Transmitting device and receiving device

Abstract

To provide a broadcasting system capable of applying an optimum multiplexing method according to a service requirement condition.SOLUTION: A transmitter 100 to be used in a broadcasting system 1 for performing hierarchical transfer comprises: multiplexing means 103 for multiplexing signals in a plurality of layers associated with different services, respectively; and transmission means 104 for transmitting multiplex signals multiplexed by the multiplexing means 103. The multiplexing means 103 includes: FDM means 103a for multiplexing signals in two or more hierarchies of the plurality of layers using FDM in a transmission band of one channel; and TDM means 103b for multiplexing signals in two or more hierarchies of the plurality of layers using time division multiplexing in one frame.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Towards the improvement of quality and functionality of terrestrial digital broadcasting, a study of 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 is underway (see, for example, Patent Document 1 and Non-Patent Document 2).

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

[0004] Here, in ISDB-T, hierarchical transmission based on frequency division multiplexing (FDM) is possible. Specifically, the transmission band of one channel is divided into 13 segments, and segments are respectively assigned for mobile reception and fixed reception, thereby realizing hierarchical transmission. By setting the mobile reception layer in the central one segment, narrow-band 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 the first few symbols 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] As described above, the conventional broadcast system was a system based on either FDM or TDM as a multiplexing method. However, FDM and TDM each have different advantages, and the optimal multiplexing method varies depending on the service requirements. However, in existing broadcast systems, it is necessary to select either FDM or TDM, and there is a problem that the optimal multiplexing method cannot be applied according to the service requirements.

[0010] Therefore, an object of the present invention is to provide a transmission device and a reception device that can apply an optimal multiplexing method according to service requirements in a broadcast system.

Means for Solving the Problems

[0011] The transmission device according to the first aspect is a transmission device used in a broadcast system that performs hierarchical transmission, and includes multiplexing means for multiplexing signals of a plurality of layers associated with different services respectively, and transmission means for transmitting the multiplexed signal by the multiplexing means. The multiplexing means has frequency division multiplexing means for multiplexing signals of two or more layers included in the plurality of layers by frequency division multiplexing within the transmission band of one channel, and time division multiplexing means for multiplexing signals of two or more layers included in the plurality of layers by time division multiplexing within one frame.

[0012] A receiving device according to a second aspect is a receiving device used in a broadcasting system that performs hierarchical transmission, and includes: receiving means for transmitting a multiplexed signal obtained by multiplexing signals of multiple layers, each corresponding to a different service, from a transmitting device; and demultiplexing means for demultiplexing the signals of the multiple layers from the multiplexed signal. The demultiplexing means includes frequency division demultiplexing means for demultiplexing signals of layers multiplexed by frequency division multiplexing within a transmission band of one channel, and time division demultiplexing means for demultiplexing signals of layers multiplexed by time division multiplexing within one frame. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a transmitting device and a receiving device in a broadcasting system that can apply an optimum multiplexing method according to the required conditions of the service. [Brief explanation of the drawings]

[0014]

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Embodiments for Carrying Out the Invention

[0015] 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.

[0016] (1) Broadcasting system First, with reference to FIGS. 1 to 3, the broadcasting system according to this embodiment will be described. The broadcasting system according to this embodiment is a system corresponding to the advanced terrestrial broadcasting system, and is a terrestrial digital television broadcasting system that performs hierarchical transmission.

[0017] (1.1) Transmission band in the broadcasting system With reference to FIG. 1, the transmission band in the broadcasting system according to this embodiment will be described. In this embodiment, it is assumed that the total bandwidth of one channel is 6 MHz.

[0018] 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 one segment is used as the partial reception band α for mobile reception services, and the remaining 12 segments are used 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 one segment, enabling a narrow-band receiving device to perform power-saving reception.

[0019] Here, the mobile reception layer is a layer to which transmission parameters (e.g., carrier modulation method, coding rate) having higher transmission tolerance than the fixed reception layer are applied. The fixed reception layer is a layer to which transmission parameters having 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 of supporting up to three-layer (A layer, B layer, C layer) hierarchical transmission and being able to set different transmission parameters for each layer will be described.

