Transmitting apparatus, receiving apparatus, communication system, control circuit, storage medium, transmitting method, receiving method, and signal processing method

Abstract

A transmission device (10) for orthogonal frequency division multiplexing communication includes a subcarrier mapping section (113) that copies a subcarrier signal sequence and maps the copied subcarrier signal sequences at equal subcarrier intervals, and a transmission phase rotation section (114) that divides each of the subcarrier signal sequences mapped at the subcarrier intervals into two or more subsets and imparts a phase rotation that makes each of the subsets a different time timing to each of the subsets.

Description

Technical Field

[0001] This disclosure relates to a transmitting device, a receiving device, a communication system, a control circuit, a storage medium, a transmitting method, a receiving method, and a signal processing method for performing OFDM (Orthogonal Frequency Division Multiplexing) communication. Background Technology

[0002] OFDM communication, used in wireless LANs (Local Area Networks), is a transmission method with strong resistance to multipath delay and the ability to achieve wide bandwidth. However, concerns arise regarding the degradation of reception quality due to factors such as frequency selectivity in the transmission path leading to communication quality degradation, and the superposition of non-negligible interference within the signal band onto the received signal. As a countermeasure to the sharp decline in communication quality caused by frequency selective fading in the transmission path, frequency diversity transmission, which transmits the same signal using multiple subcarriers, is being researched. Frequency diversity transmission is the optimal transmission method in open-loop systems where the transmitting device replicates the subcarrier signal sequence at equal intervals and maps it for transmission to address the degradation of communication quality in unknown transmission paths. This transmission method will be referred to as frequency repetition.

[0003] Frequency repetition, for example, involves copying a subcarrier signal sequence of length L into M subcarriers and then distributing these M subcarrier signal sequences at equal intervals of subcarrier spacing D. By applying frequency repetition, the communication quality and interference tolerance in the aforementioned transmission path can be improved. However, since frequency repetition copies the same signal across multiple subcarriers, there is a problem of deterioration in the peak-to-average power ratio (PAPR) of the transmitted waveform after the inverse Discrete Fourier transform, resulting in reduced transmission power efficiency. Various studies have been conducted on peak-shaving strategies for the transmitted waveform in transmitting devices. For example, Patent Document 1 discloses a technique for wireless communication devices that ensures signal quality while maintaining high amplifier efficiency even when the modulation scheme is adaptively changed.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 4905463 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, the aforementioned prior art is a technique for counteracting peaks in general transmission waveforms, and it has the problem that it neither discloses nor implies counteracting peaks in transmission waveforms specific to frequency repetition.

[0009] This disclosure was made in view of the above circumstances, and its purpose is to provide a transmitting device that, in the case of frequency repetition in OFDM communication applications, can suppress the deterioration of the peak-to-average power ratio of the transmitted waveform and suppress the reduction of the transmission power efficiency.

[0010] Methods for solving problems

[0011] To address the aforementioned issues and achieve the objective, the present invention provides a transmitting apparatus for orthogonal frequency division multiplexing (OFDM) communication. The transmitting apparatus is characterized by comprising: a subcarrier mapping unit that replicates a subcarrier signal sequence and maps the replicated subcarrier signal sequence at equal subcarrier intervals; and a transmission phase rotation unit that divides each subcarrier signal sequence mapped at subcarrier intervals into two or more subsets and assigns a phase rotation to each subset such that each subset has a different time timing.

[0012] Invention Effects

[0013] The transmitting device of the present invention has the following effects: when the frequency of OFDM communication is repeated, it can suppress the deterioration of the peak-to-average power ratio of the transmitted waveform and suppress the reduction of the transmission power efficiency. Attached Figure Description

[0014] Figure 1 This is a diagram illustrating a structural example of the communication system according to Embodiment 1.

[0015] Figure 2 This is a flowchart illustrating the operation of the transmitting device in Embodiment 1.

[0016] Figure 3 This is a flowchart illustrating the operation of the receiving device in Embodiment 1.

[0017] Figure 4 This is a diagram illustrating, as a comparative example, the signal waveform of a subcarrier signal sequence obtained by a transmitting device without phase rotation and the signal waveform of a time signal block after being transformed by IDFT (Inverse Discrete Fourier Transform).

[0018] Figure 5 This is a diagram illustrating an example of the signal waveform of the subcarrier signal sequence obtained by the transmitting device of the communication system in Embodiment 1 and the signal waveform of the time signal block after IDFT transformation.

