JP2003304510A - Digital broadcast system, digital broadcast transmitter, and digital broadcast receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital broadcast system, a digital broadcast transmitter, and a digital broadcast receiver capable of enhancing the performance of reception by a mobile body by reducing a data error even on the occurrence of strong fading or the like in the case of receiving data by the mobile body employing a small-sized mobile apparatus or the like. <P>SOLUTION: The digital broadcast transmitter 1 of a digital broadcast system multiplexes prescribed data of digital broadcast data to two layers or more (e.g. a layer 1 and a layer 2) among a plurality of layers (layers 1 to 3) and transmits the resulting signal. Than the digital broadcast receiver 14 of the digital broadcast system composes multiplexed data of each of the layers (e.g. the layers 1 and 2) to apply signal processing to the composed data. Thus, a time diversity effect can be obtained between the layers and the reception characteristic under a fading environment can be enhanced. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcasting system, a digital broadcasting transmitter and a digital broadcasting receiver for terrestrial digital television broadcasting and terrestrial digital audio broadcasting.

[0002]

2. Description of the Related Art Currently, digitization of television broadcasting and radio broadcasting is being promoted, and terrestrial digital television broadcasting and terrestrial digital audio broadcasting will be realized following the digitization of satellite broadcasting. .

Broadcasting systems of terrestrial digital television broadcasting and terrestrial digital audio broadcasting are described in "Technical conditions of terrestrial digital television broadcasting system" in the report of the Digital Broadcasting System Committee of the Telecommunications Technology Council, and electrical It is common to comply with the "technical conditions for terrestrial digital audio broadcasting systems" reported by the Communications Technology Council. Therefore, it follows that here as well.

FIG. 10 is a diagram showing a configuration example of a conventional digital broadcasting system. As shown in FIG. 10, this digital broadcasting system includes a digital broadcasting transmitter 1 and a transmission line 1 for transmitting a broadcasting signal output from the digital broadcasting transmitter 1.
3 and a digital broadcast receiver 14.

The digital broadcast transmitter 1 receives an MPEG2 (Moving Picture Experts Gross) input from an input terminal 2.
up phase 2) or T compressed by MPEG4 system
A TS multiplexing unit 3 that multiplexes S (Transport Stream) packets in a time division manner, and reads / writes the multiplexed TS packets.
Outer coding unit 4 for adding error correction code such as Solomon code
And a layer division unit 5 that divides the outer-coded TS packet into each layer (here, three layers as an example). The layers will be described later.

The digital broadcast transmitter 1 further includes inner coding / modulation units 6, 7 and 8 for performing convolutional coding of signals and modulation such as phase shift keying for each hierarchy, and inner coding / modulation for each hierarchy. The layer combining unit 9 that collects the signals from the modulators 6 to 8, the time interleaving unit 10 that rearranges the time data of the output signals from the layer combining unit 9 to equalize the transmission path errors, and the time interleaving unit 10 The output signal is further subjected to OFDM (Orthogonal Frequency) modulation data of each carrier output from the frequency interleaving unit 11 that performs data rearrangement in the frequency space.
Division Multiplex) signal and outputting it to the transmission path 13 to the transmission path 13, and an IFFT (Inverse Fast Fourier Transform) section 12, a pilot signal for detecting transmission path distortion, and a modulation method / coding method / interleave length of each layer. TMCC (Tran which is a signal indicating the signal format of
smission and Multiplexing Configuration Control)
A pilot / TMCC addition unit 26 for adding a signal is provided.

On the other hand, the digital broadcast receiver 14 has an FFT (Fast Fourier Transform) section 15 for decomposing the OFDM signal received from the transmission path 13 into modulated data for each carrier, and a TCC for extracting the TMCC signal from the data after the FFT.
The MCC demodulation units 27 and 16 are a pilot demodulation unit 16 that corrects transmission channel distortion for data after FFT, a frequency deinterleave unit 17 and a time deinterleave unit 18 that rearrange data rearranged on the transmission side, for each layer. A layer division unit 19 for extracting data into a demodulation unit, a demodulation / inner code decoding unit 20 for performing demodulation and inner code decoding (Viterbi decoding) for each layer,
21, 22 and the TS reproducing unit 23 that rearranges the decoded data for each layer into the original TS packet, and the TS reproducing unit 2
Outer code decoding unit 24 is provided which performs outer code decoding on the output from 3 and outputs a signal from output terminal 25.

Next, the operation of this digital broadcasting system will be described. In the terrestrial digital television broadcasting system and the terrestrial digital audio broadcasting system, the encoded video / audio data is MPEG2 or MPE.
After compression by the G4 method, time division multiplexing is performed to generate a TS packet, and the TS packet is transmitted by the OFDM method. At this time, the data to be transmitted is layered as necessary.

In the digital broadcasting system shown in FIG. 10, TS packets input in parallel from the input terminal 2 are time-division multiplexed in the TS multiplexer 3 and error correction codes are added in the outer encoder 4. The outer-coded TS packet is then divided into layers by packet in the layer division unit 5.

For example, in the broadcasting system defined in the above "Technical conditions of terrestrial digital television broadcasting system", hierarchical transmission is allowed, and different modulation systems are provided for each layer (up to 2 layers or 3 layers). It is said that transmission speed and error resilience can be added. The term "hierarchy" as used herein refers to each group when a predetermined frequency bandwidth is divided into a plurality of groups in the frequency domain of a signal to be transmitted and the information is assigned to each of them. Specifically, in the above method, the frequency band of 5.6 MHz width may be divided into 13 segments, and one or a plurality of segments may be divided into one layer.

The method of dividing the TS packet into each layer differs depending on the application. As an example of the application, for example, important information such as program configuration information is assigned to the layer 1
And a modulation scheme / internal coding scheme having a low data transmission rate but a high error resistance is selected for layer 1. On the other hand, for example, video information and audio information are assigned to layers 2 and 3, respectively, and a modulation method / internal coding method that emphasizes data transmission rate rather than error resilience is selected for layers 2 and 3. A convolutional code, for example, may be adopted as the inner coding method so that the coding rate can be selected by puncturing. The modulation method is, for example, QPSK (Quadrature Phase Shift Keyin).
g) and 16QAM (Quadrature Amplitude Modulation)
Etc. may be adopted.

The respective signals encoded and modulated in this way are combined again by the hierarchical combining unit 9 into serial data in the time domain, and then input to the time interleaving unit 10 where the TS packets are rearranged in time. (Ie time interleaving) is performed. Time interleaving is performed on the transmission line 13.
Digital broadcast receiver 1 that disperses errors that are likely to occur in
4 is performed for effective error correction. Note that the time interleave unit 10 can also select the time interleave length for each layer.

The term "time interleave length" as used herein refers to an amount that defines a rearrangement time range when rearranging adjacent data in the time sequence before rearrangement. Specifically, the digital broadcast transmitter 1 side sequentially writes the data of each continuous TS packet in the row direction of the n-row m-column matrix, reads it in the column direction, sends it to the transmission path 13, and sends it to the digital broadcast receiver 14 side. And received consecutive T
When S packets are sequentially written in the column direction of an n-row m-column matrix and read in the row direction (that is, when rows and columns are converted and interleaved), the values of n and m both correspond to the time interleave length. .

