JP2920131B1 - OFDM signal transmission device - Google Patents

Abstract

The present invention makes it possible to adaptively cope with interference with an OFDM signal and to effectively use a frequency, which is difficult in a conventional system. SOLUTION: OF transmitted from an OFDM transmitter 22 is provided.
The DM signal is received and demodulated by the OFDM receiver 23, and the interference wave detection circuit 236 reads the frequency spectrum of the interference wave in the null symbol period from the demodulated data.
Then, based on the interference wave information, the mapping circuit 22 of the OFDM transmitter 22 is mapped by the mapping control circuit 226.
The position of the carrier hole is adaptively changed by instructing the position of the carrier hole. If no interfering wave is detected, the signal is allocated to data transmission for communication use instead of the carrier hole.

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 (OFDM) transmission / reception system, and more particularly to an OFDM transmission / reception system for reducing interference for monitoring with other radio waves existing in an OFDM transmission band and effectively using the frequency. The present invention relates to a signal transmission device.

[0002]

2. Description of the Related Art Conventionally, a broadcasting system based on the OFDM system is said to be a system suitable for terrestrial digital television broadcasting or digital audio broadcasting. Inverse Fourier transform (I / O) is performed on transmission data as complex data on a frequency axis.
FFT) to convert it to a baseband signal on the time axis, and to transmit this after frequency conversion.

In recent years, research and development have been actively conducted to apply the OFDM system to terrestrial digital television broadcasting, and various proposals have been made. However, interference and interference with existing terrestrial analog television broadcasting and audio broadcasting have been proposed. Some technologies related to conversion have also been proposed.

For example, Japanese Unexamined Patent Publication No. 7-79415 discloses that the amplitude of the frequency component of an OFDM signal, which is attenuated by a Nyquist filter in an analog television receiver, is compatible with the analog television receiver and the OFDM receiver. There is disclosed a technique of transmitting the data in a larger size. Also,
JP-A-6-113272 discloses a technique of tracking the instantaneous frequency of an FM broadcast wave with a tracking filter and selecting an OFDM signal frequency to a frequency that does not interfere with analog FM broadcast. Further, Japanese Unexamined Patent Publication
No. 253,738 discloses that by using a comb filter, even channels that cannot be transmitted or received on a television are used.
A technology that enables transmission of a television broadcast by FDM is disclosed.

In the OFDM system, there is a technique called a carrier hole as a measure for reducing interference interference received by an OFDM signal from analog television broadcasting (May 1995).
Mon., published by Trikeps Co., Ltd., “Next-Generation Digital Modulation / Demodulation Technology”, pages 163 to 168).

[0006] The carrier hole utilizes the feature that the OFDM system can select not to use a specific carrier (carrier), and makes the spectrum part which is susceptible to interference from current analog television broadcasting unused. It is to do. A conventional example will be described below with reference to the drawings.

FIG. 6 is a block diagram of a conventional OFDM signal transmitting device, and FIG. 7 is a frequency spectrum diagram showing the operation of the device.

In FIG. 6, input data to be transmitted is input to a serial / parallel conversion circuit 11. The serial / parallel conversion circuit 11 rearranges input data from serial to parallel, and its parallel output is input to a mapping circuit 12. The mapping circuit 12 allocates a parallel input carrier frequency, amplitude and phase.

The output of the mapping circuit 12 is IFFT
The circuit 13 performs an inverse Fourier transform (IFFT) to generate a baseband signal on the time axis, and the frequency is converted to a high-frequency signal by the transmission circuit 14 and is subjected to processing such as unnecessary wave (spurious) removal and signal amplification. 15 is transmitted as a radio wave.

OFDM transmitted from transmission antenna 15
When the signal is viewed from the frequency axis direction, the frequency spectrum has a rectangular shape between the frequencies f4 and f5 as shown in FIG. For example, in the case of a 2k OFDM system, about 2,000 between f4 and f5 in FIG.
There will be a carrier for the book.

If there is a co-channel interference wave having a strong level of a specific frequency component indicated by f6 as shown in FIG. 7B, the OFDM signal in FIG.
The frequency component corresponding to No. 6 cannot be correctly demodulated due to the deterioration due to the interference, and the error rate increases, resulting in a large deterioration of the transmission signal quality.

