JP2009077302A - COMMUNICATION DEVICE, ITS CONTROL METHOD, COMMUNICATION SYSTEM - Google Patents

Abstract

A communication apparatus that performs communication using a plurality of subcarriers and realizes stable communication with few errors.
In a communication apparatus that communicates using a plurality of subcarriers, the same allocation unit that allocates two or more subcarriers for transmitting the same data from a plurality of subcarriers is the same by the allocated subcarriers. Transmitting means for transmitting the data, acquiring means for acquiring information from the external device receiving the transmitted data, or information regarding the noise status of the frequency band to be used, and the assigning means based on the result of information acquisition And a control means for controlling to change the subcarrier allocation according to.
[Selection] Figure 2

Description

  The present invention relates to a communication technique for performing communication using a plurality of carrier waves.

In recent years, in the communication field, communication systems using orthogonal frequency division multiplexing (OFDM) have attracted attention because of the necessity of large-capacity communication and anti-multipath characteristics. Particularly in the field of wireless communication, the wireless LAN is used for IEEE 802.11a / g standard and terrestrial digital television broadcasting. Alternatively, it is also used in WiMedia multiband OFDM (ECMA-368; Non-Patent Document 1), which is one of UWB (Ultra Wideband) communications. In particular, in OFDM communication, even if fading due to multipath occurs, channel correction is possible on the receiving side, so that there is an advantage that the influence on communication can be reduced.
ECMA-368 High Rate Ultra Wideband PHY and MAC Standard, Ecma International, 2005

  However, in wireless communication based on the ECMA-368 standard, when a frequency band near the center frequency is subjected to multipath fading, a plurality of subcarriers transmitting the same data are simultaneously affected. Therefore, there is a problem that the error rate becomes high when the frequency band near the center frequency is fading. In addition, when other communication is detected, there is a function called DAA (Detect and Avoidance) for performing communication in which transmission of subcarriers in the band is suppressed. When other communications are detected in the vicinity of the center frequency, there is a problem that the probability of occurrence of an error increases when a plurality of subcarriers transmitting the same data are simultaneously suppressed by this DAA function.

  In order to solve the above-described problems, the communication apparatus of the present invention has the following configuration. That is, a communication apparatus that performs communication using a plurality of subcarriers, the allocating unit allocating two or more subcarriers for transmitting the same data from the plurality of subcarriers, and the allocating unit Transmitting means for transmitting the same data by subcarriers, information relating to reception from an external device receiving data transmitted by the transmitting means, or obtaining means for acquiring information relating to noise conditions in the frequency band to be used, Control means for controlling to change the allocation of subcarriers by the allocation means based on the result of information acquisition by the acquisition means.

  In order to solve the above-described problems, the communication apparatus control method of the present invention has the following configuration. That is, a method for controlling a communication apparatus that performs communication using a plurality of subcarriers, the allocation step of allocating two or more subcarriers for transmitting the same data from the plurality of subcarriers, and the allocation step A transmission step of transmitting the same data by subcarriers assigned by the method, and an acquisition step of acquiring information related to reception from an external device that receives the data transmitted in the transmission step, or information relating to a noise status of a frequency band to be used And a control step of controlling to change the subcarrier allocation in the allocation step based on the information acquisition result in the acquisition step.

  In order to solve the above-described problems, the communication system of the present invention has the following configuration. That is, a communication system including a transmission device and a reception device that performs communication using a plurality of subcarriers, wherein the transmission device includes two or more subcarriers for transmitting data from the plurality of subcarriers. Information relating to reception from a receiving device that receives data transmitted by an allocating unit for allocating a carrier, data transmitted by subcarriers allocated by the allocating unit, and data transmitted by the transmitting unit, or noise status of a frequency band to be used Acquisition means for acquiring information related to, and control means for controlling the allocation of subcarriers by the allocation means based on a result of information acquisition by the acquisition means, wherein the reception device is Based on receiving means for receiving a plurality of subcarriers to be transmitted and information obtained by the received subcarriers. Determining means for determining subcarriers that receive the same data; data receiving means for receiving data transmitted on the determined subcarriers; and information related to reception based on a data reception state in the receiving means. Receiving information transmitting means for transmitting to the transmitting device.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which can perform multicarrier communication stably can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are merely examples, and are not intended to limit the scope of the present invention.

