JPH11215092A - Ofdm signal transmission method and ofdm signal transmitter thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance transmission average power by controlling the amplitude of an orthogonal frequency division multiple(OFDM) time waveform and to improve throughput by reducing transmission errors. SOLUTION: A sending side selects one of scramble systems #1 to #N by a scramble system selecting part 15 and applied it to a sending data system. a scramble method selection controlling part 14 gives selected scramble information to an identifier adding part 16, and the part 16 adds the information to a sending OFDM signal as an identifier. A receiving side detects the identifier and obtains the original data system by selecting a descramble method, based on detection results and descrambling it. It is possible to change an OFDM time waveform by changing a scramble system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an OFD for wirelessly transmitting a digital data sequence using an OFDM signal.
The present invention relates to an M signal transmitting / receiving method and an OFDM signal transmitting / receiving apparatus.

[0002]

2. Description of the Related Art In recent years, attention has been paid to indoor and outdoor high-speed wireless data communication systems. 2. Description of the Related Art In a wireless communication system that realizes high-speed data communication, it is essential to reduce intersymbol interference due to multiple reflection radio wave propagation (multipath propagation) generated by a radio wave propagation environment.

[0003] Deterioration of reception characteristics due to this intersymbol interference is
The larger the data transmission speed and the wider the service area, the larger the data transmission speed. Conventionally, adaptive automatic equalizers such as a maximum likelihood sequence estimator (MLSE) and a decision feedback equalizer (DFE) have been studied as multi-path resistant techniques, but high-speed data communication using high frequencies has been studied. When applied to a system, the scale of the device becomes large. Therefore,
It is impractical to mount an adaptive automatic equalizer on a mobile terminal where miniaturization, low power consumption, and low cost are desired. Moreover,
In small zone communication where the radio wave propagation model cannot be set clearly, an adaptive automatic equalizer cannot be designed.

[0004] Therefore, an OFDM (Orthogonal Frequency Division Multiplexin) that is resistant to a multipath radio wave propagation environment that is inferior in principle and can realize high-quality data transmission.
g) (Orthogonal frequency division multiplexing) transmission system is being studied. The OFDM signal is provided with a guard period (redundancy period) in which a part of the transmission waveform is duplicated, and the guard period absorbs multipath propagation distortion.

However, since the OFDM signal is composed of subcarriers modulated with independent data sequences in a wide band, the amplitude characteristic of the OFDM signal time waveform becomes more Gaussian (normal distribution) as the number of subcarriers increases. Become. Therefore, unlike the single carrier transmission method, the amplitude fluctuation and the maximum amplitude value are large, and a wide dynamic range is required for the transmission / reception device. Therefore, when the back-off of the transmission power amplifier is set small, non-linear distortion due to power amplification occurs. When an OFDM signal is subjected to nonlinear distortion, orthogonality between subcarriers is broken, and transmission characteristics are rapidly deteriorated. For this reason, in particular, the back-off of the transmission power amplifier must be set large, and the transmission power amplifier must be reduced in efficiency.

As a solution to this, a method of controlling transmission power for each OFDM symbol (time waveform) has been studied. In this scheme, all OFDM symbols are normalized by the peak amplitude within that symbol, thereby obtaining all OFDM symbols.
Make the peak power constant with the symbol. Since the peak power is constant for all symbols, the back-off amount of the transmission power amplifier can be reduced and kept constant.

However, as a result, in this method, the transmission power differs for each transmission symbol, so that the transmission quality cannot be made constant. Therefore, for an OFDM symbol having a large amplitude fluctuation and a large amplitude, the suppression of the average power is large, and as a result, transmission quality is deteriorated, that is, a transmission error is likely to occur. In particular, in a communication system that performs data retransmission control, there may be a symbol that cannot be received no matter how many retransmissions, unless the propagation environment changes.

Therefore, as another solution, redundant information (bits) is added to predetermined transmission information (bits) to suppress the amplitude fluctuation and the maximum amplitude value of the time waveform of the OFDM symbol, thereby achieving high efficiency operation of the transmission power amplifier. Techniques for reducing nonlinear distortion are being studied.

This is a method of reducing the maximum amplitude value by changing the transmission waveform of the OFDM signal. However, the transmission / reception device must have a combination table of transmission information and redundant information. This table requires a lot of memory space,
The device scale becomes large. Furthermore, when the receiver receives a combination that does not exist in the table due to a transmission error, there is a possibility that the entire symbol cannot be received.

[0010]

As described above, conventionally, O
In the FDM transmission, a method of normalizing the maximum amplitude of the time waveform for each OFDM symbol and transmitting the signal is sometimes employed in order to operate the transmission power amplifier efficiently without any special large-scale device. Then, send OFDM
Since the transmission quality changes for each symbol, there has been a problem that a propagation error is likely to occur, and it is not suitable for data transmission in which retransmission control can be performed. A method of adding redundant information to transmission information for each OFDM symbol to suppress the maximum amplitude value of the time waveform of the OFDM symbol may be adopted. In this method, a combination of the transmission information and the redundant information is used. There is a problem that the table must be provided in the transmission / reception device, which increases the size of the device, and that when a sequence that does not exist in the table is received, the entire received data sequence must be discarded.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is intended to reduce transmission errors during data transmission by suppressing amplitude fluctuations of an OFDM time waveform and improving transmission average power. It is an object of the present invention to provide an OFDM signal transmission / reception method and an OFDM signal transmission / reception device that can perform the above-described operations.

[0012]

According to a first aspect of the present invention, there is provided an OFDM signal transmitting / receiving method for converting a transmission data sequence into a time waveform of a different OFDM symbol on a transmitting side among wireless stations transmitting / receiving an OFDM signal. And a process of generating a transmission OFDM signal by selecting a conversion process to be used for transmission from a plurality of conversion processes for performing the process, and a process of adding information indicating the conversion process to be used for the transmission as an identifier to the transmission OFDM signal. On the receiving side among the wireless stations that transmit and receive OFDM signals, the transmitting OFDM signal is received, the process of detecting the identifier is performed, and based on the detected identifier, a plurality of inverse transform processes are used for transmission. A reverse conversion process corresponding to the conversion process is selected and the transmission O
And a process for converting an FDM signal into the transmission data sequence.
The signal transmission / reception device transmits a different transmission data sequence to the transmission side among radio stations transmitting / receiving OFDM signals.
Select a conversion process to be used for transmission from a plurality of conversion processes for converting to a time waveform of an FDM symbol, and transmit OFDM
An OFDM signal generating means for generating a signal, and the transmission OFD using information indicating a conversion process used for the transmission as an identifier.
M means for adding to the M signal, between the wireless stations transmitting and receiving OFDM signal, on the receiving side, receiving the transmission OFDM signal, detecting means for detecting the identifier, based on the detected identifier Means for selecting an inverse conversion process corresponding to the conversion process used for transmission from a plurality of inverse conversion processes and converting the transmission OFDM signal into the transmission data sequence.

[0013] In claim 1 of the present invention, on the transmitting side,
To convert a transmission data sequence into a time waveform of a different OFDM symbol, a conversion process used for transmission is selected from a plurality of conversion processes. Thereby, the time waveform of the OFDM symbol to be transmitted can be changed, and the maximum amplitude of the OFDM symbol can be reduced. The selected conversion process is added to the transmission OFDM signal as an identifier and transmitted. On the receiving side, an inverse conversion process corresponding to the conversion process on the transmitting side is selected based on the identifier. The original transmission data sequence is obtained from the received OFDM signal by this inverse conversion process.

According to a tenth aspect of the present invention, OFDM
The transmission data sequence is converted into a time waveform of the OFDM symbol based on the conversion process by the signal generation means. The information indicating the conversion process used for transmission is the transmission OFD as an identifier.
It is added to the M signal and transmitted. On the receiving side, the identifier is detected by the detecting means, and the received OFDM signal is returned to the original transmission data sequence by an inverse conversion process based on the detected identifier.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an OFDM signal transmitting / receiving apparatus according to the present invention. The embodiment shown in FIG. 1 is an example in which the present invention is applied to a base station or a wireless terminal constituting a wireless communication system.

