JP7054334B2 - Transmitter, receiver and chip - Google Patents

Description

The present invention relates to a transmitting device, a receiving device and a chip, and more particularly to a transmitting device, a receiving device and a chip for transmitting and receiving a signal including a pilot signal (pilot carrier).

The ISDB-T (Integrated Services Digital Broadcasting-Terrestrial) system, which is the current terrestrial digital broadcasting system in Japan, uses OFDM (Orthogonal Frequency Division Multiplexing) as the modulation method and uses a predetermined frequency of the OFDM frame. A pilot signal is assigned to the carrier symbol, and the receiving side is configured to calculate the transmission line characteristic (transmission line response) from the reception state of this pilot signal so that the data can be received accurately (Non-Patent Document 1). ..

On the other hand, in the next-generation terrestrial digital broadcasting system (hereinafter, also referred to as the next-generation terrestrial transmission system) that assumes super high-definition broadcasting by terrestrial broadcasting, various modulation methods and new transmission methods are used to expand the transmission capacity. In particular, a MIMO (Multi-Input Multi-Output) transmission method that uses multiple antennas on both the transmitting side and the receiving side, and a MIMO (Multi-Input Multi-Output) transmission method that uses multiple antennas on the transmitting side and one antenna on the receiving side. A MISO (Multi-Input Single-Output) transmission method using the above is being energetically studied.

In the MIMO transmission method and the MISO transmission method, it is necessary to individually estimate the transmission line characteristics from each transmitting antenna to the receiving antenna as accurately as possible. Therefore, using the orthogonalized pilot signal, the pilot signal is made different for each OFDM signal transmitted from each transmitting antenna, and the characteristics of each transmission line are calculated from the received signal. Hereinafter, the principle thereof will be briefly described by taking a 2 × 2 MIMO transmission method having two transmitting antennas and two receiving antennas as an example.

A known SP (Scattered Pilot) signal is used to individually estimate the transmission path characteristics of the signal coming from each transmitting antenna. The transmitting antenna is Tx1 and Tx2, and the receiving antenna is Rx1 and Rx2. In order to make the two series of SP signals transmitted from Tx1 and Tx2 different, a part of the SP signals transmitted from Tx2 is code-inverted, and an SP signal orthogonal to the SP signal of Tx1 is transmitted.

FIG. 5 shows the arrangement of the conventional pilot signal in each OFDM signal transmitted from the two systems of Tx1 and Tx2. The arrangement of the SP signal on the Tx1 side shown in FIG. 5A is the same as that of ISDB-T, and the SP signal is arranged every 12 carriers in the carrier (frequency) direction and every 4 symbols in the symbol (time) direction. Has been done. In the figure, the white squares indicate the data symbols, and the hatched squares in the diagonal direction indicate the normal (coefficient + 1) SP signal. A continuous CP (Continual Pilot) signal is arranged on the carrier at the end of the OFDM frame.

FIG. 5B shows the arrangement of the pilot signal on the Tx2 side. The positions of the SP signal and the CP signal are the same as those of Tx1, but every other SP signal is code-inverted. In FIG. 5B, the diagonal hatch squares show the normal (coefficient + 1) SP signal, and the cross-hatched squares show the sign-inverted (coefficient-1 multiplied) SP signal. The same continuous CP signal as Tx1 is arranged on the carrier at the end of the OFDM frame.

In the receiving antennas Rx1 and Rx2, since the signals transmitted from the transmitting antennas Tx1 and Tx2 are mixed and received, the SP signal is also received as a mixture of the SP signals of Tx1 and Tx2. Therefore, the SP signal and the SP signal adjacent thereto are combined to individually estimate the transmission line characteristics from Tx1 and the transmission line characteristics from Tx2. Here, the transmission line characteristics are estimated by combining SP signals adjacent in the frequency direction. It should be noted that the calculation can be performed in the same manner whether the SP signals adjacent in the time direction are combined or the SP signals adjacent in the diagonal direction are combined.

Since the SP signals adjacent to each other in the frequency direction are separated by 12 carriers in the frequency (carrier) direction in the same symbol line, the SP signals on the Tx1 side are set to P1 (l, k) and P1 (l, k + 12). If the SP signals on the Tx2 side are P2 (l, k) and P2 (l, k + 12), only P2 (l, k + 12) is code-inverted, so that equation (1) holds. Here, l is a symbol number and k is a carrier number.

Assuming that the transmission path characteristic (transmission path response) from the transmission antenna Tx1 to the reception antenna Rx1 is h11 and the transmission path characteristic (transmission path response) from the transmission antenna Tx2 to the reception antenna Rx1 is h12, the reception signal R1 (l, k) and R1 (l, k + 12) are given by the following equation (2).

Here, assuming that the frequency interval between the carrier k and the carrier (k + 12) is narrow and the transmission line characteristics are the same, h11 (l, k) = h11 (l, k + 12), h12 (l, k) = h12. Since (l, k + 12) holds, the following equation (3) is derived from this assumption and equations (1) and (2).

By solving the equation (3), the transmission line characteristics for the receiving antenna Rx1 can be obtained by the following equation (4).

