receiving device. Each of the segments is composed of a plurality of subcarriers, and the transmission control signal specifies the band allocation in the subcarrier unit or the divided segment unit composed of two or more subcarriers as a unit finer than the segment unit. The gist is to do.

The receiving device according to the second aspect is a receiving device of a digital broadcasting system that transmits a plurality of layers configured by a segment structure in which one broadcasting channel is divided into a plurality of segments, and is among the plurality of layers. A control signal receiving means for receiving a transmission control signal for designating a band allocation of at least one layer in a unit finer than a segment unit is provided, and each of the plurality of segments is composed of a plurality of subcarriers. The gist of the transmission control signal is to specify the band allocation in a subcarrier unit or a divided segment unit composed of two or more subcarriers as a unit finer than the segment unit.

According to the present invention, it is possible to provide a transmitting device and a receiving device that enable flexible band allocation and improve frequency utilization efficiency.

FIG. 1 is a diagram showing a segment structure of an advanced terrestrial broadcasting system. It is a figure which shows the structure of the digital broadcasting system which concerns on 1st and 2nd Embodiment. It is a figure which shows the example of the band allocation which concerns on 1st Embodiment. It is a figure which shows the structure of the transmission device which concerns on 1st Embodiment. It is a figure which shows the structure of the receiving apparatus which concerns on 1st Embodiment. It is a figure which shows the example of the band allocation which concerns on 2nd Embodiment. It is a figure which shows the structure of the transmission device which concerns on 2nd Embodiment. It is a figure which shows the structure of the receiving apparatus which concerns on 2nd Embodiment. It is a figure which compares and shows the number of data carriers with and without segment division. It is a figure which compares and shows the relationship between the number of segments and the transmission capacity with and without the segment division.

An embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are designated by the same or similar reference numerals.

<First Embodiment>
First, the digital broadcasting system according to the present embodiment will be described. The digital broadcasting system according to this embodiment is a system corresponding to the advanced terrestrial broadcasting system.

FIG. 2 is a diagram showing a configuration of a digital broadcasting system 1 according to the present embodiment. As shown in FIG. 2, the digital broadcasting system 1 according to the present embodiment includes a transmission device 100, a reception device 200a for fixed reception, and a reception device 200b for mobile reception. In the following, when the receiving device 200a for fixed reception and the receiving device 200b for mobile reception are not distinguished, they are simply referred to as "reception device 200".

The transmission device 100 performs layered transmission of a plurality of layers by a segment structure in which one broadcasting channel is divided into a plurality of segments. Each of the plurality of segments is composed of a plurality of subcarriers. Each of the plurality of layers has different transmission parameters such as a modulation method and an error correction coding rate. The subcarrier may be simply called a carrier.

The transmission device 100 transmits a plurality of layers having different transmission capacities and transmission tolerances via a broadcast transmission line. In this embodiment, three layers, A layer to C layer, are illustrated as a plurality of layers. For example, the A layer is a layer for mobile reception, and the B layer and the C layer are layers for fixed reception.

The receiving device 200a for fixed reception receives the broadcast wave from the transmitting device 100, and demodulates / decodes the layer for fixed reception. The receiving device 200b for mobile reception receives a broadcast wave from the transmitting device 100, and demodulates / decodes the layer for mobile reception.

FIG. 3 is a diagram showing an example of band allocation according to the present embodiment. Conventionally, the bandwidth of each layer could be allocated only in segment units (see FIG. 1), but in the present embodiment, as shown in FIG. 3, the bandwidth of each layer can be allocated in units finer than the segment unit. ..

In FIG. 3, of the broadcast channel bands (35 segments), the band consisting of 3 segments and α subcarriers is assigned to the A layer, the band consisting of 27 segments and β subcarriers is assigned to the B layer, and 4 An example is shown in which a band consisting of a segment and a γ subcarrier is assigned to the C layer. Here, each of α, β, and γ represents the number of subcarriers for a fraction less than one segment.

As shown in FIG. 3, instead of allocating all layers A to C in subcarrier units, only some of layers A to C are allocated in subcarrier units. You may go. For example, the A layer and the B layer may be allocated in units of subcarriers, and the C layer may be allocated in units of segments.

