JP6842844B2 - Transmitters, receivers, frame construction methods, chips, and programs - Google Patents

Description

The present invention relates to transmitters, receivers, frame construction methods, chips, and programs.

In recent years, attention has been focused on the LDPC code (low-density parity-check code), which is a high-performance error correction code, and has been introduced into various wireless systems. For example, the LDPC code is adopted in the wireless LAN standards IEEE 802.11ac, IEEE 802.11n, IEEE 802.11e, the advanced broadband satellite digital broadcasting system, DVB-T2, S2, and the like. .. The LDPC code is a kind of block code, and the longer the code length, the higher the correction ability. For example, in the advanced broadband satellite digital broadcasting system, DVB-T2, and DVB-S2, a code length of tens of thousands of bits is used.

On the other hand, in many wireless systems, an OFDM transmission method having excellent multipath resistance is often used. Patent Document 1 discloses a method for determining parameters of an OFDM transmission method (arrangement of pilot carriers, data carriers, etc.).
A wireless system that uses an LDPC code as the internal code of the OFDM transmission method has also been introduced. Of the standards listed above, IEEE802.11ac, IEEE802.11n, IEEE802.16e, and DVB-T2 fall under this category. Non-Patent Document 1 describes the DVB-T2 standard. Further, Patent Document 2, Patent Document 3, and Non-Patent Document 2 also describe a technique of using an LDPC code as an internal code of an OFDM transmission method.

In the OFDM transmission method, modulation symbols are assigned to a plurality of orthogonal carriers, so that modulation symbols corresponding to the number of carriers (K) can be transmitted in parallel per symbol. In addition to data carriers for transmitting information, carriers include pilot carriers for channel response estimation and TMCC (Transmission and Multiplexing) for transmitting transmission control signals for transmitting transmission parameters required for demodulation to the receiving side. There are Configuration and Control) carriers and AC (Auxiliary Channel) carriers for transmitting additional information. When the number of data carriers per symbol is D and the number of modulation multi-values of the data carriers is M1, the number of transmittable bits per symbol is D × log ₂ (M1). Further, in general, an OFDM frame (packet) in which a plurality of consecutive symbols are grouped together is used as a unit of modulation / demodulation. When the number of symbols constituting one OFDM frame is L, the number of transmittable bits per OFDM frame is L × D × log ₂ (M1).

The LDPC code is a block code. When the code length of the LDPC code is N _ldpc [bit], the coding process and the decoding process are performed with the block of _{N ldpc} [bit] including the information to be transmitted and the parity as one unit. This unit is called an LDPC block. That is, in the decoding process, _{decoding cannot be performed unless all the N ldpc} [bits] in the LDPC block are aligned. Therefore, the first bit of the LDPC block is detected, data for the subsequent N _ldpc [bits] is obtained, and then decoding is performed. It is necessary to process. Therefore, it is desirable that the number of transmittable bits by one OFDM frame is N _ldpc [bits] or more, and it is necessary that the first bit of the LDPC block can always be detected on the receiving side.

Japanese Patent No. 3691357 Japanese Unexamined Patent Publication No. 2013-214937 Japanese Patent No. 5524421

ETSI, “Digital Video Broadcasting (DVB); Frame structure channel coding and modulation for a second generation digital terrestrial television broadcasting system (DVB-T2)”, ETSI EN 302 755, V1.4.1, 2015 Hiroaki Miyasaka et al., "Examination of Pointers for Error Correction Codes in Next Generation Terrestrial Broadcasting", Technical Report of the Institute of Image Information and Television Engineers, vol.39, no.38, BCT2015-69, 2015, p.1-4

However, each of the above-mentioned prior arts has the following problems.
In the carrier arrangement method of the OFDM transmission method described in Patent Document 1, there is no description in particular considering the case where the LDPC code is used as the internal code.
Although Patent Document 2 describes the application of the LDPC code in the OFDM transmission method, it does not disclose a method for detecting the first bit of the LDPC block.
Patent Document 3 and Non-Patent Document 1 describe a method of transmitting and receiving an LDPC block in an OFDM transmission method, and describe a mechanism that enables normal decoding of the LDPC block. That is, a mechanism for detecting the first bit of the LDPC block is described. However, in the techniques described in Patent Document 3 and Non-Patent Document 1, when trying to store an LDPC block in an OFDM frame, there is a possibility that an unused region may occur in the OFDM frame. That is, the techniques described in Patent Document 3 and Non-Patent Document 1 may deteriorate the transmission efficiency.

Non-Patent Document 2 describes a technique for arranging LDPC blocks across a plurality of OFDM frames so that an unused region is not generated in the OFDM frame. In this case, since it is necessary to detect the head of the LDPC block in the OFDM frame, a control signal indicating the position of the head bit of the LDPC block is embedded. Although the technique of Non-Patent Document 2 improves the transmission efficiency as compared with the techniques of Patent Document 3 and Non-Patent Document 1, the number of bits for information transmission is slightly reduced by the control signal indicating the first bit position of the LDPC block. The problem remains. Further, since it is necessary for the transmitting side to embed a control signal indicating the position of the first bit of the LDPC block and for the receiving side to detect the control signal, there is also a problem that the transmitting circuit and the receiving circuit are complicated, respectively. ..

The present invention has been made based on the above-mentioned problem recognition. INDUSTRIAL APPLICABILITY According to the present invention, a transmitter, a receiver, a frame configuration method, a chip, for performing OFDM transmission using an LDPC code as an internal code without lowering transmission efficiency and without complicating a transmission / reception circuit. And provides a program.

[1] In order to solve the above problems, the transmission device according to one aspect of the present invention is a transmission device that uses a plurality of carriers orthogonal to each other and transmits an OFDM frame composed of a predetermined number of symbols. The LDPC encoder that encodes the data to be output with the LDPC and outputs the LDPC block, the data cell for transmitting the LDPC block output from the LDPC encoder in the OFDM frame, and the pilot signal as the demodulation reference are transmitted. A pilot cell for this purpose and a TMCC cell containing at least the OFDM frame synchronization information are arranged, and exactly n (n is an integer of 1 or more) LDPCs in the data cell included in one OFDM frame. It is characterized by including an OFDM frame generation unit for accommodating blocks.

[2] Further, in one aspect of the present invention, in the above-mentioned transmitting device, the OFDM frame is composed of (K × L) cells having K in the frequency direction and L in the number of symbols in the time direction. The OFDM frame generation unit sets the effective symbol length of the symbol as Te, the guard interval length as Tg, and the guard interval ratio R, which is the ratio of the guard interval length and the effective symbol length, as Tg / Te, and sets the guard. When the maximum integer equal to or less than the inverse number 1 / R of the interval ratio R is M and the integer less than or equal to M is Q, each of the symbols is based on the values of K and Q such that (K-1) is divisible by Q. , The pilot cells are arranged at regular intervals for each Q from the carrier at the end of the K carriers, and the pilot cells are continuously arranged on a constant carrier regardless of the symbol, and the data cell for each symbol is arranged. When the number is D and the code length of the LDPC block is N _ldpc bit, the condition of D × L = n × N _ldpc is satisfied, and the L TMCC cells are set to the same carrier in the OFDM frame. It is characterized by arranging.

[3] Further, in one aspect of the present invention, in the above transmission device, the OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number of symbols L in the time direction. When the number of modulation multi-values of the data cell is limited to m (m is an integer of 1 or more) of M1_1, M1-2, ..., M1_m, the OFDM frame generator is used for log ₂ ( The maximum pledge of M1_1), log ₂ (M1_2), ..., Log ₂ (M1_m) is N _bits , the effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval length and effective symbol. When the guard interval ratio R, which is the ratio of lengths, is Tg / Te, the maximum integer of the inverse number 1 / R or less of the guard interval ratio R is M, and the integer of M or less is Q, (K-1) is Q. Based on the values of K and Q that are divisible by, in each of the symbols, the pilot cells are arranged at regular intervals for each Q from the carrier at the end of the K carriers, and a constant carrier regardless of the symbol. When the pilot cells are continuously arranged in, the number of data cells for each symbol is D, and the code length of the LDPC block is N _ldpc bit, the condition is _{N bits} × D × L = n × N _ldpc. , And the L TMCC cells are arranged on the same carrier in the OFDM frame.

[4] Further, in one aspect of the present invention, in the above-mentioned transmitter, the OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number of symbols L in the time direction. The OFDM frame generation unit sets the effective symbol length of the symbol as Te, the guard interval length as Tg, and the guard interval ratio R, which is the ratio of the guard interval length and the effective symbol length, as Tg / Te, and sets the guard. When the maximum integer of the inverse number 1 / R or less of the interval ratio R is M and the integer of M or less is Q, it is based on the values of K and Q such that (K-1) is divisible by Q, and L is Nsp. Based on the values of L and Nsp that are divisible by (Nsp is an integer of 2 or more), the pilot cells are arranged in both the frequency direction and the time direction so that the pilot cells are arranged in a two-dimensional array of L rows and K columns. In each of the symbols, the pilot cells are arranged at intervals of Q lines in the frequency direction, and in the carrier in which the pilot cells can be arranged, the pilot cells are arranged at intervals of Nsp symbols in the time direction. When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit, the condition of D × L = n × N _ldpc is satisfied, and the L TMCC cells are converted into the OFDM. It is characterized in that it is arranged on the same carrier in the frame.

[5] Further, in one aspect of the present invention, in the above-mentioned transmitter, the OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number of symbols L in the time direction. The OFDM frame generation unit uses the consecutive Fs (Fs is a positive integer) OFDM frames as superframes, the effective symbol length of the symbol as Te, the guard interval length as Tg, and the guard interval length. When the guard interval ratio R, which is the ratio between and the effective symbol length, is Tg / Te, the maximum integer equal to or less than the inverse of the guard interval ratio R is M, and the integer less than M is Q, then (K-1). ) Is divisible by Q, and the pilot cells are arranged in both the frequency direction and the time direction so that the pilot cells are arranged in both the frequency direction and the time direction. ) In a two-dimensional array of rows and K columns, the pilot cells are arranged at intervals of Q lines in the frequency direction in each of the symbols, and Nsp (Nsp) in the time direction in the carrier in which the pilot cells can be arranged. Places the pilot cells at intervals of (2 or more integers) symbols, and maintains the arrangement intervals of the pilot cells for each Nsp symbol even at a location straddling the boundary of the OFDM frame. Fs × L) is a multiple of Nsp, and when the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit, the condition of D × L = n × N _{ldpc is satisfied.} , L of the TMCC cells are arranged on the same carrier in the OFDM frame, and a signal for detecting the OFDM frame at the head of the super frame is sent to the TMCC at a predetermined symbol in the head OFDM frame. It is characterized in that it is arranged in a cell.

[6] Further, one aspect of the present invention is the transmission device for transmitting the OFDM frame by the spatial multiplexing method MIMO of the spatial multiplexing number Nant (Nant is an integer of 2 or more) in the above-mentioned transmitting device. The OFDM frame generator divides the LDPC block into Nant sub-blocks, and the OFDM frame corresponding to each transmitting antenna so that each of the divided sub-blocks corresponds to Nant transmitting antennas. The feature is that exactly an integer number of the sub-blocks are accommodated in a data cell in the OFDM frame, and each OFDM frame generated by the OFDM frame generator is transmitted from the respective transmitting antenna. To do.

