Transmission device, transmission method, reception device, and reception method

Abstract

The present disclosure relates to a transmission device, a transmission method, a reception device, and a reception method which make it possible to provide various broadcasting services. Provided is a transmission device comprising: a multiplexing unit that uses an LDM technique to multiplex a first signal transmitted via a first layer multiplexed at a first electric power, and a second signal transmitted via a second layer multiplexed at a second electric power differing from the first electric power; a generation unit that generates control information; and a construction unit that constructs a physical layer frame using a multiplexed signal and the control information, wherein the control information contains information expressing the provider associated with each layer in the second layer for each subframe included in the physical layer frame. The present disclosure can be applied to, for example, a transmission scheme compatible with an ISDB-T next-generation broadcasting scheme.

Description

Transmitting device, transmitting method, receiving device, and receiving method

[0001] The present disclosure relates to a transmitting device, a transmitting method, a receiving device, and a receiving method, and more particularly to a transmitting device, a transmitting method, a receiving device, and a receiving method that are capable of providing various broadcast services.

[0002] In Japan, advancements to the next generation of terrestrial digital television broadcasting are being studied, and various technical methods are being investigated. For example, the introduction of Layered Division Multiplexing (LDM) is being considered. In the LDM method, broadcast signals are transmitted by layer-division multiplexing high-power and low-power layers in the same frequency band (see, for example, Patent Document 1).

[0003] Japanese Patent Publication No. 2020-150521

[0004] There has been discussion about adopting the LDM method to enable the provision of various broadcasting services, but such a technical method has not yet been established, and there has been a demand for proposals for technologies to provide various broadcasting services.

[0005] The present disclosure has been made in light of these circumstances, and makes it possible to provide a variety of broadcasting services.

[0006] A transmitting device according to one aspect of the present disclosure includes a multiplexing unit that multiplexes a first signal transmitted by a first layer that is multiplexed at a first power and a second signal transmitted by a second layer that is multiplexed at a second power different from the first power using an LDM method, a generating unit that generates control information, and a component that constructs a physical layer frame using the multiplexed signal and the control information, wherein the control information includes information indicating an operator for each hierarchical level in the second layer for each subframe included in the physical layer frame.

[0007] A transmission method according to one aspect of the present disclosure is a transmission method in which a transmitting device multiplexes a first signal transmitted by a first layer, the first signal being multiplexed at a first power, and a second signal transmitted by a second layer, the second signal being multiplexed at a second power different from the first power, using an LDM method, generates control information, and constructs a physical layer frame using the multiplexed signal and the control information, the control information including, for each subframe included in the physical layer frame, information indicating an operator for each hierarchical level in the second layer.

[0008] In a transmission device and a transmission method according to one aspect of the present disclosure, a first signal to be transmitted by a first layer and multiplexed at a first power and a second signal to be transmitted by a second layer and multiplexed at a second power different from the first power are multiplexed using an LDM scheme to generate control information, and a physical layer frame is configured using the multiplexed signal and the control information. Furthermore, the control information includes, for each subframe included in the physical layer frame, information indicating an operator for each hierarchical layer in the second layer.

[0009] A receiving device according to one aspect of the present disclosure includes a first demodulation unit that demodulates control information included in a physical layer frame transmitted from a transmitting device, and a second demodulation unit that demodulates a first signal and a second signal multiplexed using an LDM method included in the physical layer frame based on the demodulated control information, wherein the first signal is transmitted by a first layer in which the first signal is multiplexed at a first power using the LDM method, and the second signal is transmitted by a second layer in which the second signal is multiplexed at a second power different from the first power using the LDM method, and the control information includes information indicating an operator for each hierarchy in the second layer for each subframe included in the physical layer frame.

[0010] A receiving method according to one aspect of the present disclosure includes a receiving device demodulating control information included in a physical layer frame transmitted from a transmitting device, and demodulating, based on the demodulated control information, a first signal and a second signal multiplexed using an LDM method included in the physical layer frame, wherein the first signal is transmitted by a first layer multiplexed at a first power using the LDM method, and the second signal is transmitted by a second layer multiplexed at a second power different from the first power using the LDM method, and the control information includes, for each subframe included in the physical layer frame, information indicating an operator for each hierarchy in the second layer.

[0011] In a receiving device and a receiving method according to one aspect of the present disclosure, control information included in a physical layer frame transmitted from a transmitting device is demodulated, and a first signal and a second signal multiplexed by an LDM method and included in the physical layer frame are demodulated based on the demodulated control information. The first signal is transmitted by a first layer in which the first signal is multiplexed at a first power according to the LDM method, and the second signal is transmitted by a second layer in which the second signal is multiplexed at a second power according to the LDM method that is different from the first power. The control information includes, for each subframe included in the physical layer frame, information indicating an operator for each hierarchical layer in the second layer.

[0012] The transmitting device and receiving device according to one aspect of the present disclosure may be independent devices or may be internal blocks constituting a single device.

[0013] 1 is a block diagram showing an example configuration of an embodiment of a transmission system to which the present disclosure is applied. FIG. 1 is a diagram illustrating transmission by the LDM method. FIG. 2 is a block diagram showing an example configuration of an embodiment of the transmitting device of FIG. 1. FIG. 3 is a block diagram showing an example configuration of an embodiment of the receiving device of FIG. 1. FIG. 4 is a diagram illustrating an example configuration of a physical layer frame. FIG. 5 is a diagram illustrating an example configuration of TMCC information. FIG. 6 is a diagram illustrating an example configuration of transmission control auxiliary information. FIG. 7 is a diagram illustrating a first example configuration of LDM configuration information. FIG. 8 is a diagram illustrating a second example configuration of LDM configuration information. FIG. 9 is a diagram illustrating a third example configuration of LDM configuration information. FIG. 10 is a diagram illustrating an example configuration of subframes and layers in an LDM configuration, and layer group IDs. FIG. 11 is a diagram schematically illustrating an example relationship between UL and LL layers in a subframe. FIG. 12 is a flowchart illustrating the flow of transmitting-side processing. FIG. 13 is a flowchart illustrating the flow of receiving-side processing. FIG. 14 is a block diagram illustrating an example configuration of a computer.

