JP2015211435A - Transmitter, receiver, chip, and digital broadcasting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter, receiver, chip, and digital broadcasting system capable of receiving hierarchical data corresponding to part of of a hierarchy while reducing processing load and power consumption of a receiver.SOLUTION: A transmitter 100 includes a MIMO-OFDM modulation section 120 which adds a guard interval to a transmission frame on the basis of FFT size of a data symbol and a guard interval ratio. The transmission frame includes a preamble including a control signal indicating the FFT size of the data symbol and the guard interval ratio. The preamble is included individually for each segment corresponding to each of a plurality of hierarchy levels.

Description

  The present invention relates to a transmission device, a reception device, a chip, and a digital broadcasting system.

  In the ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) system, which is a digital terrestrial broadcasting system in Japan, a plurality of layered data (for example, one segment, 13 segments) corresponding to each of a plurality of layers is transmitted. The plurality of hierarchized data is transmitted using a plurality of segments (frequency bands) provided along the frequency direction. A transmission control signal (TMCC signal) indicating transmission parameters (modulation method, number of segments, coding rate, etc.) of each layer is inserted into each segment.

  By the way, the transmission apparatus transmits a transmission frame (OFDM frame) constituted by the data symbols and the transmission parameters to the reception apparatus. The transmission frame includes a guard interval (GI) that is a copy of a part of a data symbol at a constant period, and the receiving apparatus performs synchronization detection based on a correlation peak of the guard interval (for example, Non-Patent Document 1). 2).

"Study of new frequency synchronization method using guard correlation in OFDM", Seki, Television Society Technical Report, Vol. 19, N 0.38, p. 13 "Transmission standard for digital terrestrial television broadcasting" ARIB STD-B31

  By the way, in the above-described technique, the synchronization detection is performed by the correlation peak of the guard interval. However, in order to perform the synchronization detection, it is necessary for the receiving apparatus to know the FFT size and the guard interval ratio of the data symbol.

  In the above-described technique, the FFT size is 3 patterns and the guard interval ratio is 4 patterns, so the combination of the FFT size and the guard interval ratio is 12 patterns. Therefore, the receiving apparatus specifies the combination in which the correlation peak of the guard interval is detected as a combination of the FFT size and the guard interval ratio by applying all patterns to the transmission frame.

  However, in the next-generation terrestrial broadcasting system, the number of combinations of FFT sizes and guard interval ratios can be increased. Therefore, when all patterns of combinations of FFT sizes and guard interval ratios are applied to transmission frames, Processing load and power consumption increase. In addition, the time from selection of a channel to normal output of video and audio, so-called zapping time, becomes long.

  Therefore, the present invention has been made to solve the above-described problems, and can receive hierarchical data corresponding to a part of the hierarchy while reducing the processing load and power consumption of the receiving apparatus. It is an object of the present invention to provide a transmitter, a receiver, a chip, and a digital broadcasting system.

  A first feature is that in a digital broadcasting system in which a plurality of layered data corresponding to each of a plurality of layers is transmitted using a plurality of segments provided along the frequency direction, the plurality of layered data is A transmission apparatus for transmitting, wherein data frames corresponding to each of the plurality of hierarchized data are generated, and a transmission frame configured by data symbols assigned to each segment corresponding to each of the plurality of hierarchies is generated A transmission frame generation unit that adds a guard interval to the transmission frame based on an FFT size and a guard interval ratio of the data symbol, and the transmission frame includes an FFT size and a guard of the data symbol Including a preamble including a control signal indicating an interval ratio, Preamble is summarized in that included in the individual for each segment corresponding to each of the plurality of hierarchies.

  The second feature is that in a digital broadcasting system in which a plurality of hierarchized data corresponding to each of a plurality of hierarchies is transmitted using a plurality of segments provided along the frequency direction, at least one of the plurality of hierarchies is transmitted. A receiving apparatus for receiving a radio signal corresponding to one hierarchy, comprising a demodulator that demodulates the radio signal corresponding to the at least one hierarchy, and a data symbol corresponding to each of the plurality of hierarchical data In addition, a transmission frame configured by data symbols assigned to each segment corresponding to each of the plurality of layers has a guard interval added based on the FFT size and guard interval ratio of the data symbols, The transmission frame has the FFT size and guard interval ratio of the data symbol. A preamble including a control signal, wherein the preamble is individually included for each segment corresponding to each of the plurality of hierarchies, and the demodulator is included in the segment corresponding to the at least one hierarchy The gist is to detect a preamble and specify an FFT size and a guard interval ratio of the data symbol based on the control signal included in the detected preamble.