In the present embodiment, the transmission device 100 generates a transmission control (TMCC: Transmission and Multiplexing Configuration Control) signal that specifies the band allocation of each layer in a unit finer than the segment unit, and transmits the generated TMCC signal to the reception device 200. Send. For the TMCC signal, as a unit finer than the segment unit, the band allocation of each layer is specified in the subcarrier unit or the divided segment unit composed of two or more subcarriers.

In this way, by designating the band allocation of each layer in the subcarrier unit or the divided segment unit composed of two or more subcarriers, flexible band allocation can be enabled and frequency utilization efficiency can be improved.

When specifying in units of subcarriers, the number of subcarriers to be used is determined for each layer, and information indicating the number of subcarriers in each layer (subcarrier number information) is included in the TMCC signal. Alternatively, the number of segments and the number of subcarriers to be fractions may be determined. In this way, the band allocation information regarding the determined number of carriers is transmitted to the receiving device 200 through the TMCC signal. In the example of FIG. 3, when the number of segments and the number of subcarriers to be fractions are determined, the TMCC signals are "A layer: 3 segments and α subcarriers", "B layer: 27 segments and β subcarriers", and "C. Includes band allocation information such as "hierarchy: 4 segments and γ subcarriers".

In this way, the method of determining the number of subcarriers enables highly flexible transmission capacity allocation, but on the other hand, the amount of band allocation information to be transmitted by the TMCC signal increases. Therefore, one segment may be further divided into a plurality of segments, and the bandwidth allocation of each layer may be specified for each divided segment. In this case, information indicating the number of divided segments in each layer (information on the number of divided segments) is included in the TMCC signal. For example, one segment is divided into three, and bandwidth is allocated in units of 1/3 segment.

When specifying the bandwidth allocation of each layer for each subcarrier, it is necessary to divide up to 29365 subcarriers (one of the parameters of 32k FFT), and the amount of information is 19 bits (2 ^ 18) per layer. <29365 <2 ^ 19) is required. Since it is necessary to specify for each layer, the number of bits for three layers is 57 bits. On the other hand, when the band allocation of each layer is specified in 1/3 segment units, the entire transmission band is divided into 105 (35 layers x 3), so the amount of information is 7 bits (2 ^ 6 <105 <. 2 ^ 7), and there are 21 bits for 3 layers.

Next, the configuration of the transmission device 100 according to the present embodiment will be described. FIG. 4 is a diagram showing a configuration of a transmission device 100 according to the present embodiment. In the drawings, interleave is abbreviated as "IL". In the present embodiment, the transmitting device 100 performs a plurality of antenna transmissions using two transmitting antennas. The transmission system corresponding to one transmitting antenna is referred to as "1 system", and the transmitting system corresponding to the other transmitting antenna is referred to as "2 system". For example, the transmitting antenna of the 1st system is a horizontally polarized antenna, and the transmitting antenna of the 2nd system is a vertically polarized antenna.

As shown in FIG. 4, the transmission device 100 includes an input I / F unit 101, a BICM unit 102 (102A to 102C) provided for each layer, and a level adjustment unit 103 (103A to 103C) provided for each layer. ), The system separation unit 104 (104A to 104C) provided for each layer, the layer synthesis unit 105 (105H and 105V) provided for each transmission system, and the time interleaving unit 107 provided for each transmission system. 107H and 107V), the frequency interleaving unit 108 (108H and 108V) provided for each transmission system, the band synthesis unit 109 (109H and 109V) provided for each transmission system, the MISO coding unit 110, and the TMCC. Information bit generation unit 111, synchronization bit generation unit 112, TMCC generation unit 113, pilot generation unit 114, OFDM frame configuration unit 115 (115H and 115V) provided for each transmission system, and for each transmission system. It has an OFDM unit 116 (116H and 116V) and a GI addition unit 117 (117H and 117V) provided for each transmission system.

The input I / F (interface) unit 101 outputs the signals of the three hierarchical frames to the BICM unit 102, outputs the TMCC information to the TMCC information bit generation unit 111 and the pilot generation unit 114, and outputs the LLch frame signal. It is output to the OFDM frame component 115.

The BICM unit 102 performs error correction coding processing (including BCH coding processing and LDPC coding processing) on the signals of each layer output by the input I / F unit 101, and the signal after the error correction coding processing. Is mapped to a carrier symbol. The carrier symbol is a unit of transmission consisting of one OFDM symbol (time direction) and one subcarrier (frequency direction).

