JP6259632B2 - Digital broadcasting system, receiving device and chip - Google Patents

Description

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

  In ISDB-T (Integrated Services Digital Broadcasting-Terrestrial), which is a terrestrial digital broadcasting system in Japan, SISO (Single Input Single Output) that transmits a signal from one transmitting antenna to one receiving antenna is used (for example, Non-Patent Document 1). In next-generation terrestrial broadcasting, it is desired to realize 2 × 2 MIMO (Multiple Input Multiple Output) that transmits signals from two transmitting antennas to two receiving antennas as a transmission method for realizing large-capacity transmission.

"Transmission standard for digital terrestrial television broadcasting" ARIB STD-B31

  By the way, in a receiving apparatus that exists in an area where signals transmitted from the first transmitting apparatus and the second transmitting apparatus can be received, the transmission signal of the first transmitting apparatus and the transmission signal of the second transmitting apparatus are at the same level. It is assumed that it will be received. In the case where the same signal is transmitted from the first transmitter and the second transmitter at the same frequency, there is a possibility that the reception characteristics of the receiver will deteriorate.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide a digital broadcasting system, a receiving device, and a chip that can suppress deterioration of reception characteristics in the receiving device. To do.

  A first feature is a digital broadcast system including a first transmission device having two transmission antennas and a second transmission device having two transmission antennas, wherein the first transmission device converts a symbol sequence to a first rule. A first pre-encoding unit that outputs a first symbol sequence and a second symbol sequence obtained by encoding by space-time encoding, and encoding the first symbol sequence by space-time encoding according to a second rule A first post-coding unit that generates the first symbol sequence A and generates the second symbol sequence A by encoding the second symbol sequence by space-time coding according to a third rule, The second transmission apparatus includes the first symbol series and the second symbol system obtained by encoding the symbol series by space-time coding according to the first rule. A first pre-coding unit that outputs the first symbol sequence B by encoding the first symbol sequence by the space-time coding of the second rule, and the second symbol sequence as the third symbol sequence The gist of the present invention is to include a second latter encoding unit that generates the second symbol sequence B by encoding by regular space-time encoding.

  The second feature is provided in a digital broadcasting system including a first transmission device having two transmission antennas and a second transmission device having two transmission antennas. From the first transmission device and the second transmission device, A reception device capable of receiving a signal to be transmitted, wherein the first transmission device includes a first symbol sequence and a second symbol sequence obtained by encoding a symbol sequence by space-time coding according to a first rule. Of these, by encoding the first symbol sequence A obtained by encoding the first symbol sequence by space-time encoding of the second rule and the second symbol sequence by encoding of space-time encoding of the third rule The obtained second symbol sequence A is transmitted, and the second transmission device encodes the symbol sequence by the space-time coding of the first rule. Of the first symbol series and the second symbol series obtained by the above, the first symbol series B and the second symbol obtained by encoding the first symbol series by the space-time coding of the second rule Transmitting a second symbol sequence B obtained by encoding the sequence by the space-time coding of the third rule, the first symbol sequence A, the first symbol sequence B, and the second symbol sequence A And a receiving unit that receives the second symbol sequence B, and the first transmission device based on the first symbol sequence A, the first symbol sequence B, the second symbol sequence A, and the second symbol sequence B. And a detection unit that detects a signal transmitted from the second transmission device.

  A third feature is provided in a digital broadcasting system including a first transmission device having two transmission antennas and a second transmission device having two transmission antennas. From the first transmission device and the second transmission device, A chip mounted on a receiving device capable of receiving a signal to be transmitted, wherein the first transmitting device includes a first symbol sequence obtained by encoding a symbol sequence by space-time coding according to a first rule, and Of the second symbol sequences, the first symbol sequence A obtained by encoding the first symbol sequence by the second rule space-time coding and the second symbol sequence by the third rule space-time coding. A second symbol sequence A obtained by encoding is transmitted, and the second transmission device converts the symbol sequence into space-time encoding of the first rule. Of the first symbol series and the second symbol series obtained by encoding the first symbol series, the first symbol series obtained by encoding the first symbol series by space-time coding according to the second rule B and a second symbol sequence B obtained by encoding the second symbol sequence by space-time coding of the third rule, and transmitting the first symbol sequence A, the first symbol sequence B, Based on the receiving unit that receives the second symbol sequence A and the second symbol sequence B, and the first symbol sequence A, the first symbol sequence B, the second symbol sequence A, and the second symbol sequence B And a detection unit that detects a signal transmitted from the first transmission device and the second transmission device.