[0020] Figures 1(b) and (c) show the transmission bands of the advanced terrestrial broadcasting system. In the advanced terrestrial broadcasting system, it is being considered to divide the transmission band into a number of segments and more finely adjust the bit rate of each layer compared to ISDB-T. As shown in Figure 1(b), in the compatibility mode of the advanced terrestrial broadcasting system, the bandwidth of one channel is the same 5.57 MHz as that of ISDB-T. The number of segments in the transmission band is, for example, 33, and both end portions of the transmission band are adjustment bands. As shown in Figure 1(c), in the normal mode of the advanced terrestrial broadcasting system, the transmission bandwidth is expanded compared to ISDB-T, and is, for example, a transmission bandwidth of 5.83 MHz. The number of segments in the transmission band is, for example, 35. In both 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.

[0021] Thus, in the advanced terrestrial broadcasting system, a plurality of bandwidths are defined as the bandwidth corresponding to one channel. Also, in the advanced terrestrial broadcasting system, it is assumed to inherit the features of ISDB-T and perform hierarchical transmission based on FDM. However, FDM has disadvantages compared to TDM. Therefore, the broadcasting system according to the present embodiment is a broadcasting method that can support both multiplexing methods of TDM and FDM.

[0022] (1.2) Outline of the multiplexing method Referring to Figure 2, the characteristics of TDM and FDM will be described.

[0023] Regarding synchronous performance, TDM can perform signal detection in a short time and various synchronizations (frequency synchronization, symbol synchronization, frame synchronization) using a preamble signal at the head of a frame (the head of a signal). In contrast, 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 TDM is superior to FDM in terms of synchronous performance regarding initial signal detection. Thus, in this embodiment, a broadcasting method is adopted in which the merits of TDM are utilized by arranging a preamble signal at the head portion of a frame. Further, in this embodiment, a TMCC signal is arranged at a time position following the preamble signal, and a broadcasting method is adopted in which transmission parameters of subsequent subframes and layers are notified to a receiving device by the TMCC signal.

[0024] 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 for modulation / demodulation processing of an OFDM (Orthogonal Frequency Division Multiplexing) signal. For example, when the FFT size is 8192, it shall be expressed as 8kFFT. For example, mobile reception can use 8kFFT and fixed reception can use 32kFFT. In contrast, in FDM, it is necessary to use the same FFT size (for example, 16kFFT) for 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, a broadcasting method is adopted in which the merits of TDM are utilized by dividing a frame into a plurality of subframes and making it possible to set the FFT size individually for each subframe.

[0025] Regarding power saving, in TDM, power saving can be achieved by using a time-division receiver on the receiving device side and turning the RF circuit on and off. In contrast, in FDM, a frequency-division receiver is used on the receiving device side for narrowband reception. Power saving is possible due to the narrowing of 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, it becomes possible to use time-division reception and frequency-division reception in combination, and further power saving can be realized.

[0026] Regarding scalability, in TDM, it is easy to add subframes and introduce signals for new services. In contrast, in FDM, expansion is relatively difficult. Therefore, it can be said that TDM is superior to FDM in terms of scalability. Thus, in this embodiment, a subframe for transmitting signals of a new service is added to enable the introduction of an expansion frame, and a broadcasting method that makes use of the advantages of TDM is adopted.

[0027] Regarding multipath characteristics, in TDM, since the receiving device receives in a wideband, it is strong against frequency-selective fading (i.e., the effect of frequency interleaving is high). In contrast, in FDM, although wideband reception is possible in the fixed reception layer, narrowband reception is performed in the mobile reception layer, so the resistance becomes weak (i.e., the effect of frequency interleaving is low in narrowband reception). Therefore, it can be said that TDM is superior to FDM in terms of multipath characteristics.

[0028] Regarding speed tolerance, at low speeds, in TDM, the signals are intermittent in the time direction, making it difficult to obtain the effect of time interleaving. However, in FDM, the signals are continuous in the time direction, so the effect of time interleaving is high. Therefore, it can be said that FDM is superior to TDM in terms of speed tolerance at low speeds. 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 takes advantage of the merits of FDM is adopted. Regarding 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.

[0029] As described above, FDM and TDM each have different merits, and the optimal multiplexing method varies depending on the service requirements. In this embodiment, in the broadcasting system, a broadcasting method that can apply the optimal multiplexing method according to the service requirements is adopted. 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.