Similarly, the transmission line characteristics from the transmitting antennas Tx1 and Tx2 to the receiving antenna Rx2 can be obtained. (Non-Patent Document 2, Patent Document 1)

Japanese Patent No. 5291584

"Transmission method of terrestrial digital television broadcasting" standard, ARIB STD-B31, Association of Radio Industries and Businesses Zenichi Naruki, et al., "MIMO-OFDM Transmission Technology for Mobile Reception Using Spatio-Temporal Coding", NHK Science & Technical Research Laboratories R & D, Broadcasting Technology Research Laboratories, Japan Broadcasting Corporation, November 2012, No. 136, pp. 41-49

In this way, the characteristics of each transmission line have been estimated using SP signals so far, but it is assumed that the next-generation terrestrial transmission method will adopt a modulation method with a large number of modulation values. In order to accurately demap the received signal, it is required to estimate the transmission line characteristics more accurately.

In order to accurately estimate the transmission line characteristics, it is better to increase the SP signal, but if the SP signal is increased in a certain frame configuration, the data carrier will decrease, so the SP signal will be increased. This is not desirable from the viewpoint of increasing the transmission capacity.

Therefore, an object of the present invention made in view of the above problems is a transmission device capable of more accurately estimating a transmission line characteristic in a MIMO transmission method or a MISO transmission method without increasing the SP signal. , To provide a receiver and a chip.

In order to solve the above problems, the transmission device according to the present invention is provided with a plurality of transmission systems, and is distributed and arranged at predetermined symbol (time) intervals and carrier (frequency) intervals in the transmission device that transmits OFDM signals. The SP includes a first and second OFDM frame component constituting an OFDM frame including a SP signal and a CP signal continuously arranged on a predetermined frequency carrier, and the SP is provided in at least one OFDM frame component. The first coefficient and the second coefficient are alternately multiplied in the symbol (time) direction and the carrier (frequency) direction with respect to the signal, and the symbol (time) in which the SP signal is arranged with respect to the CP signal. ) An OFDM frame in which the first coefficient and the second coefficient are alternately multiplied for each number corresponding to the same predetermined symbol (time) interval as the interval is configured , and the OFDM frame component is composed of at least one of the OFDM frame components. The OFDM frame is characterized in that the relationship (periodicity) between the first coefficient and the second coefficient in the SP signal is maintained also in the CP signal .

Further, it is desirable that the transmission device has a first coefficient and a second coefficient of +1 and -1, and multiplication is performed in one OFDM frame component and no multiplication is performed in the other OFDM frame component.

Further, in the transmission device, the first coefficient and the second coefficient are +1 and 0, and the coefficients to be multiplied by the SP signal or CP signal at the corresponding positions in the first and second OFDM frame components are opposite. Is desirable.

In order to solve the above problems, the chip according to the present invention is mounted on a transmission device and is continuously arranged on a predetermined frequency carrier and an SP signal distributed at predetermined symbol (time) intervals and carrier (frequency) intervals. A chip that generates an OFDM frame containing a CP signal that is specifically arranged, and is an SP that is obtained by alternately multiplying at least a first coefficient and a second coefficient in the symbol (time) direction and the carrier (frequency) direction. A CP signal obtained by alternately multiplying a first coefficient and a second coefficient for each number corresponding to the signal and the symbol (time) interval of the SP signal is included, and the first coefficient and the first coefficient in the SP signal are included. It is characterized by creating an OFDM frame in which the relationship (periodicity) of the coefficients of 2 is maintained even in the CP signal .

In order to solve the above problems, the receiving device according to the present invention is a receiving device that receives OFDM signals transmitted from a plurality of transmitting systems, and the OFDM signals transmitted from at least one transmitting system are in the symbol (time) direction. And the SP signal obtained by alternately multiplying the first coefficient and the second coefficient in the carrier (frequency) direction, and the first coefficient and the second coefficient for each number corresponding to the symbol (time) interval of the SP signal. A CP signal obtained by alternately multiplying the coefficients is included, and the relationship (periodicity) between the first coefficient and the second coefficient in the SP signal is maintained in the CP signal, and the SP signal and the SP signal are maintained. It is characterized in that the transmission line characteristics from the plurality of transmission systems are estimated by combining CP signals.

Further, it is desirable that the receiving device uniformly processes the processing for estimating the transmission line characteristics by regarding the CP signal as an SP signal.

In order to solve the above problems, the chip according to the present invention is a chip mounted on a receiving device, and at least the first coefficient and the second coefficient are alternated in the symbol (time) direction and the carrier (frequency) direction. The SP signal multiplied by the above and the CP signal obtained by alternately multiplying the first coefficient and the second coefficient for each number corresponding to the symbol (time) interval of the SP signal are included. The relationship (periodicity) between the coefficient 1 and the second coefficient is maintained in the CP signal, and the OFDM signal is processed, and the SP signal and the CP signal are combined and transmitted from a plurality of transmission systems. It is characterized by estimating road characteristics.

According to the transmitting device, the receiving device and the chip in the present invention, in the MIMO transmission method or the MISO transmission method, the transmission line characteristics can be estimated more accurately without increasing the SP signal.

Further, according to the receiving device and the chip in the present invention, the CP signal can be regarded as an SP signal and uniformly processed, so that the efficiency of signal processing can be improved.