(First embodiment)
As a first embodiment of a communication system according to the present invention, a wireless communication system including a transmission device and a reception device compliant with the ECMA-368 standard will be described below as an example. As a communication method, orthogonal frequency division multiplexing (OFDM) is used.

<Device configuration>
FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to the first embodiment. Reference numeral 10 denotes a transmitting device, and 20 denotes a receiving device. For convenience, the transmission device 10 and the reception device 20 are separated, but the transmission device 10 includes a reception unit corresponding to the reception device 20. The reception device 20 also has a transmission unit corresponding to the transmission device 10.

・ Transmitter 10
Reference numeral 101 denotes an encoding unit that performs convolutional encoding and puncturing of data to be transmitted. An interleaver 102 performs an interleaving process on the data encoded by the encoding unit 101. Reference numeral 103 denotes a serial-parallel (S / P) conversion unit that converts data interleaved by the interleaver 102 into parallel data. A mapper 104 assigns (maps) the data converted into parallel data by the S / P converter to a plurality (two or more) of subcarriers. Specifically, processing of FDS, TDS, and DCM described later is performed, and the same data is mapped to a plurality of subcarriers.

  A subcarrier arrangement setting unit 105 sets the arrangement of subcarriers for data to be transmitted. Specifically, in addition to the subcarrier arrangement mapped by the mapper 104, the subcarrier arrangement is set based on a subcarrier arrangement change request from the receiving apparatus 20 described later. A pilot generation unit 106 generates data to be transmitted as a pilot signal.

  Reference numeral 107 denotes an IFFT unit, which combines data input from the subcarrier arrangement setting unit 105 and the pilot generation unit 106, data for dummy subcarriers not shown, and zero (null) subcarriers to generate an IFFT. (Inverse FFT) processing is performed. In the ECMA-368 standard, 128-point IFFT processing is performed.

  Reference numeral 108 denotes a PF / GI adding unit that adds a zero prefix and a no-signal period of a guard interval for each symbol to data converted into time domain data by the IFFT unit 107. Although not shown, a preamble is added for each packet to generate a baseband signal. The frequency converter 109 converts the frequency of the baseband signal according to a preset channel. In particular, when a TFC (Time-Frequency Code) parameter for designating a frequency conversion pattern is “1” or “2”, frequency hopping is performed for each symbol. On the other hand, when the TFC parameter is “3” or “4”, frequency hopping is performed every two symbols. The frequency-converted signal is transmitted via the antenna 110.

  Although not shown in the figure, a receiving unit for receiving a signal from the receiving device 20 is further provided. Although details will be described later, the receiving unit receives information related to reception of data transmitted by the transmission device 10 at the reception device 20 (reception information acquisition unit).

・ Receiver 20
Reference numeral 210 denotes an antenna which receives a signal transmitted from the antenna 110 of the transmission apparatus 10. A frequency conversion unit 209 performs channel estimation based on a received signal preamble pattern, and performs frequency conversion corresponding to the estimated TFC parameter of the channel. A baseband signal is then generated. Reference numeral 208 denotes a PF / GI removing unit that removes the zero prefix and the guard interval from the baseband signal.

  Reference numeral 207 denotes an FFT unit that performs FFT processing on the data input from the PF / GI removal unit 208. In the ECMA-368 standard, 128-point FFT processing is performed. Thereafter, the pilot removal unit 206 removes the pilot signal. Further, data corresponding to dummy subcarriers not shown and zero subcarriers are removed.

  Reference numeral 205 denotes a subcarrier arrangement setting unit, which sets to which subcarrier each of data input from the FFT unit 207 corresponds. For example, a subcarrier rearrangement request (to be described later) is applied to data received after transmission, and is set to the subcarrier arrangement instructed to the transmission side. That is, the subcarrier arrangement corresponding to the setting of the subcarrier arrangement setting unit 105 in the transmission apparatus 10 is set.

  A demapper 204 restores the data mapped to each subcarrier. That is, the same data transmitted by a plurality of subcarriers by FDS, TDS or DCM is synthesized. A parallel-serial (P / S) conversion unit 203 converts data input from the demapper 204 into serial data. Reference numeral 202 denotes a deinterleaver that restores the data interleaved by the transmission apparatus 10. The Viterbi decoding unit 201 decodes the encoded data.