  A third feature is that in a digital broadcasting system in which a plurality of layered data corresponding to each of a plurality of layers is transmitted using a plurality of segments provided along the frequency direction, at least one of the plurality of layers is transmitted. A chip mounted on a receiving device that receives radio signals corresponding to one layer, and includes a demodulator that demodulates the radio signal corresponding to the at least one layer, and corresponds to each of the plurality of layered data A guard frame is added to a transmission frame composed of data symbols assigned to each segment corresponding to each of the plurality of hierarchies based on the FFT size and guard interval ratio of the data symbols. The transmission frame includes an FFT size and a guard of the data symbol. A preamble including a control signal indicating an interval ratio, wherein the preamble is individually included for each segment corresponding to each of the plurality of hierarchies, and the demodulator includes a segment corresponding to the at least one hierarchy The gist of the invention is to detect the included preamble and to specify an FFT size and a guard interval ratio of the data symbol based on the control signal included in the detected preamble.

  A fourth feature is a digital broadcasting system in which a plurality of hierarchized data corresponding to each of a plurality of hierarchies is transmitted from a transmitting device to a receiving device using a plurality of segments provided along the frequency direction. The transmission apparatus generates a transmission frame configured by data symbols corresponding to each of the plurality of hierarchized data and allocated to each segment corresponding to each of the plurality of hierarchies. A frame generation unit; and a GI addition unit that adds a guard interval to the transmission frame based on an FFT size and a guard interval ratio of the data symbol, and the reception apparatus receives a radio signal corresponding to at least one layer. A demodulator for demodulating, wherein the transmission frame includes an FFT size and a data symbol. A preamble including a control signal indicating a guard interval ratio, wherein the preamble is individually included for each segment corresponding to each of the plurality of hierarchies, and the demodulator includes a segment corresponding to the at least one hierarchy The preamble included in the data symbol is detected, and the FFT size and guard interval ratio of the data symbol are specified based on the control signal included in the detected preamble.

  According to the present invention, a transmitter, a receiver, a chip, and a digital broadcasting system that can receive hierarchical data corresponding to a part of layers while reducing the processing load and power consumption of the receiver. Can be provided.

FIG. 1 is a block diagram illustrating a transmission device 100 according to the first embodiment. FIG. 2 is a block diagram illustrating the receiving device 200 according to the first embodiment. FIG. 3 is a diagram for explaining a first example of a preamble according to the first embodiment. FIG. 4 is a diagram for explaining a second example of the preamble according to the first embodiment. FIG. 5 is a diagram for explaining a second example of the preamble according to the first embodiment. FIG. 6 is a diagram for explaining a third example of the preamble according to the first embodiment. FIG. 7 is a diagram for explaining a third example of the preamble according to the first embodiment. FIG. 8 is a diagram for explaining a third example of the preamble according to the first embodiment. FIG. 9 is a diagram for explaining a third example of the preamble according to the first embodiment. FIG. 10 is a diagram for explaining a reference example of the preamble according to the first embodiment.

  Next, an embodiment of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[Outline of Embodiment]
The transmitting apparatus according to the embodiment uses the plurality of hierarchized data in a digital broadcasting system in which a plurality of hierarchized data corresponding to each of a plurality of hierarchies is transmitted using a plurality of segments provided along the frequency direction. Send. A transmission apparatus generates a transmission frame that generates a transmission frame composed of data symbols corresponding to each of the plurality of layered data and assigned to each segment corresponding to each of the plurality of layers And a GI adding unit that adds a guard interval to the transmission frame based on the FFT size and guard interval ratio of the data symbol. The transmission frame includes a preamble including a control signal indicating an FFT size and a guard interval ratio of the data symbol. The preamble is individually included for each segment corresponding to each of the plurality of hierarchies.