The level adjustment unit 103 performs power adjustment processing for each layer (for example, power boost of layer A) on the carrier symbol output by the BICM unit 102, and outputs the carrier symbol after the power adjustment processing to the system separation unit 104. To do.

The system separation unit 104 performs a separation process of separating the carrier symbol output by the level adjustment unit 103 into the carrier symbol of the 1 system and the carrier symbol of the 2 system, and outputs the carrier symbol after the separation process to the layer synthesis unit 105.

The layer synthesizing unit 105 performs a layer synthesizing process on the carrier symbols of each layer of the A layer, the B layer, and the C layer output by the system separation unit 104, and outputs the carrier symbol after the layer synthesizing process to the band dividing unit 106. To do.

The band division unit 106 performs band division processing on the carrier symbol output by the layer synthesis unit 105, and outputs the carrier symbol after the band division processing to the time interleaving unit 107.

The time interleaving unit 107 performs a time interleaving process on the carrier symbol output by the band dividing unit 106, and outputs the carrier symbol after the time interleaving process to the frequency interleaving unit 108.

The frequency interleaving unit 108 performs frequency interleaving processing on the carrier symbol output by the band dividing unit 106, and outputs the carrier symbol after the frequency interleaving processing to the band synthesizing unit 109. In the present embodiment, since subcarriers having different layers may coexist in one segment, the subcarriers that are fractions in each layer are individually interleaved.

The band synthesis unit 109 performs band synthesis processing on the carrier symbol output by the frequency interleaving unit 108, and outputs the carrier symbol after the band synthesis processing to the OFDM frame configuration unit 115V. Specifically, the band synthesis unit 109H outputs the carrier symbol of the 1 system to the OFDM frame configuration unit 115H, and the band synthesis unit 109V outputs the carrier symbol of the 2 system to the OFDM frame configuration unit 115V.

The MISO coding unit 110 performs MISO coding processing on the carrier symbol output by the band synthesis unit 109H, and outputs the carrier symbol after the MISO coding processing to the OFDM frame configuration unit 115V. However, the MISO coding process is a process required when STBC (Space Time Block Coding) or SFBC (Space Frequency Block Coding) is applied. When SDM (Space Division Multiplexing), which expands the transmission capacity by transmitting different information from the transmission antennas of the 1st and 2nd systems, is applied, the MISO coding process is not performed.

The TMCC information bit generation unit 111 generates a TMCC information bit from the TMCC information output by the input I / F unit 101, and outputs the generated TMCC information bit to the TMCC generation unit 113. In the present embodiment, the TMCC information bit includes bandwidth allocation information that specifies the bandwidth allocation of each layer in units of subcarriers or divided segments.

For example, the TMCC information bit includes the number of subcarriers used for each layer. The TMCC information bit may include a combination of the number of segments and the number of subcarriers which are fractions for each layer.

Alternatively, the TMCC information bit includes the number of divided segments used for each layer. The TMCC information bit may include a combination of the number of segments and the number of divided segments for each layer.

The synchronization bit generation unit 112 generates a synchronization bit and outputs the generated synchronization bit to the TMCC generation unit 113.

The TMCC generation unit 113 generates a TMCC from the TMCC information bit output by the TMCC information bit generation unit 111 and the synchronization bit output by the synchronization bit generation unit 112, and outputs the generated TMCC signal to the OFDM frame configuration unit 115.

In the present embodiment, the TMCC information bit generation unit 111 and the TMCC generation unit 113 generate a transmission control signal (TMCC signal) that specifies the band allocation of at least one layer among the plurality of layers in units finer than the segment unit. It constitutes a control signal generation means.

The pilot generation unit 114 generates a pilot (SP: Scattered Pilot) signal based on the TMCC information output by the input I / F unit 101, and outputs the generated SP signal to the OFDM frame configuration unit 115.

The OFDM frame configuration unit 115 includes the carrier symbol output by the band synthesis unit 109 (and the MISO coding unit 110), the SP signal output by the pilot generation unit 114, the LLch signal output by the input I / F unit 101, and the LLch signal. An OFDM frame is constructed by adding a TMCC signal output by the TMCC generation unit 113, and the configured OFDM frame is output to the IFFT unit 116.

The OFDM unit 116 performs an OFDM modulation process on the OFDM frame output by the OFDM frame component unit 115 by the OFDM, and outputs the OFDM frame after the OFDM modulation process to the GI addition unit 117.