[0030] In addition, in this embodiment, a signal configuration is introduced that can multiplex a plurality of subframes continuously in the time direction like TDM, and within each subframe, multiplexing by hierarchical division can be performed in units of segments like FDM. Also, in this embodiment, both signal multiplexing like TDM using a plurality of subframes and signal multiplexing like FDM using a plurality of layers in one subframe are supported. Note that a configuration in which only a specific subframe is hierarchically divided by FDM is also possible.

[0031] (1.3) Schematic Configuration of Broadcasting System Referring to FIG. 3, the schematic configuration of the broadcasting system 1 according to this embodiment will be described. The broadcasting 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.

[0032] (1.3.1) Schematic Configuration of 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.

[0033] 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 a frame. The preamble signal is a signal used by the receiving device 200 to establish synchronization. The preamble signal is configured to include information necessary for the receiving 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 receiving device 200 to receive the hierarchical signal.

[0034] 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, on / off of partial reception becomes possible. 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.

[0035] 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 a 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 coding rate can be variably set under the condition that 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.

[0036] 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. Thereby, it becomes 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. In the receiving device 200 that does not correspond to the signal of the extended frame, it can receive a normal sub - frame while ignoring the extended frame.

[0037] 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.

[0038] The hierarchical signal generation means 102 generates signals of a plurality of hierarchies associated with different services respectively. For example, the services include a service for mobile reception and a service for fixed reception. 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.

[0039] 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 the broadcaster can apply an optimal multiplexing method according to the service requirement conditions.

[0040] 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 it into segments of two or more hierarchies in the frequency direction within each sub-frame, it becomes possible to combine TDM and FDM. As a result, efficient broadcast transmission becomes possible by taking advantage of the merits of TDM and FDM respectively.

[0041] 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 the synchronization and control of the broadcast transmission in the leading time interval in the frame, the receiving apparatus 200 can establish synchronization early at the frame head.

[0042] The FDM means 103a may arrange the segments of a specific layer (for example, layer A) associated with the mobile reception service in the partial reception band within the transmission band in a sub-frame including the segments of the specific layer. Thereby, even while using TDM, partial reception by FDM such as ISDB-T becomes possible. Further, the FDM means 103a may arrange the TMCC signal associated with the mobile reception service within the partial reception band. Thereby, partial reception of the TMCC signal becomes possible.

[0043] 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, the service expansion becomes easy.

[0044] 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 multiple antenna transmission using two or more transmission antennas. In the present embodiment, it is assumed that the transmission means 104 corresponds to multiple 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 symbol sets are used in the time direction, and complex conjugate and code inversion of the data carrier symbols are performed. In SFBC, two data symbol sets are used in the frequency direction, and complex conjugate and code inversion of the data carrier symbols are performed.

[0045] (1.3.2) Schematic Configuration of Receiver The receiver 200 includes a receiving means 201, a control signal processing means 202, a demultiplexing means 203, and a hierarchical signal processing means 204.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] The layer signal processing means 204 processes (demodulates and decodes) the layer signals output by the multi-separation means 203 based on the transmission parameters output by the TMCC signal processing unit 33 to obtain layer data (for example, video data), and outputs the obtained layer data.

[0050] (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.

[0051] (2.1) TDM arrangement, FDM arrangement With reference to FIG. 4, a signal configuration example when TDM arrangement and FDM arrangement are used in the signal configuration of the layer signal will be described. FIG. 4(a) shows a signal configuration example when TDM arrangement is used in the signal configuration of the layer signal, and FIG. 4(b) shows a signal configuration example when FDM arrangement is used in the signal configuration of the layer signal. Note that the bandwidth of the transmission band may be in the normal mode or the compatibility mode.

[0052] 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 leading part of the frame 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.

[0053] 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 specifiable in units of segments less than 1 (for example, 1 / 3 segment).

[0054] (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 in terms of the differences from Fig. 4.

[0055] 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.

[0056] 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 voice service of mobile reception is desired to have high resistance.

[0057] (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.

[0058] 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 and transmitted. That is, the transmitting device 100 aggregates the TMCC signals for partial reception to the bandwidth for performing narrow - band reception.

[0059] 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.