Generally, if the time interleave length is increased,
Since the degree of data distribution is high, the reception condition of a receiver such as a mobile body is not easily changed. However, on the other hand, since the degree of dispersion is high, it takes time for the rearrangement process on the receiver side, resulting in a large transmission delay. Therefore, the time interleave length is appropriately set according to the characteristics of the signal to be transmitted, the purpose of transmission, and the like.

The signals thus time-interleaved are input to the frequency interleaving unit 11, and data rearrangement (frequency interleaving) is also performed in the frequency space. Then, the frequency interleaved signal is
It is converted into an OFDM signal by the T section 12 and sent to the transmission path 13. At this time, a pilot signal and a TMCC signal for detecting transmission path distortion are added by the pilot / TMCC adding unit 26.

Further, in the IFFT unit 12, a guard interval signal is added to the OFDM signal in order to avoid the influence of multipath in the transmission line 13, but it is not described here because it is irrelevant to the present invention.

The OFDM signal transmitted through the transmission line 13 is received by the digital broadcast receiver 14. In the digital broadcast receiver 14, first, the FFT unit 15 decomposes the OFDM signal into carriers having different frequency bands. Then, the transmission path distortion of the decomposed signal is the pilot demodulation unit 16
Is corrected in. Also, the TMC in the decomposed signal
The C signal is demodulated by the TMCC demodulation unit 27.

The signals for each carrier thus obtained are input to the frequency deinterleaving unit 17, and data rearrangement is performed by a process reverse to the process in the frequency interleave unit 11 of the digital broadcast transmitter 1. Similarly, in the time deinterleave unit 18, the rearrangement is performed by a process reverse to the process in the time interleave unit 10 of the digital broadcast transmitter 1. As a result, the error generated in the transmission line 13 can be dispersed and the error correction can effectively function. This rearrangement is performed for each layer according to the interleave length set for each layer in the digital broadcast transmitter 1.

The signal for each carrier obtained in this way is divided into each layer by the layer division unit 19, and the modulation method and inner coding method (convolutional coding etc.) for each layer adopted at the time of transmission. ) According to the above)
It is demodulated and decoded by 0, 21, 22. Then, the data of each layer is arranged in the TS reproducing section 23 in the order of transmission, and the outer code decoding section 24 performs error correction processing by the Reed-Solomon code or the like and outputs it from the output terminal 25.

The operation of the time interleaving unit 10 will be described in detail with reference to FIG. Of the original data in which the TS packets are arranged in the time order such as A, the TS packets at a predetermined time position are rearranged by the time interleaving unit 10 to generate rearranged data such as B. Then, this rearranged data is sent to the transmission line 13.

C indicates a state in which a burst error ER has occurred in the rearranged data on the transmission line 13. When the data is rearranged by the time deinterleaver 18, the data becomes as in D, and the burst errors are dispersed. Therefore, error correction decoding can be effectively performed in a stage subsequent to the time deinterleave unit 18.

Various time interleaving methods have been proposed. For example, in the case of "technical conditions of terrestrial digital audio broadcasting method", the convolutional interleaving method is used.

[0023]

In the terrestrial digital television broadcasting system and the terrestrial digital audio broadcasting system, error resilience and time interleave length can be selected for each layer, so that some layers are suitable for mobile reception. The method can be set. For this reason, although mobile reception is feasible, in the case of reception with a small mobile device, the size of the antenna is limited and strong fading occurs, so that sufficient reception in a weak electric field area is possible. Performance may not be secured in some cases. In addition, it is difficult to expect an improvement effect due to antenna diversity used in ordinary mobile reception in a small portable device due to the size limitation.

Therefore, an object of the present invention is to reduce the number of data errors and improve the performance of mobile reception even if strong fading occurs during mobile reception using a small portable device or the like. It is to provide a broadcasting system, a digital broadcasting transmitter, and a digital broadcasting receiver.

[0025]

According to a first aspect of the present invention, a plurality of layers are defined by dividing a predetermined frequency bandwidth in the frequency domain of a signal to be transmitted, and at least two of the plurality of layers are defined. A digital broadcast transmitter that multiplexes and transmits predetermined data included in digital broadcast data to the above layers, and receives the predetermined data that is multiply assigned and receives one data from the received data of each layer. And a digital broadcast receiver that performs signal processing of the digital broadcast data by combining the above.

The invention described in claim 2 is the digital broadcasting system according to claim 1, wherein the digital broadcasting data is composed of a plurality of packets which are time-division multiplexed, and the digital broadcasting transmitter comprises: The digital broadcast data is time-interleaved for each of the at least two or more layers, and the digital broadcast data is time-deinterleaved for each of the at least two or more layers in the digital broadcast receiver. Interleaving processing is performed, and in the time interleaving processing, the time interleaving length, which is a quantity that defines a rearrangement time range when rearranging adjacent data in a temporal order before rearrangement, has at least two or more layers. Is a different digital broadcasting system for each layer.

According to a third aspect of the present invention, in the digital broadcasting system according to the first aspect, the combining performed in the digital broadcasting receiver is selective combining, maximum ratio combining or equal gain combining. It is a broadcasting system.

The invention according to claim 4 is the digital broadcasting system according to claim 3, wherein the selective combining calculates the power of each of the predetermined data assigned to multiplex, and the value of the power is calculated. It is a digital broadcasting system that is performed by selecting a large one.

The invention according to claim 5 is the digital broadcasting system according to claim 3, wherein in the digital broadcasting transmitter, an outer code for error correction is added to the predetermined data, In the digital broadcast receiver, the outer code of the predetermined data is decoded, and the selective combining is performed in accordance with the decoding of the outer code of each of the predetermined data multiply assigned. It is a digital broadcasting system that is performed based on information about the degree.

The invention according to claim 6 is the digital broadcasting system according to claim 3, wherein in the digital broadcasting transmitter, the predetermined data is a signal indicating a signal format of each layer. (Transmission a
nd Multiplexing Configuration Control) signal is added, the TMCC signal of the predetermined data is read in the digital broadcast receiver, the transmission state of the TMCC signal is determined from the amplitude, and the selective combining is assigned to multiplex. The digital broadcasting system is performed based on the transmission state of the TMCC signal of each of the given predetermined data.

The invention according to claim 7 is the digital broadcasting system according to claim 3, wherein in the digital broadcasting transmitter, the predetermined data is subjected to inner coding for error correction, In digital broadcast receivers,
Decoding of the inner code of the predetermined data is performed, and the selective combining is performed based on information about the degree of error calculated with the decoding of the inner code of each of the predetermined data that is multiply assigned. It is a digital broadcasting system that is performed.

The invention described in claim 8 is the digital broadcasting system according to claim 3, wherein the digital broadcasting data is composed of a plurality of time-division multiplexed packets, and the selective combining is performed for each packet. In the digital broadcasting system, the non-selected layer data of the predetermined data that are multiplexed and assigned are replaced with null packets in which invalid information is recorded.

According to a ninth aspect of the present invention, a plurality of layers are defined by dividing a predetermined frequency bandwidth in the frequency domain of a signal to be transmitted, and at least two of the plurality of layers are defined.
It is a digital broadcast transmitter that multiplexes and transmits predetermined data included in digital broadcast data to one or more layers.

