JP7261996B2 - Broadcast receiving method and broadcast receiving device - Google Patents

Description

The present disclosure relates to a broadcast receiving method and a broadcast receiving apparatus.

In satellite broadcasting, practical broadcasting (so-called 4K/8K practical broadcasting) that utilizes ultra-high-definition video technology has started, and terrestrial broadcasting is similarly being studied for sophistication. As one of technical methods used in such advanced terrestrial broadcasting, an LDM (Layered Division Multiplexing) method is under study (see, for example, Patent Document 1). In the LDM system, for example, the current ISDB-T (Integrated Services Digital Broadcasting for Terrestrial Television Broadcasting) system digital terrestrial broadcasting signal (hereinafter also referred to as "2K broadcasting signal"), and the next generation 4K broadcasting signal , are hierarchically division-multiplexed in the same frequency band as a high-power layer and a low-power layer, respectively. By using the LDM system, existing receivers can receive current 2K broadcasts, and new receivers compatible with 4K broadcasts can selectively view 2K broadcasts and 4K broadcasts.

Japanese Patent Application Publication No. 2018-503997

When a broadcast signal using the LDM method (hereinafter also referred to as "LDM signal") is received by a new receiver compatible with 4K broadcast, the 2K broadcast included in the LDM signal is received and the 2K broadcast signal is removed from the LDM signal. 4K broadcast signals can be acquired by doing so. Here, when the signal-to-noise ratio (in other words, carrier-to-noise ratio) of the received 4K broadcast signal is equal to or higher than a predetermined threshold, 4K broadcast can be received. Thus, in order to determine whether 4K broadcasting can be received, it is necessary to once decode the 4K broadcasting signal. In other words, even if 4K broadcasting cannot be received, it is necessary to operate a circuit for decoding 4K broadcasting signals. As a result, power consumption in the receiver is greatly increased compared to existing receivers.

Therefore, the present disclosure provides a broadcast receiving method and a broadcast receiving apparatus that can determine whether or not to receive broadcasts included in the low-power layer of an LDM signal while suppressing power consumption.

A broadcast reception method according to an aspect of the present disclosure is such that the first digital broadcast signal modulated by the first modulation scheme and the second digital broadcast signal modulated by the second modulation scheme are in the high-power hierarchy and the low-power hierarchy, respectively. A broadcast reception method in which a broadcast receiving device receives a digital broadcast signal transmitted by hierarchical division multiplexing in the LDM system as a broadcast reception method, wherein the first digital broadcast signal is received, and the first digital broadcast signal is converted to the second an extracting step of extracting transmission information announcing the transmission of a digital broadcasting signal; an acquiring step of acquiring a signal-to-noise ratio of said first digital broadcasting signal; and said high power layer and said low power included in said transmission information. a determination step of determining whether or not the second digital broadcast signal can be received based on injection level information indicating a ratio of the signal level to the hierarchy and the signal-to-noise ratio of the first digital broadcast signal; including.

In addition, these general or specific aspects may be realized by a system, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM. Any combination of media may be implemented.

The broadcast receiving method and broadcast receiving apparatus according to the present disclosure can determine whether or not to receive broadcasts included in the low-power layer of the LDM signal while suppressing power consumption.

FIG. 1 is a block diagram showing functional configurations of a broadcast receiving apparatus and a television receiver according to an embodiment. FIG. 2 is a graph showing the relationship between the signal level and frequency of the first digital broadcast signal and the second digital broadcast signal according to the embodiment. FIG. 3 is a table showing an example of allocation of injection level information to undefined bits according to the embodiment. FIG. 4 is a flow chart showing an example of a broadcast reception method according to the embodiment. FIG. 5 is a flowchart showing an example of a broadcast reception method according to Modification 1 of the embodiment.

Hereinafter, embodiments will be specifically described with reference to the drawings.

It should be noted that the embodiments described below are all comprehensive or specific examples. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are examples, and are not intended to limit the present disclosure. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in independent claims representing the highest concept will be described as arbitrary constituent elements.

Each figure is a schematic diagram and is not necessarily strictly illustrated. Moreover, in each figure, the same code|symbol is attached|subjected about the same component.

(Embodiment)
[composition]
First, configurations of a broadcast receiving apparatus and a television receiver according to Embodiment 1 will be described with reference to the drawings. FIG. 1 is a block diagram showing functional configurations of a broadcast receiving apparatus 12 and a television receiver 10 according to this embodiment.

The television receiver 10 is a device that receives a broadcast signal and displays an image corresponding to the broadcast signal. The television receiver 10 includes, as shown in FIG. The video display unit 62 is, for example, a display panel such as a liquid crystal display panel or an organic EL display panel. In the present embodiment, television receiver 10 further includes audio output section 60 that outputs audio corresponding to the audio signal output from broadcast receiving apparatus 12 . The audio output unit 60 is, for example, a speaker. The audio output unit 60 may include an amplifier that amplifies the audio signal.

