JP2001103034A - Communication system, selecting device, transmitter, receiver, selection method, transmission method, reception method and information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system of an OFDM transmission system. SOLUTION: A selecting device 201 of a communication system 101 selects the number of sub carriers of the OFDM transmission system and transmits information designating it to a transmitter 301 and a receiver 401. The transmitter 301 accepts a signal to be transmitted, also receives information designating the number of sub carriers transmitted from the device 201, and processes and transmits a signal to be transmitted by the OFDM transmission system of the pertinent number of sub carriers. The receiver 401 receives the signal transmitted from the transmitter 301 and also the information designating the number of sub carriers, processes the signal received by the OFDM transmission system of the pertinent number of sub carriers and obtains the transmitted signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an orthogonal frequency division multiplexing (O
The present invention relates to a communication system using a transmission method (FDM), a selection device, a transmission device, a reception device, a selection method, a transmission method, a reception method, and an information recording medium.

[0002]

2. Description of the Related Art Conventionally, an OFDM transmission type communication system using a Fourier transform and an inverse Fourier transform has been proposed. The OFDM transmission method is a type of a multi-carrier transmission method. FIG. 1 is a schematic diagram showing a schematic configuration of such a communication system of the OFDM transmission system. Hereinafter, description will be made with reference to FIG.

The communication system 11 includes a transmitting device 21 and a receiving device 31. The transmitting device 21 appropriately converts a signal to be transmitted and transmits the signal to the receiving device 31 by radio, and the receiving device 31 converts the received signal. The transmitted signal is obtained by performing appropriate inverse conversion.

[0004] A transmitting device 21 receives a signal to be transmitted, and pre-processes the signal with a pre-processing unit 22. If the signal to be transmitted is a digital signal, in the preprocessing, the signal is assigned to the I channel and the Q channel, and modulation is performed.

On the other hand, if the signal to be transmitted is an analog signal, the analog signal is sampled at predetermined time intervals, converted into a digital signal, and then subjected to the above preprocessing.

The pre-processed signal is supplied to a serial / parallel converter 2
3 performs serial-to-parallel conversion into a plurality of signals, and performs an inverse Fourier transform
4 is the Inverse Fast Fourier Transform
formation; IFFT).

[0007] The inverse Fourier transform unit 24 outputs a plurality of signals representing a time series of signals such that the input signals are orthogonal frequency components.

These signals are converted by the parallel-to-serial converter 25 into a single analog signal. Further, the signal is converted into an analog signal by a quadrature modulator and a digital-analog converter included in the transmitting unit 26, and at this time, the signal is transmitted to the receiving device 31 after up-converting the frequency.

On the other hand, in the receiving device 31, the receiving unit 32 receives the analog signal transmitted by the transmitting device 21, downconverts the frequency, and obtains a single digital signal by the quadrature demodulator and the analog-digital converter. .

Further, this signal is converted into a plurality of signals by a serial / parallel converter 33 in the same manner as the transmitting device 21, and these are converted by a Fourier transformer 34 into a fast Fourier transform (Fast Fourier transform).
Carrier Transformation (FFT).

The Fourier transform unit 34 treats a plurality of input signals as a time series, and outputs a plurality of signals representing frequency components of the signals.

Therefore, these are converted into a parallel-to-serial converter 35.
, A single signal is obtained, and a post-processing unit 36 performs post-processing on the single signal to obtain a transmitted signal.

In the post-processing, the frequency of the signal is reduced to a frequency that facilitates analog-digital conversion, and a signal separated into I and Q channels is created.

If the transmitted signal is an analog signal, the demodulated signal is further subjected to digital-to-analog conversion.

The OFDM transmission system is receiving attention as a method for obtaining excellent reception characteristics under a multipath radio wave propagation environment, and is being applied to the field of mobile communications in addition to digital broadcasting. In the OFDM transmission method, the transmission signal is
It is characterized in that it is divided into a plurality of narrow-band subcarriers orthogonal to each other and transmitted by the inverse Fourier transform.

FIG. 2 is an explanatory diagram showing a state of a frequency spectrum of a signal of such an OFDM transmission system. FIG.
As shown in (1), at the frequency where each subcarrier has a peak, the frequency components of the other subcarriers are zero. This is the reason that the frequencies are orthogonal.

[0017]

However, in the case of land mobile radio communication, frequency resources are finite,
There is a great demand to dynamically adjust the number of subcarriers used in the FDM transmission system to perform communication according to the radio wave propagation environment.

On the other hand, PDC (Personal Digital Cellu
In the case of a cellular system such as a lar) system, a cell composed of small zones in which a service area is divided is set, and cells in which the interference between cells is sufficiently attenuated depending on the distance, use the same frequency channel to utilize frequency resources. To increase the efficiency of use. For example, in a case where users in the same cell communicate at the same time, a Time Division Multiple Access (TDMA) transmission method is adopted to improve the subscriber capacity. An OFDM transmission system that can be used in combination with such a communication mode is desired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is suitable for selecting the number of subcarriers of the OFDM transmission system as required, a communication device, a selection device, a transmission device, and a reception device. It is an object of the present invention to provide an apparatus, a selection method, a transmission method, a reception method, and an information recording medium on which a program for realizing the method is recorded.

[0020]

In order to achieve the above object, the following invention is disclosed in accordance with the principle of the present invention.

[0021] The communication system of the present invention is configured to include a selecting device, a transmitting device, and a receiving device.

The selecting device selects the number of subcarriers for orthogonal frequency division multiplexing transmission, and transmits information designating the selected number of subcarriers to the transmitting device and the receiving device.

The transmitting device receives a signal to be transmitted,
Receiving information designating the number of subcarriers transmitted from the selection device, converting the received signal into a signal having the number of subcarriers in parallel / serial, outputting the signal, and converting the signal output in serial / parallel conversion into an inverse signal. The signal of the number of subcarriers is output by Fourier transform, the signal output by inverse Fourier transform is output by parallel-to-serial conversion, and the signal output by parallel-serial conversion is output to the receiving device.

The receiving device receives the signal transmitted from the transmitting device, receives the information specifying the number of subcarriers transmitted from the selecting device, and converts the received signal into a signal in parallel with the signal of the number of subcarriers. Convert and output, output the signal that is serial-parallel converted and output, Fourier transform and output the signal of the number of sub-carriers, output the signal that has been Fourier transformed and output, output a signal that is parallel-to-serial converted, The signal output from the parallel-to-serial conversion is output as a transmitted signal.

Further, the selection device of the communication system of the present invention further receives an input of the number of subcarriers for orthogonal frequency division multiplexing transmission, and specifies the number of received subcarriers as a subcarrier specified by information to be transmitted. It can be configured to be selected as a number.