  In the embodiment, a preamble including a control signal indicating the FFT size of a data symbol and a guard interval ratio is individually included for each segment corresponding to each of a plurality of layers. Therefore, even when the receiving apparatus receives hierarchical data corresponding to a part of the hierarchy, the receiving apparatus uses the preambles individually included in the segments corresponding to the part of the hierarchy, and the FFT size of the data symbol and The guard interval ratio can be specified. That is, since it is not necessary to apply the entire pattern of the combination of the FFT size and the guard interval ratio to the transmission frame, the processing load and power consumption of the receiving apparatus can be reduced, and the hierarchization corresponding to some hierarchies is possible. Data can also be received.

[First Embodiment]
(Digital broadcasting system)
Hereinafter, the digital broadcast system according to the first embodiment will be described. FIG. 1 is a block diagram illustrating a transmission device 100 according to the first embodiment, and FIG. 2 is a block diagram illustrating a reception device 200 according to the first embodiment. The digital broadcasting system includes a transmission device 100 and a reception device 200.

  In the embodiment, the digital broadcasting system is a digital broadcasting system compatible with the next generation terrestrial broadcasting system. For example, in a digital broadcasting system, MIMO (Multiple Input Multiple Output) technology and OFDM (Orthogonal Frequency Division Multiplexing) technology are applied. In the digital broadcasting system, a plurality of hierarchized data (for example, one segment and 13 segments) corresponding to each of a plurality of hierarchies are transmitted from the transmitting device 100 to the receiving device 200. The plurality of hierarchized data is transmitted using a plurality of segments (frequency bands) provided along the frequency direction.

  In the first embodiment, a case where A layer data, B layer data, and C layer data are transmitted as layered data will be exemplified. A layer data is transmitted using a segment corresponding to the A layer, B layer data is transmitted using a segment corresponding to the B layer, and C layer data is transmitted using a segment corresponding to the A layer. The

  As illustrated in FIG. 1, the transmission device 100 includes a plurality of hierarchical frame configuration units 110 and a MIMO-OFDM modulation unit 120 corresponding to each of a plurality of layers.

  Each of the plurality of hierarchical frame configuration units 110 configures a frame corresponding to each of the plurality of hierarchical data. As will be described later, the frame corresponding to the hierarchical data includes an error correction code block and a preamble. Specifically, the hierarchical frame configuration unit 110 includes an error correction encoding unit 111, a preamble generation unit 112, and a framing unit 113.

  In the first embodiment, as the hierarchical frame configuration unit 110, a hierarchical frame configuration unit 110A that configures a frame corresponding to layer A data, a hierarchical frame configuration unit 110B that configures a frame corresponding to layer B data, and C layer data A hierarchical frame configuration unit 110C that configures a frame corresponding to is provided.

  Note that the configuration of the hierarchical frame configuration unit 110B and the hierarchical frame configuration unit 110C is the same as that of the hierarchical frame configuration unit 110A. Therefore, in the following description, the description of the hierarchical frame configuration unit 110B and the hierarchical frame configuration unit 110C is omitted, and the hierarchical frame configuration unit 110A is described.

  The error correction encoding unit 111A generates an error correction code block having a fixed length. Specifically, the error correction encoding unit 111A adds an error correction code to input data such as a TS (Transport Stream) having a predetermined format for the A layer. Here, the error correction code block is an example of a unit bit string composed of a predetermined number of bits. The error correction code block includes a header, a payload, and parity bits, and has a bit length of 64800, for example.

  The preamble generation unit 112A generates a preamble including a control signal indicating the FFT size of the data symbol and the guard interval ratio for the A layer. It should be noted that the preambles generated by the preamble generator 112A are individually included in segments corresponding to the A layer. Details of the preamble will be described later (see FIGS. 3 to 9).

  Here, the preamble is arranged across a plurality of carriers, and is multiplexed into an OFDM frame by TDM. The preamble only needs to include a control signal indicating at least the FFT size and guard interval ratio of the data symbol. In addition to such a control signal, the preamble may include information indicating a multiplexing method of multiple streams (FDM, TDM or both FDM and TDM), a transmission signal format (MIMO, MISO, or SISO), and the like. Good.

  Further, the preamble may include a known pilot signal for calculating a propagation path response in receiving apparatus 200. The pilot signal is preferably embedded in all carriers, but may be embedded in some carriers. Further, the pilot signal is preferably embedded in at least one carrier in all segments. As a result, the preamble can also be used as a reference signal, and the transmission path response can be accurately calculated in the receiving apparatus 200.