The broadcast receiver 12 classifies the first digital broadcast signal modulated by the first modulation scheme and the second digital broadcast signal modulated by the second modulation scheme as a high-power hierarchy and a low-power hierarchy, respectively, in the LDM system. This is a device for receiving digital broadcasting signals that are division-multiplexed and transmitted. The first digital broadcast signal and the second digital broadcast signal are not particularly limited. The first digital broadcasting signal is, for example, the current ISDB-T terrestrial digital broadcasting signal (hereinafter also referred to as "2K broadcasting signal"). The second digital broadcast signal is, for example, a next-generation television broadcast signal with ultra-high-definition image quality called 4K (hereinafter also referred to as "4K broadcast signal"). The first modulation scheme, which is the modulation scheme of the first digital broadcast signal, and the second modulation scheme, which is the modulation scheme of the second digital broadcast signal, are not particularly limited. For example, 64QAM (3/4) and 1024QAM (11/16) can be used as the first modulation method and the second modulation method, respectively (the coding rate is in parentheses).

The first digital broadcast signal and the second digital broadcast signal will be explained using FIG. FIG. 2 is a graph showing the relationship between the signal level and frequency of the first digital broadcast signal and the second digital broadcast signal according to this embodiment. FIG. 2 shows the tuner output power as the received signal levels of the first digital broadcast signal and the second digital broadcast signal. Here, the tuner output power means the power of each signal included in the output signal of the tuner section 20 shown in FIG. The high power hierarchy (UL) shown in FIG. 2 indicates the signal level of the first digital broadcasting signal (tuner output power C _UL ), and the low power hierarchy (LL) indicates the signal level of the second digital broadcasting signal (tuner output power C _LL ). As shown in FIG. 2, the frequency bands of the first digital broadcast signal and the second digital broadcast signal are the same.

The broadcast receiver 12 includes an extractor and a controller 58 . In this embodiment, the multiplexed signal separator 52 shown in FIG. 1 functions as an extractor. The broadcast receiving device 12 further includes a tuner section 20, a demodulation circuit 22, a first decoding section 14, a second decoding section 16, a selector 50, a video/audio decoding section 54, and a video synthesis section 56. .

The tuner unit 20 is a circuit that receives a broadcast signal that is an RF signal, selects a partial frequency band included in the broadcast signal, and performs processing such as frequency conversion on the broadcast signal in that frequency band. . The frequency band selected by the tuner unit 20 corresponds to, for example, a channel selected by the user. The tuner unit 20 converts the broadcast signal of the selected frequency band into a baseband signal at the center frequency of the frequency band. Tuner section 20 may further adjust the strength of the output signal.

The demodulation circuit 22 is a circuit that performs OFDM (Orthogonal Frequency Division Multiplex) demodulation processing on the baseband signal output from the tuner section 20 . The demodulation circuit 22 outputs a signal corresponding to the data mapped on the IQ coordinates.

The first decoding unit 14 is a circuit unit that decodes the first digital broadcast signal. The first decoding unit 14 has a demapping circuit 24, a deinterleaving circuit 26, and an error correction decoding circuit 28, as shown in FIG.

The demapping circuit 24 is a circuit that performs demapping of the data mapped to the IQ coordinates included in the signal output from the demodulation circuit 22 and outputs a signal corresponding to bit data. In this embodiment, the demapping circuit 24 demaps data corresponding to the high power hierarchy of the LDM signal. That is, the demapping circuit 24 demaps data corresponding to the first digital broadcast signal. The demapping circuit 24 also obtains information corresponding to the tuner output power _CUL of the high power hierarchy of the LDM signal. Further, the demapping circuit 24 calculates a signal-to-noise ratio (in other words, carrier-to-noise ratio) C _UL /N represented by the following equation (1) using a plurality of data mapped to the IQ coordinates. .

_CUL /N= _CUL /(KTBF) (1)

where N, K, T, B and F represent tuner output noise, Boltzmann's constant (1.38×10 ⁻²³ ), absolute temperature, signal bandwidth and tuner noise figure, respectively. The tuner output noise N is thermal noise included in the output of the tuner section 20, and the tuner noise factor F is the ratio of the input signal-to-noise ratio of the tuner section 20 to the output signal-to-noise ratio. The absolute temperature T is set to 300 [K] at 27° C., for example. The demapping circuit 24 outputs the calculated signal-to-noise ratio C _UL /N to the controller 58 . The signal-to-noise ratio C _UL /N may be acquired by another circuit of the broadcast receiving device 12 and output to the control section 58 .

The deinterleave circuit 26 is a circuit that restores the order of bit data rearranged based on a predetermined rule on the transmission side of the broadcast signal to the original order. The de-interleave circuit 26 restores the order of the bit data rearranged based on the ISDB-T standard, for example, to the original order.