[7] Further, in one aspect of the present invention, in the transmission device, the OFDM frame generation unit modulates the LDPC block output from the LDPC encoder and stores the data signal in the data cell. Each of the modulation unit to be output, the pilot signal generation unit to generate the pilot signal, the TMCC signal generation unit to generate the TMCC signal including at least the OFDM frame synchronization information, and the symbols arranged in the OFDM frame in the time direction. In addition, a frame configuration pattern storage unit that stores arrangement information representing carriers for arranging the data cell, the pilot cell, and the TMCC cell, the data signal output from the modulation unit, and the pilot signal generation unit. A switch that inputs the pilot signal output from the above and the TMCC signal output from the TMCC signal generator, switches the data signal, the pilot signal, and the TMCC signal according to a control signal, and outputs the data signal. , The arrangement information is read out for each symbol from the frame configuration pattern storage unit, the data signal is arranged in the data cell, the pilot signal is arranged in the pilot cell, and the TMCC signal is arranged in the TMCC cell. It is characterized by including a switch control unit that supplies the control signal to the switch.

[8] Further, the receiving device according to one aspect of the present invention is a receiving device that uses a plurality of carriers orthogonal to each other and receives an OFDM frame composed of a predetermined number of symbols, and is arranged in the OFDM frame. The TMCC signal reception processing unit that detects the synchronization of the OFDM frame by acquiring the TMCC signal from the TMCC cell and acquires the transmission parameter, and the data cell included in the OFDM frame based on the transmission parameter. With respect to the demodulator that acquires exactly n LDPC blocks (n is an integer of 1 or more) per OFDM frame from the data cell while demodulating, and the LDPC block acquired by the demodulator. It is characterized by including an LDPC decoder that performs LDPC decoding processing and acquires data before LDPC encoding.

[9] Further, in one aspect of the present invention, in the above-mentioned receiving device, the OFDM frame to be received is composed of (K × L) cells having K in the frequency direction and L in the number of symbols in the time direction. Based on the values of K and Q such that (K-1) is divisible by Q, in each of the symbols, the pilot cells are set at regular intervals for each Q from the carrier at the end of the K carriers. When the pilot cells are continuously arranged on a constant carrier regardless of the symbol, the number of data cells for each symbol is D, and the code length of the LDPC block is _Nldpc bit. It is characterized in that the condition of D × L = n × N _{ldpc is satisfied.}

[10] Further, in one aspect of the present invention, in the above-mentioned receiving device, the OFDM frame to be received is composed of (K × L) cells having a number of carriers K in the frequency direction and a number of symbols L in the time direction. The number of modulation multi-values of the data cell is limited to m (m is an integer of 1 or more) of M1-1, M1-2, ..., M1_m, and log ₂ (M1-1), log ₂ (M1-2). ), ..., The greatest common divisor of _{log 2 (M1_m) is N bits,} and based on the values of K and Q such that (K-1) is divisible by Q, in each of the symbols, the K carriers. Pilot cells are arranged at regular intervals for each Q from the carrier at the end of, and the pilot cells are continuously arranged on a constant carrier regardless of the symbol, and the number of data cells for each symbol is D. When the code length of the LDPC block is N _ldpc bit, the condition of _{N bits} × D × L = n × N _{ldpc is satisfied.}

[11] Further, in one aspect of the present invention, in the above-mentioned receiving device, the OFDM frame to be received is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction. Based on the values of K and Q such that (K-1) is divisible by Q, and based on the values of L and Nsp such that L is divisible by Nsp (Nsp is an integer of 2 or more). Pilot cells are arranged in both the frequency direction and the time direction, and in the two-dimensional arrangement of L rows and K columns, the pilot cells are arranged at intervals of Q lines in the frequency direction for each of the symbols. In the carrier where the pilot cell can be arranged, the pilot cell is arranged at intervals of Nsp symbols in the time direction, the number of data cells for each symbol is D, and the code length of the LDPC block is _Nldpc bit. When, the condition of D × L = n × N _{ldpc is satisfied.}

[12] Further, in one aspect of the present invention, in the above receiving device, the OFDM frames of consecutive Fs (Fs are positive integers) are superframes, and the TMCC signal receiving processing unit is the TMCC signal. The synchronization of the superframe is detected based on the above, and the received OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number of symbols L in the time direction. Yes, based on the values of K and Q such that (K-1) is divisible by Q, pilot cells are arranged so as to be dispersed in both the frequency direction and the time direction, and the superframe composed of Fs of the OFDM frames. In a two-dimensional array of (L × Fs) rows and K columns, the pilot cells are arranged at intervals of Q lines in the frequency direction in each of the symbols, and the pilot cells can be arranged in the time direction in the carrier. The pilot cells are arranged at intervals of Nsp symbols (Nsp is an integer of 2 or more), and the pilot cells are arranged at intervals of Nsp symbols even at a location straddling the boundary of the OFDM frame. It is maintained, (Fs × L) is a multiple of Nsp, and when the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit, D × L = n × N _ldpc. The feature is that the condition is satisfied.

[13] Further, one aspect of the present invention is a receiving device that receives the OFDM frame transmitted by a spatial multiplexing MIMO of a spatial multiplexing number Nant (Nant is an integer of 2 or more) in the above receiving device. Therefore, the demodulation unit acquires subblocks from each data cell of the Nant number of the OFDM frames corresponding to the spatial multiplexing, and the LDPC decoder is restored from the Nant number of the subblocks. The LDPC block is characterized in that LDPC decoding processing is performed.

[14] Further, one aspect of the present invention is a frame configuration method for constructing an OFDM frame for transmitting an OFDM frame using an LDPC code as an internal code, and an LDPC-encoded LDPC block in the OFDM frame. A data cell for transmitting the above, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least the OFDM frame synchronization information are arranged, and the above-mentioned is included in one of the OFDM frames. This is a frame configuration method characterized in that exactly n (n is an integer of 1 or more) of the LDPC blocks are accommodated in a data cell.

[15] Further, one aspect of the present invention is for transmitting an LDPC encoder that encodes data to be transmitted by an LDPC and outputs an LDPC block, and the LDPC block output from the LDPC encoder in an OFDM frame. A data cell, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information are arranged, and exactly n in the data cell included in one OFDM frame. The chip is characterized by comprising an OFDM frame generation unit for accommodating the LDPC blocks (n is an integer of 1 or more).

[16] Further, one aspect of the present invention is a TMCC signal reception processing unit that detects synchronization of the OFDM frame and acquires transmission parameters by acquiring a TMCC signal from a TMCC cell arranged in an OFDM frame. Then, based on the transmission parameter, the data cells included in the OFDM frame are demolished, and from the data cells, exactly n LDPC blocks (n is an integer of 1 or more) are accommodated per the OFDM frame. The chip is characterized by comprising a demodulator for each acquisition and an LDPC decoder for performing LDPC decoding processing on the LDPC block acquired by the demodulator to acquire data before LDPC coding.

[17] Further, one aspect of the present invention is an LDPC encoder that encodes data to be transmitted by an LDPC and outputs an LDPC block, and transmits the LDPC block output from the LDPC encoder in an OFDM frame. Data cell for transmitting, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information are arranged in the data cell included in one OFDM frame. This is a program for functioning as an OFDM frame generator that accommodates exactly n (n is an integer of 1 or more) LDPC blocks.

[18] Further, in one aspect of the present invention, a computer acquires a TMCC signal from a TMCC cell arranged in an OFDM frame to detect synchronization of the OFDM frame and acquire a transmission parameter. Based on the reception processing unit and the transmission parameters, the data cells included in the OFDM frame are demolished, and exactly n LDPCs (n is an integer of 1 or more) are accommodated from the data cells per OFDM frame. This is a program for functioning as a demodulator that acquires each block and an LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulator and acquires data before LDPC coding.

According to the present invention, it is not necessary to perform unnecessary padding processing or complicated processing for frame synchronization, and all transmittable bits (data cells in a frame) can be assigned to information transmission. That is, according to the present invention, the transmission efficiency can be improved without complicating the apparatus.

It is a block diagram which shows the schematic functional structure of the transmission device by embodiment of this invention. It is a schematic diagram which shows the arrangement example of the OFDM frame when the continuous pilot system is applied in the same embodiment. It is a schematic diagram which shows the arrangement example of the OFDM frame when the scatterd pilot system is applied in the same embodiment. It is a block diagram which shows the schematic functional structure of the receiving device by the same embodiment. In the same embodiment, it is a schematic diagram which shows the relationship between the LDPC block and the OFDM frame when the LDPC block is transmitted by OFDM using the MIMO method. It is a schematic diagram which shows the structure of the OFDM frame when the MIMO method is used in the same embodiment.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic functional configuration of a transmission device according to the present embodiment. As shown in the figure, the transmission device 1 includes a data acquisition unit 11, an LDPC encoder 12, a modulation unit 13, a pilot signal generation unit 16, a TMCC signal generation unit 17, a switch 21, and an OFDM frame timing control unit 31. The OFDM frame configuration pattern storage unit 33, the switch control unit 35, the IFFT unit 41, the quadrature modulation unit 42, the DA conversion unit 43, and the transmission high frequency unit 44 are included. The transmission device 1 having this configuration includes the data encoded by the LDPC in the OFDM frame and transmits the data. The OFDM frame uses a plurality of carriers orthogonal to each other and is composed of a predetermined number of symbols.
In addition, OFDM represents "Orthogonal Frequency Division Multiplexing", LDPC represents "low-density parity-check code", and TMCC represents "low-density parity-check code". It stands for "Transmission and Multiplexing Configuration and Control". Also, IFFT stands for "Inverse Fast Fourier Transform".

The data acquisition unit 11 acquires digital data to be transmitted from the outside and supplies it to the LDPC encoder 12.
The LDPC encoder 12 encodes the data supplied from the data acquisition unit 11 with the LDPC and sequentially outputs the data as an LDPC block. Specifically, the LDPC encoder 12 performs redundant coding for error correction. As will be described later, one OFDM frame accommodates exactly an integer number of LDPC blocks. The LDPC encoder 12 outputs the first bit of the first LDPC block in a certain OFDM frame according to the OFDM frame start timing signal supplied from the OFDM frame timing control unit 31.

The modulation unit 13 sequentially modulates the bits constituting the LDPC block output from the LDPC encoder 12 by a predetermined modulation method. The modulation unit 13 outputs a data signal to be stored in the data cell in the OFDM frame. The modulation method in the modulation unit 13 will be described later. The modulation unit 13 properly uses a plurality of types of modulation methods as needed. Further, for example, a plurality of types of modulation methods may be adaptively switched and used according to a radio wave propagation situation or the like. The modulation unit 13 performs symbol mapping according to the number of modulation multi-values for the bit strings input in series. It can also be considered that the modulation unit 13 performs serial / parallel conversion.

The pilot signal generation unit 16 generates a pilot signal according to the OFDM frame format under the control of the OFDM frame timing control unit 31. The pilot signal is a known reference signal used for channel estimation on the receiving side.
The TMCC signal generation unit 17 generates a TMCC signal according to the OFDM frame format under the control of the OFDM frame timing control unit 31.

