JP2012169954A - Communication system, communication device, communication method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system which can avoid deterioration in transmission quality.SOLUTION: A communication device 1 comprises: a transmission part 11 performing transmission in a plurality of frequency bands by spectrum division single carrier modulation system; a reception part 12; an acquisition part 13 acquiring a plurality of free frequency bands; a control part 14 which makes communication data for acquiring transmission path characteristics be transmitted in the plurality of free frequency bands, and makes transmission in a plurality of frequency bands having good transmission path characteristics when the communication data showing the frequency bands having good transmission path characteristics are received. A communication device 2 comprises: a transmission part 21 performing transmission in a plurality of frequency bands by the spectrum division single carrier modulation system; a reception part 22; a transmission path characteristic acquisition part 23 acquiring a transmission path characteristic according to received communication data for acquiring the transmission path characteristic; a selection part 24 selecting a frequency band having a good transmission path characteristic; and a control part 26 making the selected frequency band be transmitted in the frequency band.

Description

  The present invention relates to a communication system that performs communication using a vacant frequency band.

  Conventionally, in the ISM (Industry-Science-Medical) band or the like, a concept of dynamic spectrum access (DSA) that accumulates fragmented free frequency bands and uses it as one radio channel has been proposed (for example, Non-patent document 1). As a spectrum control method suitable for the DSA, a spectrum division single carrier modulation method has been proposed in which a spectrum of single carrier modulation is divided into a plurality of bands by a bandpass filter, and each frequency is converted and transmitted (for example, Patent Document 1, Non-Patent Document 2).

JP 2010-232857 A

Taro Maruma, Hitoshi Yano, Seiji Tsukamoto, Masazumi Ueha, “Proposal of Dynamic Spectrum Access System for Highly Efficient Frequency Sharing in ISM Band”, IEICE Technical Report, vol. 108, no. 446, SR2008-97, p. 53-57, March 2009 Yasuo Suzuki, Makoto Taro Maru, Hitoshi Yano, Masazumi Kamiha, “Basic performance of spectrum division single carrier transmission system with band limitation for DSA”, IEICE Tech. 109, no. 164, RCS 2009-81, p. 19-23, August 2009

  In the conventional spectrum division single carrier modulation method in DSA, a plurality of vacant frequency bands are used. However, the frequency band may include one having poor transmission path characteristics between communication devices. There was a problem of lowering.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a communication system that performs communication using a spectrum division single carrier modulation method that can prevent a decrease in transmission quality.

  In order to achieve the above object, a communication system according to the present invention is a communication system including a first communication device and a second communication device that communicate with each other using a vacant frequency band, the first communication device. Includes a first transmitter that transmits communication data using a spectrum division single carrier modulation scheme using a plurality of frequency bands, and a first receiver that receives communication data transmitted from the second communication device. An acquisition unit that acquires a plurality of vacant frequency bands, which are frequency bands that are not used for communication, and first transmission of communication data for transmission path characteristic acquisition using the plurality of vacant frequency bands acquired by the acquisition unit Transmitted when the first receiving unit receives communication data indicating a plurality of frequency bands having good transmission path characteristics among a plurality of frequency bands transmitted to the transmission section and transmitting communication data for acquiring transmission path characteristics. A first control unit that causes the first transmission unit to transmit communication data using a plurality of frequency bands having good characteristics, and the second communication device receives the communication data transmitted from the first communication device. A second receiving unit for receiving, a second transmitting unit for transmitting communication data by a spectrum division single carrier modulation method using a plurality of frequency bands, and for acquiring transmission path characteristics received by the second receiving unit. Transmission path characteristics acquisition using a transmission path characteristics acquisition unit that acquires transmission path characteristics of multiple frequency bands used in communication data communication and predetermined conditions for judging the quality of transmission path characteristics A selection unit that selects a plurality of frequency bands that are determined to satisfy the transmission path characteristics acquired by the unit, and a plurality of communication data that indicates the plurality of frequency bands selected by the selection unit. Frequency A second control unit for transmitting the second transmission unit with the band, but with the.

  With such a configuration, communication can be performed using a frequency band with good transmission path characteristics among a plurality of vacant frequency bands. As a result, it is possible to avoid a decrease in transmission quality. In addition, since a frequency band with poor transmission path characteristics is not occupied, radio resources can be used effectively.

In the communication system according to the present invention, the second control unit performs control such that acquisition of the transmission line characteristics by the transmission line characteristic acquisition unit and selection by the selection unit according to the acquisition result are repeatedly performed, The communication apparatus further includes a history information recording unit that records history information that is history information of a selection result by the selection unit, and the second control unit has a change in the selected frequency band indicated by the history information. You may control so that selection is performed more frequently, so that it is quick.
With such a configuration, for example, even when the transmission path characteristics fluctuate frequently, such as when the first communication device is moving, the frequency band used for communication is changed according to the fluctuation. It may be possible to select appropriately.

  Further, the communication method according to the present invention is a communication method for performing communication using an empty frequency band, an acquisition step for acquiring a plurality of empty frequency bands that are not used for communication, and transmission path characteristic acquisition First transmission step of transmitting the communication data for use by the spectrum division single carrier modulation method using the plurality of vacant frequency bands acquired in the acquisition step, and the communication destination device by the spectrum division single carrier modulation method. Further, a receiving step for receiving communication data indicating a plurality of frequency bands having good transmission path characteristics among a plurality of frequency bands for transmitting communication data for acquiring transmission path characteristics, and a transmission path indicated by the communication data received in the receiving step Using multiple frequency bands with good characteristics, communication data can be transmitted by spectrum division single carrier modulation. A second transmitting step of transmitting those equipped with.

  The communication method according to the present invention is a communication method for performing communication using a vacant frequency band, and is characterized by transmission path characteristics transmitted by a spectrum division single carrier modulation method using a plurality of vacant frequency bands from a communication destination device. A reception step for receiving communication data for acquisition, a transmission line characteristic acquisition step for acquiring transmission line characteristics of a plurality of frequency bands used in communication of communication data for transmission line characteristics received in the reception step, and transmission A selection step for selecting a plurality of frequency bands that are determined to be good enough that the transmission path characteristics acquired in the transmission path characteristics acquisition step satisfy the conditions using predetermined conditions for determining whether the path characteristics are good or bad; The communication data indicating the plurality of frequency bands selected in the selection step is transmitted using the plurality of frequency bands selected in the selection step. A transmission step of transmitting to the communication destination device by dividing a single carrier modulation scheme is obtained with a.

  According to the communication system and the like according to the present invention, communication can be performed using a frequency band with good transmission path characteristics among a plurality of vacant frequency bands, and a decrease in transmission quality can be avoided.

The block diagram which shows the structure of the communication system by Embodiment 1 of this invention. The block diagram which shows the structure of the transmission part and receiving part by the embodiment The flowchart which shows operation | movement of the 1st communication apparatus by the embodiment The flowchart which shows operation | movement of the 2nd communication apparatus by the embodiment The figure for demonstrating the specific example of the spectrum division | segmentation in the embodiment Schematic diagram showing an example of the appearance of the computer system in the embodiment The figure which shows an example of a structure of the computer system in the embodiment

  Hereinafter, a communication system according to the present invention will be described using embodiments. In the following embodiments, components and steps denoted by the same reference numerals are the same or equivalent, and repetitive description may be omitted.

