JP2002033715A - Multicarrier communication equipment and multicarrier communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the peak voltage of a signal using a simple configuration, without deteriorating transmission characteristics and making the equipment large in size. SOLUTION: A sequential coding processing section 102 applies class-4 partial response coding processing to serial data outputted from a digital modulation section 101 and expressed in binary values of '+1' and '0', to convert the serial data into serial data expressed in three values of '+1', '0' and '-1' and provides an output of the data to an SP conversion section 106. The SP conversion section 106 applies serial/parallel conversion to the serial data, assigns the respective data to a subcarrier and outputs the data to an IFFT (inverse fast-Fouirer transoframtion) section 107. The IFFT section 107 applies inverse fast-Fourier transformation to the signal outputted from the SP conversion section and outputs the transmission signal subjected to the inverse fast- Fourier transformation to a wireless transmission signal 108.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a communication apparatus and a communication method, and more particularly to a multicarrier communication apparatus and a multicarrier communication method.

[0002]

2. Description of the Related Art Conventionally, as a multi-carrier communication apparatus of this type and a method of suppressing peak power in the multi-carrier communication apparatus, there is a method described in Japanese Patent Application Laid-Open No. 7-143098.

FIG. 11 is a block diagram showing a configuration of a conventional multicarrier communication apparatus. The multi-carrier communication apparatus 11 shown in FIG.
, An S / P (Serial Parallel) converter 13 and an IFFT
(Inverse fast Fourier transform) unit 14, and the receiving side
FT (fast Fourier transform) unit 15 and P / S (Parallel
It comprises a serial (Serial) converter 16 and a digital demodulator 17.

In such a configuration, on the transmission side, the digital modulator 12 uses a BPSK (Binaripha
se Phase Shift Keying), 16QAM (Quadrature Am
Digital modulation based on transmission data is performed according to a modulation method such as Plitude Modulation.

[0005] The serial data after the modulation is S / P
In the converter 13, parallel data (digital symbols)
And the parallel data is converted to the IFFT unit 14
Then, by performing the inverse fast Fourier transform process, the signals are superimposed on subcarriers having different phases, and are output as time-sequentially continuous transmission OFDM symbol signals.

On the receiving side, the received OFDM symbol signal is subjected to fast Fourier transform processing by the FFT unit 15 to separate each data superimposed on subcarriers having different phases, and The parallel data is converted to serial data by a P / S converter 16 and the serial data is converted to a digital demodulator 17.
, And are digitally demodulated and output.

[0007]

However, in the conventional device, the transmission data is converted into parallel data and then transmitted by being superimposed on a plurality of subcarriers.
Since there is no correlation for each subcarrier, if the phases of the subcarriers overlap, an OFDM symbol has an extremely large signal amplitude.

As described above, if the peak voltage of a signal increases during transmission due to the overlapping of the subcarriers, when the signal is amplified by an amplifier, the peak portion of the signal is cut off according to the upper limit gain of the amplifier.

If a large-sized amplifier is used to prevent this, the overall size of the device is increased, and the power consumption is further increased.
There is a problem that heat generation is increased.

Here, as a method of suppressing the peak voltage, there is a method of setting an upper limit value of the voltage and simply cutting a voltage exceeding the upper limit value as described in Japanese Patent Application Laid-Open No. 7-143098. . However, simply cutting off the peak voltage distorts the signal and widens the band, which causes a problem that the error rate at the time of reception deteriorates (transmission characteristics deteriorate).

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made in consideration of the above-described problems. Accordingly, a multi-device capable of suppressing a peak voltage of a signal with a simple device configuration without deteriorating transmission characteristics and without increasing the size of the device. An object is to provide a carrier communication device and a multicarrier communication method.

[0012]

SUMMARY OF THE INVENTION A multicarrier communication apparatus according to the present invention performs a sequential coding in which an output amplitude of each of an in-phase component and a quadrature component of a signal to be transmitted includes zero in each output amplitude, and outputs a coded signal. And a first serial-to-parallel converter for serial-to-parallel conversion of the coded signal and outputting the converted signal.

[0013] In the multicarrier communication apparatus of the present invention, the sequential coding means transmits each of the in-phase component and the quadrature component of the signal to be transmitted using any one of pseudo ternary, duobinary, and partial response. A configuration for sequentially encoding signals is employed.