The error correction decoding circuit 28 is a circuit that performs error correction decoding processing on bit data included in the signal output from the deinterleaving circuit 26 . For example, a Reed-Solomon code or the like can be used as the error correction code. Thereby, bit data corresponding to the first digital broadcast signal can be acquired. A signal including bit data corresponding to the first digital broadcast signal output from the error correction decoding circuit 28 is input to the selector 50 and the error correction encoding circuit 38 of the second decoding section 16 .

The second decoding unit 16 is a circuit unit that decodes the second digital broadcast signal. As shown in FIG. 1, the second decoding unit 16 includes a delay circuit 40, a subtractor 30, a multiplier 32, a mapping circuit 34, an interleaving circuit 36, an error correction coding circuit 38, and a demapping circuit. It has a circuit 44 , a deinterleaving circuit 46 and an error correction decoding circuit 48 .

The error correction coding circuit 38 is a circuit that performs error correction coding processing on bit data corresponding to the first digital broadcast signal output from the error correction decoding circuit 28 . For example, a Reed-Solomon code or the like can be used as the error correction code.

The interleaving circuit 36 is a circuit that rearranges the error-correction-encoded bit data included in the signal output from the error-correction encoding circuit 38 based on the same rules as those on the transmission side of the broadcast signal. The interleaving circuit 36 rearranges the bit data based on the ISDB-T standard, for example.

The mapping circuit 34 is a circuit that maps the bit data included in the signal output from the interleaving circuit 36 to IQ coordinates. Mapping circuit 34 outputs the mapped data to multiplier 32 .

The multiplier 32 is a circuit that multiplies the signal output from the mapping circuit 34 and the power ratio. The power ratio is the ratio of the power of the signal corresponding to the first digital broadcast signal output by the delay circuit 40 to the power of the signal output by the mapping circuit 34 . Thereby, the multiplier 32 can output a signal having power equal to the power of the signal corresponding to the first digital broadcast signal output by the delay circuit 40 .

The delay circuit 40 is a circuit that delays the timing at which the signal output from the demodulation circuit 22 is input to the subtractor 30 . The delay circuit 40 receives the signal output from the demodulation circuit 22, delays the signal by a predetermined delay time, and outputs the signal. The delay circuit 40 delays the timing at which the signal output from the demodulation circuit 22 is input to the subtractor 30 without passing through the demapping circuit 24 or the like. 28, a circuit for synchronizing with the timing input to the subtractor 30 via the error correction coding circuit 38, the interleave circuit 36, the mapping circuit 34 and the multiplier 32; The delay time of the signal in the delay circuit 40 is determined by the signal passing through the demapping circuit 24, the deinterleaving circuit 26, the error correction decoding circuit 28, the error correction coding circuit 38, the interleaving circuit 36, the mapping circuit 34 and the multiplier 32. equal to the time required for

The subtractor 30 is a circuit that subtracts the signal output by the multiplier 32 from the signal output by the delay circuit 40 . Thereby, the signal corresponding to the first digital broadcasting signal can be removed from the signals corresponding to the first digital broadcasting signal and the second digital broadcasting signal included in the signal output from the delay circuit 40 .

The demapping circuit 44 is a circuit that performs demapping of the data mapped to the IQ coordinates included in the signal output from the subtractor 30 and outputs a signal corresponding to bit data. In this embodiment, the demapping circuit 44 demaps the data corresponding to the low power hierarchy of the LDM signal. That is, the demapping circuit 44 demaps data corresponding to the second digital broadcast signal.

The deinterleave circuit 46 is a circuit that restores the order of bit data rearranged based on a predetermined rule on the transmission side of the broadcast signal to the original order. The deinterleave circuit 46 restores the order of the bit data rearranged by the broadcasting station to the original order, for example.

The error correction decoding circuit 48 is a circuit that performs error correction decoding processing on bit data included in the signal output from the deinterleaving circuit 46 . For example, a BCH code or the like can be used as the error correction code. Thereby, bit data corresponding to the second digital broadcast signal can be obtained. A signal containing bit data corresponding to the second digital broadcast signal output from the error correction decoding circuit 48 is input to the selector 50 .

A selector 50 is a circuit that selectively outputs one of the signals output from the error correction decoding circuits 28 and 48 . That is, the selector 50 selectively outputs one of the first digital broadcast signal and the second digital broadcast signal. The selector 50 may, for example, select a signal according to an instruction from the user.

The multiplexed signal separation unit 52 is a processing unit that separates multiplexed data. The multiplexed signal separator 52 separates the decoded data into program data, control data, etc., and extracts an encoded video signal and an encoded audio signal from the program data. The encoded video signal and encoded audio signal separated by the multiplexed signal separation unit 52 are output to the video/audio decoding unit 54 . Also, the multiplexed signal separation unit 52 is an example of an extraction unit that receives the first digital broadcast signal and extracts transmission information for notifying transmission of the second digital broadcast signal from the first digital broadcast signal. The multiplexed signal separation section 52 outputs a signal corresponding to the extracted transmission information to the control section 58 .