In the present invention, according to a user's instruction,
The number of subcarriers in the OFDM transmission system is changed.

Further, the selecting device of the communication system of the present invention further measures communication traffic (traffic), the number of slots previously associated with the measured communication traffic, the slot number to be used, and , And a value obtained by dividing a predetermined constant by the number of slots is selected as the number of subcarriers specified by the information to be transmitted, and the information to be transmitted further specifies the number of slots and the slot number. It is constituted so that.

On the other hand, the transmitting device further performs time division by the number of slots specified by the information transmitted from the selecting device, and transmits a signal to the receiving device using the slot of the slot number specified by the information. The configuration is as follows.

On the other hand, the receiving apparatus further performs time division by the number of slots specified by the information transmitted from the selecting apparatus, and receives a signal from the transmitting apparatus using the slot of the slot number specified by the information. The configuration is as follows.

In particular, the configuration is such that the higher the communication traffic, the greater the number of slots associated therewith.

According to the present invention, the number of subcarriers allocated to each user is changed according to communication traffic, and an OFDM transmission system using a TDMA transmission system can be realized accordingly.

Further, the selecting device of the communication system of the present invention is formed integrally with the transmitting device, the transmitting device transmits the information to the transmitting device by wire, and the selecting device transmits the information to the receiving device wirelessly. The transmitting device may be configured to wirelessly transmit the signal to the receiving device.

Further, the selecting device of the communication system of the present invention is configured integrally with the receiving device, the selecting device transmits the information to the receiving device by wire, and the selecting device transmits the information to the transmitting device. Transmitting wirelessly, the transmitting device can be configured to wirelessly transmit the signal to the receiving device.

Further, the selecting device of the communication system of the present invention transmits the information to the transmitting device and the receiving device wirelessly, and the transmitting device wirelessly transmits the signal to the receiving device. can do.

[0035] The selection device of the present invention is configured to include a selection unit and a transmission unit.

Here, the selection unit selects the number of subcarriers for orthogonal frequency division multiplex transmission.

[0037] The transmitting unit transmits information designating the selected number of subcarriers to the transmitting device and the receiving device.

Further, the selecting device of the present invention can be configured to further include an input receiving unit.

Here, the input receiving unit receives an input of the number of subcarriers for orthogonal frequency division multiplex transmission.

The selection section selects the number of subcarriers whose input has been accepted.

Further, the selecting device of the present invention can be configured to further include a measuring unit and an acquiring unit.

Here, the measuring section measures communication traffic.

The acquisition unit acquires the number of slots previously associated with the measured communication traffic and the slot number to be used.

The selector selects a value obtained by dividing a predetermined constant by the obtained number of slots as the number of subcarriers.

The transmitting unit transmits information for specifying the number of slots and the slot number.

Further, the transmitting section of the selecting device of the present invention can be configured to transmit the information wirelessly.

The transmitting apparatus of the present invention is configured to include a signal receiving unit, an information receiving unit, a serial-to-parallel converter, an inverse Fourier transformer, a parallel-serial converter, and a transmitter.

Here, the signal receiving unit receives a signal to be transmitted.

[0049] The information receiving section receives information designating the number of subcarriers.

The serial-to-parallel converter converts the received signal into a signal having the number of subcarriers, and outputs the signal.

The inverse Fourier transform unit performs an inverse Fourier transform on the signal output after serial-parallel conversion, and outputs a signal of the number of subcarriers.

The parallel-to-serial conversion unit outputs a signal obtained by performing a parallel-to-serial conversion on the signal output after the inverse Fourier transform.

The transmitting section transmits the signal output after the parallel-to-serial conversion.

Further, the transmitting apparatus of the present invention can be configured to further include a selecting unit and an information transmitting unit instead of the information receiving unit.

Here, the selection section selects the number of subcarriers.

The information transmitting section transmits information for specifying the number of subcarriers.

Further, the transmitting apparatus of the present invention can be configured to further include an input receiving unit instead of the selecting unit.

Here, the input receiving unit receives an input of the number of subcarriers.

Further, the information receiving unit of the transmitting apparatus of the present invention
The transmission unit may further be configured to receive information designating the number of slots and the slot number, and to time-division with the number of slots, and transmit a signal using the slot of the slot number.

Further, the transmitting apparatus of the present invention can be configured so as to further include a measuring unit, an acquiring unit, a selecting unit, and an information transmitting unit instead of the information receiving unit.

Here, the measuring section measures communication traffic.

The acquisition unit acquires the number of slots previously associated with the measured communication traffic and the slot number to be used.

The selector selects a value obtained by dividing a predetermined constant by the number of slots as the number of subcarriers.

The information transmitting unit transmits information designating the number of subcarriers, the number of slots, and the slot number.

The receiving apparatus according to the present invention is configured to include a receiving unit, an information receiving unit, a serial-to-parallel converter, a Fourier transformer, a parallel-serial converter, and an output unit.

Here, the receiving section receives the signal.

The information receiving section receives information designating the number of subcarriers.

The serial-to-parallel converter converts the received signal into a signal having the number of subcarriers, and outputs the signal.

The Fourier transform unit Fourier-transforms the signal output after serial-parallel conversion and outputs a signal of the number of subcarriers.

The parallel-to-serial conversion unit outputs a signal obtained by performing a parallel-to-serial conversion on the signal output after the Fourier transform.

The output unit outputs the signal output after the parallel-to-serial conversion as a transmitted signal.

Further, the receiving apparatus of the present invention can be configured to further include a selecting section and an information transmitting section in place of the information receiving section.

Here, the selection section selects the number of subcarriers.

The information transmitting section transmits information designating the number of subcarriers.

Further, the receiving apparatus of the present invention can be configured to further include an input receiving unit instead of the selecting unit.

The input receiving unit receives an input of the number of subcarriers.

The information receiving section of the receiving apparatus according to the present invention comprises:
The receiving unit may further be configured to receive information designating the number of slots and the slot number, and to receive the signal using the slot of the slot number by time-division with the number of slots.

Further, the receiving device of the present invention can be configured so as to further include a measuring unit, an acquiring unit, and an information transmitting unit instead of the information receiving unit.

Here, the measuring section measures communication traffic.

The acquisition unit acquires the number of slots previously associated with the measured communication traffic and the slot number to be used.

The information transmitting section transmits information for specifying the number of subcarriers, the number of slots, and the slot number.

The selecting method of the present invention is configured to include a selecting step and a transmitting step.

Here, in the selection step, the number of subcarriers for orthogonal frequency division multiplex transmission is selected.

In the transmitting step, information designating the selected number of subcarriers is transmitted to the transmitting device and the receiving device.

Further, the selection method of the present invention can be configured to further include an input receiving step.