The GI addition unit 117 adds a GI (Guard Interval) to the OFDM frame output by the IFFT unit 116, and outputs a signal output 1 which is a transmission signal of the 1 system and a signal output 2 which is a transmission signal of the 2 system.

In the present embodiment, the OFDM frame configuration unit 115, the IFFT unit 116, and the GI addition unit 117 constitute a control signal transmission means for transmitting a transmission control signal (TMCC signal) to the receiving device 200.

Next, the configuration of the receiving device 200 according to the present embodiment will be described. FIG. 5 is a diagram showing a configuration of a receiving device 200 according to the present embodiment. In the drawings, the deinterleave is abbreviated as "DeIL".

As shown in FIG. 5, the receiving device 200 according to the present embodiment includes a receiving unit 201, an FFT unit 202, a TMCC demodulation unit 203, a propagation path estimation unit 204, an equalization unit 205, and a band dividing unit 206. It has a frequency deinterleaved unit 207, a time deinterleaved unit 208, an LLR calculation unit 209, an LDPC decoding unit 210, and a BCH decoding unit 211.

The receiving unit 201 receives the broadcast wave from the transmitting device 100 and outputs an OFDM frame including the TMCC signal to the FFT unit 202.

The FFT unit 202 performs OFDM demodulation processing by FFT on the OFDM frame output by the receiving unit 201, and outputs the signal after the OFDM demodulation processing to the TMCC demodulation unit 203, the propagation path estimation unit 204, and the equalization unit 205. To do.

In the present embodiment, the receiving unit 201 and the FFT unit 202 receive a transmission control signal (TMCC signal) from the transmitting device 100 that specifies the band allocation of at least one layer among the plurality of layers in units finer than the segment unit. It constitutes a control signal receiving means.

The TMCC demodulation unit 203 demodulates the TMCC signal in the signal output by the FFT unit 202. As a result, the TMCC demodulation unit 203 outputs a TMCC information bit including band allocation information that specifies the band allocation of each layer in units finer than the segment unit.

As described above, the TMCC information bit includes the number of subcarriers used for each layer. The TMCC information bit may include a combination of the number of segments and the number of subcarriers which are fractions for each layer. Alternatively, the TMCC information bit includes the number of divided segments used for each layer. The TMCC information bit may include a combination of the number of segments and the number of divided segments for each layer. Such band allocation information is provided to the band division unit 206.

The propagation path estimation unit 204 estimates the propagation path characteristics based on the SP signal in the signal output by the FFT unit 202, and outputs the estimated propagation path characteristics to the equalization unit 205.

The equalization unit 205 performs equalization processing on the signal output by the FFT unit 202 based on the propagation path characteristics output by the propagation path estimation unit 204, and outputs the signal after the equalization processing to the band division unit 206. To do.

The band division unit 206 performs band division processing on the signal output by the equalization unit 205 based on the band allocation information of each layer included in the TMCC information bit, and sets the signal after the band division processing into the frequency deinterleave unit. Output to 207. For example, when the receiving device 200 is a receiving device 200b for mobile reception, the band dividing unit 206 extracts and outputs a signal in the band of the layer for mobile reception.

The frequency deinterleave unit 207 performs frequency deinterleave processing on the signal output by the band division unit 206, and outputs the signal after the frequency deinterleave processing to the time deinterleave unit 208.

The time deinterleave unit 208 performs a time deinterleave process on the signal output by the frequency deinterleave unit 207, and outputs the signal after the time deinterleave process to the LLR calculation unit 209.

The LLR calculation unit 209 calculates the LLR (log-likelihood ratio) from the signal output by the time deinterleave unit 208, and outputs the calculated LLR to the LDPC decoding unit 210.

The LDPC decoding unit 210 performs the LDPC decoding process using the LLR output by the LLR calculation unit 209, and outputs the signal after the LDPC decoding process to the BCH decoding unit 211.

The BCH decoding unit 211 performs BCH decoding processing on the signal output by the LDPC decoding unit 210, and outputs the signal after the BCH decoding processing.

As described above, according to the present embodiment, by designating the band allocation of each layer in the subcarrier unit or the divided segment unit, it is possible to enable flexible band allocation and improve the frequency utilization efficiency.