The switch 21 inputs a data carrier (data cell) from the modulation unit 13, a pilot carrier (pilot cell) from the pilot signal generation unit 16, and a TMCC carrier (TMCC cell) from the TMCC signal generation unit 17. Then, the switch 21 switches the input signal according to the control signal from the switch control unit 35. The switch 21 outputs an OFDM frame composed of appropriately arranged signals as a result of this switching to the IFFT unit 41. That is, the switch 21 inputs the data signal output from the modulation unit 13, the pilot signal output from the pilot signal generation unit 16, and the TMCC signal output from the TMCC signal generation unit 17. Then, the switch 21 switches and outputs the data signal, the pilot signal, and the TMCC signal according to the control signal from the switch control unit 35. A buffer memory for temporarily storing a signal for one symbol, which is an OFDM frame or a part thereof, may be provided after the switch 21. Further, as will be described later, the switch control unit 35 controls switching of the switch 21 so as to have a predetermined frame configuration by referring to the OFDM frame configuration pattern storage unit 33.

The OFDM frame timing control unit 31 determines the start timing of the OFDM frame and generates a signal representing the start timing. The OFDM frame timing control unit 31 supplies a signal representing the start timing of the OFDM frame to the LDPC encoder 12, the pilot signal generation unit 16, the TMCC signal generation unit 17, and the switch control unit 35. Based on the timing signal supplied by the OFDM frame timing control unit 31, each of these units generates an OFDM frame. That is, the OFDM frame is generated and transmitted while the entire transmission device 1 is synchronized according to the timing signal output by the OFDM frame timing control unit 31.

The OFDM frame configuration pattern storage unit 33 stores information on the format of the OFDM frame to be transmitted. Specifically, the OFDM frame configuration pattern storage unit 33 stores the arrangement of carriers (cells) for each symbol in the OFDM frame. As will be described later, there are types of carriers such as data carriers, pilot carriers, and TMCC carriers. The OFDM frame configuration pattern storage unit 33 also stores information indicating how a plurality of LDPC blocks are arranged in the OFDM frame with respect to the data carrier (data cell). A specific example of the configuration of the OFDM frame will be described later with reference to FIGS. 2, 3 and 6.

The switch control unit 35 reads the start timing of the OFDM frame from the signal from the OFDM frame timing control unit 31. Then, the switch control unit 35 reads out the carrier arrangement in each symbol from the OFDM frame configuration pattern storage unit 33 in order from the first symbol of the OFDM frame. Then, the switch control unit 35 controls to switch the switch 21 according to the read carrier arrangement information. That is, the switch control unit 35 supplies the control signal to the switch 21 so that the data signal is arranged in the data cell, the pilot signal is arranged in the pilot cell, and the TMCC signal is arranged in the TMCC cell. By this control of the switch control unit 35, the switch 21 operates so as to switch each signal and output to the IFFT unit 41 according to a predetermined frame configuration.

The IFFT unit 41 converts the frequency domain signal input from the switch 21 into a time domain signal. Specifically, the IFFT unit performs an inverse fast Fourier transform process.
The quadrature modulation unit 42 modulates the complex signal input from the IFFT unit 41 as an in-phase component of the carrier wave and a quadrature component.
The DA conversion unit 43 converts the modulation signal input from the quadrature modulation unit 42 into digital-to-analog.
The transmission high frequency unit 44 converts the modulated signal output from the DA conversion unit 43 into a radio frequency and transmits it.

Of the above units, at least a function including a switch 21, an OFDM frame timing control unit 31, an OFDM frame configuration pattern storage unit 33, and a switch control unit 35 constitutes an OFDM frame generation unit. As a function of the OFDM frame generation unit, a modulation unit 13, a pilot signal generation unit 16, and a TMCC signal generation unit 17 may be added.
The OFDM frame generator includes a data cell for the LDPC block output from the LDPC encoder 12 in the OFDM frame, a pilot cell for the pilot signal as a demodulation reference, and a TMCC cell containing at least the OFDM frame synchronization information. To place. As a result, the OFDM frame generator constitutes an OFDM frame and outputs it. At that time, the OFDM frame generation unit accommodates exactly n LDPC blocks (n is an integer of 1 or more) in the data cell included in one OFDM frame.

With the above configuration, the transmission device 1 configures the OFDM frame using appropriately determined parameters so that the transmission efficiency is improved when the LDPC is used as the internal code of the OFDM frame.
Here, the parameters are premised on the number of FFT points, the number of carriers constituting the OFDM frame (K), the pilot insertion interval (Q) indicating how many carriers the pilot signal is inserted for, and the pilot insertion interval. The number of pilot carriers, the number of data carriers (D) indicating how many data carriers are used to transmit data among the K carriers, and the length in the time direction (number of symbols) constituting the OFDM frame. ), The number of LDPC blocks stored in one OFDM frame (n), the number of pilot carriers among K carriers and carriers other than data carriers (TMCC, AC, etc.), etc. It is a numerical value such as.
The "AC" will be described later.

Here, first, five possible cases will be described. Examples of parameters will be described later for each of these cases.

[Case 1] In this case, a continuous pilot system (continuous pilot system) is used as the arrangement of the pilot signals. In the continuous pilot system, the carrier allocated for the pilot signal does not change over time and is constant. In addition, the data modulation method is arbitrary. That is, the OFDM frame is configured so that the transmission efficiency is improved for an arbitrary number of modulation values.
[Case 2] In this case, the continuous pilot method is used as the arrangement of the pilot signals. In addition, restrictions are set on the data modulation method. That is, on the premise of a predetermined set of modulation multi-values, the OFDM frame is configured so that the transmission efficiency is improved for any modulation multi-values belonging to the set. By adding restrictions to the number of modulation multi-values, the method of configuring the OFDM frame becomes diverse.
[Case 3] In this case, a scatterd pilot method (distributed pilot method) is used as the arrangement of pilot signals. In the scattered pilot scheme, the carriers allocated for the pilot signal change over time within the OFDM frame. When a carrier is used as a pilot carrier, the period (period in the time direction) in which the carrier is used as a pilot carrier is defined as Nsp (number of symbols). Then, the frame length (the number of symbols in one frame) L is set to an integral multiple of Nsp.
[Case 4] In this case, a scatterd pilot system is used as the arrangement of the pilot signals. Further, when the period in which a certain carrier is used as a pilot carrier is Nsp, consecutive Nsp OFDM frames are treated as one super frame. As a result, even when the frame length L is not a period of Nsp, the arrangement of carriers used as pilot carriers in the head symbol of the super frame is always constant. Once the symbol position in the super frame is determined, the placement of the pilot carrier is determined.
[Case 5] In this case, MIMO, which is a spatial multiplexing method, is used. On the transmitting device side, the number of transmitting antennas is Nant. That is, the spatial multiple number is Nant. The LDPC block output from the LDPC encoder is divided into Nant sub-blocks and transmitted from each transmitting antenna. On the receiving side, Nant sub-blocks are restored, and the LDPC block is reproduced based on those sub-blocks.

First, the method of configuring the OFDM frame in "Case 1" and "Case 2" described above, that is, when the continuous pilot method is used, will be described.
FIG. 2 is a schematic view showing an example of arrangement of OFDM frames when the continuous pilot method is applied in the present embodiment. In the figure, the horizontal axis is frequency and the vertical axis is time. As shown, one OFDM frame contains K carriers (which may be referred to as "subcarriers"). Each carrier is given a carrier number. The carrier numbers are written as 0, 1, 2, ..., K-1. Further, one OFDM frame includes L symbols (transmission symbols, units in the time direction). Each symbol is given a symbol number. The symbol numbers are written as 0, 1, 2, ..., L-1. The single circle (white circle, black circle, double circle) shown is a cell (also referred to as a "carrier" or the like). That is, one OFDM frame is composed of (L × K) cells arranged in two-dimensional L rows and K columns.

There are three types of cells. The cells indicated by white circles are data cells and have LDPC-encoded data to be transmitted. The cells indicated by black circles are pilot cells, and both the transmitting side and the receiving side have known pilot signals. The pilot signal is used as a reference during demodulation. The cells indicated by double circles are TMCC cells, and have information for detecting the synchronization of OFDM frames and information on transmission parameters. In the illustrated OFDM frame, which type of cell (data cell, pilot cell, TMCC cell) is arranged is determined by the frequency (carrier).
In addition to the above three types of cells, an AC (Auxiliary Channel) cell for transmitting auxiliary additional information may be further arranged.

Each carrier is modulated by a modulation scheme such as QPSK (Quaternary Phase-Shift Keying), 16QAM (16 Quadrature Amplitude Modulation), 64QAM, 256QAM, or the like.

One OFDM frame is divided into a plurality of LDPC blocks. The OFDM frame delimiter is also the LDPC block delimiter. That is, the timing at which the OFDM frame is delimited is the timing that serves as the reference for the transmission of the LDPC block. In the illustrated example, one OFDM frame contains n LDPC blocks. Numbers 1, 2, ..., N are assigned to each LDPC block.

Here, the relationship between the number of carriers and the placement interval of pilot carriers will be described.
Let Te be the effective symbol length of the transmission symbol, Tg be the guard interval length, and R be Tg / Te, which is the ratio of the guard interval length to the effective symbol length. R is called the guard interval ratio. Then, let M be the maximum integer less than or equal to the reciprocal of the guard interval ratio (1 / R), and let Q be any integer less than or equal to M. Q is the placement interval of the pilot carrier. If the value of the number of carriers K is (multiple of Q + 1), pilot carriers that serve as a reference for demodulation can be arranged at regular intervals for each Q from the carriers at both ends. In the illustrated example, the pilot carriers are arranged at regular intervals of exactly Q lines from the carriers at both ends. In this case, assuming that p is a non-negative integer, the carrier number k for transmitting the pilot carrier is determined by k = p × Q. However, 0 ≦ k ≦ K-1. In the illustrated OFDM frame, Q = 8 is set as an example. Therefore, from the carrier on the left end of the figure, carrier numbers k = 0, 8, 16, ..., And every eight pilot carriers are arranged. Further, since the carrier number K is (multiple of 8 + 1), the carrier number K-1 at the right end of the figure is a multiple of 8. Therefore, the pilot carrier is also arranged on the rightmost carrier.
As described above, by setting the value of the number of carriers K to (multiple of Q + 1), the pilot carriers can be arranged at both ends of the carriers and between them every Q lines.

Next, the relationship between the pilot carrier placement interval Q and the guard interval ratio R will be described.
As an example, consider the case where the guard interval ratio R = 1/8. Since the maximum integer equal to or less than the reciprocal of the guard interval ratio (1 / R) is M, M = 8. That is, the maximum interval between pilot carriers is 8. Then, an arbitrary integer Q equal to or less than M can be introduced, and Q can be used as the pilot carrier interval. Therefore, the pilot carrier spacing can be any integer less than or equal to 8. However, if the value of Q is made too small, the ratio of pilot carriers to all carriers will increase, and the data transmission efficiency will decrease.

An LDPC block encoded by an LDPC code, which is an internal code, is assigned to a data carrier (data cell) indicated by a white circle. When the modulation multi-value number of one data cell is M1, Ns [bits] can be assigned to the data cell. However, Ns = log ₂ (M1). _Assuming that the code length of the LDPC code (LDPC block length, block length) is N ldpc [bit], the number of data cells required to transmit one LDPC block is (N _ldpc / Ns). is there.
As an example, when the carrier modulation method is 64QAM, the modulation multi-value number M1 is 64, so Ns = log ₂ (64) = 6 [bits]. Therefore, when N _ldpc = 64800 [bits], the number of data cells required to transmit one LDPC block is 10800 (= 64800/6).