The video/audio decoding unit 54 is a processing unit that decodes the encoded video signal and the encoded audio signal, respectively. A video signal obtained by decoding the encoded video signal is output to the video synthesizing unit 56 , and an audio signal obtained by decoding the encoded audio signal is output to the outside of the broadcast receiving apparatus 12 . In this embodiment, the audio signal is output to the audio output section 60 of the television receiver 10 .

The video synthesizing unit 56 is a processing unit that synthesizes the video signal output from the video/audio decoding unit 54 and the video signal indicating the notification information output from the control unit 58 to generate a new video signal. . Notification information will be described later.

The control unit 58 extracts the injection level information indicating the signal level ratio between the high-power hierarchy and the low-power hierarchy in the LDM system, and the signal-to-noise ratio of the first digital broadcast signal, which are included in the transmission information extracted by the extraction unit. , and determines whether or not the second digital broadcast signal can be received. Details of control in the control unit 58 will be described later.

[Broadcast reception method]
Next, a broadcast receiving method in broadcast receiving apparatus 12 according to this embodiment will be described.

In the broadcast reception method according to the present embodiment, whether or not the second digital broadcast signal can be received is determined only by decoding the first digital broadcast signal without decoding the second digital broadcast signal. For this reason, in the present embodiment, transmission information for notifying transmission of the second digital broadcast signal is added to the first digital broadcast signal. The transmission information includes injection level information that indicates the signal level ratio (that is, power ratio) between the high-power layer and the low-power layer in the LDM signal. Here, the signal levels of the high power hierarchy and the low power hierarchy are set by the broadcasting station. The receivable area (that is, service area) of the first digital broadcast signal and the second digital broadcast signal changes according to the injection level information.

In the present embodiment, broadcast receiving apparatus 12 adds transmission information to the first digital broadcast signal so that transmission information can be obtained when receiving the first digital broadcast signal. The mode of adding the transmission information to the first digital broadcast signal is not particularly limited. For example, injection level information may be assigned to undefined bits of a TMCC (Transmission and Multiplexing Configuration Control) signal of the first digital broadcast signal. A TMCC signal is a signal containing transmission information such as a modulation scheme. Allocation of injection level information to undefined bits will be described with reference to FIG. FIG. 3 is a table showing an example of allocation of injection level information to undefined bits according to this embodiment.

As shown in FIG. 3, for example, the injection level information ( A signal level ratio 10 log(C _UL /C _LL )) may be assigned. Thereby, the broadcast receiver 12 can extract the injection level information included in the TMCC signal as the transmission information. In other words, the broadcast receiver 12 determines that the transmission of the second digital broadcast signal has been notified by the fact that the injection level information is included in the TMCC signal. Further, the broadcast receiver 12 can acquire information indicating the numerical range of the signal level ratio from the injection level information.

An example of a broadcast reception method using such transmission information will be described with reference to FIG. FIG. 4 is a flow chart showing an example of a broadcast reception method according to this embodiment.

As shown in FIG. 4, the broadcast receiver 12 first receives the TMCC signal included in the first digital broadcast signal (S12). Specifically, the multiplexed signal separator 52 separates the TMCC signal from the bit data included in the first digital broadcast signal decoded by the first decoder 14 of the broadcast receiver 12 .

Next, the demultiplexing unit 52 determines whether or not the TMCC signal contains transmission information (S14). In this embodiment, the multiplexed signal separator 52 checks the undefined bits of the TMCC signal and determines whether injection level information is included as transmission information. When the demultiplexing unit 52 determines that the TMCC signal does not contain the transmission information (No in S14), it ends the operation of determining whether or not the second digital broadcast signal can be received. When the demultiplexing unit 52 determines that the transmission information is included in the TMCC signal (Yes in S14), it extracts the transmission information from the TMCC signal (S16). In this embodiment, the multiplexed signal separation unit 52 extracts injection level information indicating the signal level ratio between the high power hierarchy and the low power hierarchy included in the transmission information. The multiplexed signal separator 52 outputs the extracted injection level information to the controller 58 .

Next, the control unit 58 acquires the signal-to-noise ratio (C _UL /N) of the first digital broadcast signal (S18). In the present embodiment, the signal-to-noise ratio of the first digital broadcast signal is calculated using the above equation (1) in demapping circuit 24 and output to control section 58 .

Next, the control unit 58 determines whether or not the second digital broadcast signal can be received (S20). In the present embodiment, the control unit 58 uses the following equation (2) from the signal-to-noise ratio ( _CUL /N) of the first digital broadcast signal and the injection level information (ILR= _CUL / _CLL ): is used to calculate the signal-to-noise ratio (C _LL /N) of the second digital broadcast signal.