It is a block diagram which shows an example of the transmission device of this invention. It is a figure which shows the example of the pilot (SP, CP) signal in the code inversion method of this invention. It is a figure which shows the example of the pilot (SP, CP) signal in the null system of this invention. It is a block diagram which shows an example of the receiving apparatus of this invention. It is a figure which shows the example of the pilot (SP, CP) signal in the conventional code inversion method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
The transmission device as the first embodiment of the present invention will be described. FIG. 1 is a block diagram showing an example of a transmission device. This transmission device 10 is a so-called OFDM transmission device, and is an error correction coding unit 11, a mapping unit 12, a spatiotemporal coding unit 13, an OFDM frame configuration unit 14, 15, a pilot signal generation unit 16, and an IFFT (Inverse Fast Fourier). Transform) units 17 and 18 and transmission antennas Tx1 and Tx2 are provided. The transmission device 10 of the present invention performs a MIMO transmission method or a MISO transmission method, and the OFDM frame components 14, 15, the OFDM units 17, 18 and the transmission antennas Tx1 and Tx2 correspond to at least the transmission system. It has two systems.

The error correction coding unit 11 inputs data transmitted by the transmission device 10 (for example, TS (transport stream) of a video signal), performs error correction coding processing, and converts the encoded data into a mapping unit 12. Output to. As the error correction code, an RS code, a convolutional code, a turbo code, an LDPC (Low Density Parity Check) code, or the like is used. When performing error correction coding processing, processing such as energy diffusion and interleaving may be performed as necessary.

The mapping unit 12 takes the data encoded by the error correction coding unit 11 as an input, maps it to the IQ plane by a predetermined modulation method, and performs data carrier modulation. The mapped data is output to the space-time coding unit 13. As the modulation method, in addition to QPSK (Quadrature Phase shift Keying), 16QAM (Quadrature Amplitude Modulation) and 64QAM used in ISDB-T, 256QAM, 1024QAM, 4096QAM and the like may be used as the next-generation terrestrial transmission method. ..

The spatiotemporal coding unit 13 takes the data mapped by the mapping unit 12 as an input, performs spatiotemporal coding processing, divides the spatiotemporal coded data into two systems, and divides the spatiotemporal coded data into two systems, and the OFDM frame configuration unit 14 of each transmission system. , 15 is output. As the space-time coding process, for example, space-time block coding (STBC: Space Time Block Coding) or space frequency block code (SFBC: Space Frequency Block Coding) is used.

The OFDM frame components (first and second OFDM frame components) 14 and 15 receive the data spatiotemporally coded by the spatiotemporal coding unit 13 as inputs, and the pilot signal (pilot carrier) and TMCC (pilot carrier) and TMCC ( Transmission and Multiplexing Configuration Control (control information carrier), etc. are added to configure an OFDM transmission frame. The OFDM frame components 14 and 15 are provided for each transmission system, and the generated OFDM frame signal is output to the OFDM units 17 and 18 of each system. The pilot signal (SP signal, CP signal) is input from the pilot signal generation unit 16, and the TMCC is generated and input by the TMCC generation unit (not shown) based on various transmission parameters. Each OFDM frame generated by OFDM frame components 14 and 15 will be described later. The process of multiplying the pilot signal described later by a predetermined coefficient may be performed by the OFDM frame component units 14 and 15, or may be performed by the pilot signal generation unit 16.

The pilot signal generation unit 16 generates a pilot signal (SP signal, CP signal) and outputs it to the OFDM frame configuration units 14 and 15. The pilot signal is, for example, a BPSK (Binary Phase shift Keying) associated with the Wi corresponding to the carrier number i of the OFDM segment with respect to the output Wi of the PRBS (Pseudo-random bit sequence) generating circuit. ) Generated as a signal. The process of multiplying the pilot signal to be described later by a coefficient may be performed by the pilot signal generation unit 16, and the SP signal and the CP signal obtained by multiplying the OFDM frame configuration unit 14 and the OFDM frame configuration unit 15 by the coefficient may be performed. May be supplied. It is technically equivalent regardless of whether the OFDM frame component units 14 and 15 and the pilot signal generation unit 16 perform the multiplication process.

The OFDM units 17 and 18 receive the OFDM frame signals output from the OFDM frame components 14 and 15 as inputs, perform inverse fast Fourier transform on the OFDM signals in the frequency domain, and generate the OFDM signals in the time domain. After that, although not shown, GI (guard interval) is added to perform processing such as frequency conversion of the baseband frequency to RF (Radio Frequency) of a predetermined frequency band, and each OFDM signal is transmitted for each transmission system. It is transmitted as a broadcast wave via the antennas Tx1 and Tx2.

Each OFDM frame generated by OFDM frame components 14 and 15 will be described with reference to the drawings. FIG. 2 is an example of using an orthogonal pilot signal generated by the sign inversion method. Here, the layout of the pilot carrier in the existing terrestrial digital broadcasting is used as it is, and the explanation is based on an example in which the transmission frame is configured by the data carrier, the pilot carrier, etc., but the layout of the pilot signal is not limited to this. not.