In the multicarrier communication apparatus according to the present invention, the sequential encoding means uses a partial response encoding system class 4 for delaying a signal to be encoded by a predetermined time and subtracting a signal to be encoded with the delayed signal. Thus, a configuration is adopted in which signals to be transmitted are sequentially encoded.

The multi-carrier communication apparatus according to the present invention comprises a second serial-parallel conversion means for serial-to-parallel conversion of a signal to be transmitted, a spreading means for multiplying the serial-parallel-converted signal by a spreading code, and a multiplication by the spreading code. And a first parallel-to-serial conversion unit for performing parallel-to-serial conversion into a signal, wherein the sequential coding unit sequentially codes the parallel-to-serial converted signal and outputs a coded signal.

[0016] The multicarrier communication apparatus of the present invention employs a configuration in which the spreading means distributes a spreading code to each subcarrier on a chip-by-chip basis and multiplies the signal of each subcarrier.

According to these configurations, a signal to be transmitted is sequentially encoded to reduce the number of symbols having the same phase on subcarriers, thereby reducing the transmission characteristics and increasing the size of the apparatus. Therefore, the peak voltage of the signal can be suppressed with a simple device configuration.

The multi-carrier communication apparatus according to the present invention is a second parallel-to-serial conversion means for performing parallel-to-serial conversion on a coded signal transmitted by performing sequential coding including an output amplitude of 0 for each of the in-phase component and the quadrature component. And a sequential decoding unit that performs sequential decoding, which is an inverse process of the sequential encoding, on the parallel-serial converted signal and outputs a decoded signal.

The multicarrier communication apparatus according to the present invention employs a configuration in which the successive decoding means decodes a signal in which the in-phase component and the quadrature component have been sequentially coded including the output amplitude of 0.

The multicarrier communication apparatus according to the present invention employs a configuration in which the successive decoding means adds an encoded signal to a signal decoded in the past.

The multicarrier communication apparatus according to the present invention employs a configuration in which the sequential decoding means adds a signal encoded by the partial response encoding method class 4 to a signal decoded in the past.

According to these configurations, a signal to be transmitted is sequentially encoded to reduce the number of symbols having the same phase on subcarriers, thereby reducing the transmission characteristics and increasing the size of the apparatus. Without using a simple device configuration, a signal in which the peak voltage of the signal is suppressed can be received and decoded.

In the multicarrier communication apparatus according to the present invention, the maximum likelihood decoding means subtracts a received signal from a replica signal obtained by sequentially encoding candidate signals that may have been transmitted,
A configuration is adopted in which the obtained error signal is squared, and a candidate signal having the smallest obtained inter-signal distance information is selected and output.

According to this configuration, a signal to be transmitted is sequentially encoded to reduce the number of symbols having the same phase on subcarriers, thereby reducing the transmission characteristics and increasing the size of the apparatus. In addition, a signal in which the peak voltage of the signal is suppressed can be received and decoded with high accuracy using a simple device configuration.

The multicarrier communication apparatus according to the present invention comprises: third serial / parallel conversion means for serial-to-parallel conversion of a signal output from the sequential decoding means; and despreading means for multiplying the serial / parallel converted signal by a spreading code. ,
And a third parallel-serial conversion means for performing parallel-serial conversion on the signal multiplied by the spread code.

The multicarrier communication apparatus of the present invention employs a configuration in which the despreading means duplicates a spreading code for each subcarrier in chip units and multiplies the signal of each subcarrier.

According to these configurations, a signal to be transmitted is sequentially encoded to reduce the number of symbols having the same phase on subcarriers, thereby reducing the transmission characteristics and increasing the size of the apparatus. Without using a simple device configuration, a signal in which the peak voltage of the signal is suppressed can be received and decoded.

The base station communication apparatus of the present invention employs a configuration including any one of the above-described multicarrier communication apparatuses.

A communication terminal device according to the present invention employs a configuration including any one of the multicarrier communication devices described above.

According to these configurations, a signal to be transmitted is sequentially encoded, and the number of symbols having the same phase on subcarriers is reduced to thereby reduce the transmission characteristics and increase the size of the apparatus. Therefore, the peak voltage of the signal can be suppressed with a simple device configuration.

