Transmitting device and receiving device

Abstract

To enable preamble signals to be transmitted efficiently and using a highly extendable method in a broadcasting system.SOLUTION: A transmitter 100 to be used in a broadcasting system 1 in which a plurality of bandwidths are specified as a bandwidth corresponding to one channel comprises a preamble signal generation unit 110 for generating a preamble signal. The preamble signal generation unit 110 includes: mapping means (112) for mapping a preamble signal sequence to carriers, the number of which corresponds to one bandwidth to be used for broadcast transmission of the plurality of bandwidths; conversion means (113) for performing conversion from a frequency region to a time region on the preamble signal sequence mapped by the mapping means; and shifting means (117) for performing time shift processing with a shift amount corresponding to control information to be transmitted using the preamble signal on the preamble signal sequence in the time region output by the conversion means.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a transmission device and a reception device used in a broadcast system.

Background Art

[0002] Towards the improvement of quality and functionality of terrestrial digital broadcasting, studies are underway on a transmission method for next-generation terrestrial broadcasting (hereinafter referred to as the "advanced terrestrial broadcasting method") that inherits the features of the current ISDB-T (Integrated Services Digital Broadcasting - Terrestrial) method defined in Non-Patent Document 1 (see, for example, Patent Document 1 and Non-Patent Document 2).

[0003] In ISDB-T, hierarchical transmission enables the simultaneous provision of mobile reception services and fixed reception services on a single channel. Also in the advanced terrestrial broadcasting method, it is assumed that a plurality of services and contents are transmitted within a single channel by hierarchical transmission.

[0004] Here, in ISDB-T, hierarchical transmission based on frequency division multiplexing (FDM) is possible. Specifically, the transmission band of a single channel is divided into 13 segments, and segments are assigned for mobile reception and fixed reception respectively, thereby realizing hierarchical transmission. By setting the mobile reception layer in the central 1 segment, narrowband reception can be performed, which is advantageous in that power-saving reception can be achieved for the receiving device.

[0005] On the one hand, in DVB-T2 and ATSC (Advanced Television Systems Committee) 3.0, which are broadcasting standards in Europe and the United States, hierarchical transmission based on time-division multiplexing (TDM) is possible. Specifically, the hierarchy can be divided into OFDM symbol units to provide a plurality of sub-frames, for example, a sub-frame for mobile reception and a sub-frame for fixed reception (see, for example, Non-Patent Document 3). In the case of TDM, since the FFT (Fast Fourier Transform) size can be changed for each sub-frame, it is possible to set an optimal FFT size according to the service.

[0006] In addition, in a broadcasting system, in addition to the main-line signals such as content, it is necessary to multiplex and transmit control information such as transmission parameters. In ISDB-T based on FDM, specific OFDM sub-carriers are allocated for transmitting control information, and the control information is transmitted in units of frames. In the case of ISDB-T, the TMCC (Transmission and Multiplexing Configuration and Control) signal corresponds to this. On the other hand, in DVB-T2 and ATSC 3.0 based on TDM, the control information is transmitted in several symbols at the beginning of the frame. In ATSC 3.0, the bootstrap and preamble signals correspond to this.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Non-Patent Documents

[0008]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] In the terrestrial broadcast enhancement system, it is required to transmit control information efficiently and in a highly extensible manner. Also, in next-generation terrestrial broadcasting, as the transmission bandwidth, there are two bandwidth modes: the same 5.57 MHz as ISDB-T (compatible mode) and 5.83 MHz with a bandwidth extended by about 5% (normal mode).

[0010] Under such a premise, assume a multiplexing method that introduces a preamble signal by TDM into the terrestrial broadcast enhancement system and arranges the preamble signal at the head of the frame. In this multiplexing method, the receiving device first performs signal detection of the preamble signal.

[0011] Therefore, when two types of bandwidths are provided for the preamble signal, the receiving device also needs to try two types of demodulation methods to determine which bandwidth is used for broadcast transmission. On the other hand, when there is only one type of bandwidth for the preamble signal, it is necessary to transmit the preamble signal in accordance with the narrow bandwidth, which leads to a decrease in frequency utilization efficiency.

[0012] Therefore, an object of the present invention is to provide a transmitting device and a receiving device capable of transmitting a preamble signal efficiently and in a highly extensible manner in a broadcast system.

Means for Solving the Problems

[0013] The transmission device according to the first aspect is a transmission device used in a broadcast system in which a plurality of bandwidths are defined as the bandwidth corresponding to one channel, and includes a preamble signal generation means for generating a preamble signal, and a transmission means for transmitting the preamble signal at the head portion of a frame. The preamble signal generation means includes a mapping means for mapping a preamble signal sequence to a number of carriers corresponding to one bandwidth used for broadcast transmission among the plurality of bandwidths, a conversion means for converting the preamble signal sequence mapped by the mapping means from the frequency domain to the time domain, and a shift means for performing a time shift process of a shift amount corresponding to control information transmitted by the preamble signal on the preamble signal sequence in the time domain output by the conversion means.

[0014] The receiving device according to the second aspect is a receiving device used in a broadcast system in which a plurality of bandwidths are defined as the bandwidth corresponding to one channel, and includes a receiving means for receiving a preamble signal at the head portion of a frame from a transmission device, and a preamble signal processing means for demodulating the preamble signal to acquire control information. The preamble signal processing means specifies the shift amount of the time shift applied to the preamble signal sequence in the time domain, and acquires the control information corresponding to the specified shift amount.

Advantages of the Invention

[0015] According to the present invention, in a broadcast system, it is possible to provide a transmission device and a receiving device capable of transmitting a preamble signal efficiently and in a highly extensible manner.

Brief Description of the Drawings

[0016]

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DETAILED DESCRIPTION OF THE INVENTION

[0017] Embodiments will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0018] (1) Broadcast system First, a broadcast system according to the present embodiment will be described with reference to FIGS. 1 to 3. The broadcast system according to the present embodiment is a system corresponding to the advanced terrestrial broadcast system, and is a terrestrial digital television broadcast system that performs hierarchical transmission.

[0019] (1.1) Transmission band in the broadcast system With reference to FIG. 1, the transmission band in the broadcast system according to the present embodiment will be described. In the present embodiment, it is assumed that the total bandwidth of one channel is 6 MHz.

[0020] As shown in Fig. 1(a), in ISDB-T, the transmission bandwidth (5.57 MHz) of one channel is divided into 13 segments in the frequency direction. Among these, the central segment is set as the partial reception band α for mobile reception services, and the remaining 12 segments are set as the non-partial reception band β for fixed reception services. A receiving device for mobile reception (i.e., a mobile device) can perform power-saving reception by setting the mobile reception layer to the central segment, enabling a narrow-band receiving device to perform power-saving reception.

[0021] Here, the mobile reception layer is a layer to which transmission parameters (e.g., carrier modulation method, coding rate) with higher transmission tolerance than the fixed reception layer are applied. The fixed reception layer is a layer to which transmission parameters with lower transmission tolerance than the mobile reception layer are applied and is a layer for performing higher-quality video transmission than the mobile reception layer. The mobile reception layer may be called the A layer, and the fixed reception layer may be called the B layer. Below, an example corresponding to layer transmission of up to three layers (A layer, B layer, C layer) and capable of setting different transmission parameters for each layer will be described.

[0022] Figs. 1(b) and (c) show the transmission bands of the terrestrial broadcast enhancement method. In the terrestrial broadcast enhancement method, it is being considered to divide the transmission band into a larger number of segments compared to ISDB-T and to more finely adjust the bitrate of each layer. As shown in Fig. 1(b), in the compatibility mode of the terrestrial broadcast enhancement method, the bandwidth of one channel is the same as that of ISDB-T, which is 5.57 MHz. The number of segments in the transmission band is, for example, 33, and the both-end portions of the transmission band are adjustment bands. As shown in Fig. 1(c), in the normal mode of the terrestrial broadcast enhancement method, the transmission bandwidth is expanded compared to ISDB-T, for example, to a transmission bandwidth of 5.83 MHz. The number of segments in the transmission band is, for example, 35. In the compatibility mode and the normal mode, the partial reception band α can be set as the bandwidth of the central 1 to 9 segments, and the rest can be set as the non-partial reception band β.