  The framing unit 113A generates a frame composed of an error correction code block and a preamble for the A layer.

  The MIMO-OFDM modulation unit 120 generates a transmission frame (hereinafter referred to as an OFDM frame) composed of the frames output from each hierarchical frame configuration unit 110. An OFDM frame is defined by a predetermined number of subcarriers (frequency axis) and a predetermined number of symbols (time axis).

  First, the MIMO-OFDM modulation unit 120 generates a data symbol sequence by mapping a data bit sequence included in a frame output from each hierarchical frame configuration unit 110 on the IQ plane. Second, MIMO-OFDM modulation section 120 performs spatial coding processing on each symbol included in the data symbol sequence to generate two systems of signals. The two signals may be the same signal, but are preferably different signals from the viewpoint of transmission efficiency. Thirdly, the MIMO-OFDM modulation section 120 performs carrier modulation, IFFT processing, and addition of guard intervals on the two systems of signals to generate radio signals Tx1 and Tx2. Here, it should be noted that a symbol corresponding to each layer is transmitted using a segment assigned to each layer.

  Although omitted in FIG. 1, it should be noted that the MIMO-OFDM modulation section 120 performs quadrature modulation and D / A conversion after adding a guard interval. In addition, it should be noted that the MIMO-OFDM modulation unit 120 transmits the radio signals Tx1 and Tx2 (radio signals corresponding to the OFDM frame) to the reception apparatus 200 using a plurality of antennas.

  It should be noted that the guard interval is added based on the FFT size of the data symbol and the guard interval ratio. The guard interval is a part of the time axis waveform of the data symbol (effective symbol) (the length of the predetermined ratio from the back), and is added to the head of the time waveform of the data symbol (effective symbol). As the FFT size of the data symbol, for example, three patterns of FFT sizes can be used. As the guard interval ratio, for example, four patterns of guard interval ratios can be used.

  That is, in the first embodiment, the MIMO-OFDM modulation unit 120 is configured with data symbols corresponding to each of a plurality of layered data and allocated to each segment corresponding to each of the plurality of layers. A transmission frame generation unit configured to generate a transmission frame to be transmitted. Further, MIMO-OFDM modulation section 120 constitutes a GI adding section that adds a guard interval to a transmission frame based on the FFT size of the data symbol and the guard interval ratio.

  Although not specifically mentioned in the above description, it should be noted that the MIMO-OFDM modulation unit 120 inserts a Transmission and Multiplexing Configuration Control (TMCC) signal into a transmission frame. The TMCC signal includes a signal indicating transmission parameters (modulation method, number of segments, coding rate, etc.) of each of a plurality of layers, and a synchronization signal for synchronizing an OFDM frame (transmission frame).

  As illustrated in FIG. 2, the reception device 200 includes a plurality of layer demodulation units 210 corresponding to the plurality of layers.

  Each of the plurality of hierarchy demodulation units 210 demodulates the radio signals Rx1 and Rx2 corresponding to each of the plurality of hierarchies. Specifically, the hierarchical demodulation unit 210 includes a preamble detection unit 211, a GI removal unit 212, a MIMO-OFDM demodulation unit 213, and an error correction code decoding unit 214. The receiving apparatus 200 is provided in, for example, a receiver fixedly installed in a home or a mobile terminal that can be carried by a user.

  Although omitted in FIG. 2, each of the plurality of hierarchical demodulation units 210 uses radio signals Rx1 and Rx2 (radio signals corresponding to OFDM frames) corresponding to each of the plurality of hierarchies using a plurality of antennas. It should be noted that the data is received from the transmission device 100. It should be noted that each of the plurality of hierarchical demodulation units 210 performs A / D conversion and orthogonal demodulation on the radio signals Rx1 and Rx2, and outputs two systems of signals.

  In the first embodiment, as the hierarchical demodulator 210, a hierarchical demodulator 210A that demodulates radio signals Rx1 and Rx2 corresponding to A layer data, a hierarchical demodulator 210B that demodulates radio signals Rx1 and Rx2 corresponding to B layer data, A hierarchical demodulator 210C that demodulates the radio signals Rx1 and Rx2 corresponding to the C hierarchical data is provided.

  Note that the configurations of the hierarchical demodulation unit 210B and the hierarchical demodulation unit 210C are the same as those of the hierarchical demodulation unit 210A. Therefore, in the following description, the hierarchical demodulator 210A will be described with the description of the hierarchical demodulator 210B and the hierarchical demodulator 210C omitted.