  According to the present invention, it is possible to provide a digital broadcasting system, a receiving device, and a chip that can suppress deterioration of reception characteristics in the receiving device.

FIG. 1 is a block diagram illustrating a transmission device 10 and a transmission device 20 according to the first embodiment. FIG. 2 is a block diagram illustrating the receiving device 30 according to the first embodiment. FIG. 3 is a diagram illustrating an example of space-time coding according to the first embodiment. FIG. 4 is a diagram illustrating an example of space-time coding according to the first embodiment. FIG. 5 is a diagram illustrating combinations of transformation matrices 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 digital broadcast system according to the embodiment includes a first transmission device having two transmission antennas and a second transmission device having two transmission antennas. The first transmission device includes a first pre-encoding unit that outputs a first symbol sequence and a second symbol sequence obtained by encoding a symbol sequence by space-time coding according to a first rule; and the first symbol A first symbol sequence A is generated by encoding the sequence by a second rule space-time encoding, and a second symbol sequence A is generated by encoding the second symbol sequence by a third rule space-time encoding. And a first latter-stage encoding unit. The second transmission apparatus outputs a first symbol sequence and a second symbol sequence obtained by encoding the symbol sequence by space-time coding of the first rule; Encoding the first symbol sequence by the space-time encoding of the second rule to generate a first symbol sequence B, and encoding the second symbol sequence by the space-time encoding of the third rule And a second subsequent encoding unit that generates the second symbol sequence B.

  In the embodiment, since the space-time code is performed in two stages, it is possible to suppress deterioration of reception characteristics in the reception apparatus. Specifically, the first symbol sequence and the second symbol sequence obtained by the space-time coding of the first rule are the first rear-stage encoding unit provided in the first transmission device and the second rear-stage provided in the second transmission device. Coding into four symbol sequences by cooperation of the encoding unit. As a result, reception characteristics in the receiving device are improved.

[First Embodiment]
(Digital broadcasting system)
Hereinafter, the digital broadcast system according to the first embodiment will be described. FIG. 1 is a block diagram showing a transmission device 10 and a transmission device 20 according to the first embodiment, and FIG. 2 is a block diagram showing a reception device 30 according to the first embodiment. The digital broadcasting system includes a transmission device 10, a transmission device 20, and a reception device 30. A digital broadcasting system can be configured by only the transmission device 10 and the reception device 30. A digital broadcasting system can be configured by only the transmission device 10 and the reception device 30.

  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 corresponding to the next generation terrestrial broadcasting system, a MIMO (Multiple Input Multiple Output) technology and an OFDM (Orthogonal Frequency Division Multiplexing) technology are applied. In the digital broadcasting system, hierarchical data (for example, 1 segment, 13 segments) belonging to a plurality of layers is transmitted from the transmission device 10 to the reception device 30.

  It should be noted that in the first embodiment, the transmission device 10 and the transmission device 20 acquire the same data. The transmission device 10 and the transmission device 20 are not particularly limited, but are provided at positions separated from each other. The frequencies used in the transmission device 10 and the transmission device 20 are the same, and the digital broadcasting system constitutes an SFN (Single Frequency Network).

(Transmitter)
As illustrated in FIG. 1, the transmission apparatus 10 includes an error correction encoding unit 11, a mapping unit 12, a pre-encoding unit 13, a post-encoding unit 14, an OFDM frame configuration unit 15, and an IFFT unit 16. GI adding unit 17 and transmitting antenna 18. Similarly, the transmission device 20 includes an error correction encoding unit 21, a mapping unit 22, a pre-encoding unit 23, a post-encoding unit 24, an OFDM frame configuration unit 25, an IFFT unit 26, and a GI adding unit. 27 and a transmission antenna 28.