In the present embodiment, the base station lowers the maximum amplitude value of the time waveform of the OFDM symbol to be transmitted by multiplying the transmission data sequence by a predetermined scrambling sequence.

In FIG. 1, a digital transmission data sequence divided in units of scrambling is input to a scrambling unit 10 of the transmission system 1. The transmitting side has a plurality of scramble sequence generation units 11 # 1 to 11 # N. The scramble sequence generation units 11 # 1 to 11 # N
The scramble sequences # 1 to #N are generated and output to the scramble sequence selection unit 15, respectively.

The scramble sequence selection unit 15 is controlled by a scramble method selection control unit 14 described later, selects one of the input scramble sequences # 1 to #N, and outputs it to the scramble unit 10. The scrambler 10 multiplies the transmission data sequence by the input scramble sequence and outputs the result.

The transmission data sequence from scrambler 10 is provided to identifier adder 16. Identifier adding unit 16
Is provided with information indicating the scrambling sequence used for scrambling from the scrambling method selection control unit 14, and this information is added to the transmission data sequence as an identifier and output to the modulation unit 17.

The modulation section 17 performs subcarrier modulation on the input transmission data sequence by a predetermined modulation method. The output of the modulator 17 is supplied to a transmission OFDM signal generator 18. The transmission OFDM signal generation unit 18 performs a fast inverse Fourier transform (IF
FT) to generate a OFDM symbol by performing signal processing such as a conversion process into a time signal by a FT) and a guard period addition process for absorbing a delay wave component by a multipath.
9 is output.

The transmitting unit 19 performs a DA conversion process, a frequency conversion process, a filtering process, an amplification process, and the like on the input OFDM symbol, creates a transmission signal, and supplies the transmission signal to the antenna 20. Antenna 20 emits an OFDM transmission signal.

The scramble method selection control unit 14 controls the scramble sequence selection unit 15 to select a scramble sequence according to a predetermined selection method. For example, the scrambling method selection control unit 14 may cause the scramble sequence # 1 to be selected sequentially or may be selected randomly. Further, when a retransmission request is issued from the receiving side, the scrambling method selection control unit 14
At least for the same data, a scramble sequence different from the previous data is selected.

The scramble method selection control unit 14
May detect the maximum amplitude of the OFDM symbol from the transmission OFDM signal generation unit 18 and select a scrambling sequence such that the maximum amplitude is minimized. Further, the scramble method selection control unit 14 transmits the transmission data sequence and the OFDM
A scramble sequence may be selected so that the maximum amplitude value is minimized by providing a table indicating the correspondence between the symbol and the maximum amplitude value.

On the other hand, in the receiving system, a received signal received via the antenna 21 is supplied to the receiving section 22.
The receiving unit 22 performs a filtering process, an amplification process, a frequency conversion process, an A / D conversion process, etc.
Obtain an FDM symbol. This OFDM symbol is
The signal is supplied to the FDM signal demodulation unit 23.

The received OFDM signal demodulation section 23 performs demodulation processing such as guard period removal processing, Fourier transform processing, and demapping processing on the input OFDM symbol to demodulate the original digital data sequence. Receive OFDM
The demodulated digital data sequence from the signal demodulation unit 23 is supplied to a descramble unit 25 and an identifier detection unit 24.

The identifier detecting section 24 detects an identifier from the demodulated digital sequence and outputs it to the descrambling method selection control section 26. Receiving system 2 also has descramble sequence generating sections 28 # 1 to 28 # N that generate descrambling sequences # 1 to #N corresponding to scramble sequences # 1 to #N used in transmitting system 1, respectively. I have. The descrambling sequence generation units 28 # 1 to 28 # N output the generated descrambling sequences # 1 to #N to the descrambling sequence selection unit 27.

The descrambling method selection control section 26 selects a descrambling sequence corresponding to the scrambling sequence used in the transmission system 1 based on the detection result of the identifier detecting section 24 so as to select the descrambling sequence selection section 2.
7 is controlled. The descrambling sequence selection unit 27 is controlled by the descrambling method selection control unit 26 to select one of the descrambling sequences # 1 to #N and output it to the descrambling unit 25.

The descrambling unit 25 descrambles the received data sequence using the given descrambling sequence. The received data sequence descrambled by the descrambler 25 is output.

Next, the operation of the embodiment configured as described above will be described with reference to FIGS. 2 and 3 are flowcharts illustrating an OFDM signal transmission / reception method according to one embodiment of the present invention.

An OFDM data symbol is transmitted from a transmission system 1 as a base station, and a reception system 2 as a wireless terminal is
An example of receiving a data symbol will be described.

At the base station, the transmission data sequence is scrambled. That is, in step S1 of FIG.
The scramble method selection control unit 14 instructs the scramble sequence selection unit 15 on the scramble sequence to be selected.
According to this instruction, scramble sequence selecting section 15 selects one of scramble sequences # 1 to #N output from scramble sequences 11 # 1 to 11 # N. The selected scramble sequence is provided to the scramble unit 10,
The scrambler 10 scrambles the transmission data sequence in step S2.

In the present embodiment, scramble method selection control section 14 supplies information indicating the scramble sequence used for scrambling to identifier adding section 16. The identifier indicating the scramble sequence is added to the transmission data sequence by the identifier adding unit 16 (step S3).
). Modulating section 17 performs predetermined modulation processing on the output of identifier adding section 16 and outputs the result to transmission OFDM signal generating section 18.

Next, in step S4, the transmission OFDM
The signal generation unit 18 generates an OFDM symbol by performing signal processing such as conversion processing into a time signal by fast inverse Fourier transform (IFFT) and guard period addition processing for absorbing a delayed wave component due to multipath. The OFDM signal is provided to the transmission unit 19, and after being subjected to DA conversion processing, frequency conversion processing, filtering processing, amplification processing, and the like, is transmitted from the antenna 110 as a transmission signal (step S5).

The time waveform of the OFDM symbol output from the transmission OFDM signal generator 18 varies with the scramble sequence even for the same transmission data sequence, and the maximum amplitude also changes. In the transmission system 1, a scramble sequence to be used for transmission is selected and scrambled from a plurality of scramble sequences # 1 to #N.
It is possible to make the maximum amplitude of the time waveform of M symbols relatively small.

Thus, amplification in the transmitting section 19 can be performed with high efficiency without distortion, and transmission errors can be reduced.

On the other hand, the wireless terminal which is the receiving system 2 receives the OFDM signal transmitted by the receiving unit 22 (FIG. 3).
Step S6). In step S7, the received OFDM signal demodulation unit 23 converts the received OFDM symbol
An original digital data sequence is obtained by performing demodulation processing such as guard period removal processing, Fourier transform processing, and demapping processing.

In the present embodiment, the identifier is detected by the identifier detecting section 24 from the demodulated digital data sequence (step S8). This identifier is given to the descrambling method selection control unit 26, and the descrambling method selection control unit 26 instructs the descrambling sequence selection unit 27 to select a descrambling sequence corresponding to the scrambling sequence used in the transmission system 1. Give instructions.

Thus, the descrambling sequence selecting unit 2
7 is a descrambling sequence generator 28 # 1 to 28 # N
Are selected from the descrambling sequences # 1 to #N corresponding to the scrambling sequence used in the transmission system 1 (step S9) and output to the descrambling unit 25.

The digital data sequence from the received OFDM signal demodulation unit 23 is provided to the descramble unit 25, and is returned to the original digital data sequence in the descramble unit 25 (step S10).

Since the identifier is added to the transmission signal from the transmission system 1, even if the scramble sequence is changed in the transmission system 1, the descrambling is surely performed in the reception system 2 without having a combination table in the transceiver. be able to.