FIG. 2A shows an example of the arrangement of the data symbol and the pilot signal generated by the OFDM frame component 14 of the first transmission system (sometimes referred to as the first system). When the carrier interval after temporal interpolation is Dx and the symbol interval is Dy, the figure is an example of Dx = 3 and Dy = 4. In the next-generation terrestrial transmission system, a large number of pilot signal arrangements (combinations of Dx and Dy) are prepared and can be selected. The arrangement of pilot signals can be specified for each layer.

In the OFDM frame of FIG. 2A, SP signals are arranged every 12 carriers in the carrier (frequency) direction and every 4 symbols in the symbol (time) direction. In the line shifted by 1 symbol in the symbol (time) direction, the SP signal is arranged with a Dx (3 carrier) shift in the carrier (frequency) direction from the previous line. Further, a continuous CP (Continual Pilot) signal is arranged on the carrier at the end (right end) of the OFDM frame. Similar to FIG. 5, the white squares represent data symbols and the diagonal hatch squares represent normal (coefficient + 1 multiplied) pilot signals.

On the other hand, the OFDM frame component 15 of the second transmission system (sometimes referred to as the second system) uses the same pilot carrier arrangement as the OFDM frame of the first system, but inverts the code of the pilot carrier at a predetermined position. (Phase inversion) is performed to form a transmission frame. That is, the pilot signal of the 2nd system is assumed to be the pilot signal of the 1st system multiplied by a coefficient +1 or -1.

FIG. 2B shows an example of the arrangement of the data symbols and pilot signals of the second system. In the figure, the white squares indicate the data symbols, the diagonal hatching squares indicate the normal (1 system pilot signal multiplied by the coefficient +1) pilot signal, and the cross-hatch squares indicate the sign inversion (1 system). The pilot signal obtained by multiplying the pilot signal of (1) by the coefficient (1) is shown. The pilot signal arrangement of the OFDM frame in FIG. 2B is the same as the pilot signal arrangement of the 1 system, and the SP signal is every 12 carriers in the carrier (frequency) direction and every 4 carriers in the symbol (time) direction. In the line shifted by one symbol in the symbol (time) direction, the SP signal is arranged Dx shifted in the carrier (frequency) direction from the previous line.

In the figure, the carrier symbol at the beginning (first row) and left end (first column) of the OFDM frame is set to normal (multiply by coefficient + 1), and the symbol in the second row and fourth column is inverted (multiply by coefficient -1). Then, the symbol in the third row and the seventh column is set to normal (multiply by the coefficient + 1), and the symbol in the fourth row and the tenth column is inverted (multiplied by the coefficient -1). Then, the carrier-symbol space (4 rows and 12 columns) including the carriers at the beginning and the left end of the OFDM frame is used as a basic block, and the reference numerals are alternately inverted and repeated in the carrier direction and the symbol direction in basic block units. As a result, as shown in FIG. 2B, the SP signals are alternately phase-inverted in the symbol direction, the carrier direction, and the diagonal direction.

Further, in the present invention, as the CP signal, a pilot signal orthogonal to each other by the sign inversion method is used. In FIG. 2B, for the CP signal arranged on the carrier at the end (right end) of the OFDM frame, the Dy symbols from the beginning of the OFDM frame are usually (multiplied by the coefficient + 1), and the next Dy symbols are used. The symbols are inverted (multiplied by the coefficient -1), and then the coefficient is switched for each Dy symbol. In other words, the sign of the CP signal is determined so as to maintain the sign inversion relationship (periodicity) of the SP signal. This makes it possible to use the CP signal as a system 2 SP signal.

Looking at the symbol at the beginning (first line) of FIG. 2B, the CP signal (+1) at the right end and the SP signal (-1) on the left side of the 12 carriers from the right end are adjacent to each other in the frequency direction at predetermined intervals. The relationship is the same as the SP signal, and the transmission line characteristics can be estimated by combining the CP signal and the SP signal. Looking only at the rightmost column, the CP signal (+1) at the beginning and the CP signal (-1) under the Dy (= 4) symbol from the beginning are related to the SP signals adjacent to each other in the time direction at predetermined intervals. They are the same (see SP signals in the leftmost column), and these CP signals can be combined to estimate transmission line characteristics. Further, the CP signal (-1) of the 5th symbol from the beginning and the SP signal (+1) of the 4th symbol from the beginning of the 4th carrier from the right end (4th row in the 4th column from the right) are at predetermined intervals. The relationship is the same as that of SP signals adjacent in the diagonal direction, and the transmission line characteristics can be estimated by combining the CP signal and the SP signal. A similar diagonally adjacent relationship is established between all SP signals and CP signals on the fourth carrier from the right, and transmission line characteristics can be estimated from these.

As described above, in the present invention, the sign of the CP signal is determined so as to maintain the relationship (periodicity) of the sign inversion (that is, the multiplication coefficient) of the SP signal, and the CP signal can also be used as the SP signal. This corresponds to an increase in the SP signal, and the transmission line characteristics can be estimated more accurately than in the past. Further, conventionally, processing the SP signal and the CP signal separately complicates the processing, but in the present invention, the CP signal can be regarded as the SP signal and processed uniformly (for example, in the receiving device). Since the transmission line characteristic estimation processing performed between the SP signals can be expanded to the area of the CP signal and collectively processed), the efficiency of the processing can be improved.