[0023] As described above, in the terrestrial digital TV advanced system, multiple bandwidths are defined as the bandwidth corresponding to one channel. Also, in the terrestrial digital TV advanced system, it is assumed that hierarchical transmission based on FDM is performed while inheriting the features of ISDB-T. However, FDM has disadvantages compared to TDM. Therefore, the broadcast system according to the present embodiment is a broadcast system capable of supporting both multiplexing methods of TDM and FDM.

[0024] (1.2) Overview of multiplexing method Referring to FIG. 2, the features of TDM and FDM will be described.

[0025] Regarding synchronization performance, in TDM, signal detection in a short time and various synchronizations (frequency synchronization, symbol synchronization, frame synchronization) are possible by a preamble signal at the head of a frame (the head of a signal). On the other hand, in FDM, since a TMCC signal assigned to a specific subcarrier (hereinafter, also simply referred to as a "carrier") is used, at least one frame of signal is required for synchronization. Therefore, it can be said that the synchronization performance regarding initial signal detection is superior in TDM than in FDM. Thus, in the present embodiment, a broadcast system is adopted that takes advantage of the merits of TDM by arranging a preamble signal at the head portion of a frame. Also, in the present embodiment, a broadcast system is adopted in which a TMCC signal is arranged at a time position following the preamble signal, and transmission parameters of subsequent sub-frames and layers are notified to a receiving device by the TMCC signal.

[0026] Regarding the flexibility of signal multiplexing, TDM can select FFT sizes suitable for mobile reception and fixed reception respectively, and has a high degree of freedom in parameters. The FFT size refers to the number of samples of the FFT used in the modulation / demodulation process of an OFDM (Orthogonal Frequency Division Multiplexing) signal. For example, when the FFT size is 8192, it is denoted as 8kFFT. For example, mobile reception can use 8kFFT and fixed reception can use 32kFFT. In contrast, in FDM, the same FFT size (e.g., 16kFFT) needs to be used for both mobile reception and fixed reception. Therefore, it can be said that TDM is superior to FDM in terms of the flexibility of signal multiplexing. Thus, in this embodiment, the frame is divided into a plurality of sub-frames, and the FFT size can be set individually for each sub-frame, so as to adopt a broadcasting method that makes use of the advantages of TDM.

[0027] Regarding power saving, TDM can save power by using a time-division receiver on the receiving device side and turning the RF circuit on / off. In contrast, in FDM, a frequency-division receiver is used on the receiving device side for narrowband reception. Power can be saved by reducing the bandwidth. Therefore, it can be said that the power-saving performance of TDM and FDM is equivalent. In this embodiment, a broadcasting method that can use TDM and FDM in combination is adopted. As a result, time-division reception and frequency-division reception can be used in combination, and further power saving can be achieved.

[0028] Regarding scalability, it is easy to add sub-frames in TDM, and it is easy to introduce signals of new services. In contrast, it is relatively difficult to expand in FDM. Therefore, it can be said that TDM is superior to FDM in terms of scalability. Thus, in this embodiment, a sub-frame for transmitting signals of new services is added to enable the introduction of an expansion frame, so as to adopt a broadcasting method that makes use of the advantages of TDM.

[0029] Regarding the multipath characteristics, since TDM is received by the receiving device in a wideband, it is strong against frequency-selective fading (i.e., the effect of frequency interleaving is high). In contrast, FDM can be received in a wideband in the fixed reception layer, but in the mobile reception layer, it is received in a narrowband, so its resistance becomes weak (i.e., in narrowband reception, the effect of frequency interleaving becomes low). Therefore, regarding the multipath characteristics, it can be said that TDM is superior to FDM.

[0030] Regarding the speed tolerance, at low speeds, in TDM, the signals are intermittent in the time direction, and it is difficult to obtain the effect of time interleaving. However, in FDM, since the signals are continuous in the time direction, the effect of time interleaving is high. Therefore, regarding the speed tolerance at low speeds, it can be said that FDM is superior to TDM. Thus, in this embodiment, for the layer associated with the service assuming low-speed movement, a specific segment can be occupied by setting, and a broadcasting method that makes use of the merits of FDM is adopted. Also, regarding the speed tolerance, at high speeds, TDM can use an FFT size suitable for mobile reception. In FDM, the characteristics depend on the FFT size used.

[0031] As described above, FDM and TDM each have different merits, and the optimal multiplexing method varies according to the required conditions of the service. In this embodiment, in the broadcasting system, a broadcasting method is adopted in which the optimal multiplexing method can be applied according to the required conditions of the service. Specifically, by adopting a broadcasting method in which either the TDM or FDM multiplexing method can be selected, the broadcaster can select the optimal signal multiplexing according to the service.

[0032] Also, in this embodiment, a signal configuration is introduced that can multiplex a plurality of subframes continuously in the time direction like TDM and can perform multiplexing by hierarchical division in units of segments like FDM within each subframe. Also, in this embodiment, it is possible to handle both signal multiplexing like TDM using a plurality of subframes and signal multiplexing like FDM using a plurality of layers in one subframe. Note that a configuration in which only a specific subframe is hierarchically divided by FDM is also possible.

[0033] (1.3) Schematic configuration of the broadcast system With reference to FIG. 3, the schematic configuration of the broadcast system 1 according to the present embodiment will be described. The broadcast system 1 includes a transmission device 100 and a reception device 200. The reception device 200 may include a plurality of types of reception devices 200 including those for fixed reception and those for mobile reception.

[0034] (1.3.1) Schematic configuration of the transmission device The transmission device 100 includes a control signal generation means 101, a hierarchical signal generation means 102, a multiplexing means 103, and a transmission means 104.

[0035] The control signal generation means 101 generates a control signal used for synchronization and control in broadcast transmission and outputs the generated control signal. The control signal generation means 101 includes a preamble signal generation unit 110 that generates a preamble signal among the control signals, and a TMCC signal generation unit 120 that generates a TMCC signal among the control signals. The preamble signal is a signal arranged at the head portion of the frame. The preamble signal is a signal used by the reception device 200 to establish synchronization. The preamble signal is configured to include information necessary for the reception device 200 to receive the TMCC signal. The TMCC signal is a signal following the preamble signal, that is, a signal arranged in a time interval after the head portion of the frame. The TMCC signal is a signal used for control in broadcast transmission and is configured to include TMCC information necessary for the reception device 200 to receive the hierarchical signal.

[0036] The control signal generation means 101 may generate a control signal including information indicating whether partial reception (i.e., narrowband reception) using a partial reception band is enabled. Thereby, it becomes possible to turn on / off partial reception. For example, a partial reception flag is transmitted by the preamble signal. Only the hierarchy within the characteristic subframe can perform intermittent reception and partial reception, which is effective in reducing the power consumption of the receiver.

[0037] The control signal generation means 101 generates a control signal including information indicating the number of sub-frames in a frame and information indicating the number of layers in each sub-frame. For example, a sub-frame can be specified in units of the number of symbols, and a layer can be specified in units of the number of carriers or the number of segments. By including in the control signal the information indicating the number of sub-frames in the frame and the information indicating the number of layers in each sub-frame, the receiving device 200 can appropriately receive the signals of each layer in each sub-frame based on the control signal. The control signal generation means 101 generates a control signal including information indicating the FFT size specified for each sub-frame and information indicating the carrier modulation method and coding rate specified for each layer in each sub-frame. Since the FFT size and the guard interval length can be specified for each sub-frame, it is possible to multiplex signals with different OFDM symbol lengths. Also, for a layer, the carrier modulation method and the coding rate can be variably set while the FFT size and the guard interval length are constant. For example, a TMCC signal includes transmission parameters regarding subsequent signal configurations, such as transmission mode (SISO, MISO, MIMO), number of sub-frames, number of layers in a sub-frame, number of symbols in a sub-frame, number of segments in each layer, modulation order of each layer (carrier modulation method), time interleaving length, coding rate, and other parameters.

[0038] When the control signal generation means 101 provides a sub-frame to be used as an extended frame, it may generate a control signal including information indicating that the sub-frame is an extended frame. This makes it easy to expand the service by taking advantage of the merits of TDM. For example, the length of the extended frame is specified by a preamble signal or a TMCC signal. A receiving device 200 that does not correspond to the signal of the extended frame can receive normal sub-frames while ignoring the extended frame.