  The preamble detector 211A detects a preamble from each of the two systems of signals corresponding to the A layer data. As described above, the preamble includes the control signal indicating the FFT size of the data symbol and the guard interval ratio, and is individually included in the segment corresponding to the A layer. Preamble detecting section 211A specifies the FFT size and guard interval ratio of the data symbol based on the control signal included in the detected preamble. Details of the preamble will be described later (see FIGS. 3 to 9).

  The GI removal unit 212A removes the guard interval from each of the two systems of signals corresponding to the A layer data based on the FFT size and the guard interval ratio of the data symbol specified by the preamble detection unit 211A for the A layer.

  The MIMO-OFDM demodulation unit 213A acquires a transmission frame (OFDM frame) corresponding to the layer A from the signal output from the layer demodulation unit 210A. An OFDM frame is defined by a predetermined number of subcarriers (frequency axis) and a predetermined number of symbols (time axis).

  First, the MIMO-OFDM demodulation section 213A performs FFT processing, MIMO demodulation processing, and spatial code decoding processing on the two systems of signals from which the guard interval has been removed, and two systems of symbol sequences corresponding to the A layer To get. Second, MIMO-OFDM demodulation section 213A performs carrier demodulation on the two symbol sequences and outputs a bit string corresponding to the A layer.

  The error correction code decoding unit 214A extracts the error correction code block of the A layer data from the bit string corresponding to the A layer, and performs error correction of the bit string constituting the extracted error correction code block.

  Although FIG. 2 illustrates the case where the receiving apparatus 200 includes the hierarchical demodulation unit 210 that demodulates radio signals corresponding to all the hierarchical levels, the embodiment is not limited to this. The receiving apparatus 200 only needs to include the layer demodulation unit 210 that demodulates the radio signals Rx1 and Rx2 corresponding to at least one layer.

(First example of preamble)
Hereinafter, a first example of the preamble according to the first embodiment will be described with reference to FIG. In the following, a case where hierarchical data of two layers of layer A and layer B is transmitted will be exemplified. A preamble corresponding to layer A is transmitted using a segment corresponding to layer A, and a preamble corresponding to layer B is transmitted using a segment corresponding to layer B. The preamble is included at the beginning of the OFDM frame. It should be noted that these assumptions are the same in the second to third examples of the preamble.

  As shown in FIG. 3, in the first example of the preamble, the FFT size of the preamble is a fixed length. Further, the preamble may be configured only by the control signal. The preamble FFT size is preferably smaller than the data symbol FFT size, for example, 1 kFFT. Since the FFT size of the preamble is a fixed length, the preamble detector 211A can detect the preamble.

  As shown in FIG. 3, it is preferable that the preamble corresponding to layer B is not transmitted in the segments at both ends in the frequency direction among the plurality of segments corresponding to layer B. As a result, the disturbing radio wave deviated from the spectrum mask is suppressed. Further, it is preferable that the amplitude of the preamble carrier symbol is increased at a constant ratio so that the energy difference between the preamble and the data symbol does not occur due to this suppression.

  Further, when a plurality of segments are provided as segments corresponding to each layer, a preamble may be included for each of the plurality of segments. As a result, a diversity effect of the preamble can be obtained.

(Second example of preamble)
Below, the 2nd example of the preamble which concerns on 1st Embodiment is demonstrated, referring FIG.4 and FIG.5.

  As shown in FIG. 4, in the second example of the preamble, the FFT size of the control signal included in the preamble is a fixed length. The FFT size of the control signal included in the preamble is preferably smaller than the FFT size of the data symbol, for example, 1 kFFT. Since the FFT size of the control signal included in the preamble is a fixed length, the preamble detector 211A can detect the preamble.

  In addition, as shown in FIG. 4, it is preferable that the preamble corresponding to the hierarchy B is not transmitted by the segment of the both ends of a frequency direction among the some segments corresponding to the hierarchy B. As a result, the disturbing radio wave deviated from the spectrum mask is suppressed. Further, it is preferable that the amplitude of the preamble carrier symbol is increased at a constant ratio so that the energy difference between the preamble and the data symbol does not occur due to this suppression.