In analog TV broadcast waves, in many cases,
The strong frequency specific frequency components corresponding to f6 in FIG. 7B include a video carrier, a color subcarrier, an audio carrier, and the like. Here, as shown in FIG. If not used, this interference can be avoided.

The above is the method of the carrier hole. The use or non-use of the specific frequency portion can be selected by setting the carrier frequency, amplitude and phase of each data of the mapping circuit 12 in FIG. It is. It is generally known that a carrier hole is fixedly provided in a portion of an analog television broadcast wave such as a video carrier, a color subcarrier, and an audio carrier.

However, as shown in FIG.
Further, if there is a co-channel interference wave having a strong level of a specific frequency component different from f7, the OFD
The M signal suffers from deterioration due to interference and cannot be demodulated correctly, so that the error rate increases and the transmission signal quality deteriorates significantly.

Research and development using the OFDM system has been rapidly prosperous in recent years, and a carrier hall has been proposed as a measure for coexistence with analog television broadcasting.
The interference that DM signals receive is not limited to analog television broadcasts. Various reception failures have been reported in the long history of current analog television broadcasting, and it is easily presumed from these cases that various interference problems also occur in digital television broadcasting based on the OFDM system.

[0016] On the other hand, the carrier hole is an effective means for avoiding interference, but since a specific frequency portion is not used, the data transmission efficiency naturally drops.

[0017]

As described above, in the conventional carrier hole method in the OFDM system,
The following problems exist.

First, since the position of the carrier hole is fixed, when interference other than analog television broadcasting is matched, the interference cannot be avoided at all.

Second, even when there is no interference,
Since the specific frequency portion is not used, the data transmission efficiency is reduced by that amount, and the frequency, which is a precious resource, cannot be effectively used.

Third, it is widely known that terrestrial interference is generally affected by various factors such as weather, season, and time zone. The approach cannot adapt adaptively to these constantly changing factors.

Here, an object of the present invention is to provide an OFDM signal transmitting apparatus capable of adaptively coping with interference with an OFDM signal, which is difficult in the conventional system, and enabling effective use of frequency.

[0022]

In order to achieve the above object, the present invention employs the following novel characteristic constitution means.

(1) A plurality of transmission data orthogonal to each other
Mapping processing means assigned to a carrier, and
Transmit multiple carriers to which data is assigned in the frequency domain
From the time domain to the OFDM (orthogonal frequency component
OFDM signal generation means for generating a signal (divided multiplexing).
Transmitting the OFDM signal generated by the means at a radio frequency
Transmitting means, and an OFDM signal transmitted by the transmitting means.
A monitoring OFDM receiving apparatus for receiving the OFDM signal;
An abnormality is detected in the OFDM transmission band from the received signal of the receiver.
Frequency component detected, and the signal level and frequency
Means for acquiring interference wave information as interference wave information, and the generation of the interference wave from the signal level of the information obtained by this means.
When life is recognized, the mapping processing means:
Transmit data to the carrier of the specific frequency part corresponding to that frequency.
Data is not allocated and the carrier is not transmitted.
And a mapping control means for forming a carrier hole .

(2) In the configuration of (1), the interference frequency information obtaining means transmits all carrier waves to the OFDM signal.
Null symbol period at which exit stops is at a known position
When the null signal is received from the received signal of the OFDM receiver,
Extract the signal of the symbol period and convert it to a frequency domain signal
However, if an abnormality is found in this frequency domain signal component,
The signal level and frequency as interference information.
Characterized in that that.

(3) In the configuration of ( 1 ), the OFD
The M receiving device can be located inside or near an external or remote location.
Receiving the OFDM signal,
Frequency at which abnormality is observed in the OFDM transmission band during the vol period
Detects several components and reports the signal level and frequency as interference information
And transmitted to the mapping control means.

[0026] In any one of the (4) (1) to (3), wherein the mapping control unit, the interference wave information
Are set in advance by associating
Finite number of carrier hoses
Memory circuit to store the combination pattern of
When the occurrence of an interference wave is recognized from the interference wave information
Corresponding to the interference wave information with reference to the memory circuit
To the mapping processing means,
To stop the carrier wave transmission corresponding to the specified pattern.
Characterized in that that.

[0027] In the configuration of any one of (5) (1) to (3), wherein the mapping control unit, the interference wave information
Are set in advance by associating
Combination pattern of finite number of carrier holes
A memory circuit for storing the
When the occurrence of an interference wave is recognized from the
Specify the pattern corresponding to the interference wave information by referring to the road
And the pattern specified for the mapping processing means.
And stop transmitting the carrier corresponding to
The mapping process is performed by using pattern information as transmission data.
The data is input to the stage and multiplexed with other transmission data .