  Although not shown in the figure, a transmission unit for transmitting a signal to the transmission device 10 is further provided. Although details will be described later, the transmission unit transmits information related to reception of data transmitted by the transmission device 10 at the reception device 20 (reception information transmission means).

<Data transmission operation>
As described above, ECMA-368 is configured to transmit the same data a plurality of times. In other words, the stability of communication is improved by providing redundancy to the data to be transmitted. As specific methods, FDS (Frequency Domain Spreading), TDS (Time Domain Spreading), and DCM (Dual Carrier Modulation) are defined. The same data is transmitted twice at different frequencies and times. Or it transmits 4 times combining both FDS and TDS.

  7 to 9 are conceptual diagrams of data transmission by FDS, TDS, and DCM, respectively. In each of FIGS. 7 to 9, subcarriers connected by arrows shown at the bottom of the drawings transmit the same data. A subcarrier number surrounded by a square indicates a pilot subcarrier.

  As shown in FIG. 7, in FDS, subcarriers that transmit the same data are complex conjugate signals. On the other hand, as shown in FIG. 8, in TDS, the arrangement of primary modulation signal points is set to be different. Note that the code calculation is performed between the first symbol and the second symbol composed of the same data, but is omitted in the figure for the sake of simplicity. Further, as shown in FIG. 9, in DCM, the arrangement of the primary modulation signal points is set differently as in TDS.

  By the way, in the ECMA-368 standard, the frequency hopping pattern differs depending on the communication channel. In addition, when the data rate is different, the arrangement method for transmitting the same data is different.

  If the channel does not perform frequency channel hopping (TFC 5 to 7) and the transmission rate is 53.3 to 200 Mbps, it is the same for subcarriers separated by the same frequency from the center frequency to the high frequency side / low frequency side. It is configured to transmit the data.

  FIG. 2 is a diagram schematically illustrating a reception spectrum of a signal that has undergone multipath fading. Here, a state is shown in which multipath fading is received in the vicinity of the center frequency (portion where the subcarrier number is small). In the figure, the vertical axis represents the received intensity, and the horizontal axis represents the frequency.

  As described in the description of the transmitting apparatus 10, in the ECMA-368 standard, 128-point IFFT is performed at the time of modulation by OFDM. Of these, 6 are not used as zero subcarriers. Therefore, there are 122 subcarrier frequency positions in total.

61 subcarriers are arranged on both sides of the zero subcarrier at the position of the center frequency. The subcarrier interval is 4.125 MHz. In the following, a total of 122 subcarrier numbers (frequency positions of subcarriers) of 122 (= 61 × 2) are sequentially ordered from the lowest frequency,
# -61, # -60,. . . , # -2, # -1, # + 1, # + 2,. . . , # + 60, # + 61
A number will be described as follows.

  Here, the subcarriers of # ± 5, # ± 15, # ± 25,... # ± 55 are pilots. Each pilot subcarrier is equally arranged in a plurality of subcarriers in order to adjust a phase shift of signal points due to a frequency shift between transmitting and receiving apparatuses. Data is transmitted on subcarriers from # ± 1 to 56. The subcarriers of # ± 57 to 61 are dummy data for copying the subcarriers of # ± 52 to 56. Note that subcarriers are not arranged in the center frequency portion (between # -1 and # + 1).

  FIG. 2A is a diagram showing the relationship between subcarrier arrangement and signal attenuation due to fading when FDS is used. As described above, in FDS, subcarriers equidistant from the center frequency transmit complex conjugate data. Therefore, as is apparent from the figure, the same two data arranged on subcarrier # ± 1 are both greatly affected by fading. For this reason, both of the data transmitted on each subcarrier are likely to cause errors.

  Therefore, in the first embodiment, the receiving apparatus 20 transmits a subcarrier rearrangement request to the transmitting apparatus 10. Specifically, as shown in FIG. 2B, the order of subcarriers # + 1 to 56 is changed. With such an arrangement, at least one of the same data transmitted on two subcarriers can be made less susceptible to fading.

  For example, the same two data originally transmitted on the subcarriers of # ± 1 are transmitted on the subcarriers of # + 1 and # -56. Therefore, the data transmitted in # -56 can avoid the influence of fading.

  In the example of FIG. 2B, only the data subcarriers from subcarriers # + 1 to # + 61 are rearranged. Therefore, the frequency difference between subcarriers transmitting the same data is shifted by one subcarrier before and after the pilot subcarrier.