(Embodiment 1)
A communication system according to Embodiment 1 of the present invention will be described with reference to the drawings. The communication system according to the present embodiment performs communication using a portion having a good transmission path characteristic among a plurality of vacant communication bands.

  FIG. 1 is a block diagram showing a configuration of a communication system 100 according to the present embodiment. A communication system 100 according to the present embodiment includes a first communication device 1 and a second communication device 2. The first and second communication devices 1 and 2 perform wireless communication via antennas 3 and 4, respectively. For example, one of the first and second communication apparatuses 1 and 2 may be a mobile station (MS) and the other may be an access point (AP). In the present embodiment, the case where the first communication device 1 is an MS and the second communication device 2 is an AP will be mainly described. Needless to say, this need not be the case.

  The first communication device 1 includes a first transmission unit 11, a first reception unit 12, an acquisition unit 13, and a first control unit 14.

  The first transmission unit 11 transmits communication data by a spectrum division single carrier modulation method using a plurality of frequency bands. The plurality of frequency bands are unused frequency bands that are not used, and are specified by the first control unit 14 as will be described later.

  FIG. 2A is a block diagram illustrating a detailed configuration of the first transmission unit 11. In FIG. 2A, the first transmission unit 11 includes a modulation unit 31, an S / P (serial / parallel) conversion unit 32, a Fourier transform unit 33, a spectrum mapping unit 34, and an inverse Fourier transform unit 35. A P / S (parallel / serial) conversion unit 36, a DA conversion unit 37, a local transmission unit 38, a frequency conversion unit 39, and a power amplification unit 40.

The modulation unit 31 receives communication data that is a digital signal and digitally modulates the communication data. For the purpose of improving PAPR (Peak to Average Power Ratio) characteristics, the modulation waveform before spectrum division may be shaped by a roll-off filter (for example, refer to the following document). Wanna) The S / P converter 32 converts the digitally modulated communication data into a plurality of parallel array signals. When a roll-off filter is used at the time of digital modulation, the output signal near the IFFT frame boundary is distorted, so that the S / P conversion unit 32 and the P / S conversion unit 36 perform overlapping S / P conversion and duplication. P / S conversion may be performed. The overlapping rate may be 1/8, for example.
Literature: Yasuo Suzuki, Hitoshi Yano, Masazumi Ueha, “Shaping effect of spectrum-divided single carrier transmission”, Society Conference of IEICE, B-5-137, p. 491, September 2010

  The Fourier transform unit 33 receives signals in a plurality of parallel arrays after S / P conversion, and converts the signals in the time domain into signals in the frequency domain by performing fast Fourier transform on these signals in parallel. The spectrum mapping unit 34 receives the signal after the fast Fourier transform, and performs spectrum mapping on the signal. Specifically, the spectrum mapping unit 34 divides the signal after the fast Fourier transform into N pieces by a bandpass filter, and the divided N signals have frequencies corresponding to a plurality of frequency bands used for communication. Perform conversion. The spectrum mapping unit 34 converts a plurality of frequency components included in a plurality of divided transmission spectrum blocks, which are signals in a parallel array after fast Fourier transform, to a plurality of frequencies set by the first control unit 14 described later. A mapping matrix for dividing into bands may be generated, and a plurality of frequency components included in a plurality of divided transmission spectrum blocks may be divided into a plurality of frequency bands using the mapping matrix. For detailed processing of the spectrum mapping unit 34, see, for example, Patent Document 1 described above. When overlapping S / P conversion is performed at the time of S / P conversion, the signal phase after frequency conversion becomes discontinuous, and thus phase correction is also performed (see the above document). N is the number of sub-spectrums used in communication, and is an integer of 1 or more. When communication is performed using a plurality of sub-spectrums, N is 2 or more. The inverse Fourier transform unit 35 performs inverse fast Fourier transform on the spectrum-mapped signal and returns it to the time domain signal. The P / S conversion unit 36 receives the signal after the inverse fast Fourier transform, and converts the parallel signal into a serial signal. As described above, the P / S converter 36 may perform overlapping P / S conversion. The DA conversion unit 37 receives a serially arranged digital signal after P / S conversion, and converts the digital signal into an analog signal. The local transmitter 38 generates a signal for frequency conversion. The frequency conversion unit 39 converts the equivalent baseband transmission signal generated by the DA conversion unit 37 into a transmission frequency band using the signal for frequency conversion generated by the local transmission unit 38. The power amplification unit 40 amplifies the transmission signal frequency-converted by the frequency conversion unit 39 to a desired power. The transmission signal is transmitted via the antenna 3.

  In addition, the signal which each component of the 1st transmission part 11 delivers may be only called communication data. In addition, the configuration of the first transmission unit 11 is not limited to this, and may be another configuration as long as the transmission by the spectrum division single carrier modulation method can be performed. For example, S / P conversion or P / S conversion may not be performed, or discrete Fourier transform or inverse discrete Fourier transform may be used instead of fast Fourier transform or inverse fast Fourier transform. As described above, the configuration of the first transmission unit 11 is arbitrary. Further, the first transmission unit 11 may be realized by hardware, or a part that can be realized by software may be realized by software such as a driver that drives the transmission device.

The first receiving unit 12 receives communication data transmitted from the second communication apparatus by a spectrum division single carrier modulation method.
FIG. 2B is a block diagram illustrating a detailed configuration of the first receiving unit 12. 2B, the first receiving unit 12 includes a low noise amplifying unit 41, a frequency converting unit 42, a local transmitting unit 43, an AD converting unit 44, an S / P converting unit 45, and a Fourier transform. Unit 46, spectrum demapping unit 47, inverse Fourier transform unit 48, P / S conversion unit 49, and demodulation unit 50.

  The low noise amplifying unit 41 receives an analog signal of communication data received by the antenna 3 and amplifies the received analog signal (received signal). The frequency converter 42 uses the signal generated by the local transmitter 43 to frequency-convert the received signal, and converts it to an equivalent baseband received signal that can be converted by the AD converter 44. The local transmitter 43 generates a signal for frequency conversion in the frequency converter 42. The AD converter 44 converts an analog signal that is an equivalent baseband received signal into a digital signal. The S / P converter 45 receives the digital signal after AD conversion, and converts the digital signal into a plurality of signals arranged in parallel. The Fourier transform unit 46 receives signals in a plurality of parallel arrays after S / P conversion, and converts the signals in the time domain into signals in the frequency domain by performing fast Fourier transform on these signals in parallel. The spectrum demapping unit 47 receives the signal after the fast Fourier transform and performs spectrum demapping on the signal. Specifically, the spectrum demapping unit 47 divides the signal after the fast Fourier transform into signals of M frequency bands corresponding to a plurality of frequency bands used in communication by a band pass filter, and the divided M A signal corresponding to one frequency band is combined with a signal of one frequency band by performing frequency conversion on the signal. The spectrum demapping unit 47 generates a mapping matrix corresponding to a plurality of frequency bands used in communication of communication data by the same method as the spectrum mapping unit 34, and the demapping which is a transposed matrix of the mapping matrix A matrix may be calculated, and the parallel array signals after the fast Fourier transform may be combined into one frequency band using the demapping matrix. For detailed processing of the spectrum demapping unit 47, refer to, for example, the above-mentioned Patent Document 1. M is the number of sub-spectrums used in communication and is an integer of 1 or more. When communication is performed using a plurality of sub-spectrums, M is 2 or more. In addition, when performing communication using the spectrum division single carrier modulation method, since the number of sub-spectrums of communication data to be transmitted is normally equal to the number of sub-spectrums of communication data to be received, N = M. As will be described later, M may be smaller than N. That is, M ≦ N. This is because in the communication according to the present embodiment, communication is performed without using the frequency band when the transmission path characteristics are not good even in the empty frequency band. The inverse Fourier transform unit 48 performs inverse fast Fourier transform on the signal after the spectrum demapping and returns it to the time domain signal. The P / S converter 49 receives the signal after the inverse fast Fourier transform, and converts the parallel signal into a serial signal. The demodulator 50 receives a serially arranged digital signal after P / S conversion, and digitally demodulates the digital signal.