[0039] The control signal generation means 101 may generate a control signal including information specifying any one of SISO transmission, MIMO transmission, and MISO transmission for each layer or each sub-frame. Thereby, the transmission mode can be variably set for each layer or each sub-frame.

[0040] The hierarchical signal generation means 102 generates signals of a plurality of hierarchies associated with different services respectively. For example, the services include a mobile reception service and a fixed reception service. The services may include a voice service and a video service. In the present embodiment, it is assumed that the hierarchical signal generation means 102 generates signals of two hierarchies (hierarchy A, hierarchy B) or three hierarchies (hierarchy A, hierarchy B, hierarchy C). The hierarchical signal generation means 102 can set different transmission parameters (for example, carrier modulation method, coding rate) for the signals for each hierarchy.

[0041] The multiplexing means 103 multiplexes the preamble signal generated by the preamble signal generation unit 110, the TMCC signal generated by the TMCC signal generation unit 120, and the signals of a plurality of hierarchies generated by the hierarchical signal generation means 102, and outputs a multiplexed signal. The multiplexing means 103 includes an FDM means 103a that multiplexes signals of two or more hierarchies included in a plurality of hierarchies by FDM within the transmission band of one channel, and a TDM means 103b that multiplexes signals of two or more hierarchies included in a plurality of hierarchies by time division multiplexing within one frame. By the multiplexing means 103 having both the FDM means 103a and the TDM means 103b, the transmission device 100 used in the broadcast system 1 can be compatible with both FDM and TDM, and a broadcaster can apply an optimal multiplexing method according to the service requirement conditions.

[0042] In the present embodiment, the TDM means 103b performs TDM by dividing a frame into a plurality of sub-frames in the time direction. The FDM means 103a performs FDM by dividing the transmission band of a channel into segments of two or more hierarchies in the frequency direction in at least one sub-frame. By dividing a frame into sub-frames in the time direction and dividing each sub-frame into segments of two or more hierarchies in the frequency direction, it becomes possible to combine TDM and FDM. Thereby, efficient broadcast transmission becomes possible by taking advantage of the respective merits of TDM and FDM.

[0043] The TDM means 103b arranges a control signal in the leading time interval (i.e., the frame leading portion) in the frame. By arranging the control signal used for synchronization and control of broadcast transmission in the leading time interval in the frame, the receiving device 200 can establish synchronization early at the frame head.

[0044] The FDM means 103a may arrange a segment of a specific layer (for example, layer A) associated with a mobile reception service within a partial reception band of the transmission band in a sub-frame including the segment of the specific layer. Thereby, even while using TDM, partial reception by FDM such as ISDB-T becomes possible. Also, the FDM means 103a may arrange a TMCC signal associated with a mobile reception service within the partial reception band. Thereby, partial reception of the TMCC signal becomes possible.

[0045] The TDM means 103b may multiplex, by TDM, at least one sub-frame in which signals of a plurality of layers are arranged and a sub-frame used as an extended frame. Thereby, taking advantage of TDM, service expansion becomes easy.

[0046] The transmission means 104 transmits the multiplexed signal multiplexed by the multiplexing means 103 by means of a broadcast wave. The transmission means 104 may perform single-antenna transmission using one transmission antenna, or may perform multi-antenna transmission using two or more transmission antennas. In the present embodiment, it is assumed that the transmission means 104 corresponds to multi-antenna transmission using two transmission antennas. A transmission system associated with one transmission antenna is called "System 1", and a transmission system associated with the other transmission antenna is called "System 2". Therefore, the broadcast system 1 can support various transmission methods such as SISO (Single-Input Single-Output), MISO (Multiple-Input Single-Output), MIMO (Multiple-Input Multiple-Output), SFBC (Space-Frequency Block Code), STBC (Space-Time Block Code), and SDM (Space Division Multiplexing). In STBC, two data symbols are grouped in the time direction, and complex conjugate and code inversion of the data carrier symbols are performed. In SFBC, two data symbols are grouped in the frequency direction, and complex conjugate and code inversion of the data carrier symbols are performed.

[0047] (1.3.2) Schematic Configuration of Receiver The receiver 200 includes a receiving means 201, a control signal processing means 202, a multiplexing separation means 203, and a hierarchical signal processing means 204.

[0048] The receiving means 201 receives a multiplexed signal from the transmitting device 100 by a broadcast wave and outputs a received signal which is the received multiplexed signal. In the multiplexed signal, in the time direction, a preamble signal arranged at the frame head portion, a TMCC signal arranged in a time interval after the preamble signal, and one or a plurality of sub-frame signals arranged after the TMCC signal are multiplexed by TDM. In each sub-frame, in the frequency direction, signals of one or a plurality of layers are multiplexed by FDM. Note that the receiving means 201 may perform single antenna reception using one receiving antenna, or may perform multiple antenna reception using two or more receiving antennas.

[0049] The control signal processing means 202 processes the control signal included in the received signal. The control signal generation means 101 includes a preamble signal processing unit 32 that processes the preamble signal among the control signals, and a TMCC signal processing unit 33 that processes the TMCC signal among the control signals. The preamble signal processing unit 32 establishes synchronization based on the preamble signal. Further, the preamble signal processing unit 32 demodulates the preamble signal, specifies transmission parameters for receiving and processing the TMCC signal based on the information transmitted by the preamble signal, and outputs the specified transmission parameters. The TMCC signal processing unit 33 demodulates and decodes the TMCC signal based on the transmission parameters specified by the preamble signal processing unit 32, specifies transmission parameters for receiving and processing the layer signal based on the TMCC information transmitted by the TMCC signal, and outputs the specified transmission parameters.

[0050] The multi-separation means 203 multiplexes and separates signals of a plurality of layers from a received signal (multi-signal) based on the transmission parameters output by the TMCC signal processing unit 33, and outputs one or more layers of signals associated with the selected service. The multi-separation means 203 includes a TDM separation means 203a that separates signals of layers multiplexed by TDM within one frame, and an FDM separation means 203b that separates signals of layers multiplexed by FDM within the transmission band of one channel. Specifically, the TDM separation means 203a extracts a target sub-frame including signals of the layer associated with the selected service. The FDM separation means 203b acquires the signals of the layer from the target sub-frame extracted by the TDM separation means 203a, and outputs the acquired layer signals.

[0051] The hierarchical signal processing means 204 processes (demodulates and decodes) the hierarchical signals output by the multi-separation means 203 based on the transmission parameters output by the TMCC signal processing unit 33 to obtain hierarchical data (for example, video data), and outputs the obtained hierarchical data.

[0052] (2) An example of the signal configuration With reference to FIGS. 4 to 8, an example of the signal configuration according to the present embodiment will be described.

[0053] (2.1) TDM arrangement, FDM arrangement With reference to FIG. 4, a signal configuration example when TDM arrangement and FDM arrangement are used for the signal configuration of hierarchical signals will be described. FIG. 4(a) shows a signal configuration example when TDM arrangement is used for the signal configuration of hierarchical signals, and FIG. 4(b) shows a signal configuration example when FDM arrangement is used for the signal configuration of hierarchical signals. Note that the bandwidth of the transmission band may be in the normal mode or the compatibility mode.

[0054] As shown in FIG. 4(a), the transmission device 100 arranges a preamble signal, a TMCC signal, and a hierarchical signal by TDM. When the number of sub-frames in a frame is "2" and the number of hierarchies in each sub-frame is "1", the signal configuration is as shown in FIG. 4(a). The frame head portion where the preamble signal is arranged consists of a plurality of symbol intervals (4 symbols in the example of FIG. 4). The time interval where the TMCC signal is arranged is immediately after the preamble signal, and the first symbol interval of the TMCC signal is continuous with the last symbol interval of the preamble signal. In the example of FIG. 4, the time interval where the TMCC signal is arranged consists of two symbol intervals. For example, the sub-frame immediately after the TMCC signal is sub-frame A, and a signal of hierarchy A is arranged in this sub-frame. The sub-frame immediately after sub-frame A is sub-frame B, and a signal of hierarchy B is arranged in this sub-frame. Each of sub-frames A and B consists of a plurality of symbol intervals. When the FFT size and the guard interval length are set differently for sub-frames A and B, the symbol lengths of sub-frames A and B are different from each other. In the example shown in FIG. 4(a), the time length of each symbol interval constituting sub-frame A is shorter than the time length of each symbol interval constituting sub-frame B.