[0019] Figure 6 This is a diagram illustrating an example of the complementary cumulative distribution function characteristics of the instantaneous normalized signal power obtained by the communication system in Implementation 1.

[0020] Figure 7 This is a diagram illustrating an example of the structure of a processing circuit in Embodiment 1, which comprises a processor and a memory to implement a transmission device.

[0021] Figure 8 This diagram illustrates an example of a processing circuit used in Embodiment 1 to implement the processing circuit of the transmitting device using dedicated hardware.

[0022] Figure 9 This is a diagram illustrating a structural example of the communication system according to Embodiment 2. Detailed Implementation

[0023] Hereinafter, based on the accompanying drawings, the transmitting apparatus, receiving apparatus, communication system, control circuit, storage medium, transmitting method, receiving method, and signal processing method of the present disclosure will be described in detail.

[0024] Implementation method 1.

[0025] Figure 1 This is a diagram illustrating a structural example of the communication system 1 according to Embodiment 1. The communication system 1 includes a transmitting device 10 and a receiving device 20. The communication system 1 is a system in which the transmitting device 10 and the receiving device 20 perform wireless communication using OFDM communication with frequency repetition. In the following description, OFDM communication will sometimes be referred to as Orthogonal Frequency Division Multiplexing (OFDM) communication. Furthermore, in... Figure 1 The diagram shows an example of a communication system 1 having one transmitting device 10 and one receiving device 20, but it is not limited thereto. The communication system 1 may also have multiple transmitting devices 10 and multiple receiving devices 20.

[0026] The transmitting device 10 includes: a transmitting baseband processing unit 110 that generates a baseband signal based on a transmitting bit sequence; a transmitting RF (Radio Frequency) unit 120 that converts the baseband signal generated by the transmitting baseband processing unit 110 into a high-frequency signal; and a transmitting antenna 130 that transmits the high-frequency signal converted by the transmitting RF unit 120. The transmitting baseband processing unit 110 includes an encoding unit 111, a primary modulation unit 112, a subcarrier mapping unit 113, a transmitting phase rotation unit 114, an IDFT unit 115, a GI (Guard Interval) addition unit 116, a transmitting waveform shaping unit 117, and a DAC (Digital-to-Analog Conversion) unit 118. Figure 2 This is a flowchart illustrating the operation of the transmitting device 10 in Embodiment 1.

[0027] The encoding unit 111 applies error correction coding and other encoding processes to the transmitted bit sequence (step S11). The primary modulation unit 112 maps the transmitted bit sequence I / Q encoded by the encoding unit 111 to PSK (Phase Shift Keying) modulation signals, QAM (Quadrature Amplitude Modulation) modulation signals, etc. (step S12). The subcarrier mapping unit 113 copies the primary modulation signal sequence of length L into M copies and maps them to subcarriers (step S13). That is, the subcarrier mapping unit 113 copies the subcarrier signal sequence and maps the copied multiple subcarrier signal sequences with equal subcarrier intervals D. In addition, M is an integer greater than or equal to 1, and D is an integer greater than or equal to 1. The unit of the subcarrier interval D is the same as the unit of the length L of the subcarrier signal sequence. In addition, since the length of the primary modulation signal sequence, i.e., the subcarrier signal sequence, is L, the subcarrier interval D is set to an integer D ≥ L. The transmitting phase rotation unit 114 divides each subcarrier signal sequence mapped by the subcarrier interval D into two or more subsets, and assigns a phase rotation to each subset so that each subset is timed differently (step S14). The detailed operation of the transmitting phase rotation unit 114 will be described later.

[0028] IDFT unit 115 transforms the subcarrier signal sequence, i.e., the subcarrier signal block, after phase rotation by transmit phase rotation unit 114, into a time signal block using IDFT (step S15). GI addition unit 116 adds a guard interval, i.e., GI, to each time signal block (step S16). Transmit waveform shaping unit 117 performs digital front-end processing on the time signal blocks after GI addition, including upsampling, digital filtering, and quadrature transformation (step S17). DAC unit 118 performs digital-to-analog conversion on the time signal blocks after digital front-end processing (step S18) and outputs a baseband signal.