  Since the configuration of the transmission device 20 is the same as the configuration of the transmission device 10, the transmission device 10 will be mainly described below.

  The error correction encoding unit 11 adds an error correction code to a predetermined number of bit strings extracted from a bit string constituting externally input data (video data, audio data, etc.), and generates an error correction block of a predetermined length To do.

  The mapping unit 12 maps a predetermined number of bit strings determined according to the modulation multi-level number of the carrier modulation process on the IQ plane. As the carrier modulation processing, for example, 64QAM, 256QAM, 1024QAM or the like that maps an even bit string as one symbol is used. Alternatively, 32QAM, 128QAM, 512QAM, or the like that maps an odd bit string as one symbol may be used as carrier modulation processing.

The pre-stage encoding unit 13 outputs a first symbol sequence and a second symbol sequence obtained by encoding the symbol sequence output from the mapping unit 12 by space-time encoding according to the first rule. Specifically, the upstream encoder 13 encodes the first symbol P ₀ and the second symbol P _{1 for} each block configured by the first symbol P ₀ and the second symbol P ₁ .

  The transformation matrix used in the first rule space-time coding is a transformation matrix selected from the transformation matrix J and the transformation matrix K, or a transformation matrix selected from the transformation matrix L and the transformation matrix M. The transformation matrix J to transformation matrix M are as shown below.

  The transformation matrix J is an Alamouti space-time block coding matrix. In the transformation matrix J, the row indicates a symbol transmitted from each transmission antenna. If the space-time coding is STBC (Space Time Block Coding), the columns in the transformation matrix J indicate symbols transmitted at each transmission time. On the other hand, if the space-time coding is SFBC (Space Frequency Block Coding), in the transformation matrix J, the column indicates a symbol transmitted at each frequency (in OFDM transmission, the number of a carrier constituting the OFDM frame). ing.

  The transformation matrix K is an Alamouti space-time block coding matrix. In the transformation matrix K, the row indicates a symbol transmitted from each transmission antenna. Also, if the space-time coding is STBC (Space Time Block Coding), in the transformation matrix K, the columns indicate symbols transmitted at each transmission time. On the other hand, if the space-time coding is SFBC (Space Frequency Block Coding), in the transformation matrix K, the column indicates a symbol transmitted at each frequency (in OFDM transmission, the number of the carrier constituting the OFDM frame). ing.

  The transformation matrix L is a modified Alamouti space-time block coding matrix. In the transformation matrix L, a row indicates a symbol transmitted from each transmission antenna. In addition, when the space-time coding is STBC (Space Time Block Coding), in the transformation matrix L, columns indicate symbols transmitted at each transmission time. On the other hand, if the space-time coding is SFBC (Space Frequency Block Coding), in the transformation matrix L, the column indicates a symbol transmitted at each frequency (in OFDM transmission, the number of the carrier constituting the OFDM frame). ing.

  The transformation matrix M is a modified Alamouti space-time block coding matrix. In the transformation matrix M, the row indicates a symbol transmitted from each transmission antenna. Also, if the space-time coding is STBC (Space Time Block Coding), in the transformation matrix M, the columns indicate symbols transmitted at each transmission time. On the other hand, if the space-time coding is SFBC (Space Frequency Block Coding), in the transformation matrix M, the column indicates a symbol transmitted at each frequency (in OFDM transmission, the number of a carrier constituting an OFDM frame). ing.

  The subsequent encoding unit 14 includes a subsequent encoding unit 14A and a subsequent encoding unit 14B.

  The post-encoding unit 14A configures an STC encoder in combination with the post-encoding unit 24A of the transmission device 20. Although details will be described later, the encoder configured by the subsequent-stage encoding unit 14A and the subsequent-stage encoding unit 24A is the STC # 1 illustrated in FIG. 3 or FIG. The STC # 1 generates the first symbol sequence A and the first symbol sequence B by encoding the first symbol sequence by space-time coding according to the second rule.