Here, in the input receiving step, input of the number of subcarriers for orthogonal frequency division multiplex transmission is received.

In the selection step, the number of subcarriers whose input has been accepted is selected.

Further, the selection method of the present invention can be configured to further include a measurement step and an acquisition step.

Here, in the measuring step, communication traffic is measured.

In the obtaining step, the number of slots previously associated with the measured communication traffic and the slot number to be used are obtained.

In the selection step, a value obtained by dividing a predetermined constant by the obtained number of slots is selected as the number of subcarriers.

In the transmitting step, information for designating the number of slots and the slot number is transmitted.

In the transmission step of the selection method of the present invention,
The information can be configured to be transmitted wirelessly.

The transmitting method of the present invention is configured to include a signal receiving step, an information receiving step, a serial / parallel converting step, an inverse Fourier transform step, a parallel / serial converting step, and a transmitting step.

In the signal receiving step, a signal to be transmitted is received.

In the information receiving step, information specifying the number of subcarriers is received.

In the serial-to-parallel conversion step, the received signal is serial-to-parallel converted to a signal of the number of subcarriers and output.

In the inverse Fourier transform step, the signal output after serial-to-parallel conversion is subjected to inverse Fourier transform to output a signal of the number of subcarriers.

In the parallel-to-serial conversion step, a signal obtained by performing a parallel-to-serial conversion on the signal output after the inverse Fourier transform is output.

In the transmitting step, a signal output after being subjected to parallel-to-serial conversion is transmitted.

Further, the transmitting method of the present invention can be configured to further include a selecting step and an information transmitting step instead of the information receiving step.

Here, in the selection step, the number of subcarriers is selected.

In the information transmitting step, information for designating the number of subcarriers is transmitted.

Further, an input accepting step can be provided in place of the selecting step of the transmitting method of the present invention.

Here, in the input receiving step, input of the number of subcarriers is received.

In the information receiving step of the transmitting method of the present invention, information for designating the number of slots and the slot number is further received. It can be configured to transmit signals using slots.

[0107] Further, instead of the information receiving step of the transmitting method of the present invention, a configuration may be provided in which a measuring step, an obtaining step, a selecting step, and an information transmitting step are further provided.

Here, in the measuring step, communication traffic is measured.

In the obtaining step, the number of slots previously associated with the measured communication traffic and the slot number to be used are obtained.

In the selection step, a value obtained by dividing a predetermined constant by the number of slots is selected as the number of subcarriers.

In the information transmitting step, information for designating the number of subcarriers, the number of slots, and the slot number is transmitted.

The receiving method of the present invention comprises a receiving step, an information receiving step, a serial / parallel converting step, a Fourier transforming step,
It is configured to include a parallel-serial conversion step and an output step.

Here, in the receiving step, a signal is received.

In the information receiving step, information for designating the number of subcarriers is received.

In the serial-to-parallel conversion step, the received signal is serial-to-parallel converted to a signal of the number of subcarriers and output.

[0116] In the Fourier transform step, the signal output after serial-parallel conversion is subjected to Fourier transform to output a signal of the number of subcarriers.

In the parallel-to-serial conversion step, a signal obtained by performing a parallel-to-serial conversion on the signal output after the Fourier transform is output.

In the output step, the signal output after the parallel-to-serial conversion is output as a transmitted signal.

In addition, the receiving method of the present invention may be configured to further include a selecting step and an information transmitting step instead of the information receiving step.

Here, in the selection step, the number of subcarriers is selected.

In the information transmitting step, information for specifying the number of subcarriers is transmitted.

Further, an input accepting step may be further provided in place of the receiving method selecting step of the present invention.

In the input receiving step, an input of the number of subcarriers is received.

Further, in the information receiving step of the receiving method of the present invention, information for specifying the number of slots and the slot number is further received. It can be configured to receive signals using slots.

Further, the receiving method of the present invention may be configured to further include a measuring step, an acquiring step, and an information transmitting step, instead of the information receiving step.

Here, the measuring step measures communication traffic.

In the obtaining step, the number of slots previously associated with the measured communication traffic and the slot number to be used are obtained.

In the information transmitting step, the number of the subcarriers and
The information for specifying the number of slots and the slot number is transmitted.

The communication system, the selecting device, the transmitting device, the receiving device, the selecting method, the transmitting method, and the program for realizing the receiving method of the present invention are stored in a compact disk, a floppy disk, a hard disk, a magneto-optical disk, a digital video disk, a magnetic disk. It can be recorded on a computer-readable information recording medium such as a tape or a semiconductor memory.

The program recorded on the information recording medium of the present invention can be stored in a general-purpose computer having a storage device, a computing device, an output device, a communication device, etc., a mobile phone, a PHS device,
The selection device described above, which is executed by a mobile terminal such as a game device, an information processing device such as a parallel computer and the like to function as a selection device, a transmission device, and a reception device.
A transmission device, a reception device, a selection method, a transmission method, and a reception method can be realized.

In particular, the DSP of software radio terminals
(Digital Signal Processor) and FPGA (Field Pr
By loading a program recorded on the information recording medium of the present invention into an ogrammable gate array) section and configuring and operating a circuit corresponding to the program, or executing a process corresponding to the program, the above-described selection is performed. Device, transmitting device,
A receiving device, a selecting method, a transmitting method, and a receiving method can be realized.

Further, an information recording medium on which the program of the present invention is recorded can be distributed and sold independently of the portable terminal and the information processing device.

[0133]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. The embodiments described below are for explanation, and do not limit the scope of the present invention. Therefore, those skilled in the art can adopt embodiments in which each of these elements or all elements are replaced with equivalents, but these embodiments are also included in the scope of the present invention.

[0134] For the above-described pre-processing and post-processing, known techniques can be used, and therefore, description thereof will be omitted below.

(Embodiment of Communication System) FIG. 3 is a schematic diagram showing a schematic configuration of the first embodiment of the communication system of the present invention. Hereinafter, description will be made with reference to FIG.

The communication system 101 includes the selecting device 201
, A transmitting device 301 and a receiving device 401.

Selector 201 selects the number of subcarriers in the OFDM transmission system, and transmits information designating this to transmitter 301 and receiver 401.

The transmitting apparatus 301 receives the signal to be transmitted, receives the information specifying the number of subcarriers transmitted from the selecting apparatus 201, and processes the signal to be transmitted by the OFDM transmission method of the number of subcarriers. And send.

Receiving apparatus 401 receives the signal transmitted from transmitting apparatus 301, receives information designating the number of subcarriers, and receives the OFDM signal of the number of subcarriers.
The signal received by the transmission method is processed to obtain the transmitted signal.