[0014] <System Configuration> Fig. 1 is a block diagram showing an example configuration of an embodiment of a transmission system to which the present disclosure is applied. In Fig. 1, the transmission system is composed of a transmitting device 10 and a receiving device 20. Note that a system refers to a logical collection of multiple devices.

[0015] The transmitting device 10 transmits content such as broadcast programs produced by a broadcast station as broadcast signals. The transmitting device 10 performs necessary processing on control information and content data, and transmits the resulting broadcast signals from a transmitting antenna installed at a transmitting station.

[0016] The receiving device 20 is a device capable of receiving broadcast signals, such as a fixed receiver such as a television set, or a mobile receiver such as a mobile phone. The receiving device 20 receives the broadcast signals transmitted from the transmitting device 10 via an antenna. The receiving device 20 performs necessary processing on the control information and data obtained from the received broadcast signals, thereby outputting video and audio of content such as a broadcast program.

[0017] The transmission system shown in Figure 1 can use the terrestrial digital television broadcasting standard. In Japan, the ISDB-T (Integrated Services Digital Broadcasting - Terrestrial) standard is used, but studies are underway to upgrade it to the next generation, and various technical standards are being considered. Hereinafter, the next generation of ISDB-T standards will also be referred to as the terrestrial broadcasting standard.

[0018] For example, in the advanced terrestrial broadcasting system, the introduction of a layered division multiplexing system (hereinafter referred to as LDM system) is being considered. Figure 2 is a diagram explaining transmission using the LDM system. In Figure 2, the vertical axis represents signal level and the horizontal axis represents frequency.

[0019] Figure 2 shows the frequency band of one channel, and each frequency band consists of multiple segments (for example, 13 segments in the ISDB-T system). As shown in Figure 2, LDM transmission allows broadcast signals to be transmitted by overlapping them in the same frequency band using a high-power layer as the upper layer (UL) and a low-power layer as the lower layer (LL). When providing a multi-stream broadcast service using the LDM system, a first stream broadcast signal can be transmitted using the high-power layer (UL) and a second stream broadcast signal can be transmitted using the low-power layer (LL).

[0020] For example, a multi-stream broadcasting service can provide video with a resolution corresponding to a signal that can be demodulated on the receiving side. More specifically, video with a resolution corresponding to a signal that can be demodulated is provided based on a carrier-to-noise ratio (CN ratio), which varies depending on the reception environment of the receiving device 20. Transmission using the LDM method enables efficient transmission of video with different resolutions. Hereinafter, when the advanced terrestrial broadcasting method is adopted, a broadcasting service provided by transmission without using the LDM method is referred to as a normal broadcasting service, and a broadcasting service provided by transmission using the LDM method is referred to as a specific broadcasting service.

[0021] Fig. 3 is a block diagram showing an example of the configuration of an embodiment of the transmitting device 10 of Fig. 1. In Fig. 3, the transmitting device 10 includes a UL processing unit 101, an LL processing unit 102, an LDM multiplexing unit 103, a selecting unit 104, a control information generating unit 105, and a frame configuring unit 106.

[0022] The UL processing unit 101 performs physical layer processing, such as encoding and modulation using error correction codes, on the signals input thereto. That is, when LDM transmission is not performed, the UL processing unit 101 performs necessary processing, such as encoding, on signals of content provided by a normal broadcast service, and outputs the processed signals to the selection unit 104. When LDM transmission is performed, the UL processing unit 101 performs necessary processing, such as encoding, on signals of a first stream (hereinafter also referred to as an UL signal) transmitted by a high-power layer (UL) among signals of content provided by a specific broadcast service, and outputs the processed UL signal to the LDM multiplexing unit 103.

[0023] The LL processing unit 102 performs physical layer processing such as encoding and modulation using error correction codes on the signals input thereto. That is, when performing LDM transmission, the LL processing unit 102 performs necessary processing such as encoding on a second stream signal (hereinafter also referred to as an LL signal) transmitted by the low power layer (LL) among signals of content provided by a specific broadcast service, and outputs the processed LL signal to the LDM multiplexing unit 103.

[0024] The LDM multiplexing section 103 adjusts the power levels of the UL signal input from the UL processing section 101 and the LL signal input from the LL processing section 102, then multiplexes them using the LDM method and outputs the multiplexed signal to the selection section 104. In accordance with a selection signal from the control device, the selection section 104 selects either the normal broadcast service signal input from the UL processing section 101 or the LDM-multiplexed signal input from the LDM multiplexing section 103, and outputs this to the frame configuration section 106. That is, when LDM transmission is not performed, the normal broadcast service signal is selected, and when LDM transmission is performed, the LDM-multiplexed signal is selected and output to the frame configuration section 106.

[0025] The control information generator 105 generates control information related to the physical layer and outputs it to the frame constructor 106. The frame constructor 106 constructs a physical layer frame using the signal (data signal) input from the selector 104 and the control information (control information signal) input from the control information generator 105. The transmitter 10 performs necessary processing such as IFFT (Inverse Fast Fourier Transform) and GI (Guard Interval) addition, thereby modulating the physical layer frame to generate a broadcast signal, which is then transmitted from a transmitting antenna installed at the transmitting station.

[0026] Fig. 4 is a block diagram showing an example of the configuration of an embodiment of the receiving device 20 of Fig. 1. In Fig. 4, the receiving device 20 includes a demodulation unit 201 and a processing unit 202.

[0027] The demodulation unit 201 is composed of a tuner and a demodulation device (such as a demodulation LSI). The demodulation unit 201 demodulates a physical layer frame from a broadcast signal received via an antenna and performs necessary processing on the physical layer frame. The demodulation unit 201 has a control information demodulation unit 211, a UL demodulation unit 212, and an LL demodulation unit 213.