By the way, in the transmission system 1, when the scramble method selection control unit 14 does not select the optimum scramble sequence, a transmission error may occur in the transmission OFDM signal. In this case, in the receiving system,
When a transmission error is detected, a retransmission request may be generated.

When such a retransmission request occurs, the transmission system 1 retransmits the data requested to be retransmitted. In this case, scramble method selection control section 14 instructs scramble sequence selection section 15 to select a scramble sequence other than the scramble sequence used for the data before retransmission. Thereby, O from the transmission OFDM signal generation unit 18
The time waveform of the FDM symbol is likely to have a smaller maximum amplitude than the time waveform of the previously output OFDM symbol. This increases the possibility that the data retransmitted in the receiving system 2 can be received without error.

As described above, in the present embodiment, a scramble sequence to be applied to a digital data sequence to be transmitted can be selected from a plurality of scramble sequences, so that the amplitude fluctuation of the OFDM time waveform is suppressed, and the transmission average power is reduced. Can be improved. As a result, transmission errors can be reduced and throughput can be improved, and power consumption of the transmitting and receiving apparatus can be reduced. Also, since information of the selected scramble sequence is added as an identifier and transmitted, descrambling is possible without having a combination table in the transceiver.

In the present embodiment, the transmitting side is described as having a configuration having a plurality of scrambling sequence generators in parallel, but only the generating polynomial necessary for generating the scrambling sequence is stored in the memory. May be used. Therefore, the identifier indicating the scramble sequence may not be the scramble sequence itself, but may be an identifier such as a number determined by the transmitting side and the receiving side, or may be a hexadecimal or octal number describing a generator polynomial. . The receiving side forming a pair may have the same configuration as the transmitting side.

The transmission data sequence input to scramble section 10 may be scrambled for concealment.

FIG. 4 is a block diagram showing another embodiment of the present invention. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The present embodiment is different from the embodiment of FIG. 1 in that the transmission data sequence is encoded instead of scrambled. The transmission data sequence is divided into units to be encoded and supplied to the encoding unit 30. The transmitting side has a plurality of encoding method storage units 31 # 1 to 31 # N. The encoding method storage units 31 # 1 to 31 # N output the stored encoding methods # 1 to #N to the encoding method selection unit 35.

Various encoding methods can be considered as the encoding methods stored in the encoding method storage units 31 # 1 to 31 # N.
For example, as an encoding method, error detection encoding or error correction encoding for detecting an error code on the receiving side or correcting the detected error code can be considered.

The encoding method selection unit 35 is controlled by the encoding method selection control unit 34 to select one of the input encoding methods # 1 to #N and output it to the encoding unit 30. The encoding unit 30 encodes the transmission data sequence using the encoding method input thereto and outputs the encoded data to the identifier adding unit 16.

The encoding method selection control section 34 controls the encoding method selection section 35 to select an encoding method according to a predetermined selection method. For example, the encoding method selection control unit 34 may cause the encoding method # 1 to be selected sequentially or may be selected at random. In addition, when a retransmission request is issued from the receiving side, the encoding method selection control unit 34 selects an encoding method different from the previous encoding method for at least the same data.

The encoding method selection control unit 34 may detect the maximum amplitude of the OFDM symbol from the transmission OFDM signal generation unit 18 and select an encoding method so that the maximum amplitude is minimized. Further, the encoding method selection control unit 3
4 may include a table indicating the correspondence between the transmission data sequence and the maximum amplitude value of the OFDM symbol, and select an encoding method such that the maximum amplitude value is minimized.

On the receiving side, the demodulated digital data sequence from the received OFDM signal demodulator 23 is supplied to the decoder 39 and the identifier detector 24. The identifier detection unit 24 detects an identifier from the demodulated digital sequence and outputs the identifier to the decoding method selection control unit 36.

The receiving side also has decoding method storage sections 38 # 1 to 38 # N that output decoding methods # 1 to #N corresponding to encoding methods # 1 to #N used on the transmitting side, respectively. doing. The decoding method storage units 38 # 1 to 38 # N output the stored decoding methods # 1 to #N to the decoding method selection unit 37.

The decoding method selection control unit 36 selects a decoding method corresponding to the encoding method used on the transmission side based on the detection result of the identifier detection unit 24.
It controls the decoding method selection unit 37. Decoding method selection unit 3
7 is controlled by the decoding method selection control unit 36 to select one of the decoding methods # 1 to #N and output it to the decoding unit 39.

Decoding section 39 decodes the received data sequence using a given decoding method. The received data sequence decoded by the decoding unit 39 is output.

The other structure is the same as that of the embodiment shown in FIG.

Next, the operation of the embodiment configured as described above will be described.

The digital transmission data sequence is input to the encoding unit 30 after being divided into units for encoding. The encoding method selection unit 35 is controlled by the encoding method selection control unit 34 to select one of the plurality of encoding methods # 1 to #N and output it to the encoding unit 30. The encoding unit 30 encodes the digital transmission data sequence by a designated encoding method and outputs the encoded data to the identifier adding unit 16. Information indicating the encoding method used for encoding is given from the encoding method selection control unit 34 to the identifier adding unit 16.
6 adds this information as an identifier to the transmission data and outputs it.

Other processes on the transmitting side are the same as those in the embodiment of FIG. The time waveform of the OFDM symbol output from the transmission OFDM signal generation unit 18 changes depending on the encoding method even for the same transmission data sequence, and the maximum amplitude also changes. On the transmitting side, the encoding method used for transmission is selected from a plurality of encoding methods # 1 to #N to perform encoding, so that the maximum amplitude of the time waveform of the OFDM symbol can be made relatively small. It is.

On the receiving side, the digital data sequence demodulated by the received OFDM signal demodulation unit 23 is provided to the identifier detection unit 24 and the decoding unit 39.
The selection of the decoding method based on the identifier detected by the identifier detector 24 is the same as in the embodiment of FIG.
Decoding section 39 decodes and outputs the received digital data sequence using the selected decoding method.

Other operations are the same as those of the embodiment shown in FIG.

As described above, in the present embodiment, it is possible to select an encoding method to be applied to a digital data sequence to be transmitted from a plurality of encoding methods, so that the amplitude fluctuation of the OFDM time waveform is suppressed, and the transmission average power is reduced. Can be improved. As a result, transmission errors can be reduced and throughput can be improved, and power consumption of the transmitting and receiving apparatus can be reduced. In addition, since information on the selected encoding method is added as an identifier and transmitted, decoding can be performed without a combination table in the transceiver.

Although the transmitting side is described in a configuration having a plurality of encoding method storage sections in parallel, a configuration in which only generator polynomials necessary for encoding are stored in a memory may be used. A hexadecimal or octal number that describes the generator polynomial may be used. Therefore, the identifier indicating the encoding method is not limited to the encoding method itself, and may be an identifier such as a number indicating a combination of the encoding method and the decoding method decided between the transmitting side and the receiving side. The receiving side forming a pair may have the same configuration as the transmitting side.

FIG. 5 is a block diagram showing another embodiment of the present invention. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment is different from the embodiment of FIG. 1 in that bit interleaving is performed instead of scrambling the transmission data sequence. The transmission data sequence is divided into units for performing bit interleaving and supplied to the bit interleaving section 40. The transmitting side has a plurality of bit interleaving procedure storage units 41 # 1 to 41 # N. Bit interleave procedure storage units 41 # 1 to 41 # 41
#N is the stored bit interleave procedure #
1 to #N are output to the bit interleave procedure selecting unit 45.

The bit interleave procedure selection section 45 is controlled by the bit interleave procedure selection control section 44,
One of the input bit interleaving procedures # 1 to #N
One is selected and output to the bit interleaving section 40.
The bit interleaving section 40 bit-interleaves the transmission data sequence according to the input bit interleaving procedure and outputs the transmission data sequence to the identifier adding section 16.