  However, when the total number of subcarriers (122 in this case) is large, the frequency difference of each subcarrier transmitting the same data is substantially equal. For this reason, fading resistance substantially equivalent to that when the frequency difference of each subcarrier transmitting the same data is completely equal can be obtained.

  Although the case of FDS has been described here, reception errors due to fading can be reduced similarly in the case of TDS.

  In wideband communication such as UWB, a plurality of fadings may be observed in the communication band. In this case, even if DCM is used, both subcarriers that transmit the same data may be affected by fading. Even in such a case, the method of the present invention for changing the subcarrier arrangement at the time of retransmission is effective.

<Data transmission operation flow>
FIG. 3 is an operation flowchart in the wireless communication system according to the first embodiment. It is assumed that data is transmitted with the subcarrier arrangement of FIG. 2A at the start of data transmission (initial state). That is, the transmitting apparatus 10 controls and sets the subcarrier arrangement setting unit 105 so that the subcarrier arrangement shown in FIG. In addition, the receiving device 20 controls and sets the subcarrier arrangement setting unit 205 to receive data with the subcarrier arrangement of FIG.

  In step S301, the transmission device 10 transmits data to the reception device 20 with the set subcarrier arrangement.

  In step S302, the receiving device 20 decodes the signal received from the transmitting device 10 with the set subcarrier arrangement. If the data can be normally received (decoded), the process proceeds to step S303. On the other hand, if the data cannot be received normally, the process proceeds to step S304.

  In step S <b> 303, the reception device 20 transmits Ack indicating normal reception to the transmission device 10. On the other hand, in step S304, receiving apparatus 20 transmits a subcarrier rearrangement request signal (arrangement change request signal) to transmitting apparatus 10, and returns to the reception standby state again. At this time, data that explicitly specifies the arrangement of subcarriers may be transmitted together. Further, the signal may not be a signal that explicitly requests subcarrier rearrangement, but may be configured to transmit information about the reception state such as reception error information (reception information generation means). Further, when the error rate is included in the information regarding the reception state, the transmission device 10 may perform subcarrier rearrangement when the error rate exceeds a certain value.

  For example, the reception strength of each subcarrier can be derived by channel estimation using a preamble portion of a data frame transmitted on each subcarrier. Based on the derived reception strength of each subcarrier, the arrangement of subcarriers can be determined by the receiving device 20. Of course, it may be configured to select from an arrangement pattern of subcarriers prepared in advance.

  In step S305, the transmission device 10 determines whether or not Ack is received from the reception device 20. If Ack is received, it is determined that the data transmitted in step S301 has been normally received by the receiving device 20, and the process ends. On the other hand, if a subcarrier relocation request signal is received, the process proceeds to step S306.

  In step S306, the transmission apparatus 10 performs rearrangement of subcarriers and retransmits data.

  Thus, by transmitting data, the possibility that the receiving device 20 cannot receive data during retransmission can be greatly reduced. In the above-described flow, the presence / absence of reception is determined for each data, and the arrangement of subcarriers is changed. However, the arrangement of subcarriers may be changed based on the reception status of a plurality of different data. For example, the arrangement of subcarriers may be changed based on whether or not the error rate exceeds a predetermined threshold value.

  Further, the arrangement of subcarriers is not limited to that shown in FIG. For example, in FIG. 2B, priority is given to the equal arrangement of pilot subcarriers. However, the arrangement may be changed so that the frequency difference (frequency interval) of each subcarrier transmitting the same data is the same for each different data.

  Further, when a reception error occurs, a subcarrier rearrangement request may be made so that the transmission intensity or energy sum of subcarriers transmitting the same data is substantially equal between the data.

  As described above, according to the communication system according to the first embodiment, when information related to reception from the receiving apparatus is acquired or the analysis result of the acquired information is changed, the subcarrier allocation is changed and retransmitted. Therefore, more stable communication can be realized.

(Modification 1)
In the first modification, an example in which the arrangement of subcarriers is changed (updated) led by the transmission apparatus side will be described.

  FIG. 4 is a diagram illustrating a configuration of a wireless communication system according to the first modification. Reference numeral 10 denotes a transmitting device, and 20 denotes a receiving device. The internal configuration of each of the transmission device 10 and the reception device 20 is substantially the same as that of FIG. However, the difference is that subcarrier arrangement estimation setting section 215 of receiving apparatus 20 in Modification 1 further has a function of estimating the arrangement of subcarriers based on the received subcarrier signal.