[0028] The control information demodulation unit 211 demodulates the control information included in the physical layer frame. The demodulation unit 201 performs demodulation processing based on the control information obtained from the physical layer frame. When LDM transmission is not performed, the demodulation processing is performed by the UL demodulation unit 212. That is, the UL demodulation unit 212 performs demodulation processing to demodulate the data signal included in the physical layer frame. When LDM transmission is not performed, the demodulation unit 201 outputs the data signal demodulated by the UL demodulation unit 212, which is a signal of content provided by a normal broadcast service, to the processing unit 202.

[0029] When LDM transmission is performed, demodulation processing is performed by the UL demodulation unit 212 and the LL demodulation unit 213. That is, the UL demodulation unit 212 performs UL demodulation processing to demodulate the UL signal included in the physical layer frame, and the LL demodulation unit 213 performs LL demodulation processing to demodulate the LL signal included in the physical layer frame. For example, when performing LDM demodulation processing using successive interference cancellation (SIC), the UL signal is demodulated from the LDM-multiplexed signal, and the demodulated UL signal is re-modulated to generate a replica signal, and the replica signal is subtracted from the LDM-multiplexed signal to demodulate the LL signal. The demodulation unit 201 outputs the UL signal demodulated by the UL demodulation unit 212 and the LL signal demodulated by the LL demodulation unit 213 to the processing unit 202. That is, when LDM transmission is performed, the UL signal and the LL signal are output to the processing unit 202 as signals of content provided by a specific broadcast service.

[0030] The processing unit 202 is configured with a main SoC (System on Chip) or the like. The processing unit 202 performs necessary processing related to decoding, presentation, etc. on the signal input from the demodulation unit 201. When LDM transmission is not performed, the processing unit 202 performs necessary processing on the signal input from the demodulation unit 201 to acquire video and audio data of content provided by the normal broadcast service. When LDM transmission is performed, the processing unit 202 performs necessary processing on the UL signal and LL signal input from the demodulation unit 201 to acquire video and audio data of content provided by the specific broadcast service.

[0031] The video and audio data obtained by processing by the processing unit 202 is output to a subsequent circuit, whereby the receiving device 20 displays video of content such as a broadcast program on the display, and outputs audio synchronized with the video from the speaker.

[0032] While the configuration of FIG. 1 illustrates a single receiving device 20, in practice, multiple receiving devices 20 may be provided, each of which may receive and process a broadcast signal transmitted from the transmitting device 10. Furthermore, while the configuration of FIG. 3 illustrates a configuration in which the transmitting device 10 includes the UL processing unit 101, the LL processing unit 102, the LDM multiplexing unit 103, the selection unit 104, the control information generating unit 105, and the frame constructing unit 106, these blocks do not necessarily need to be provided within a single housing. For example, the transmitting device 10 may be configured as a transmission system (broadcast transmission system) in which at least one block is provided in a separate device (broadcast server). While the configuration of FIG. 4 illustrates a configuration in which the demodulation unit 201 of the receiving device 20 includes two demodulation units (the UL demodulation unit 212 and the LL demodulation unit 213), the UL demodulation unit 212 and the LL demodulation unit 213 may be configured in a single demodulation unit (demodulator).

[0033] <Physical Layer Frame Structure> For the Advanced Terrestrial Broadcasting Standard, it is being considered to adopt the Orthogonal Frequency Division Multiplexing (OFDM) method, as with the current ISDB-T standard. In other words, for the Advanced Terrestrial Broadcasting Standard, it is being considered to use OFDM frames as the physical layer frame, as with the ISDB-T standard. Furthermore, for the Advanced Terrestrial Broadcasting Standard, it is being considered to provide services using hierarchical transmission with a segment structure in which one channel is divided into segments, as with the current ISDB-T standard. However, for the Advanced Terrestrial Broadcasting Standard, it is being considered to increase the number of segments used for signal transmission from 13 to 35 segments, thereby increasing the number of segments.

[0034] Figure 5 shows an example of the structure of a physical layer frame for the advanced terrestrial broadcasting standard. In Figure 5, the horizontal axis represents time and the vertical axis represents frequency. The frequency bandwidth represents the bandwidth of one channel (e.g., 5.83 MHz) and can be divided into multiple segments.

[0035] As shown in Figure 5, the physical layer frame of the advanced terrestrial broadcasting standard consists of a frame synchronization signal section, a TMCC section, one or more subframe sections, and an extension section. The frame synchronization signal section transmits synchronization signals, TMCC modulation parameters, etc. The TMCC section transmits transmission control information including information about the entire frame (time information, etc.) and modulation parameters for subframes and layers. Additionally, the TMCC section transmits auxiliary transmission control information (Auxiliary_data) as information for the extension section.

[0036] In order to realize a variety of hierarchical transmissions that take into account various reception environments, the subframe section can be configured using frequency division multiplexing, time division multiplexing, or a combination of frequency division multiplexing and time division multiplexing. Figure 5 shows an example of a configuration in which subframes with multiple frequency divisions are allocated to services for mobile reception, and subframes allocated to services for fixed receivers with different FFT sizes are time division multiplexed. An extension section can be provided at the end of the physical layer frame for future expansion.

[0037] <Control Information Structure> Figure 6 is a diagram showing an example of the structure of TMCC information in a TMCC section. As shown in Figure 6, the TMCC information includes size, which indicates the size of the entire TMCC information, update_count, which indicates the update count of the TMCC information, countdown_index, which indicates a transmission parameter switching indicator, and time_info_flag, which indicates whether a time information field is present. If a time information field is present, it includes ntp_leap_indicator, which indicates a leap second indicator, and ntp_time, which indicates the time in NTP (Network Time Protocol) format.