According to the multicarrier communication method of the present invention, a signal to be transmitted is converted to an in-phase component and a quadrature component by an output amplitude of zero.
A sequential encoding step of outputting a coded signal, a first serial-parallel conversion step of serial-parallel-converting and transmitting the coded signal, and receiving the transmitted coded signal. A second parallel-to-serial conversion step of performing parallel-to-serial conversion, and setting the output amplitude to 0
And a sequential decoding step of sequentially decoding a signal that has been subjected to sequential coding and outputting a decoded signal.

According to this method, a signal to be transmitted is sequentially encoded to reduce the number of symbols of the same phase on subcarriers, thereby reducing the transmission characteristics and increasing the size of the apparatus. And the peak voltage of the signal can be suppressed.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a sequential coding technique, a signal containing "0" in its amplitude is created.

In the multi-carrier communication, a signal is distributed to a plurality of sub-carriers, multiplied by a sub-carrier frequency, and the obtained signal is synthesized and transmitted. When transmitting, the transmission power increases.

The inventor of the present invention performs a sequential encoding process on a signal to be transmitted in multicarrier communication to generate a signal including an amplitude “0” and to generate a subcarrier not to be transmitted. Focusing on the fact that the transmission voltage is reduced, it has been found that the peak voltage of the transmission signal in multicarrier communication is suppressed by performing sequential coding processing on the signal to be transmitted, distributing the signal in the frequency domain, and transmitting the signal.

That is, the gist of the present invention is to sequentially encode a signal in the subcarrier direction, generate a signal having an amplitude of “0”, and distribute this signal to each subcarrier, thereby obtaining each signal. It is to suppress the peak voltage of the transmission signal by reducing the possibility and the number of overlapping phases of the subcarrier signals.

Hereinafter, according to the embodiment of the present invention, the partial response encoding method class 4
This will be described in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a multicarrier communication apparatus according to Embodiment 1 of the present invention.

In FIG. 1, a digital modulation unit 101
The transmission data is digitally modulated, and the modulated serial data is sequentially output to the encoding processing unit 102.

The sequential encoding unit 102 includes a delay unit 103
, A delay unit 104, and an adder 105.

The sequential encoding processing unit 102 performs a class 4 partial response encoding process on the binary data "+1" and "0" output from the digital modulation unit 101, and performs "+1" The data is converted into serial data represented by three values of “0” and “−1” and output to the SP conversion unit 106.

The class 4 partial response encoding process is realized by subtracting the input signal delayed by two periods from the input signal. A specific example will be described later.

The delay unit 103 delays the serial data output from the digital modulation unit 101 for a predetermined time, for example, one cycle, and outputs the serial data to the delay unit 104.

The delay unit 104 delays the input serial data by a predetermined time, for example, one cycle, and outputs the serial data to the adder 105.

The adder 105 subtracts the serial data output from the delay unit 104 with the serial data output from the digital modulation unit 101, and outputs the obtained serial data to the SP conversion unit 106.

The SP conversion unit 106 includes a sequential encoding unit 1
The serial data output from the C.O.T. 02 is subjected to serial-parallel conversion, each data is allocated to a subcarrier, and output to the IFFT unit 107.

IFFT section 107 performs inverse fast Fourier transform on the signal output from the SP transform section, and outputs a transmission signal after inverse Fourier transform to radio transmitting section 108.

Radio transmission section 108 converts the transmission signal from digital to analog and up-converts it,
Is transmitted as a wireless signal via the.

[0049] Antenna 109 transmits the transmission signal output from radio transmission section 108, and outputs the received radio signal to radio reception section 110 as a reception signal.

Radio receiving section 110 down-converts the received signal into an analog signal, and outputs the signal to FFT section 111.

FFT section 111 performs a fast Fourier transform on the received signal and outputs it to PS conversion section 112.

The PS conversion unit 112 converts the received signal from parallel to serial, combines the signals of the respective subcarriers into serial data, and outputs the serial data to the sequential decoding processing unit 113.

The sequential decoding unit 113 includes an adder 114
, A delay unit 115, and a delay unit 116.

The sequential decoding processing unit 113 includes the PS conversion unit 1
A class 4 partial response decoding process is performed on the serial signal on which the ternary information of “+1”, “0”, and “−1” is output, and the serial signal on which the binary information of “+1” and “0” is added is output. The signal is converted to a signal and output to the digital demodulation unit 117.

The class 4 partial response decoding process is realized by delaying the signal subjected to the addition process in the past by two periods and adding the delayed signal to the input signal. A specific example will be described later.