[0055] As shown in FIG. 4(b), even when FDM arrangement is used for the signal configuration of the hierarchical signal, the signal configurations of the preamble signal and the TMCC signal are the same as those in FIG. 4(a). When the number of sub-frames in a frame is "1" and the number of hierarchies in each sub-frame is "2", the signal configuration is as shown in FIG. 4(b). Each hierarchy is composed of one or a plurality of segments. Each hierarchy may be specified in units of segments less than 1 (for example, 1 / 3 segment).

[0056] (2.2) Combination of TDM and FDM Referring to FIG. 5, a signal configuration example when a combination of FDM and TDM is used for the signal configuration of the hierarchical signal will be mainly described with differences from FIG. 4.

[0057] When the number of sub - frames within a frame is set to "2", the number of layers in the first sub - frame A is set to "2", and the number of layers in the other sub - frame B is set to "1", the signal configuration is as shown in FIG. 5. The signal configurations of the preamble signal and the TMCC signal are the same as those in FIG. 4.

[0058] For example, when sub - frame A is assumed to be a layer for mobile reception and sub - frame B is assumed to be a service layer for fixed reception, in layer A of sub - frame A, there is only audio content, and in layer B of sub - frame A, there is only video content, etc. Such a form is effective when only the audio service of mobile reception is desired to have high resistance.

[0059] (2.3) Example of signal configuration when performing partial reception band Referring to FIG. 6, an example of the signal configuration when performing partial reception will be described. When enabling partial reception, the transmitting device 100 notifies the receiving device 200 that partial reception is effective by means of a preamble signal or a TMCC signal.

[0060] When the transmitting device 100 enables partial reception, it performs signal arrangement so that the signals of the layer targeted for partial reception are contained within the partial reception band. Also, the TMCCC signal needs to be contained within the partial reception band for transmission. That is, the transmitting device 100 aggregates the TMCC signal for partial reception within the bandwidth for performing narrow - band reception.

[0061] Regarding the preamble signal, since information is carried in the phase rotation amount (time shift amount) of the preamble signal sequence, even if it is a signal in only a partial reception band, the receiving device 200 can demodulate it as long as a certain required CN is ensured. Therefore, it is not always necessary to change the arrangement of the preamble signal for partial reception. However, since the required CN becomes larger compared to the case of receiving the entire band, a preamble signal that fits within the partial reception bandwidth may be added as necessary. Fig. 6(a) shows a signal configuration in which the preamble signal for partial reception is not aggregated within the bandwidth for narrowband reception, Fig. 6(b) shows a signal configuration in which the preamble signal for partial reception is aggregated within the bandwidth for narrowband reception, and Fig. 6(c) shows a signal configuration in which the preamble signal is arranged only within the bandwidth for narrowband reception.

[0062] (2.4) Frame for extension With reference to Fig. 7, a signal configuration example when a frame for extension is introduced will be described. When introducing a frame for extension, the transmitting device 100 notifies the receiving device 200 that the subframe is a frame for extension based on the TMCC information for each subframe in the TMCC signal. The length of the frame for extension is specified in units of the number of clocks. When the receiving device 200 that does not correspond to the frame for extension receives a notification that it is a frame for extension from TMCC, it ignores the signal during this period.

[0063] (2.5) Frame boundary pilot With reference to Fig. 8, a signal configuration example when a frame boundary pilot is used will be described.

[0064] The transmitting device 100 may arrange frame boundary SPs (Scattered Pilots) for the first symbol and the last symbol in a subframe. The frame boundary SPs may be SPs with a higher pilot density than normal SPs. When a signal is composed of a plurality of subframes, transmission path estimation at the subframe boundary may become complicated. Therefore, by inserting frame boundary SPs, the transmission path estimation accuracy at the frame boundary can be improved. Whether to include frame boundary SPs can be specified by a TMCC signal. Also, the SP arrangement of normal SPs can be specified by a TMCC signal. Parameters related to SPs may be specifiable for each layer within a subframe. Also, by setting the boost ratio of the SPs inserted as frame boundary SPs to 1, the power allocated to data carriers between symbols can be made constant.

[0065] In the signal configuration example shown in FIG. 8, the number of symbols constituting a subframe is "11". The transmitting device 100 notifies the receiving device 200 of the number of symbols "11" constituting the subframe based on the TMCC information for each subframe in the TMCC signal. Also, in the signal configuration example shown in FIG. 8, for normal SPs, the arrangement interval (Dx) in the frequency direction is "3", and the arrangement interval (Dy) in the time direction is "4". For frame boundary SPs, the arrangement interval (Dy) in the time direction is "1".

[0066] (3) An example of a transmitting device With reference to FIG. 9, an example of the transmitting device 100 according to this embodiment will be described.

[0067] The transmission device 100 includes a preamble signal generation unit 110 that generates a preamble signal, a TMCC signal generation unit 120 that generates a TMCC signal, a subframe A configuration unit 130a that constitutes subframe A, a subframe B configuration unit 130b that constitutes subframe B, an extended frame configuration unit 130c that constitutes an extended frame, a TDM frame configuration unit 140 that constitutes a frame, an orthogonal modulation unit 25, and a DAC (digital to analog converter) unit 26. The TDM frame configuration unit 140 constitutes at least a part of the above-described TDM means 103b. The orthogonal modulation unit 25 and the DAC unit 26 constitute at least a part of the above-described transmission means 104. Each unit shown in FIG. 9 may operate in synchronization with the same sampling clock.

[0068] In FIG. 9, two subframe configuration units, i.e., the subframe A configuration unit 130a and the subframe B configuration unit 130b, are illustrated, but three or more subframe configuration units may be provided. Each subframe configuration unit has a similar block configuration. Although an example of providing subframe configuration units individually for each subframe is illustrated, a configuration in which one subframe configuration unit is shared in a time-division manner may also be used. Although an example of using three layers from layer A to layer C is illustrated, a configuration using two layers, i.e., layer A and layer B, may also be used. Although an example of providing two transmission systems, i.e., system 1 and system 2, is illustrated, a configuration with only one system may also be used.

[0069] The subframe A configuration unit 130a includes energy diffusion units 11 (11a, 11b, 11c) provided for each layer, error correction encoding units 12 (12a, 12b, 12c) provided for each layer, carrier modulation units 13 (13a, 13b, 13c) provided for each layer, and system separation units 14 (14a, 14b, 14c) provided for each layer. When there is only one transmission system (for example, when using SISO), the system separation unit 14 is unnecessary. The energy diffusion units 11, the error correction encoding units 12, and the carrier modulation units 13 constitute at least a part of the above-described layer signal generation means 102.

[0070] The energy diffusion unit 11 (11a, 11b, 11c) performs energy diffusion processing on the data of the corresponding layer and outputs the layer data after the energy diffusion processing. The error correction encoding unit 12 (12a, 12b, 12c) performs error correction encoding processing on the data of the corresponding layer and outputs the layer data after the error correction encoding processing in units of FEC (Forward Error Correction) blocks. As the error correction code, an LDPC (Low Density Parity Check) code can be used. The carrier modulation unit 13 (13a, 13b, 13c) performs carrier modulation processing on the data of the corresponding layer, maps the data to a carrier, and outputs the layer data (carrier symbols) after the carrier modulation processing. Hereinafter, the layer data after the carrier modulation processing is referred to as a layer signal. The system separation unit 14 (14a, 14b, 14c) separates the layer signal of the corresponding layer into two systems and outputs it.

[0071] Furthermore, the sub-frame A configuration unit 130a includes a layer synthesis unit 15 (151, 152) provided for each system, a band division unit 16 (161, 162) provided for each system, a time interleaving (IL) unit 17 (171, 172) provided for each system, a frequency IL unit 18 (181, 182) provided for each system, a band synthesis unit 19 (191, 192) provided for each system, a frame configuration unit 20 (201, 202) provided for each system, an IFFT (Inverse Fast Fourier Transform) unit 21 (211, 212) provided for each system, a GI (Guard interval) addition unit 22 (221, 222) provided for each system, a MISO encoding unit 23, and a switching unit 24. The band division unit 16 (161, 162) and the band synthesis unit 19 (191, 192) constitute at least a part of the above-described FDM means 103a.