_CLL /N= _CUL /(N×ILR)
= ( _CUL /N) x 1/ILR (2)

When the signal-to-noise ratio (C _LL /N) of the second digital broadcast signal calculated using the above formula (1) is equal to or greater than a predetermined threshold, the control unit 58 determines that the second digital broadcast signal can be received. judge. On the other hand, when the signal-to-noise ratio (C _LL /N) is less than a predetermined threshold, it is determined that the second digital broadcast signal cannot be received. Thus, the control unit 58 can calculate the signal-to-noise ratio (C _LL /N) of the second digital broadcast signal without actually decoding the second digital broadcast signal in the broadcast receiver 12 . Therefore, the broadcast receiver 12 can determine whether or not the second digital broadcast signal can be received without operating the second decoding section 16 . Therefore, in the broadcast receiving device 12, the control unit 58 determines that the second digital broadcast signal can be received, and only when the user or the like instructs to receive the second digital broadcast signal, the second decoding unit 16 is activated. Therefore, since the power required to decode the second digital broadcast signal, that is, the power required to operate the second decoding unit 16 can be minimized, the power consumption of the broadcast receiving device 12 can be suppressed.

Note that the signal-to-noise ratio (C _UL /N) of the first digital broadcast signal varies depending on weather conditions and the like. Therefore, measuring the signal-to-noise ratio (C _UL /N) over a long period of time may improve the measurement accuracy. Also, the signal-to-noise ratio (C _UL /N) can be measured while receiving the first digital broadcast signal (that is, while watching the first digital broadcast). Therefore, by continuing to measure the signal-to-noise ratio (C _UL /N), it is possible to constantly determine whether reception is possible. As a result, even when the service area of the second digital broadcast gradually expands, the second digital broadcast can be viewed without delay as soon as the second digital broadcast signal becomes receivable.

Also, in the LDM system, a method of gradually increasing the power of the second digital broadcasting signal and gradually decreasing the power of the first digital broadcasting signal to expand the service area of the second digital broadcasting is also conceivable. In that case, the injection level information included in the TMCC signal changes. Even in this case, it is possible to determine whether or not the second digital broadcast signal can be received based on the signal-to-noise ratio of the first digital broadcast signal and the injection level information.

When the control unit 58 determines that the second digital broadcast signal can be received (Yes at S20), the broadcast receiver 12 acquires the channel from the second digital broadcast signal (S22). In other words, the broadcast receiver 12 scans the channels of the second digital broadcast signal and acquires the channels included in the second digital broadcast signal. It should be noted that in step S22, channel scanning does not necessarily have to be forcibly performed. For example, the control unit 58 of the broadcast receiving device 12 causes the image display unit 62 to display an image showing a message asking whether scanning of channels is permitted, and the user permits scanning in response to the message. A scan may be performed only if Also, if the user does not allow scanning, the scanning may be canceled. As described above, according to the broadcast reception method according to the present embodiment, the channel setting can be updated without delay when the reception of the second digital broadcast signal becomes possible.

On the other hand, when the control unit 58 determines that the second digital broadcast signal cannot be received (No in S20), the control unit 58 notifies that the second digital broadcast signal cannot be received (S24). In this embodiment, the control unit 58 notifies that the second digital broadcast signal is being transmitted and that the broadcast receiver 12 cannot receive the signal. The mode of notification is not particularly limited. In this embodiment, control unit 58 outputs a video signal including notification information. Here, the notification information includes information indicating that the second digital broadcast signal is being transmitted and that the broadcast receiver 12 cannot receive the signal. The video synthesizing unit 56 synthesizes the video signal output from the video/audio decoding unit 54 and the video signal output from the control unit 58 , and outputs the synthesized video signal to the video display unit 62 . As a result, the image display unit 62 of the television receiver 10 displays the notification image indicating the notification information. As the notification image, for example, an image such as a character string indicating notification information can be used. As the character string, for example, a character string such as "The second digital broadcast signal is being sent, but cannot be received because the signal level is low." can be used.

As described above, according to the broadcast reception method according to the present embodiment, it is possible to determine whether or not the second digital broadcast can be received while suppressing power consumption.

[Broadcast Reception Method According to Modification 1]
Next, a broadcast reception method according to Modification 1 of the present embodiment will be described. Although the example in which the transmission information is included in the TMCC signal has been described in the above embodiments, the transmission information may be included in other signals. For example, the sending information may be included in an SDTT (Software Download Trigger Table) signal. The SDTT signal is a signal for notifying download of software used in a broadcast receiver, and is added to all broadcast signals irregularly. The SDTT signal contains information such as the version number of the download content, the transmission channel, and the transmission time zone.

For example, transmission information may be assigned to undefined bits of the SDTT signal. More specifically, among the bits of reserved_future_use, which is the user area of the SDTT signal specified in the technical document ARIB-TR-B14 of the Association of Radio Industries and Businesses, for example, the lower 6 bits have an injection level as shown in FIG. information may be assigned. As a result, transmission information can be added without affecting the first digital broadcast signal.

Hereinafter, as a broadcast receiving method according to this modified example, a broadcast receiving method in the case where the SDTT signal includes transmission information will be described with reference to FIG. FIG. 5 is a flowchart showing an example of a broadcast reception method according to this modification.