FIGS. 4 to 6 show the selection device 201, the transmission device 301, and the reception device 401 of the communication system 101.
It is explanatory drawing which shows the example of a structure of. Hereinafter, FIGS. 4 to 6
This will be described with reference to FIG.

In the configuration examples shown in FIGS. 4 to 6, the selecting device 201 of the communication system 101, the transmitting device 301, and the receiving device 401 are connected to the transmitting device 391 and the receiving device 4 respectively.
It is arranged inside 91.

The transmitting device 391 and the receiving device 491
It may be configured as a mobile terminal or as a base station for mobile communication.

FIG. 4 shows a configuration in which the selecting device 201 and the transmitting device 301 are arranged in the transmitting device 391, and the receiving device 401 is arranged in the receiving device 491.

The selection device 201 in the transmitting device 391,
The transmitting device 301 communicates information specifying the number of subcarriers by wire. On the other hand, the selecting device 201 in the transmitting device 391, the receiving device 401 in the receiving device 491,
Communicates information specifying the number of subcarriers wirelessly.

FIG. 5 shows that the transmitting device 301 is disposed in the transmitting device 391 and the selecting device 2 is disposed in the receiving device 491.
01 and the receiving device 401 are shown.

The selecting device 201 in the receiving device 491,
The receiving device 401 communicates information specifying the number of subcarriers by wire. On the other hand, the transmitting device 301 in the transmitting device 391, the selecting device 201 in the receiving device 491,
Communicates information specifying the number of subcarriers wirelessly.

FIG. 6 shows a configuration in which the selecting device 201 is divided into a selecting device A unit 201a and a selecting device B unit 201b, and each is arranged in a transmitting device 391 and a receiving device 491. Show.

A selection device A section 201a in the selection device 201
Transmission of information between the communication device and the selection device B unit 201b is performed wirelessly. The selection device 201 and the transmission device 301 in the transmission-side device 391 communicate information specifying the number of subcarriers by wire. The selecting device 201 and the receiving device 401 in the receiving device 491 communicate information specifying the number of subcarriers by wire.

(Embodiment of Selection Device) FIG. 7 is a schematic diagram showing a schematic configuration of a first embodiment of the selection device of the present invention. Hereinafter, description will be made with reference to FIG. Note that the same reference numerals are given to the same elements as those shown in the above-described drawings.

The selection section 501 of the selection device 201 selects the number of subcarriers. Information transmitting section 502 transmits information designating the selected number of subcarriers to transmitting apparatus 301 and receiving apparatus 401.

As described above, when the selecting device 201 is formed integrally with the transmitting device 301 or the receiving device 401, the transmitting device 301 and the receiving device 401 are connected to the integrally formed side. Information specifying the number of subcarriers is transmitted by wire, and information specifying the number of subcarriers is transmitted wirelessly to the other.

When information specifying the number of subcarriers is transmitted by radio, a communication device such as an antenna used for transmitting a signal to be transmitted by the OFDM transmission method is shared with the transmission device 301 and the reception device 401. be able to.

As described above, the number of subcarriers can be dynamically selected by the selector 201. The number of dynamically selected subcarriers is determined by the transmitting device 301 as described later.
And the receiving device 401, so that the number of subcarriers of the OFDM transmission scheme between them can be dynamically changed as necessary.

The range of selection of the number of subcarriers can be changed according to the communication quality required between the transmitting apparatus 301 and the receiving apparatus 401 and the characteristics of the radio wave propagation environment in which the communication system is placed. it can.

(Embodiment of Transmitting Apparatus) FIG. 8 is a schematic diagram showing a schematic configuration of an embodiment of the transmitting apparatus of the present invention.
Hereinafter, description will be made with reference to FIG. Note that the same reference numerals are given to the same elements as those shown in the above-described drawings.

[0156] Signal receiving section 601 of transmitting apparatus 301 receives a signal to be transmitted. The signal to be transmitted may be a digital signal or an analog signal. The received signal is subjected to the same preprocessing as that employed in the conventional OFDM transmission system.

On the other hand, the information receiving section 602
The information specifying the number of subcarriers transmitted from 1 is received. Since the number of subcarriers can be dynamically changed, OFDM for dynamically changing the number of subcarriers
Transmission becomes possible.

The serial / parallel converter 603 converts the signal received by the signal receiver 601 from serial to parallel in accordance with the number of subcarriers, and outputs a plurality of signals. The number of the plurality of signals is the number of the subcarriers.

The inverse Fourier transform unit 604 treats the plurality of signals as a distribution of orthogonal frequencies, and outputs a plurality of signals representing a time series of signals corresponding to the frequency distribution.
The number of input signals and output signals of the inverse Fourier transform unit 604 also changes according to the number of subcarriers.

The parallel-to-serial conversion unit 605 performs parallel-to-serial conversion on a plurality of output signals subjected to inverse Fourier transform, and outputs a single signal. Similarly, the number of input signals of the parallel-to-serial conversion unit 605 also changes according to the number of subcarriers.

The single signal output from parallel-to-serial conversion section 605 is appropriately digital-to-analog converted in transmission section 606 in the same manner as a conventional transmission apparatus of the OFDM transmission system, and is up-converted to reception apparatus 401. Sent.

As described above, the number of signals to be processed by the serial / parallel converter 603, the inverse Fourier transformer 604, and the parallel / serial converter 605 is governed by the number of subcarriers specified by the information received by the information receiver 602. , This number changes dynamically.

Therefore, the serial / parallel converter 603, the inverse Fourier transformer 604, and the parallel / serial converter 605 change the operation by receiving the number of subcarriers as a parameter.
Other common modules can have a software radio configuration as already configured.

Further, an embodiment may be adopted in which a DSP or an FPGA is used, and the circuit configuration is changed every time the number of subcarriers is changed.

An embodiment in which a high-speed CPU (Central Processing Unit) executes the processing performed by the serial-parallel conversion unit 603, the inverse Fourier conversion unit 604, and the parallel-serial conversion unit 605 by digital processing is adopted. Can also.

(Embodiment of Receiving Apparatus) FIG. 9 is a schematic diagram showing a schematic configuration of an embodiment of the receiving apparatus of the present invention.
Hereinafter, description will be made with reference to FIG. Note that the same reference numerals are given to the same elements as those shown in the above-described drawings.

The receiving section 701 of the receiving device 401 receives the signal transmitted by the transmitting device 301. The receiving unit 70
1, as in the conventional OFDM transmission system receiving apparatus,
The received signal is down-converted and sampled at appropriate intervals to perform analog-to-digital conversion.

[0168] Information receiving section 702 receives information specifying the number of subcarriers transmitted from selecting apparatus 201.
Since the number of subcarriers can be dynamically changed to the same value as that of the transmitting device 301, OFDM transmission in which the number of subcarriers is dynamically changed becomes possible.