(6) In any one of the constitutions (1) to (3) , the mapping control means may include the
The above-mentioned duplication is associated with each value assumed in advance.
For each segment, which is a group unit of a number of carriers,
A finite number of carrier hosts that are defined and known on the receiving side
Memory circuit that stores the combination pattern of rules
The occurrence of an interference wave is recognized from the interference wave information
When referring to the memory circuit,
Identify the corresponding segment pattern and use the mapping
Corresponds to the segment pattern specified for the processing means
The transmission of the carrier wave is stopped .

(7) In any one of the constitutions (1) to (3) , the mapping control means may include
The above-mentioned duplication is associated with each value assumed in advance.
For each segment, which is a group unit of a number of carriers,
A defined combination of a finite number of carrier holes
A memory circuit for storing the turn,
When the occurrence of interference is recognized from the information, the memory
Referring to the circuit, of the segment corresponding to the
A pattern is specified and the mapping
Transmission of a carrier corresponding to the specified segment pattern
Stop and pattern information of the specific segment
Into the mapping processing means as transmission data,
The transmission is multiplexed with other transmission data .

(8) In any one of the constitutions (1) to (7) , the mapping processing means includes the mapping system.
Control means for transmitting the transmission data of the carrier wave of the specific frequency portion.
When de-allocation is removed, a specific data
Data of the specific frequency part.
The wave is a carrier hole or the specific data
Creates information data indicating that the
And multiplex transmission with other transmission data .

(9) In the configuration of (8), the interference wave
The information acquisition means is configured to calculate the information from the received signal of the OFDM receiver.
Detects frequency components where abnormalities are observed in the OFDM transmission band.
And obtain the signal level and frequency as interference information
The above-mentioned mapping is repeated every unit time.
The control unit reviews the specific frequency portion where the transmission data is not allocated or the possibility of allocating the specific data according to the signal level and frequency of the interference wave information per unit time, and transmits corresponding to the interference wave generation portion. together to varying <br/> the carrier, linked to is characterized in that so as to change the information of a specific frequency portion of assigning a specific frequency portion or specific data not assign the transmission data.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a block circuit diagram showing the configuration of an embodiment of an OFDM signal transmitting apparatus according to the present invention. The OFDM signal transmission apparatus 21 shown in FIG. 1 is roughly divided into an OFDM transmitter 22 and a monitoring OFDM receiver 23. The OFDM transmitter 22 is connected to a transmission antenna 24, and the OFDM receiver 23 is connected to a reception antenna 25. Connected to.

A serial / parallel (S / P) conversion circuit 221, an IFFT circuit 223 in the OFDM transmitter 22,
The D / A conversion circuit 224, the transmission circuit 225, and the transmission antenna 24 have the same functional configuration and the like as those of the conventional example shown in FIG. Has a function of halting the transmission of the carrier wave without assigning the input data.

The mapping control circuit 226 stores a generation pattern indicating which specific frequency portion of the OFDM signal is to be unused, or that there is no unused portion and other input data (hereinafter, sub-input data) is allocated. A memory circuit (not shown) and an OFDM receiver 2
3 and outputs a mapping instruction signal to the mapping circuit 222 indicating which specific frequency part is unused or which sub input data is allocated without any unused part.

Upon receiving this instruction signal, the mapping circuit 222 assigns sub-input data with the specified specific frequency part unused or with no unused part. At this time, generation pattern information indicating an unused frequency portion or a sub-input data allocation portion is superimposed on the OFDM signal using a predetermined carrier.

The OFDM receiver 23 is the OFDM transmitter 2
The OFDM signal is received by the receiving antenna 25 and is tuned and frequency-converted by the receiving circuit 231 to return to a baseband signal on the time axis, and the A / D conversion circuit 232 After that, the FFT circuit 233 performs Fourier transform (FFT) to demodulate the data on the frequency axis. The demodulated data is input to a mapping circuit 234, a pattern information extraction circuit 235, and an interference wave detection circuit 236.