[0029] The receiving device 20 receives a subcarrier signal sequence transmitted from the transmitting device 10 performing OFDM communication. The receiving device 20 includes: a receiving antenna 230 that receives high-frequency signals; a receiving RF unit 220 that converts the high-frequency signals received by the receiving antenna 230 into baseband signals; and a receiving baseband processing unit 210 that generates a received bit sequence based on the baseband signals. The receiving baseband processing unit 210 includes an ADC (Analog-to-Digital Conversion) unit 218, a receiving waveform shaping unit 217, a GI removal unit 216, a DFT (Discrete Fourier Transform) unit 215, a receiving phase rotation unit 214, a subcarrier demapping unit 213, a primary demodulation unit 212, and a decoding unit 211. Figure 3This is a flowchart illustrating the operation of the receiving device 20 in Embodiment 1.

[0030] The ADC unit 218 performs analog-to-digital conversion on the baseband signal (step S21). The received waveform shaping unit 217 performs digital front-end processing on the digitally converted time signal, including quadrature demodulation, digital filtering, and downsampling (step S22). The GI removal unit 216 removes GI from each time signal block after digital front-end processing (step S23) and extracts the DFT target block. The DFT unit 215 transforms the GI-removed time signal block into a subcarrier signal block using DFT (step S24).

[0031] The receiving phase rotation unit 214 compensates for the phase rotation in the transmitting device 10 by inverting the phase of the received subcarrier signal block, i.e., the subcarrier signal sequence, by the amount of phase rotation given by the transmitting device 10 (step S25). The subcarrier demapping unit 213 synthesizes the subcarrier signal sequence, which has been copied into M subcarrier signals by the transmitting device 10 (step S26) and extracts it as the I / Q signal to be demodulated. That is, the subcarrier demapping unit 213 synthesizes the subcarrier signal sequence after the phase rotation is compensated by the receiving phase rotation unit 214 and extracts it as the demodulated signal. The primary demodulation unit 212 performs PSK demodulation, QAM demodulation, etc., on the I / Q signal and calculates the soft decision value or hard decision value (step S27). The decoding unit 211 performs decoding processing such as error correction decoding on the soft decision value or hard decision value (step S28) and outputs the received bit sequence.

[0032] Furthermore, the inverse discrete Fourier transform of the IDFT unit 115 of the transmitting device 10 is assumed to be an IFFT (Inverse Fast Fourier Transform) with a power of 2. Similarly, the discrete Fourier transform of the DFT unit 215 of the receiving device 20 is assumed to be an FFT (Fast Fourier Transform) with a power of 2.

[0033] Here, before explaining the effects obtained by the communication system 1 of this embodiment, namely the transmitting device 10 and the receiving device 20, the issue of frequency repetition previously described in the background art will be explained using the accompanying drawings. Figure 4 This diagram illustrates, as a comparative example, the signal waveforms of a subcarrier signal sequence obtained by a transmitting device without phase rotation and the signal waveforms of a time signal block after IDFT transformation. The transmitting device without phase rotation is, for example, from... Figure 1 The transmitting device 10 shown omits the transmitting phase rotation unit 114. Figure 4 In the image, the left side shows the signal waveform of the subcarrier signal sequence, and the right side shows the signal waveform of the time signal block after IDFT transformation. Figure 4 The signal waveform of the subcarrier signal sequence on the left shows an example of copying a subcarrier signal sequence of length L into 3 copies with equal subcarrier intervals D, assuming the number of copies M=3.

[0034] A subcarrier signal sequence of length L is exemplified as a single signal block with continuous frequency, but it is not limited to this; the subcarrier signal sequence of length L can also be dispersed. However, since the subcarrier signal sequence of length L is mapped at equal intervals of subcarrier spacing D, the condition is that adjacent signal blocks and the subcarriers to be mapped do not repeat. When performing an N-point IDFT on a subcarrier signal sequence with frequency repetition, M signals are synthesized in phase for every N / D samples, thus increasing the peak value, and other time samples become zero or sidelobes. Furthermore, N is an integer greater than 2. Thus, by applying frequency repetition, compared with OFDM signals without frequency repetition, the frequency of peak generation and the magnitude of peak values ​​in the time waveform increase, leading to a problem of reduced transmission power efficiency.

[0035] Next, in the communication system 1 that applies the frequency repetition of this embodiment, the processing of the transmission phase rotation unit 114 included in the transmission baseband processing unit 110 of the transmission device 10, which is a feature of this embodiment, will be described. Figure 5 This is a diagram illustrating an example of the signal waveform of the subcarrier signal sequence obtained by the transmitting device 10 of the communication system 1 in Embodiment 1, and the signal waveform of the time signal block after IDFT transformation. Figure 4 Similarly, in Figure 5 In the image, the left side shows the signal waveform of the subcarrier signal sequence, and the right side shows the signal waveform of the time signal block after IDFT transformation. Figure 5 The signal waveform of the subcarrier signal sequence on the left shows an example of copying a subcarrier signal sequence of length L into 3 copies with equal subcarrier intervals D, assuming the number of copies M=3.