[0072] The hierarchical synthesis unit 15 (151, 152) performs hierarchical synthesis processing on the hierarchical signals of the corresponding system and outputs the hierarchical signals after the hierarchical synthesis processing. The band division unit 16 (161, 162) divides the hierarchically synthesized signal into each band by performing band division processing and outputs the hierarchical signal after the band division processing. For example, a part of the C hierarchical signal is divided into an adjustment band as necessary. The time interleaving unit 17 (171, 172) performs interleaving processing in the time direction (that is, the symbol arrangement order direction in each carrier) on the band-divided hierarchical signal and outputs the hierarchical signal after time interleaving. The frequency interleaving unit 18 (181, 182) performs interleaving processing in the frequency direction on the hierarchical signal after time interleaving and outputs the hierarchical signal after frequency interleaving. The band synthesis unit 19 (191, 192) synthesizes the signals of each band after frequency interleaving to form a data segment. The frame configuration unit 20 (201, 202) adds a pilot signal (SP) and an Lch signal to the input carrier symbol (data segment) to form an OFDM frame. The IFFT unit 21 (211, 212) performs IFFT processing on the OFDM frame to generate a valid symbol signal. The GI addition unit 22 (221, 222) adds a GI, which is a signal obtained by copying a part of the end of the valid symbol signal, to the head of the valid symbol signal output by the IFFT unit 27. Note that the GI is set so that the delay time of the multipath delay wave does not exceed the GI length. Note that the frame configuration unit 20, the IFFT unit 21, and the GI addition unit 22 constitute an OFDM modulation unit. The MISO encoding unit 23 performs space-time encoding (STBC encoding or SFBC encoding) on the signal of one system to generate a signal of two systems. The switching unit 24 selects the output from the two-system band synthesis unit 192 in the case of space division multiplexing (SDM) by MIMO, and selects the output from the MISO encoding unit 23 in the case of MISO and outputs it to the frame configuration unit 202. This switching is linked to the processing of the system separation unit 14.

[0073] The TDM frame composing unit 140 (1401, 1402) multiplexes the preamble signal output by the preamble signal generation unit 110, the TMCC signal output by the TMCC signal generation unit 120, the sub-frame A signal output by the sub-frame A composing unit 130a, the sub-frame B signal output by the sub-frame B composing unit 130b, and the extended frame signal output by the extended frame composing unit 130c into one frame by TDM and outputs a multiplexed signal.

[0074] The quadrature modulation units 25 (251, 252) quadrature-modulate the signal output by the TDM frame composing unit 140 (1401, 1402) and output it to the DAC unit 26. The DAC units 26 (261, 262) perform digital / analog conversion processing on the quadrature-modulated signal and output it as an IF signal. The IF signal output is output from different antennas (transmission systems) after predetermined modulation processing.

[0075] (4) Preamble signal With reference to FIGS. 10 to 16, the preamble signal according to the present embodiment will be described.

[0076] (4.1) Configuration example of preamble signal generation unit With reference to FIG. 10, a configuration example of the preamble signal generation unit 110 according to the present embodiment will be described.

[0077] The preamble signal generation unit 110 includes a sequence generation unit 111, a mapping unit 112, a conversion unit 113, a control information generation unit 114, a relative cyclic shift unit 115, an absolute cyclic shift unit 116, a cyclic shift unit 117, and a CP addition unit 118.

[0078] The sequence generation unit 111 modulates a ZC (Zadoff-Chu) sequence corresponding to Root with a pseudo-noise (PN) sequence corresponding to Seed to generate a preamble signal sequence in the frequency domain. Let the length (N ZC ) of the ZC sequence be 1889. N ZC corresponds to the number of carriers in the frequency domain. The ZC sequence z q(k) can be expressed as follows.

[0079] [Number] However, q is set to 137, and k = 0, 1, 2, …, N ZC is -1.

[0080] The mapping unit 112 maps the preamble signal sequence to a number of carriers corresponding to one bandwidth used for broadcast transmission among a plurality of bandwidths. For example, the bandwidth Bw is 5.830 MHz in the normal mode and 5.571 MHz in the compatibility mode. Thus, on the premise that the normal mode bandwidth (the first bandwidth) and the compatibility mode bandwidth (the second bandwidth) that is narrower than this are defined, when the bandwidth used for broadcast transmission is the second bandwidth, the mapping unit 112 maps zeros to a predetermined number of carriers at both ends of the first bandwidth. That is, the mapping unit 112 generates a signal as the compatibility mode by setting the amplitude value of the sub-carriers that do not stand (at the band edge) of the carriers to "0" for the OFDM signal in the frequency domain in the compatibility mode.

[0081] The conversion unit 113 converts the preamble signal sequence mapped by the mapping unit 112 from the frequency domain to the time domain OFDM signal by IFFT. The FFT size N FFT is set to 2048. The sampling frequency fs (= 512 / 81) is 6.3209 MHz, and the carrier interval f Δ (= fs / N FFT ) is 3.0864 kHz, and the symbol length Ts is 486 μs.

[0082] The control information generation unit 114 generates control information transmitted by the preamble signal. The control information transmitted by the preamble signal includes transmission parameters related to the TMCC signal. Details of the information transmitted by the preamble signal will be described later.

[0083] The relative cyclic shift unit 115 performs relative cyclic shift processing on each symbol constituting the preamble signal with respect to the previous symbol. The absolute cyclic shift unit 116 performs predetermined cyclic shift processing on each symbol constituting the preamble signal.

[0084] The cyclic shift unit 117 performs time shift processing of a shift amount according to the control information output by the absolute cyclic shift unit 116 on the preamble signal sequence in the time domain output by the conversion unit 113. That is, the cyclic shift unit 117 adds phase rotation corresponding to the control information to be transmitted to the time samples (known OFDM signals) after IFFT to obtain the OFDM signal to be transmitted. The phase rotation amount can be transmitted up to 11 bits from 0 to 2048, but considering the detection error, transmission of about 8 bits is realistic. Also, the first symbol (preamble symbol #0) of the preamble signal is a known symbol not multiplied by control information, and control information is transmitted after the second symbol (preamble symbol #1).

[0085] In this way, since the control information is carried on the shift amount (phase rotation amount), which indicates how much the OFDM signal of the transmission signal is shifted on the time axis with respect to the known OFDM signal, the OFDM signal can be generated in the same procedure as in the normal mode even in the compatibility mode. Also, regardless of the transmission bandwidth, that is, regardless of whether it is the normal mode or the compatibility mode, the receiving device 200 can demodulate the preamble signal with the same processing. Therefore, the preamble signal can be transmitted efficiently and in a highly extensible manner.

[0086] The CP addition unit 118 adds a CP, which is a signal obtained by copying a part of the end of the valid symbol signal, to the head of the OFDM signal (valid symbol signal) output by the cyclic shift unit 117. As a result, the preamble signal is generated.

[0087] In the preamble signal generation unit 110 configured as described above, the control information generation unit 114 generates control information including information indicating one bandwidth used for broadcast transmission among a plurality of specified bandwidths. Thereby, the receiving apparatus 200 can identify the normal mode and the compatibility mode by demodulating the preamble signal. Further, the control information generation unit 114 generates control information including information indicating whether partial reception using a predetermined partial reception band is enabled. Thereby, the receiving apparatus 200 can identify partial reception by demodulating the preamble signal.

[0088] (4.2) Operation example of preamble signal generation unit With reference to FIG. 11, an operation example of the preamble signal generation unit 110 according to the present embodiment will be described.

[0089] (4.2.1) Operation example of preamble signal generation unit in compatibility mode FIG. 11(a) shows an operation when the preamble signal is made to correspond to the compatibility mode. As shown in FIG. 11(a), the preamble signal generation unit 110 generates a modulation signal in the compatibility mode in the same procedure as in the normal mode. For example, the same q and N ZC as in the normal mode are used. However, in order to correspond to the bandwidth of the compatibility mode, the mapping unit 112 fills "0" at both ends where there is no carrier in the compatibility mode. In FIG. 11(a), an example is shown in which "0" is assigned to 42 carriers at both ends out of 1889 carriers constituting the bandwidth of the normal mode. On the receiving side (specifically, the preamble signal processing unit 32), the correlation with the known signal is calculated while changing the phase with the time-sampled signal to obtain a peak, but detection can be performed by the same detection method in both the compatibility mode and the normal mode. However, in the case of the compatibility mode, since the information at both ends of the spectrum is missing, an error may occur when the time signal is generated.