The invention described in claim 10 is the digital broadcast transmitter according to claim 9, wherein the digital broadcast data is composed of a plurality of time-division multiplexed packets, and , Said at least 2
A time interleaving process is performed for each layer of two or more layers, and in the time interleaving process, a time interleaving length that is a quantity that defines a time range for sorting when adjacent data is sorted in a temporal order before sorting. Is a digital broadcast transmitter that differs for each of the at least two or more layers.

According to an eleventh aspect of the invention, a plurality of layers are defined by dividing a predetermined frequency bandwidth in the frequency domain of the transmission signal, and at least two or more layers of the plurality of layers are digitally broadcast. Predetermined data included in the data is multiply assigned, the predetermined data that is multiply assigned is received, and 1 is selected from the received data of each layer.
It is a digital broadcast receiver that synthesizes two data and performs signal processing of the digital broadcast data.

The invention described in claim 12 is the digital broadcast receiver according to claim 11, wherein the digital broadcast data is composed of a plurality of packets that are time-division multiplexed, and at least two or more of them are included. A time interleaving process is performed for each hierarchical layer, and in the time interleaving process, a time interleaving length that is a quantity that defines a time range for sorting when adjacent data is sorted in a temporal order before sorting. Is different for each of the at least two or more layers, and is a digital broadcast receiver for performing time deinterleaving processing on the digital broadcast data for each of the at least two or more layers.

The thirteenth aspect of the present invention is the digital broadcast receiver according to the eleventh aspect, wherein the combining is selective combining, maximum ratio combining or equal gain combining.

The invention as set forth in claim 14 is the digital broadcast receiver as set forth in claim 13, wherein the selective combination is
It is a digital broadcast receiver that calculates the power of each of the predetermined data that is multiply assigned and selects the one with a larger power value.

The invention described in claim 15 is the digital broadcast receiver according to claim 13, wherein the predetermined data is provided with an outer code for error correction, and the predetermined data of the predetermined data is added. Decoding the outer code, the selective combining,
It is a digital broadcast receiver that performs it based on information about the degree of error calculated with the decoding of the outer code of each of the predetermined data that is multiply assigned.

The sixteenth aspect of the present invention is the digital broadcast receiver according to the thirteenth aspect, wherein the predetermined data is a signal indicating a signal format of each layer.
CC (Transmission and Multiplexing Configuration)
Control) signal is added, the TMCC signal of the predetermined data is read, and the TM
The transmission state of the CC signal is discriminated, and the selective combining is performed on the TM of each of the predetermined data allocated in multiple.
It is a digital broadcast receiver that performs based on the transmission state of a CC signal.

According to a seventeenth aspect of the present invention, in the digital broadcast receiver according to the thirteenth aspect, the predetermined data is internally coded for error correction, and the predetermined data of the predetermined data is recorded. A digital broadcast receiver that performs decoding of the inner code and performs the selective combining based on information about the degree of error calculated with the decoding of the inner code of each of the predetermined data that is multiply assigned. is there.

The invention as set forth in claim 18 is the digital broadcast receiver as set forth in claim 13, wherein the digital broadcast data is composed of a plurality of packets which are time division multiplexed, and the selective combining is performed. This is a digital broadcast receiver which is performed for each packet and replaces data of a layer that is not selected among the predetermined data that is multiply allocated with a null packet in which invalid information is recorded.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION <First Embodiment> The present embodiment is a digital broadcast transmission in which predetermined data included in digital broadcast data is multiplexed and transmitted to at least two or more layers of a plurality of layers. And a digital broadcast receiver that performs signal processing of digital broadcast data by synthesizing one data from the data of each layer assigned in multiplex. By this means, it is possible to obtain a time diversity effect between layers and improve reception characteristics in a fading environment.

FIG. 1 is a diagram showing a digital broadcasting system according to the present embodiment. As shown in FIG. 1, this digital broadcasting system includes a digital broadcasting transmitter 1 and a transmission line 1 for transmitting a broadcasting signal output from the digital broadcasting transmitter 1.
3 and a digital broadcast receiver 14. It should be noted that, of the digital broadcast transmitter 1 and the digital broadcast receiver 14, elements having the same functions as those of the digital broadcast system of FIG. 10 are designated by the same reference numerals.

The digital broadcast transmitter 1 in the present embodiment receives the output of the TS packet of each layer data from the layer dividing unit 5, and selects one of the three layers (layer 1 to layer 3) as layer 1 and layer 2. , Predetermined data (for example, video information) of the digital broadcasting data is multiplexed, and other digital broadcasting data (for example, audio information) is allocated to the layer 3, and the inner coding / modulation units 6 of the layers 1 to 3 are allocated. 8 to 8 is further provided.

In the digital broadcast receiver 14 according to the present embodiment, among the output signals of the time deinterleaving unit 18, the data of the layers 1 and 2 that are multiply allocated are combined into one data layer. It further includes a synthesizing unit 29a that outputs the data to the unit 19 and outputs the other digital broadcast data of layer 3 to the layer dividing unit 19 as they are.

The rest of the configuration is similar to that of the digital broadcasting system shown in FIG. 10, and therefore its explanation is omitted.

Next, the operation of this digital broadcasting system will be described. In the present embodiment, layers 1 and 2 of layers 1 to 3 are used for transmitting packets of the same digital broadcast data (for example, video information), and layer 3 is used for other digital broadcast data (for example, audio information). The case of using for packet transmission will be taken as an example. In the following, Tier 1
Further, the packet assigned to the layer 2 is referred to as first data, and the packet assigned to the layer 3 is referred to as second data to distinguish it from the layer 1, layer 2, and layer 3 which are layer divisions of actual internal processing. .

The TS packet input from the input terminal 2 of FIG. 1 is time-division multiplexed by the TS multiplexer 3 and the outer encoder 4 adds an error correction code such as Reed-Solomon code. The outer coded TS packet is then divided into first or second data for each packet in the layer dividing unit 5.

In the digital broadcasting system of FIG. 10, since different types of digital broadcasting data are assigned to layers 1 to 3, the layer dividing section 5 outputs three signals. However, in the present embodiment, since there are two types of data to be transmitted, the first and second data, in the digital broadcasting system of FIG. 1, the hierarchical division unit 5 only outputs two signals.

TS divided into first or second data
The packet is input to the layer selection unit 28 and is distributed to any of the inner coding / modulation units 6 to 8 for each layer in the subsequent stage.

The TS packet of the first data input to the layer selection unit 28 is passed to both the inner coding / modulation unit 6 of the layer 1 and the inner coding / modulation unit 7 of the layer 2. On the other hand, the TS packet of the second data is passed to the inner coding / modulation unit 8 of Layer 3. The TS of the second data (layer 3)
Since the packet is subjected to signal processing in the same manner as in the case of the digital broadcasting system in FIG. 10, the following description will be omitted. Below, T of the first data (layer 1 and layer 2)
The signal processing of the S packet will be described.

The TS packet of the first data is simultaneously processed by the inner coding / modulation units 6 and 7 of the layer 1 and the layer 2, and then combined again into the serial data in the time domain by the layer combining unit 9. Then, the combined serial data is input to the time interleaving unit 10, where the TS packets are time interleaved.