  Here, also in the first receiving unit 12, a roll-off filter may be used after the spectrum demapping unit 47. In that case, the inverse Fourier transform unit 48 performs an inverse Fourier transform on the signal received from the roll-off filter. When a roll-off filter is used, the S / P conversion unit 45 and the P / S conversion unit 49 may perform overlap S / P conversion and overlap P / S conversion. In addition, when overlapping conversion is performed during S / P conversion, the spectrum demapping unit 47 also performs phase correction so that the signal phase does not become discontinuous.

  In addition, the signal which each component of the 1st receiving part 12 delivers may only be called communication data. In addition, the configuration of the first receiving unit 12 is not limited to this, and may be other configurations as long as the reception by the spectrum division single carrier modulation method can be performed. For example, S / P conversion or P / S conversion may not be performed, or discrete Fourier transform or inverse discrete Fourier transform may be used instead of fast Fourier transform or inverse fast Fourier transform. Further, in the first receiving unit 12, an equalization process using an equalizer (equalizer) may be performed between the Fourier transform unit 46 and the spectrum demapping unit 47. As described above, the configuration of the first receiving unit 12 is arbitrary. The first receiving unit 12 may be realized by hardware, or a part that can be realized by software may be realized by software such as a driver that drives the receiving device.

  The local transmitter 38 in the first transmitter 11 and the local transmitter 43 in the second receiver 12 may be the same. That is, the frequency conversion in the frequency conversion units 39 and 42 may be performed using the same local transmission unit. Further, for example, the frequency generated by the local transmitters 38 and 43 is 2.4 GHz, and the frequency of the transmission signal after frequency conversion by the frequency converter 39 and the frequency of the reception signal received by the antenna 3 are 2. 4 GHz, and the frequency of the transmission signal and reception signal in the equivalent baseband may be 0 GHz. Needless to say, these frequencies are merely examples and are not limited to these.

  The acquisition unit 13 acquires a plurality of vacant frequency bands that are frequency bands that are not used for communication. The acquisition unit 13 may acquire the plurality of vacant frequency bands by detecting (sensing) the vacant frequency band in communication data transmitted by another device (for example, the second communication device 2 or the like). May be acquired from the communication data received by the first receiving unit 12. When detecting a plurality of vacant frequency bands, the acquisition unit 13 may perform detection using the signal after the fast Fourier transform of the first reception unit 12. That is, the acquisition unit 13 compares the power spectrum obtained from the frequency domain signal after the fast Fourier transform with a preset threshold value, and a frequency band having an amplitude larger than the threshold value is used. It may be determined that a frequency band having an amplitude smaller than the threshold is not used. In the present embodiment, a case where the acquisition unit 13 detects a plurality of free frequency bands in this way will be described. Further, when acquiring a plurality of vacant frequency bands from the received communication data, the communication data transmitted from the second communication device 2 includes information indicating the vacant frequency band, and the acquisition unit 13 Information indicating the free frequency band may be acquired from the communication data after digital demodulation. Note that the vacant frequency band may be indicated by, for example, an upper limit frequency and a lower limit frequency of the frequency band, or may be indicated by an index assigned in advance for each frequency band. In the present embodiment, the latter case will be mainly described. The index is sometimes called a frequency index. Further, the acquisition unit 13 may store, for example, information (for example, a frequency itself or a frequency index) that can specify a plurality of acquired empty frequency bands in a recording medium (not shown). As a result, as long as the free frequency band can be known, the processing content performed by the acquisition unit 13 is not limited. For example, the acquisition unit 13 may acquire a frequency band in use. This is because even in such a case, the available frequency band can be known as a result.

  The first control unit 14 causes the first transmission unit 11 to transmit communication data for acquiring transmission path characteristics using a plurality of vacant frequency bands acquired by the acquisition unit 13. The communication data for acquiring the transmission path characteristics may be dummy data used only for acquiring the transmission path characteristics, or an entity that communicates with the second communication device 2 (content to be transmitted by communication). May be included. The communication data for acquiring the transmission path characteristics preferably includes information indicating a plurality of frequency bands used for transmission of the communication data. When the communication data for acquiring the transmission path characteristics is dummy data, the first control unit 14 performs control so that the communication data for acquiring the transmission path characteristics is transmitted when starting communication, Even after that, control may be performed such that communication data for acquiring transmission path characteristics is transmitted periodically or at a timing when the transmission quality deteriorates, or the like. When communication data for transmission path characteristic acquisition is transmitted even after the start of communication, information indicating the frequency (interval) of transmission of communication data for transmission path characteristic acquisition is stored in a recording medium (not shown) The first control unit 14 may cause the first transmission unit 11 to transmit communication data for acquiring transmission path characteristics according to the frequency. The frequency may be received from the second communication device 2 as described later. When the communication data for acquiring transmission path characteristics is dummy data, the communication data may include information indicating that it is for acquiring transmission path characteristics. Communication data for transmission path characteristic acquisition transmitted after the start of communication may be transmitted using a frequency band used for communication at that time, or an empty frequency band by the acquisition unit 13 at that time May be transmitted again using the empty frequency band. Further, when the communication data for acquiring the transmission path characteristics is data including the substance of communication, the transmission path characteristics of the communication data transmitted from the first communication apparatus 1 to the second communication apparatus 2 are included. It can be considered that the communication data used for acquisition becomes communication data for acquiring transmission path characteristics as a result. Even if the communication data for acquiring the transmission path characteristics is data including the substance of the communication, the first control unit 14 acquires the free frequency band after the start of communication. It is also possible to perform control so that communication data for acquiring transmission path characteristics including the substance of communication is transmitted using the empty frequency band. By doing so, it becomes possible to cope with dynamic changes in transmission path characteristics. In addition, when the first receiving unit 12 receives communication data indicating a plurality of frequency bands having good transmission path characteristics among the plurality of frequency bands that have transmitted the communication data for acquiring transmission path characteristics, the first control section 14 causes the first transmitter 11 to transmit communication data using a plurality of frequency bands having good transmission path characteristics. For example, when the frequency index “1”, “3”, “5” is acquired by the acquisition unit 13 as an empty frequency band, the first control unit 14 sends the frequency index “1” to the first transmission unit 11. The communication data for acquiring the transmission path characteristics is transmitted using the frequency band corresponding to “3” and “5”. Thereafter, the first receiving unit 12 receives communication data including the frequency indexes “3” and “5” as frequency bands with good transmission characteristics via the frequency bands corresponding to the frequency indexes “3” and “5”. In this case, the first control unit 14 controls the first transmission unit 11 to transmit the communication data using the frequency band corresponding to the frequency indexes “3” and “5”.