  In other words, the subsequent encoding unit 14A generates the first symbol sequence A by encoding the first symbol sequence output from the preceding encoding unit 13 by space-time encoding according to the second rule. On the other hand, the subsequent encoding unit 24A generates the first symbol sequence B by encoding the first symbol sequence output from the preceding encoding unit 23 by space-time encoding according to the second rule.

  The post-encoding unit 14B configures an STC encoder in combination with the post-encoding unit 24B of the transmission device 20. Although details will be described later, the encoder configured by the subsequent-stage encoding unit 14B and the subsequent-stage encoding unit 24B is the STC # 2 illustrated in FIG. 3 or FIG. The STC # 2 generates the second symbol sequence A and the second symbol sequence B by encoding the second symbol sequence by space-time coding according to the third rule.

  In other words, the subsequent encoding unit 14B generates the second symbol sequence A by encoding the second symbol sequence output from the preceding encoding unit 13 by space-time encoding according to the third rule. On the other hand, the subsequent encoding unit 24B generates the second symbol sequence B by encoding the second symbol sequence output from the preceding encoding unit 23 by space-time encoding according to the third rule.

In the first embodiment, the post-coding unit 14A and the post-coding unit 14B, for each block configured by the first symbol P ₀ and the second symbol P ₁ , apply the first symbol P ₀ and the second symbol P ₁ . Encode.

  The transformation matrix used in the space-time coding of the second rule and the space-time coding of the third rule is a transformation matrix selected from the transformation matrix J and the transformation matrix K, or the transformation matrix L and the transformation matrix M. A transformation matrix selected from. The transformation matrix J to transformation matrix M are as described above.

  In the transformation matrix J to transformation matrix M, the row indicates a symbol transmitted from each transmission device. Also, if the space-time coding is STBC (Space Time Block Coding), in the transformation matrix J to transformation matrix M, the columns indicate symbols transmitted at each transmission time. On the other hand, if the space-time coding is SFBC (Space Frequency Block Coding), in the transformation matrix J to transformation matrix M, a column is transmitted at each frequency (in OFDM transmission, the number of the carrier constituting the OFDM frame). Symbol.

  The OFDM frame configuration unit 15 includes an OFDM frame configuration unit 15A and an OFDM frame configuration unit 15B. The OFDM frame configuration unit 15A is an OFDM frame (transmission frame) defined by a predetermined number of subcarriers (frequency axis) and a predetermined number of symbols (time axis) based on the symbol sequence output from the subsequent encoding unit 14A. ) Is generated. On the other hand, the OFDM frame configuration unit 15B is an OFDM frame defined by a predetermined number of subcarriers (frequency axis) and a predetermined number of symbols (time axis) based on the symbol sequence output from the subsequent encoding unit 14B. (Transmission frame) is generated.

  An OFDM frame (transmission frame) includes data symbols corresponding to data signals, control symbols corresponding to control signals, pilot symbols, and the like. The control signal is, for example, a TMCC (Transmission and Multiplexing Configuration Control) signal, an AC (Auxiliary Channel) signal, or the like. For example, the TMCC signal includes a signal indicating transmission parameters (modulation method, number of segments, coding rate, etc.) of a plurality of layers, and a synchronization signal for synchronizing an OFDM frame (transmission frame).

  The IFFT unit 16 includes an IFFT unit 16A and an IFFT unit 16B. The IFFT unit 16A performs inverse Fourier transform on the OFDM frame output from the OFDM frame configuration unit 15A. On the other hand, IFFT unit 16B performs inverse Fourier transform on the OFDM frame output from OFDM frame configuration unit 15B.

  The GI adding unit 17 includes a GI adding unit 17A and a GI adding unit 17B. The GI adding unit 17A adds a GI (Gurred Interval) to the signal output from the IFFT unit 16A. On the other hand, the GI adding unit 17B adds a GI (Guard Interval) to the signal output from the IFFT unit 16B.