The adder 114 adds the serial signal output from the delay unit 116 described later to the serial signal output from the SP conversion unit 112, and outputs the obtained serial signal to the digital demodulation unit 117 and the delay unit 115. Output.

The delay unit 115 delays the input serial signal by a predetermined time, for example, one cycle, and outputs the delayed signal to the delay unit 116.

The delay unit 116 delays the input serial signal by a predetermined time, for example, one cycle, and outputs the serial signal to the adder 114.

Digital demodulation section 117 demodulates the serial signal output from sequential decoding processing section 113 and outputs received data.

Next, with reference to FIG.
02 shows an example in which partial response class 4 encoding processing is performed on input data to generate an amplitude “0”.

In FIG. 2, 12-bit input data "1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0"
Is subtracted from the input data delayed by 2 bits in the sequential coding processing unit 102, and the ternary data “1, 1, 0, 0, 0, 0, 0, 0, −1, -1 ".

In the conventional encoding process, this 12-bit input data is expressed as “1, 1, 1, 1, 1, 1, 1, 1, 1, −
1, -1, -1, -1 ", and this data is distributed to four subcarriers. When the first 4-bit data “1, 1, 1, 1” is distributed to four subcarriers, symbols of the same phase overlap on each subcarrier, so that transmission power increases.

The subsequent data “1, 1, 1, 1” and “−”
In the case of “1, −1, −1, −1”, the transmission power increases because symbols of the same phase overlap with the four subcarriers.

However, in the multi-carrier communication apparatus of the present invention, the first 4-bit data “1, 1, 0, 0” that has been subjected to the sequential encoding process is distributed to four subcarriers.

Here, “0” is a symbol whose amplitude is “0”, and only two symbols of the phase “1” overlap in four subcarriers, compared with the above-mentioned example in which the same symbol overlaps four. The transmission power is halved, and an increase in transmission power can be suppressed.

The subsequent data “0, 0, 0, 0” and “0, 0, −1, −1” also have the same number of symbols of the same phase overlapping four subcarriers, as compared with the conventional device. Thus, an increase in transmission power can be suppressed.

This data contains data of amplitude “0”, and the subcarriers to which symbols of amplitude “0” are distributed have transmission power of “0”. In class 4 partial response coding, since half of the symbols are statistically “0”, the amplitude of half of the symbols distributed to the subcarriers is also “0”, and the subcarrier symbols are combined. The power of the transmitted transmission signal is also halved.

As described above, according to the multicarrier communication apparatus of the present embodiment, a signal to be transmitted is sequentially encoded,
By reducing the number of overlapping symbols of the same phase on the subcarrier, the peak voltage of the signal can be suppressed with a simple device configuration without deteriorating the transmission characteristics and increasing the size of the device.

Further, according to the multicarrier communication apparatus of the present embodiment, the above signal can be received and decoded.

(Embodiment 2) FIG. 3 is a diagram showing a configuration of a receiving portion of a multicarrier communication apparatus according to Embodiment 2 of the present invention.

FIG. 3 shows an example in which partial response coding system class 4 coding is used in the sequential coding process.

Multiplying section 301-1 multiplies the received signal by subcarrier frequency f1 and performs LPF (Low Pass Filtration).
r) Output to 302-1.

Similarly, multiplication units 301-2 to 301-4
Are the subcarrier frequencies f2 to f
4 and LPF 302-2 to LPF 3 respectively.
02-4.

LPF 302-1 integrates the received signal in one symbol time to obtain a received symbol, and outputs the obtained received symbol to PS conversion section 303.

Similarly, LPF 302-2 and LPF 302
-3 and LPF 302-4 integrate the received signal in one symbol time to obtain a received symbol, and output the obtained received symbol to PS conversion section 303.

[0076] PS conversion section 303 performs parallel-to-serial conversion on the received symbols and outputs the obtained serial data to maximum likelihood decoding section 304.

The maximum likelihood decoding section 304 includes the data string generating section 31
1, an encoding unit 312, an addition / subtraction unit 313, and a square unit 3
14 and a path selection unit 315.

The data sequence generator 311 generates a symbol sequence that may have been transmitted (hereinafter, referred to as a “candidate symbol sequence”), and encodes the sequencer 312 and the path selector 315.
Output to

The encoding section 312 performs partial response encoding on the candidate symbol sequence, and outputs the obtained replica signal to the addition / subtraction section 313.

The addition / subtraction unit 313 outputs an error signal obtained by subtracting the replica signal from the received signal to the square unit 314.