The transmission device 1 accommodates an LDPC block composed of _{(N ldpc} / Ns) data cells, each of which has Ns [bit] information, in an OFDM frame. As described above, the OFDM frame is composed of L symbols. The transmission device 1 accommodates exactly an integer number of LDPC blocks in one OFDM frame. As a result, all the data cells in the OFDM frame are used without waste, and the transmission efficiency is improved.
In the conventional technique, there may be a case where an integer number of LDPC blocks cannot be contained in exactly one OFDM frame. In that case, since the surplus data cell is not used for data transmission, it is wasted and the transmission efficiency is deteriorated. On the other hand, in the transmission device 1 of the present embodiment, the data cell can be used for data transmission without waste.

The transmission device 1 configures the OFDM frame so as to satisfy the condition represented by the following equation (1) so that one OFDM frame accommodates exactly an integer number of LDPC blocks.

D × L × Ns = n × N _ldpc・ ・ ・ (1)

In the equation (1), D is a positive integer and is the number of data carriers constituting one OFDM frame. Further, as described above, L is the OFDM frame length, that is, the number of transmission symbols constituting one OFDM. Further, n is a positive integer.
The transmission device 1 constructs an OFDM frame using the values of D and L so as to satisfy the above equation (1). As a result, n LDPC blocks are accommodated in one OFDM frame.

Parameters in [Case 1]:
In some cases, such as when adaptive modulation is used, the modulation method can be switched, that is, the number of modulation multi-values can be switched. When it is possible to switch to an arbitrary modulation method, that is, when it is possible to switch to an arbitrary number of modulation multi-values, Ns in the equation (1) may be set to 1. When Ns = 1, the equation (1) is expressed as the following equation (2).

D × L = n × N _ldpc・ ・ ・ (2)

By using D and L that satisfy the condition of the above equation (2), the transmission device 1 can maintain high transmission efficiency even when switching to an arbitrary number of modulation values.

Table 1, Table 2, Table 3, Table 4, and Table 5 are examples of parameters that can be used in "Case 1" and when the number of FFT points is 2048 or 8192. Further, an example of these parameters is the case where the LDPC block length N _ldpc = 64800 [bit] or N _ldpc = 44880 [bit]. The transmitter 1 constructs and transmits an OFDM frame using, for example, any of the parameters listed in these tables.
Table 1 shows an example in which the LDPC block length N _ldpc = 64800 [bit], the number of FFT points is 2048, and the number of carriers K = 1721.
Tables 2 and 3 are _{examples in the case where the LDPC block length N ldpc} = 64800 [bit], the number of FFT points is 8192, and the number of carriers K = 6881.
The serial numbers of each row in Table 1, Table 2, and Table 3 are added to the right end of each table for convenience.
Table 4 shows an example in which the LDPC block length N _ldpc = 44880 [bit], the number of FFT points is 2048, and the number of carriers K = 1721.
Table 5 shows an example in which the LDPC block length N _ldpc = 44880 [bit], the number of FFT points is 8192, and the number of carriers K = 6881.
The serial numbers of each row in Tables 4 and 5 are added to the right end of each table for convenience.
These parameter sets were searched within the following range. That is, the value of the frame length L is set to 200 or more and 500 or less. Further, the value of the number of data carriers D when the number of FFT points is 2048 is 1350 or more and 1440 or less. Further, the value of the number of data carriers D when the number of FFT points is 8192 is set to 624 or more and 6500 or less.

Parameters in [Case 2]:
When the number of modulation multi-values of the data carrier is limited, the conditions regarding the values of D and L can be relaxed.
If the number of modulation multi-values is limited to m even if the modulation method changes, those modulation multi-values are set to M1-1, M1-2, ..., M1_m. The amount of information Ns per data cell corresponding to these modulation multi-values is log ₂ (M1_1), log ₂ (M1_2), ..., Log ₂ (M1_m), respectively. When the greatest common divisor of these log ₂ (M1_1), log ₂ (M1_2), ..., Log _{2 (M1_m) is N bits} , the condition that D and L should satisfy is that Ns in the formula (1) is described above. It is expressed by the following equation (3), replaced with N _bits.

D × L × N _bits = n × N _ldpc・ ・ ・ (3)

When the condition of the equation (3) is satisfied, the number of LDPC blocks accommodated in one OFDM frame is exactly an integer regardless of whether the number of modulation multi-values is M1-1, M1-2, ..., M1_m. It becomes. When the greatest common divisor N _bits is 1, the equation (3) represents the same conditions as the equation (2). Unless the greatest common divisor N _bits is 1, the condition of the equation (3) is relaxed more than the condition of the equation (2). If the conditions are relaxed, that is, there are more combinations of D and L values.

For example, when the number of modulation multi-values is limited to 4 (QPSK), 16 (16QAM), 64 (64QAM), 256 (256QAM), the amount of information contained in one data cell is 2, 4, 8, respectively. It is 16 [bit]. In this case, the greatest common divisor of 2, 4, 8 and 16 is 2.

Table 6, Table 7, Table 8, Table 9, Table 10, Table 11, and Table 12 show the case 2 (when the number of modulation multi-values is limited to 2, 4, 8, 16) and the FFT points. This is an example of parameters that can be used when the number is 2048 or 8192. Further, an example of these parameters is the case where the LDPC block length N _ldpc = 64800 [bit] or N _ldpc = 44880 [bit]. The transmitter 1 constructs and transmits an OFDM frame using, for example, any of the parameters listed in these tables.
Table 6 shows an example in the case where the LDPC block length N _ldpc = 64800 [bit], the number of FFT points is 2048, and the number of carriers K = 1721.
Tables 7, 8 and 9 are _{examples in the case where the LDPC block length N ldpc} = 64800 [bit], the number of FFT points is 8192, and the number of carriers K = 6881.
The serial numbers of the rows of Tables 6, 7, 8, and 9 are added to the right end of each table for convenience.
Table 10 shows an example in which the LDPC block length N _ldpc = 44880 [bit], the number of FFT points is 2048, and the number of carriers K = 1721.
Tables 11 and 12 are _{examples in the case where the LDPC block length N ldpc} = 44880 [bit], the number of FFT points is 8192, and the number of carriers K = 6881.
The serial numbers of the rows of Tables 10, 11, and 12 are added to the right end of each table for convenience.

The parameter sets shown in Tables 6 to 12 are also searched within the same range as in Tables 1 to 5. That is, the value of the frame length L is set to 200 or more and 500 or less. Further, the value of the number of data carriers D when the number of FFT points is 2048 is 1350 or more and 1440 or less. Further, the value of the number of data carriers D when the number of FFT points is 8192 is set to 624 or more and 6500 or less.

The parameters used when applying the continuous pilot method have been described above. In each of "Case 1" and "Case 2", the transmission device 1 configures the OFDM frame so as to satisfy the above conditional expression.

As a result, on the receiving device side that receives the signal, as long as the OFDM frame can be synchronized, that is, if only the first symbol of the OFDM frame can be detected, a plurality of LDPC blocks arranged in the OFDM frame without using a complicated processing circuit. Can be detected sequentially. As a result, LDPC decoding becomes possible on the receiving device side. Further, since the LDPC block is arranged in the data cell in the OFDM frame without waste, the transmission efficiency can be maximized. Synchronous detection of OFDM frames can be performed using a TMCC carrier. Since the TMCC carrier is always arranged on a carrier having a constant frequency, monitoring the carrier enables synchronous detection of OFDM frames. A method for synchronous detection of OFDM frames by a TMCC carrier is described, for example, in the document "ARIB STD-B33 Portable OFDM Digital Radio Transmission System Standard for Transmission of Television Broadcast Program Material".

Next, a case where an OFDM frame in which pilot signals are distributed and arranged in both the frequency direction and the time direction will be described.
In the arrangement shown in FIG. 2, the pilot signal was assigned to the same carrier (frequency) at every symbol in the OFDM frame. In other words, the continuous pilot method was used.
Here, instead of the continuous pilot method, a scatterd pilot method is used in which the pilot carriers are distributed in both the frequency direction and the time direction. Similarly, in the case of this scatterd pilot method, the number of data carriers D and the symbol length L may be determined so that exactly an integer number of LDPC blocks are contained in the data cell portion in one OFDM frame.

FIG. 3 is a schematic view showing an example of arrangement of OFDM frames when the scattered pilot method is applied in the present embodiment. Also in this case, the horizontal axis is the frequency (carrier) direction, and the vertical axis is the time (symbol) direction. Then, one OFDM frame is composed of (L × K) cells in L rows and K columns. Further, carriers are assigned carrier numbers from 0 to K-1. Further, symbol numbers from 0 to L-1 are assigned to the symbols.

As shown in the figure, in this arrangement example, the carrier (frequency) on which the pilot signal is arranged is different for each symbol. Here, as an example, when moving from one symbol to the next, the carriers on which the pilot signals are arranged are shifted by two. Looking at some carriers in which the pilot signal can be placed, the insertion period of the pilot signal in the symbol direction is Nsp (Nsp is an integer greater than or equal to 2). That is, in the illustrated OFDM frame, the pilot cells are arranged so as to be dispersed in both the frequency direction and the time direction. The OFDM frame is a two-dimensional array of L rows and K columns. Then, in the two-dimensional array, pilot cells are arranged at intervals of Q lines in the frequency direction in each symbol, and pilot cells are arranged at intervals of Nsp symbols in the time direction in a carrier in which pilot cells can be arranged. Is placed.

Here, as an example, the case of Nsp = 4 is illustrated. Further, in this arrangement example, the frame length L is set to be an integral multiple of Nsp, which is the pilot insertion cycle. In other words, make L divisible by Nsp. As a result, even at the boundary portion between one OFDM frame and the next OFDM frame, the same pilot arrangement can always be obtained at the first symbol of the OFDM frame while maintaining the insertion period Nsp of the pilot signal. That is, the extraction of the pilot signal can be facilitated by setting L to be an integral multiple of Nsp.

Parameters in [Case 3]:
In this case, in order to fit exactly an integer number of LDPC blocks in one OFDM frame, the number D of data carriers and the OFDM frame length L must satisfy the condition of the following equation (4).

D × L = n × N _ldpc and L is an integer multiple of Nsp ... (4)

Also in this scatterd pilot method, the number of carriers K is set to (multiple of Q + 1). Q is again the pilot interval in the carrier direction. Also, the values of K, Q, and Nsp are determined so that an integral multiple of Nsp is Q.

Examples of specific parameter values are as follows.
When searching for a combination of parameter values under the same conditions as in "Case 1", the appropriate parameters in "Case 3" are Nsp among the parameters shown in Table 1, Table 2, Table 3, Table 4, and Table 5. It is a multiple of. When Nsp = 4, it is as follows.
That is, Tables 13, 14, 15, and 16 are examples of parameters that can be used in "Case 3" (where Nsp = 4) and when the number of FFT points is 2048 or 8192. Further, an example of these parameters is the case where the LDPC block length N _ldpc = 64800 [bit] or N _ldpc = 44880 [bit]. The transmitter 1 constructs and transmits an OFDM frame using, for example, any of the parameters listed in these tables.
Table 13 shows an example in the case where the LDPC block length N _ldpc = 64800 [bit], the number of FFT points is 2048, and the number of carriers K = 1721.
Table 14 shows an example in the case where the LDPC block length N _ldpc = 64800 [bit], the number of FFT points is 8192, and the number of carriers K = 6881.
The serial numbers of the rows of Tables 13 and 14 are added to the right end of each table for convenience.
Table 15 shows an example in which the LDPC block length N _ldpc = 44880 [bit], the number of FFT points is 2048, and the number of carriers K = 1721.
Table 16 shows an example in which the LDPC block length N _ldpc = 44880 [bit], the number of FFT points is 8192, and the number of carriers K = 6881.
The serial numbers of the rows of Tables 15 and 16 are added to the right end of each table for convenience.