  The second communication device 2 includes a second transmission unit 21, a second reception unit 22, a transmission path characteristic acquisition unit 23, a selection unit 24, a history information recording unit 25, and a second control unit 26. With.

  The 2nd transmission part 21 transmits communication data via the antenna 4 by a spectrum division | segmentation single carrier modulation system using a some frequency band. The configuration of the second transmission unit 21 is the same as the configuration of the first transmission unit 11 shown in FIG. Note that the second transmission unit 21 divides communication data into M sub-spectrums and transmits the data. In the second transmission unit 21 as well, a signal that each component passes is sometimes simply referred to as communication data. Also, the configuration of the second transmitter 21 is not limited to that shown in FIG. 2A, and any other configuration can be used as long as transmission by a spectrum division single carrier modulation method can be performed. Also good. Further, the second transmission unit 21 may be realized by hardware, or a part that can be realized by software may be realized by software such as a driver that drives the transmission device.

  The second receiving unit 22 receives the communication data transmitted from the first communication device 1 by the spectrum division single carrier modulation method via the antenna 4. The configuration of the second receiving unit 22 is the same as the configuration of the first receiving unit 12 shown in FIG. Note that the second receiving unit 22 receives communication data divided into N sub-spectrums. In the second receiving unit 22 as well, a signal that each component passes is sometimes simply referred to as communication data. Further, the configuration of the second receiving unit 22 is not limited to that shown in FIG. 2B, and any other configuration can be used as long as it can perform reception by the spectrum division single carrier modulation method. Also good. Further, the second receiving unit 22 may be realized by hardware, or a part that can be realized by software may be realized by software such as a driver that drives the receiving device.

  The transmission path characteristic acquisition unit 23 acquires transmission path characteristics of a plurality of frequency bands used in communication of communication data for transmission path characteristic acquisition received by the second reception unit 22. For example, the transmission path characteristic acquisition unit 23 may acquire transmission path characteristics that are reception quality of the second reception unit 22 for each of a plurality of frequency bands in which communication data is transmitted. The reception quality may be, for example, received signal strength (RSSI: Received Signal Strength Indication / Indicator), may be an SN ratio, or may be an index indicating other reception quality. Further, the transmission path characteristic acquisition unit 23 may acquire the transmission path characteristic that is the reception quality using, for example, a signal in the frequency domain after the fast Fourier transform in the second reception unit 22. The communication data for acquiring transmission path characteristics is dedicated communication data for checking the quality of the transmission path, and the content of the communication data for acquiring transmission path characteristics is stored in advance in the second communication device 2. If so, the transmission path characteristic acquisition unit 23 compares the received transmission path characteristic acquisition communication data with the previously stored transmission path characteristic acquisition communication data to determine the degree of coincidence. By doing so, the characteristics of the transmission line may be acquired. In this case, the higher the degree of matching, the higher the quality of the transmission path. Also in this case, the transmission path characteristic acquisition unit 23 acquires a transmission path characteristic indicating the degree of coincidence using, for example, a signal in the frequency domain after the fast Fourier transform in the second reception unit 22. Also good. It goes without saying that the transmission path characteristic acquisition unit 23 may acquire the transmission path characteristics by other methods. In addition, for example, when the communication data for acquiring transmission path characteristics includes information indicating a plurality of frequency bands used in transmission of the communication data, the transmission path characteristics acquisition unit 23 Acquire transmission path characteristics for the frequency band.

  The selection unit 24 uses a predetermined condition for determining whether the transmission path characteristics are good or not, and the plurality of frequencies determined that the transmission path characteristics acquired by the transmission path characteristics acquisition unit 23 are better enough to satisfy the conditions. Select the band. The condition for determining that the transmission path characteristic is good may be, for example, that the transmission path characteristic is a value better than a threshold value, or that the transmission path characteristic is within a predetermined number from the better one. It may be present or a combination thereof. Specifically, the selection unit 24 may select a frequency band that is a transmission path characteristic with a value that is better than the threshold value, or select up to a predetermined number of frequency bands that have a better transmission path characteristic. (Conversely, it may be possible not to select a predetermined number of frequency bands from a method with poor transmission path characteristics), and specify a frequency band that is a transmission path characteristic with a value better than the threshold value. Of the identified frequency bands, up to a predetermined number of frequency bands having better transmission path characteristics may be selected. The threshold value may be, for example, a predetermined value, or a coefficient predetermined for the best transmission line characteristic (in the case of a transmission line characteristic that is a better characteristic as the value is higher, for example, It may be a value multiplied by a coefficient less than 1 such as 0.4 or 0.6. Further, the predetermined number may be a predetermined number or a predetermined coefficient (for example, less than 1) in the number of frequency bands used in transmission of communication data for acquiring transmission path characteristics. It may be a value multiplied by 0.8). For the purpose of performing communication using a frequency band with good transmission path characteristics, it is preferable that the selection unit 24 selects a frequency band that has transmission path characteristics with a value better than a threshold value.

  The history information recording unit 25 records history information that is history information of a selection result by the selection unit 24. For example, the history information recording unit 25 may record history information including a time when the selection unit 24 performs selection and a selection result on a recording medium. The history information recording unit 25 may also record identification information of a communication device (for example, the first communication device 1) as a communication destination along with the selection result and the like. The recording medium is, for example, a semiconductor memory, an optical disk, a magnetic disk, or the like, and may be included in the history information recording unit 25 or may exist outside the history information recording unit 25. In addition, the recording medium may temporarily store history information or not.

  The second control unit 26 causes the second transmission unit 21 to transmit communication data indicating a plurality of frequency bands selected by the selection unit 24 using the plurality of frequency bands selected by the selection unit 24. By transmitting the communication data, the first communication device 1 can know a frequency band with good transmission path characteristics. Further, the second control unit 26 may perform control such that acquisition of transmission path characteristics by the transmission path characteristic acquisition unit 23 and selection by the selection unit 24 according to the acquisition result are repeatedly performed. As described above, the communication data for acquiring transmission path characteristics used in acquiring the transmission path characteristics at that time may or may not be transmitted only for that purpose. . In the former case, communication data for acquiring transmission path characteristics repeatedly (as described above, this communication data may be transmitted using the frequency band used for communication at that time, or at that time May be transmitted using a vacant frequency band). In the latter case, the transmission path characteristic acquisition unit 23 may be, for example, specific communication data transmitted from the first communication device 1 (for example, communication data for each predetermined time, The transmission path characteristics may be obtained by regarding the communication data for obtaining the transmission path characteristics as communication data for acquiring transmission path characteristics.