Bit interleave procedure selection control unit 44
Controls the bit interleave procedure selector 45,
The bit interleaving procedure is selected by a predetermined selection method. For example, the bit interleave procedure selection control unit 44 may cause the bit interleave procedure # 1 to be selected in order or may be selected randomly. Further, when a retransmission request is issued from the receiving side, the bit interleave procedure selection control unit 44 causes a bit interleave procedure different from the previous one to be selected for at least the same data.

The bit interleave procedure selection control unit 44 controls the OFDM signal from the transmission OFDM signal generation unit 18
The maximum amplitude of the symbol may be detected, and the bit interleaving procedure may be selected such that the maximum amplitude is minimized.
Furthermore, the bit interleaving procedure selection control unit 44 may include a table indicating the correspondence between the transmission data sequence and the maximum amplitude value of the OFDM symbol, and select the bit interleaving procedure so that the maximum amplitude value is minimized.

On the other hand, on the receiving side, the demodulated digital data sequence from the received OFDM signal demodulator 23 is supplied to the bit deinterleaver 49 and the identifier detector 24. The identifier detection unit 24 detects an identifier from the demodulated digital sequence and outputs the identifier to the bit deinterleaving procedure selection control unit 46.

On the receiving side, bit deinterleaving procedure storage sections 48 # 1 to 48 # N for outputting bit deinterleaving procedures # 1 to #N corresponding to bit interleaving procedures # 1 to #N used on the transmitting side, respectively. have. The bit deinterleave procedure storage units 48 # 1 to 48 # N output the stored bit deinterleave procedures # 1 to #N to the bit deinterleave procedure selection unit 47.

Bit deinterleaving procedure selection control unit 4
6 controls the bit deinterleaving procedure selecting section 47 so as to select a bit deinterleaving procedure corresponding to the bit interleaving procedure used on the transmitting side based on the detection result of the identifier detecting section 24. The bit deinterleave procedure selection unit 47 is controlled by the bit deinterleave procedure selection control unit 46 to select one of the bit deinterleave procedures # 1 to #N and output it to the bit deinterleave unit 49.

Bit deinterleaving section 49 obtains a digital data sequence in the original order by bit deinterleaving the received data sequence according to a given bit deinterleaving procedure. The bit deinterleaving section 49 outputs the bit deinterleaved received data sequence.

The other structure is the same as that of the embodiment shown in FIG.

Next, the operation of the embodiment configured as described above will be described.

The digital transmission data sequence is divided into units for performing bit interleaving and input to bit interleaving section 40. The bit interleave procedure selection unit 45 is controlled by the bit interleave procedure selection control unit 44, selects one of the plurality of bit interleave procedures # 1 to #N, and
Output to 0. The bit interleaving section 40 bit-interleaves the digital transmission data sequence according to a designated bit interleaving procedure, and
6 is output. Information indicating the bit interleaving procedure used for the bit interleaving is given to the identifier adding section 16 from the bit interleaving procedure selection control section 44. The identifier adding section 16 adds this information as an identifier to the transmission data and outputs it. I do.

Other processes on the transmitting side are the same as those in the embodiment of FIG. The time waveform of the OFDM symbol output from the transmission OFDM signal generation unit 18 changes by the bit interleaving procedure even for the same transmission data sequence, and the maximum amplitude also changes. On the transmitting side, bit interleaving is performed by selecting a bit interleaving procedure to be used for transmission from a plurality of bit interleaving procedures # 1 to #N, so that the maximum amplitude of the time waveform of an OFDM symbol can be made relatively small. It is.

On the receiving side, on the other hand, the digital data sequence demodulated by the received OFDM signal demodulator 23 is transmitted to the identifier detector 24 and the bit deinterleaver 4.
9 given. The bit deinterleaving procedure based on the identifier detected by the identifier detector 24 is selected as in the embodiment of FIG. Bit deinterleaving section 49 bit deinterleaves the received digital data sequence using the selected bit deinterleaving procedure, and outputs it.

Other functions are the same as those of the embodiment shown in FIG.

As described above, in the present embodiment, a bit interleaving procedure applied to a digital data sequence to be transmitted can be selected from a plurality of bit interleaving procedures, so that amplitude fluctuations of the OFDM time waveform are suppressed, and transmission average power is reduced. Can be improved. As a result, transmission errors can be reduced and throughput can be improved, and power consumption of the transmitting and receiving apparatus can be reduced. In addition, since information on the selected bit interleaving procedure is added as an identifier and transmitted, bit deinterleaving is possible without having a combination table in the transceiver.

Although the transmitting side is described as having a plurality of bit interleaving procedure storage units in parallel,
A configuration in which a rearrangement table necessary for bit interleaving is simply stored in a memory may be used. The identifier indicating the bit interleave procedure need not indicate the reordering table itself, but may be a number or the like indicating a combination of the bit interleave procedure and the bit deinterleave procedure decided between the transmitting side and the receiving side. The receiving side forming a pair may have the same configuration as the transmitting side.

FIG. 6 is a block diagram showing another embodiment of the present invention. 6, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment differs from the embodiment of FIG. 1 in that subcarrier interleaving is performed instead of scrambling the transmission data sequence. In the present embodiment, subcarrier interleaving section 50 is provided between modulating section 17 and transmission OFDM signal generating section 18.

In the present embodiment, the transmission data sequence is divided into units for generating an OFDM symbol and supplied to the identifier adding unit 16. The identifier adding section 16 is provided with information on a subcarrier interleaving procedure selected on the transmitting side from a subcarrier interleaving procedure selection control section 54 described later, and adds this information as an identifier to a transmission data sequence to modulate the transmission section. Output.

The transmitting side has a plurality of subcarrier interleaving procedure storage units 51 # 1 to 51 # N. Subcarrier interleave procedure storage units 51 # 1 to 51 #
N outputs the stored subcarrier interleaving procedures # 1 to #N to the subcarrier interleaving procedure selecting unit 55.

Subcarrier interleaving procedure selector 5
5 is a subcarrier interleave procedure selection control unit 54
, And selects one of the inputted subcarrier interleaving procedures # 1 to #N and outputs it to the subcarrier interleaving section 50. The subcarrier interleaving section 50 performs subcarrier interleaving on the transmission data sequence according to the input subcarrier interleaving procedure, and outputs the transmission OFDM signal to the transmission OFDM signal generation section 18.

The subcarrier interleaving section 50
Are designed not to perform subcarrier interleaving on subcarriers corresponding to identifiers.

The sub-carrier interleave procedure selection control unit 54 includes a sub-carrier interleave procedure selection unit 55
Is controlled to select a subcarrier interleaving procedure by a predetermined selection method, and information on the selected subcarrier interleaving procedure is supplied to the identifier adding unit 16. There are various selection methods by the subcarrier interleaving procedure selection control unit 54. For example, the selection method may be selected in order from the subcarrier interleaving procedure # 1, or may be selected at random. Further, when a retransmission request is issued from the receiving side, the subcarrier interleave procedure selection control unit 54 causes a subcarrier interleave procedure different from the previous one to be selected for at least the same data.

Further, subcarrier interleave procedure selection control section 54 outputs ODM signal from transmission OFDM signal generation section 18.
The maximum amplitude of the FDM symbol may be detected, and the subcarrier interleaving procedure may be selected such that the maximum amplitude is minimized. Furthermore, the subcarrier interleave procedure selection control unit 54 includes a table indicating the correspondence between the transmission data sequence and the maximum amplitude value of the OFDM symbol, and may select the subcarrier interleave procedure so that the maximum amplitude value is minimized. Good.

On the receiving side, the OFDM symbol from receiving section 22 is supplied to received OFDM signal receiving section 61. The received OFDM signal receiving unit 61 performs a guard period removal process and a Fourier transform process on the input OFDM symbol to return to the subcarrier state, and sends the received signal to the identifier subcarrier detection unit 62 and the subcarrier deinterleave unit 59. Output.