The serial / parallel converter 703 converts the signal received by the receiver 701 from serial to parallel according to the number of subcarriers, and outputs a plurality of signals. The number of the plurality of signals is the number of the subcarriers.

The Fourier transform section 704 treats the plurality of signals as a time series of signals, and outputs a plurality of signals representing the distribution of orthogonal frequencies corresponding to the plurality of signals. Fourier transform unit 7
The number of input signals and output signals of 04 also changes according to the number of subcarriers. Thus, the transmitting device 30
In step 1, the converted signal is inversely converted.

The parallel-to-serial conversion unit 705 performs a parallel-to-serial conversion on a plurality of output signals after the Fourier transform, and outputs a single signal. Similarly, the number of input signals of the parallel-to-serial conversion unit 705 also changes according to the number of subcarriers.

The single signal output from parallel-to-serial conversion section 705 is subjected to the same processing as post-processing executed by the conventional OFDM transmission type receiving apparatus at output section 706 to convert the transmitted signal. Output.

As described above, the number of signals processed by the serial / parallel converter 703, the Fourier transformer 704, and the parallel / serial converter 705 is governed by the number of subcarriers specified by the information received by the information receiver 702. This number changes dynamically. However, the number of the subcarriers is
Has the same value as

Therefore, the serial / parallel converter 703, the Fourier transformer 704, and the parallel / serial converter 705 change the operation by accepting the number of subcarriers as a parameter, and the other common modules are already configured and set. , A software radio system can be adopted.

Further, an embodiment may be adopted in which a DSP or FPGA is used, and the circuit configuration is changed every time the number of subcarriers is changed.

Further, an embodiment in which the processing performed by the serial / parallel converter 703, the Fourier transformer 704, and the parallel / serial converter 705 are executed by a high-speed CPU by digital processing may be adopted.

(Second Embodiment) The configuration of the second embodiment is almost the same as that of the above embodiment, but the configuration of the selection device is different. This will be described below.

FIG. 10 is a schematic diagram showing a schematic configuration of a second embodiment of the selection device of the present invention. Hereinafter, description will be made with reference to FIG. Note that the same reference numerals are given to the same elements as those shown in the above-described drawings.

The input receiving unit 801 of the selecting device 201 receives an input of the number of subcarriers from a user or another control device. Selection section 501 selects the number of accepted subcarriers. Information transmitting section 502 transmits information designating the selected number of subcarriers to transmitting apparatus 301 and receiving apparatus 401.

When the input receiving unit 801 is formed integrally with the transmitting device 391, for example, the transmitting user operates buttons, switches, dials, and the like prepared for the transmitting device 391 during a call. This allows the quality of the call to be raised or lowered as needed. When the transmitting device 391 is connected to any control device, the number of subcarriers can be dynamically changed according to an instruction from the control device. The same applies to the case where the input receiving unit 801 is configured integrally with the receiving-side device 491.

In this embodiment, for example, the call quality can be dynamically changed at the request of the user.
A communication system of the OFDM transmission system can be realized.

(Third Embodiment) The third embodiment is a preferred embodiment to be used together with the cellular communication. Hereinafter, description will be made with reference to the drawings.

FIG. 11 is an explanatory diagram showing a cell of the cellular system and the setting of a communication channel used in the cell.

In the service area, base stations are arranged at such a distance that the interference wave is sufficiently attenuated. The base station includes a transmitting device and a receiving device for communicating with a portable terminal owned by a user in the cell. The user's mobile terminal includes a corresponding receiving device and transmitting device.

If the radio wave propagation characteristics are the same, each cell is Voronoi-divided using the position of the base station as a base point. In the example shown in FIG. 11, each cell is hexagonal.

In reality, since the radio wave propagation characteristics differ depending on the position, the cell is divided into cells having different shapes.

Now, in order to prevent interference between base stations of such a cell, a plurality of communication channels are prepared, and adjacent cells are set to use different communication channels. In the example shown in FIG. 11, four channels A, B, C, and D are used.

In a distant cell, communication is performed using the same channel. However, since interference is sufficiently attenuated by distance,
Channels can be reused to save frequency resources.

FIG. 12 shows the relationship between the distribution of users in each cell and communication traffic in such a cellular communication system.

In the explanatory diagram shown in FIG. 12, seven users numbered 1 to 7 are distributed. In the present embodiment, when there is a user in an adjacent cell, the traffic is classified as high traffic, and when there is no user, the traffic is classified as low traffic.
Note that other classifications can also be adopted, and the present embodiment is also included in the scope of the present invention.

In this embodiment in which the cellular system and the OFDM transmission system of the present invention are used together, interference between users is suppressed by time division multiplex transmission under high traffic, while a communication channel is provided to the user under low traffic. It occupies and performs large-capacity transmission.

FIG. 13 is an explanatory diagram showing a schematic configuration of the selection device of the present embodiment. Hereinafter, description will be made with reference to FIG. Note that the same reference numerals are given to the same elements as those shown in the above-described drawings.

[0193] Measuring section 1101 of selecting apparatus 201 measures communication traffic. As described above, in the present embodiment, measurement is performed in two stages, such as high traffic when there is a user in an adjacent cell and low traffic when there is no user. In this case, the user information set in each mobile terminal is used.

The obtaining unit 1102 obtains the number of slots previously associated with the measured communication traffic and the slot number to be used. In this embodiment,
High traffic is associated with four slots, and low traffic is associated with one slot.

Also, under high traffic, different slot numbers are assigned to different users.

The selecting section 501 selects a value obtained by dividing a predetermined value by the acquired number of slots as the number of subcarriers. Therefore, in the present embodiment, under high traffic, a quarter number of subcarriers under low traffic is selected.

Information transmitting section 502 transmits information for specifying the number of selected subcarriers, information for specifying the acquired number of slots and slot number, to transmitting apparatus 30.
1 and to the receiving device 401.

FIG. 14 is an explanatory diagram showing the relationship between the number of subcarriers and frames under low traffic and high traffic.

Under high traffic, the number of used subcarriers is one fourth of the maximum (low traffic), and the transmission speed is also one fourth. For this reason, an original transmission frame (equal to a four-slot time length) is time-divided into four slots, a slot having the acquired slot number is selected, and this is set as one frame, and the user (transmitting device 301 The transmission is performed by using the pair of the receiving device 401 and the receiving device 401).

Note that the selection of the slot number to be used is as follows.
For example, the selection may be made at random, or an appropriate algorithm may be separately prepared.

Using the number of slots and the slot number for the time division device obtained by the selection device 201, the transmission device 3
01 of the receiving device 401 and the transmitting unit 606 of the receiving device 401
And perform communication in a time sharing manner.