Next, another example will be described for each OFDM frame generated by the OFDM frame components 14 and 15. FIG. 3 is an example of using an orthogonal pilot signal generated by the null method. The OFDM frame component 14 of the first transmission system uses, for example, the arrangement of the pilot carriers in FIG. 2 as it is, but configures the transmission frame with the pilot carriers at predetermined positions as null data (amplitude 0).

FIG. 3A shows an example of the arrangement of the data symbol of the 1 system and the pilot signal. The figure is an example of Dx = 3, Dy = 4. In the figure, the white squares indicate the data symbols, the diagonal hatched squares indicate the normal (coefficient +1 multiplied) pilot signal, and the black squares indicate the null data (coefficient multiplied by 0) pilot signal. There is.

In the OFDM frame of FIG. 3A, SP signals are arranged every 12 carriers in the carrier (frequency) direction and every 4 symbols in the symbol (time) direction. In the line shifted by 1 symbol in the symbol (time) direction, the SP signal is arranged with a Dx (3 carrier) shift in the carrier (frequency) direction from the previous line. A CP (Continual Pilot) signal is arranged at the carrier at the end (right end) of the OFDM frame.

In FIG. 3A, the symbol of the carrier at the beginning (first row) and the left end (first column) of the OFDM frame is normal (multiply by the coefficient + 1), and the symbol in the second row and the fourth column is null data (coefficient 0). (Multiply), the symbol in the 3rd row and 7th column is normal (multiply by the coefficient + 1), and the symbol in the 4th row and 10th column is null data (multiply by the coefficient 0). Then, with reference to the carrier-symbol space (4 rows and 12 columns) including the carriers at the beginning and left ends of this OFDM frame, the coefficient +1 (normal) and the coefficient 0 (null) are alternately alternated in the SP signal in the carrier direction and the symbol direction. Multiply by. As a result, as shown in FIG. 3A, normal (coefficient + 1 multiplied) SP signals and null data (coefficient 0 multiplied) SP signals are alternately arranged in the symbol direction, the carrier direction, and the diagonal direction. ..

Further, in the present invention, the pilot signal generated by the null method is also used for the CP signal. In FIG. 3A, for the CP signal arranged on the carrier at the end (right end) of the OFDM frame, the Dy symbols from the beginning of the OFDM frame are usually (multiplied by the coefficient + 1), and the next Dy symbols are used. The symbol is null data (a pilot signal multiplied by a coefficient of 0), and then the CP signal is alternately multiplied by a coefficient of +1 and a coefficient of 0 for each Dy symbol. As a result, as the CP signal, a normal (coefficient + 1) CP signal and a null data (coefficient 0) CP signal are repeated by Dy symbols.

In the arrangement of FIG. 3 (A), among the pilot signals of FIG. 2 (B), the sign-inverted (multiplied by the coefficient -1) pilot signal was replaced with the null data (multiplied by the coefficient 0) pilot signal. Equal to one.

The OFDM frame component 15 of the second transmission system uses the same pilot carrier arrangement as the OFDM frame of the first system, but has a normal (coefficient + 1 multiplied) pilot signal and null data (coefficient 0 multiplied) pilot signal. The coefficients (+1 and 0) are completely interchanged to form a transmission frame. FIG. 3B shows an example of the arrangement of the data symbols of the 2 system and the pilot signal. In the figure, the white squares indicate the data symbols, the diagonal hatched squares indicate the normal (coefficient +1 multiplied) pilot signal, and the black squares indicate the null data (coefficient multiplied by 0) pilot signal. There is.

In the OFDM frame of FIG. 3B, SP signals are arranged every 12 carriers in the carrier (frequency) direction and every 4 carriers in the symbol (time) direction, and are shifted by one symbol in the symbol (time) direction. In the row, the SP signal is arranged with a Dx (= 3) shift in the carrier (frequency) direction from the previous row. In FIG. 3B, the carrier symbol at the beginning (first row) and left end (first column) of the OFDM frame is set as null data (multiplied by the coefficient 0), and based on this, the symbol direction, the carrier direction, and further diagonally. In the direction, the SP signal of null data (multiplying the coefficient 0) and the normal SP signal (multiplying the coefficient +1) are arranged alternately.

Further, as the CP signal, the pilot signal generated by the null method is used. That is, in the second system, as shown in FIG. 3B, for the CP signal arranged on the carrier at the end (right end) of the OFDM frame, Dy symbols from the beginning of the OFDM frame are multiplied by null data (coefficient 0). (Pilot signal), the next Dy symbols are normal (multiply by coefficient +1), and then the CP signal is alternately multiplied by coefficient 0 and coefficient +1 for each Dy symbol. As a result, as the CP signal, the CP signal of null data (coefficient 0) and the normal CP signal (coefficient +1) are repeated by Dy symbols.

As a result, the pilot signal of FIG. 3 (B) has a multiplication coefficient for the normal (coefficient + 1 multiplied) pilot signal and the null data (coefficient 0 multiplied) pilot signal in the pilot signal of FIG. 3 (A). Equal to a complete replacement of (+1,0).