The identifier subcarrier detecting section 62 detects the subcarrier of the identifier from the reproduced subcarriers and outputs it to the identifier subcarrier demodulating section 63. The identifier subcarrier demodulator 63 demodulates the subcarrier of the identifier to obtain the identifier. At the time of transmission, subcarriers corresponding to identifiers are not subject to subcarrier interleaving, so that only the identifiers can be demodulated by the identifier subcarrier demodulator 63. This identifier is supplied to the subcarrier deinterleave procedure selection control unit 56.

On the receiving side, subcarrier deinterleaving procedure storage section 58 # 1 for outputting subcarrier deinterleaving procedures # 1 to #N corresponding to subcarrier interleaving procedures # 1 to #N used on the transmitting side, respectively.
To 58 # N. The subcarrier deinterleave procedure storage units 58 # 1 to 58 # N output the stored subcarrier deinterleave procedure # 1 to #N to the subcarrier deinterleave procedure selection unit 57.

The subcarrier deinterleave procedure selection control section 56 controls the subcarrier deinterleave procedure so as to select a subcarrier deinterleave procedure corresponding to the subcarrier interleave procedure used on the transmitting side based on the detection result of the identifier. It controls the procedure selecting section 57. Subcarrier deinterleaving procedure selecting section 57
Is a subcarrier deinterleaving procedure selection control unit 56
And subcarrier deinterleaving procedure # 1
To #N and outputs it to the subcarrier deinterleaving section 59.

The subcarrier deinterleave section 59
Subcarriers of received data are subcarrier deinterleaved according to a given subcarrier deinterleaving procedure to obtain subcarriers in the original order.
The output of the subcarrier deinterleaving section 59 is
4 given. The demodulation unit 64 is configured to return the input subcarriers to a received data sequence and output them by performing processes such as demapping and bit determination.

It is apparent that various control methods can be employed for the control method of subcarrier interleave procedure selection control section 54, similarly to the above embodiments.

The other structure is the same as that of the embodiment shown in FIG.

Next, the operation of the embodiment configured as described above will be described.

The digital transmission data sequence is divided into units for generating OFDM symbols and input to identifier adding section 16. The identifier adding section 16 is provided with information indicating the subcarrier interleaving procedure used for the subcarrier interleaving from the subcarrier interleaving procedure selection control section 54, and the identifier adding section 16 uses this information as an identifier in the transmission data sequence. Add and output.

The transmission data sequence from identifier adding section 16 is applied to modulating section 17 and subcarrier modulated. In the present embodiment, the modulation output is supplied to subcarrier interleaving section 50.

On the other hand, the subcarrier interleave procedure selecting section 55 is controlled by the subcarrier interleave procedure selection control section 54 to select one of the plurality of subcarrier interleave procedures # 1 to #N to perform subcarrier interleave. Output to the unit 50. Subcarrier interleaving section 50 performs subcarrier interleaving on the input digital transmission data sequence according to a specified subcarrier interleaving procedure, and outputs the result to transmission OFDM signal generation section 18. In this case, the subcarriers of the identifier are not interleaved.

Other processes on the transmitting side are the same as those in the embodiment of FIG. The time waveform of an OFDM symbol output from transmission OFDM signal generation section 18 changes by the subcarrier interleaving procedure even for the same transmission data sequence, and the maximum amplitude also changes. On the transmitting side, a plurality of subcarrier interleaving procedures # 1 through #
Since subcarrier interleaving is performed by selecting a subcarrier interleaving procedure used for transmission from N, it is possible to make the maximum amplitude of the time waveform of an OFDM symbol relatively small.

On the receiving side, the OFDM symbol received by receiving section 22 is provided to received OFDM signal receiving section 61. The reception data is returned to the subcarrier by the reception OFDM signal reception unit 61 and supplied to the subcarrier deinterleave unit 59 and the identifier subcarrier detection unit 62.

The identifier subcarrier detecting section 62 detects the subcarrier of the identifier and outputs the identifier subcarrier demodulating section 6
3, and the identifier subcarrier demodulation unit 63 obtains an identifier by demodulation. This identifier is supplied to the subcarrier deinterleave procedure selection control unit 56. The subcarrier deinterleave procedure selection control unit 56 causes the subcarrier deinterleave procedure corresponding to the subcarrier interleave procedure on the transmission side to be selected based on the identifier.

[0103] Subcarrier deinterleaving procedure selecting section 57 gives the selected subcarrier deinterleaving procedure to subcarrier deinterleaving section 59. As a result, the received subcarriers are deinterleaved and supplied to the demodulation section 64. The demodulation unit 64 performs processing such as demapping processing and bit determination on the subcarriers returned in the original order to obtain the original forward data sequence.

The other operations are the same as those of the embodiment shown in FIG.

As described above, in the present embodiment, a subcarrier interleaving procedure to be applied to a digital data sequence to be transmitted can be selected from a plurality of subcarrier interleaving procedures. Average power can be improved. As a result, transmission errors can be reduced and throughput can be improved, and power consumption of the transmitting and receiving apparatus can be reduced. Also, since information on the selected subcarrier interleaving procedure is added and transmitted as an identifier, subcarrier deinterleaving is possible at the transceiver without providing a combination table.

Although the transmitting side is described as having a plurality of subcarrier interleaving procedure storage sections in parallel, a configuration in which a rearrangement table necessary for subcarrier interleaving is merely stored in a memory may be used. . The identifier indicating the subcarrier interleaving procedure does not need to indicate the rearrangement table itself, but may be a number or the like that represents a combination of the subcarrier interleaving procedure and the subcarrier deinterleaving procedure decided on the transmitting side and the receiving side. The receiving side forming a pair may have the same configuration as the transmitting side.

The above embodiments are examples in which an identifier is added to a transmission data sequence as an identifier bit.
In this case, an additional method shown in the explanatory diagram of FIG. 7 can be considered.

FIG. 7A shows an example in which one OFDM symbol is composed of a head identifier bit 70 followed by a transmission data bit sequence 71. FIG. 7B shows one OFD
This is an example in which M symbols are composed of a transmission data bit sequence (1) 73 at the head, a central identifier bit 72, and a transmission data bit sequence (2) 74 that follows. FIG. 7 (c)
Is an example in which one OFDM symbol is composed of a transmission data bit sequence 76 at the head and an identifier bit 75 following the transmission data bit sequence 76.

FIG. 8 is a block diagram showing another embodiment of the present invention. 8, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. This embodiment shows an example in which an identifier is added not as an identifier bit but as an identifier subcarrier. This embodiment employs a method of multiplying a transmission data sequence by a scramble sequence in order to lower the maximum amplitude value of the time waveform of an OFDM symbol to be transmitted.

[0110] Modulation section 17 performs OFDM subcarrier modulation on the output of scramble section 10 using a predetermined modulation scheme, and generates an OFDM subcarrier sequence based on a transmission data sequence. In the present embodiment, OFD from modulation section 17
The M subcarrier sequence is provided by an identifier subcarrier adding unit 81
Is supplied to the transmission OFDM signal generation unit 18 via the.

The information on the scramble sequence selected on the transmission side is supplied from the scramble method selection control unit 14 to the identifier subcarrier addition unit 81. The identifier subcarrier adding unit 81 adds this information as an identifier.
In the present embodiment, identifier subcarrier adding section 8
No. 1 adds an identifier to the OFDM subcarrier sequence from the modulator 17 as an identifier subcarrier.

The OFDM subcarrier sequence to which the identifier carrier has been added by the identifier subcarrier adding section 81 is supplied to the transmission OFDM signal generating section 18.