[0038] The TMCC information includes an emergency_warning_broadcast_system_flag that indicates whether an emergency warning broadcast (EWS: Emergency Warning Broadcast System) is available, and an earthquake_early_warning_flag that indicates whether an earthquake early warning (EEW: Earthquake Early Warning) is available. If an earthquake early warning is available, the TMCC information includes earthquake_early_warning_data that indicates the earthquake early warning data.

[0039] The TMCC information includes Frame_configuration indicating the frame configuration, Subframe_configuration indicating the subframe configuration, Layer_configuration indicating the layer configuration, and Sublayer_configuration indicating the sublayer configuration.

[0040] Frame_configuration includes number_of_subframes indicating the number of subframes, inter_subframe_interleave indicating the number of divisions in inter-subframe interleaving, pilot_phase indicating the pilot phase, and wake_up_group indicating the wake-up group.

[0041] Subframe_configuration is arranged according to the number of subframes indicated by number_of_subframes. Subframe_configuration includes partial_reception_flag indicating whether the central segment of the transmission band is set to a partial reception band, fft_size indicating the FFT size, gi_fraction indicating the GI ratio, number_of_symbols indicating the number of symbols, number_of_layers indicating the number of layers, and wireless_transmission_system indicating the wireless transmission system.

[0042] Layer_configuration is arranged according to the number of layers indicated by number_of_layers. Layer_configuration includes number_of_sublayers indicating the number of sub-layers, sp_pattern indicating the SP pattern, sp_coding indicating the SP coding method, start_boundary_pilot indicating whether or not there is a boundary pilot in the first symbol of the subframe, end_boundary_pilot indicating whether or not there is a boundary pilot in the last symbol of the subframe, sp_level indicating the SP level (SP boost ratio), time_interleave indicating the time interleave length, and group_id indicating a group identifier. group_id is an ID that identifies the operator providing the broadcasting service.

[0043] Sublayer_configuration is arranged according to the number of sublayers indicated by number_of_sublayers. Sublayer_configuration includes number_of_subsegments indicating the number of subsegments, carrier_modulation indicating the carrier modulation method, constellation_type indicating the constellation identification, code_length indicating the code length of the inner code, code_rate indicating the coding rate of the inner code, fec_block_pointer indicating a value according to the number of carrier symbols from the start of the frame to the start of the FEC block, and data_carrier_boost indicating the data carrier boost.

[0044] Auxiliary_data contains auxiliary transmission control information. In the present disclosure, LDM configuration information related to the configuration of LDM transmission can be included in the auxiliary transmission control information and transmitted. Figure 7 is a diagram showing an example of the configuration of the auxiliary transmission control information.

[0045] The 8-bit number_of_aux_data indicates the number of auxiliary transmission control information. Within the loop corresponding to the number indicated by number_of_aux_data, an 8-bit aux_data_type and an 8-bit aux_data_size are placed. The aux_data_type indicates the type that identifies the auxiliary transmission control information. The aux_data_size indicates the size (number of bits) of the auxiliary transmission control information.

[0046] When aux_data_type = 3, aux_ldm_configuration is placed in the loop. aux_ldm_configuration is LDM configuration information that includes LDM configuration information. LDM configuration information can also be considered control information that indicates the subframe and layer configuration when LDM transmission is performed. Configuration examples of LDM configuration information are shown in Figures 8 to 10.

[0047] Fig. 8 is a diagram showing a first example of the configuration of LDM configuration information. As shown in Fig. 8, a nested structure is formed in which a second loop corresponding to the number of layers indicated by number_of_layers is described within a first loop corresponding to the number of subframes indicated by number_of_subframes, and the second loop is repeated according to the number of iterations of the first loop.

[0048] A 1-bit ldm_flag is placed in the second loop. ldm_flag is a flag that indicates whether or not LDM transmission is used. If 0 is specified as the value of ldm_flag, it indicates that LDM transmission is used, and if 1 is specified, it indicates that LDM transmission is not used.

[0049] In the second loop, if the value of ldm_flag is 0, a 3-bit ldm_group_id and a 16-bit ldm_fec_block_pointer are placed. ldm_group_id is an identifier indicating the operator. ldm_fec_block_pointer is the FEC block pointer. The FEC block pointer is information indicating the start position of the first FEC block within the subframe.

[0050] The LDM modulation parameters are placed after the first loop. The 3-bit ldm_carrier_modulation indicates the carrier modulation method. The 1-bit ldm_constellation_type indicates the constellation identification. The 2-bit ldm_code_length indicates the code length. The 4-bit ldm_code_rate indicates the coding rate. The 5-bit ldm_injection_level indicates the injection level.

[0051] In Figure 8, when LDM transmission is used, the FFT size, GI, SP pattern, time interleave length, and number of subsegments of the signal transmitted in the low-power layer (LL) are the same as those of the signal transmitted in the high-power layer (UL). Information about the signal transmitted in the high-power layer (UL) is placed in the TMCC information (Figure 6). The LDM modulation parameters in Figure 8 correspond to the modulation parameters of the signal transmitted in the low-power layer (LL). In Figure 8, the LDM modulation parameters are common to all subframes, but they may be specified for each layer by adding them to the ldm_fec_block_pointer in the second loop.

[0052] 9 is a diagram showing a second example of the configuration of the LDM configuration information. As shown in Fig. 9, a nested structure is formed in which a second loop corresponding to the number of layers indicated by number_of_layers is described within a first loop corresponding to the number of subframes indicated by number_of_subframes, and the second loop is repeated according to the number of iterations of the first loop.

[0053] A 1-bit ldm_flag is placed in the second loop. ldm_flag is a flag that indicates whether or not LDM transmission is used, which constitutes the same broadcast service as the UL layer. If 0 is specified as the value of ldm_flag, it indicates that LDM transmission is used, and if 1 is specified, it indicates that LDM transmission is not used. As will be described in detail later, when LDM transmission is used and the UL layer and LL layer constitute the same broadcast service, the group ID of the LL layer is the same as the group ID (group_id) of the UL layer, so there is no need to place ldm_group_id.