  In addition, the second control unit 26 may perform control such that selection is performed more frequently as the variation of the selected frequency band indicated by the history information is faster. In other words, the second control unit 26 may perform control so that selection is performed less frequently as the variation in the selected frequency band is slower. For example, when the frequency band selected for each selection is different, the selection may be performed at a frequency higher than the selection frequency so far. On the other hand, when the frequency band selected only once in 10 selections is changed, the selection may be performed at a frequency lower than the selection frequency so far. The selection frequency may be controlled, for example, by controlling a selection time interval. Any method may be used as long as the second control unit 26 can perform such control according to the history information as a result. For example, the second control unit 26 may control the selection frequency itself, or may control the selection frequency as a result by controlling the transmission frequency of communication data for acquiring transmission path characteristics. . For example, when the communication data for acquiring the transmission path characteristics is transmitted only for the purpose, the second control unit 26 acquires the transmission path characteristics according to the change of the selection frequency. Communication data instructing to change the transmission frequency of the communication data for use may be transmitted to the first communication device 1. And according to the instruction | indication, the 1st communication apparatus 1 may change the transmission frequency of the communication data for transmission line characteristic acquisition. In addition, the second control unit 26 may transmit communication data for requesting transmission of communication data for acquiring transmission path characteristics to the first communication device 1 at the timing of selection. And according to the request | requirement, the 1st communication apparatus 1 may transmit the communication data for transmission-line characteristic acquisition. For example, the second control unit 26 may calculate the selection frequency using history information and perform control so that selection according to the calculated frequency is performed. When calculating the selection frequency from the history information, as described above, the calculation is performed so that the selection is performed more frequently as the variation of the selected frequency band is faster. The calculated selection frequency may be stored in a recording medium (not shown).

  Further, since the frequency band that is not selected by the selection unit 24 is known to be an empty frequency band, the second control unit 26 may manage the frequency band as an empty frequency band. Then, for example, when allocating a vacant frequency band to another communication device, one managed as the vacant frequency band may be used.

  When the acquisition unit 13 of the first communication device 1 receives a plurality of vacant frequency bands from another device, the second communication device 2 detects a plurality of vacant frequency bands and detects the plurality of detected frequency bands. Communication data indicating the available frequency band may be transmitted to the first communication device 1.

Next, operation | movement of the 1st communication apparatus 1 is demonstrated using the flowchart of FIG.
(Step S101) The first transmission unit 11 determines whether or not to perform transmission. If transmission is to be performed, the process proceeds to step S102. If not, the process of step S101 is repeated until it is determined that transmission is to be performed. For example, the first transmission unit 11 may determine that transmission is performed when an instruction to transmit communication data to the second communication device 2 is received from an upper layer such as an application. It may be determined that transmission is performed at the timing.

  (Step S102) The acquisition unit 13 acquires a plurality of vacant frequency bands.

  (Step S <b> 103) The first control unit 14 controls the first transmission unit 11 to transmit communication data for acquiring transmission path characteristics using a plurality of vacant frequency bands acquired by the acquisition unit 13. That is, the first control unit 14 sets a plurality of vacant frequency bands acquired by the acquisition unit 13 to frequency bands where the first transmission unit 11 transmits communication data. As a result, the first transmission unit 11 divides the transmission data for acquiring the transmission path characteristics into a plurality of sub-spectrums corresponding to the plurality of free frequency bands and transmits the data.

  (Step S104) The first receiving unit 12 determines whether or not the communication data transmitted from the second communication device 2 has been received. If received, the process proceeds to step S105, and if not, the process proceeds to step S107.

  (Step S105) The first control unit 14 determines whether the communication data received by the first receiving unit 12 includes information indicating a frequency band used for communication. If the communication data includes information indicating the frequency band, it is determined whether or not the frequency band indicated by the information is the same as the frequency band used for transmission of the communication data so far. If they are different, the process proceeds to step S106. If they are the same, or if the received communication data does not include information indicating the frequency band, the process returns to step S104.

  (Step S106) The first controller 14 transmits the changed frequency band indicated by the information included in the communication data received by the first receiver 12, and the first transmitter 11 transmits the communication data. Set to the frequency band to be used. Therefore, after that, when the first transmission unit 11 transmits communication data, it is transmitted in the changed frequency band. Then, the process returns to step S104.

  (Step S107) The first transmitter 11 determines whether to transmit communication data. And when transmitting communication data, it progresses to step S108, and when that is not right, it progresses to step S109. For example, the first transmission unit 11 may determine that transmission is performed when an instruction to transmit communication data to the second communication device 2 is received from an upper layer such as an application. It may be determined that transmission is performed at the timing.

  (Step S108) The first transmission unit 11 transmits the communication data by dividing it into a plurality of sub-spectrums corresponding to a plurality of frequency bands set at that time. Then, the process returns to step S104.

(Step S109) The first control unit 14 determines whether to acquire a plurality of vacant frequency bands again. If the acquisition is performed again, the process returns to step S102. If not, the process returns to step S104. For example, the first control unit 14 may determine to periodically acquire a plurality of vacant frequency bands, and acquire a plurality of vacant frequency bands in response to an instruction from the second communication device 2. It may be determined that a plurality of vacant frequency bands are acquired at a timing when a drop in transmission path quality is detected, or when a plurality of vacant frequency bands are acquired at other timings. You may judge.
In the flowchart of FIG. 3, the process ends when the power is turned off or the process is terminated.

Next, the operation of the second communication device 2 will be described using the flowchart of FIG.
(Step S201) The second receiving unit 22 determines whether communication data has been received. If the communication data is received, the process proceeds to step S202. If not, the process of step S201 is repeated until the communication data is received.

  (Step S202) The transmission path characteristic acquisition unit 23 acquires transmission path characteristics according to the communication data received in step S201 or step S207. The transmission path characteristics are acquired for each of a plurality of frequency bands used for transmission of communication data.

  (Step S203) The selection unit 24 selects a plurality of frequency bands with good transmission path characteristics acquired by the transmission path characteristics acquisition unit 23.

  (Step S204) The second control unit 26 controls the second transmission unit 21 to transmit the communication data indicating the selection result using the plurality of frequency bands selected by the selection unit 24. That is, the second control unit 26 sets a plurality of frequency bands selected by the selection unit 24 to frequency bands at which the second transmission unit 21 transmits communication data. In addition, the second control unit 26 passes communication data indicating the selection result to the second transmission unit 21. Then, the second transmission unit 21 divides and transmits the communication data indicating the selection result into a plurality of sub-spectrums corresponding to the selected plurality of frequency bands.

  (Step S205) The history information recording unit 25 accumulates history information including the current time, the selection result, and the identification information of the first communication device 1 in a recording medium (not shown).

  (Step S206) The second control unit 26 refers to the history information accumulated by the history information recording unit 25 and updates the selection frequency. That is, the selection frequency corresponding to the history information at that time is calculated, and the selection frequency is stored in a recording medium (not shown) by overwriting. If selection is performed at an appropriate frequency, the selection frequency may not be changed as a result.

  (Step S207) The second receiving unit 22 determines whether communication data has been received. If it is received, the process proceeds to step S208. If not, the process proceeds to step S209.

  (Step S208) The selection unit 24 determines whether it is time to perform selection. If it is time to make a selection, the process returns to step S202. If not, the process returns to step S207. For example, the selection unit 24 may determine that it is a timing to perform selection when a selection time interval has elapsed from the previous selection time point, and when communication data for transmission path characteristic acquisition is received, It may be determined that it is time to perform selection, or it may be determined that it is time to perform selection at other timing. In addition, when it is necessary to request transmission of communication data for acquiring transmission path characteristics when acquiring transmission path characteristics, it is determined from step S208 to Y before returning to step S202. Transmission of communication data requesting transmission of communication data for acquiring transmission path characteristics to the first communication device 1 and reception of communication data for acquiring transmission path characteristics transmitted in response thereto may be performed.