On the receiving side, the OFDM symbol from receiving section 22 is supplied to received OFDM signal receiving section. The received OFDM signal receiving unit 82 performs a guard period removal process and a Fourier transform process on the input OFDM symbol, returns to a subcarrier sequence, and outputs the subcarrier sequence to the identifier subcarrier detection unit 84 and the demodulation unit 83. The demodulation unit 83 performs processing such as demapping processing and bit determination on the subcarrier sequence, returns the digital data sequence to the descrambling unit 25, and outputs the digital data sequence.

[0114] The identifier subcarrier detection section 84 detects the subcarrier of the identifier from the reproduced subcarrier sequence and outputs it to the identifier subcarrier demodulation section 85. The identifier subcarrier demodulation unit 85 obtains an identifier by demodulating the subcarrier of the identifier. This identifier is supplied to the descrambling method selection control unit 26.

As a result, in this embodiment as well, FIG.
As in the case of the first embodiment, a descrambling sequence corresponding to the scrambling sequence used on the transmission side is selected and supplied to the descrambling unit 25.

The other structure is the same as that of the embodiment shown in FIG.

Next, the operation of the embodiment configured as described above will be described.

In the base station, the transmission data sequence is scrambled. That is, the scramble method selection control unit 1
4 instructs the scramble sequence selector 15 to select a scramble sequence to be selected. Scramble sequence selector 15
According to the instruction, scramble sequences 11 # 1 to 11 # 1
1 selects one of scramble sequences # 1 to #N output from #N. The selected scramble sequence is provided to scramble unit 10, and scramble unit 10 scrambles the transmission data sequence. The output of the scrambler 10 is converted into an OFDM subcarrier sequence by the modulator 17 and supplied to the identifier subcarrier adder 81.

In the present embodiment, scramble method selection control section 14 transmits information indicating the scramble sequence used for scrambling to identifier subcarrier addition section 81.
To supply. The identifier indicating the scramble sequence is added as an identifier subcarrier by the identifier subcarrier adding unit 81.

OFDM with identifier subcarrier added
The subcarriers are provided to the transmission OFDM signal generation unit 18 to perform signal processing such as conversion processing into time signals by fast inverse Fourier transform (IFFT) and guard period addition processing for absorbing delayed wave components due to multipath. Done o
An FDM symbol is generated.

Other processes on the transmitting side are the same as those in the embodiment of FIG. As described above, the transmitting side transmits the identifier to the receiving side using the identifier subcarrier.

On the other hand, the receiving-side wireless terminal receives the OFDM symbol from receiving section 22 and supplies it to received OFDM signal receiving section. The received data is returned to the subcarrier sequence by the received OFDM signal receiving unit 82 and supplied to the demodulation unit 83 and the identifier subcarrier detection unit 84. The demodulation unit 83 converts the subcarrier sequence back to the original digital data sequence and outputs it to the descrambling unit 25.

The identifier subcarrier detecting section 84 detects the subcarrier of the identifier and outputs the identifier subcarrier demodulating section 8
5, and the identifier subcarrier demodulation unit 85 obtains an identifier by demodulation. This identifier is supplied to the descrambling method selection control unit 26. The descrambling method selection control unit 26 selects a descrambling method corresponding to the scrambling method on the transmitting side based on the identifier.

The descrambling sequence selecting section 27 gives the selected descrambling method to the descrambling section 25. As a result, the received digital data sequence is descrambled to obtain the original received data sequence.

Other functions are the same as those of the embodiment shown in FIG.

As described above, in the present embodiment, an identifier is directly inserted into a transmission OFDM subcarrier sequence, and the same effect as in the embodiment of FIG. 1 can be obtained.

Further, in the present embodiment, the transmitting side is described with a configuration having a plurality of scrambling sequence generating sections in parallel, but only the generating polynomial necessary for generating the scrambling sequence is stored in the memory. May be used. Therefore, the identifier indicating the scramble sequence may not be the scramble sequence itself, but may be an identifier such as a number determined by the transmitting side and the receiving side, or may be a hexadecimal or octal number describing a generator polynomial. . The receiving side forming a pair may have the same configuration as the transmitting side.

FIG. 9 is a block diagram showing another embodiment of the present invention. In FIG. 9, the same components as those in FIGS. 4 and 8 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment selects an encoding method for changing the time waveform of an OFDM symbol, and
This is an example in which an identifier is transmitted by a subcarrier.

This embodiment is different from the embodiment shown in FIG. 8 in that transmission data sequences are not scrambled but are encoded. The transmission data sequence is divided into units to be encoded and supplied to the encoding unit 30. The transmission side selects one of a plurality of encoding methods # 1 to #N and uses it in the encoding unit 30 as in the embodiment of FIG.

The encoding method selection control section 34 outputs information on the selected encoding method to the identifier subcarrier adding section 81. The fact that the identifier subcarrier adding section 81 transmits the identifier by the identifier subcarrier is the same as in the embodiment of FIG.

On the other hand, on the receiving side, the digital data sequence from demodulation section 83 is applied to decoding section 39.
On the receiving side, the decoding method selection control unit 36 selects the decoding methods # 1 to #N corresponding to the encoding methods # 1 to #N used on the transmission side.
Numeral 9 restores the original digital data sequence by decoding according to the designated decoding method and outputs it.

The other structure is the same as that of the embodiment shown in FIGS.

Next, the operation of the embodiment configured as described above will be described.

[0135] The digital transmission data sequence is divided into coding units and input to the coding unit 30. The encoding method selection unit 35 is controlled by the encoding method selection control unit 34 to select one of the plurality of encoding methods # 1 to #N and output it to the encoding unit 30. Encoding section 30 encodes the digital transmission data sequence by a specified encoding method and outputs the result to modulation section 17. A subcarrier sequence is obtained by the modulator 17 and the identifier subcarrier adding unit 81
Is supplied to the transmission OFDM signal generation unit 18 via

Information indicating the encoding method used for encoding is given from the encoding method selection control section 34 to the identifier subcarrier adding section 81. A carrier is added to a subcarrier sequence based on transmission data and output.

The other processes on the transmitting side are the same as those in the embodiment shown in FIGS. Transmission OFDM signal generator 18
The time waveform of the OFDM symbol output from is changed by the encoding method even if the transmission data sequence is the same,
Its maximum amplitude also changes. On the transmitting side, the encoding method used for transmission is selected from a plurality of encoding methods # 1 to #N to perform encoding, so that the maximum amplitude of the time waveform of the OFDM symbol can be made relatively small. It is.

On the receiving side, the OFDM symbol from receiving section 22 is provided to received OFDM signal receiving section 82, and a subcarrier sequence is obtained. The subcarrier sequence is demodulated into a digital data sequence by the demodulation unit 83 and provided to the decoding unit 39.

The output of the medical examination OFDM signal receiving section 82 is also supplied to an identifier subcarrier detecting section 84, and the identifier subcarrier is detected. The identifier demodulated from the identifier subcarrier is provided to the decoding method selection control unit 36, and a decoding method corresponding to encoding on the transmission side is selected.

Decoding section 39 obtains a received digital data sequence by decoding the output of demodulation section 83 by a designated decoding method.

Other operations are the same as those of the embodiment shown in FIGS.

As described above, in this embodiment, it is apparent that the same effects as those in the embodiments of FIGS. 4 and 8 can be obtained.

Although the transmitting side is described with a configuration having a plurality of encoding methods in parallel, a configuration in which only generator polynomials necessary for encoding are stored in a memory may be used. Also, the identifier indicating the encoding method may not be the generator polynomial itself expressing the encoding, but may be an identifier such as a number decided on the transmitting side and the receiving side, or a hexadecimal or octal number describing the generator polynomial. It may be a number. The receiving side forming a pair may have the same configuration as the transmitting side.

FIG. 10 is a block diagram showing another embodiment of the present invention. 10, the same components as those in FIGS. 5 and 8 are denoted by the same reference numerals, and description thereof will be omitted.

The present embodiment is an example in which a bit interleaving procedure is selected to change the time waveform of an OFDM symbol, and an identifier is transmitted by a subcarrier.