  Further, when a plurality of segments are provided as segments corresponding to each layer, a preamble may be included for each of the plurality of segments. As a result, a diversity effect of the preamble can be obtained.

  As shown in FIG. 5, the preamble is composed of a control signal and a dummy signal. Further, the symbol length of the preamble is the same as the symbol length of a unit configured by data symbols and guard intervals. Note that the dummy signal may be any signal. As a result, since the period in which the guard correlation is obtained is constant for the unit constituted by the data symbols excluding the preamble and the guard interval, the synchronization obtained by the guard correlation is more stable than in the first example of the preamble.

  In the second example of the preamble, the dummy signal constituting the preamble may include a known pilot signal for calculating a propagation path response in the receiving apparatus 200. The pilot signal is preferably embedded in all carriers, but may be embedded in some carriers. Further, the pilot signal is preferably embedded in at least one carrier in all segments. As a result, the preamble can also be used as a reference signal, and the transmission path response can be accurately calculated in the receiving apparatus 200.

(Third example of preamble)
Hereinafter, a third example of the preamble according to the first embodiment will be described with reference to FIGS.

  As shown in FIG. 6, in the third example of the preamble, the FFT size of the control signal included in the preamble is a fixed length. The FFT size of the control signal included in the preamble is preferably smaller than the FFT size of the data symbol, for example, 1 kFFT. Since the FFT size of the control signal included in the preamble is a fixed length, the preamble detector 211A can detect the preamble.

  As illustrated in FIG. 6, it is preferable that the preamble corresponding to layer B is not transmitted in the segments at both ends in the frequency direction among the plurality of segments corresponding to layer B. As a result, the disturbing radio wave deviated from the spectrum mask is suppressed. Further, it is preferable that the amplitude of the preamble carrier symbol is increased at a constant ratio so that the energy difference between the preamble and the data symbol does not occur due to this suppression.

  Further, when a plurality of segments are provided as segments corresponding to each layer, a preamble may be included for each of the plurality of segments. As a result, a diversity effect of the preamble can be obtained.

  Here, as shown in FIG. 7, the control signal included in the preamble includes a pair of detection portions and a main body portion sandwiched between the pair of detection portions in the symbol direction. The front detection part in the symbol direction is a first half copy of the main body part, and the rear detection part in the symbol direction is a second half copy of the main body part. Accordingly, the preamble detector 211A can detect the guard correlation of the control signal, and can identify the control signal by detecting the guard correlation of the control signal.

  Under such a premise, in option 1 of the third example of the preamble, as shown in FIG. 8, the preamble is composed of a control signal, a dummy signal, and a pseudo guard interval. The symbol length of the preamble is the same as the symbol length of a unit configured by data symbols and guard intervals. The symbol length of the pseudo guard interval is the same as the symbol length of the guard interval and is an integral multiple of the symbol length of the control signal. The pseudo guard interval is a copy of the control signal with an integer multiple of accuracy. Note that the dummy signal may be any signal.

  Alternatively, in option 2 of the third example of the preamble, the preamble is configured by a control signal, a dummy signal, and a pseudo guard interval as shown in FIG. The symbol length of the preamble is the same as the symbol length of a unit configured by data symbols and guard intervals. The symbol length of the pseudo guard interval is the same as the symbol length of the guard interval, and is an integral multiple of 1/2 of the symbol length of the control signal. In addition, the pseudo guard interval is a copy of the control signal with a precision of 1/2. Note that the dummy signal may be any signal.

  As described above, in options 1 and 2 of the third example of the preamble, the symbol length of the preamble is the same as the symbol length of the unit configured by the data symbol and the guard interval. As a result, since the period in which the guard correlation is obtained is constant for the unit constituted by the data symbol and the guard interval, the synchronization obtained by the guard correlation is more stable than in the first example of the preamble. Furthermore, since a pseudo guard interval having the same symbol length as the symbol length of the guard interval is provided, the period for obtaining the guard correlation is not interrupted even for the preamble, and the synchronization obtained by the guard correlation is further stabilized.

  Further, in option 2 of the third example of the preamble, since the symbol length of the pseudo guard interval is an integral multiple of 1/2 of the symbol length of the control signal, the data symbol of the data symbol is compared with option 1 of the third example of the preamble. It is possible to flexibly determine the values that the guard interval ratio can take.