[0054] In the second loop, if the value of ldm_flag is 0, a 16-bit ldm_fec_block_pointer is allocated. The ldm_fec_block_pointer is the FEC block pointer.

[0055] LDM modulation parameters are placed after the first loop. In Figure 9, the LDM modulation parameters are the same as in Figure 8 and may be common to all subframes, or may be specified for each layer by adding them to the ldm_fec_block_pointer in the second loop. Note that in Figure 9, when LDM transmission is used, the FFT size, GI, SP pattern, time interleave length, number of subsegments, and group ID (group_id) of the signal transmitted in the low power layer (LL) are the same as those of the signal transmitted in the high power layer (UL).

[0056] 10 is a diagram showing a third example of the configuration of LDM configuration information. As shown in FIG. 10, a 3-bit number_of_ldm_layers is placed in a first loop corresponding to the number of subframes indicated by number_of_subframes. number_of_ldm_layers indicates the number of layers using LDM transmission. A nested structure is formed in which a second loop corresponding to the number of layers indicated by number_of_ldm_layers is described within the first loop, and the second loop is repeated according to the number of iterations of the first loop.

[0057] The second loop contains a 3-bit ldm_group_id, a 7-bit ldm_number_of_subsegments, and a 16-bit ldm_fec_block_pointer. ldm_group_id is an identifier that indicates the provider. ldm_number_of_subsegments indicates the number of subsegments in the tier. ldm_fec_block_pointer is the FEC block pointer.

[0058] The LDM modulation parameters are placed after the first loop. In Figure 10, the LDM modulation parameters are the same as those in Figure 8, and may be common to all subframes, or may be specified for each layer by adding them to the ldm_fec_block_pointer in the second loop. In Figure 10, the FFT size, GI, SP pattern, and time interleaving length of the signal transmitted in the low-power layer (LL) are the same as those of the signal transmitted in the high-power layer (UL).

[0059] <Operation Example> An operation example when using the LDM configuration information of Figures 8 to 10 will be described with reference to Figures 11 and 12. Figure 11 is a diagram showing an example of the subframe and hierarchical configuration in an LDM configuration, and the hierarchical group ID. Figure 11 summarizes the subframe and hierarchical configuration and the method of specifying the hierarchical group ID for each type of LDM configuration. Figure 12 is a diagram schematically showing an example of the hierarchical relationship between the high power hierarchical layer (UL) and the low power hierarchical layer (LL) in a subframe.

[0060] In FIG. 11 , when LDM transmission is performed, LDM configuration #1 has the same configuration as the UL subframes and layers for LL. In the case of LDM configuration #1, the LDM configuration information in FIG. 8 can be used to specify the LL group ID. That is, in the LDM configuration information in FIG. 8 , based on the number_of_subframes and number_of_layers included in the TMCC information, a first loop corresponding to the number of subframes indicated by number_of_subframes and a second loop corresponding to the number of layers indicated by number_of_layers can be used, and ldm_group_id can be placed in the second loop. In this way, the group ID for each LL layer can be specified by ldm_group_id.

[0061] Figure 12A shows the subframe and layer configuration corresponding to LDM configuration #1, with the UL and LL having the same subframe and layer configuration. In Figure 12A, three layers, A, B, and C, are assigned to the UL and LL in the same subframe. The UL layer A (UL-A) and the LL layer A (LL-A), the UL layer B (UL-B) and the LL layer B (LL-B), and the UL layer C (UL-C) and the LL layer C (LL-C) correspond to each other and have the same layer configuration. In this case, the group IDs of each LL layer (LL-A, LL-B, LL-C) can be specified by the ldm_group_id in the second loop of the LDM configuration information in Figure 8. The group IDs of each UL layer (UL-A, UL-B, UL-C) can be specified by the group_id in the TMCC information (Figure 6).

[0062] In FIG. 11 , in LDM configuration #2, when LDM transmission is performed, the LL subframes and layers are configured identically to the UL subframes and layers. In the case of LDM configuration #2, the LL group ID can be specified by using the LDM configuration information of FIG. 9 . In the LDM configuration information of FIG. 9 , a first loop corresponding to the number of subframes indicated by number_of_subframes and a second loop corresponding to the number of layers indicated by number_of_layers are used, and ldm_flag can be placed in the second loop. In this way, it is possible to specify, for each LL layer, whether or not LDM transmission constituting the same broadcast service as the UL layer is performed. In other words, when the LL subframe and layer configuration is identical to the UL, the group ID of the LL layer is the same as the group ID (group_id) of the UL layer. Therefore, by indicating the use of LDM transmission using ldm_flag, the group ID (group_id) of the UL layer can be used as the group ID of the LL layer.

[0063] Figure 12B shows a subframe and layer configuration corresponding to LDM configuration #2, with the UL and LL having the same subframe and layer configuration. In Figure 12B, similar to Figure 12A, three layers, A, B, and C, are assigned to the UL and LL in the same subframe. In Figure 12B, for example, if the LL's B layer (LL-B) uses LDM transmission that constitutes the same broadcast service as the UL's B layer (UL-B), the group ID of the LL's B layer (LL-B) is the same as the group ID of the UL's B layer (UL-B), and can be specified by the group_id in the TMCC information (Figure 6). Note that group IDs can also be specified for the UL's A layer (UL-A) and LL's A layer (LL-A), and for the UL's C layer (UL-C) and LL's C layer (LL-C).

[0064] In FIG. 11 , LDM configuration #3 is a configuration in which the LL subframes and layers are different from the UL subframes and layers when LDM transmission is performed. In the case of LDM configuration #3, the LL group ID can be specified by using the LDM configuration information in FIG. 10 . The LDM configuration information in FIG. 10 uses a first loop corresponding to the number of subframes indicated by number_of_subframes included in the TMCC information, and a second loop corresponding to the number of layers indicated by number_of_ldm_layers included in the LDM configuration information, and ldm_group_id can be placed in the second loop. In this way, the group ID for each LL layer can be specified by ldm_group_id.