[0036] Copy mapping in subcarrier mapping unit 113 and Figure 4 The example of frequency repetition shown is the same, but in this embodiment, the phase rotation unit 114 transmits the copied mapped subcarrier signal sequence in the subcarrier mapping unit 113, dividing the subcarrier signal sequence of length L into K subsets. Furthermore, K is an integer 2 ≤ K ≤ L. Figure 5 The example shown is one where the number of subsets K=3. Figure 5In the example, each subset is represented as a single signal block with continuous frequency, but it is not limited to this. Each subset can also be multiple dispersed subcarrier signals. In addition, the number of subcarrier signals contained in each subset can be the same or different. Here, when the signal S(f) mapped to the subcarrier f with frequency f belongs to subset #k, the signal S′(f) after phase rotation processing in the phase rotation unit 114 is represented by the following equation (1). Furthermore, the range of k is k 0, ..., K-1.

[0037] [Mathematical Expression 1]

[0038] In equation (1), Φ k It is the phase offset of subset #k. The processing based on equation (1) means that it is allowed to form in-phase synthesis for each subset, and the timing of the time peak is phase-rotated in a different way for each subset. Thus, the transmission phase rotation unit 114 can distribute the timing of in-phase synthesis equally for each subset. In this way, if the number of subcarrier signal sequences copied by the subcarrier mapping unit 113 is M, the subcarrier interval is D, the number of divided subsets is K, and the signal S(f) mapped to the subcarrier f with frequency f belongs to subset #k, the transmission phase rotation unit 114 performs phase rotation processing on the signal S(f) as expressed by equation (1) and outputs the signal S′(f).

[0039] Next, in the communication system 1 that applies the frequency repetition of this embodiment, the processing of the receiving phase rotation unit 214 included in the receiving baseband processing unit 210 of the receiving device 20, which is a feature of this embodiment, will be described. The receiving phase rotation unit 214 compensates for the phase rotation in the transmitting phase rotation unit 114 included in the transmitting baseband processing unit 110 of the transmitting device 10, and performs processing to restore the phase-rotated signal to the state before the phase rotation. That is, the receiving phase rotation unit 214 performs a phase rotation opposite to the phase rotation in equation (1). When the received signal R(f) of the subcarrier f, which is the output of the DFT unit 215, belongs to the subset #k, the receiving phase rotation unit 214 performs the phase rotation processing represented by the following equation (2) to obtain the signal R′(f) that becomes the output signal.

[0040] [Mathematical Expression 2]

[0041] Thus, if the number of subcarrier signal sequences copied by the transmitting device 10 is M, the subcarrier interval when the subcarrier signal sequences copied by the transmitting device 10 are mapped with equal subcarrier intervals is D, and the number of subsets contained in one subcarrier signal sequence when the transmitting device 10 divides each subcarrier signal sequence into subsets is K, and the received signal R(f) of the subcarrier f with frequency f belongs to subset #k, the receiving phase rotation unit 214 performs phase rotation processing on the received signal R(f) as expressed by equation (2) and outputs signal R′(f).

[0042] Figure 6 This is a diagram illustrating an example of the complementary cumulative distribution function characteristics of the instantaneous normalized signal power obtained by the communication system 1 in Implementation 1. Figure 6 To illustrate the effect of phase rotation in the communication system 1 of this embodiment, the complementary cumulative distribution function (CCDF) of the instantaneous normalized signal power transmitted by the transmitting device 10 is obtained through computer simulation. In the computer simulation, the IDFT point number N = 256, the subcarrier signal sequence length L = 56, the subcarrier signal sequence replication number M = 4, and the frequency repetition of the replicated subcarrier signal sequence with subcarrier spacing D = 64 is set. In addition, the subset division number K = 7, and the phase rotation state given by equation (1) is assumed. In addition, the modulation method is QPSK (Quadrature Phase Shift Keying).