  The transmission antenna 18 includes a transmission antenna 18A and a transmission antenna 18B. The transmission antenna 18A transmits the signal (transmission signal corresponding to the first symbol sequence A) output from the GI adding unit 17A. On the other hand, the transmission antenna 18B transmits a signal (transmission signal corresponding to the second symbol sequence A) output from the GI addition unit 17B. For example, the transmission antenna 18A transmits a horizontally polarized signal, and the transmit antenna 18B transmits a vertically polarized signal, for example.

(Receiver)
As illustrated in FIG. 2, the reception device 30 includes a reception antenna 31, a GI removal unit 32, an FFT unit 33, a transmission path response estimation unit 34, a transmission signal detection unit 35, a carrier demodulation unit 36, an error A correction code decoding unit 37.

  The receiving antenna 31 includes a receiving antenna 31A and a receiving antenna 31B. The receiving antenna 31A receives a horizontally polarized signal. For example, when the transmitting antenna 18A and the transmitting antenna 28A transmit a horizontally polarized signal, the receiving antenna 31A corresponds to the signal transmitted from the transmitting antenna 18A and the transmitting antenna 28A (that is, the first symbol sequence A). A transmission signal and a transmission signal corresponding to the first symbol sequence B) are received. On the other hand, the receiving antenna 31B receives a vertically polarized signal. For example, when the transmission antenna 18B and the transmission antenna 28B transmit vertically polarized signals, the reception antenna 31B corresponds to the signal transmitted from the transmission antenna 18B and the transmission antenna 28B (that is, the second symbol sequence A). A transmission signal and a transmission signal corresponding to the second symbol sequence B) are received. Both the receiving antenna 31A and the receiving antenna 31B may receive signals having the same polarization.

  The GI removal unit 32 includes a GI removal unit 32A and a GI removal unit 32B. The GI removal unit 32A removes a GI (Gurred Interval) from the signal received by the reception antenna 31A. On the other hand, the GI removal unit 32B removes GI (Gurred Interval) from the signal received by the reception antenna 31B.

  The FFT unit 33 includes an FFT unit 33A and an FFT unit 33B. The FFT unit 33A performs a Fourier transform on the signal output from the GI removal unit 32A. On the other hand, the FFT unit 33B performs a Fourier transform on the signal output from the GI removal unit 32B.

  The transmission channel response estimation unit 34 extracts a known pilot carrier included in the signal output from the FFT unit 33A, and estimates the transmission channel response of the pilot carrier according to the extracted pilot carrier. Similarly, the transmission path response estimation unit 34 extracts a known pilot carrier included in the signal output from the FFT unit 33B, and estimates the transmission path response of the pilot carrier according to the extracted pilot carrier.

  The transmission signal detection unit 35 estimates a symbol included in the signal output from the FFT unit 33 according to the transmission path response estimated by the transmission path response estimation unit 34.

  The carrier demodulation unit 36 performs carrier demodulation processing on the symbols output from the transmission signal detection unit 35. For example, the carrier demodulation unit 36 calculates a transmission bit string or an LLR (log likelihood ratio) corresponding to the transmission bit string from the position of the symbol output from the transmission signal detection unit 35.

  The error correction code decoding unit 37 extracts an error correction block having a predetermined length from the transmission bit string output from the carrier demodulation unit 36 or the LLR corresponding to the transmission bit string, and performs error correction of the error correction block.

(Space-time coding)
In the following, the space-time coding according to the first embodiment will be described. 3 to 5 are diagrams for explaining an example of space-time coding according to the first embodiment.

The digital broadcasting system shown in FIG. 3 and FIG. 4, three encoders (STC # 0, STC # 1 , STC # 2) is provided, three encoder first symbol _{P 0} and the for each block composed of 2 symbols _{P 1,} a first symbol _{P 0} and the second symbol _{P 1} encodes.

  Here, STC # 0 is a pre-encoding unit 13 provided in the transmission apparatus 10 or a pre-encoding unit 23 provided in the transmission apparatus 20. STC # 1 is an encoder configured by a rear-stage encoding unit 14A provided in the transmission apparatus 10 and a rear-stage encoding unit 24A provided in the transmission apparatus 20. STC # 2 is an encoder configured by a rear-stage encoding unit 14B provided in the transmission apparatus 10 and a rear-stage encoding unit 24B provided in the transmission apparatus 20.