The squaring unit 314 squares the error signal, calculates a branch metric representing the inter-signal distance, and outputs the result to the path selection unit 315.

The path selecting section 315 includes the data string generating section 31
A candidate symbol sequence corresponding to the replica signal sequence having the smallest path metric from the replica signal output from 1 is output as a hard-decision received symbol sequence. Further, path selection section 315 outputs a branch metric sequence of the replica signal having the smallest path metric as received symbol likelihood information.

Next, the receiving operation of the multicarrier communication apparatus according to the present embodiment will be described.

The input received signal is multiplied by a multiplication section 301-1.
Are multiplied by a subcarrier frequency in a multiplication unit 301-4, and are then separated as received symbols into subcarriers through LPFs 302-1 to LPF 302-4.

The received symbol is subjected to parallel-serial conversion in PS conversion section 303 and output to addition / subtraction section 313 of the maximum likelihood decoding section as a received symbol sequence.

The candidate symbol sequence is output from the data sequence generation unit 311.
The generated replica signal is output to the encoding unit 312 and subjected to partial response encoding, and the obtained replica signal is output to the addition / subtraction unit 313.

The received symbol sequence is subtracted by the replica signal in addition / subtraction section 313, and the obtained error signal is output to squaring section 314.

The error signal is squared in the squarer 314 and the obtained branch metric is converted to the path selector 3.
15 is output.

The branch metric is calculated by the path selection unit 315.
, A candidate symbol sequence corresponding to the replica signal sequence having the smallest path metric is output as a hard-decision reception symbol. The branch metric sequence of the replica signal having the smallest path metric is output as received symbol likelihood information.

The branch metric for the data sequence selected by the maximum likelihood decoding indicates the likelihood of each output symbol, and can be used for error correction at a subsequent stage.

As described above, according to the multicarrier communication apparatus of the present embodiment, signals to be transmitted are sequentially encoded,
By reducing the number of overlapping symbols of the same phase on the subcarrier, it is possible to receive a signal in which the peak voltage of the signal is suppressed with a simple device configuration without deteriorating the transmission characteristics and without increasing the size of the device. And can be decoded with high accuracy.

(Embodiment 3) FIG.4 is a diagram showing a configuration of a transmission part of a multicarrier communication apparatus according to Embodiment 3 of the present invention.

Hereinafter, the multi-carrier communication apparatus performs code multiplexing by multiplying signals to a plurality of users by different spreading codes, respectively, and performs partial response coding system class 4 of the partial response coding method in the sequential coding processing of the code multiplexed signal. An example using encoding will be described. Note that the number of users is shown as two.

In FIG. 4, a duplicating section 411-1 duplicates an input transmission symbol, and demultiplexes the despreading section 412-11.
To the despreading section 412-14, and outputs the copied transmission symbols.

The duplicating section 411-2 duplicates the input transmission symbol, and demultiplexes the despreading sections 412-21 to 412.
The duplicate transmission symbols are output to 2-24.

Despreading units 412-11 to 412-412
14 multiplies the transmission symbol by a code output from a code distribution unit 413-1 described later,
14-1.

Despreading units 412-21 to 412-412
24 multiplies the transmission symbol by a code output from a code distribution unit 413-2, which will be described later,
14-2.

The code distribution section 413-1 duplicates the spread code in chip units and despreads the despread sections 412-11 to 41-11.
Output to 2-14.

The code distribution unit 413-2 duplicates the spread code in chip units and despreads the despread units 412-21 to 412-21.
Output to 2-24

The PS conversion section 414-1 outputs serial data obtained by parallel-to-serial conversion of a transmission symbol to the offset addition section 415-1.

PS conversion section 414-2 outputs serial data obtained by parallel-to-serial conversion of a transmission symbol to offset adding section 415-2.

The offset adding sections 415-1 and 415-2 output the serial data "+1",
The two values “−1” are converted into two values “1” and “0”, and the respective outputs are output to the adder 416.

The adder 416 has an offset adding section 415
-1 and the serial data output from the offset adding section 415-2 are added and output to the partial response encoding section 417.

The partial response encoding section 417
The serial data synthesized by the adder 416 is encoded, and the serial data represented by three values of “+2”, “+1”, and “0” are converted to “+2”, “+1”, “0”, “−1”, and “−2”.
Is converted to serial data represented by the five values and output to the SP converter 418.