As shown in FIG. 5, the broadcast receiver 12 first receives the first digital broadcast signal and determines whether or not the SDTT signal has been received (S42). The multiplexed signal separator 52 determines whether the bit data included in the first digital broadcast signal decoded by the first decoder 14 of the broadcast receiver 12 includes an SDTT signal.

When the demultiplexing unit 52 determines that the SDTT signal is not included in the bit data (No in S42), it ends the operation of determining whether the second digital broadcast signal can be received. When the demultiplexing unit 52 determines that the SDTT signal is included in the bit data (Yes in S42), it determines whether or not the SDTT signal includes transmission information (S44). In this modification, the multiplexed signal separation unit 52 determines whether injection level information is included as transmission information in the reserved_future_use bit of the SDTT signal.

When the demultiplexing unit 52 determines that the SDTT signal does not contain transmission information (No in S44), it determines whether scanning of the first digital broadcast signal is necessary (S46). Scanning of the first digital broadcast signal is performed according to ARIB-TR-B14, for example, when the version of the download content is updated and the frequency list is changed. When the demultiplexing unit 52 determines that scanning of the first digital broadcast signal is unnecessary (No in S46), it ends the operation of determining whether or not the second digital broadcast signal can be received. On the other hand, when the demultiplexing unit 52 determines that the scanning of the first digital broadcast signal is necessary (Yes in S46), it acquires the channel from the first digital broadcast signal (S48). That is, the broadcast receiver 12 scans the channels of the first digital broadcast signal to acquire the channels included in the first digital broadcast signal.

When the demultiplexing unit 52 determines that the SDTT signal contains transmission information (Yes in S44), it extracts the transmission information from the SDTT signal (S50). In this embodiment, the multiplexed signal separation unit 52 extracts injection level information indicating the signal level ratio between the high power hierarchy and the low power hierarchy included in the transmission information. The multiplexed signal separator 52 outputs the extracted injection level information to the controller 58 .

Next, the control unit 58 acquires the signal-to-noise ratio (C _UL /N) of the first digital broadcast signal (S18), as in step S18 (see FIG. 4) of the above embodiment.

Thereafter, also in the broadcast receiving method according to this modification, steps similar to steps S20, S22, and S24 according to the above-described embodiment are executed.

As described above, in the broadcast reception method according to this modification, it is possible to determine whether or not the second digital broadcast can be received while suppressing power consumption, as in the broadcast reception method according to the above-described embodiment.

[Broadcast Reception Method According to Modification 2]
Next, a broadcast reception method according to Modification 2 of the present embodiment will be described. In the above embodiment, the signal-to-noise ratio (C _UL /N) of the first digital broadcast signal was calculated using the above formula (1), but the method for obtaining the signal-to-noise ratio (C _UL /N) is It is not limited to this. For example, the signal-to-noise ratio (C _UL /N) of the first digital broadcast signal may be calculated based on information on the location where the broadcast receiver 12 is installed. An example of a broadcast reception method for acquiring the signal-to-noise ratio (C _UL /N) of the first digital broadcast signal based on information on the location where the broadcast receiver 12 is installed will be described below.

In this modification, the first digital broadcast signal includes, as transmission information, the broadcast station output power P, which is the output power of the broadcast signal at the broadcast station. As a result, the multiplexed signal separation unit 52 of the broadcast receiving apparatus 12 can extract the broadcast station output power P as transmission information in the same manner as in the above broadcast receiving methods.

Generally, in the broadcast receiver 12, a user or the like inputs information indicating the position where the broadcast receiver 12 is installed (that is, the current position) in order to acquire a channel. For example, the zip code of the location where the broadcast receiving device 12 is installed is input. Based on such information, it is possible to acquire information on the position where the broadcast receiving device 12 is installed and information on the position of the broadcasting station that transmits the broadcast signal to that position (installation position of the antenna for transmitting the broadcast signal). For example, the control unit 58 may store a table showing the correspondence between postal codes and installation positions of broadcast signal transmitting antennas. Based on this table, it is possible to obtain information on the installation position of the broadcast signal transmitting antenna from the input postal code. Based on this information, the broadcast receiver 12 can calculate the distance from the broadcast station to the broadcast receiver 12 and the free space loss Lf calculated from the distance.

Here, using the gain G of a general broadcast signal receiving antenna, the above-mentioned injection level information (ILR= _CUL / _CLL ), the broadcasting station output power P, and the free space loss Lf, the first digital broadcast signal The signal level _{CUL of} is represented by the following equation (3).

_CUL = (1+1/ILR)/(PG/Lf) (3)

Therefore, the signal-to-noise ratio ( _CUL /N) of the first digital broadcast signal is represented by the following equation (4).