[0065] Figure 12C shows a subframe and layer configuration corresponding to LDM configuration #3. The UL and LL have different layers, resulting in different subframe and layer configurations. In Figure 12C, three layers (layers A, B, and C) are assigned to the UL in the same subframe, and two layers (layers A and B) are assigned to the LL. That is, layer A of the LL (LL-A) and layer B of the LL (LL-B) do not correspond to layer A of the UL (UL-A), layer B of the UL (UL-B), and layer C of the UL (UL-C), resulting in different layer configurations. In this case, the group IDs of each LL layer (LL-A, LL-B) can be specified by the ldm_group_id in the second loop of the LDM configuration information in Figure 10. The group IDs of each UL layer (UL-A, UL-B, UL-C) can be specified by the group_id in the TMCC information (Figure 6). Furthermore, when performing LDM transmission, control information can be transmitted for each layer of the subframe included in the physical layer frame.

[0066] As described above, when transmitting using the LDM method, by transmitting information (ldm_group_id) indicating the operator for each LL layer in the LDM configuration information, for example, it is possible to indicate signals corresponding to each UL and LL layer using group IDs (group_id, ldm_group_id) with the same value. This allows the receiving device 20 to identify signals (UL signals and LL signals) to be simultaneously demodulated using the group IDs (group_id, ldm_group_id) included in the control information. In FIG. 11, an example is shown in which LDM configuration #1 includes ldm_group_id for each LL layer when the LL subframe and layer configuration is the same as the UL configuration (FIGS. 8 and 12A). Furthermore, an example is shown in which LDM configuration #3 includes ldm_group_id for each LL layer when the LL subframe and layer configuration is different from the UL configuration (FIGS. 10 and 12C).

[0067] In Figure 11, LDM configuration #2 shows an example in which, when the LL subframe and layer configuration is the same as the UL configuration, the LDM configuration information does not include information (ldm_group_id) indicating the operator for each LL layer, and corresponding signals are identified for each UL and LL layer. That is, in LDM configuration #2, the group ID of the LL layer is the same as the group ID (group_id) of the UL layer, so the LDM configuration information does not include ldm_group_id, and ldm_flag is defined as a flag indicating the presence or absence of LDM transmission that constitutes the same broadcast service as the UL layer (Figures 9 and 12B). In this case, too, the group ID (group_id) of the UL layer can indirectly specify information (group_id) indicating the operator for each LL layer.

[0068] <Transmitting Side and Receiving Side Processing> Fig. 13 is a flowchart illustrating the flow of transmitting side processing executed by the transmitting device 10 in Fig. 3. In the transmitting side processing in Fig. 13, a case where LDM transmission is performed will be described.

[0069] In step S11, the UL processing unit 101 performs UL processing according to the UL signal transmitted in the high-power layer (UL). In step S12, the LL processing unit 102 performs LL processing according to the LL signal transmitted in the low-power layer (LL). In step S13, the LDM multiplexing unit 103 multiplexes the UL signal obtained by the UL processing and the LL signal obtained by the LL processing using the LDM method.

[0070] In step S14, the control information generator 105 generates control information such as TMCC information. The control information includes auxiliary transmission control information including LDM configuration information. For example, the LDM configuration information may have any of the configurations shown in Figures 8 to 10. The control information may be generated before the processing of steps S11 to S13, or, if the information included in the control information is the same, the generated control information may be recorded in a memory or the like and used.

[0071] In step S15, the frame constructor 106 constructs a physical layer frame such as an OFDM frame using the LDM multiplexed signal and the control information. The broadcast signal obtained by modulating the physical layer frame is transmitted from the broadcast antenna.

[0072] Fig. 14 is a flowchart illustrating the flow of the receiving-side process executed by the receiving device 20 of Fig. 4. In the receiving-side process of Fig. 14, a case where LDM transmission is performed corresponding to the transmitting-side process of Fig. 13 will be described.

[0073] In step S21, the demodulator 201 receives a physical layer frame obtained from a broadcast signal transmitted from the transmitter 10. In step S22, the control information demodulator 211 demodulates the control information included in the physical layer frame.

[0074] In step S23, the UL demodulation unit 212 performs UL demodulation processing to demodulate the UL signal included in the physical layer frame based on the demodulated control information. In step S24, the LL demodulation unit 213 performs LL demodulation processing to demodulate the LL signal included in the physical layer frame based on the demodulated control information.

[0075] When performing UL demodulation processing and LL demodulation processing in demodulation section 201, it is possible to identify signals to be simultaneously demodulated (UL signal and LL signal) by using group IDs included in the control information, i.e., group_id included in the TMCC information and ldm_group_id included in the LDM configuration information transmitted as transmission control auxiliary information. Furthermore, in the case of performing LDM demodulation processing using successive interference cancellation (SIC), for example, demodulation section 201 can perform UL re-modulation processing using the UL signal obtained in the UL demodulation processing, and can perform LL demodulation processing using a signal obtained by subtracting the replica signal obtained in the UL re-modulation processing from the signal before UL demodulation.

[0076] In step S25, the processing unit 202 processes the UL and LL streams based on the UL signal obtained by the UL demodulation process and the LL signal obtained by the LL demodulation process, thereby presenting the video and audio of the broadcast program. For example, if a broadcast service that provides video with a resolution corresponding to a signal that can be demodulated on the receiving side is provided as a specific broadcast service, the receiving device 20 can display video with a resolution corresponding to the reception environment from a signal demodulated according to a CN ratio that varies depending on the reception environment. Here, the larger the CN ratio value, the higher the resolution of the video that is displayed, while the smaller the CN ratio value, the lower the resolution of the video that is displayed.