[0060] (2.4) Frame for expansion Referring to Fig. 7, a signal configuration example when a frame for expansion is introduced will be described. When introducing a frame for expansion, the transmitting device 100 notifies the receiving device 200 that the subframe is a frame for expansion based on the TMCC information for each subframe in the TMCC signal. The length of the frame for expansion is specified in units of the number of clocks. When the receiving device 200 that does not correspond to the frame for expansion receives a notification that it is a frame for expansion from TMCC, it ignores the signal during this period.

[0061] (2.5) Frame boundary pilot Referring to Fig. 8, a signal configuration example when a frame boundary pilot is used will be described.

[0062] The transmitting device 100 may arrange frame boundary SPs (Scattered Pilots) at the first symbol and the last symbol within 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. The 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.

[0063] 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".

[0064] (3) An example of a transmitting device With reference to FIG. 9, an example of the transmitting device 100 according to the present embodiment will be described.

[0065] 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.

[0066] 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 adopted. 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 adopted. 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 adopted.

[0067] The subframe A configuration unit 130a includes energy diffusion units 11 (11a, 11b, 11c) provided for each layer, error correction coding 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 coding units 12, and the carrier modulation units 13 constitute at least a part of the above-described layer signal generation means 102.

[0068] 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 the 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.

[0069] 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.

[0070] The hierarchical synthesis units 15 (151, 152) perform hierarchical synthesis processing on the hierarchical signals of the corresponding systems, and output the hierarchical signals after the hierarchical synthesis processing. The band division units 16 (161, 162) perform band division processing on the hierarchically synthesized signals to divide them into respective bands, and output the hierarchical signals 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 units 17 (171, 172) perform interleaving processing in the time direction (i.e., the symbol arrangement order direction in each carrier) on the band-divided hierarchical signals, and output the hierarchical signals after time interleaving. The frequency interleaving units 18 (181, 182) perform interleaving processing in the frequency direction on the hierarchical signals after time interleaving, and output the hierarchical signals after frequency interleaving. The band synthesis units 19 (191, 192) synthesize the signals of each band after frequency interleaving to form data segments. The frame configuration units 20 (201, 202) add a pilot signal (SP) and an Lch signal to the input carrier symbols (data segments) to form an OFDM frame. The IFFT units 21 (211, 212) perform IFFT processing on the OFDM frame to generate valid symbol signals. The GI addition units 22 (221, 222) add 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 units 20, the IFFT units 21, and the GI addition units 22 constitute an OFDM modulation unit. The MISO encoding unit 23 performs space-time encoding (STBC encoding or SFBC encoding) on the signals of one system to generate signals of two systems. The switching unit 24 selects the output from the two-system band synthesis unit 192 in the case of spatial 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 with the processing of the system separation unit 14.

[0071] 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 the multiplexed signal.

[0072] 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.

[0073] (4) Preamble signal With reference to FIGS. 10 to 16, the preamble signal according to this embodiment will be described.

[0074] (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 this embodiment will be described.

[0075] 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.

[0076] 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.

[0077] [Number] However, q is set to 137, and k = 0, 1, 2, …, N ZC is -1.

[0078] The mapping unit 112 maps the preamble signal sequence to a number of carriers corresponding to one of the multiple bandwidths used for broadcast transmission. 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 (first bandwidth) and the narrower compatibility mode bandwidth (second bandwidth) 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 have carriers (at the band edge) to "0" for the OFDM signal in the frequency domain in the compatibility mode.

[0079] 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.

[0080] The control information generation unit 114 generates the control information transmitted by the preamble signal. The control information transmitted by the preamble signal includes the transmission parameters related to the TMCC signal. The details of the information transmitted by the preamble signal will be described later.

[0081] 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.

[0082] The cyclic shift unit 117 performs time shift processing with 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 a 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 2048 with a maximum of 11 bits, 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 that does not carry control information, and control information is transmitted from the second symbol (preamble symbol #1) onward.

[0083] In this way, since the control information is carried on the shift amount (phase rotation amount) indicating 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.

[0084] 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.

[0085] 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 device 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 bandwidth is enabled. Thereby, the receiving device 200 can identify partial reception by demodulating the preamble signal.

[0086] (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.

[0087] (4.2.1) Operation example of preamble signal generation unit in compatibility mode FIG. 11(a) shows the operation when the preamble signal is made compatible with 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 in "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 the same detection method can be used for demodulation 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 converting to a time signal.