[0043] exist Figure 6 In the middle, set CCDF=10 -3 The power value in the equation is defined as PAPR. Assuming QPSK is single modulation, the transmit signal waveform of typical OFDM communication without frequency repetition is confirmed to have PAPR = 8.1 dB. When frequency repetition is applied, the in-phase synthesis of M = 4 copies of the subcarrier signal sequence occurs, thus deteriorating to PAPR = 12.6 dB. In contrast, when frequency repetition is applied as in this embodiment, and phase rotation of each subset is applied, a PAPR equivalent to typical OFDM communication of 8.1 dB can be confirmed. That is, by applying frequency repetition and phase rotation of each subset as in this embodiment, PAPR can be improved by 4.5 dB compared to the case where only frequency repetition is applied. As described above, this is due to the phenomenon of allowing the time signal to be synthesized in phase for each subset, and the effect of performing phase rotation in the frequency domain to make the timing of the time peak different for each subset.

[0044] Furthermore, as an operation of communication system 1, the operation of receiving device 20 occurs after the operation of transmitting device 10. Therefore, a description based on the flowchart is omitted, but the operation of communication system 1 can be understood by... Figure 2 After the operation of the transmitting device 10 shown in the flowchart, Figure 3 The operation of the receiving device 20, as shown in the flowchart, will be explained.

[0045] Next, the hardware structure of the transmitting device 10 will be described. In the transmitting device 10, the transmitting RF unit 120 is a general RF module circuit. The transmitting antenna 130 is an antenna element. The transmitting baseband processing unit 110 is implemented by a processing circuit. The processing circuit can be a processor and memory that execute programs stored in memory, or it can be dedicated hardware. The processing circuit is also referred to as a control circuit.

[0046] Figure 7 This is a diagram illustrating an example of the structure of a processing circuit 90 in which a processor 91 and a memory 92 constitute the processing circuit for implementing the transmitting device 10 of Embodiment 1. Figure 7 The processing circuit 90 shown is a control circuit, comprising a processor 91 and a memory 92. When the processing circuit 90 is composed of the processor 91 and the memory 92, its functions are implemented through software, firmware, or a combination of both. The software or firmware is described as a program and stored in the memory 92. In the processing circuit 90, the processor 91 reads and executes the program stored in the memory 92 to implement each function. That is, the processing circuit 90 has a memory 92 for storing a program that executes the processing of the transmitting device 10. This program can also be described as a program for causing the transmitting device 10 to perform the functions implemented by the processing circuit 90. This program can be provided by a storage medium storing the program, or by other means such as a communication medium.

[0047] The above procedure can also be described as a procedure that causes the transmitting device 10 to perform the following steps: a subcarrier mapping step, in which the subcarrier mapping unit 113 copies the subcarrier signal sequence and maps the copied multiple subcarrier signal sequences with equal subcarrier intervals D; and a transmission phase rotation step, in which the transmission phase rotation unit 114 divides each subcarrier signal sequence mapped with subcarrier intervals D into two or more subsets and assigns a phase rotation to each subset so that each subset is timed differently.

[0048] Here, processor 91 is, for example, a CPU (Central Processing Unit), processing device, arithmetic device, microprocessor, microcomputer, or DSP (Digital Signal Processor). Additionally, memory 92 is, for example, non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read-Only Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable Memory), magnetic disks, floppy disks, optical disks, compact disks, mini-disks, or DVDs (Digital Versatile Discs).

[0049] Figure 8 This is a diagram illustrating an example of a processing circuit 93 in the case where the processing circuit of the transmitting device 10 of Embodiment 1 is implemented by dedicated hardware. Figure 8 The processing circuit 93 shown is, for example, equivalent to a single circuit, a composite circuit, a programmable processor, a parallel programmable processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The processing circuit may also be implemented partly in dedicated hardware and partly in software or firmware. In this way, the processing circuit can achieve the aforementioned functions through dedicated hardware, software, firmware, or a combination thereof.

[0050] The hardware structure of the transmitting device 10 has been described, but the hardware structure of the receiving device 20 is the same. In the receiving device 20, the receiving RF unit 220 is a general RF module circuit. The receiving antenna 230 is an antenna element. The receiving baseband processing unit 210 is implemented by a processing circuit. The processing circuit can be a processor and memory that execute programs stored in memory, or it can be dedicated hardware. The processing circuit is also called a control circuit.