FIG. 15 is an explanatory diagram showing a state of a signal frame used for transmission and reception by each user in the case of the user distribution shown in FIG. Since the users 1 and 2 are under low traffic, the former performs communication using the maximum number of subcarriers.

[0203] Since the users 3 to 7 are under high traffic, each uses a quarter number of subcarriers and selects a communication slot to reduce interference. For example, user 3 and user 4 communicate in different slots because they are in a densely populated area. As a result, it is possible to reduce deterioration of transmission characteristics due to mutual interference.

The other structure of this embodiment is the same as that of the above embodiment.

(Fourth Embodiment) The fourth embodiment is almost the same as the third embodiment, except that the measurement unit 1101 and the acquisition unit 1102 of the selection device 201 make more sophisticated judgments and The difference is that the number and slot number are obtained.

That is, since there is a correlation between the interference between users when the number of subcarriers is set and the transmission quality, by appropriately controlling these, the QOS of the entire system can be improved.
(Quality Of Service; service quality), that is, transmission quality and transmission capacity are dynamically controlled. For this control, an algorithm more sophisticated than that of the third embodiment is used.

For example, an optimization algorithm for quantifying the QOS that can be received by each user in the communication system and changing the number of slots to be used by each user so as to maximize the total is adopted. Can be.

(Fifth Embodiment) In the above embodiment, the input receiving unit 601 of the transmitting device 301 performs a process corresponding to the conventional preprocessing, and the output unit 706 of the receiving device 401 outputs
Processes corresponding to conventional post-processes are performed, but the locations where these processes are performed can be changed as appropriate. For example, a process corresponding to the pre-processing may be performed after the serial-parallel conversion unit 603 performs the serial-parallel conversion. Parallel / serial conversion unit 705
May perform a process corresponding to post-processing before performing parallel-to-serial conversion. These embodiments are also included in the scope of the present invention.

[0209]

As described above, according to the present invention,
Communication system suitable for selecting the number of subcarriers of the OFDM transmission system as required, a selection device, a transmission device, a reception device, a selection method, a transmission method, a reception method, and information recording a program for realizing these A recording medium can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a conventional communication system of the OFDM transmission system.

FIG. 2 is an explanatory diagram showing a state of a frequency spectrum of an OFDM transmission system.

FIG. 3 is a schematic diagram illustrating a schematic configuration of an embodiment of a communication system according to the present invention.

FIG. 4 is a schematic diagram showing various configuration examples of each element of the communication system of the present invention.

FIG. 5 is a schematic diagram showing various configuration examples of each element of the communication system of the present invention.

FIG. 6 is a schematic diagram showing various configuration examples of each element of the communication system of the present invention.

FIG. 7 is a schematic diagram illustrating a schematic configuration of an embodiment of a selection device of the present invention.

FIG. 8 is a schematic diagram illustrating a schematic configuration of an embodiment of a transmission device of the present invention.

FIG. 9 is a schematic diagram illustrating a schematic configuration of an embodiment of a receiving device of the present invention.

FIG. 10 is a schematic diagram showing a schematic configuration of a second embodiment of the selection device of the present invention.

FIG. 11 is an explanatory diagram showing a cell of a cellular system and setting of a communication channel used in the cell.

FIG. 12 is an explanatory diagram showing the relationship between the distribution of users in each cell of the cellular system and communication traffic.

FIG. 13 is a schematic diagram showing a schematic configuration of a second embodiment of the selection device of the present invention.

FIG. 14 is an explanatory diagram showing the relationship between the number of subcarriers and frames under low traffic and high traffic.

FIG. 15 is an explanatory diagram showing a state of a signal frame used by each user for transmission and reception.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 conventional communication system 21 conventional transmission device 22 preprocessing unit 23 serial-parallel conversion unit 24 inverse Fourier conversion unit 25 parallel-serial conversion unit 26 transmission unit 31 conventional reception device 32 reception unit 33 serial-parallel conversion unit 34 Fourier conversion unit 35 Parallel / serial conversion unit 36 Post-processing unit 101 Communication system 201 Selection device 301 Transmission device 391 Transmission device 401 Receiving device 491 Receiving device 501 Selection unit 502 Information transmission unit 601 Signal reception unit 602 Information reception unit 603 Serial / parallel conversion unit 604 Reverse Fourier transform unit 605 Parallel / serial converter 606 Transmitter 701 Receiver 702 Information receiver 703 Serial / parallel converter 704 Fourier transformer 705 Parallel / serial converter 706 Output unit 801 Input receiving unit 1101 Measurement unit 1102 Acquisition unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayuki Fujise 3-4 Hikarinooka, Yokosuka-shi, Kanagawa F-term in the Yokosuka Wireless Communication Research Center, Ministry of Posts and Telecommunications, 5K022 DD01 DD17 DD23 DD33 FF01 5K028 AA11 BB06 CC02 CC05 DD01 DD02 HH02 LL02 LL11 MM12 PP11 SS06 SS16 SS24 TT02 5K067 AA13 BB02 CC04 EE71 GG03 GG11 HH23

Claims (49)