[0088] (4.2.2) Operation example of preamble signal generation unit in partial reception bandwidth 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 can be 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.

[0089] FIG. 11(b) shows the operation when generating a preamble signal for a 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 smaller than the normal value as N ZC 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 ZC which is the number of carriers, the preamble signal can be contained within the partial reception band.

[0090] 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.

[0091] (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.

[0092] 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.

[0093] 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 (sub-frame).

[0094] 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 the TMCC information once. Details of the TMCC page number will be described later.

[0095] 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 encoding (i.e., the encoding method applied to the SP of the TMCC signal)".

[0096] 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.

[0097] (5) TMCC signal The TMCC signal according to the present embodiment will be described with reference to FIGS. 17 to 26.

[0098] (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 the present embodiment will be described.

[0099] The TMCC signal generation unit 120 includes a TMCC information generation unit 120a, an energy diffusion unit 121, an error correction encoding unit 122, a turbo encoding 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.

[0100] The TMCC information generation unit 120a generates TMCC information with a variable number of bits according to the number of sub-frames in a frame and the number of layers in each sub-frame. As described above, there are significant differences in the TMCC information transmitted by the TMCC signal between the case of performing multi-sub-frame and multi-layer transmission and the case of performing single-sub-frame and single-layer transmission. By making the number of bits of the TMCC information variable according to the number of sub-frames in a frame and the number of layers in each sub-frame, the TMCC signal can be transmitted efficiently and in a highly scalable manner.

[0101] 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), a 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.

[0102] (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 this embodiment will be described.

[0103] The TMCC information generation unit 120a configures the 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.

[0104] 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 "frame", one "sub-frame", and one "layer" information block respectively 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 "frame" and one "sub-frame" information block each, 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.

[0105] With reference to FIG. 19, an operation example of the error correction encoding unit 122 according to this embodiment will be described.

[0106] Although the upper limit of the information bits storable in an FEC block is fixed, since the number of bits of TMCC information is variable, the number of bits of TMCC information stored in an FEC block may exceed the upper limit of the FEC block. When the number of bits of TMCC information exceeds the upper limit of the information bits storable in one FEC block, the error correction encoding unit 122 allocates the TMCC information across two or more FEC blocks. For example, when an LDPC code (1224, 256) is used as the error correction code and the number of bits of TMCC information is larger than 256 bits, which is the upper limit of the number of information bits of the FEC block, the error correction encoding unit 122 increases the number of pages (i.e., the number of FEC blocks), allocates the TMCC information to a plurality of FEC blocks, and pads the shortage with zeros. An example where the number of pages is 1 page is shown in FIG. 19(a), and an example where the number of pages is 2 pages is shown in FIG. 19(b). Thereby, even when the number of bits of TMCC information is large, the TMCC information can be transmitted appropriately.

[0107] Referring to FIG. 20, an operation example of the iterative encoding unit 123 according to the present embodiment will be described.

[0108] 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)) in order to improve the transmission tolerance. 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 repetitions is transmitted by a preamble signal. The repeated FEC blocks are transmitted with the number of symbols required for the repetition.

[0109] Referring to FIG. 21, the relationship between the number of repetitions and the number of symbols depending on the difference in the number of pages will be described.

[0110] When using (1224, 256) for the error correction code, for the TMCC information with the configuration shown in Fig. 21(a), as shown in Fig. 21(b), the number of bits of the TMCC information increases as the number of sub-frames increases. When the number of sub-frames becomes 3, 2 pages are required. As shown in Fig. 21(c), in both the case where the number of pages is "1" and the case where the number of pages is "2", the number of required symbols increases as the number of iterations increases.

[0111] Referring to Figs. 22 and 23, an example of information allocation of the TMCC signal in the case of partial reception will be described.

[0112] 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 achieve FEC block synchronization within the TMCC, when the TMCC signal generation unit 120 allocates FEC blocks, it starts the allocation from segments within the partial reception band. 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 within the partial reception band. Also, as shown in Fig. 23, the TMCC signal generation unit 120 can also preferentially allocate from the symbols of the partial reception band. Specifically, the TMCC signal generation unit 120 starts the allocation of the FEC block from one end segment within the partial reception band at symbol #0 within the time interval in which the TMCC signal is arranged. When reaching the middle of the FEC block at the other end within the partial reception band, it wraps around to symbol #1 within the time interval in which the TMCC signal is arranged and arranges the remaining part of the FEC block. Thereby, it becomes even easier for the receiving device 200 that performs narrowband reception to demodulate the TMCC signal.