_CUL /N=(1+1/ILR)/(PGN/Lf)
=(1+1/ILR)/(PGKTBF/Lf) (4)

As described above, in the step (S18) of acquiring the signal-to-noise ratio ( _CUL /N) of the first digital broadcast signal of each broadcast reception method, location information indicating the current location of the broadcast reception device is acquired, A signal-to-noise ratio ( _CUL /N) of the first digital broadcast signal may be calculated. According to such a method, the signal-to-noise ratio of the first digital broadcast signal can be acquired without measuring the signal level of the first digital broadcast signal in the broadcast receiver 12 . Also, in this modified example, the same effect as that of each of the broadcast reception methods described above can be obtained.

[summary]
As described above, in the broadcast reception method according to the present embodiment, the first digital broadcast signal modulated by the first modulation scheme and the second digital broadcast signal modulated by the second modulation scheme are and a broadcast reception method in which a broadcast receiver receives a digital broadcast signal that is hierarchically division-multiplexed and transmitted in the LDM system as a low-power hierarchy. A broadcast reception method includes an extracting step of receiving a first digital broadcast signal and extracting transmission information for notifying transmission of a second digital broadcast signal from the first digital broadcast signal; and an obtaining step of obtaining. The broadcast reception method further comprises injection level information indicating a signal level ratio between the high-power hierarchy and the low-power hierarchy, and the signal-to-noise ratio of the first digital broadcast signal, which are included in the transmission information. and a determining step of determining whether or not the secondary digital broadcasting signal can be received.

This makes it possible to determine whether or not the second digital broadcast signal can be received without decoding the second digital broadcast signal, that is, without operating the second decoding unit 16 of the broadcast receiver 12 . Therefore, the broadcast receiver 12 can decode the second digital broadcast signal only when it is determined that the second digital broadcast signal is receivable and when there is an instruction to receive the second digital broadcast signal from the user or the like. Just do it. Therefore, since the power required to decode the second digital broadcast signal, that is, the power required to operate the second decoding unit 16 can be minimized, the power consumption of the broadcast receiving device 12 can be suppressed.

Moreover, in the broadcast reception method according to the present embodiment, the first digital broadcast signal may include a TMCC signal, and the transmission information may be included in the TMCC signal.

Since the TMCC signal includes undefined bits as described above, by allocating the transmission information to the undefined bits, the transmission information can be added without affecting the first digital broadcast signal.

Moreover, in the broadcast receiving method according to the present embodiment, the first digital broadcast signal may include an SDTT signal, and the transmission information may be included in the SDTT signal.

Since the SDTT signal includes undefined bits as described above, by allocating transmission information to the undefined bits, the transmission information can be added without affecting the first digital broadcast signal.

Moreover, the broadcast reception method according to the present embodiment may further include a notification step of notifying that reception is impossible when it is determined that reception is impossible in the determination step.

This makes it possible to inform the user that although the second digital broadcast signal is being transmitted, it cannot be received due to the low signal level.

Further, in the broadcast receiving method according to the present embodiment, in the acquiring step, position information indicating the current position of the broadcast receiving device 12 is acquired, and the signal-to-noise ratio of the first digital broadcast signal is calculated based on the position information. You may

As a result, the signal-to-noise ratio of the first digital broadcast signal can be obtained without measuring the signal level of the first digital broadcast signal in the broadcast receiver 12 .

Further, the broadcast receiving apparatus 12 according to the present embodiment is configured such that the first digital broadcast signal modulated by the first modulation method and the second digital broadcast signal modulated by the second modulation method are hierarchically division-multiplexed by the LDM method. It is a device that receives a digital broadcast signal that is transmitted after being transmitted. The broadcast receiving device 12 receives the first digital broadcast signal, extracts the transmission information for notifying the transmission of the second digital broadcast signal from the first digital broadcast signal, Control for determining whether or not the second digital broadcast signal can be received based on the injection level information indicating the signal level ratio between the power hierarchy and the low power hierarchy and the signal-to-noise ratio of the first digital broadcast signal and

As a result, the same effects as those of the above-described broadcast receiving method can be obtained.

(Modified example, etc.)
As described above, the broadcast reception method and the like of the present disclosure have been described based on the embodiment and the modification thereof, but the present disclosure is not limited to the above-described embodiment and the modification thereof. As long as they do not deviate from the spirit of the present disclosure, various modifications conceived by a person skilled in the art may be included in the scope of the present disclosure as well as the above-described embodiments and modifications thereof.

For example, in the above-described embodiment, the broadcast receiving device 12 is provided in the television receiver 10, but the broadcast receiving device 12 may be used alone, or may be used in a recording device, a set-top box, or the like. It may be provided in other devices.

Also, although two broadcast signals, the first digital broadcast signal and the second digital broadcast signal, are used in the LDM system, two or more broadcast signals may be used in the LDM system. For example, in the LDM system, three broadcast signals, namely, a 2K broadcast signal, a 4K broadcast signal and an 8K broadcast signal may be used in order from the high power side.

Also, the LDM method may not be applied to the entire first digital broadcast signal and the second digital broadcast signal, and may be applied to at least a part of them. For example, the LDM scheme may be applied only to some segments of the frequency band of each broadcast signal.