Parameters in [Case 4]:
In "Case 4", Nsp OFDM frames that are continuous in time are treated as one super frame. Then, the pilot insertion cycle Nsp is maintained even if the OFDM frame is straddled. As a result, even if the frame length L of one OFDM frame is not a multiple of Nsp, the same pilot signal can always be arranged at the head symbol of the super frame. Therefore, on the receiving side, the pilot signal can be easily extracted.

In this case, the relationship between the number of data carriers D and the frame length L is such that the condition of the following equation (5) is satisfied. The conditions represented by the formula (5) are the same as the conditions represented by the formula (2) in the continuous pilot method.

D × L = n × N _ldpc・ ・ ・ (5)

In this case, the OFDM frame numbers (1, 2, ..., Nsp) indicating the order in the super frame are embedded in the TMCC signal of each OFDM frame constituting the super frame. This makes it possible to easily detect the OFDM frame (number 1) at the beginning of the super frame.

Since the above equation (5) is the same as the equation (2), the examples of the parameters that can be used by the transmitting device 1 in the “case 4” are the same as those in the “case 1”. That is, the example of the parameter in "Case 4" is the same as that shown in Table 1, Table 2, Table 3, Table 4, and Table 5.
That is, by using the super frame in "Case 4", parameters can be set from a wider range of candidates than in "Case 3".

Modification example of [Case 4]:
In "Case 4" described above, Nsp OFDM frames that are continuous in time are treated as one super frame. As a modification, here, Fs (Fs is a positive integer) OFDM frames are treated as one superframe. However, (Fs × L) is a multiple of Nsp. Further, also in this modification, the arrangement interval of the pilot cells is Nsp in a certain carrier in which the pilot cells are arranged. Then, this arrangement interval Nsp is maintained even at a location that straddles the boundary of the OFDM frame. As described above (Fs × L) is a multiple of Nsp, the carrier on which the pilot cell is arranged is always constant in the symbol at the beginning of the super frame.

That is, even in this example using the super frame, the pilot cells are arranged so as to be dispersed in both the frequency direction and the time direction. A superframe composed of Fs OFDM frames corresponds to a two-dimensional array of (L × Fs) rows and K columns. In each symbol in this super frame, pilot cells are arranged at intervals of Q lines in the frequency direction. In addition, the pilot cells are arranged at intervals of Nsp symbols in the time direction in the carrier in which the pilot cells can be arranged in this super frame. The pilot cell arrangement interval for each Nsp symbol is maintained even at a location in the super frame that straddles the boundary of the OFDM frame.

As an example, when L = 100, Fs = 2, Nsp = 8, (Fs × L) is a multiple of Nsp, so in the symbol at the beginning of the super frame, the carrier on which the pilot cell is placed is always It is constant.
The case where Nsp OFDM frames form one superframe is a special case when Fs OFDM frames form one superframe.

Next, a receiving device that receives a signal transmitted from the transmitting device 1 will be described.
FIG. 4 is a block diagram showing a schematic functional configuration of the receiving device. As shown in the figure, the receiving device 2 includes a receiving high frequency unit 51, an AD conversion unit 52, an orthogonal demodulation unit 53, an FFT unit 54, a switch 61, an OFDM frame configuration pattern storage unit 63, and a switch control unit 65. , TMCC signal reception processing unit 66, channel estimation unit 67, equalization processing unit 71, demodulation unit 72, LDPC decoder 73, and data output unit 74.

The reception high frequency unit 51 receives the radio signal transmitted from the transmission device 1 side and converts it into an intermediate frequency signal.
The AD conversion unit 52 converts the signal received by the reception high frequency unit 51 into analog-to-digital.
The orthogonal demodulation unit 53 converts the signal output from the AD conversion unit 52 into the amplitude (complex signal) of the in-phase component and the orthogonal component of the signal carrier wave.
The FFT unit 54 converts the complex signal in the time domain output from the orthogonal demodulation unit 53 into a signal in the frequency domain. Specifically, the FFT unit 54 performs a fast Fourier transform process.

The switch 61 inputs a signal from the FFT unit 54, switches between a data signal, a pilot signal, and a TMCC signal, and distributes the signals. The switch 61 switches based on the control signal from the switch control unit 65. As will be described later, the switch control unit 65 controls the switch 61 according to a predetermined OFDM frame configuration by referring to the OFDM frame configuration pattern storage unit 63.

The OFDM frame configuration pattern storage unit 63 stores information regarding the configuration of the OFDM frame, similarly to the OFDM frame configuration pattern storage unit 63 described in the transmission device 1. Specifically, the OFDM frame configuration pattern storage unit 63 stores information on carrier arrangement for each symbol in the OFDM frame.
The switch control unit 65 reads information on the configuration of the OFDM frame from the OFDM frame configuration pattern storage unit 63, and controls the switch 61 to distribute the signal of each carrier into a data signal, a pilot signal, and a TMCC signal for each symbol. To do.

The TMCC signal reception processing unit 66 processes the received TMCC signal.
When the receiving device 2 starts the receiving process, the OFDM frame synchronization is not established. Therefore, even if the receiving device 2 reads the carrier arrangement information from the OFDM frame configuration pattern storage unit 63, it generally determines which symbol in the OFDM frame the symbol being received at that time is. I can't figure it out. That is, normal distribution by the switch 61 cannot be performed. However, since the TMCC carrier is assigned to the same carrier number in every symbol, it can be normally received even if the OFDM frame synchronization is not established. Therefore, at the beginning of the reception processing, the TMCC signal reception processing unit 66 first processes the TMCC carrier to obtain OFDM frame synchronization (or, if a super frame is used, super frame synchronization can be obtained). , Transmission parameters can be detected.

The TMCC signal reception processing unit 66 includes a transmission parameter detection unit 661 and an OFDM frame synchronization detection unit 662.
The transmission parameter detection unit 661 detects the transmission parameter from the TMCC signal and supplies it to the demodulation unit 72.
The OFDM frame synchronization detection unit 662 takes an OFDM frame synchronization from the TMCC signal. When the above-mentioned super frame is used, the OFDM frame synchronization detection unit 662 takes an OFDM super frame synchronization from the TMCC signal. When the OFDM frame synchronization detection unit 662 synchronizes the OFDM frame (or OFDM super frame), the OFDM frame synchronization detection unit 662 supplies a synchronization signal to the switch control unit 65, the channel estimation unit 67, and the LDPC decoder 73. As a result, the receiving device 2 can normally proceed with the receiving process of the OFDM frame (or OFDM super frame). That is, the receiving device 2 can normally proceed with the receiving processing of not only the TMCC signal but also the data signal and the pilot signal.

That is, the TMCC signal reception processing unit 66 detects the synchronization of the OFDM frame and acquires the transmission parameter by acquiring the TMCC signal from the TMCC cell arranged in the OFDM frame.

The channel estimation unit 67 estimates the response (channel response) of the transmission line based on the received pilot signal. The pilot signal is a reference signal whose amplitude and phase are known. That is, the channel estimation unit 67 uses the received pilot signal (a complex number whose amplitude is the distance from the origin and whose phase is the angle of rotation) as a known original pilot signal (similarly, a complex number). Calculate the channel response by dividing. Further, the channel estimation unit 67 calculates the channel response by interpolation for the carrier portion other than the pilot carrier.
The equalization processing unit 71 equalizes the received data signal by complex division using the channel response estimated by the channel estimation unit 67.

The demodulation unit 72 demodulates the data signal after equalization by the equalization processing unit 71. As a result of demodulating the data cell, the demodulation unit 72 outputs a bit string corresponding to the data cell. The demodulation unit 72 can be regarded as performing parallel / serial conversion. That is, the demodulation unit 72 demodulates the data cells included in the OFDM frame based on the transmission parameters. Further, the demodulation unit 72 acquires exactly n LDPC blocks (n is an integer of 1 or more) per received OFDM frame, and supplies the LDPC blocks to the LDPC decoder 73.
The LDPC decoder 73 performs the LDPC decoding process based on the bit string output from the demodulation unit 72. Specifically, the LDPC decoder 73 identifies an LDPC block from a bit string output from the demodulation unit 72, and performs decoding processing in units of the LDPC block. The LDPC block length is N _ldpc [bit].
The data output unit 74 outputs the data decoded by the LDPC decoder 73 to the outside.

The receiving device 2 may be provided with a functional unit that performs bit deinterleaving processing, frequency deinterleaving processing, and time interleaving processing. These processes are reverse processing of bit interleaving processing, frequency interleaving processing, and time interleaving processing on the transmitting device 1 side, respectively. The bit deinterleaving process, the frequency deinterleaving process, and the time interleaving process itself can be performed by existing techniques. When these processes are added, it leads to improvement of multipath characteristics, mobile reception characteristics, and the like.

Parameters in [Case 5]:
In this "case 5", spatial multiplex MIMO (Multiple-Input Multiple-Output) is used as the wireless system. In MIMO system, the transmitting device transmits different information on the same frequency from a plurality of transmitting antennas. That is, the transmitting device transmits the OFDM frames shown in FIGS. 2 and 3 from each of the plurality of transmitting antennas. At this time, the formats of OFDM frames transmitted from different antennas are the same. However, the content (value) of the pilot signal transmitted from each transmitting antenna differs for each transmitting antenna. MIMO itself is an existing technology. Since existing techniques can be used for how to set the value of the pilot signal of each antenna and how to detect MIMO on the receiving device side, detailed description thereof will be omitted here.

The feature of this embodiment is the configuration of the OFDM frame when the MIMO method is used. In particular, a method of accommodating exactly an integer number of LDPC blocks in the entire OFDM frame (or OFDM superframe) corresponding to a plurality of transmitting antennas is a feature of the present embodiment. When the MIMO method is used, the LDPC block to be transmitted is distributed to the OFDM frames corresponding to each transmitting antenna.

FIG. 5 is a schematic view showing the relationship between the LDPC block and the OFDM frame when the LDPC block is transmitted by OFDM using the MIMO method. Here, the number of transmitting antennas is Nant. Nant is an integer greater than or equal to 2. Then, transmission antenna numbers 1, 2, ..., Nant are assigned to each transmission antenna. On the transmitting side, one LDPC block is divided into Nant sub-blocks. Each divided subblock corresponds to a transmitting antenna. Each subblock is housed in place within the OFDM frame for its respective transmitting antenna. One OFDM frame has a sub-block area corresponding to a plurality of LDPC blocks.
These sub-blocks are transmitted from each transmitting antenna and transmitted on the transmission path. Then, on the receiving side, each OFDM frame is restored from the received signal. Further, the LDPC subblock is taken out from each OFDM frame and reproduced as the original LDPC block.