[0051] As explained above, according to this embodiment, in the communication system 1, the transmission phase rotation unit 114 of the transmitting device 10 divides each subcarrier signal sequence mapped by subcarrier interval D into two or more subsets, and applies a phase rotation to each subset to make each subset have a different timing. Specifically, when applying frequency repetition where a subcarrier signal sequence of length L is copied into M copies and mapped at equal intervals by subcarrier interval D, the transmission phase rotation unit 114 divides the subcarrier signal sequence into K subsets, applies a phase rotation to each subset to make each subset have a different timing, so that the timing between subsets is evenly distributed. The receiving phase rotation unit 214 of the receiving device 20 compensates for the phase rotation in the transmitting device 10 by reversing the phase of the received subcarrier signal sequence by the amount of phase rotation applied by the transmission phase rotation unit 114 of the transmitting device 10. As a result, when frequency repetition is applied to OFDM communication, the communication system 1 can suppress the deterioration of the peak-to-average power ratio of the transmitted waveform and suppress the reduction of transmission power efficiency.

[0052] Implementation method 2.

[0053] In Embodiment 1, the case where the transmitting device 10 and the receiving device 20 communicate wirelessly was described. In Embodiment 2, the case where the transmitting device and the receiving device communicate via wired connection was described.

[0054] Figure 9 This is a diagram illustrating a structural example of the communication system 1a according to Embodiment 2. The communication system 1a includes a transmitting device 10a and a receiving device 20a. The communication system 1a enables wired communication between the transmitting device 10a and the receiving device 20a via OFDM communication using frequency repetition. Figure 9 In the example, there is a system based on optical fiber communication. Furthermore, Figure 9 The example shown is a communication system 1a having one transmitting device 10a and one receiving device 20a, but it is not limited thereto. The communication system 1a may also have multiple transmitting devices 10a and multiple receiving devices 20a.

[0055] The transmitting device 10a includes a transmitting baseband processing unit 110 and an E / O (Electrical-to-Optical) unit 140 for electro-optical conversion. The processing content of the transmitting baseband processing unit 110 in Embodiment 2 is the same as that of the transmitting baseband processing unit 110 described in Embodiment 1. The E / O unit 140 converts the baseband signal generated by the transmitting baseband processing unit 110 from an electrical signal to an optical signal and outputs it to the transmission path (in...). Figure 9 In the example, optical fiber.

[0056] The receiving device 20a includes an O / E (Optical-to-Electrical) unit 240 for photoelectric conversion and a receiving baseband processing unit 210. The O / E unit 240 transfers data from the transmission path (in...) Figure 9 In the example, the received signal obtained by the optical fiber is converted from an optical signal into an electrical signal and output to the receiving baseband processing unit 210. The processing content of the receiving baseband processing unit 210 in Embodiment 2 is the same as that of the receiving baseband processing unit 210 described in Embodiment 1.

[0057] Communication system 1a in Figure 9 When the structure shown is used for wired communication, the same effect as the communication system 1 in embodiment 1 can be obtained.

[0058] The structure shown in the above embodiments is an example that can be combined with other known technologies, and the embodiments can be combined with each other. Furthermore, a part of the structure can be omitted or modified without departing from the spirit of the subject.

[0059] Label Explanation

[0060] 1, 1a: Communication system; 10, 10a: Transmitting device; 20, 20a: Receiving device; 90, 93: Processing circuit; 91: Processor; 92: Memory; 110: Transmitting baseband processing unit; 111: Encoding unit; 112: Primary modulation unit; 113: Subcarrier mapping unit; 114: Transmitting phase rotation unit; 115: IDFT unit; 116: GI addition unit; 117: Transmitting waveform shaping unit; 118: DAC 120: Transmit RF section; 130: Transmit antenna; 140: E / O section; 210: Receive baseband processing section; 211: Decoding section; 212: Primary demodulation section; 213: Subcarrier demapping section; 214: Receive phase rotation section; 215: DFT section; 216: GI removal section; 217: Receive waveform shaping section; 218: ADC section; 220: Receive RF section; 230: Receive antenna; 240: O / E section.

Claims

1. A transmitting device for performing orthogonal frequency division multiplexing communication, characterized in that, The transmitting device has the following features: A subcarrier mapping unit that replicates a subcarrier signal sequence and maps the replicated subcarrier signal sequences at equal subcarrier intervals; and A phase rotation unit is transmitted, which divides each subcarrier signal sequence mapped by the subcarrier interval into two or more subsets, and assigns a phase rotation to each subset so that each subset is timed differently.