In time interleaving section 10, time interleaving length can be selected for each processing layer. Therefore, in the present embodiment, different time interleave lengths are selected in each of layer 1 and layer 2 corresponding to the first data. That is, T of the first data
The S packet is signal-processed redundantly in two routes of the layer 1 modulation / encoding / time interleaving route and the layer 2 modulation / encoding / time interleaving route. Not only have different layers (that is, different signal frequency bands), but also different time interleave lengths.

After this, signal processing is performed as in the case of the digital broadcasting system of FIG. 10, and the digital broadcasting data is transmitted through the transmission line 13 as an OFDM signal.

The OFDM signal transmitted through the transmission path 13 is received by the digital broadcast receiver 14, and the same signal processing as in the digital broadcast system of FIG. 10 is performed by the FFT section 15, pilot demodulation section 16 and frequency deinterleave section. 17 and reaches the time deinterleaver 18. Then, time deinterleaving section 18 performs time deinterleaving processing according to the time interleaving length set on the transmission side for each layer.

The signals of the respective layers deinterleaved by the time deinterleaver 18 are passed to the synthesizer 29a. The signal passed to the synthesizing unit 29a is modulation data for each carrier, and for example, for each carrier, a QPS
It is modulated by K, 16QAM, or the like. Note that the signals of the first data that have undergone transmission processing on both the layers 1 and 2 have different transmission delays when they reach the combining unit 29a. This is because different time interleave lengths are selected between layer 1 and layer 2.

Here, the composition in the composition unit 29a will be described with reference to FIG. FIG. 2 is a diagram showing a configuration example of the combining unit 29a.

As shown in FIG. 2, the signals output from the time deinterleave unit 18 are input to the input terminals 30a, 30b, 30c for each layer. Input terminal 30
The layer 1 signal input to a is input to the first delay unit 31 including a delay circuit. In addition, the signal of the layer 2 input to the input terminal 30b is the second signal formed by the delay circuit.
It is input to the delay unit 32. The first and second delay units 31,
The reference numeral 32 is provided to align the timings of the signals of the layers 1 and 2 having different transmission delays, correct the delay difference between the layers, and output them to the switch 33 and the power comparison unit 34.

The power comparison unit 34 receives the outputs of the first and second delay units 31 and 32 and calculates the reception power of each signal of layer 1 and layer 2. Then, the two values are compared, and the switch 33 having the larger received power has the output terminal 35.
The switch 33 is controlled so as to output from. More specifically, the power comparison unit 34 includes the first and second delay units 31,
Of the signals output from 32, for example, the square of the waveform amplitude of the pilot signal (that is, the power) is calculated, the two are compared, and the path switching of the switch 33 is controlled according to the comparison result. Such an operation can be easily realized by configuring the power comparison unit 34 with a circuit including, for example, a multiplication circuit, a comparator, and a logic gate such as an AND gate and an OR gate. The pilot signal, which is the reference signal for waveform equalization, is
Since it can be used as a reference signal for comparing the magnitude of received power, the power comparison unit 34 has the above-described configuration.

Of course, a signal having a large received power is less likely to be affected by noise and has an excellent receiving characteristic in a fading environment, so that it has a fading resistance among the signals of layer 1 and layer 2 corresponding to the first data. Based on the control of the power comparison unit 34, excellent and appropriate data is output to the switch 33.
Can be used for subsequent signal processing. That is, the digital broadcast receiver 14 synthesizes one piece of the first data from the received data of the layer 1 and the layer 2, and performs signal processing of the digital broadcast data.

The layer 3 input to the input terminal 30c
Is combined with the signal output from the switch 33 and output from the output terminal 35.

The signal thus synthesized is divided into substantially each layer (that is, first and second data) by the layer dividing unit 19, and the demodulation / inner code decoding units 20 to 2 are formed.
2 is demodulated and decoded (Viterbi decoding, etc.). And
Substantially each layer of data is arranged in the TS reproducing section 23 in the order of transmission, subjected to error correction processing by the Reed-Solomon code or the like in the outer code decoding section 24, and output from the output terminal 25. In this embodiment, layers 1 to 3
In demodulation / internal code decoding for each layer, since the first data and the second data are combined into two, the combined signal is processed only in two substantial layers. It

As described above, by multiplexing and transmitting predetermined data of the digital broadcast data by using two layers, a time diversity effect can be obtained between the layers, and the reception characteristic in a fading environment can be obtained. Can be improved. Also, since diversity is realized between layers, it is sufficient to provide one receiving antenna for the digital broadcast receiver, and antenna diversity cannot be applied due to the size limitation like a small portable receiver. Even in this case, the reception performance can be greatly improved. Therefore, even if strong fading or the like occurs during mobile reception using a small portable device or the like, it is possible to reduce data errors and improve mobile reception performance.

Further, by making the time interleave length different for each layer multiplexed in the time interleaving process, a time diversity effect can be further obtained between the layers, and the reception characteristic can be further improved.

Although FIG. 2 shows the case where the synthesizing unit 29a is configured by a circuit adopting the selective synthesizing method for selecting one of the same digital broadcast data assigned to the hierarchy 1 and the hierarchy 2, The combining unit 29a may be configured by a circuit that employs the equal gain combining method or the maximum ratio combining method that is often used in diversity reception.

If the circuit adopts the equal gain combining method or the maximum ratio combining method, the combining section 29a is superior in the C / N ratio characteristic, though the circuit configuration is a little complicated.
Can be realized. On the other hand, if the circuit adopts the selective combining method, a circuit having a simple structure including a determining unit (power comparing unit 34 in the present embodiment) and a switch 33 for selection is prepared as a circuit for combining. The digital broadcast receiver can be constructed at low cost.

Further, as in the present embodiment, if the respective electric powers of the same digital broadcast data assigned to a plurality of layers are calculated and the one having the larger electric power value is selected to perform the selective combination, Signals with high received power are less susceptible to noise on the transmission line and have excellent reception characteristics.
Appropriate data having excellent fading resistance can be selected from the digital broadcast data of each layer.

In the above description, the first data is the video information and the second data is the audio information. However, the types of information to be classified as the first and second data are as follows. It is not limited to such categories. For example, the first data may be assigned video and audio information of the first channel, the second data may be assigned video and audio information of the second channel, and so on.

Further, in the above description, an example in which the same digital broadcast data is transmitted by using two layers, that is, layer 1 and layer 2, has been shown. However, other three or more layers are used for the same digital broadcast data. It is also possible to transmit the digital broadcasting data of, and in this case, the effect of further improving the characteristics can be expected.

<Second Embodiment> This embodiment is a modification of the digital broadcasting system according to the first embodiment.
The selective combination performed in the digital broadcast receiver 14 is performed not based on the comparison of power values but based on the information on the degree of error calculated with the decoding of the outer code. Further, in the present embodiment, the data of the hierarchy not selected at the time of selective combining is replaced with a null packet in which invalid information is recorded.

FIG. 3 is a diagram showing a digital broadcasting system according to this embodiment. Also in FIG. 3, elements having the same functions as those of the digital broadcasting system according to the first embodiment are designated by the same reference numerals.

As shown in FIG. 3, in this digital broadcasting system, unlike the case of the digital broadcasting system according to the first embodiment, the digital broadcasting receiver 14 does not have the synthesizing unit 29a. Instead, the digital broadcast receiver 14
Includes a selection unit 36a that selects a TS packet output from the outer code decoding unit 24.