  (Step S209) The second transmission unit 21 determines whether to transmit communication data. And when transmitting communication data, it progresses to step S210, and when that is not right, it returns to step S207.

(Step S210) The second transmission unit 21 transmits communication data using a plurality of frequency bands selected last by the selection unit 24. That is, the second transmission unit 21 divides the communication data into a plurality of sub-spectrums corresponding to the plurality of frequency bands and transmits the data. Then, the process returns to step S207.
In the flowchart of FIG. 4, the process ends when the power is turned off or the process ends.

  Next, the operation of the communication system 100 according to the present embodiment will be described using a specific example. In this specific example, it is assumed that the first communication device 1 is an MS and the second communication device 2 is an AP. In this specific example, it is assumed that a frequency index is assigned to the frequency band in advance.

  It is assumed that the first communication device 1 that is an MS has to communicate with the second communication device 2 that is an AP. Then, the first transmission unit 11 determines to perform transmission (step S101), and passes an instruction to acquire a free frequency band to the acquisition unit 13 via a path (not shown). Then, the acquisition unit 13 performs sensing at that time. That is, the first reception unit 12 determines whether a frequency band is used for each frequency index using the result of the fast Fourier transform of the radio wave received at that time. In this case, it is assumed that, as a result of sensing, it is detected that the frequency band corresponding to the frequency indexes # 2, # 4, etc. is used as shown in FIG. 5A (step S102). Then, the 1st control part 14 sets frequency index # 1, # 3, # 5 which is not used for the frequency band used by transmission of communication data. Further, the first control unit 14 passes the communication data including the frequency indexes # 1, # 3, and # 5 to the first transmission unit 11. As a result, as shown in FIG. 5 (b), the first transmission unit 11 transmits the communication data for acquiring channel characteristics including the frequency indexes # 1, # 3, and # 5 to the set frequency index #. It is divided into frequency bands corresponding to 1, # 3, # 5 and transmitted (step S103).

  The communication data for transmission path characteristic acquisition transmitted from the first communication device 1 is received by the second receiving unit 22 (step S201). Then, the transmission path characteristics acquisition unit 23 acquires the transmission path characteristics corresponding to the frequency indexes # 1, # 3, and # 5 included in the communication data (step S202). Here, it is assumed that the transmission path characteristics are acquired as shown in FIG. That is, it is assumed that the transmission path characteristics of the frequency band corresponding to the frequency index # 1 are bad. As a result, the selection unit 24 compares the preset threshold value with the acquired transmission line characteristics of the frequency indexes # 1, # 3, and # 5, and the transmission line characteristic of the frequency index # 1 is the threshold value. It is determined that the frequency index is less than or equal to the value, and it is assumed that frequency indexes # 3 and # 5 are selected (step S203). Then, the 2nd control part 26 sets the frequency band according to selected frequency index # 3, # 5 to the frequency band used by transmission of communication data. The second control unit 26 passes communication data indicating the selected frequency indexes # 3 and # 5 to the second transmission unit 21. Then, the second transmission unit 21 divides the received communication data into frequency bands corresponding to the set frequency indexes # 3 and # 5 and transmits them (step S204). Further, the history information recording unit 25 accumulates history information having the current time, the selected frequency indexes # 3 and # 5, and the identification information of the first communication device 1 in a recording medium (not shown) ( Step S205). In this case, since the history information is still recorded for the first time, the selection frequency is not updated (step S206). It is assumed that 1 minute is set as the initial value of the selection frequency (selection time interval). If the two adjacent selection results are the same, the selection time interval is doubled (assuming that the upper limit time interval is set), and the two adjacent selection results If they are different, the selection time interval is changed to half. The selection time interval is also transmitted to the first communication device 1, and the first communication device 1 is also used to acquire a free frequency band and acquire transmission path characteristics at the same interval as the selection time interval. It is assumed that the communication data is set to be transmitted. Therefore, also in the first communication apparatus 1, it is assumed that 1 minute is set as an initial value of a time interval such as acquisition of an empty frequency band.

  Communication data transmitted from the second communication device 2 is received by the first receiving unit 12 (step S104). The communication data includes frequency indexes # 3 and # 5, and the frequency indexes # 3 and # 5 are different from the frequency indexes # 1, # 3 and # 5 set so far. Therefore (step S105), the first control unit 14 sets frequency indexes # 3 and # 5 indicating the new frequency band to the frequency band used by the first transmission unit 11 for transmission of communication data (step S106). . Thereafter, when the first communication device 1 transmits communication data to the second communication device 2, the second transmission unit 21 uses a frequency band corresponding to the set frequency indexes # 3 and # 5. (Steps S107 and S108).

  When one minute has elapsed since the transmission of the transmission line characteristic acquisition communication data, the first control unit 14 determines that the free frequency band is acquired again (step S109). Then, transmission of communication data for acquiring transmission path characteristics according to the sensing result is performed (steps S102 and S103). Here again, it is assumed that the empty frequency bands are frequency indexes # 1, # 3, and # 5. The communication data for acquiring the transmission path characteristics is received by the second receiving unit 22 (step S207), and since the communication data is communication data for acquiring the transmission path characteristics, it is determined that the selection is performed (step S207). S208). Then, as described above, acquisition of transmission path characteristics, selection of a frequency band, transmission of communication data according to the selection result, and recording of history information are performed (steps S202 to S205). It is assumed here that frequency indexes # 3 and # 5 are selected. Then, since the same selection result was obtained twice consecutively, the second control unit 26 sets the selection time interval to 2 minutes, and passes the communication data indicating the time interval to the second transmission unit 21. Then, the 2nd transmission part 21 transmits the communication data to the 1st communication apparatus 1 using the frequency band according to frequency index # 3, # 5 currently set (step S209,). S210). The first communication device 1 receives the communication data (steps S104 and S105), and updates the time interval such as acquisition of an empty frequency band to 2 minutes accordingly. In this way, the first and second communication devices 1 and 2 perform communication using a frequency band with good transmission path characteristics.

  In this specific example, the case where there is only one first communication device 1 that is an MS has been described, but this need not be the case. A plurality of MSs similar to the first communication device 1 exist, and the second communication device 2 that is an AP may perform processing such as selection of a frequency band with good transmission path characteristics on the plurality of MSs. Good.

  As described above, according to the communication system 100 according to the present embodiment, there is an empty frequency band between the first and second communication apparatuses 1 and 2 that perform communication by the spectrum division single carrier modulation method, and Thus, communication can be performed using a frequency band with good transmission quality. As a result, it is possible to avoid a decrease in transmission quality. In addition, since a frequency band with poor transmission path characteristics is not occupied, radio resources can be used effectively.

In the present embodiment, the second communication apparatus 2 records history information, and performs control such that selection is performed more frequently as the variation in the selected frequency band indicated by the history information is faster. Although the case has been described, this need not be the case. The selection of the frequency band may be performed at a predetermined frequency. As described above, when the frequency band selection frequency is not controlled using the history information, the second communication device 2 may not include the history information recording unit 25, and the second The control unit 26 may not control the selection frequency.
Further, the communication according to the present embodiment may be performed in the ISM band, for example, or may be performed in a band other than that.