[0090] (4.2.2) Operation example of preamble signal generation unit in partial reception band As described above, even if the preamble signal is a signal in only a partial reception band, the receiving apparatus 200 can demodulate it as long as a certain required CN is ensured. Therefore, it is not always necessary to change the signal for partial reception. However, since the required CN becomes larger compared to the case of receiving the entire band, a preamble signal that fits within the partial reception bandwidth may be added as necessary.

[0091] Fig. 11(b) shows the operation when generating a preamble signal for the partial reception band. As shown in Fig. 11(b), when arranging the preamble signal within the partial reception band, the mapping unit 112 maps the preamble signal sequence to a number of carriers corresponding to the bandwidth of the partial reception band. Thereby, a preamble signal corresponding to the partial reception bandwidth can be generated. Specifically, the mapping unit 112 uses a value ZC smaller than the normal value as N which is the number of carriers. Here, it is assumed that the bandwidth of the partial reception band is 1.5 MHz which is 1 / 4 of the normal value. In this case, the number of carriers also needs to be 1 / 4 (512 = 2048 / 4). Therefore, by selecting a number of 512 or less as N which is the number of carriers, the preamble signal can be contained within the partial reception band. ZC

[0092] Fig. 11(c) shows the operation when repeatedly arranging the preamble signal for the partial reception band in the frequency direction. As shown in Fig. 11(c), the mapping unit 112 repeatedly arranges the preamble for the partial reception band even outside the partial reception band. That is, the preamble signal generation unit 110 arranges the preamble signal in the partial reception band and repeatedly arranges the preamble signal in the non-partial reception band. Thereby, the tolerance can be improved for the receiving apparatus 200 that receives the entire band.

[0093] (4.3) An example of control information transmitted by the preamble signal Referring to FIGS. 12 to 16, an example of control information transmitted by a preamble signal will be described. Here, an example in which the preamble symbol is composed of 6 symbols is shown. The first preamble symbol (preamble symbol #0) contains only synchronization information, and the remaining 5 symbols (preamble symbols #1 to #5) transmit the bits of the control information. It is assumed that the number of bits of the control information per symbol is 8 bits.

[0094] FIG. 12 shows an example of control information transmitted by preamble symbol #1. As shown in FIG. 12, the control information transmitted by preamble symbol #1 consists of 2 bits of "system identification", 2 bits of "transmission band identification", 1 bit of "partial reception flag", 2 bits of "emergency warning", and 1 bit of "reservation". The receiving device 200 (preamble signal processing unit 32) can identify the normal mode and the compatible mode by reading the transmission band identification. Also, the receiving device 200 (preamble signal processing unit 32) can detect whether it is in a format corresponding to partial reception by reading the partial reception flag.

[0095] FIG. 13 shows an example of control information transmitted by preamble symbol #2. As shown in FIG. 13, the control information transmitted by preamble symbol #2 consists of 2 bits of "TMCC FFT size (i.e., the FFT size applied to the TMCC signal)", 3 bits of "TMCC GI ratio (i.e., the GI ratio applied to the TMCC signal)", and 3 bits of "TMCC SISO / MISO (i.e., the transmission method applied to the TMCC signal)". By transmitting such transmission parameters of the TMCC signal by the preamble signal, the transmission tolerance of the TMCC signal can also be flexibly set according to the transmission parameters of the main line system (subframe).

[0096] FIG. 14 shows an example of control information transmitted by preamble symbol #3. As shown in FIG. 14, the control information transmitted by preamble symbol #3 consists of 2 bits of "TMCC carrier modulation (i.e., the carrier modulation method applied to the TMCC signal)" and 6 bits of "TMCC page number". The TMCC page number refers to the number of FEC blocks (error correction code blocks) required to transmit TMCC information once. Details of the TMCC page number will be described later.

[0097] FIG. 15 shows an example of control information transmitted by preamble symbol #4. As shown in FIG. 15, the control information transmitted by preamble symbol #4 consists of 4 bits of "TMCC code repetition count (i.e., the number of repetitions of the TMCC FEC block)", 3 bits of "TMCC SP (i.e., the SP arrangement applied to the TMCC signal)", and 1 bit of "TMCC SP coding (i.e., the coding method applied to the SP of the TMCC signal)".

[0098] FIG. 16 shows an example of control information transmitted by preamble symbol #5. As shown in FIG. 16, the control information transmitted by preamble symbol #5 consists of 5 bits of "next frame (time range until the next preamble signal)" and 3 bits of "reserve". The "next frame" is used as auxiliary information for the receiving device 200 (preamble signal processing unit 32) to demodulate the TMCC signal.

[0099] (5) TMCC signal The TMCC signal according to this embodiment will be described with reference to FIGS. 17 to 26.

[0100] (5.1) Configuration example of TMCC signal generation unit With reference to FIG. 17, a configuration example of the TMCC signal generation unit 120 according to this embodiment will be described.

[0101] The TMCC signal generation unit 120 has a TMCC information generation unit 120a, an energy dispersal unit 121, an error correction coding unit 122, a repetition coding unit 123, a carrier modulation unit 124, a phase rotation unit 125, a frequency IL unit 126, a pilot insertion unit 127, an IFFT unit 128, and a GI addition unit 129.

[0102] The TMCC information generator 120a generates TMCC information with a variable number of bits depending on the number of subframes in a frame and the number of layers in each subframe. As described above, there is a large difference in the TMCC information transmitted by the TMCC signal between a case where multiple subframes and multiple layers are transmitted and a case where a single subframe and single layer are transmitted. By making the number of bits of the TMCC information variable depending on the number of subframes in a frame and the number of layers in each subframe, it becomes possible to transmit the TMCC signal efficiently and in a highly scalable manner.

[0103] The energy diffusion unit 121 performs energy diffusion processing on the TMCC information output by the TMCC information generation unit 120a and outputs the TMCC information after the energy diffusion processing. The error correction encoding unit 122 performs error correction encoding processing (specifically, LDPC encoding processing) on the TMCC information after the energy diffusion processing and outputs an FEC block. The iterative encoding unit 123 performs iterative encoding processing on the FEC block output by the error correction encoding unit 122 and outputs the FEC block after the iterative encoding processing. The carrier modulation unit 124 generates a TMCC carrier signal by performing carrier modulation processing on the FEC block after the iterative encoding processing. Although BPSK or QPSK is assumed for the carrier modulation method of the TMCC signal, multi-value modulation such as 16QAM or 64QAM can also be used. The phase rotation unit 125 applies phase rotation so that the mapping to the same signal point in the TMCC carrier signal is not continuous. When using BPSK or QPSK, in order to prevent signals from being continuously arranged at the same signal point (constellation point), known phase rotation is added. Here, the rotation amount is 17Π / 128×k (k is the data carrier number). The frequency IL unit 126 performs frequency IL processing on the TMCC carrier signal. The pilot insertion unit 127 inserts a pilot (SP) into the TMCC carrier signal after the frequency IL processing. The IFFT unit 128 generates a time-domain OFDM signal by performing IFFT processing on the TMCC carrier signal after the pilot insertion. The GI addition unit 129 adds GI to the OFDM signal output by the IFFT unit 128 and outputs a TMCC signal.

[0104] (5.2) Operation example of the TMCC signal generation unit With reference to FIG. 18, an operation example of the TMCC information generation unit 120a according to the present embodiment will be described.

[0105] The TMCC information generation unit 120a constructs TMCC information from three information blocks: "frame", "sub-frame", and "layer". Specifically, the TMCC information generation unit 120a generates TMCC information composed of one frame information block, one or more sub-frame information blocks individually provided for each sub-frame within the frame, and one or more layer information blocks individually provided for each layer within the sub-frame. In FIG. 18, an example is shown where the "frame" information block is 16 bits, the "sub-frame" information block is 32 bits, and the "layer" information block is 56 bits.