[0077] Note that the indicator of the reception level is not limited to the CN ratio, and other indicators may be used. The specific broadcast service using LDM transmission is not limited to a broadcast service that provides video with a resolution corresponding to a signal that can be demodulated on the receiving side, and other specific broadcast services may be provided. For example, the specific broadcast service may be a broadcast service that can provide video and audio of higher quality than that provided by a normal broadcast service. In this case, the normal broadcast service signal may be transmitted on the high power hierarchical layer (UL), and the signal required to provide the higher quality video and audio in the specific broadcast service may be transmitted on the low power hierarchical layer (LL).

[0078] As described above, in the present disclosure, when LDM transmission is performed, the LDM configuration information included in the transmission control auxiliary information transmitted as control information includes information (ldm_group_id) indicating a carrier for each LL layer for each subframe included in the physical layer frame. Therefore, the group IDs (group_id, ldm_group_id) indicate the corresponding signals for each UL and LL layer. Therefore, even when a single broadcast service is provided using multiple signals transmitted in the UL and LL layers using LDM transmission, the receiving device 20 can identify the signals (UL signal and LL signal) to be simultaneously demodulated from the information (group_id, ldm_group_id) indicating the carrier. In this way, the receiving device 20 can correctly receive the LDM signals (UL signal and LL signal) that constitute the multi-stream, thereby enabling the provision of various broadcast services, including specific broadcast services.

[0079] Although the above description has been given of an advanced terrestrial broadcasting system, which is the next generation system of ISDB-T, as a broadcasting system for terrestrial digital television broadcasting, the present disclosure may be applied to other broadcasting systems. Furthermore, the present disclosure is not limited to terrestrial waves (terrestrial broadcasting), and may be applied to broadcasting systems such as broadcasting satellites (BS), communications satellites, or cable broadcasting (CATV: Common Antenna Television).

[0080] In the above description, the receiving device 20 is a television receiver, but the fixed receiver may be, for example, an electronic device such as a set-top box (STB), a recording device, a game console, or a personal computer (PC). Furthermore, the receiving device 20 is a mobile phone, but the mobile receiver may be, for example, an electronic device such as a smartphone or a tablet computer. Furthermore, the receiving device is not limited to a fixed receiver or a mobile receiver, but may be, for example, an in-vehicle device mounted in a vehicle, such as an in-vehicle television, or a wearable computer, such as a head-mounted display (HMD).

[0081] In a transmission system to which the present disclosure is applied, a broadcasting system such as an advanced terrestrial broadcasting system can be adopted to provide a broadcast service of 4K content compatible with 4K video. 4K video is video compatible with a screen resolution of approximately 3840 x 2160 pixels. Furthermore, in a transmission system to which the present disclosure is applied, a server having various functions connected to a communication line such as the Internet may be provided, so that a receiving device 20 having communication functions can access the server via the communication line to perform two-way communication and receive and process various data such as content and applications.

[0082] <Computer Configuration> The above-described series of processes can be executed by hardware or software. When the series of processes is executed by software, a program constituting the software is installed in a computer. Fig. 15 is a block diagram showing an example of the hardware configuration of a computer that executes the above-described series of processes by a program.

[0083] In the computer, a CPU (Central Processing Unit) 1001, a ROM (Read Only Memory) 1002, and a RAM (Random Access Memory) 1003 are interconnected by a bus 1004. An input / output interface 1005 is further connected to the bus 1004. An input unit 1006, an output unit 1007, a storage unit 1008, a communication unit 1009, and a drive 1010 are connected to the input / output interface 1005.

[0084] The input unit 1006 includes a keyboard, a mouse, a microphone, etc. The output unit 1007 includes a display, a speaker, etc. The storage unit 1008 includes a hard disk, a non-volatile memory, etc. The communication unit 1009 includes a network interface, etc. The drive 1010 drives a removable recording medium 1011 such as a semiconductor memory, a magnetic disk, an optical disk, or a magneto-optical disk.

[0085] In a computer configured as described above, the CPU 1001 loads a program recorded in the ROM 1002 or memory unit 1008 into the RAM 1003 via the input / output interface 1005 and the bus 1004 and executes it, thereby performing the above-mentioned series of processes.

[0086] The program executed by the computer (CPU 1001) can be provided by being recorded on a removable recording medium 1011 such as a package medium, for example. The program can also be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

[0087] In a computer, the program can be installed in the storage unit 1008 via the input / output interface 1005 by inserting the removable recording medium 1011 into the drive 1010. The program can also be received by the communication unit 1009 via a wired or wireless transmission medium and installed in the storage unit 1008. Alternatively, the program can be installed in advance in the ROM 1002 or the storage unit 1008.

[0088] The processing performed by a computer according to a program includes processing that is executed in parallel or individually (for example, parallel processing or object-based processing). In addition, the program may be processed by a single computer (processor) or may be distributed among multiple computers.

[0089] It should be noted that the embodiments of the present disclosure are not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present disclosure. Furthermore, the effects described in this specification are merely examples and are not intended to be limiting, and other effects may also be obtained.

[0090] The present disclosure can also be configured as follows.