  As described above, options 1 and 2 in the third example of the preamble are excellent, and option 2 in the third example of the preamble is particularly excellent.

  In the third example of the preamble, the dummy signal constituting the preamble may include a known pilot signal for calculating a propagation path response in the receiving apparatus 200. The pilot signal is preferably embedded in all carriers, but may be embedded in some carriers. Further, the pilot signal is preferably embedded in at least one carrier in all segments. As a result, the preamble can also be used as a reference signal, and the transmission path response can be accurately calculated in the receiving apparatus 200.

(Preamble reference example)
Hereinafter, a reference example of the preamble according to the first embodiment will be described with reference to FIG.

  As shown in FIG. 10, in the preamble reference example, the FFT size of the preamble is the same as the FFT size of the unit configured by the data symbol and the guard interval. Thereby, the data amount of the control signal included in the preamble can be increased as compared with the first example of the preamble. From the viewpoint of increasing the data amount of the control signal, the preamble is preferably composed only of the control signal.

  Further, the symbol length of the preamble is the same as the symbol length of a unit configured by data symbols and guard intervals. As a result, for the unit constituted by the data symbol and the guard interval, since the period in which the guard correlation is obtained is constant, the synchronization obtained by the guard correlation is stabilized compared to the first example of the preamble.

  In the preamble reference example, the preamble detection unit 211A needs to specify the FFT size of the preamble by applying a plurality of types of FFT sizes to the signal after A / D conversion and orthogonal demodulation. It should be noted.

(Function and effect)
In the first embodiment, a preamble including a control signal indicating the FFT size of a data symbol and a guard interval ratio is individually included for each segment corresponding to each of a plurality of hierarchies. Therefore, even when the receiving apparatus 200 receives layered data corresponding to some layers, the receiving apparatus 200 uses the preambles individually included in the segments corresponding to some layers to perform FFT of data symbols. The size and guard interval ratio can be specified. That is, since it is not necessary to apply the entire pattern of the combination of the FFT size and the guard interval ratio to the transmission frame, the processing load and power consumption of the receiving apparatus 200 can be reduced, and a hierarchy corresponding to a part of the hierarchy It is also possible to receive digitized data.

[Other Embodiments]
Although the present invention has been described with reference to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the embodiment, a system using a MIMO (Multiple Input Multiple Output) technology has been illustrated. However, the embodiment is not limited to this. The embodiment may be applied to a system in which a MISO (Multiple Input Single Output) technology or a SISO (Single Input Single Output) technology is used.

  In the embodiment, the preamble corresponding to each layer is generated by the layer frame configuration unit 110 that processes each layered data. However, the embodiment is not limited to this. For example, the MIMO-OFDM modulation unit 120 may generate a preamble corresponding to each layer.

  Although not specifically mentioned in the embodiment, a program for causing a computer to execute each process performed by the transmission device 100 and the reception device 200 may be provided. The program may be recorded on a computer readable medium. If a computer-readable medium is used, a program can be installed in the 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, but may be a recording medium such as a CD-ROM or a DVD-ROM.

  Alternatively, a chip configured by a memory that stores a program for executing each process performed by the transmission device 100 and the reception device 200 and a processor that executes the program stored in the memory may be provided.

  DESCRIPTION OF SYMBOLS 100 ... Transmission apparatus, 110 ... Hierarchical frame structure part, 111 ... Error correction encoding part, 112 ... Preamble generation part, 113 ... Frame formation part, 120 ... MIMO-OFDM modulation part, 200 ... Reception apparatus, 210 ... Hierarchy demodulation part , 211... Preamble detection unit, 212... GI removal unit, 213... MIMO-OFDM demodulation unit, 214.

Claims (10)