This embodiment is different from the embodiment of FIG. 8 in that bit interleaving is performed instead of scrambling the transmission data sequence. The transmission data sequence is divided into units for performing bit interleaving and supplied to the bit interleaving section 40. The transmission side selects one of a plurality of bit interleaving procedures # 1 to #N and uses it in bit interleaving section 40 as in the embodiment of FIG.

The bit interleaving procedure selection control section 44 outputs information on the selected bit interleaving procedure to the identifier subcarrier adding section 81. The fact that the identifier subcarrier adding section 81 transmits the identifier by the identifier subcarrier is the same as in the embodiment of FIG.

On the other hand, on the receiving side, the digital data sequence from demodulation section 83 is converted into bit deinterleave section 4
9 given. On the receiving side, bit deinterleaving procedure selection control unit 46 selects bit deinterleaving procedures # 1 to #N corresponding to bit interleaving procedures # 1 to #N used on the transmitting side,
The bit deinterleave unit 49 restores the original digital data sequence by decoding according to the designated bit deinterleave procedure, and outputs it.

The other structure is the same as that of the embodiment shown in FIGS.

Next, the operation of the embodiment configured as described above will be described.

The digital transmission data sequence is divided into units for performing bit interleaving and input to bit interleaving section 40. The bit interleave procedure selection unit 45 is controlled by the bit interleave procedure selection control unit 44, selects one of the plurality of bit interleave procedures # 1 to #N, and
Output to 0. The bit interleaving section 40 bit-interleaves the digital transmission data sequence by a designated bit interleaving procedure and outputs the result to the modulation section 17. A subcarrier sequence is obtained by modulating section 17,
The signal is supplied to the transmission OFDM signal generation unit 18 via the identifier subcarrier addition unit 81.

Information indicating the bit interleaving procedure used for bit interleaving is given from the bit interleaving procedure selection control section 44 to the identifier subcarrier adding section 81.
Adds this information as an identifier subcarrier to a subcarrier sequence based on transmission data and outputs it.

The other processes on the transmission side are the same as those in the embodiment shown in FIGS. Transmission OFDM signal generator 18
The time waveform of the OFDM symbol output from the CDMA varies with the bit interleaving procedure even for the same transmission data sequence, and its maximum amplitude also varies. On the transmitting side, bit interleaving is performed by selecting a bit interleaving procedure to be used for transmission from a plurality of bit interleaving procedures # 1 to #N, so that the maximum amplitude of the time waveform of an OFDM symbol can be made relatively small. It is.

On the receiving side, the OFDM symbol from receiving section 22 is provided to received OFDM signal receiving section 82, and a subcarrier sequence is obtained. This subcarrier sequence is demodulated into a digital data sequence by demodulation section 83 and applied to bit deinterleave section 49.

The output of the medical examination OFDM signal receiving unit 82 is also supplied to an identifier subcarrier detecting unit 84, and the identifier subcarrier is detected. The identifier demodulated from the identifier subcarrier is provided to the bit deinterleaving procedure selection control unit 46, and the bit deinterleaving procedure corresponding to the bit interleaving on the transmitting side is selected.

Bit deinterleaving section 49 obtains a received digital data sequence by bit deinterleaving the output of demodulation section 83 according to a designated bit deinterleaving procedure.

Other operations are the same as those of the embodiment shown in FIGS.

As described above, in this embodiment, it is apparent that the same effects as those in the embodiments of FIGS. 5 and 8 can be obtained.

Although the transmitting side is described as having a plurality of bit interleaving procedure storage sections in parallel,
A configuration in which a rearrangement table necessary for bit interleaving is simply stored in a memory may be used. The identifier indicating the bit interleave procedure need not indicate the reordering table itself, but may be a number or the like indicating a combination of the bit interleave procedure and the bit deinterleave procedure decided between the transmitting side and the receiving side. The receiving side forming a pair may have the same configuration as the transmitting side.

FIG. 11 is a block diagram showing another embodiment of the present invention. In FIG. 10, the same components as those in FIGS. 6 and 8 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment is an example in which a subcarrier interleaving procedure is selected to change the time waveform of an OFDM symbol, and an identifier is transmitted by a subcarrier.

This embodiment differs from the embodiment of FIG. 8 in that subcarrier interleaving is performed instead of scrambling the transmission data sequence. The transmission data sequence is divided into units for generating OFDM symbols, and
7 is supplied. The transmission subcarrier sequence subcarrier-modulated by modulation section 17 is supplied to subcarrier interleaving section 50. The transmission side selects one of a plurality of subcarrier interleaving procedures # 1 to #N and uses it in subcarrier interleaving section 50 as in the embodiment of FIG.

[0163] Subcarrier interleaving procedure selection control section 54 outputs information on the selected subcarrier interleaving procedure to identifier subcarrier adding section 81.
The fact that the identifier subcarrier adding section 81 transmits the identifier by the identifier subcarrier is the same as in the embodiment of FIG.

On the receiving side, the OFDM symbol from receiving section 22 is provided to received OFDM signal receiving section 82, and a subcarrier sequence is obtained. This subcarrier sequence is provided to subcarrier deinterleave section 59. On the receiving side, subcarrier deinterleaving procedure selection control section 56 selects subcarrier deinterleaving procedures # 1 to #N corresponding to subcarrier interleaving procedures # 1 to #N used on the transmitting side. The carrier deinterleaving section 59 performs subcarrier deinterleaving according to a specified subcarrier deinterleaving procedure, and the demodulation section 82 restores and outputs the original digital data sequence.

The other structure is the same as that of the embodiment shown in FIGS.

Next, the operation of the embodiment configured as described above will be described.

The digital transmission data sequence is divided into units for generating OFDM symbols and input to modulation section 17. Modulating section 17 converts the transmission data sequence into a subcarrier data sequence and outputs the result to subcarrier interleaving section 50. Subcarrier interleaving procedure selecting section 55
Are controlled by the subcarrier interleave procedure selection control unit 54, and a plurality of subcarrier interleave procedures #
One of # 1 to #N is selected and output to subcarrier interleaving section 50.

Subcarrier interleaving section 50 performs subcarrier interleaving on the subcarrier data sequence according to the specified subcarrier interleaving procedure, and outputs the result to identifier subcarrier adding section 81.

[0169] Information indicating the subcarrier interleaving procedure used for the subcarrier interleaving is given to the identifier subcarrier adding section 81 from the subcarrier interleaving procedure selection control section 54. Is added to a subcarrier sequence based on transmission data as an identifier subcarrier, and is output.

The other processes on the transmitting side are the same as those in the embodiment shown in FIGS. Transmission OFDM signal generator 18
The time waveform of the OFDM symbol output from the subcarrier interleave procedure changes even for the same transmission data sequence, and the maximum amplitude also changes. On the transmitting side, a plurality of subcarrier interleaving procedures #
Since subcarrier interleaving is performed by selecting a subcarrier interleaving procedure used for transmission from 1 to #N, the maximum amplitude of the time waveform of an OFDM symbol can be made relatively small.

On the receiving side, the OFDM symbol from receiving section 22 is applied to received OFDM signal receiving section 82, and a subcarrier sequence is obtained. This subcarrier sequence is provided to the identifier subcarrier detection unit 84, and the identifier subcarrier is detected. The identifier demodulated from the identifier subcarrier is provided to the subcarrier deinterleave procedure selection control unit 56, and a subcarrier deinterleave procedure corresponding to the subcarrier interleave on the transmission side is selected.

[0172] The subcarrier sequence from reception OFDM signal receiving section 82 is applied to subcarrier deinterleaving section 59, and is subjected to subcarrier deinterleaving according to a specified subcarrier deinterleaving procedure. Thus,
The subcarrier sequence in the original order is supplied to the demodulation unit 83, and a received digital data sequence is obtained.

The other operations are the same as those of the embodiment shown in FIGS.