[Claims] 1. A communication system comprising a selection device, a transmission device, and a reception device, wherein: (a) the selection device selects the number of subcarriers for orthogonal frequency division multiplexing transmission; Transmitting information specifying the number of subcarriers to the transmitting device and the receiving device; (b) the transmitting device receives a signal to be transmitted, and specifies the number of subcarriers transmitted from the selecting device; Receiving the information, converting the received signal into a signal having the number of subcarriers in a serial-to-parallel manner and outputting the signal, and performing the inverse Fourier transform on the signal output after the serial-to-parallel conversion and performing a signal in the number of the subcarriers (C) outputting a signal obtained by performing parallel-to-serial conversion on the signal output by performing the inverse Fourier transform, and transmitting the signal output by performing the parallel-to-serial conversion to the receiving device; The receiving device receives a signal transmitted from the transmitting device, receives information specifying the number of subcarriers transmitted from the selecting device, and serially and parallelly receives the received signal with a signal of the number of subcarriers. Convert and output, output the serial-to-parallel converted signal, output the signal of the number of subcarriers by performing Fourier transform, output the signal obtained by performing the parallel-to-serial conversion of the Fourier-transformed signal, and output the signal. A communication system, wherein the signal output after the parallel-to-serial conversion is output as a transmitted signal. 2. The selection device further receives an input of the number of subcarriers for orthogonal frequency division multiplex transmission, and selects the number of subcarriers whose input has been received as the number of subcarriers specified by the transmitted information. The communication system according to claim 1, wherein the communication is performed. 3. The selection device further measures communication traffic, acquires the number of slots previously associated with the measured communication traffic and the slot number to be used, and obtains a predetermined number based on the number of slots. Is selected as the number of subcarriers specified by the transmitted information, and the transmitted information further specifies the number of slots and the slot number. Further, time-division is performed on the number of slots specified by the information transmitted from the selection device, and a signal is transmitted to the reception device using a slot having a slot number specified by the information. The time division by the number of slots specified by the information transmitted from the selection device, and the slot of the slot number specified by the information. Communication system according to claim 1, characterized in that receiving a signal from the transmission device using. 4. The selecting device is configured integrally with the transmitting device, the selecting device transmits the information to the transmitting device by wire, and the selecting device wirelessly transmits the information to the receiving device. The communication system according to any one of claims 1 to 3, wherein the transmitting device transmits the signal to the receiving device wirelessly. 5. The selecting device is configured integrally with the receiving device, the selecting device transmits the information to the receiving device by wire, and the selecting device transmits the information to the transmitting device. The communication system according to any one of claims 1 to 3, wherein the signal is transmitted wirelessly, and the transmitting device wirelessly transmits the signal to the receiving device. 6. The transmitting device transmits the information to the transmitting device and the receiving device wirelessly, and the transmitting device wirelessly transmits the signal to the receiving device. The communication system according to any one of claims 1 to 3, wherein 7. A selecting unit for selecting the number of subcarriers for orthogonal frequency division multiplexing transmission, and a transmitting unit for transmitting information designating the selected number of subcarriers to a transmitting device and a receiving device. A selection device, characterized in that: 8. An input receiving unit for receiving an input of the number of subcarriers for orthogonal frequency division multiplexing transmission, wherein the selecting unit selects the number of subcarriers whose input has been received. 8. The selection device according to 7. 9. The communication device according to claim 1, further comprising: a measuring unit configured to measure communication traffic; and an acquiring unit configured to acquire a number of slots previously associated with the measured communication traffic and a slot number to be used. The unit selects a value obtained by dividing a predetermined constant by the obtained number of slots as the number of subcarriers, and the transmitting unit transmits information specifying the number of slots and a slot number. The selection device according to claim 7, wherein: 10. The selecting device according to claim 7, wherein the transmitting unit transmits the information wirelessly. 11. A signal receiving unit for receiving a signal to be transmitted, an information receiving unit for receiving information designating the number of subcarriers, and converting the received signal into a signal of the number of subcarriers in parallel. A serial-to-parallel conversion unit to output; an inverse Fourier transform unit to perform an inverse Fourier transform on the output signal after the serial-to-parallel conversion to output a signal of the number of subcarriers; a signal output after the inverse Fourier transform A transmission device comprising: a parallel-to-serial conversion unit that outputs a signal obtained by performing parallel-to-serial conversion; and a transmission unit that transmits the signal that is output after being subjected to the parallel-to-serial conversion. 12. The information processing apparatus according to claim 11, further comprising: a selection unit that selects the number of subcarriers; and an information transmission unit that transmits information that specifies the number of subcarriers, instead of the information reception unit. The transmitting device according to claim 1. 13. The transmitting apparatus according to claim 12, further comprising: an input receiving unit that receives an input of the number of subcarriers, instead of said selecting unit. 14. The information receiving section further receives information designating the number of slots and the slot number, and the transmitting section performs time division by the number of slots and uses the slot of the slot number. The transmitting device according to claim 11, wherein the transmitting device transmits a signal. 15. A measuring unit for measuring communication traffic instead of the information receiving unit, and an acquiring unit for acquiring a number of slots previously associated with the measured communication traffic and a slot number to be used. A selection unit that selects a value obtained by dividing a predetermined constant by the number of slots as the number of subcarriers; and an information transmission unit that transmits information specifying the number of subcarriers, the number of slots, and the slot number. The transmitting device according to claim 14, further comprising: 16. A receiving unit for receiving a signal, an information receiving unit for receiving information designating the number of subcarriers, and a serial / parallel converter for converting the received signal into a signal having the number of subcarriers and outputting the signal. A parallel conversion unit, a Fourier transform unit that Fourier-transforms the serial-to-parallel output signal and outputs a signal of the number of subcarriers, and a parallel-serial conversion of the Fourier-transformed signal. A receiving apparatus comprising: a parallel-to-serial conversion unit that outputs a signal; and an output unit that outputs the parallel-to-serial converted signal output as a transmitted signal. 17. The information processing apparatus according to claim 16, further comprising: a selection unit that selects the number of subcarriers; and an information transmission unit that transmits information that specifies the number of subcarriers, instead of the information reception unit. 3. The receiving device according to claim 1. 18. The receiving apparatus according to claim 17, further comprising: an input receiving unit that receives an input of the number of subcarriers, instead of said selecting unit. 19. The information receiving section further receives information designating the number of slots and the slot number, and the receiving section performs time division on the number of slots and uses the slot of the slot number. The receiving device according to claim 16, wherein the receiving device receives a signal. 20. A measuring unit for measuring communication traffic instead of the information receiving unit, and an acquiring unit for acquiring a number of slots previously associated with the measured communication traffic and a slot number to be used. 20. The receiving apparatus according to claim 19, further comprising: an information transmitting unit configured to transmit information designating the number of subcarriers, the number of slots, and the slot number. 21. A selecting step of selecting the number of subcarriers for orthogonal frequency division multiplexing transmission, and a transmitting step of transmitting information designating the selected number of subcarriers to a transmitting device and a receiving device. A selection method characterized in that: 22. An input receiving step for receiving an input of the number of subcarriers for orthogonal frequency division multiplexing transmission, wherein the selecting step selects the number of subcarriers for which the input has been received. 22. The selection method according to 21. 23. The method according to claim 23, further comprising: a measuring step of measuring communication traffic; and an acquiring step of acquiring a number of slots previously associated with the measured communication traffic and a slot number to be used. In the step, a value obtained by dividing a predetermined constant by the obtained number of slots is selected as the number of subcarriers, and the transmitting step includes the number of slots, a slot number,