Here, the pattern information extraction circuit 235
Extract the generation pattern information indicating the unused frequency part or sub-input data allocation part from the demodulated data,
The information is output to the demapping circuit 234. The dematching circuit 234 extracts only the data of the corresponding frequency portion from the generated pattern information, and reproduces and outputs the transmission data as a monitor signal. Also, the interference wave detection circuit 23
6 reads the frequency spectrum of the interfering wave from the level and phase change of the demodulated data in each carrier including the null symbol period, and detects a frequency part which is degraded by being affected by the interfering wave. The detection result is O
It is supplied to the mapping control circuit 222 of the FDM transmitter 22.

In this embodiment, the OFDM receiver 23
Is installed inside the OFDM signal transmission device 21, but it may be installed in the vicinity outside or in a remote place where an interference state is to be monitored.

Here, a technique called a null symbol is used for the OFDM signal for synchronization. The null symbol is one symbol period in which all carriers are stopped for synchronization, but the FFT of the OFDM receiver 23
The circuit 233 performs the Fourier transform also in the null symbol period, and outputs the data on the frequency axis to the detection circuit 236.

The operation of the above configuration will be described below with reference to FIGS.

FIG. 2A is a frequency spectrum diagram of an OFDM signal output from the OFDM transmitter 23 in an initial state, where f1 is a temporary carrier hole. In the symbol period in this case, the data on the frequency axis of the output of the FFT circuit 223 also has such a form. On the other hand, the data on the frequency axis of the output of the FFT circuit 223 during the null symbol period is supposed to be essentially no signal because all the carriers are stopped. , As shown in FIG.
An interference wave is visible at the output of the T circuit 223. In the case of FIG. 2B, the interference signal frequencies f2 and f3 different from f1 are seen.

Therefore, the detection circuit 236 outputs the FF
The frequency spectrum of the interference wave in the null symbol period is detected from the T result, and the interference wave frequency information is transmitted to the mapping control circuit 226 as an interference detection signal. In the mapping control circuit 226, when the interference detection signal is input,
The corresponding mapping instruction signal is read from the memory circuit and output to the mapping circuit 222 to change the carrier hole.

As a result, the mapping circuit 222 changes the position of the carrier hole to the position of f2 and f3 as shown in FIG. In this way, interference is avoided.

In the mapping control circuit 226, a plurality of (not infinite) carrier hole positions are stored in a memory circuit provided in the mapping control circuit 226 in a manner corresponding to various interference frequency combination patterns. An appropriate pattern is selected according to the signal content of the interference detection signal, and an instruction is given to the mapping circuit 222.

At this time, as shown in FIG. 2C, the number of carrier holes in the mapping control circuit 226 may be two or more instead of one. Thereby, it is possible to cope with a complicated pattern of an interference frequency as long as it can be unused as a carrier hole. Figure 3 shows a pattern example
(A), (b), (c), and (d) show.

As described above, the reason for patterning the position of the carrier hole is that the transmission frequency pattern of the OFDM transmitter 22 changes when the position of the carrier hole changes, so that a plurality of unspecified OFDM receivers (not shown) use this OFDM receiver. This is for facilitating signal demodulation. In this case, if a plurality of limited carrier hole position information is registered in advance in the unspecified OFDM receiver, the receiving side reads the pattern information and compares and compares the information to determine which frequency portion is the carrier hole. It becomes possible to identify.

In order to make demodulation of this OFDM signal easier in a plurality of unspecified OFDM receivers,
The mapping circuit 222 allocates the generation pattern information area of the carrier hole position to the transmission OFDM signal and transmits the transmission. Thus, the plurality of unspecified OFDM receivers can know that the carrier hole position has changed by looking at the area and identifying the generation pattern information of the carrier hole position.

Next, the operation in the case where no interference exists will be described. In FIG. 4, (a) is a frequency spectrum diagram of an output signal from the OFDM transmitter 22 in the initial state as in FIG. 2 (a), and f1 is a temporary carrier hole. Also in this case, as long as no interference exists, the result of the FFT in the null symbol period is as shown in FIG.

The result is also transmitted to the mapping control circuit 226 as a disturbance detection signal. When recognizing that there is no interference, the mapping control circuit 226 instructs the mapping circuit 222 to allocate and transmit the sub-input data instead of the carrier hole. As a result, as shown by hatching in FIG. 4C, the sub-input data can be transmitted in the area scheduled as the carrier hole, and the frequency can be effectively used.