  In the following description, subcarrier arrangement setting section 105 of transmitting apparatus 10 and subcarrier arrangement estimation setting section 215 of receiving apparatus 20 each store information on arrangements of some preset subcarriers. It shall be. For example, two pieces of arrangement information corresponding to the subcarrier arrangement shown in FIG. 2A and the subcarrier arrangement shown in FIG. 2B are stored.

<Data transmission operation flow>
FIG. 5 is an operation flowchart in the wireless communication system according to the first modification. It is assumed that data is transmitted with the subcarrier arrangement of FIG. 2A at the start of data transmission (initial state). That is, the transmitting apparatus 10 controls and sets the subcarrier arrangement setting unit 105 so that the subcarrier arrangement shown in FIG. In addition, the receiving device 20 controls and sets the subcarrier arrangement estimation setting unit 215 so as to receive data with the subcarrier arrangement of FIG.

  In step S501, the transmission apparatus 10 transmits data to the reception apparatus 20 with the set subcarrier arrangement.

  In step S502, the reception device 20 decodes the signal received from the transmission device 10 with the set subcarrier arrangement. If the data can be normally received (decoded), the process proceeds to step S503. On the other hand, if the data cannot be received normally, it returns to the reception standby state again.

  In step S503, the reception device 20 transmits Ack indicating normal reception to the transmission device 10.

  In step S504, the transmission device 10 determines whether or not an Ack has been received from the reception device 20. If Ack is received, it is determined that the data transmitted in step S301 has been normally received by the receiving device 20, and the process ends. On the other hand, if Ack is not received within a preset time after data transmission (when acquisition is not possible), the process proceeds to step S505.

  In step S505, the transmission apparatus 10 selects one of the subcarrier arrangement patterns prepared in advance, performs subcarrier arrangement, and retransmits data.

  Thus, by transmitting data, the possibility that the receiving device 20 cannot receive data during retransmission can be greatly reduced.

  At the time of data reception, subcarrier arrangement estimation setting section 215 of receiving apparatus 20 estimates the subcarrier arrangement based on the received subcarrier signal. That is, it is determined which carrier arrangement is selected from among some preset subcarrier arrangements. Specifically, it is determined which pattern has been rearranged by taking a correlation between subcarriers.

  In the above flow, it has been described that the presence / absence of Ack reception is determined for each data, and the subcarrier arrangement is changed. However, the arrangement of subcarriers may be changed based on the reception status (reception history) of a plurality of different data. For example, the arrangement of subcarriers may be changed based on whether or not the error rate exceeds a predetermined threshold value.

  As described above, since the subcarrier arrangement is changed based on the information acquisition result from the receiving device that the Ack could not be received, more stable communication can be realized even in the configuration of the first modification. Is possible.

(Modification 2)
In Modification 2, a communication system having a DAA (Detect and Avoidance) function that detects other communication signals and suppresses transmission power of the band will be described.

  FIG. 6 is a diagram illustrating a configuration of a wireless communication system according to the second modification. Reference numeral 10 denotes a transmitting device, and 20 denotes a receiving device. The internal configuration of each of the transmission device 10 and the reception device 20 is substantially the same as that of the first modification, except that the transmission device 10 includes a DAA unit 111.

  DAA section 111 is arranged between subcarrier arrangement setting section 105 and IFFT section 107. And the signal (noise) of the communication of the external apparatus which is not related to this communication system is detected, and the noise situation of the used frequency band is determined (acquired). And when noise exceeds a predetermined value, it controls so that transmission of the subcarrier of a band with a large noise is suppressed.

  Therefore, a subcarrier arrangement is selected such that both the subcarriers that transmit the same data are not included in the frequency band of the signal of the external device detected by the DAA unit 111. It is assumed that subcarrier arrangement setting section 105 of transmitting apparatus 10 and subcarrier arrangement estimation setting section 215 of receiving apparatus 20 each store information on the arrangement of several subcarriers set in advance.

  By adopting such a configuration, the noise situation of the frequency band being used is determined, information on the determination result is obtained, and subcarrier allocation is changed based on this information. In addition, more stable communication can be realized.