In a digital broadcasting system in which a plurality of hierarchized data corresponding to each of a plurality of hierarchies is transmitted using a plurality of segments provided along a frequency direction, the transmitting apparatus transmits the plurality of hierarchized data. And
A transmission frame generation unit that generates a transmission frame composed of data symbols corresponding to each of the plurality of hierarchized data and allocated to each segment corresponding to each of the plurality of hierarchies;
A GI adding unit that adds a guard interval to the transmission frame based on an FFT size of the data symbol and a guard interval ratio;
The transmission frame includes a preamble including a control signal indicating an FFT size and a guard interval ratio of the data symbol,
The transmission apparatus according to claim 1, wherein the preamble is individually included for each segment corresponding to each of the plurality of hierarchies.   The transmission apparatus according to claim 1, wherein an FFT size of the preamble is a fixed length. The FFT size of the control signal is a fixed length,
The preamble is composed of the control signal and a dummy signal,
The transmission apparatus according to claim 1, wherein a symbol length of the preamble is the same as a symbol length of a unit configured by the data symbol and the guard interval. The FFT size of the control signal is a fixed length,
The preamble is composed of the control signal, a dummy signal, and a pseudo guard interval.
The symbol length of the preamble is the same as the symbol length of the unit configured by the data symbol and the guard interval,
The transmission apparatus according to claim 1, wherein the symbol length of the pseudo guard interval is the same as the symbol length of the guard interval and is an integral multiple of the symbol length of the control signal. The FFT size of the control signal is a fixed length,
The preamble is composed of the control signal, a dummy signal, and a pseudo guard interval.
The symbol length of the preamble is the same as the symbol length of the unit configured by the data symbol and the guard interval,
2. The transmission device according to claim 1, wherein the symbol length of the pseudo guard interval is the same as the symbol length of the guard interval and is an integral multiple of ½ of the symbol length of the control signal. .   The transmitting apparatus according to claim 1, wherein the amplitude of the carrier symbol of the preamble is increased at a constant ratio.   The transmission apparatus according to claim 1, wherein the preamble includes a known pilot signal for calculating a propagation path response in the reception apparatus. In a digital broadcasting system in which a plurality of hierarchized data corresponding to each of a plurality of hierarchies is transmitted using a plurality of segments provided along the frequency direction, radio corresponding to at least one of the plurality of hierarchies A receiving device for receiving a signal,
A demodulator that demodulates a radio signal corresponding to the at least one layer;
A transmission frame composed of data symbols corresponding to each of the plurality of hierarchized data and assigned to each segment corresponding to each of the plurality of hierarchies includes an FFT size of the data symbol and A guard interval is added based on the guard interval ratio,
The transmission frame includes a preamble including a control signal indicating an FFT size and a guard interval ratio of the data symbol,
The preamble is individually included for each segment corresponding to each of the plurality of hierarchies,
The demodulator detects the preamble included in a segment corresponding to the at least one layer, and identifies an FFT size and a guard interval ratio of the data symbol based on the control signal included in the detected preamble A receiving apparatus. In a digital broadcasting system in which a plurality of hierarchized data corresponding to each of a plurality of hierarchies is transmitted using a plurality of segments provided along the frequency direction, radio corresponding to at least one of the plurality of hierarchies A chip mounted on a receiving device for receiving a signal,
A demodulator that demodulates a radio signal corresponding to the at least one layer;
A transmission frame composed of data symbols corresponding to each of the plurality of hierarchized data and assigned to each segment corresponding to each of the plurality of hierarchies includes an FFT size of the data symbol and A guard interval is added based on the guard interval ratio,
The transmission frame includes a preamble including a control signal indicating an FFT size and a guard interval ratio of the data symbol,
The preamble is individually included for each segment corresponding to each of the plurality of hierarchies,
The demodulator detects the preamble included in a segment corresponding to the at least one layer, and identifies an FFT size and a guard interval ratio of the data symbol based on the control signal included in the detected preamble A chip characterized by that. A digital broadcasting system in which a plurality of hierarchized data corresponding to each of a plurality of hierarchies is transmitted from a transmitting device to a receiving device using a plurality of segments provided along a frequency direction,
The transmitter is
A transmission frame generation unit that generates a transmission frame composed of data symbols corresponding to each of the plurality of hierarchized data and allocated to each segment corresponding to each of the plurality of hierarchies;
A GI adding unit that adds a guard interval to the transmission frame based on an FFT size of the data symbol and a guard interval ratio;
The receiving device is:
A demodulator that demodulates a radio signal corresponding to at least one layer;
The transmission frame includes a preamble including a control signal indicating an FFT size and a guard interval ratio of the data symbol,
The preamble is individually included for each segment corresponding to each of the plurality of hierarchies,
The demodulator detects the preamble included in a segment corresponding to the at least one layer, and identifies an FFT size and a guard interval ratio of the data symbol based on the control signal included in the detected preamble A digital broadcasting system characterized by this.

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