As described above, in this embodiment, it is apparent that the same effects as those in the embodiment shown in FIGS. 6 and 8 can be obtained.

Although the transmitting side is described in a configuration having a plurality of subcarrier interleaving procedure storage units in parallel, a configuration in which a rearrangement table necessary for subcarrier interleaving is merely stored in a memory may be used. . The identifier indicating the subcarrier interleaving procedure does not need to indicate the rearrangement table itself, but may be a number or the like that represents a combination of the subcarrier interleaving procedure and the subcarrier deinterleaving procedure decided on the transmitting side and the receiving side. The receiving side forming a pair may have the same configuration as the transmitting side.

In the above-described embodiments of FIGS. 6 to 11, an example in which the identifier is transmitted by the subcarrier has been described. In this case, an additional method shown in the explanatory diagram of FIG. 12 can be considered. FIG. 12 shows an OFDM subcarrier to which an identifier subcarrier is added.

OF Modulating Subcarrier in Frequency Domain
In the DM transmission scheme, among a plurality of subcarriers constituting one OFDM signal, a subcarrier indicated by a solid line is modulated by a transmission data sequence, and a subcarrier indicated by a broken line is modulated by an identifier. For the identifier subcarrier,
By excluding the subcarrier interleaving, the identifier can be recognized on the receiving side.

Note that the number of identifier subcarriers is set to a number that can express the number of scrambling methods, the number of encoding methods, the number of bit interleaving procedures, and the number of subcarrier interleaving procedures prepared in advance in the transmitting / receiving apparatus. This number also depends on the subcarrier modulation method.

FIGS. 13 and 14 are charts showing examples of combinations in which a paired combination is transmitted between the transmitting side and the receiving side as identifiers. FIG. 13 shows an example in which ASK modulation is performed as subcarrier modulation, and FIG. 14 shows an example in which BPSK modulation is performed as subcarrier modulation. In addition, three subcarriers are used as identifiers.

For example, a scramble / descramble method, an encoding / decoding method, a bit interleave procedure / bit deinterleave procedure, a subcarrier interleave procedure / subcarrier deinterleave procedure having eight combinations in a transmitting / receiving apparatus are prepared. Shall be

In this case, three subcarriers are required to represent the ASK modulation subcarriers, as shown in FIG. 13, and the identifier is transmitted by ON / OFF of the subcarrier. The amplitude value and phase of the subcarrier do not matter at all. The identifier is transmitted with or without the subcarrier amplitude.

Further, as shown in FIG. 14, three subcarriers of BPSK modulation are used in the same manner as in ASK modulation.
It requires three subcarriers and transmits the identifier in the phase of three subcarriers. Of course, if multi-level PSK modulation is used, the number of subcarriers to be assigned to an identifier can be reduced, so that a transmission data sequence can be assigned to many subcarriers. For example, in the case of QPSK, if two subcarriers are used, 16 identifiers can be transmitted. Of course, if a high-efficiency modulation scheme such as QAM is used, many identifiers can be transmitted even with one subcarrier.

[0183]

As described above, according to the present invention, O
By suppressing the amplitude fluctuation of the FDM time waveform and improving the transmission average power, there is an effect that transmission errors at the time of data transmission can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing an embodiment of an OFDM signal transmission / reception method according to the present invention.

FIG. 3 is a flowchart showing one embodiment of an OFDM signal transmission / reception method according to the present invention.

FIG. 4 is a block diagram showing another embodiment of the present invention.

FIG. 5 is a block diagram showing another embodiment of the present invention.

FIG. 6 is a block diagram showing another embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating an embodiment.

FIG. 8 is a block diagram showing another embodiment of the present invention.

FIG. 9 is a block diagram showing another embodiment of the present invention.

FIG. 10 is a block diagram showing another embodiment of the present invention.

FIG. 11 is a block diagram showing another embodiment of the present invention.

FIG. 12 is an explanatory diagram illustrating an embodiment.

FIG. 13 is a table illustrating an embodiment.

FIG. 14 is a table illustrating an embodiment;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Scramble part, 11 # 1-11 # N ... Scramble sequence generation part, 14 ... Scramble method selection control part, 15 ... Scramble sequence selection part, 16 ... Identifier addition part, 24 ... Identifier detection part, 25 ... Descramble , 2
6 ... descrambling method selection control unit, 27 ... descrambling sequence selection unit, 28 # 1 to #N ... descrambling sequence generation unit

Claims (10)

[Claims] 1. A transmitting side of an OFDM signal transmitting and receiving radio station, on the transmitting side, selecting a transmitting process from a plurality of converting processes for converting a transmission data sequence into time waveforms of different OFDM symbols, and transmitting the selected transmitting process. A process of generating an OFDM signal; and a process of adding information indicating a conversion process used for the transmission to the transmission OFDM signal as an identifier, wherein the transmission side transmits and receives the OFDM signal. Receiving an OFDM signal, detecting the identifier, and selecting, based on the detected identifier, an inverse transform process corresponding to a transform process used for transmission from the plurality of inverse transform processes, and Converting the data into a transmission data sequence. 2. The conversion process used for the transmission is a process of multiplying one of a plurality of scramble sequences by the transmission data sequence. The inverse conversion process corresponding to the conversion process used for the transmission is performed by a plurality of processes. One of the descrambling sequences of
2. The OFDM signal transmitting / receiving method according to claim 1, wherein the method is a process of multiplying the digital data sequence obtained from a DM signal. 3. The conversion process used for the transmission is a process of applying one of a plurality of encoding methods to the transmission data sequence, and the inverse conversion process corresponding to the conversion process used for the transmission is: 2. The OFDM signal transmitting / receiving method according to claim 1, wherein the processing is one of applying one of a plurality of decoding methods to a digital data sequence obtained from the OFDM signal. 4. The conversion process used for the transmission is a process of performing bit interleaving on the transmission data sequence using one of a plurality of bit interleaving procedures, and corresponds to the conversion process used for the transmission. 2. The OFDM signal according to claim 1, wherein the inverse conversion process is a process of performing bit deinterleaving on a digital data sequence obtained from the OFDM signal using one of a plurality of bit deinterleaving procedures. Transmission / reception method. 5. The conversion process used for the transmission is a process of performing subcarrier interleaving on a subcarrier sequence obtained from the transmission data sequence using one of a plurality of subcarrier interleaving procedures. The inverse conversion process corresponding to the used conversion process is a process of performing subcarrier deinterleaving on a subcarrier sequence obtained from the OFDM signal using one of a plurality of subcarrier deinterleaving procedures. The OFDM signal transmission / reception method according to claim 1, wherein 6. The process according to claim 1, wherein, in the process of generating the transmission OFDM signal, when a retransmission request is generated from the receiving side, a conversion process different from that of the previous transmission is selected. OFDM signal transmission / reception method. 7. The method according to claim 1, wherein the identifier is added to the OFDM transmission signal by one or more binary bits. 8. The method according to claim 1, wherein the identifier is added to the OFDM transmission signal by one or more subcarriers. 9. The method according to claim 8, wherein the identifier is transmitted by a subcarrier modulated by any one of ASK modulation, PSK modulation, and QAM modulation. 10. A transmitting side among OFDM signal transmitting and receiving radio stations, on the transmitting side, selects a transmitting process from a plurality of converting processes for converting a transmission data sequence into time waveforms of different OFDM symbols, and transmits the selected transmitting process. An OFDM signal generating means for generating an OFDM signal; and an adding means for adding information indicating a conversion process used for the transmission to the transmission OFDM signal as an identifier, and a receiving side among wireless stations transmitting and receiving the OFDM signal. In the above, receiving the transmission OFDM signal, detecting means for detecting the identifier, based on the detected identifier, from a plurality of inverse conversion processing corresponding to the conversion process used for transmission and select an inverse conversion process, Means for converting a transmission OFDM signal into the transmission data sequence.