As described above, also in FIG. 3, in the CP signal, the arrangement of the normal CP signal and the null data is determined so as to maintain the relationship (periodicity) of the coefficient multiplication of +1 and 0 of the SP signal. This makes it possible to use the CP signal as an SP signal. In each of the 1st system and the 2nd system, the sign relationship between the CP signal and the adjacent SP signal (particularly, the diagonally adjacent sign relationship) is the same as the relationship between the other adjacent SP signals, and the 1st system and the 2nd system have the same sign relationship. The point that the SP signal (+1) and the null data (0) are opposite to each other in the system is also maintained in the CP signal. This makes it possible to estimate the transmission line characteristics by combining the CP signal and the SP signal.

In the present invention, even when the null method is adopted, the multiplication coefficient (+1,0) of the CP signal is determined so as to maintain the relationship (periodicity) of the multiplication coefficient of the SP signal, and the CP signal can also be used as the SP signal. Since it can be used, it corresponds to substantially increasing the SP signal, and the transmission line characteristics can be estimated more accurately than in the conventional case. Further, conventionally, if the SP signal and the CP signal are processed separately, the processing becomes complicated. However, in the present invention, the CP signal can be regarded as the SP signal and processed uniformly in the receiving device. It is possible to improve the efficiency of processing.

The OFDM frame structures of FIGS. 2 and 3 include SP signals distributed in predetermined symbol (time) intervals and carrier (frequency) intervals, and CP signals continuously arranged in predetermined frequency carriers. In the OFDM frame including and, at least one OFDM frame is obtained by alternately multiplying the SP signal by the first coefficient and the second coefficient in the symbol (time) direction and the carrier (frequency) direction, and CP. It can be said that the first coefficient and the second coefficient are alternately multiplied for each number corresponding to a predetermined symbol (time) interval with respect to the signal.

In the first embodiment described above, the configuration and operation of the transmission device 10 have been described, but the present invention is not limited to this, and the semiconductor chip mounted on the transmission device 10 includes the OFDM frame components 14, 15 and the pilot. It may be configured as a chip having the function of the signal generation unit 16. That is, an OFDM frame included in an SP signal mounted on a transmitter and distributed at predetermined symbol (time) intervals and carrier (frequency) intervals, and a CP signal continuously arranged at a predetermined frequency carrier. Corresponds to at least the SP signal obtained by alternately multiplying the first coefficient and the second coefficient in the symbol (time) direction and the carrier (frequency) direction, and the symbol (time) interval of the SP signal. It may be configured as a chip capable of creating an OFDM frame including a CP signal in which a first coefficient and a second coefficient are alternately multiplied for each number.

In this way, a chip of a transmission device that generates an OFDM signal including a CP signal whose code (multiplication coefficient) is determined so as to maintain the relationship (periodicity) of the code (multiplication coefficient) of the SP signal is configured. be able to.

Further, in a chip equipped with a plurality of transmission systems and mounted on a transmission device that transmits two types of OFDM signals, the first coefficient and the second coefficient are +1 and -1, and the coefficient multiplication is performed in one OFDM frame. And the coefficient multiplication may not be performed in the other OFDM frame. Further, the first coefficient and the second coefficient are +1 and 0, and in two types of OFDM frames, the coefficients to be multiplied by the SP signal or CP signal at the corresponding positions can be reversed.

Further, in the first embodiment described above, the configuration and operation of the transmission device 10 have been described, but the present invention is not limited to this, and may be configured as a transmission method for transmitting an OFDM signal by a plurality of transmission systems. That is, according to the data flow of FIG. 1, the step of performing error correction coding processing of the transmitted data, the step of mapping the error correction encoded data to the IQ plane by a predetermined modulation method, and the mapped data. Based on the process of performing spatiotemporal coding processing and dividing the spatiotemporal coded data into two systems and the spatiotemporal coded data of each system, it is distributed to predetermined symbol (time) intervals and carrier (frequency) intervals. A step of generating an OFDM frame including an SP signal arranged in a row and a CP signal continuously arranged in a predetermined frequency carrier, at least in the symbol (time) direction and the carrier (frequency) direction. The SP signal obtained by alternately multiplying the coefficient 1 and the second coefficient, and the CP obtained by alternately multiplying the first coefficient and the second coefficient for each number corresponding to the symbol (time) interval of the SP signal. Transmission in which an OFDM signal is transmitted by a plurality of transmission systems including a step of creating an OFDM frame including a signal and a step of performing inverse high-speed Fourier conversion of the generated OFDM frame signal to generate an OFDM signal in a time region. It may be configured as a method.

In this way, it is possible to configure a transmission method for transmitting an OFDM signal including a CP signal whose code (multiplication coefficient) is determined so as to maintain the relationship (periodicity) of the code (multiplication coefficient) of the SP signal. can.

According to the above-mentioned chip and transmission method, in the MIMO transmission method or the MISO transmission method, it is possible to generate an OFDM signal capable of more accurately estimating the transmission line characteristics without increasing the SP signal.

(Embodiment 2)
Next, the receiving device according to the second embodiment of the present invention will be described.

FIG. 4 is a block diagram showing an example of the configuration of the receiving device. The receiving device 20 is a receiving device capable of receiving a plurality of OFDM transmission signals, and has a receiving antenna Rx1, Rx2, an FFT (Fast Fourier Transform) unit 21 and 22, a transmission line characteristic estimation unit 23, and a spatiotemporal decoding unit 24. It includes a demapping unit 25 and an error correction decoding unit 26. Here, a MIMO transmission type receiving device having two receiving antennas and two FFT units will be described, but a MIMO transmission type receiving device having one receiving system can also be configured in the same manner.