  In the above embodiment, each process or each function may be realized by centralized processing by a single device or a single system, or may be distributedly processed by a plurality of devices or a plurality of systems. It may be realized by doing.

  In the above embodiment, the information exchange between the components is performed by one component when, for example, the two components that exchange the information are physically different from each other. It may be performed by outputting information and receiving information by the other component, or when two components that exchange information are physically the same, one component May be performed by moving from the phase of the process corresponding to to the phase of the process corresponding to the other component.

  In the above embodiment, information related to processing executed by each component, for example, information received, acquired, selected, generated, transmitted, or received by each component In addition, information such as threshold values, mathematical formulas, addresses, etc. used by each component in processing is retained temporarily or over a long period of time on a recording medium (not shown) even when not explicitly stated in the above description. It may be. Further, the storage of information in the recording medium (not shown) may be performed by each component or a storage unit (not shown). Further, reading of information from the recording medium (not shown) may be performed by each component or a reading unit (not shown).

  In the above embodiment, when information used by each component, for example, information such as a threshold value, an address, and various setting values used by each component may be changed by the user Even if it is not specified in the above description, the user may be able to change the information as appropriate, or it may not be. If the information can be changed by the user, the change is realized by, for example, a not-shown receiving unit that receives a change instruction from the user and a changing unit (not shown) that changes the information in accordance with the change instruction. May be. The change instruction received by the receiving unit (not shown) may be received from an input device, information received via a communication line, or information read from a predetermined recording medium, for example. .

  In the above embodiment, when two or more components included in the first and second communication apparatuses 1 and 2 have a communication device, an input device, etc., the two or more components are physically single. Or may have separate devices.

  In the above embodiment, each component may be configured by dedicated hardware, or a component that can be realized by software may be realized by executing a program. For example, each component can be realized by a program execution unit such as a CPU reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. In addition, the software which implement | achieves the 1st communication apparatus 1 in the said embodiment is the following programs. In other words, this program is a program for causing a computer to function as a communication device that performs communication using a free frequency band, and acquires a plurality of free frequency bands that are frequency bands that are not used for communication. The transmission data for acquiring transmission path characteristics is transmitted to the transmission unit using a plurality of vacant frequency bands acquired by the acquisition unit, and the communication data is transmitted using a plurality of frequency bands by a spectrum division single carrier modulation method. Communication data indicating a plurality of frequency bands having good transmission path characteristics among a plurality of frequency bands transmitted from the communication destination apparatus and transmitted from the communication destination apparatus. From the reception unit that receives the communication data transmitted by the spectrum division single carrier modulation method. Is a program for functioning as a control unit for transmitting a communication data to the transmitting unit using a plurality of frequency bands good road characteristics.

  Moreover, the software which implement | achieves the 2nd communication apparatus 2 in the said embodiment is the following programs. In other words, this program is a program for causing a computer to function as a communication device that performs communication using a vacant frequency band, and receives communication data transmitted by a spectrum division single carrier modulation method from a communication destination device. When the receiving unit receives communication data for acquiring transmission path characteristics transmitted using a plurality of vacant frequency bands from the communication destination device, it is used for communication of communication data for acquiring the transmission path characteristics. A transmission path characteristic acquisition unit that acquires transmission path characteristics of a plurality of frequency bands, the transmission path characteristics acquired by the transmission path characteristic acquisition unit using a predetermined condition for determining whether the transmission path characteristics are good or bad Is a selection unit that selects a plurality of frequency bands that are determined to satisfy the condition, and communication that indicates the plurality of frequency bands selected by the selection unit. To function as a control unit that transmits communication data to a transmission unit that transmits data using a plurality of frequency bands by a spectrum division single carrier modulation method using a plurality of frequency bands selected by the selection unit. It is a program.

  In the program, the functions realized by the program do not include functions that can be realized only by hardware. That is, functions that can be realized only by hardware are not included at least in the functions realized by the program.

  Further, this program may be executed by being downloaded from a server or the like, and a program recorded on a predetermined recording medium (for example, an optical disk such as a CD-ROM, a magnetic disk, a semiconductor memory, or the like) is read out. May be executed by Further, this program may be used as a program constituting a program product.

  Further, the computer that executes this program may be singular or plural. That is, centralized processing may be performed, or distributed processing may be performed.

  FIG. 6 is a schematic diagram illustrating an example of an external appearance of a computer that executes the program and realizes the first and second communication apparatuses 1 and 2 according to the embodiment. The above-described embodiment can be realized by computer hardware and a computer program executed on the computer hardware.

  In FIG. 6, a computer system 900 includes a computer 901 including a CD-ROM (Compact Disk Read Only Memory) drive 905, an FD (Floppy (registered trademark) Disk) drive 906, a keyboard 902, a mouse 903, a monitor 904, and the like. Is provided.

  FIG. 7 is a diagram showing an internal configuration of the computer system 900. In FIG. 7, in addition to the CD-ROM drive 905 and the FD drive 906, a computer 901 is connected to an MPU (Micro Processing Unit) 911, a ROM 912 for storing a program such as a bootup program, and the MPU 911. A RAM (Random Access Memory) 913 that temporarily stores program instructions and provides a temporary storage space, a hard disk 914 that stores application programs, system programs, and data, and an MPU 911 and a ROM 912 are interconnected. And a bus 915. Note that the computer 901 may include hardware for performing the above-described transmission and reception processing, for example, a DA converter, an AD converter, a modulator, a demodulator, or the like. It may be connected. The computer 901 may include a network card (not shown) that provides connection to the LAN.

  A program that causes the computer system 900 to execute the functions of the first and second communication apparatuses 1 and 2 according to the above-described embodiments is stored in the CD-ROM 921 or the FD 922, and the CD-ROM drive 905 or the FD drive 906. And may be transferred to the hard disk 914. Instead, the program may be transmitted to the computer 901 via a network (not shown) and stored in the hard disk 914. The program is loaded into the RAM 913 when executed. The program may be loaded directly from the CD-ROM 921, the FD 922, or the network.

  The program does not necessarily include an operating system (OS) or a third-party program that causes the computer 901 to execute the functions of the first and second communication apparatuses 1 and 2 according to the above-described embodiment. The program may include only a part of an instruction that calls an appropriate function (module) in a controlled manner and obtains a desired result. How the computer system 900 operates is well known and will not be described in detail.

  Further, the present invention is not limited to the above-described embodiment, and various modifications are possible, and it goes without saying that these are also included in the scope of the present invention.

  As described above, according to the communication system and the like according to the present invention, it is possible to avoid the deterioration of transmission quality, and it is useful as a communication system that performs communication using a spectrum division single carrier modulation method.