  Here, the STC # 0 generates a first symbol sequence and a second symbol sequence by encoding a symbol sequence by space-time encoding according to the first rule. The STC # 1 generates the first symbol sequence A and the first symbol sequence B by encoding the first symbol sequence by space-time coding according to the second rule. The STC # 2 generates the second symbol sequence A and the second symbol sequence B by encoding the second symbol sequence by space-time coding according to the third rule.

  Here, the latter-stage encoding unit 14A described above outputs the first symbol series A obtained by encoding the first symbol series with a space-time code, and the latter-stage encoding unit 14B outputs the second symbol series in time. A second symbol sequence A obtained by encoding with a spatial code is output. On the other hand, the latter-stage encoding unit 24A described above outputs the first symbol series B obtained by encoding the first symbol series using a space-time code, and the latter-stage encoding unit 24B converts the second symbol series into the time. A second symbol sequence B obtained by encoding with a spatial code is output.

  Here, the transformation matrix used in the space-time coding of the first rule, the space-time coding of the second rule, and the space-time coding of the third rule was selected from the transformation matrix J and the transformation matrix K. The transformation matrix or a transformation matrix selected from the transformation matrix L and the transformation matrix M. The transformation matrix J to transformation matrix M are as described above.

As shown in FIG. 3, when STBC is used for space-time coding, STC # 0 encodes a symbol sequence (S _0,0 , S _0,1 ) with a transformation matrix M, for example, A first symbol sequence (S _0,0 , S _0,1 ) and a second symbol sequence (S _0,1 ^* , -S _0,0 ^* ) arranged in the direction are generated. The STC # 1 encodes the first symbol sequence (S _0,0 , S _0,1 ) using the transformation matrix M and arranges the first symbol sequence A (S _0,0 , S _0,1 ) in the time axis direction. And the first symbol sequence B (S _0,1 ^* , -S _0,0 ^* ) is generated. The STC # 2 encodes the second symbol sequence (S _0,1 ^* , −S _0,0 ^* ) with the transformation matrix M, so that the second symbol sequence A (S _0,1 ^*) arranged in the time axis direction ^. , −S _0,0 ^* ) and the second symbol sequence B (−S _0,0 , −S _0,1 ).

As shown in FIG. 4, when using SFBC as space-time coding, STC # 0 encodes, for example, a symbol sequence (S _0,0 , S _0,1 ) with a transformation matrix M, A first symbol sequence (S _0,0 , S _0,1 ) and a second symbol sequence (S _0,1 ^* , -S _0,0 ^* ) arranged in the direction are generated. The STC # 1 encodes the first symbol sequence (S _0,0 , S _0,1 ) with the transformation matrix M and arranges the first symbol sequence A (S _0,0 , S _0,1 ) in the frequency axis direction. And the first symbol sequence B (S _0,1 ^* , -S _0,0 ^* ) is generated. The STC # 2 encodes the second symbol sequence (S _0,1 ^* , −S _0,0 ^* ) with the transformation matrix M, whereby the second symbol sequence A (S _0,1 ^*) arranged in the frequency axis direction ^. , −S _0,0 ^* ) and the second symbol sequence B (−S _0,0 , −S _0,1 ).

3 and 4, the first symbol sequence A (S _0,0 , S _0,1 ) and the second symbol sequence A (S _0,1 ^* , − S _0,0 ^* ) are transmitted from the transmission device 10. Is done. The first symbol sequence B (S _0,1 ^* , -S _0,0 ^* ) and the second symbol sequence B (-S _0,0 , -S _0,1 ) are transmitted from the transmission device 20.

  In the first embodiment, one of the transmission signal corresponding to the first symbol sequence A and the transmission signal corresponding to the second symbol sequence A is transmitted by the first polarization (for example, horizontal polarization). The other transmission signal is preferably transmitted by the second polarization (for example, vertical polarization). On the other hand, one of the transmission signals corresponding to the first symbol sequence B and the transmission signal corresponding to the second symbol sequence B is transmitted by the first polarization (horizontal polarization), and the other transmission signal. Is preferably transmitted by the second polarization (for example, vertical polarization).