Since the sub-input data cannot be transmitted when a request for a carrier hole is generated, the sub-input data is allocated to a communication use such as a communication line for broadcast relay which does not always need to be transmitted. In addition, since the sub-input data is not required to be always received on the receiving side, FIG.
(A) carrier hole position of f1 or FIG. 2 (c)
It is also possible to place the transmitter at the carrier hole positions of f2 and f3 described above and always perform transmission.

Further, the operation of reviewing the carrier hole is not limited to one time, and the interference may be monitored at all times during the null symbol period every frame. Also, a unit time, for example, 1 minute, 5 minutes
Minutes, etc. can be repeated, so the weather, season,
It is possible to adaptively respond to constantly changing factors such as time zones.

When the OFDM receiver 23 is installed in a remote place where the monitoring of the interference state is required, a similar system can be constructed by setting the transmission line of the interference detection signal to a telephone line or an optical fiber. is there.

As described above, in the present invention, the interference frequency is detected using the null symbol period and the carrier hole position is adaptively changed. Therefore, the adaptive response to the interference interference to the OFDM signal and the frequency effective Available.

In the above embodiment, the generation pattern information representing a specific frequency to be a carrier hole is multiplexed on the OFDM signal and transmitted. However, as shown in FIG. 5, a plurality of OFDM signals (in FIG. n), the segment # not to be transmitted is OFDM
The signal may be multiplexed and transmitted. in this case,
In the OFDM receiver 23, a pattern information extraction circuit 235
Instead of reading the generated pattern information from the demodulated data, the segment # information may be read.

[0056]

As described above, according to the present invention, as a first point, the position of the carrier hole can be adaptively changed, so that even if there is interference other than analog television broadcasting, the interference can be reduced. It is possible to avoid.

Second, when there is no interference, a specific frequency portion can be used for data transmission for communication purposes without leaving it unused, so that a decrease in data transmission efficiency is reduced, and It can contribute to effective utilization.

Third, since it is possible to adaptively cope with various constantly changing factors such as weather, seasons, and time zones, it is possible to avoid interference more widely.

As a result, O which was difficult in the conventional method
It is possible to provide an OFDM signal transmitting apparatus that can adaptively cope with interference with an FDM signal and effectively use a frequency.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a configuration of an embodiment of an OFDM signal transmitting apparatus according to the present invention.

FIG. 2 is a frequency spectrum diagram for explaining an operation when interference occurs in the embodiment.

FIG. 3 is a diagram showing a pattern example of a carrier hole generation position registered in advance in the embodiment.

FIG. 4 is a frequency spectrum diagram for explaining an operation when no interference occurs in the embodiment.

FIG. 5 is a diagram illustrating a method of transmitting carrier hole generation position information based on the presence or absence of a segment in the embodiment.

FIG. 6 is a block circuit diagram showing a configuration of a conventional OFDM signal transmission device.

FIG. 7 is a frequency spectrum diagram for explaining the operation of the conventional OFDM signal transmitting apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Serial-parallel conversion circuit 12 ... Mapping circuit 13 ... IFFT circuit 14 ... D / A conversion circuit 15 ... Transmission antenna 21 ... OFDM signal transmission device 22 ... OFDM transmitter 23 ... OFDM receiver 24 ... Transmission antenna 25 ... Reception antenna 221 ... Serial / parallel conversion circuit 222 ... Mapping circuit 223 ... IFFT circuit 224 ... D / A conversion circuit 225 ... Transmission circuit 226 ... Mapping control circuit 231 ... Reception circuit 232 ... A / D conversion circuit 233 ... FFT circuit 234 ... Demapping circuit 235 … Pattern information extraction circuit 236… Interference wave detection circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04J 11/00

Claims (9)