DESCRIPTION OF SYMBOLS 1 1st communication apparatus 2 2nd communication apparatus 3, 4 Antenna 11 1st transmission part 12 1st reception part 13 Acquisition part 14 1st control part 21 2nd transmission part 22 2nd reception part 23 Transmission path characteristic acquisition unit 24 Selection unit 25 History information recording unit 26 Second control unit 31 Modulation unit 32, 45 S / P conversion unit 33, 46 Fourier transform unit 34 Spectrum mapping unit 35, 48 Inverse Fourier transform unit 36, 49 P / S converter 37 DA converter 38, 43 Local transmitter 39, 42 Frequency converter 40 Power amplifier 41 Low noise amplifier 44 AD converter 47 Spectrum demapping unit 50 Demodulator

Claims (8)

A communication system comprising a first communication device and a second communication device that communicate with each other using an empty frequency band,
The first communication device is:
A first transmitter that transmits communication data using a plurality of frequency bands by a spectrum division single carrier modulation method;
A first receiving unit for receiving communication data transmitted from the second communication device;
An acquisition unit for acquiring a plurality of vacant frequency bands that are not used for communication;
A plurality of frequency bands in which communication data for acquiring transmission path characteristics is transmitted to the first transmission section using a plurality of free frequency bands acquired by the acquisition section, and the communication data for acquiring transmission path characteristics is transmitted. When the first receiving unit receives communication data indicating a plurality of frequency bands having good transmission path characteristics, the communication data is transmitted to the first transmission unit using the plurality of frequency bands having good transmission path characteristics. A first control unit for transmitting
The second communication device is:
A second receiver for receiving communication data transmitted from the first communication device;
A second transmitter that transmits communication data using a plurality of frequency bands by a spectrum division single carrier modulation method;
A transmission line characteristic acquisition unit that acquires transmission line characteristics of a plurality of frequency bands used in communication of communication data for transmission line characteristic acquisition received by the second reception unit;
Using a predetermined condition for determining the quality of the transmission path characteristics, the transmission path characteristics acquired by the transmission path characteristics acquisition unit select a plurality of frequency bands that are determined to be good enough to satisfy the conditions. A selection section;
A second control unit that transmits communication data indicating a plurality of frequency bands selected by the selection unit to the second transmission unit using the plurality of frequency bands selected by the selection unit. system. The second control unit performs control such that acquisition of transmission line characteristics by the transmission line characteristic acquisition unit and selection by the selection unit according to the acquisition result are repeatedly performed,
The second communication device is:
A history information recording unit that records history information that is history information of a selection result by the selection unit;
The communication system according to claim 1, wherein the second control unit performs control such that selection is performed more frequently as the variation of the selected frequency band indicated by the history information is faster. A communication device that performs communication using an empty frequency band,
A transmission unit that transmits communication data by a spectrum division single carrier modulation method using a plurality of frequency bands;
A receiving unit for receiving communication data transmitted by a spectrum division single carrier modulation method from a communication destination device;
An acquisition unit for acquiring a plurality of vacant frequency bands that are not used for communication;
Communication data for acquisition of transmission path characteristics, which is transmitted from the communication destination device by causing the transmission section to transmit communication data for acquisition of transmission path characteristics using a plurality of free frequency bands acquired by the acquisition section. When the reception unit receives communication data indicating a plurality of frequency bands with good transmission path characteristics among the plurality of frequency bands transmitted, the communication to the transmission section is performed using the plurality of frequency bands with good transmission path characteristics. And a control unit that transmits data. A communication device that performs communication using an empty frequency band,
A transmission unit that transmits communication data by a spectrum division single carrier modulation method using a plurality of frequency bands;
A receiving unit for receiving communication data transmitted by a spectrum division single carrier modulation method from a communication destination device;
When the receiving unit receives communication data for acquiring transmission path characteristics transmitted from the communication destination device using a plurality of free frequency bands, it is used for communication of communication data for acquiring the transmission path characteristics. A transmission path characteristic acquisition unit that acquires transmission path characteristics of a plurality of frequency bands obtained;
Using a predetermined condition for determining the quality of the transmission path characteristics, the transmission path characteristics acquired by the transmission path characteristics acquisition unit select a plurality of frequency bands that are determined to be good enough to satisfy the conditions. A selection section;
And a control unit that causes the transmission unit to transmit communication data indicating the plurality of frequency bands selected by the selection unit using the plurality of frequency bands selected by the selection unit. A communication method for performing communication using an empty frequency band,
An acquisition step of acquiring a plurality of vacant frequency bands that are frequency bands that are not used for communication;
A first transmission step of transmitting communication data for transmission path characteristic acquisition using a plurality of vacant frequency bands acquired in the acquisition step by a spectrum division single carrier modulation method;
Receives communication data indicating a plurality of frequency bands having good transmission path characteristics among a plurality of frequency bands transmitted from the communication destination apparatus by the spectrum division single carrier modulation method and transmitting the communication data for acquiring the transmission path characteristics. Receiving step;
And a second transmission step of transmitting communication data by a spectrum division single carrier modulation method using a plurality of frequency bands having good transmission path characteristics indicated by the communication data received in the reception step. A communication method for performing communication using an empty frequency band,
A reception step of receiving communication data for acquiring transmission path characteristics transmitted by a spectrum division single carrier modulation method using a plurality of free frequency bands from a communication destination device;
A transmission path characteristic acquisition step of acquiring transmission path characteristics of a plurality of frequency bands used in communication of communication data for transmission path characteristics acquisition received in the reception step;
Using a predetermined condition for judging the quality of the transmission path characteristics, a plurality of frequency bands determined that the transmission path characteristics acquired in the transmission path characteristics acquisition step are good enough to satisfy the conditions are selected. A selection step;
A transmission step of transmitting communication data indicating a plurality of frequency bands selected in the selection step to the communication destination device by a spectrum division single carrier modulation method using the plurality of frequency bands selected in the selection step; Communication method. Computer
A program for functioning as a communication device that performs communication using an empty frequency band,
An acquisition unit that acquires a plurality of vacant frequency bands that are frequency bands that are not used for communication,
Transmission data for transmission path characteristic acquisition is transmitted to a transmission unit that transmits the communication data using a plurality of vacant frequency bands acquired by the acquisition unit using a plurality of frequency bands by a spectrum division single carrier modulation method. Communication data indicating a plurality of frequency bands having good transmission path characteristics among a plurality of frequency bands transmitted from the communication destination apparatus and transmitting communication data for acquiring the transmission path characteristics is transmitted from the communication destination apparatus. When the reception unit that receives communication data transmitted by the spectrum division single carrier modulation method receives, it functions as a control unit that causes the transmission unit to transmit communication data using a plurality of frequency bands having good transmission path characteristics. Program to let you. Computer
A program for functioning as a communication device that performs communication using an empty frequency band,
A communication unit that receives communication data transmitted by a spectrum division single carrier modulation method from a communication destination device is transmitted from the communication destination device using a plurality of vacant frequency bands. When receiving data, a transmission path characteristic acquisition unit that acquires transmission path characteristics of a plurality of frequency bands used in communication of communication data for acquiring the transmission path characteristics,
Using a predetermined condition for determining the quality of the transmission path characteristics, the transmission path characteristics acquired by the transmission path characteristics acquisition unit select a plurality of frequency bands that are determined to be good enough to satisfy the conditions. Selection part,
The communication data indicating the plurality of frequency bands selected by the selection unit is transmitted using the plurality of frequency bands selected by the selection unit, and the communication data is transmitted by the spectrum division single carrier modulation method using the plurality of frequency bands. A program for causing a transmission unit to function as a control unit to transmit.

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