Further, in the above-described embodiment, an example is shown in which a video signal is output to the video synthesizing unit 56 in order to notify that the second digital broadcast signal cannot be received by the broadcast receiving device 12. The mode of notifying that the broadcast signal cannot be received is not limited to this. For example, the broadcast receiver 12 may output an audio signal.

Further, each step of the broadcast reception method according to the above embodiments and modifications thereof may be executed by a computer (computer system). The present disclosure can be realized as a program for causing a computer to execute the steps included in those methods. Furthermore, the present disclosure can be implemented as a non-temporary computer-readable recording medium such as a CD-ROM recording the program.

For example, when the present disclosure is implemented by a program (software), each step is executed by executing the program using hardware resources such as the CPU, memory, and input/output circuits of the computer. . In other words, each step is executed by the CPU acquiring data from a memory, an input/output circuit, or the like, performing an operation, or outputting the operation result to the memory, an input/output circuit, or the like.

Moreover, each of the plurality of components included in the broadcast receiving apparatus 12 of the above-described embodiment may be implemented as a dedicated or general-purpose circuit. These components may be implemented as one circuit or as multiple circuits.

Moreover, the plurality of components included in the broadcast receiving apparatus 12 of the above-described embodiment may be implemented as an LSI (Large Scale Integration), which is an integrated circuit (IC: Integrated Circuit). These components may be made into one chip individually, or may be made into one chip so as to include some or all of them. LSIs are sometimes called system LSIs, super LSIs, or ultra LSIs, depending on the degree of integration.

Also, the integrated circuit is not limited to an LSI, and may be realized by a dedicated circuit or a general-purpose processor. As described above, a programmable FPGA or a reconfigurable processor in which connections and settings of circuit cells inside the LSI can be reconfigured may be used.

Furthermore, if an integrated circuit technology that replaces LSI appears due to advances in semiconductor technology or another technology derived from it, naturally, using that technology, each component included in the broadcast receiver 12 will be integrated. may

In addition, the present disclosure also includes forms realized by arbitrarily combining the components and functions in each embodiment without departing from the scope of the present disclosure.

The broadcast receiving device of the present disclosure can be used as a tuner device provided in, for example, a television receiver.

REFERENCE SIGNS LIST 10 television receiver 12 broadcast receiver 14 first decoding unit 16 second decoding unit 20 tuner unit 22 demodulation circuit 24, 44 demapping circuit 26, 46 deinterleaving circuit 28, 48 error correction decoding circuit 30 subtractor 32 multiplier 34 Mapping Circuit 36 Interleave Circuit 38 Error Correction Encoding Circuit 40 Delay Circuit 50 Selector 52 Multiplexed Signal Demultiplexer 54 Video/Audio Decoder 56 Video Synthesizer 58 Control Unit 60 Audio Output Unit 62 Video Display Unit

Claims (6)

The first digital broadcast signal modulated by the first modulation method and the second digital broadcast signal modulated by the second modulation method are divided into high power layers and low power layers by the LDM (Layered Division Multiplexing) method, respectively. A broadcast reception method in which a broadcast receiver receives digital broadcast signals that are multiplexed and transmitted,
an extraction step of receiving the first digital broadcast signal and extracting transmission information for notifying transmission of the second digital broadcast signal from the first digital broadcast signal;
a obtaining step of obtaining a signal-to-noise ratio of the first digital broadcast signal;
Based on the injection level information indicating the signal level ratio between the high-power hierarchy and the low-power hierarchy and the signal-to-noise ratio of the first digital broadcast signal, the second digital broadcast signal is included in the transmission information. a determination step of determining whether or not a broadcast signal can be received. 2. The broadcast receiving method according to claim 1, wherein in said obtaining step, position information indicating a current position of said broadcast receiving device is obtained, and a signal-to-noise ratio of said first digital broadcast signal is calculated based on said position information. . The first digital broadcast signal includes a TMCC (Transmission and Multiplexing Configuration Control) signal,
3. The broadcast reception method according to claim 1, wherein the transmission information is included in the TMCC signal. The first digital broadcast signal includes an SDTT (Software Download Trigger Table) signal,
3. The broadcast reception method according to claim 1, wherein the transmission information is included in the SDTT signal. 5. The broadcast receiving method according to any one of claims 1 to 4, further comprising a notification step of notifying that reception is impossible when said determination step determines that reception is impossible. A digital broadcasting signal in which a first digital broadcasting signal modulated by a first modulation method and a second digital broadcasting signal modulated by a second modulation method are hierarchically division-multiplexed by the LDM (Layered Division Multiplexing) method and transmitted. A broadcast receiving device for receiving,
an extraction unit that receives the first digital broadcast signal and extracts transmission information for notifying transmission of the second digital broadcast signal from the first digital broadcast signal;
The second A broadcast receiver, comprising: a control unit that determines whether or not a digital broadcast signal can be received.

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