<Second Embodiment>
Next, the differences between the second embodiment and the first embodiment will be mainly described. FIG. 6 is a diagram showing an example of band allocation according to the present embodiment.

As shown in FIG. 6, the band of the broadcast channel includes a partial reception band used for transmission of layer A, which is a layer for mobile reception. FIG. 6 shows an example in which 5 of the 9 segments constituting the partial reception band are assigned to the mobile reception layer (A layer), and the remaining 4 segments are assigned to the B layer.

In the present embodiment, the layer for mobile reception (layer A) is divided into a plurality of divided layers. Each of the plurality of partition layers has different transmission parameters such as a modulation method and an error correction coding rate.

FIG. 6 shows an example of dividing the mobile reception layer (A layer) into two divided layers, A0 layer and A1 layer. For example, as a service for mobile reception, a new service "highly resistant audio only" is transmitted in the A0 layer, and the same "mobile reception video / audio (about HD)" as in the past is transmitted in the A1 layer. ..

The receiving device 200b for mobile reception receives only the 9 segments constituting the partial receiving band, and demodulates / decodes only the A layer. By dividing the A layer into the A0 layer and the A1 layer, such a narrow band receiving device 200b can also use the two services for mobile reception, so that the mobile reception service can be enhanced.

In the first embodiment, the bandwidth of each layer is allocated in subcarrier units or divided segment units for all layers A to C, but in the second embodiment, the subcarrier unit or divided segment unit is used only for the A layer. Allocate the bandwidth of each division layer with.

Specifically, the transmission device 100 transmits a TMCC signal that specifies the band allocation of each of the plurality of division layers (A0 layer and A1 layer) in the partial reception band in units finer than the segment unit. The receiving device 200 receives this TMCC signal.

Here, the total number of subcarriers in the A0 layer and the A1 layer is limited to an integer number of segments. The number of segments of the B layer and the C layer is also an integer. Since the number of segments in each layer is also transmitted within the TMCC of the advanced terrestrial broadcasting system, the information additionally transmitted using the TMCC is the number of subcarriers or the number of divided segments in the A0 layer.

Since the total number of subcarriers in the A0 layer and the A1 layer is an integer segment, the number of subcarriers or divided segments in the A1 layer is uniquely determined when the number of subcarriers or divided segments in the A0 layer is determined. Further, since the A layer has 9 segments or less, the maximum number of subcarriers or divided segments defined by the A0 layer may be up to 9 segments.

Further, in the TMCC signal, when the band allocation information for transmitting the number of segments of the A0 layer is ALL1 (or ALL0) or the like, the A layer is not divided (that is, the A layer has only one layer). , It is also possible to perform demodulation as before (that is, in units of all hierarchical segments).

On the other hand, when the A layer is divided into the A0 layer and the A1 layer, it is necessary to separately transmit transmission parameters such as a modulation method and an error correction coding rate by TMCC for the A0 layer. In the present embodiment, in order to easily realize modulation and demodulation, it is assumed that the SP arrangement and time interleaving of the A0 layer and the A1 layer are the same.

Next, the configuration of the transmission device 100 according to the present embodiment will be described as being different from the above-described first embodiment. FIG. 7 is a diagram showing a configuration of a transmission device 100 according to the present embodiment.

As shown in FIG. 7, when the SP arrangement and time interleaving of the A0 layer and the A1 layer are the same, the BICM unit 102A0 for the A0 layer is newly added. That is, the transmission device 100 according to the present embodiment is different from the above-described first embodiment in that it has a BICM unit 102A0 for the A0 layer and a BICM unit 102A0 for the A1 layer.

The BICM unit 102A0 performs error correction coding processing on the signal of the A0 layer output by the input I / F unit 101, and maps the signal after the error correction coding processing to the carrier symbol. On the other hand, the BICM unit 102A1 performs error correction coding processing on the signal of the A1 layer output by the input I / F unit 101, and maps the signal after the error correction coding processing to the carrier symbol. Here, the modulation method and error correction coding rate in the BICM unit 102A0 are different from the modulation method and error correction coding rate in the BICM unit 102A1. After that, the A0 layer signal and the A1 layer signal are subjected to the same transmission process and transmitted.

In the present embodiment, the TMCC information bit generation unit 111 generates the TMCC information bit including the band allocation information for designating the band allocation of the A0 layer and the A1 layer in the subcarrier unit or the divided segment unit. For example, the TMCC information bit includes bandwidth allocation information indicating the number of subcarriers or the number of divided segments in the A0 layer.