2. The transmitting device according to claim 1, characterized in that, Let M and D be integers greater than or equal to 1, let K be an integer greater than or equal to 2, and let the range of k be k. 0, ..., K-1, Let M be the number of subcarrier signal sequences copied by the subcarrier mapping unit, D be the subcarrier interval, K be the number of subsets, and S(f) mapped to subcarrier f at frequency f belong to subset #k. If Φ k If the phase shift is for subset #k, then the transmitting phase rotation unit performs phase rotation processing on the signal S(f) as expressed by the following formula and outputs signal S′(f). [Mathematical Expression 1] 。 3. A receiving apparatus for receiving a sequence of subcarrier signals transmitted from a transmitting apparatus performing orthogonal frequency division multiplexing communication, characterized in that, The receiving device has: A receiving phase rotation unit compensates for phase rotation in the transmitting device by inverting the phase of the received subcarrier signal sequence by the amount of phase rotation imparted by the transmitting device; and The subcarrier demapping unit synthesizes the subcarrier signal sequence after the phase rotation is compensated by the receiving phase rotation unit and extracts it as a demodulated signal.

4. The receiving device according to claim 3, characterized in that, Let M and D be integers greater than or equal to 1, let K be an integer greater than or equal to 2, and let the range of k be k. 0, ..., K-1, Let M be the number of subcarrier signal sequences copied by the transmitting device, D be the subcarrier interval when the subcarrier signal sequences copied by the transmitting device are mapped with equally spaced subcarrier intervals, and K be the number of subsets contained in a single subcarrier signal sequence when the transmitting device divides each subcarrier signal sequence into subsets. If the received signal R(f) of subcarrier f with frequency f belongs to subset #k, then... k If the phase shift is for subset #k, the receiving phase rotation unit performs phase rotation processing on the received signal R(f) as expressed by the following formula and outputs signal R′(f). [Mathematical Expression 2] 。 5. A communication system comprising a transmitting device and a receiving device for performing orthogonal frequency division multiplexing communication, characterized in that, The transmitting device includes: A subcarrier mapping unit that replicates a subcarrier signal sequence and maps the replicated subcarrier signal sequences at equal subcarrier intervals; and A phase rotation unit is transmitted, which divides the subcarrier signal sequence mapped by the subcarrier interval into two or more subsets, and assigns a phase rotation to each subset so that each subset is timed differently. The receiving device includes: A receiving phase rotation unit compensates for phase rotation in the transmitting device by inverting the phase of the received subcarrier signal sequence by the amount of phase rotation imparted by the transmitting device; and The subcarrier demapping unit synthesizes the subcarrier signal sequence after the phase rotation is compensated by the receiving phase rotation unit and extracts it as a demodulated signal.

6. The communication system according to claim 5, characterized in that, Let M and D be integers greater than or equal to 1, let K be an integer greater than or equal to 2, and let the range of k be k. 0, ..., K-1, Let M be the number of subcarrier signal sequences copied by the subcarrier mapping unit, D be the subcarrier interval, K be the number of subsets, and S(f) mapped to subcarrier f at frequency f belong to subset #k. If Φ k If the phase shift is for subset #k, then the transmitting phase rotation unit performs phase rotation processing on the signal S(f) as expressed by the following formula and outputs signal S′(f). [Mathematical Expression 3] 。 7. The communication system according to claim 5 or 6, characterized in that, Let M and D be integers greater than or equal to 1, let K be an integer greater than or equal to 2, and let the range of k be k. 0, ..., K-1, Let M be the number of subcarrier signal sequences copied by the transmitting device, D be the subcarrier interval when the subcarrier signal sequences copied by the transmitting device are mapped with equally spaced subcarrier intervals, and K be the number of subsets contained in a single subcarrier signal sequence when the transmitting device divides each subcarrier signal sequence into subsets. If the received signal R(f) of subcarrier f with frequency f belongs to subset #k, then... k If the phase shift is for subset #k, the receiving phase rotation unit performs phase rotation processing on the received signal R(f) as expressed by the following formula and outputs signal R′(f). 【Mathematical Expression 4】 。 8. A control circuit for controlling a transmitting device performing orthogonal frequency division multiplexing communication, characterized in that, The control circuit causes the transmitting device to perform the following processing: The subcarrier signal sequence is copied, and the multiple copied subcarrier signal sequences are mapped at equally spaced subcarrier intervals. The subcarrier signal sequences mapped by the subcarrier interval are divided into two or more subsets, and each subset is given a phase rotation that makes each subset have a different timing.

9. A control circuit for a receiving device that receives a sequence of subcarrier signals transmitted from a transmitting device performing orthogonal frequency division multiplexing communication, characterized in that, The control circuit causes the receiving device to perform the following processing: The phase rotation in the transmitting device is compensated by inverting the phase of the received subcarrier signal sequence by the amount of phase rotation imparted by the transmitting device. The subcarrier signal sequence after phase rotation compensation is synthesized and extracted as a demodulated signal.