[0106] For example, as shown in FIG. 18(a), when the hierarchical signal is configured with a single sub-frame and a single layer, the TMCC information generation unit 120a concatenates one information block each of "frame", "sub-frame", and "layer" to form a total of 104-bit TMCC information. As shown in FIG. 18(b), when the TMCC information generation unit 120a has two sub-frames and each sub-frame is configured with one layer, two "sub-frame" information blocks and two "layer" information blocks are transmitted (a total of 192 bits). As shown in FIG. 18(c), when the TMCC information generation unit 120a is configured with one sub-frame and two layers, one information block each of "frame" and "sub-frame" is used, and two "layer" information blocks are concatenated to generate TMCC information (a total of 160 bits). Therefore, the TMCC information can have a variable length according to the number of sub-frames and the number of layers.

[0107] Referring to FIG. 19, an operation example of the error correction coding unit 122 according to the present embodiment will be described.

[0108] Although the upper limit of the information bits that can be stored in the FEC block is fixed, since the number of bits of the TMCC information is variable, the number of bits of the TMCC information stored in the FEC block may exceed the upper limit of the FEC block. When the number of bits of the TMCC information exceeds the upper limit of the information bits that can be stored in one FEC block, the error correction encoding unit 122 allocates the TMCC information across two or more FEC blocks. For example, when the LDPC code (1224, 256) is used as the error correction code and the number of bits of the TMCC information is larger than the upper limit of the information bits of the FEC block, which is 256 bits, the error correction encoding unit 122 increases the number of pages (i.e., the number of FEC blocks), allocates the TMCC information to multiple FEC blocks, and pads the insufficient part with zeros. An example with one page is shown in FIG. 19(a), and an example with two pages is shown in FIG. 19(b). This enables the appropriate transmission of the TMCC information even when the number of bits of the TMCC information is large.

[0109] Referring to FIG. 20, an operation example of the iterative encoding unit 123 according to the present embodiment will be described.

[0110] In order to improve the transmission tolerance, the iterative encoding unit 123 performs an iterative encoding process of repeatedly arranging the FEC blocks output by the error correction encoding unit 122 (see FIG. 20(a)). FIG. 20(b) shows an example in which one FEC block including information bits and parity bits is repeatedly arranged four times. As described above, this number of iterations is transmitted by the preamble signal. The repeated FEC blocks are transmitted with the number of symbols required for the repetition.

[0111] Referring to FIG. 21, the relationship between the number of iterations and the number of symbols due to the difference in the number of pages will be described.

[0112] When using (1224, 256) for the error correction code, as shown in Fig. 21(a), for the TMCC information with the configuration as shown, as shown in Fig. 21(b), the number of bits of the TMCC information increases according to the increase in the number of sub-frames. When the number of sub-frames becomes 3, 2 pages are required. As shown in Fig. 21(c), in either the case where the number of pages is "1" or the case where the number of pages is "2", the required number of symbols increases according to the increase in the number of iterations.

[0113] Referring to Figs. 22 and 23, an example of information allocation of the TMCC signal in the case of partial reception will be described.

[0114] The receiving device 200 that performs narrowband reception needs to receive only the partial reception band and perform signal detection. As shown in Fig. 22, in order to accurately synchronize the FEC block in the TMCC, the TMCC signal generation unit 120 starts the allocation from the segment in the partial reception band when allocating the FEC block. That is, the TMCC signal generation unit 120 allocates the TMCC signal so that the start of the segment at the end of the partial reception band coincides with the start of the FEC block of the TMCC information. Thereby, the receiving device 200 that performs narrowband reception can perform demodulation from the leading symbol in the partial reception band. Also, as shown in Fig. 23, the TMCC signal generation unit 120 can also preferentially allocate from the symbols in the partial reception band. Specifically, the TMCC signal generation unit 120 starts the allocation of the FEC block from one end segment in the partial reception band at symbol #0 within the time interval where the TMCC signal is arranged. When reaching the middle of the FEC block at the other end in the partial reception band, it wraps around to symbol #1 within the time interval where the TMCC signal is arranged and arranges the rest of the FEC block. Thereby, it becomes even easier for the receiving device 200 that performs narrowband reception to demodulate the TMCC signal.

[0115] (5.3) An example of TMCC information transmitted by the TMCC signal Referring to Figs. 24 to 26, an example of TMCC information transmitted by the TMCC signal according to this embodiment will be described.

[0116] FIG. 24 shows the information included in the "frame" information block of the TMCC information. As shown in FIG. 24, the 16-bit "frame" information block consists of 1 bit of "update flag", 5 bits of "parameter switching index", 6 bits of "number of sub-frames", and 4 bits of "reservation". Here, the "update flag" is information indicating whether the TMCC information has been updated. The "parameter switching index" is information on the countdown of switching from a predetermined number of frames before switching to the next information when a change occurs in the transmission parameters, and new transmission parameters are set as the next information. The "number of sub-frames" is information indicating the number of sub-frames included in the frame. In FIG. 24, an example is shown where the number of sub-frames included in one frame is 1 or 2, but it may also be possible to support 3 or more sub-frame numbers.

[0117] FIG. 25 shows the information included in the "sub-frame" information block of the TMCC information. As shown in FIG. 25, the 32-bit "sub-frame" information block includes information on the transmission parameters of the corresponding sub-frame. Specifically, the "sub-frame" information block consists of 2 bits of "FFT size", 3 bits of "GI ratio", 11 bits of "number of symbols", 6 bits of "number of layers", 3 bits of "transmission mode (SISO / MISO / MIMO)", and 7 bits of "reservation". Each of the "FFT size" and the "GI ratio" can be selected from a plurality of candidates. Thereby, the "FFT size" and the "GI ratio" can be made variable for each sub-frame. The "number of symbols" indicates the number of symbols in the sub-frame, and the "number of layers" indicates the number of layers in the sub-frame. In FIG. 25, an example is shown where the number of layers included in one sub-frame is 1, but it may also be possible to support 2 or more layer numbers. The "transmission mode (SISO / MISO / MIMO)" indicates the transmission mode applied to the sub-frame.

[0118] Figure 26 shows the information included in the "Hierarchy" information block of the TMCC information. As shown in Figure 26, the 56-bit "Hierarchy" information block contains information on the transmission parameters of the corresponding layer. Specifically, the "Hierarchy" information block consists of 7 bits for "Number of Segments", 3 bits for "Carrier Modulation", 1 bit for "UC / NUC", 2 bits for "Code Length", 4 bits for "Coding Rate", 4 bits for "SP Arrangement", 1 bit for "SP Coding", 1 bit for "Frame Boundary SP (Beginning)", 1 bit for "Frame Boundary SP (End)", 1 bit for "All-Carrier Pilot", 3 bits for "SP Level", 3 bits for "Time IL", 18 bits for "FEC Pointer", 3 bits for "Data Carrier Boost", and 4 bits for "Reserved". Here, the "Number of Segments" is information indicating the number of segments that make up the layer, and it can be specified in units of 1 / 3 segments. "Carrier Modulation" indicates the carrier modulation method applied to the layer. "UC / NUC" indicates whether the constellation (I-Q constellation) applied to the layer is uniform (UC) or non-uniform (NUC). "Code Length" indicates whether the error correction code length applied to the layer is short, middle, or long. "Coding Rate" indicates the coding rate of error correction applied to the layer. "SP Arrangement" indicates the arrangement pattern of the SP applied to the layer. "SP Coding" indicates whether the code inversion method or the null method is applied to the SP. "Frame Boundary SP (Beginning)" indicates whether the frame boundary SP (beginning) is applied to the layer, and "Frame Boundary SP (End)" indicates whether the frame boundary SP (end) is applied to the layer. "All-Carrier Pilot" indicates whether the all-carrier pilot is applied to the layer. "SP Level" indicates the SP level applied to the layer. "Time IL" indicates the time interleaving length applied to the layer. "FEC Pointer" indicates the FEC block pointer applied to the layer. "Data Carrier Boost" indicates the power boost ratio applied to the layer.

[0119] (6) An example of a receiving device Referring to FIG. 27, an example of the receiving apparatus 200 according to the present embodiment will be described.

[0120] The receiving apparatus 200 includes a receiving unit 31, a preamble signal processing unit 32, a TMCC signal processing unit 33, a target subframe extraction unit 34, an FFT unit 35, a propagation path estimation unit 36, an equalization unit 37, a hierarchical separation unit 38, and a hierarchical signal processing means 204. The receiving unit 31 corresponds to the above-described receiving means 201. The preamble signal processing unit 32 and the TMCC signal processing unit 33 constitute the above-described control signal processing means 202. The target subframe extraction unit 34 constitutes the above-described TDM separation means 203a. The hierarchical separation unit 38 constitutes the above-described FDM separation means 203b.