The rest of the configuration is the same as that of the digital broadcasting system according to the first embodiment, and therefore its explanation is omitted.

Next, the operation of this digital broadcasting system will be described. The operation of the digital broadcast transmitter 1 according to the present embodiment is the same as in the case of the first embodiment, and will be omitted. Also, regarding the operation of the digital broadcast receiver 14, the signal processing up to the time deinterleaving unit 18 is the same as in the case of the first embodiment, and therefore the signal processing thereafter will be described below.

The time deinterleaved signal is shown in FIG.
As in the case of the digital broadcasting system of
The demodulation / inner code decoding unit 20 to
It is demodulated and decoded at 22. Therefore, the demodulation / inner code decoding unit 20 demodulates the first data, and the demodulation / inner code decoding unit 21 demodulates the first data having a delay amount different from the output of the demodulation / inner code decoding unit 20. The second data is output from the inner code decoding unit 22.

These data are rearranged by the TS reproducing section 23 and decoded by the outer code decoding section 24. At this time, the TS reproducing unit 23 arranges the packet including the data of the layer 1, the packet including the data of the layer 2 which is the same data as the layer 1, and the packet including the data of the layer 3 so as to be temporally continuous.

The data decoded by the outer code decoder 24 is input to the selector 36a. The selecting unit 36a selects and outputs the error-free packet of the packet containing the data of the layer 1 and the packet containing the data of the layer 2 which is the same data as the layer 1.

In the outer code decoding unit 24 which performs Reed-Solomon decoding, error information indicating the degree of error as to whether or not the packet can be corrected is accompanied by the decoding of the outer code (specifically,
It is general that correctable or uncorrectable binary information) is calculated. Therefore, the error information from the outer code decoding unit 24, together with layer information indicating which layer among the layers 1 to 3 the packet currently being processed belongs to, the selection unit 3
6a, and the selection unit 36a may determine which of the tier 1 and the tier 2 should be selected.

An example of the configuration of the selection unit 36a will be described with reference to FIG. As shown in FIG. 4, among the signals output from the outer code decoding unit 24, TS packets that are digital broadcast data are input to the input terminal 37, error information is input to the input terminal 38, and hierarchy information is input to the input terminal 39. To be done.

Although FIG. 3 shows only one signal input from the outer code decoding unit 24 to the selection unit 36a, the TS packet, error information and hierarchical information of FIG. 4 are included in this one signal. It is included.

The TS packet input to the input terminal 37 is input to the third delay section 40 including a delay circuit. The third delay unit 40 is provided to align the timings of the signals of the layers 1 to 3 having different transmission delays and output the signals to one input terminal of the switch 42.

The error information input from the input terminal 38 and the hierarchical information input from the input terminal 39 are
It is input to the selection determination unit 41. The selection determination unit 41 uses the error information input from the input terminal 38 and the layer information input from the input terminal 39 to determine which of the layer 1 and layer 2 packets should be output, and switches the switch 42. Switch and select a valid packet to output.

Null packet (invalid packet) data is given to the other input end of the switch 42, and the switch 42 receives the output data of the third delay unit 40 and the output data of the third delay unit 40 under the control of the selection judging unit 41. Any of the null packet data is output from the output terminal 43.

This situation will be described with reference to FIG. Figure 5
6 is a timing chart showing the output data (selection unit input TS packet) of the third delay unit 40 and the output data (output TS packet) of the switch 42, which are input to the switch 42.

As shown in FIG. 5, under the control of the selection determination unit 41, the switch 42 determines whether one of the input TS packets belonging to the layer 1 or the layer 2 is erroneous. Outputs the packet in the layer that is not incorrect, and replaces the incorrect packet with a null packet (invalid packet).

Specifically, since the packet PK11 belonging to the layer 1 is erroneous in FIG. 5, this packet is replaced with a null packet. After that, the packet PK21 of the layer 2 and the packet PK31 of the layer 3 are sequentially output from the switch 42. Since the next packet PK12 belonging to the layer 1 is not erroneous, the packet PK22 belonging to the layer 2 is directly output from the switch 42.
Has output the packet PK12 of layer 1,
The output is no longer needed and is replaced by a null packet. After that, the same processing is performed.

The above-described processing can be easily realized by, for example, appropriately combining the selection determination unit 41 with a logic circuit such as an AND gate or an OR gate. That is, based on the combination of the content of the layer information and the content of the error information, the currently input packet is a layer 1 packet, and when it is correctable, the switch 42 outputs the packet and the subsequent layer 2 is received. The packet may be replaced with a null packet, and when it is uncorrectable, the layer 1 packet may be replaced with a null packet, and the switch 42 may output the subsequent layer 2 packet. . Since the second data is transmitted only in the layer 3, the layer 3 packet may be output regardless of an error.

In addition, without outputting a null packet, the layer 1
It is also possible to adopt a configuration in which only one of the packet of No. 2 and the packet of Layer 2 is output. However, by outputting the null packet, it is possible to match the transmission packet amount and the reception packet amount, and there is an advantage that the signal processing in the signal processing circuit after the output terminal 25 can be easily performed.

If selective combining is performed based on each error information of the same digital broadcast data assigned to layer 1 and layer 2 as in this embodiment, a signal with a small error level has excellent reception characteristics. Therefore, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

Further, as in the present embodiment, if the selective combining is performed for each packet and the data of the unselected layer of the digital broadcast data is replaced with the null packet, the data after the selective combining is performed. The packet of each layer still exists in the network, and the data amount at the time of transmission and the data amount at the time of reception can be matched. This allows
It is possible to realize a digital broadcast receiver that does not burden the signal processing after the selective combining stage.

In the above description, the example in which the same digital broadcast data is transmitted by using two layers, that is, layer 1 and layer 2, has been shown. However, the same digital broadcast data may be transmitted by using three or more layers. It is also possible to transmit the digital broadcasting data of, and in this case, the effect of further improving the characteristics can be expected.

<Third Embodiment> This embodiment is also a modification of the digital broadcasting system according to the first embodiment.
The selective combination performed in the digital broadcast receiver 14 is performed based on the transmission state of the TMCC signal, not by comparing the power values.

FIG. 6 is a diagram showing a digital broadcasting system according to this embodiment. Also in FIG. 6, elements having the same functions as those of the digital broadcasting system according to the first embodiment are designated by the same reference numerals.

As shown in FIG. 6, this digital broadcasting system includes a synthesizing unit 29b having a different configuration, instead of the synthesizing unit 29a of the digital broadcasting system according to the first embodiment. The TMCC signal SG output from the TMCC demodulation unit 27 is given to the combining unit 29b. In addition,
Since other configurations are similar to those of the digital broadcasting system according to the first embodiment, description thereof will be omitted.

Next, the operation of this digital broadcasting system will be described. The operation of the digital broadcast transmitter 1 according to the present embodiment is the same as in the case of the first embodiment, and will be omitted. Also, regarding the operation of the digital broadcast receiver 14, the signal processing up to the time deinterleaving unit 18 is the same as in the case of the first embodiment, and therefore the signal processing thereafter will be described below.

Here, the composition in the composition unit 29b will be described with reference to FIG. FIG. 7 is a diagram showing a configuration example of the combining unit 29b.