  In the first embodiment, the combinations shown in FIG. 5 are considered as combinations of transform matrices used in each encoder. In such a case, the transformation matrix (STC # 0) for the first rule, the spacetime coding for the second rule (STC # 1), and the space-time coding for the third rule (STC # 1). STC # 2) is preferably a transformation matrix selected from the transformation matrix L and the transformation matrix M (that is, the transformation matrix of Modified Alamouti).

(Function and effect)
In the first embodiment, since the space-time code is performed in two stages, it is possible to suppress deterioration of reception characteristics in the reception device 30. Specifically, the first symbol series and the second symbol series obtained by the space-time coding according to the first rule are transmitted from the subsequent encoding unit 14 provided in the transmission apparatus 10 and the subsequent encoding unit 24 provided in the transmission apparatus 20. By the cooperation, it is encoded into four symbol sequences. Thereby, the reception characteristic in the receiving device 30 is improved.

[Modification 1]
Hereinafter, Modification Example 1 of the first embodiment will be described. In the first embodiment, the case where the reception device 30 includes the two reception antennas 31 has been described. However, the embodiment is not limited to this, and the receiving device 30 may have one receiving antenna 31.

  For example, when the received symbol is y, the received signals at time t and time t + 1 can be expressed as follows.

Here, h ₁₁ , h ₁₂ , h ₁₃ , and h ₁₄ are transmission path responses between four transmission antennas and one reception antenna. Further, the case where the transformation matrix M is used in STC # 0, the transformation matrix L is used in STC # 1, and the transformation matrix M is used in STC # 2.

  When the above formula is modified, the following formula is obtained.

    When the variables in the above formula are replaced, the following formula is obtained.

    Here, by multiplying both sides of equation (1) by A *, taking the complex conjugate of both sides of equation (2) and multiplying by B, the following equation is obtained.

Symbols S ₀ and S ₁ can be detected by subtracting equation (4) from equation (3).

Thus, the receiving antenna 31 to the receiving apparatus 30 has is be one, it is possible to detect the symbols S ₀ and S _1.

[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.

  Although not particularly specified in the embodiment, the above-described embodiment may be applied not only to a system using the MIMO (Multiple Input Multiple Output) technique but also to a system using the MISO (Multiple Input Single Output) technique. Good.

  Although not specifically mentioned in the embodiment, a program for causing a computer to execute each process performed by the transmission device 10, the transmission device 20, and the reception device 30 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 10, the transmission device 20, and the reception device 30 and a processor that executes the program stored in the memory may be provided.

  DESCRIPTION OF SYMBOLS 10,20 ... Transmission apparatus, 11, 21 ... Error correction encoding part, 12, 22 ... Mapping part, 13, 23 ... Pre-stage encoding part, 14, 24 ... Subsequent encoding part, 15, 25 ... OFDM frame structure part 16, 26 ... IFFT unit, 17, 27 ... GI adding unit, 18, 28 ... transmitting antenna, 30 ... receiving device, 31 ... receiving antenna, 32 ... GI removing unit 33 ... FFT unit, 34 ... Transmission path response estimation unit, 35 ... Transmission signal detection unit, 36 ... Carrier demodulation unit, 37 ... Error correction code decoding unit

Claims (6)