(Other embodiments)
The present invention can also be achieved by supplying a program that realizes the functions of the above-described embodiments directly or remotely to a system or apparatus, and the system or apparatus reads and executes the supplied program code. The Accordingly, the program code itself installed in the computer in order to realize the functional processing of the present invention by the computer is also included in the technical scope of the present invention.

  In this case, the program may be in any form as long as it has a program function, such as an object code, a program executed by an interpreter, or script data supplied to the OS.

  Examples of the recording medium for supplying the program include a floppy (registered trademark) disk, a hard disk, an optical disk (CD, DVD), a magneto-optical disk, a magnetic tape, a nonvolatile memory card, and a ROM.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. In addition, based on the instructions of the program, an OS or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can also be realized by the processing.

  Further, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing based on the instructions of the program, and the functions of the above-described embodiments are realized by the processing.

It is a figure which shows the structure of the radio | wireless communications system which concerns on 1st Embodiment. It is the figure which represented typically the reception spectrum of the signal which has received multipath fading. 6 is an operation flowchart in the radio communication system according to the first embodiment. It is a figure which shows the structure of the radio | wireless communications system which concerns on the modification 1. FIG. 10 is an operation flowchart in a wireless communication system according to Modification 1. It is a figure which shows the structure of the radio | wireless communications system which concerns on the modification 2. It is a conceptual diagram of the data transmission by FDS. It is a conceptual diagram of the data transmission by TDS. It is a conceptual diagram of the data transmission by DCM.

Claims (9)

A communication device that communicates using a plurality of subcarriers,
Allocating means for allocating two or more subcarriers for transmitting the same data from the plurality of subcarriers;
Transmitting means for transmitting the same data by subcarriers assigned by the assigning means;
Information relating to reception from an external device that receives data transmitted by the transmission means, or acquisition means for obtaining information relating to the noise status of the frequency band to be used;
Control means for controlling the allocation of subcarriers by the allocation means based on the result of information acquisition by the acquisition means;
A communication apparatus comprising:   2. The communication apparatus according to claim 1, wherein the control unit performs control so as to change subcarrier allocation by the allocation unit based on reception error information regarding the data as information regarding the reception.   2. The communication apparatus according to claim 1, wherein the control unit performs control to change subcarrier allocation by the allocation unit based on a subcarrier arrangement change request as information regarding the reception.   The control means controls the subcarrier allocation by the allocation means to be changed when the acquisition means cannot acquire information related to the reception related to the data after transmission of data by the transmission means. The communication device according to claim 1.   The control means, when judging that the noise of the frequency band to be used exceeds a predetermined value based on the information acquired by the acquisition means, controls to change the subcarrier allocation by the allocation means. Item 4. The communication device according to Item 1.   2. The communication apparatus according to claim 1, wherein the allocating unit allocates the two or more subcarriers transmitting the same data so that frequency intervals of the different data are equal to each other.   The communication apparatus according to claim 1, wherein the communication apparatus is an orthogonal frequency division multiplexing (OFDM) communication apparatus. A method for controlling a communication device that communicates using a plurality of subcarriers,
An allocating step of allocating two or more subcarriers for transmitting the same data from the plurality of subcarriers;
A transmission step of transmitting the same data by subcarriers allocated by the allocation step;
An acquisition step of acquiring information related to reception from an external device that receives data transmitted by the transmission step, or information related to a noise status of a frequency band to be used;
A control step for controlling the allocation of subcarriers in the allocation step based on the result of information acquisition in the acquisition step;
A method for controlling a communication apparatus, comprising: A communication system including a transmission device and a reception device that performs communication using a plurality of subcarriers,
The transmitter is
Allocating means for allocating two or more subcarriers for transmitting data from the plurality of subcarriers;
Transmitting means for transmitting data by subcarriers assigned by the assigning means;
Information relating to reception from a receiving device that receives data transmitted by the transmission means, or acquisition means for obtaining information relating to a noise situation of a frequency band to be used;
Control means for controlling to update the subcarrier allocation by the allocation means based on the result of information acquisition by the acquisition means;
With
The receiving device is:
Receiving means for receiving a plurality of subcarriers transmitted from the transmitting device;
Determining means for determining subcarriers that receive the same data based on information obtained by the received subcarriers;
Data receiving means for receiving data transmitted on the determined subcarrier;
Reception information transmission means for transmitting information related to reception to the transmission device based on a data reception state in the reception means;
Comprising
A communication system characterized by the above.

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