As shown in FIG. 7, the signals output from the time deinterleave unit 18 are input to the input terminals 30a, 30b, 30c for each layer. Input terminal 30
The layer 1 signal input to a is input to the first delay unit 31 including a delay circuit. In addition, the signal of the layer 2 input to the input terminal 30b is the second signal formed by the delay circuit.
It is input to the delay unit 32. The first and second delay units 31,
The reference numeral 32 is provided to correct the delay difference between the layers by aligning the timings of the signals of the layers 1 and 2 having different transmission delays, and outputting the corrected difference to the switch 33.

The synthesizing unit 29b is further provided with a first transmission state discriminating unit 45 which receives the TMCC signal input from the input terminal 44, discriminates the transmission state of the signal of each layer, and controls the switch 33. .

The first transmission state discriminating section 45 discriminates the states of the transmission paths of the layers 1 and 2 based on the TMCC signal contained in each layer. The TMCC signal is a DBPSK (Differntial Binary Pha) that is highly resistant to transmission line errors.
Since it is transmitted using the se shift keying) modulation method, it is suitable for determining the transmission path state.

In the DBPSK modulation method, 1-bit information is sent for each symbol. Therefore, by detecting the amplitude of the bit data of the TMCC signal, it is possible to determine whether or not the signal is deteriorated due to the rounded waveform or noise.

That is, the first transmission state discriminating unit 45 adopts a configuration for detecting the amplitude of the TMCC signal for each layer, and the first transmission state discriminating unit 45 discriminates the transmission state of each layer according to the amplitude. The switch 33 may be controlled by using the switch. As a specific configuration of the first transmission state determination unit 45,
A comparator that compares the amplitude of the TMCC signal with a predetermined value, and switches the path of the switch 33 based on the comparison result A
A configuration in which a logic gate such as an ND gate or an OR gate is combined may be used. When it is desired to know the influence of noise, the difference between the amplitude of the TMCC signal and a predetermined value may be used.

Of course, a signal with a large amplitude of the TMCC signal is less likely to be affected by noise and has better reception characteristics in a fading environment, so that fading of the signals of layer 1 and layer 2 corresponding to the first data is performed. Based on the control of the first transmission state determination unit 45, the switch 33 selects appropriate data having excellent endurance and outputs it to the output terminal 35.
It can be used for subsequent signal processing. Also, when estimating noise, the one with less noise is selected.

The layer 3 input to the input terminal 30c
Is combined with the signal output from the switch 33 and output from the output terminal 35.

The signal thus combined is divided into layers by the layer dividing section 19 and demodulated / decoded by the demodulation / internal code decoding sections 20 to 22 as in the case of the first embodiment. Then, the data for each layer is the TS reproduction unit 23.
Are arranged according to the order of transmission at the outer code decoding unit 24.
Then, the error correction processing is performed by the Reed-Solomon code or the like, and is output from the output terminal 25.

According to the present embodiment, selective combining is performed based on the transmission state of TMCC signals in each layer. TM
Since a signal having a good CC signal transmission state has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

In the above description, an example in which the same digital broadcast data is transmitted using two layers, layer 1 and layer 2, has been shown. However, in addition to this, three or more layers are used for the same digital broadcast data. It is also possible to transmit the digital broadcasting data of, and in this case, the effect of further improving the characteristics can be expected.

<Fourth Embodiment> This embodiment is a modification of the digital broadcasting system according to the second embodiment.
The selective combination performed in the digital broadcast receiver 14 is performed not based on the error information calculated with the decoding of the outer code, but based on the information of the degree of error calculated with the decoding of the inner code. It was done.

FIG. 8 is a diagram showing a digital broadcasting system according to this embodiment. In FIG. 8, elements having the same functions as those of the digital broadcasting system according to the second embodiment are designated by the same reference numerals.

As shown in FIG. 8, in this digital broadcasting system, unlike the case of the digital broadcasting system according to the second embodiment, the digital broadcasting receiver 14 has the selecting unit 36a after the outer code decoder 24. Instead, instead of the demodulation / inner code decoding units 20 to 22, the selection unit 36
b.

Since the other structure is the same as that of the digital broadcasting system according to the second embodiment, the description thereof will be omitted.

Next, the operation of this digital broadcasting system will be described. The operation of the digital broadcast transmitter 1 according to the present embodiment is the same as in the case of the second embodiment, and will be omitted. Also, regarding the operation of the digital broadcast receiver 14, the signal processing up to the demodulation / inner code decoding units 20 to 22 is the same as in the case of the second embodiment, and therefore the following signal processing will be described. To do.

The data of each layer output from the demodulation / inner code decoding units 20 to 22 is input to the selection unit 36b. Here, a configuration example of the selection unit 36b will be described with reference to FIG. As shown in FIG. 9, the signals output from the demodulation / inner code decoding units 20 to 22 are input terminals 48a and
It is input to 48b and 48c. The layer 1 signal input to the input terminal 48a is input to the fourth delay unit 49 including a delay circuit. In addition, the signal of the layer 2 input to the input terminal 48b receives the fifth delay unit 50 including a delay circuit.
Entered in. The fourth and fifth delay units 49 and 50 are provided to correct the delay difference between the layers by aligning the timings of the respective signals of the layer 1 and the layer 2 having different transmission delays, and outputting them to the switch 51. Has been.

The selection section 36b is further provided with a second transmission state determination section 47 which receives the Viterbi decoding information input from the input terminal 46 to determine the transmission state of the signal of each layer and controls the switch 51. ing.

The second transmission state discriminating unit 47 discriminates the states of the transmission paths of the layers 1 and 2 based on the Viterbi decoding information calculated for each layer in the demodulation / inner code decoding units 20-22.

In the demodulation / inner code decoding units 20 to 22, when performing Viterbi decoding, for example, SOVA (Soft
Output Vitabi Algorithm) and MAP (Maximum A Post)
Information on the probability of each packet, that is, information on the degree of error is generally calculated by a known algorithm such as eriori). The information on the degree of error related to Viterbi decoding is not binary information that can be corrected or impossible like error information of Reed-Solomon decoding, but is multi-valued information indicating the level of certainty in a plurality of sections. Therefore, the second transmission state determination unit 47 can determine the transmission path state using the Viterbi decoding information.

That is, it suffices that the second transmission state discriminating unit 47 discriminate the transmission state of each layer according to the value of the Viterbi decoding information for each layer and control the switch 51. As a specific configuration of the second transmission state determination unit 47, a memory that stores the values of the Viterbi decoding information of the layer 1 and the layer 2, a comparator that compares the values of the Viterbi decoding information of both layers, and a comparison result AND that switches the path of the switch 51 based on
A configuration in which a logic gate such as a gate or an OR gate is combined may be used.

Of course, a signal having a larger value of the probability of Viterbi decoding information is less likely to be affected by noise and has better reception characteristics in a fading environment, so that the layers 1 and 2 corresponding to the first data are Appropriate data having excellent fading resistance in the signal is transmitted to the second transmission state determination unit 4
The switch 51 selects the output terminal 5 based on the control of FIG.
2 and can be used for subsequent signal processing.

It should be noted that the layer 3 input to the input terminal 48c
Signal is combined with the signal output from the switch 51 and output from the output terminal 52.