(57) [Claims] A plurality of transports of transmission data orthogonal to each other.
Mapping processing means for allocating to a wave, and a plurality of carriers to which transmission data is allocated by this means.
By transforming from the frequency domain to the time domain, OFDM (direct
OFDM signal generator for generating (interfrequency division multiplexing) signal
Stage and transmit the OFDM signal generated by this means at radio frequency
Transmitting means, and monitoring for receiving an OFDM signal transmitted by the transmitting means.
OFDM receiving apparatus for receiving
Frequency at which an abnormality is recognized in the OFDM transmission band from the transmission signal
Detects several components and reports the signal level and frequency as interference information
Means for obtaining interference wave information obtained as a signal; and obtaining the interference wave information from the signal level of the information obtained by this means .
When occurrence is recognized, the mapping processing means
To the carrier of the specific frequency part corresponding to that frequency.
Do not assign transmission data and do not transmit the carrier
An OFDM signal transmitting apparatus, comprising: mapping control means for forming a carrier hole by controlling. 2. The apparatus according to claim 2, wherein
Null symbol period when transmission of all carriers stops in FDM signal
The OFDM receiver when the distance is at a known position
Extract the signal of the null symbol period from the received signal of
To a signal in the frequency domain.
When an abnormality is found in the minute, the signal level and frequency
2. The OFDM signal transmitting apparatus according to claim 1, wherein the OFDM signal transmitting apparatus acquires the information as interference wave information . 3. The OFDM receiver according to claim 1, wherein
The OFDM signal installed outside or in a remote location
And receives an OFDM transmission band during the null symbol period.
Frequency components that are abnormal within the
OFDM signal transmitting apparatus according to claim 1, wherein to obtain the bell and the frequency as the interference wave information is characterized in that so as to transmit to the mapping control unit. 4. The mapping control means according to claim 1, wherein
Corresponding to each assumed value of information in advance,
A finite number of carry that is predefined and known by the receiver
Memory for storing combination patterns of holes
Circuit, and the generation of an interference wave is recognized from the interference wave information.
The interference signal information by referring to the memory circuit.
A pattern corresponding to the mapping processing means
The transmission of the carrier corresponding to the specified pattern
4. The OFDM signal transmitting device according to claim 1, wherein the signal is stopped. Wherein said mapping control unit, the interference wave
Corresponding to each assumed value of information in advance,
Combination of a limited number of predefined carrier holes
A memory circuit for storing the interference pattern.
When occurrence of interference is recognized from the harmful wave information,
Pattern corresponding to the interference wave information with reference to the
To the mapping processing means.
Stop transmitting the carrier corresponding to the turn, and
The mapping as the transmission data using the specific pattern information
Input to the processing means and multiplexed with other transmission data
OFDM signal transmitting apparatus according to any one of claims 1 to 3, characterized in that that. 6. The mapping control means according to claim 1 , wherein
Carriers are grouped into segments by a predetermined number
When there is a
Predefined and known on the receiving side in association with each
A finite number of carrier holes in the segment unit
A memory circuit for storing combination patterns is provided.
If the occurrence of an interfering wave is recognized from the interfering wave information,
Corresponding to the interference wave information with reference to the memory circuit
The segment pattern to be mapped,
Corresponding to the segment pattern specified for
2. The method according to claim 1, wherein the transmission of the carrier is stopped.
4. The OFDM signal transmitting device according to any one of claims 1 to 3 . 7. The mapping control means according to claim 1 , wherein:
Carriers are grouped into segments by a predetermined number
When there is a
A finite number of seg
The combination pattern of career holes in
A memory circuit for storing
When the occurrence of harmful waves is observed, refer to the memory circuit
The segment pattern corresponding to the interference information
Seg specified to the mapping processing means
The transmission of the carrier wave corresponding to the pattern of the
Together with the pattern information of the specific segment.
Input to the mapping processing means as
Claim 1乃, characterized in that to multiplex transmission with over data
4. The OFDM signal transmitting apparatus according to any one of 3 to 3 . 8. The mapping processing means according to claim 1 , wherein:
The transmission data of the carrier of the specific frequency portion from the signaling control means.
When the data assignment is released, the carrier
Constant data shall be assigned, and the specific frequency portion
Carrier wave is a carrier hole or the specific data
Creates information data to the effect that
Allocated to carrier and multiplexed with other transmission data
OFDM signal transmission device according to any one of claims 1 to 7, characterized in that that. 9. The OFD interference wave information acquiring means,
Abnormality in OFDM transmission band from received signal of M receiver
Detects the recognized frequency components and determines their signal level and frequency.
A series of operations for obtaining the number as the interference information is repeated for each unit time, and the mapping control means performs the interference information.
Review the possibility of allocating the specific data or the specific data that does not allocate the transmission data per unit time according to the signal level and frequency of the report, and change the transmission carrier in accordance with the interference wave generation part, and OFDM according to claim 8, characterized in that so as to change the information of a specific frequency portion of assigning a specific frequency portion or specific data not assign the transmission data Te
Signal sending device.