That is, the functional configuration on the transmitter side is as follows. First, the LDPC encoder encodes the data to be transmitted by LDPC and outputs the LDPC block. Next, each LDPC block is divided into Nant sub-blocks. Then, the transmitting device 1 constitutes an OFDM frame for each transmitting antenna based on these Nant sub-blocks. The above subblocks are arranged in the data cells in the OFDM frame. The transmission device 1 arranges exactly an integer number of subblocks in one OFDM frame. The transmission device 1 also arranges a pilot signal and a TMCC signal in the OFDM frame. Then, the transmitting device 1 transmits those OFDM frames from each transmitting antenna.
That is, the OFDM frame generator in the transmitter divides the LDPC block into Nant subblocks, and corresponds to each transmitting antenna so that each divided subblock corresponds to Nant transmitting antennas. It is placed in the OFDM frame and contains exactly an integer number of subblocks in the data cell in the OFDM frame.

The configuration on the receiving device side is as follows. On the receiving device side, a plurality of antennas receive signals transmitted by the MIMO method from the transmitting device side. The receiving device then restores the OFDM frame for each transmitting antenna. Then, the receiving device extracts sub-blocks corresponding to the same LDPC block from the plurality of OFDM frames, and reproduces the LDPC block. Then, the LDPC decoder in the receiving device performs the LDPC decoding process and acquires the original data.

FIG. 6 is a schematic view showing an example of the configuration of the OFDM frame when the MIMO method is used. In the figure, as a representative, only the transmission signal (OFDM frame) of the transmission antenna 1 and the transmission signal (OFDM frame) of the transmission antenna Nant are shown, and the OFDM frame (from the transmission antenna 2 to the transmission antenna (transmission antenna 2) in the middle is shown. Up to Nant-1)) is omitted.
Each OFDM frame is composed of L symbols and K carriers, that is, (L × K) cells. One LDPC block is distributed and arranged from the OFDM frame of the transmitting antenna 1 to the OFDM frame of the transmitting antenna Nant. In the figure, Nant OFDM frames accommodate n (n is a positive integer) LDPC blocks (block numbers 1 to n).

The configuration of the OFDM frame shown in FIG. 6 is an example in which the continuous pilot method shown in FIG. 2 is a MIMO configuration.
In this example, in order to allocate n LDPC blocks to Nant OFDM frames corresponding to a plurality of antennas, the condition represented by the following equation (6) is satisfied.

Nant x D x L = n x N _ldpc ... (6)

When the condition of the equation (6) is satisfied, exactly an integer number of LDPC blocks can be arranged in data cells in Nant OFDM frames without waste.
The equation (6) is an equation obtained by multiplying the left side of the equation (2) in "Case 1" by Nant.

Similarly, the MIMO method can be applied corresponding to each of "case 2", "case 3", and "case 4".

When the MIMO method is applied to "Case 2", the following equation (7) is obtained by multiplying the left side of the equation (3) by Nant. When the number of modulation multi-values is limited, the transmitter may configure the OFDM frame according to this equation (7).

Nant x D x L x N _bits = n x N _ldpc ... (7)

Further, when the MIMO method is applied to the scattered pilot method of "Case 3", the following formula (8) is obtained by multiplying the left side of the above formula (4) by Nant. When the scatterd pilot method is used, the transmitting device may configure the OFDM frame according to this formula (8).

Nant × D × L = n × N _ldpc and L is an integer multiple of Nsp ... (8)

Further, when the MIMO method is applied to the method for defining and using the super frame of "Case 4", the following equation (9) is obtained by multiplying the left side of the equation (5) by Nant. In this case, the transmitting device may configure the OFDM frame according to this equation (9). As a result, the formula (9) is the same as the formula (6).

Nant x D x L = n x N _ldpc ... (9)

The transmitting device constitutes an OFDM frame using parameters satisfying the conditions in each of the cases of the equation (6), the equation (7), the equation (8), and the equation (9).
Table 17, Table 18, Table 19, Table 20, Table 21, Table 22, and Table 23 are based on the above equation (6) in "Case 5" and when the number of FFT points is 2048 or 8192. This is an example of the parameters that can be used. Further, an example of these parameters is the case where the LDPC block length N _ldpc = 64800 [bit] or N _ldpc = 44880 [bit]. The transmitter uses, for example, any of the parameters listed in these tables to configure and transmit OFDM frames.
The same parameter value can be used when the above equation (9) is followed in "Case 5".

Table 17 shows an example in the case where the LDPC block length N _ldpc = 64800 [bit], the number of FFT points is 2048, and the number of carriers K = 1721.
Table 18, Table 19, and Table 20 are _{examples in the case where the LDPC block length N ldpc} = 64800 [bit], the number of FFT points is 8192, and the number of carriers K = 6881.
The serial numbers of the rows of Table 17, Table 18, Table 19, and Table 20 are added to the right end of each table for convenience.
Table 21 shows an example in which the LDPC block length N _ldpc = 44880 [bit], the number of FFT points is 2048, and the number of carriers K = 1721.
Tables 22 and 23 are _{examples in the case where the LDPC block length N ldpc} = 44880 [bit], the number of FFT points is 8192, and the number of carriers K = 6881.
The serial numbers of the rows of Table 21, Table 22, and Table 23 are added to the right end of each table for convenience.

The function of the transmitting device or the receiving device in the above-described embodiment is realized by using an electric circuit / electronic circuit.

In addition, a part of the functions of the transmitting device or the receiving device in the above-described embodiment may be realized as a semiconductor chip. A chip is a semiconductor integrated circuit packaged with lead wires for signal input / output and lead wires for supplying power.
As an example, the LDPC encoder 12, the modulation unit 13, the pilot signal generation unit 16, the TMCC signal generation unit 17, the switch 21, the OFDM frame timing control unit 31, and the OFDM in the transmission device 1 (FIG. 1). It is configured as one chip including the functions of the frame configuration pattern storage unit 33 and the switch control unit 35. However, the chip may have functions other than those listed here, or may lack some of the functions listed here.
Further, as an example, the switch 61, the OFDM frame configuration pattern storage unit 63, the switch control unit 65, the TMCC signal reception processing unit 66, and the channel estimation unit 67 in the receiving device 2 (FIG. 4) are equalized. It is configured as one chip including the functions of the processing unit 71, the demodulation unit 72, and the LDPC decoder 73. However, the chip may have functions other than those listed here, or may lack some of the functions listed here.

It should be noted that at least a part of the functions of the transmitting device or the receiving device in the above-described embodiment may be realized by a computer. In that case, the program for realizing this control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by the computer system and executed. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk built in a computer system. Further, a "computer-readable recording medium" is a communication line for transmitting a program via a network such as the Internet or a communication line such as a telephone line, and dynamically holds the program for a short period of time. It may also include a program that holds a program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or a client in that case. Further, the above-mentioned program may be a program for realizing a part of the above-mentioned functions, and may be a program for realizing the above-mentioned functions in combination with a program already recorded in the computer system.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs and the like within a range that does not deviate from the gist of the present invention.

The present invention can be used for devices and the like for transmitting digital data by wireless signals and the like.

1 Transmitter 2 Receiver 11 Data acquisition unit 12 LDPC encoder 13 Modulation unit 16 Pilot signal generation unit 17 TMCC signal generation unit 21 Switch 31 OFDM frame timing control unit 33 OFDM frame configuration pattern storage unit (frame configuration pattern storage unit)
35 Switch control unit 41 IFFT unit 42 Orthogonal modulation unit 43 DA conversion unit 44 Transmission high frequency unit 51 Reception high frequency unit 52 AD conversion unit 53 Orthogonal demodulation unit 54 FFT unit 61 Switch 63 OFDM frame configuration pattern storage unit 65 Switch control unit 66 TMCC signal Reception processing unit 67 Channel estimation unit 71 Equalization processing unit 72 Demodulation unit 73 LDPC decoder 74 Data output unit 661 Transmission parameter detection unit 662 OFDM frame synchronization detection unit

Claims (28)