[0113] (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.

[0114] 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 indicator", 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 indicator" 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.

[0115] 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 "GI ratio" can be selected from a plurality of candidates. Thereby, the "FFT size" and "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.

[0116] FIG. 26 shows the information included in the "hierarchy" information block of the TMCC information. As shown in FIG. 26, the 56-bit "hierarchy" information block includes information on the transmission parameters of the corresponding hierarchy. Specifically, the "hierarchy" information block consists of 7 bits of "number of segments", 3 bits of "carrier modulation", 1 bit of "UC / NUC", 2 bits of "code length", 4 bits of "coding rate", 4 bits of "SP arrangement", 1 bit of "SP coding", 1 bit of "frame boundary SP (beginning)", 1 bit of "frame boundary SP (end)", 1 bit of "all carrier pilots", 3 bits of "SP level", 3 bits of "time IL", 18 bits of "FEC pointer", 3 bits of "data carrier boost", and 4 bits of "reservation". Here, the "number of segments" is information indicating the number of segments constituting the hierarchy, and it can be specified in units of 1 / 3 segments. "Carrier modulation" indicates the carrier modulation method applied to the hierarchy. "UC / NUC" indicates whether the constellation (I-Q constellation) applied to the hierarchy is uniform (UC) or non-uniform (NUC). "Code length" indicates whether the error correction code length applied to the hierarchy is short, middle, or long. "Coding rate" indicates the coding rate of error correction applied to the hierarchy. "SP arrangement" indicates the arrangement pattern of the SP applied to the hierarchy. "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 hierarchy, and "frame boundary SP (end)" indicates whether the frame boundary SP (end) is applied to the hierarchy. "All carrier pilots" indicates whether all carrier pilots are applied to the hierarchy. "SP level" indicates the SP level applied to the hierarchy. "Time IL" indicates the time interleaving length applied to the hierarchy. "FEC pointer" indicates the FEC block pointer applied to the hierarchy. "Data carrier boost" indicates the power boost ratio applied to the hierarchy.

[0117] (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.

[0118] 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.

[0119] 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. 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 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.

[0120] The hierarchical signal processing means 204 includes a frequency deinterleave (DIL) section 39 (39a, 39b, 39c) provided for each hierarchy, a time DIL section 40 (40a, 40b, 40c) provided for each hierarchy, an LLR calculation section 41 (41a, 41b, 41c) provided for each hierarchy, an error correction decoding section 42 (42a, 42b, 42c) provided for each hierarchy, and an energy inverse spreading section 43 (43a, 43b, 43c) provided for each hierarchy. The frequency DIL section 39 (39a, 39b, 39c) performs deinterleaving in the carrier frequency direction for the carrier symbols of the corresponding hierarchy. The time DIL section 40 (40a, 40b, 40c) performs deinterleaving in the time direction for the frequency deinterleaved carrier symbols and returns them to the original array before interleaving 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 hierarchy. The error correction decoding section 42 (42a, 42b, 42c) performs error correction decoding processing based on the LLR. The energy inverse spreading section 43 (43a, 43b, 43c) performs energy inverse spreading processing on the hierarchical signal after the error correction decoding processing and outputs it.

[0121] (7) Other Embodiments The above-mentioned 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-mentioned 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.

[0122] A program may be provided that causes a computer to execute each process performed by each of the above-described apparatuses (transmission apparatus 100, reception apparatus 200). The program may be recorded on a computer-readable medium. By using a computer-readable medium, it is possible to install the program in 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 apparatuses (transmission apparatus 100, reception apparatus 200) may be integrated, and the apparatuses may be configured by a semiconductor integrated circuit (chip set, SoC).

[0123] 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 gist.