22. The information for designating a password is transmitted.
Selection method described in. 24. The selecting method according to claim 21, wherein said transmitting step transmits the information by radio. 25. A signal receiving step of receiving a signal to be transmitted, an information receiving step of receiving information designating the number of subcarriers, and serially / parallel converting the received signal into a signal of the number of subcarriers. A serial-to-parallel conversion step for outputting; an inverse Fourier transform step for performing an inverse Fourier transform on the signal output after the serial-to-parallel conversion to output a signal of the number of subcarriers; a signal output after the inverse Fourier transform A transmission method comprising: a parallel-to-serial conversion step of outputting a parallel-to-serial converted signal; and a transmission step of transmitting the parallel-to-serial converted and output signal. 26. The method according to claim 25, further comprising, in place of the information receiving step, a selecting step of selecting the number of subcarriers, and an information transmitting step of transmitting information designating the number of subcarriers. Transmission method described in. 27. The transmission method according to claim 26, further comprising: an input receiving step of receiving an input of the number of subcarriers in place of said selecting step. 28. The information receiving step further receives information designating the number of slots and the slot number, and the transmitting step performs time division on the number of slots and uses the slot of the slot number. The transmission method according to claim 25, wherein the signal is transmitted. 29. A measuring step of measuring communication traffic in place of the information receiving step, and an acquiring step of acquiring a number of slots previously associated with the measured communication traffic and a slot number to be used. A selecting step of selecting a value obtained by dividing a predetermined constant by the number of slots as the number of subcarriers; and an information transmitting step of transmitting information designating the number of subcarriers, the number of slots, and the slot number. The transmission method according to claim 28, further comprising: 30. A receiving step of receiving a signal, an information receiving step of receiving information designating the number of subcarriers, and a serial-to-parallel conversion of the received signal into a signal of the number of subcarriers and output. A parallel conversion step, a Fourier transformation step of Fourier-transforming the serial-to-parallel output signal and outputting a signal of the number of subcarriers, and a parallel-serial conversion of the Fourier-transformed signal. A receiving method, comprising: a parallel-serial conversion step of outputting a signal; and an output step of outputting the parallel-serial converted and output signal as a transmitted signal. 31. The method according to claim 30, further comprising a selecting step of selecting the number of subcarriers, and an information transmitting step of transmitting information designating the number of subcarriers, in place of the information receiving step. Receiving method described in. 32. The receiving method according to claim 31, further comprising: an input receiving step of receiving an input of the number of subcarriers in place of said selecting step. 33. The information receiving step further receives information designating the number of slots and the slot number, and the receiving step performs time division by the number of slots and uses the slot of the slot number. The receiving method according to claim 30, wherein the signal is received. 34. A measuring step of measuring communication traffic in place of the information receiving step, and an obtaining step of obtaining a number of slots previously associated with the measured communication traffic and a slot number to be used. The receiving method according to claim 33, further comprising: an information transmitting step of transmitting information designating the number of subcarriers, the number of slots, and the slot number. 35. A selection procedure for selecting the number of subcarriers for orthogonal frequency division multiplex transmission, and a transmission procedure for transmitting information designating the selected number of subcarriers to a transmission apparatus and a reception apparatus. A computer-readable information recording medium on which a program for realizing processing is recorded. 36. A receiving step for receiving an input of the number of subcarriers for orthogonal frequency division multiplexing transmission, wherein the selecting step selects the number of subcarriers whose input has been received. 36. The information recording medium according to claim 35, wherein: 37. The method according to claim 37, further comprising: a measurement procedure for measuring communication traffic; and an acquisition procedure for acquiring a number of slots previously associated with the measured communication traffic and a slot number to be used. The procedure selects a value obtained by dividing a predetermined constant by the obtained number of slots as the number of subcarriers. The transmitting procedure includes the number of slots, a slot number,
36. The information recording medium according to claim 35, wherein the information recording medium transmits a program for transmitting the information. 38. A program according to claim 35, wherein said transmitting step includes transmitting the information by radio.
38. The information recording medium according to any one of items 34 to 37. 39. A signal receiving procedure for receiving a signal to be transmitted, an information receiving procedure for receiving information designating the number of subcarriers, and a serial / parallel conversion of the received signal to a signal of the number of subcarriers. A serial-to-parallel conversion procedure to output; an inverse Fourier transform procedure to output the signal of the number of subcarriers by performing an inverse Fourier transform on the signal output after the serial-to-parallel conversion; and a signal output after the inverse Fourier transform. A computer-readable recording program for realizing a process including: a parallel-to-serial conversion procedure for outputting a parallel-to-serial converted signal; and a transmission procedure for transmitting the parallel-to-serial converted signal. Possible information recording medium. 40. A program recorded further comprising: a selection procedure for selecting the number of subcarriers; and an information transmission procedure for transmitting information designating the number of subcarriers, instead of the information reception procedure. 40. The information recording medium according to claim 39, wherein: 41. The information recording medium according to claim 40, further comprising: an input accepting step of accepting an input of the number of subcarriers, in place of said selecting step. 42. The information receiving procedure further receives information designating the number of slots and the slot number, and the transmitting procedure is time-divided by the number of slots and uses the slot of the slot number. 40. The information recording medium according to claim 39, wherein a program for transmitting a signal is recorded. 43. A measurement procedure for measuring communication traffic in place of the information receiving procedure, and an acquisition procedure for acquiring a number of slots previously associated with the measured communication traffic and a slot number to be used. And a selection procedure of selecting a value obtained by dividing a predetermined constant by the number of slots as the number of subcarriers; and an information transmission procedure of transmitting information designating the number of subcarriers, the number of slots, and the slot number. 43. The information recording medium according to claim 42, further comprising: recording a program. 44. A receiving procedure for receiving a signal, an information receiving procedure for receiving information designating the number of subcarriers, a serial-to-parallel conversion of the received signal to a signal of the number of subcarriers, and output. A parallel conversion procedure, a Fourier transform procedure of Fourier-transforming the serial-to-parallel output signal and outputting a signal of the number of subcarriers, and a parallel-serial transform of the Fourier-transformed signal. A computer-readable recording program for realizing a process including: a parallel-to-serial conversion procedure for outputting a signal; and an output procedure for outputting the parallel-to-serial converted and output signal as a transmitted signal. Information recording medium. 45. A program recorded further comprising: a selection procedure for selecting the number of subcarriers; and an information transmission procedure for transmitting information designating the number of subcarriers, instead of the information reception procedure. The information recording medium according to claim 44, wherein 46. The information recording medium according to claim 45, further comprising: an input receiving step of receiving an input of the number of subcarriers, in place of said selecting step. 47. The information receiving procedure further receives information designating the number of slots and the slot number, and the receiving procedure is time-divided by the number of slots and uses the slot of the slot number. 45. The information recording medium according to claim 44, wherein a program for receiving a signal is recorded. 48. A measurement procedure for measuring communication traffic instead of the information receiving procedure, and an acquisition procedure for acquiring a number of slots previously associated with the measured communication traffic and a slot number to be used. The information recording method according to claim 47, further comprising: an information transmission procedure for transmitting information designating the number of subcarriers, the number of slots, and the slot number. Medium. 49. The information recording medium according to claim 35, wherein the information recording medium is a compact disk, a floppy (registered trademark) disk, a hard disk, a magneto-optical disk, a digital video disk, a magnetic tape, or a semiconductor memory. An information recording medium according to claim 1.