A digital broadcasting system comprising a first transmission device having two transmission antennas and a second transmission device having two transmission antennas,
The first transmitter is
A first pre-encoding unit that outputs a first symbol sequence and a second symbol sequence obtained by encoding the symbol sequence by space-time coding of the first rule;
A first symbol sequence A is generated by encoding the first symbol sequence by a second rule space-time encoding, and a second symbol sequence A is generated by encoding the second symbol sequence by a third rule space-time encoding. A first latter encoding unit that generates a two-symbol sequence A,
The second transmitter is
A second pre-encoding unit that outputs the first symbol sequence and the second symbol sequence obtained by encoding the symbol sequence by space-time encoding of the first rule;
Encoding the first symbol sequence by the space-time encoding of the second rule to generate a first symbol sequence B, and encoding the second symbol sequence by the space-time encoding of the third rule And a second latter-stage encoding unit that generates the second symbol series B. Of the transmission signal corresponding to the first symbol sequence A and the transmission signal corresponding to the second symbol sequence A, one transmission signal is transmitted by the first polarization, and the other transmission signal is the second polarization. Sent by
Of the transmission signal corresponding to the first symbol sequence B and the transmission signal corresponding to the second symbol sequence B, one transmission signal is transmitted by the first polarization, and the other transmission signal is the second polarization. The digital broadcasting system according to claim 1, wherein the digital broadcasting system is transmitted by: The space-time coding of the first rule, the space-time coding of the second rule, and the space-time coding of the third rule are performed for each block constituted by the first symbol P0 and the second symbol P1. Space-time coding for coding the first symbol P0 and the second symbol P1,
The transformation matrix used in the first rule space-time coding, the second rule space-time coding, and the third rule space-time coding was selected from the transformation matrix J and the transformation matrix K. A transformation matrix or a transformation matrix selected from the transformation matrix L and the transformation matrix M;
The transformation matrix J to the transformation matrix M are:

The digital broadcasting system according to claim 1, wherein:   The transformation matrix used in the first rule space-time coding, the second rule space-time coding, and the third rule space-time coding is selected from the transformation matrix L and the transformation matrix M. 4. The digital broadcasting system according to claim 3, wherein the digital broadcasting system is a transformed matrix. Provided in a digital broadcasting system including a first transmission device having two transmission antennas and a second transmission device having two transmission antennas, and receives signals transmitted from the first transmission device and the second transmission device A possible receiving device,
The first transmission device converts the first symbol sequence from the first symbol sequence and the second symbol sequence obtained by encoding the symbol sequence by the first rule space-time coding to the second rule space-time. Transmitting the first symbol sequence A obtained by encoding by encoding and the second symbol sequence A obtained by encoding the second symbol sequence by space-time encoding of the third rule,
The second transmission apparatus converts the first symbol sequence from the first symbol sequence and the second symbol sequence obtained by encoding the symbol sequence by space-time coding according to the first rule. A first symbol sequence B obtained by encoding with two-rule space-time coding and a second symbol sequence B obtained by coding the second symbol sequence with the third-rule space-time coding Sending
A receiving unit for receiving the first symbol sequence A, the first symbol sequence B, the second symbol sequence A, and the second symbol sequence B;
Based on the first symbol sequence A, the first symbol sequence B, the second symbol sequence A, and the second symbol sequence B, signals transmitted from the first transmission device and the second transmission device are detected. A receiving apparatus comprising: a detection unit. Provided in a digital broadcasting system including a first transmission device having two transmission antennas and a second transmission device having two transmission antennas, and receives signals transmitted from the first transmission device and the second transmission device A chip mounted on a possible receiving device,
The first transmission device converts the first symbol sequence from the first symbol sequence and the second symbol sequence obtained by encoding the symbol sequence by the first rule space-time coding to the second rule space-time. Transmitting the first symbol sequence A obtained by encoding by encoding and the second symbol sequence A obtained by encoding the second symbol sequence by space-time encoding of the third rule,
The second transmission apparatus converts the first symbol sequence from the first symbol sequence and the second symbol sequence obtained by encoding the symbol sequence by space-time coding according to the first rule. A first symbol sequence B obtained by encoding with two-rule space-time coding and a second symbol sequence B obtained by coding the second symbol sequence with the third-rule space-time coding Sending
A receiving unit for receiving the first symbol sequence A, the first symbol sequence B, the second symbol sequence A, and the second symbol sequence B;
Based on the first symbol sequence A, the first symbol sequence B, the second symbol sequence A, and the second symbol sequence B, signals transmitted from the first transmission device and the second transmission device are detected. A chip comprising a detector.

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