[0121] The receiving unit 31 receives a signal in which a preamble signal, a TMCC signal, and a subframe signal are multiplexed by TDM, and outputs the received signal. Note that the receiving unit 31 includes an ADC (analog to digital converter) unit, a quadrature demodulation unit, and the like. The preamble signal processing unit 32 demodulates the preamble signal to obtain control information. Specifically, the preamble signal processing unit 32 identifies the shift amount of the time shift applied to the preamble signal sequence in the time domain, and obtains the control information corresponding to the identified shift amount. The TMCC signal processing unit 33 processes (demodulates and decodes) the TMCC signal based on the control information obtained by the preamble signal processing unit 32. The TMCC signal processing unit 33 obtains TMCC information with a variable number of bits according to the number of subframes in the frame and the number of layers in each subframe. The target subframe extraction unit 34 extracts the subframe signal (OFDM signal) of the target subframe based on the TMCC information obtained by the TMCC signal processing unit 33. The FFT unit 35 performs FFT processing on the OFDM signal from which the GI has been removed, and converts it into a hierarchical signal in the frequency domain. The propagation path estimation unit 36 performs propagation path estimation based on the arranged SPs, and outputs the propagation path estimation result to the equalization unit 37. The equalization unit 37 performs equalization processing on the hierarchical signal using the propagation path estimation result, and estimates the original carrier symbol. The hierarchical separation unit 38 hierarchically separates the hierarchically combined hierarchical signal into carrier symbols of layer A, layer B, and layer C based on the TMCC information obtained by the TMCC signal processing unit 33, and outputs them.

[0122] The hierarchical signal processing means 204 includes a frequency de-interleave (DIL) section 39 (39a, 39b, 39c) provided for each layer, a time DIL section 40 (40a, 40b, 40c) provided for each layer, an LLR calculation section 41 (41a, 41b, 41c) provided for each layer, an error correction decoding section 42 (42a, 42b, 42c) provided for each layer, and an energy de-spreading section 43 (43a, 43b, 43c) provided for each layer. The frequency DIL section 39 (39a, 39b, 39c) performs de-interleaving in the carrier frequency direction for the carrier symbols of the corresponding layer. The time DIL section 40 (40a, 40b, 40c) performs de-interleaving in the time direction for the frequency de-interleaved carrier symbols and returns them to the original array before interleaving is performed on the transmission side. The LLR calculation section 41 (41a, 41b, 41c) calculates the LLR (Log Likelihood Ratio) of the carrier symbols of the corresponding layer. The error correction decoding section 42 (42a, 42b, 42c) performs error correction decoding processing based on the LLR. The energy de-spreading section 43 (43a, 43b, 43c) performs energy de-spreading processing on the hierarchical signal after error correction decoding processing and outputs it.

[0123] (7) Other Embodiments The above-described preamble signal may be a signal arranged at the frame head portion or a signal used for synchronization, and signals having the same configuration and function are included in the preamble signal. Therefore, other names such as a synchronization signal may be used. Also, the above-described TMCC signal may be a signal used for control (various settings) in broadcast transmission, and signals having the same configuration and function are included in the TMCC signal. Therefore, other names such as a control signal or a setting signal may be used.

[0124] A program may be provided that causes a computer to execute each process performed by each of the above-described devices (transmission device 100, reception device 200). The program may be recorded on a computer-readable medium. By using a computer-readable medium, it is possible to install the program on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM. Further, circuits that execute each process performed by each of the above-described devices (transmission device 100, reception device 200) may be integrated, and the device may be configured by a semiconductor integrated circuit (chipset, SoC).

[0125] As described above, the embodiments have been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the gist.

Explanation of Signs

[0126] 1: Broadcasting system 11: Energy diffusion unit 12: Error correction coding unit 13: Carrier modulation unit 14: System separation unit 15: Hierarchical synthesis unit 16: Band division unit 17: Time IL unit 18: Frequency IL unit 19: Band synthesis unit 20: Frame configuration unit 21: IFFT unit 22: GI addition unit 23: MISO coding unit 24: Switching unit 25: Orthogonal modulation unit 26: DAC unit 27: IFFT unit 31: Reception unit 32: Preamble signal processing unit 33: TMCC signal processing unit 34: Target sub-frame extraction section 35: FFT section 36: Propagation path estimation section 37: Equalization section 38: Hierarchical separation section 39: Frequency DIL section 40: Time DIL section 41: LLR calculation section 42: Error correction decoding section 43: Energy despreading section 100: Transmitter 101: Control signal generation means 102: Hierarchical signal generation means 103: Multiplexing means 103a: FDM means 103b: TDM means 104: Transmission means 110: Preamble signal generation section 111: Sequence generation section 112: Mapping section 113: Conversion section 114: Control information generation section 115: Relative cyclic shift section 116: Absolute cyclic shift section 117: Cyclic shift section 118: CP addition section 120: TMCC signal generation section 120a: TMCC information generation section 121: Energy spreading section 122: Error correction encoding section 123: Iterative encoding section 124: Carrier modulation section 125: Phase rotation section 126: Frequency IL section 127: Pilot insertion section 128: IFFT section 129: GI addition section 130a: Sub-frame A construction section 130b: Sub-frame B construction section 130c: Extended frame construction section 140: TDM Frame Component 200: Receiver 201: Receiving Means 202: Control Signal Processing Means 203: Multiplexing Separation Means 203a: TDM Separation Means 203b: FDM Separation Means 204: Hierarchical Signal Processing Means

Claims

1. A transmission device used in a broadcast system, comprising: preamble signal generation means for generating a preamble signal; transmission means for transmitting the preamble signal at the head portion of a frame, the broadcast system includes a first mode having a first bandwidth and a second mode having a second bandwidth narrower than the first bandwidth as the transmission bandwidth of one channel, the preamble signal generation means includes: mapping means for mapping a preamble signal sequence to a number of carriers corresponding to the first bandwidth in the case of the first mode and mapping a preamble signal sequence to a number of carriers corresponding to the second bandwidth in the case of the second mode; conversion means for converting the preamble signal sequence mapped by the mapping means from the frequency domain to the time domain; shift means for performing a time shift process of a shift amount corresponding to control information transmitted by the preamble signal on the preamble signal sequence in the time domain output by the conversion means. The transmission device is characterized by having the above.

2. The transmission device according to claim 1, wherein the control information includes information indicating one bandwidth used for broadcast transmission among the first and second bandwidths.

3. The mapping means maps zeros to a predetermined number of carriers at both ends of the first bandwidth when one bandwidth used for broadcast transmission is the second bandwidth. The transmission device according to claim 1 or 2 is characterized by this.

4. The transmission device according to any one of claims 1 to 3, wherein the control information includes information indicating whether partial reception using a predetermined partial reception bandwidth is enabled.

5. The first and second bandwidths include the bandwidth of a partial reception bandwidth that is a part of the entire bandwidth of one channel, When arranging the preamble signal within the partial reception band, the mapping means maps the preamble signal sequence to a number of carriers corresponding to the bandwidth of the partial reception band. The transmission device according to any one of claims 1 to 4, characterized in that.

6. The preamble signal generation means arranges the preamble signal in the partial reception band and repeatedly arranges the preamble signal in the non-partial reception band. The transmission device according to claim 4 or 5, characterized in that.

7. A receiving device used in a broadcast system, Receiving means for receiving a preamble signal at the head portion of a frame from a transmission device; Preamble signal processing means for demodulating the preamble signal to obtain control information, comprising: The broadcast system includes a first mode having a first bandwidth and a second mode having a second bandwidth narrower than the first bandwidth as the transmission bandwidth of one channel. The preamble signal received from the transmission device is a signal mapped to a number of carriers corresponding to the first bandwidth in the case of the first mode, and a signal mapped to a number of carriers corresponding to the second bandwidth in the case of the second mode. The preamble signal processing means specifies the shift amount of the time shift applied to the preamble signal sequence in the time domain in both the first mode and the second mode, and obtains the control information corresponding to the specified shift amount. The receiving device is characterized by that.

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