10. A control circuit for controlling a communication system comprising a transmitting device and a receiving device for orthogonal frequency division multiplexing communication, characterized in that, The control circuit causes the communication system to perform the following processing: The subcarrier signal sequence is copied, and the multiple copied subcarrier signal sequences are mapped at equally spaced subcarrier intervals. The subcarrier signal sequences mapped by the subcarrier interval are divided into two or more subsets, and each subset is assigned a phase rotation that makes each subset have a different timing. The phase rotation is compensated by the amount of phase rotation imparted by the phase inversion rotation of the received subcarrier signal sequence. The subcarrier signal sequence after phase rotation compensation is synthesized and extracted as a demodulated signal.

11. A storage medium storing a program for controlling a transmitting device performing orthogonal frequency division multiplexing communication, characterized in that, The program causes the transmitting device to perform the following processing: The subcarrier signal sequence is copied, and the multiple copied subcarrier signal sequences are mapped at equally spaced subcarrier intervals. The subcarrier signal sequences mapped by the subcarrier interval are divided into two or more subsets, and each subset is given a phase rotation that makes each subset have a different timing.

12. A storage medium storing a program for controlling a receiving device that receives a sequence of subcarrier signals transmitted from a transmitting device performing orthogonal frequency division multiplexing communication, characterized in that, The procedure causes the receiving device to perform the following processing: The phase rotation in the transmitting device is compensated by inverting the phase of the received subcarrier signal sequence by the amount of phase rotation imparted by the transmitting device. The subcarrier signal sequence after phase rotation compensation is synthesized and extracted as a demodulated signal.

13. A storage medium storing a program for controlling a communication system, the communication system comprising a transmitting device and a receiving device for performing orthogonal frequency division multiplexing communication, characterized in that... The program causes the communication system to perform the following processing: The subcarrier signal sequence is copied, and the multiple copied subcarrier signal sequences are mapped at equally spaced subcarrier intervals. The subcarrier signal sequences mapped by the subcarrier interval are divided into two or more subsets, and each subset is assigned a phase rotation that makes each subset have a different timing. The phase rotation is compensated by the amount of phase rotation imparted by the phase inversion rotation of the received subcarrier signal sequence. The subcarrier signal sequence after phase rotation compensation is synthesized and extracted as a demodulated signal.

14. A transmission method of a transmitting device, the transmitting device performing orthogonal frequency division multiplexing communication, characterized in that, The sending method includes: The subcarrier mapping step involves a subcarrier mapping unit copying a subcarrier signal sequence and mapping the copied subcarrier signal sequences at equal subcarrier intervals; and In the phase rotation step, the phase rotation unit divides the subcarrier signal sequence mapped by the subcarrier interval into two or more subsets, and assigns a phase rotation to each subset so that each subset is timed differently.

15. A receiving method of a receiving apparatus, the receiving apparatus receiving a sequence of subcarrier signals transmitted from a transmitting apparatus performing orthogonal frequency division multiplexing communication, characterized in that, The receiving method includes: The receiving phase rotation step involves the receiving phase rotation unit inverting the phase of the received subcarrier signal sequence by the amount of phase rotation imparted by the transmitting device, thereby compensating for the phase rotation in the transmitting device. as well as In the subcarrier demapping step, the subcarrier demapping unit synthesizes the subcarrier signal sequence after the phase rotation is compensated by the receiving phase rotation unit and extracts it as a demodulated signal.

16. A signal processing method for a communication system, the communication system comprising a transmitting device and a receiving device for orthogonal frequency division multiplexing communication, characterized in that, The signal processing method includes: In the subcarrier mapping step, the subcarrier mapping unit of the transmitting device copies the subcarrier signal sequence and maps the copied multiple subcarrier signal sequences at equal subcarrier intervals. In the phase rotation step, the phase rotation unit of the transmitting device divides each subcarrier signal sequence mapped by the subcarrier interval into two or more subsets, and assigns a phase rotation to each subset so that each subset is timed differently. In the receiving phase rotation step, the receiving phase rotation unit of the receiving device compensates for the phase rotation in the transmitting device by inverting the phase of the received subcarrier signal sequence by the amount of phase rotation given by the transmitting device. as well as In the subcarrier demapping step, the subcarrier demapping unit of the receiving device synthesizes the subcarrier signal sequence after the phase rotation is compensated by the receiving phase rotation unit and extracts it as a demodulated signal.

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