When the receiving antennas Rx1 and Rx2 of the receiving device 20 receive the OFDM signal transmitted by the transmitting device 10 of FIG. 1, they perform frequency conversion, GI (guard interval) removal processing, and the like (not shown). The received signals are output to the FFT units 21 and 22, respectively. Here, the OFDM signal transmitted from at least one received transmission system alternately alternates between the first coefficient and the second coefficient (for example, +1 and -1) in the symbol (time) direction and the carrier (frequency) direction. It includes a multiplied SP signal and a CP signal that is alternately multiplied by a first coefficient and a second coefficient for each number corresponding to the symbol (time) interval of the SP signal.

The FFT units 21 and 22 receive the OFDM signal from which the GI has been removed as an input, perform a fast Fourier transform on the OFDM signal in the time domain, generate an OFDM signal in the frequency domain, and generate a transmission path characteristic estimation unit 23 and a spatiotemporal decoding unit. Output to 24.

The transmission line characteristic estimation unit 23 extracts a pilot signal (SP, CP) from the OFDM signal converted into the frequency domain input from the FFT units 21 and 22, respectively. The transmission line characteristics (transmission line response) of each pilot signal position are estimated based on the reception state (reception intensity, phase, etc.) of the extracted pilot signal, and then, other than the pilot signal position by an appropriate method such as interpolation processing. The transmission line characteristics at all symbol positions are estimated, and the estimated transmission line characteristics are output to the spatiotemporal decoding unit 24.

In the present invention, the received CP signal has a code (multiplication coefficient) determined so as to maintain the relationship (periodicity) of the code (multiplication coefficient) of the SP signal. Therefore, in estimating the transmission line characteristics, the code (multiplication coefficient) is determined. The CP signal is also used as the SP signal. That is, not only the combination of SP signals but also the combination of SP signals and CP signals is used to estimate the transmission line characteristics from a plurality of transmission systems. It is desirable that the CP signal is also regarded as an SP signal and processed uniformly.

The spatiotemporal decoding unit 24 is based on the transmission line characteristics input from the transmission line characteristic estimation unit 23 and the OFDM signal converted into the frequency region by the FFT units 21 and 22, based on the data carrier and transmission line characteristics of the OFDM signal. The spatiotemporal decoding process is performed, and the spatiotemporally decoded data carrier (symbol) is output to the demapping unit 25. As the spatiotemporal decoding process, a decoding process corresponding to STBC or the like is performed.

The demapping unit 25 takes the data carrier (symbol) spatiotemporally decoded from the spatiotemporal decoding unit 24 as an input, performs demapping (carrier demodulation) corresponding to the modulation method, and outputs the processing result to the error correction decoding unit 26. do. As the modulation method, QPSK, 16QAM, 64QAM, 256QAM, 1024QAM, 4096QAM and the like are used.

The error correction / decoding unit 26 receives the data demapped by the demapping unit 25 as an input, and performs an error correction / decoding process corresponding to the error correction coding process on the transmitting side. If necessary, processing such as deinterleaving and energy backdiffusion may be performed. The error correction / decoding processed data is output as the output data of the receiving device.

Although the receiving device of the second embodiment has been described as a receiving device of the MIMO transmission method, it may be a receiving device corresponding to the MISO transmission method having one system of a receiving antenna, an FFT unit, and a transmission line characteristic estimation unit. good.

In the second embodiment described above, the configuration and operation of the receiving device 20 have been described, but the present invention is not limited to this, and the semiconductor chip mounted on the receiving device 20 has the function of the transmission line characteristic estimation unit 23. It may be configured as a chip to have. That is, in the chip mounted on the receiving device, at least the SP signal obtained by alternately multiplying the first coefficient and the second coefficient in the symbol (time) direction and the carrier (frequency) direction, and the symbol of the SP signal ( The OFDM signal including the CP signal obtained by alternately multiplying the first coefficient and the second coefficient for each number corresponding to the time) interval is processed, and the SP signal and the CP signal are combined to transmit the plurality of transmissions. It may be configured as a chip capable of estimating the transmission line characteristics from the system. Further, in the chip mounted on the receiving device, the processing for estimating the transmission line characteristics may be uniformly processed by regarding the CP signal as the SP signal.

In this way, in the chip of the receiving device that receives the OFDM signal including the CP signal whose code (multiplication coefficient) is determined so as to maintain the relationship (periodicity) of the code (multiplication coefficient) of the SP signal, the CP The signal can also be used as an SP signal to form a chip that estimates transmission line characteristics.