Further, when the TMCC information bit generation unit 111 does not divide the A layer (that is, when the A layer has only one layer), the band allocation information of the A0 layer is set to ALL1 (or ALL0) or the like, so that A The receiving device 200 may be notified that the hierarchy is not divided.

Further, the TMCC information bit generation unit 111 includes transmission parameters such as the modulation method and error correction coding rate of the A0 layer and transmission parameters such as the modulation method and error correction coding rate of the A1 layer in the TMCC information bits.

Next, the configuration of the receiving device 200 according to the present embodiment will be described as being different from the above-described first embodiment. FIG. 8 is a diagram showing the configuration of the receiving device 200 according to the present embodiment.

As shown in FIG. 8, the receiving device 200 according to the present embodiment performs the same processing as that of the first embodiment until the time interleaving processing. The receiving device 200 according to the present embodiment is different from the above-described first embodiment in that it has an A0 / A1 layer separating unit 212 that separates the signal after the time interleaving process into the A0 layer and the A1 layer.

Further, the receiving device 200 according to the present embodiment has an LLR calculation unit 209 (209A0 and 209A1) provided for each of the A0 layer and the A1 layer, and an LDPC decoding unit 210 (210A0 and 210A0) provided for each of the A0 layer and the A1 layer. It has 210A1) and BCH decoding units 211 (211A0 and 211A1) provided for each A0 layer and A1 layer.

In the present embodiment, the A0 / A1 layer separation unit 212 monitors the received power in the receiving unit 201 and the MER (Modulation Error Radio) of each layer of the A0 layer and the A1 layer in real time, and monitors the A0 layer and the A1 layer. You may switch the output. That is, the A0 / A1 layer separation unit 212 corresponds to a switching means for switching the division layer to be decoded among the plurality of division layers based on the reception state of the plurality of division layers.

The A0 / A1 layer separation unit 212 outputs the signal of "video / audio for mobile reception (about HD)" of the A1 layer when the reception state is good, and outputs the output to the "A0 layer" when the reception state becomes poor. Switch to a "highly tolerant voice only" signal.

For example, when the received power is used as the reception state, the A0 / A1 layer separation unit 212 outputs the “moving reception video / audio (about HD)” signal of the A1 layer when the received power is equal to or higher than the threshold value. On the other hand, if the received power is less than the threshold value, the signal of "highly tolerant voice only" in the A0 layer may be output.

Alternatively, when MER is used as the reception state, the A0 / A1 layer separation unit 212 outputs a signal of "video / audio for mobile reception (about HD)" of the A1 layer when the MER of the A1 layer is less than the threshold value. On the other hand, when the MER of the A1 layer is equal to or higher than the threshold value, the signal of "highly tolerant voice only" of the A0 layer may be output.

As a result, for example, when viewing "video / audio for mobile reception (about HD)" in a mobile reception environment, if viewing cannot be continued due to level fluctuations or changes in propagation conditions, the output of the receiver By switching to the "high-tolerance audio only" hierarchy, the video will be interrupted, but audio viewing can be continued.

FIG. 9 is a diagram showing a comparison of the number of data carriers between the case where the segment is divided and the case where the segment is not divided. The data carrier means a subcarrier (carrier) in which data (data in the A layer to the C layer) is arranged.

As shown in FIG. 9, when the segment is divided (1/3 SEG) in 1/3 segment units, the number of data carriers in one segment (1 SEG) is divided by three. If it is not divisible by 3, it can be dealt with by truncating the decimal point of the number of carriers in the A0 layer. Here, an example of dividing by 3 is shown, but it can also be carried out by dividing into two, four, and five.

FIG. 10 is a diagram showing a comparison of the relationship between the number of segments and the transmission capacity between the case where the segment division according to the present embodiment is performed and the case where the segment division is not performed.

As shown in FIG. 10, when the target transmission capacity of the A0 layer is 30 to 80 kbps, there are only four patterns to be selected in one segment unit, and the transmission tolerance that can be selected is 3.9 to -2. It is .6 dB.

On the other hand, in the case of 1/3 segment unit, it can be seen that the options are increased and the transmission tolerance that can be selected is also widened. Further, since the service can be provided only in the 1/3 segment, the influence on the transmission capacity allocation to other layers such as the A1 layer can be reduced.