As in the case of the first embodiment, the signals thus synthesized are arranged in the TS reproducing section 23 in the order of transmission, and the outer code decoding section 24 makes an error due to the Reed-Solomon code or the like. Corrected output terminal 25
Will be output.

According to the present embodiment, the selective combining is performed based on the error degree information calculated with the decoding of the inner code of each layer. Since a signal having a small degree of error has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

In the above description, the example in which the same digital broadcast data is transmitted by using the two layers of the layer 1 and the layer 2 has been shown. However, other than that, the same digital broadcast data is transmitted by using three or more layers. It is also possible to transmit the digital broadcasting data of, and in this case, the effect of further improving the characteristics can be expected.

[0123]

According to the first aspect of the invention, the digital broadcast transmitter defines a plurality of layers in the frequency domain of the signal to be transmitted, and at least two or more layers are included in the digital broadcast data. Predetermined data is multiplexed and transmitted. Then, the digital broadcast receiver receives predetermined data that is multiply assigned, synthesizes one data from the received data of each layer, and performs signal processing of the digital broadcast data. Therefore, a time diversity effect can be obtained between layers, and reception characteristics in a fading environment can be improved. Also, since diversity is realized between layers, it is sufficient to provide one receiving antenna for the digital broadcast receiver, and antenna diversity cannot be applied due to the size limitation like a small portable receiver. Even in this case, the reception performance can be greatly improved. Therefore, even if strong fading or the like occurs during mobile reception using a small portable device or the like, it is possible to reduce data errors and improve mobile reception performance.

According to the second aspect of the invention, in the time interleaving process, the time interleaving length is different for each layer of at least two or more layers. Therefore, the time diversity effect can be further obtained between the layers, and the reception characteristics can be further improved.

According to the third aspect of the invention, the combination performed in the digital broadcast receiver is selective combination, maximum ratio combination or equal gain combination. Therefore, in the case of selective combination, it is only necessary to prepare a circuit having a simple structure including a determination unit and a switch for selection as a circuit for combination, and a digital broadcast receiver can be configured at low cost. Becomes Further, in the case of the equal gain combination or the maximum ratio combination, the circuit configuration is slightly complicated, but the C / N ratio characteristic is excellent as compared with the case of the selective combination.

According to the fourth aspect of the present invention, the selective combination is performed by calculating the power of each of the predetermined data assigned in multiplex and selecting the one having the larger power value. Since a signal with high received power is not easily affected by noise on the transmission line and has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

According to the fifth aspect of the present invention, the selective combining is performed based on the information on the degree of error calculated with the decoding of the outer code of each of the predetermined data that is multiply assigned. Since a signal having a small degree of error has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

According to the invention described in claim 6, the selective combining is performed by the T of each of the predetermined data multiply assigned.
It is performed based on the transmission state of the MCC signal. Since a signal having a good TMCC signal transmission state has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

According to the seventh aspect of the present invention, the selective combining is performed based on the error degree information calculated with the decoding of each inner code of the predetermined data that is multiply assigned. Since a signal having a small degree of error has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

According to the invention described in claim 8, the selective combining is performed for each packet, and the data of the hierarchy not selected among the predetermined data assigned multiplex is replaced with the null packet. Therefore, packets of each layer still exist in the data after the selective combination, and the data amount at the time of transmission and the data amount at the time of reception can be matched.
As a result, it is possible to realize a digital broadcast receiver that does not burden the signal processing after the selective combining stage.

According to the ninth aspect of the invention, a plurality of layers are defined by dividing a predetermined frequency bandwidth into a plurality in the frequency domain of a signal to be transmitted, and at least two layers or more of the plurality of layers are defined. In addition, predetermined data included in the digital broadcast data is multiplexed and transmitted. Therefore,
A time diversity effect can be obtained between layers, and reception characteristics in a fading environment can be improved.

According to the tenth aspect of the invention, in the time interleaving processing, the time interleaving length is different for each layer of at least two layers. Therefore,
A time diversity effect can be further obtained between layers, and reception characteristics can be further improved.

According to the eleventh aspect of the present invention, predetermined data that is multiply assigned is received, one data is combined from the received data of each layer, and signal processing of digital broadcast data is performed. Therefore, a time diversity effect can be obtained between layers, and reception characteristics in a fading environment can be improved. Also, since diversity is realized between layers, it is sufficient to provide one receiving antenna for the digital broadcast receiver, and antenna diversity cannot be applied due to the size limitation like a small portable receiver. Even in this case, the reception performance can be greatly improved. Therefore, even if strong fading or the like occurs during mobile reception using a small portable device or the like, it is possible to reduce data errors and improve mobile reception performance.

According to the twelfth aspect of the invention, in the time interleaving process, the time interleaving length is different for each layer of at least two layers. Therefore,
A time diversity effect can be further obtained between layers, and reception characteristics can be further improved.

According to the thirteenth aspect of the present invention, the combining is selective combining, maximum ratio combining or equal gain combining. Therefore, in the case of selective combination, it is only necessary to prepare a circuit having a simple structure including a determination unit and a switch for selection as a circuit for combination, and a digital broadcast receiver can be configured at low cost. Becomes Further, in the case of the equal gain combination or the maximum ratio combination, the circuit configuration is slightly complicated, but the C / N ratio characteristic is excellent as compared with the case of the selective combination.

According to the fourteenth aspect of the present invention, the selective combining is performed by calculating the power of each of the predetermined data assigned in multiplex and selecting the one having the larger power value. Since a signal with high received power is not easily affected by noise on the transmission line and has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

According to the fifteenth aspect of the present invention, the selective combining is performed based on the information on the degree of error calculated with the decoding of the outer code of each of the predetermined data multiply assigned. Since a signal having a small degree of error has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

According to the sixteenth aspect of the present invention, the selective combining is performed based on the transmission state of each TMCC signal of the predetermined data that is multiply assigned. TMCC
Since a signal having a good signal transmission state has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

According to the seventeenth aspect of the present invention, the selective combining is performed based on the information about the degree of error calculated with the decoding of the respective inner codes of the predetermined data that are multiply assigned. Since a signal having a small degree of error has excellent reception characteristics, it is possible to select appropriate data having excellent fading resistance from the digital broadcast data of each layer.

According to the eighteenth aspect of the present invention, the selective combining is performed for each packet, and the data of the layer not selected among the predetermined data assigned multiplex is replaced with the null packet. Therefore, packets of each layer still exist in the data after the selective combination, and the data amount at the time of transmission and the data amount at the time of reception can be matched. As a result, it is possible to realize a digital broadcast receiver that does not burden the signal processing after the selective combining stage.

[Brief description of drawings]

FIG. 1 is a diagram showing a digital broadcasting system according to a first embodiment.

FIG. 2 is a diagram showing a configuration example of a synthesizing unit 29a in the digital broadcasting system according to the first embodiment.

FIG. 3 is a diagram showing a digital broadcasting system according to a second embodiment.

FIG. 4 is a diagram showing a configuration example of a selection unit 36a in the digital broadcasting system according to the second embodiment.

FIG. 5 is a timing chart showing an input TS packet in a selection unit 36a and an output TS packet from the selection unit 36a in the digital broadcasting system according to the second embodiment.

FIG. 6 is a diagram showing a digital broadcasting system according to a third embodiment.

FIG. 7 is a diagram showing a configuration example of a synthesizing unit 29b in the digital broadcasting system according to the third embodiment.