Further, in the second embodiment described above, the configuration and operation of the receiving device 20 have been described, but the present invention is not limited to this, and the OFDM signals transmitted from a plurality of transmission systems are received to estimate the transmission line characteristics. It may be configured as a receiving method for performing the above. That is, in accordance with the data flow of FIG. 4, a step of receiving an OFDM signal transmitted from a plurality of transmission systems and a step of performing high-speed Fourier conversion of the received OFDM signal to generate an OFDM signal in the frequency region, which is a symbol. The SP signal obtained by alternately multiplying the first coefficient and the second coefficient in the (time) direction and the carrier (frequency) direction, and the first coefficient for each number corresponding to the symbol (time) interval of the SP signal. A step of generating an OFDM signal including a CP signal that is alternately multiplied by a second coefficient and a step of estimating transmission line characteristics from the plurality of transmission systems by combining the SP signal and the CP signal. A step of performing spatiotemporal decoding processing based on the estimated transmission line characteristics and the OFDM signal converted into the frequency region, and a step of demapping (carrier demodizing) the spatiotemporally decoded data symbol. It may be configured as a receiving method including a step of performing an error correction / decoding process on the mapped data. In the step of estimating the transmission line characteristics in the receiving method, the CP signal may be regarded as an SP signal and uniformly processed.

In this way, in the receiving method for receiving the OFDM signal including the CP signal whose code (multiplication coefficient) is determined so as to maintain the relationship (periodicity) of the code (multiplication coefficient) of the SP signal, the CP signal is used. It can also be used as an SP signal to configure a receiving method for estimating transmission line characteristics.

According to the receiving device, the chip, and the receiving method in the present invention, in the MIMO transmission method or the MISO transmission method, the transmission line characteristics can be estimated more accurately by using the CP signal as the SP signal as well.

Although the above embodiments have been described as typical examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and modifications can be made without departing from the scope of claims. For example, it is possible to combine the plurality of constituent blocks described in the embodiment into one, or to divide one constituent block into one.

10 Transmitter 11 Error correction coding unit 12 Mapping unit 13 Spatio-temporal coding unit 14 OFDM frame configuration unit 15 OFDM frame configuration unit 16 Pilot signal generation unit 17 IFFT unit 18 IFFT unit 20 Receiver 21 FFT unit 22 FFT unit 23 Transmission Road characteristic estimation unit 24 Space-time decoding unit 25 Demapping unit 26 Error correction decoding unit

Claims (7)

In a transmission device that has multiple transmission systems and transmits OFDM signals.
The first and second OFDM frames including SP signals distributed at predetermined symbol (time) intervals and carrier (frequency) intervals and CP signals continuously arranged at predetermined frequency carriers. Equipped with an OFDM frame component of
In at least one OFDM frame component, the SP signal is alternately multiplied by the first coefficient and the second coefficient in the symbol (time) direction and the carrier (frequency) direction, and the CP signal is , The OFDM frame in which the first coefficient and the second coefficient are alternately multiplied for each number corresponding to the same predetermined symbol (time) interval as the symbol (time) interval in which the SP signal is arranged is configured . ,
The OFDM frame composed of the at least one OFDM frame component is characterized in that the relationship (periodicity) between the first coefficient and the second coefficient in the SP signal is maintained in the CP signal as well. And the transmitter. In the transmitting device according to claim 1 , the first coefficient and the second coefficient are +1 and -1, and multiplication is performed in one OFDM frame component and not in the other OFDM frame component. A transmitter characterized by. In the transmitter according to claim 1 , the first coefficient and the second coefficient are +1 and 0, and the SP signal or CP signal at the corresponding position is multiplied in the first and second OFDM frame components. A transmitter characterized by opposite coefficients. Generates an OFDM frame including SP signals mounted on a transmitter and distributed at predetermined symbol (time) intervals and carrier (frequency) intervals, and CP signals continuously arranged at predetermined frequency carriers. It ’s a chip that
At least, the SP signal obtained by alternately multiplying the first coefficient and the second coefficient in the symbol (time) direction and the carrier (frequency) direction, and the number corresponding to the symbol (time) interval of the SP signal, the first. Includes a CP signal that is alternately multiplied by a factor of 1 and a factor of 2
A chip characterized by creating an OFDM frame in which the relationship (periodicity) between the first coefficient and the second coefficient in the SP signal is maintained in the CP signal . In a receiving device that receives OFDM signals transmitted from multiple transmission systems
The OFDM signals transmitted from at least one transmission system include an SP signal obtained by alternately multiplying a first coefficient and a second coefficient in the symbol (time) direction and the carrier (frequency) direction, and a symbol of the SP signal (the SP signal). A CP signal in which the first coefficient and the second coefficient are alternately multiplied for each number corresponding to the time interval is included, and the relationship (periodicity) between the first coefficient and the second coefficient in the SP signal is included. ) Is maintained in the CP signal as well .
A receiving device for estimating transmission line characteristics from the plurality of transmission systems by combining the SP signal and the CP signal. The receiving device according to claim 5 , wherein the processing for estimating the transmission line characteristics is uniformly processed by regarding the CP signal as an SP signal. It is a chip mounted on the receiving device.
At least, the SP signal obtained by alternately multiplying the first coefficient and the second coefficient in the symbol (time) direction and the carrier (frequency) direction, and the number corresponding to the symbol (time) interval of the SP signal, the first. A CP signal obtained by alternately multiplying a coefficient of 1 and a second coefficient is included, and the relationship (periodicity) between the first coefficient and the second coefficient in the SP signal is maintained in the CP signal as well. Process the OFDM signal that is
A chip characterized by estimating transmission line characteristics from a plurality of transmission systems by combining the SP signal and the CP signal.

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