A transmitter that uses a plurality of carriers that are orthogonal to each other and transmits an OFDM frame composed of a predetermined number of symbols.
An LDPC encoder that encodes the data to be transmitted with LDPC and outputs an LDPC block,
In the OFDM frame, a data cell for transmitting the LDPC block output from the LDPC encoder, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information. And an OFDM frame generator that accommodates exactly n (n is an integer of 1 or more) LDPC blocks in the data cell included in one OFDM frame.
Equipped with
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The OFDM frame generator
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q, the pilot cells are arranged at regular intervals for each Q from the carriers at the ends of the K carriers in each of the symbols, and The pilot cells are continuously placed on a fixed carrier regardless of the symbol.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfy the condition
L number of the TMCC cell, place in the same carriers in the OFDM frame,
Transmitter. A transmitter that uses a plurality of carriers that are orthogonal to each other and transmits an OFDM frame composed of a predetermined number of symbols.
An LDPC encoder that encodes the data to be transmitted with LDPC and outputs an LDPC block,
In the OFDM frame, a data cell for transmitting the LDPC block output from the LDPC encoder, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information. And an OFDM frame generator that accommodates exactly n (n is an integer of 1 or more) LDPC blocks in the data cell included in one OFDM frame.
Equipped with
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The OFDM frame generator
When the number of modulation multi-values of the data cell is limited to m (m is an integer of 1 or more) of M1_1, M1-2, ..., M1_m, log ₂ (M1_1), log ₂ (M1-2), ...・ ・, The greatest common divisor of _{log 2 (M1_m) is N bits} .
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q, the pilot cells are arranged at regular intervals for each Q from the carriers at the ends of the K carriers in each of the symbols, and The pilot cells are continuously placed on a fixed carrier regardless of the symbol.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
N _bits × D × L = n × N _ldpc
Satisfy the condition
L number of the TMCC cell, place in the same carriers in the OFDM frame,
Transmitter. A transmitter that uses a plurality of carriers that are orthogonal to each other and transmits an OFDM frame composed of a predetermined number of symbols.
An LDPC encoder that encodes the data to be transmitted with LDPC and outputs an LDPC block,
In the OFDM frame, a data cell for transmitting the LDPC block output from the LDPC encoder, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information. And an OFDM frame generator that accommodates exactly n (n is an integer of 1 or more) LDPC blocks in the data cell included in one OFDM frame.
Equipped with
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The OFDM frame generator
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q
And based on the values of L and Nsp such that L is divisible by Nsp (Nsp is an integer of 2 or more)
In order to arrange the pilot cells in both the frequency direction and the time direction, the pilot cells are arranged at intervals of Q lines in the frequency direction in each of the symbols in the two-dimensional array of L rows and K columns. Moreover, in the carrier where the pilot cell can be arranged, the pilot cell is arranged at intervals of Nsp symbols in the time direction.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfy the condition
L number of the TMCC cell, place in the same carriers in the OFDM frame,
Transmitter. A transmitter that uses a plurality of carriers that are orthogonal to each other and transmits an OFDM frame composed of a predetermined number of symbols.
An LDPC encoder that encodes the data to be transmitted with LDPC and outputs an LDPC block,
In the OFDM frame, a data cell for transmitting the LDPC block output from the LDPC encoder, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information. And an OFDM frame generator that accommodates exactly n (n is an integer of 1 or more) LDPC blocks in the data cell included in one OFDM frame.
Equipped with
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The OFDM frame generator
Using the consecutive Fs (Fs is a positive integer) OFDM frames as superframes,
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q
In order to arrange the pilot cells in both the frequency direction and the time direction, in the two-dimensional arrangement of the (L × Fs) rows and K columns of the superframe consisting of the Fs OFDM frames, in each of the symbols. The pilot cells are arranged at intervals of Q lines in the frequency direction, and the pilots are arranged at intervals of Nsp symbols (Nsp is an integer of 2 or more) in the time direction in the carrier in which the pilot cells can be arranged. The cells are arranged, and the arrangement interval of the pilot cells for each of the Nsp symbols is maintained even at a location straddling the boundary of the OFDM frame.
(Fs × L) is a multiple of Nsp and
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfy the condition
The L TMCC cells are arranged on the same carrier in the OFDM frame, and the signal for detecting the OFDM frame at the head of the super frame is sent to the TMCC cell at a predetermined symbol in the head OFDM frame. place within,
Transmitter. It is a transmission device that transmits the OFDM frame by the spatial multiplex type MIMO of the spatial multiplex Nant (Nant is an integer of 2 or more).
The OFDM frame generator divides the LDPC block into Nant sub-blocks, and the OFDM frame corresponding to each transmitting antenna so that each of the divided sub-blocks corresponds to Nant transmitting antennas. Placed in, and exactly an integer number of said subblocks are housed in the data cell in said OFDM frame.
Each OFDM frame generated by the OFDM frame generator is transmitted from the respective transmitting antenna.
The transmitter according to any one of claims 1 to 4. The OFDM frame generator
A modulator that modulates the LDPC block output from the LDPC encoder and outputs a data signal for storing in the data cell, and a modulator.
A pilot signal generator that generates the pilot signal,
A TMCC signal generator that generates a TMCC signal containing at least the OFDM frame synchronization information,
A frame configuration pattern storage unit that stores arrangement information representing carriers for arranging the data cell, the pilot cell, and the TMCC cell for each symbol arranged in the OFDM frame in the time direction.
The data signal output from the modulation unit, the pilot signal output from the pilot signal generation unit, and the TMCC signal output from the TMCC signal generation unit are input, and the data is according to the control signal. A switch that switches and outputs a signal, the pilot signal, and the TMCC signal, and
The arrangement information is read from the frame configuration pattern storage unit for each symbol, the data signal is arranged in the data cell, the pilot signal is arranged in the pilot cell, and the TMCC signal is arranged in the TMCC cell. The switch control unit that supplies the control signal to the switch,
The transmitting device according to any one of claims 1 to 5, wherein the transmitter comprises. A receiving device that uses a plurality of carriers orthogonal to each other and receives an OFDM frame composed of a predetermined number of symbols.
A TMCC signal reception processing unit that detects synchronization of the OFDM frame and acquires transmission parameters by acquiring a TMCC signal from a TMCC cell arranged in the OFDM frame.
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit and
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding, and
Equipped with
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
Based on the values of K and Q such that (K-1) is divisible by Q, pilot cells are arranged at regular intervals for each Q from the carriers at the ends of the K carriers in each of the symbols. In addition, the pilot cells are continuously arranged on a fixed carrier regardless of the symbol.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfying the condition that,
Receiver. A receiving device that uses a plurality of carriers orthogonal to each other and receives an OFDM frame composed of a predetermined number of symbols.
A TMCC signal reception processing unit that detects synchronization of the OFDM frame and acquires transmission parameters by acquiring a TMCC signal from a TMCC cell arranged in the OFDM frame.
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit and
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding, and
Equipped with
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
The number of modulation multi-values of the data cell is limited to m (m is an integer of 1 or more) of M1_1, M1-2, ..., M1_m, and log ₂ (M1_1), log ₂ (M1_2), ... , Log ₂ (M1_m) has the greatest common divisor as N _bits .
Based on the values of K and Q such that (K-1) is divisible by Q, in each of the symbols, pilot cells are arranged at regular intervals for each Q from the carrier at the end of the K carriers, and the symbols The pilot cells are continuously arranged on a certain carrier regardless of the above.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
N _bits × D × L = n × N _ldpc
Satisfying the condition that,
Receiver. A receiving device that uses a plurality of carriers orthogonal to each other and receives an OFDM frame composed of a predetermined number of symbols.
A TMCC signal reception processing unit that detects synchronization of the OFDM frame and acquires transmission parameters by acquiring a TMCC signal from a TMCC cell arranged in the OFDM frame.
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit and
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding, and
Equipped with
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
Based on the values of K and Q such that (K-1) is divisible by Q
And based on the values of L and Nsp such that L is divisible by Nsp (Nsp is an integer of 2 or more)
Pilot cells are arranged in both the frequency direction and the time direction, and in the two-dimensional arrangement of L rows and K columns, the pilot cells are arranged at intervals of Q lines in the frequency direction for each of the symbols. In the carrier where the pilot cell can be arranged, the pilot cell is arranged at intervals of Nsp symbols in the time direction.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfying the condition that,
Receiver. A receiving device that uses a plurality of carriers orthogonal to each other and receives an OFDM frame composed of a predetermined number of symbols.
A TMCC signal reception processing unit that detects synchronization of the OFDM frame and acquires transmission parameters by acquiring a TMCC signal from a TMCC cell arranged in the OFDM frame.
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit and
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding, and
Equipped with
The OFDM frame of consecutive Fs (Fs is a positive integer) is a super frame.
The TMCC signal reception processing unit detects the synchronization of the super frame based on the TMCC signal.
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
Based on the values of K and Q such that (K-1) is divisible by Q
Pilot cells are arranged in both the frequency direction and the time direction, and in a two-dimensional arrangement of (L × Fs) rows and K columns of the superframe consisting of the Fs OFDM frames, the frequency direction is used for each of the symbols. The pilot cells are arranged at intervals of Q lines, and the pilot cells are arranged at intervals of Nsp symbols (Nsp is an integer of 2 or more) in the time direction in the carrier in which the pilot cells can be arranged. The arrangement interval of the pilot cells for each of the Nsp symbols is maintained even at a location that is arranged and straddles the boundary of the OFDM frame.
(Fs × L) is a multiple of Nsp and
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfying the condition that,
Receiver. It is a receiving device that receives the OFDM frame transmitted by the spatial multiplexing MIMO of the spatial multiplex Nant (Nant is an integer of 2 or more).
The demodulation unit acquires subblocks from each data cell of the Nant number of the OFDM frames corresponding to the spatial multiplex.
The LDPC decoder performs LDPC decoding processing on the LDPC blocks restored from the Nant sub-blocks.
The receiving device according to any one of claims 7 to 10. This is a frame configuration method for constructing an OFDM frame for transmitting an LDPC code as an internal code in an OFDM system.
In the OFDM frame, a data cell for transmitting an LDPC-encoded LDPC block, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information are arranged. and, (the n 1 or more integer) exactly n times in said data cells contained in one of the OFDM frame is intended for accommodating the LDPC blocks,
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q, the pilot cells are arranged at regular intervals for each Q from the carriers at the ends of the K carriers in each of the symbols, and The pilot cells are continuously placed on a fixed carrier regardless of the symbol.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfy the condition
The L TMCC cells are placed on the same carrier in the OFDM frame.
Frame configuration method. This is a frame configuration method for constructing an OFDM frame for transmitting an LDPC code as an internal code in an OFDM system.
In the OFDM frame, a data cell for transmitting an LDPC-encoded LDPC block, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information are arranged. Moreover, exactly n (n is an integer of 1 or more) of the LDPC blocks are accommodated in the data cell included in one OFDM frame .
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
When the number of modulation multivalues of the data cell is limited to m (m is an integer of 1 or more) of M1_1, M1-2, ..., M1_m, log ₂ (M1_1), log ₂ (M1-2), ...・ ・, The greatest common divisor of _{log 2 (M1_m) is N bits} .
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q, the pilot cells are arranged at regular intervals for each Q from the carriers at the ends of the K carriers in each of the symbols, and The pilot cells are continuously placed on a fixed carrier regardless of the symbol.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
N _bits × D × L = n × N _ldpc
Satisfy the condition
The L TMCC cells are placed on the same carrier in the OFDM frame.
How to configure the frame. This is a frame configuration method for constructing an OFDM frame for transmitting an LDPC code as an internal code in an OFDM system.
In the OFDM frame, a data cell for transmitting an LDPC-encoded LDPC block, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information are arranged. Moreover, exactly n (n is an integer of 1 or more) of the LDPC blocks are accommodated in the data cell included in one OFDM frame .
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q
And based on the values of L and Nsp such that L is divisible by Nsp (Nsp is an integer of 2 or more)
In order to arrange the pilot cells in both the frequency direction and the time direction, the pilot cells are arranged at intervals of Q lines in the frequency direction in each of the symbols in the two-dimensional array of L rows and K columns. Moreover, in the carrier where the pilot cell can be arranged, the pilot cell is arranged at intervals of Nsp symbols in the time direction.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfy the condition
The L TMCC cells are placed on the same carrier in the OFDM frame.
How to configure the frame. This is a frame configuration method for constructing an OFDM frame for transmitting an LDPC code as an internal code in an OFDM system.
In the OFDM frame, a data cell for transmitting an LDPC-encoded LDPC block, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least OFDM frame synchronization information are arranged. Moreover, exactly n (n is an integer of 1 or more) of the LDPC blocks are accommodated in the data cell included in one OFDM frame .
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
Using the consecutive Fs (Fs is a positive integer) OFDM frames as superframes,