FIG. 8 is a diagram showing a digital broadcasting system according to a fourth embodiment.

FIG. 9 is a diagram showing a configuration example of a selection unit 36b in the digital broadcasting system according to the fourth embodiment.

FIG. 10 is a diagram showing a conventional digital broadcasting system.

FIG. 11 is a diagram illustrating time interleaving processing.

[Explanation of symbols]

1 digital broadcasting transmitter, 14 digital broadcasting receiver,
28 hierarchy selection unit, 29a, 29b synthesis unit, 36a,
36b Selector.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/21 H04N 5/38 5K059 5/38 5/60 B 5/60 7/08 Z 7/081 F Term (reference) 5C021 PA53 PA62 RB01 YA01 5C025 AA08 AA09 AA10 BA25 BA28 DA01 5C026 DA04 5C063 AA01 AB03 AB05 AC01 AC05 AC10 CA23 CA36 DA01 DA05 DA07 DA13 DB10 5K022 DD01 DD13 DD18 DD19 DD23 DD33 5K059 CC07 A07

Claims (18)

[Claims] 1. A plurality of layers are defined by dividing a predetermined frequency bandwidth in the frequency domain of a signal to be transmitted, and at least two or more layers of the plurality of layers have a predetermined number included in digital broadcast data. A digital broadcast transmitter that allocates and transmits data in a multiplexed manner, receives the predetermined data that is allocated in a multiplexed manner, synthesizes one data from the received data of each layer, and performs signal processing of the digital broadcast data. A digital broadcasting system including a digital broadcasting receiver. 2. The digital broadcasting system according to claim 1, wherein the digital broadcasting data is composed of a plurality of time-division multiplexed packets, and in the digital broadcasting transmitter, the digital broadcasting data is at least the at least the packet. Time interleave processing is performed on each of two or more layers, and in the digital broadcast receiver, the digital broadcast data is time deinterleaved on each of the at least two or more layers, In the time interleaving process, the time interleaving length, which is the amount that defines the time range of sorting when sorting adjacent data in the time order before sorting, is
A digital broadcasting system that differs for each of the at least two or more layers. 3. The digital broadcasting system according to claim 1, wherein the combining performed in the digital broadcasting receiver comprises:
A digital broadcasting system that is selective combining, maximum ratio combining, or equal gain combining. 4. The digital broadcasting system according to claim 3, wherein, in the selective combining, the power of each of the predetermined data assigned in multiplex is calculated, and one having a large power value is selected. Digital broadcasting system performed in. 5. The digital broadcasting system according to claim 3, wherein, in the digital broadcasting transmitter, an outer code for error correction is attached to the predetermined data, and in the digital broadcasting receiver, Decoding of the outer code of predetermined data is performed, and the selective combining is performed based on information about the degree of error calculated with the decoding of the outer code of each of the predetermined data that is multiply assigned. A digital broadcasting system that can be used. 6. The digital broadcasting system according to claim 3, wherein, in the digital broadcasting transmitter, the predetermined data is a signal indicating a signal format of each layer.
C (Transmission and Multiplexing Configuration Co
signal is added, the TMCC signal of the predetermined data is read by the digital broadcast receiver, and the TMCC signal of the predetermined data is read from its amplitude.
A digital broadcasting system in which a transmission state of a CC signal is determined, and the selective combining is performed based on a transmission state of the TMCC signal of each of the predetermined data assigned in multiplex. 7. The digital broadcasting system according to claim 3, wherein in the digital broadcasting transmitter, the predetermined data is internally encoded for error correction, and in the digital broadcasting receiver, Decoding of the inner code of predetermined data is performed, and the selective combining is performed based on information about the degree of error calculated with the decoding of the inner code of each of the predetermined data that is multiply assigned. A digital broadcasting system that can be used. 8. The digital broadcasting system according to claim 3, wherein the digital broadcasting data is composed of a plurality of packets that are time-division multiplexed, and the selective combining is performed for each of the packets and allocated to the multiplex. A digital broadcasting system in which unselected layer data of the predetermined data is replaced with null packets in which invalid information is recorded. 9. A plurality of layers are defined by dividing a predetermined frequency bandwidth in a frequency domain of a signal to be transmitted, and at least two or more layers of the plurality of layers are provided with a predetermined layer included in digital broadcast data. A digital broadcasting transmitter that allocates multiple data and transmits it. 10. The digital broadcast transmitter according to claim 9, wherein the digital broadcast data is composed of a plurality of time-division multiplexed packets, and the digital broadcast data includes at least two or more packets. A time interleaving process is performed for each hierarchical layer, and in the time interleaving process, a time interleaving length that is an amount that defines a time range of sorting when sorting adjacent data in a temporal order before sorting is,
A digital broadcasting transmitter that is different for each of the at least two layers. 11. A predetermined frequency bandwidth is divided in a frequency domain of a transmission signal to define a plurality of layers, and at least two or more layers of the plurality of layers include predetermined data included in digital broadcast data. Is digitally assigned, and the predetermined data that is multiply assigned is received, one data is combined from the received data of each layer, and a digital broadcast receiver that performs signal processing of the digital broadcast data is received. 12. The digital broadcast receiver according to claim 11, wherein the digital broadcast data is composed of a plurality of packets that are time-division multiplexed, and time is provided for each of the at least two or more layers. An interleave process is performed, and in the time interleave process, a time interleave length that is a quantity that defines a time range for sorting when adjacent data is sorted in a temporal order before sorting is,
A digital broadcast receiver, which is different for each of the at least two or more layers, and which performs time deinterleaving processing on the digital broadcast data for each of the at least two or more layers. 13. The digital broadcast receiver according to claim 11, wherein the combining is selective combining, maximum ratio combining or equal gain combining. 14. The digital broadcast receiver according to claim 13, wherein, in the selective combining, the power of each of the predetermined data assigned in multiplex is calculated, and the one having a large power value is selected. Digital broadcasting receivers that do this. 15. The digital broadcast receiver according to claim 13, wherein the predetermined data is provided with an outer code for error correction, and the outer code of the predetermined data is decoded. A digital broadcast receiver that performs the selective combining based on information about the degree of error calculated with the decoding of the outer code of each of the predetermined data that is multiply assigned. 16. The digital broadcast receiver according to claim 13, wherein the predetermined data is a TMCC (Transmission and Multiplexin) that is a signal indicating a signal format of each layer.
g Configuration Control) signal is added, the TMCC signal of the predetermined data is read, the transmission state of the TMCC signal is determined from the amplitude, and the selective combining is performed by the predetermined data assigned to multiplex. A digital broadcast receiver that performs the transmission based on the transmission state of each TMCC signal. 17. The digital broadcast receiver according to claim 13, wherein the predetermined data is inner-coded for error correction, and the inner code of the predetermined data is decoded. A digital broadcast receiver that performs the selective combining based on information about the degree of error calculated with the decoding of the inner code of each of the predetermined data that is multiply assigned. 18. The digital broadcast receiver according to claim 13, wherein the digital broadcast data is composed of a plurality of time-division multiplexed packets, and the selective combining is performed for each of the packets. A digital broadcast receiver that replaces data of a layer that is not selected among the predetermined data assigned to a null packet in which invalid information is recorded.