<Other Embodiments>
In the above-described embodiment, an example in which the transmitting device 100 performs a plurality of antenna transmissions using a plurality of transmitting antennas has been described, but the transmitting device 100 may be configured to perform a single antenna transmission using a single transmitting antenna. ..

In the second embodiment described above, an example of transmitting "highly resistant voice only" in the A0 layer has been described, but the service transmitted in the A0 layer is not limited to "highly resistant voice only" and is "high". For example, "subtitles only" may be transmitted instead of "resistant audio only".

A program may be provided that causes a computer to execute each process performed by the transmitting device 100 and the receiving device 200. Further, each of the transmitting device 100 and the receiving device 200 may be configured as a semiconductor integrated circuit (chip).

1: Digital broadcasting system 100: Transmitter 101: Input I / F unit 102: BICM unit 103: Level adjustment unit 104: System separation unit 105: Layer synthesis unit 106: Band division unit 107: Time interleaving unit 108: Frequency interleaving unit 109: Band synthesis unit 110: MISO coding unit 111: TMCC information bit generation unit 112: Synchronous bit generation unit 113: TMCC generation unit 114: Pilot generation unit 115: OFDM frame configuration unit 116: IFFT unit 117: GI addition unit 200 : Reception device 201: Reception unit 202: FFT unit 203: TMCC demodulation unit 204: Propagation path estimation unit 205: Equalization unit 206: Band division unit 207: Frequency orthogonal unit 208: Time orthogonal unit 209: LLR calculation unit 210 : LDPC decoding unit 211: BCH decoding unit

Claims (9)

It is a transmission device of a digital broadcasting system that transmits a plurality of layers composed of a segment structure in which one broadcasting channel is divided into a plurality of segments.
A control signal generation means for generating a transmission control signal that specifies a band allocation of at least one layer among the plurality of layers in a unit finer than a segment unit.
A control signal transmitting means for transmitting the transmission control signal to the receiving device is provided.
Each of the plurality of segments is composed of a plurality of subcarriers.
The transmission control signal is a transmission device characterized in that the band allocation is designated in subcarrier units or in divided segment units composed of two or more subcarriers as a unit finer than the segment unit. The first aspect of claim 1, wherein when the band allocation is specified for each subcarrier, the transmission control signal includes subcarrier number information indicating the number of subcarriers allocated to at least one layer. Transmitter. When the band allocation is specified for each of the divided segments, claim 1 or 2 is characterized in that the transmission control signal includes divided segment number information indicating the number of divided segments allocated to the at least one layer. The transmitter described. The band of the broadcast channel includes a partial reception band used for transmission of the layer for mobile reception.
The plurality of layers include a plurality of divided layers obtained by dividing the layer for mobile reception.
The transmission control signal according to any one of claims 1 to 3, wherein the band allocation of each of the plurality of division layers in the partial reception band is specified in a unit finer than the segment unit. The transmitter described. It is a receiving device of a digital broadcasting system that transmits a plurality of layers composed of a segment structure in which one broadcasting channel is divided into a plurality of segments.
A control signal receiving means for receiving a transmission control signal for designating a band allocation of at least one layer among the plurality of layers in a unit finer than a segment unit is provided.
Each of the plurality of segments is composed of a plurality of subcarriers.
The receiving device is characterized in that the transmission control signal specifies the band allocation in a subcarrier unit or a divided segment unit composed of two or more subcarriers as a unit finer than the segment unit. The fifth aspect of claim 5, wherein when the band allocation is specified for each subcarrier, the transmission control signal includes subcarrier number information indicating the number of subcarriers allocated to at least one layer. Receiver. According to claim 5 or 6, when the band allocation is specified for each of the divided segments, the transmission control signal includes information on the number of divided segments indicating the number of divided segments allocated to the at least one layer. The receiver described. The band of the broadcast channel includes a partial reception band used for transmission of the layer for mobile reception.
The plurality of layers include a plurality of divided layers obtained by dividing the layer for mobile reception.
The transmission control signal according to any one of claims 5 to 7, wherein the band allocation of each of the plurality of division layers in the partial reception band is specified in a unit finer than the segment unit. The receiver described. The receiving device according to claim 8, further comprising a switching means for switching the division layer to be decoded among the plurality of division layers based on the reception state of the plurality of division layers.

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