Explanation of Reference Numerals

[0124] 1: Broadcasting system 11: Energy dispersal unit 12: Error correction coding unit 13: Carrier modulation unit 14: System separation unit 15: Hierarchical synthesis unit 16: Band division unit 17: Time interleaving unit 18: Frequency interleaving unit 19: Band synthesis unit 20: Frame configuration unit 21: IFFT unit 22: GI addition unit 23: MISO coding unit 24: Switching unit 25: Quadrature modulation unit 26: DAC unit 27: IFFT unit 31: Reception unit 32: Preamble signal processing unit 33: TMCC signal processing unit 34: Target subframe 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 coding section 123: Iterative coding 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: Subframe A configuration section 130b: Subframe B configuration section 130c: Extended frame configuration 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 that performs hierarchical transmission, comprising: multiplexing means for multiplexing a plurality of layers of signals associated with different services respectively; transmission means for transmitting the multiplexed signal multiplexed by the multiplexing means, wherein the multiplexing means frequency-division multiplexing means for multiplexing signals of two or more layers included in the plurality of layers by frequency-division multiplexing within the transmission band of one channel; time-division multiplexing means for multiplexing signals of two or more layers included in the plurality of layers by time-division multiplexing within one frame, wherein the time-division multiplexing means performs the time-division multiplexing by dividing the frame into a plurality of sub-frames in the time direction, and the frequency-division multiplexing means performs the frequency-division multiplexing by dividing the transmission band of the channel into segments of two or more layers in the frequency direction in at least one of the plurality of sub-frames. A transmission device characterized by this.

2. further comprising control signal generation means for generating a control signal used for synchronization and control in broadcast transmission, wherein the time-division multiplexing means arranges the control signal in the leading time interval in the frame and arranges one or more sub-frames after the leading time interval. The transmission device according to Claim 1, characterized by this.

3. The transmission device according to Claim 2, characterized in that the control signal generation means generates the control signal including information indicating the number of sub-frames in the frame and information indicating the number of layers in each sub-frame.

4. The transmission device according to Claim 2 or 3, characterized in that the control signal generation means generates the 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.

5. The plurality of layers includes a specific layer associated with a mobile reception service, wherein the frequency-division multiplexing means arranges the segment of the specific layer within the partial reception band of the transmission band of the channel in a sub-frame including the segment of the specific layer. The transmission device according to any one of Claims 2 to 4, characterized by this.

6. The control signal includes a preamble signal arranged at the leading portion of the frame and a TMCC signal following the preamble signal. The transmission apparatus according to claim 5, wherein the frequency division multiplexing means arranges the TMCC signal associated with the mobile reception service within the partial reception band.

7. The transmission apparatus according to claim 5 or 6, wherein the control signal generation means generates the control signal including information indicating whether partial reception using the partial reception band is enabled.

8. The time division multiplexing means multiplexes, by time division multiplexing, at least one subframe in which the signals of the plurality of layers are arranged and a subframe used as an extension frame. The transmission apparatus according to any one of claims 2 to 7, wherein when the control signal generation means provides a subframe used as the extension frame, the control signal generation means generates the control signal including information indicating that the subframe is the extension frame.

9. The length of the extension frame is a length specified in units of the number of clocks. The transmission apparatus according to claim 8.

10. The transmission apparatus further includes control signal generation means for generating a control signal used for synchronization and control in broadcast transmission. The control signal includes a preamble signal arranged at the head portion of the frame and a TMCC signal arranged at a time position subsequent to the preamble signal. The transmission apparatus according to claim 1, wherein the TMCC signal includes information indicating the number of the layers by frequency division multiplexing within at least one subframe among a plurality of subframes constituting the one frame.

11. A receiving apparatus used in a broadcast system that performs hierarchical transmission, comprising: receiving means for receiving, from a transmission apparatus, a multiplexed signal obtained by multiplexing signals of a plurality of layers associated with different services respectively; demultiplexing means for demultiplexing the signals of the plurality of layers from the multiplexed signal. The demultiplexing means includes: frequency division multiplexing demultiplexing means for demultiplexing signals of layers multiplexed by frequency division multiplexing within a transmission band of one channel; time division multiplexing demultiplexing means for demultiplexing signals of layers multiplexed by time division multiplexing within one frame including a plurality of subframes. The time division multiplexing demultiplexing means separates at least one subframe multiplexed by frequency division multiplexing from the signals of the layers multiplexed by time division multiplexing within the one frame. The frequency division multiplexing separation means separates and outputs a hierarchical signal associated with a predetermined service from at least one subframe separated by the time division multiplexing separation means and multiplexed by the frequency division multiplexing. A receiving apparatus characterized by this.

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