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q
In order to arrange the pilot cells in both the frequency direction and the time direction, in the two-dimensional arrangement of the (L × Fs) rows and K columns of the superframe consisting of the Fs OFDM frames, in each of the symbols. The pilot cells are arranged at intervals of Q lines in the frequency direction, and the pilots are arranged at intervals of Nsp symbols (Nsp is an integer of 2 or more) in the time direction in the carrier in which the pilot cells can be arranged. The cells are arranged, and the arrangement interval of the pilot cells for each of the Nsp symbols is maintained even at a location straddling the boundary of the OFDM frame.
(Fs × L) is a multiple of Nsp and
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfy the condition
The L TMCC cells are arranged on the same carrier in the OFDM frame, and the signal for detecting the OFDM frame at the head of the super frame is sent to the TMCC cell at a predetermined symbol in the head OFDM frame. Place inside,
How to configure the frame. An LDPC encoder that encodes the data to be transmitted with LDPC and outputs an LDPC block,
In the OFDM frame, a data cell for transmitting the LDPC block output from the LDPC encoder, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least the OFDM frame synchronization information are included. An OFDM frame generator that is arranged and accommodates exactly n (n is an integer of 1 or more) LDPC blocks in the data cell included in one OFDM frame.
Equipped with
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The OFDM frame generator
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q, the pilot cells are arranged at regular intervals for each Q from the carriers at the ends of the K carriers in each of the symbols, and The pilot cells are continuously placed on a fixed carrier regardless of the symbol.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfy the condition
The L TMCC cells are placed on the same carrier in the OFDM frame.
Tip. An LDPC encoder that encodes the data to be transmitted with LDPC and outputs an LDPC block,
In the OFDM frame, a data cell for transmitting the LDPC block output from the LDPC encoder, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least the OFDM frame synchronization information are included. An OFDM frame generator that is arranged and accommodates exactly n (n is an integer of 1 or more) LDPC blocks in the data cell included in one OFDM frame.
Equipped with
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The OFDM frame generator
Log when the number of modulation multi-values of the data cell is limited to m (m is an integer of 1 or more) of M1_1, M1-2, ..., M1_m. ₂ (M1_1), log ₂ (M1-2), ..., log ₂ The greatest common divisor of (M1_m) is N _bits age,
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q, the pilot cells are arranged at regular intervals for each Q from the carriers at the ends of the K carriers in each of the symbols, and The pilot cells are continuously placed on a fixed carrier regardless of the symbol.
The number of data cells for each symbol is D, and the code length of the LDPC block is N. _ldpc When it is a bit
N _bits × D × L = n × N _ldpc
Satisfy the condition
The L TMCC cells are placed on the same carrier in the OFDM frame.
Tip. An LDPC encoder that encodes the data to be transmitted with LDPC and outputs an LDPC block,
In the OFDM frame, a data cell for transmitting the LDPC block output from the LDPC encoder, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least the OFDM frame synchronization information are included. An OFDM frame generator that is arranged and accommodates exactly n (n is an integer of 1 or more) LDPC blocks in the data cell included in one OFDM frame.
Equipped with
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The OFDM frame generator
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q
And based on the values of L and Nsp such that L is divisible by Nsp (Nsp is an integer of 2 or more)
In order to arrange the pilot cells in both the frequency direction and the time direction, the pilot cells are arranged at intervals of Q lines in the frequency direction in each of the symbols in the two-dimensional array of L rows and K columns. Moreover, in the carrier where the pilot cell can be arranged, the pilot cell is arranged at intervals of Nsp symbols in the time direction.
The number of data cells for each symbol is D, and the code length of the LDPC block is N. _ldpc When it is a bit
D × L = n × N _ldpc
Satisfy the condition
The L TMCC cells are placed on the same carrier in the OFDM frame.
Tip. An LDPC encoder that encodes the data to be transmitted with LDPC and outputs an LDPC block,
In the OFDM frame, a data cell for transmitting the LDPC block output from the LDPC encoder, a pilot cell for transmitting a pilot signal as a demodulation reference, and a TMCC cell containing at least the OFDM frame synchronization information are included. An OFDM frame generator that is arranged and accommodates exactly n (n is an integer of 1 or more) LDPC blocks in the data cell included in one OFDM frame.
Equipped with
The OFDM frame is composed of (K × L) cells having a number of carriers K in the frequency direction and a number L of symbols in the time direction.
The OFDM frame generator
Using the consecutive Fs (Fs is a positive integer) OFDM frames as superframes,
The effective symbol length of the symbol is Te, the guard interval length is Tg, and the guard interval ratio R, which is the ratio of the guard interval length to the effective symbol length, is Tg / Te.
Let M be the maximum integer equal to or less than the reciprocal 1 / R of the guard interval ratio R.
When an integer less than or equal to M is Q,
Based on the values of K and Q such that (K-1) is divisible by Q
In order to arrange the pilot cells in both the frequency direction and the time direction, in the two-dimensional arrangement of the (L × Fs) rows and K columns of the superframe consisting of the Fs OFDM frames, in each of the symbols. The pilot cells are arranged at intervals of Q lines in the frequency direction, and the pilots are arranged at intervals of Nsp symbols (Nsp is an integer of 2 or more) in the time direction in the carrier in which the pilot cells can be arranged. The cells are arranged, and the arrangement interval of the pilot cells for each of the Nsp symbols is maintained even at a location straddling the boundary of the OFDM frame.
(Fs × L) is a multiple of Nsp and
The number of data cells for each symbol is D, and the code length of the LDPC block is N. _ldpc When it is a bit
D × L = n × N _ldpc
Satisfy the condition
The L TMCC cells are arranged on the same carrier in the OFDM frame, and the signal for detecting the OFDM frame at the head of the super frame is sent to the TMCC cell at a predetermined symbol in the head OFDM frame. Place inside,
Tip. By acquiring the TMCC signal from the TMCC cell arranged in the OFDM frame, the TMCC signal reception processing unit that detects the synchronization of the OFDM frame and acquires the transmission parameter,
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit and
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding, and
Equipped with
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
Based on the values of K and Q such that (K-1) is divisible by Q, pilot cells are arranged at regular intervals for each Q from the carriers at the ends of the K carriers in each of the symbols. In addition, the pilot cells are continuously arranged on a fixed carrier regardless of the symbol.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfy the condition,
Tip. By acquiring the TMCC signal from the TMCC cell arranged in the OFDM frame, the TMCC signal reception processing unit that detects the synchronization of the OFDM frame and acquires the transmission parameter,
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit and
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding, and
Equipped with
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
The number of modulation multi-values of the data cell is limited to m (m is an integer of 1 or more) of M1_1, M1-2, ..., M1_m, and log. ₂ (M1_1), log ₂ (M1-2), ..., log ₂ The greatest common divisor of (M1_m) is N _bits age,
Based on the values of K and Q such that (K-1) is divisible by Q, in each of the symbols, pilot cells are arranged at regular intervals for each Q from the carrier at the end of the K carriers, and the symbols The pilot cells are continuously arranged on a certain carrier regardless of the above.
The number of data cells for each symbol is D, and the code length of the LDPC block is N. _ldpc When it is a bit
N _bits × D × L = n × N _ldpc
Satisfy the condition,
Tip. By acquiring the TMCC signal from the TMCC cell arranged in the OFDM frame, the TMCC signal reception processing unit that detects the synchronization of the OFDM frame and acquires the transmission parameter,
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit and
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding, and
Equipped with
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
Based on the values of K and Q such that (K-1) is divisible by Q
And based on the values of L and Nsp such that L is divisible by Nsp (Nsp is an integer of 2 or more)
Pilot cells are arranged in both the frequency direction and the time direction, and in the two-dimensional arrangement of L rows and K columns, the pilot cells are arranged at intervals of Q lines in the frequency direction for each of the symbols. In the carrier where the pilot cell can be arranged, the pilot cell is arranged at intervals of Nsp symbols in the time direction.
The number of data cells for each symbol is D, and the code length of the LDPC block is N. _ldpc When it is a bit
D × L = n × N _ldpc
Satisfy the condition,
Tip. By acquiring the TMCC signal from the TMCC cell arranged in the OFDM frame, the TMCC signal reception processing unit that detects the synchronization of the OFDM frame and acquires the transmission parameter,
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit and
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding, and
Equipped with
The OFDM frame of consecutive Fs (Fs is a positive integer) is a super frame.
The TMCC signal reception processing unit detects the synchronization of the super frame based on the TMCC signal.
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
Based on the values of K and Q such that (K-1) is divisible by Q
Pilot cells are arranged in both the frequency direction and the time direction, and in a two-dimensional arrangement of (L × Fs) rows and K columns of the superframe consisting of the Fs OFDM frames, the frequency direction is used for each of the symbols. The pilot cells are arranged at intervals of Q lines, and the pilot cells are arranged at intervals of Nsp symbols (Nsp is an integer of 2 or more) in the time direction in the carrier in which the pilot cells can be arranged. The arrangement interval of the pilot cells for each of the Nsp symbols is maintained even at a location that is arranged and straddles the boundary of the OFDM frame.
(Fs × L) is a multiple of Nsp and
The number of data cells for each symbol is D, and the code length of the LDPC block is N. _ldpc When it is a bit
D × L = n × N _ldpc
Satisfy the condition,
Tip. On your computer,
The frame configuration method according to any one of claims 12 to 15.
Program Ru allowed to run. Computer,
A TMCC signal reception processing unit that detects synchronization of the OFDM frame and acquires transmission parameters by acquiring a TMCC signal from a TMCC cell arranged in the OFDM frame.
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit,
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding.
It is a program that functions as
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
Based on the values of K and Q such that (K-1) is divisible by Q, pilot cells are arranged at regular intervals for each Q from the carriers at the ends of the K carriers in each of the symbols. In addition, the pilot cells are continuously arranged on a fixed carrier regardless of the symbol.
When the number of data cells for each symbol is D and the code length of the LDPC block is N _ldpc bit,
D × L = n × N _ldpc
Satisfy the condition,
program. Computer,
A TMCC signal reception processing unit that detects synchronization of the OFDM frame and acquires transmission parameters by acquiring a TMCC signal from a TMCC cell arranged in the OFDM frame.
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit,
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding.
It is a program that functions as
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
The number of modulation multi-values of the data cell is limited to m (m is an integer of 1 or more) of M1_1, M1-2, ..., M1_m, and log. ₂ (M1_1), log ₂ (M1-2), ..., log ₂ The greatest common divisor of (M1_m) is N _bits age,
Based on the values of K and Q such that (K-1) is divisible by Q, in each of the symbols, pilot cells are arranged at regular intervals for each Q from the carrier at the end of the K carriers, and the symbols The pilot cells are continuously arranged on a certain carrier regardless of the above.
The number of data cells for each symbol is D, and the code length of the LDPC block is N. _ldpc When it is a bit
N _bits × D × L = n × N _ldpc
Satisfy the condition,
program. Computer,
A TMCC signal reception processing unit that detects synchronization of the OFDM frame and acquires transmission parameters by acquiring a TMCC signal from a TMCC cell arranged in the OFDM frame.
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit,
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding.
It is a program that functions as
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
Based on the values of K and Q such that (K-1) is divisible by Q
And based on the values of L and Nsp such that L is divisible by Nsp (Nsp is an integer of 2 or more)
Pilot cells are arranged in both the frequency direction and the time direction, and in the two-dimensional arrangement of L rows and K columns, the pilot cells are arranged at intervals of Q lines in the frequency direction for each of the symbols. In the carrier where the pilot cell can be arranged, the pilot cell is arranged at intervals of Nsp symbols in the time direction.
The number of data cells for each symbol is D, and the code length of the LDPC block is N. _ldpc When it is a bit
D × L = n × N _ldpc
Satisfy the condition,
program. Computer,
A TMCC signal reception processing unit that detects synchronization of the OFDM frame and acquires transmission parameters by acquiring a TMCC signal from a TMCC cell arranged in the OFDM frame.
Based on the transmission parameters, the data cells included in the OFDM frame are demodulated, and exactly n LDPC blocks (n is an integer of 1 or more) contained in each OFDM frame are acquired from the data cells. Demodulation unit,
An LDPC decoder that performs LDPC decoding processing on the LDPC block acquired by the demodulation unit to acquire data before LDPC coding.
It is a program that functions as
The OFDM frame of consecutive Fs (Fs is a positive integer) is a super frame.
The TMCC signal reception processing unit detects the synchronization of the super frame based on the TMCC signal.
The received OFDM frame is
It is composed of (K × L) cells having K carriers in the frequency direction and L symbols in the time direction.
Based on the values of K and Q such that (K-1) is divisible by Q
Pilot cells are arranged in both the frequency direction and the time direction, and in a two-dimensional arrangement of (L × Fs) rows and K columns of the superframe consisting of the Fs OFDM frames, the frequency direction is used for each of the symbols. The pilot cells are arranged at intervals of Q lines, and the pilot cells are arranged at intervals of Nsp symbols (Nsp is an integer of 2 or more) in the time direction in the carrier in which the pilot cells can be arranged. The arrangement interval of the pilot cells for each of the Nsp symbols is maintained even at a location that is arranged and straddles the boundary of the OFDM frame.
(Fs × L) is a multiple of Nsp and
The number of data cells for each symbol is D, and the code length of the LDPC block is N. _ldpc When it is a bit
D × L = n × N _ldpc
Satisfy the condition,
program.

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