[0091] (1) A transmitting device comprising: a multiplexing unit that multiplexes, by an LDM system, a first signal to be transmitted by a first layer and multiplexed at a first power and a second signal to be transmitted by a second layer and multiplexed at a second power different from the first power; a generating unit that generates control information; and a configuring unit that configures a physical layer frame using the multiplexed signal and the control information, wherein the control information includes information indicating a carrier for each hierarchical layer in the second layer for each subframe included in the physical layer frame. (2) The transmitting device according to (1), in which the second layer has the same configuration as the first layer in terms of the subframes and the hierarchical layers. (3) The transmitting device according to (1), in which the second layer has a different configuration from the first layer in terms of the subframes and the hierarchical layers. (4) The transmitting device according to any of (1) to (3), in which a specific broadcasting service is provided by the first signal and the second signal. (5) The transmitting device according to any one of (1) to (3), wherein the first layer is a UL using the LDM method, the second layer is a LL using the LDM method, the hierarchical layer is a layer having a segment structure in which one channel is divided into segments, the physical layer frame is an OFDM frame, and the information indicating the operator is included in transmission control auxiliary information included in TMCC information. (6) A transmitting method, wherein the transmitting device multiplexes, by LDM, a first signal to be transmitted by the first layer and multiplexed at a first power and a second signal to be transmitted by the second layer and multiplexed at a second power different from the first power, generates control information, and configures a physical layer frame using the multiplexed signal and the control information, and the control information includes information indicating an operator for each hierarchical layer in the second layer for each subframe included in the physical layer frame.(7) A receiving device comprising: a first demodulation unit that demodulates control information included in a physical layer frame transmitted from a transmitting device; and a second demodulation unit that demodulates, based on the demodulated control information, a first signal and a second signal that are multiplexed using an LDM method and are included in the physical layer frame, wherein the first signal is transmitted by a first layer that is multiplexed at a first power using the LDM method, and the second signal is transmitted by a second layer that is multiplexed at a second power different from the first power using the LDM method, and the control information includes information indicating an operator for each hierarchical layer in the second layer for each subframe included in the physical layer frame. (8) The receiving device described in (7), wherein the second layer has the same configuration as the first layer in terms of the subframes and the hierarchical layers. (9) The receiving device described in (7), wherein the second layer has a different configuration from the first layer in terms of the subframes and the hierarchical layers. (10) The receiving device according to any one of (7) to (9), wherein a specific broadcasting service is provided by the first signal and the second signal. (11) The receiving device according to any one of (7) to (9), wherein the first layer is an UL according to the LDM method, the second layer is an LL according to the LDM method, the hierarchy is a hierarchy having a segment structure in which one channel is divided into segments, the physical layer frame is an OFDM frame, and the information indicating the operator is included in transmission control auxiliary information included in TMCC information. (12) A receiving method in which a receiving device demodulates control information included in a physical layer frame transmitted from a transmitting device, and demodulates, based on the demodulated control information, a first signal and a second signal multiplexed using an LDM method included in the physical layer frame, wherein the first signal is transmitted by a first layer in which the first signal is multiplexed at a first power using the LDM method, and the second signal is transmitted by a second layer in which the second signal is multiplexed at a second power different from the first power using the LDM method, and the control information includes, for each subframe included in the physical layer frame, information indicating an operator for each hierarchy in the second layer.

[0092] 10 Transmitting device, 20 Receiving device, 101 UL processing section, 102 LL processing section, 103 LDM multiplexing section, 104 Selection section, 105 Control information generating section, 106 Frame constructing section, 201 Demodulation section, 202 Processing section, 211 Control information demodulation section, 212 UL demodulation section, 213 LL demodulation section

Claims

1. A transmitting device comprising: a multiplexing unit that multiplexes a first signal transmitted by a first layer, the first signal being multiplexed at a first power, and a second signal transmitted by a second layer, the second signal being multiplexed at a second power different from the first power, using an LDM method; a generating unit that generates control information; and a configuration unit that configures a physical layer frame using the multiplexed signal and the control information, wherein the control information includes information indicating an operator for each hierarchical level in the second layer for each subframe included in the physical layer frame.

2. The transmitting device according to claim 1, wherein the second layer has the same subframe and hierarchical configuration as the first layer.

3. The transmitting device according to claim 1, wherein the second layer has a different subframe and hierarchical configuration from the first layer.

4. The transmitting device according to claim 1, wherein a specific broadcasting service is provided by the first signal and the second signal.

5. The transmitting device of claim 1, wherein the first layer is a UL using the LDM method, the second layer is a LL using the LDM method, the hierarchy is a hierarchy consisting of a segment structure in which one channel is divided into segments, the physical layer frame is an OFDM frame, and the information indicating the operator is included in transmission control auxiliary information included in TMCC information.

6. A transmission method in which a transmitting device multiplexes a first signal transmitted by a first layer, the first signal being multiplexed at a first power, and a second signal transmitted by a second layer, the second signal being multiplexed at a second power different from the first power, using an LDM method; generates control information; and configures a physical layer frame using the multiplexed signal and the control information, the control information including, for each subframe included in the physical layer frame, information indicating an operator for each hierarchical level in the second layer.

7. A receiving device comprising: a first demodulation unit that demodulates control information included in a physical layer frame transmitted from a transmitting device; and a second demodulation unit that demodulates a first signal and a second signal multiplexed by an LDM method included in the physical layer frame based on the demodulated control information, wherein the first signal is transmitted by a first layer in which the first signal is multiplexed at a first power according to the LDM method, and the second signal is transmitted by a second layer in which the second signal is multiplexed at a second power different from the first power according to the LDM method, and the control information includes information indicating an operator for each hierarchy in the second layer for each subframe included in the physical layer frame.

8. The receiving device according to claim 7, wherein the second layer has the same subframe and hierarchical configuration as the first layer.

9. The receiving device according to claim 7, wherein the second layer has a different subframe and hierarchical configuration from the first layer.

10. The receiving device according to claim 7, wherein the first signal and the second signal provide a specific broadcast service.

11. The receiving device of claim 7, wherein the first layer is a UL using the LDM method, the second layer is a LL using the LDM method, the hierarchy is a hierarchy consisting of a segment structure in which one channel is divided into segments, the physical layer frame is an OFDM frame, and the information indicating the operator is included in transmission control auxiliary information included in TMCC information.

12. A receiving method, in which a receiving device demodulates control information included in a physical layer frame transmitted from a transmitting device, and demodulates a first signal and a second signal multiplexed using an LDM method included in the physical layer frame based on the demodulated control information, the first signal is transmitted by a first layer in which the first signal is multiplexed at a first power using the LDM method, and the second signal is transmitted by a second layer in which the second signal is multiplexed at a second power different from the first power using the LDM method, and the control information includes information indicating an operator for each hierarchy in the second layer for each subframe included in the physical layer frame.

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