[0105] SP conversion section 418 converts the serial data from serial to parallel, distributes it as a transmission symbol to each subcarrier, and outputs the transmission symbols to multiplication sections 419-1 to 419-4.

The multipliers 419-1 to 419-4 are:
The transmission symbol is multiplied by each of the subcarrier frequencies f1 to f4 and output to combining section 420.

Combining section 420 adds the transmission symbols output from multiplying section 419 and transmits the sum.

Next, the operation of the multicarrier communication apparatus will be described.

The input transmission symbol sequence S1 is converted into a despreading unit 412-
11 to the despreading section 412-14 to output the duplicated transmission symbol sequence. The input transmission symbol sequence S2 is
The despreading unit 4 of each subcarrier in the duplication unit 411-2
12-21 to the despreading section 412-24, and outputs the duplicated transmission symbol sequence.

The transmission symbol sequence output from replicating section 411-1 is converted into despreading section 412-11 and despreading section 412-1.
2. Despreading unit 412-13 and despreading unit 412-14
Are multiplied by the code output from the code distribution unit 413-1 and output to the PS conversion unit 414-1. The PS conversion unit 414-1 performs parallel-serial conversion and outputs the result to the offset addition unit 415-1.

The transmission symbol sequence output from duplicating section 411-2 is applied to despreading section 412-21 and despreading section 412-2.
2. Despreading unit 412-23 and despreading unit 412-24
Are multiplied by the code output from the code distribution unit 413-2, output to the PS conversion unit 414-2, converted to parallel / serial by the PS conversion unit 414-2, and output to the offset addition unit 415-2.

In the transmission symbol, two values of “+1” and “−1” are converted into two values of “1” and “0” in offset adding section 415-1 and offset adding section 415-2, respectively. I do.

The signals output from the offset adding sections 415-1 and 415-2 are added to the adder 41.
6 and output to the partial response encoding unit 417.

In the partial response encoding unit 417, from the transmission symbol represented by the three values of “+2”, “1” and “0”, “5” of “+2”, “+1”, “0”, “−1” and “−2” are obtained.
The data is encoded into serial data represented by a value and output to the SP conversion unit 418.

The serial data is subjected to serial / parallel conversion in SP conversion section 418 and distributed to each subcarrier.

The symbols distributed to the subcarriers are multiplied by the subcarrier frequencies in multipliers 419-1 to 419-4, the symbols are added in combiner 420, and the resulting transmission signal is transmitted. .

This serial data contains data of amplitude “0”, and the subcarriers to which symbols of amplitude “0” are distributed have transmission power “0” and amplitude “0”. Since the symbols are included in the subcarriers, the peak voltage of the transmission signal that is output by combining the symbols of the subcarriers can also be suppressed.

FIG. 5 is a diagram showing a configuration of a receiving portion of a multicarrier communication apparatus according to Embodiment 3 of the present invention.
However, components having the same configuration as in FIG. 3 are denoted by the same reference numerals, and detailed description is omitted.

FIG. 5 shows an example in which partial response coding system class 4 coding is used for the sequential coding process. Note that the number of users is shown as two.

In FIG. 5, PS conversion section 303 converts the received symbol from parallel to serial, and outputs the obtained serial data to partial response decoding section 504.

[0121] The partial response decoding unit 504
A class 4 partial response decoding process is performed on a serial signal carrying quinary information of “+2”, “+1”, “0”, “−1”, and “−2” to obtain three values of “+2”, “+1”, and “0”. The information is converted into a serial signal carrying the information, and the offset is removed.
05-1 and the offset removing unit 505-2.

The offset removing section 505-1 outputs "+2".
The serial signal carrying the ternary information of "+1" and "0" is expressed as "+
The signal is converted into a serial signal carrying ternary information of “2”, “0”, and “−2” by level shift and output to the SP conversion unit 506-1. Further, the offset removing unit 505-2 outputs “+2”.
The serial signal carrying the ternary information of "+1" and "0" is expressed as "+
The signal is converted by a level shift into a serial signal carrying ternary information of "2", "0" and "-2" and output to the SP converter 506-2.

[0123] SP conversion section 506-1 converts the serial signal from serial to parallel, distributes it as a received symbol for each subcarrier, and outputs it to despreading sections 507-11 to 507-14. Also, the SP conversion unit 506-2
Performs serial-to-parallel conversion of a serial signal, distributes it as a received symbol for each subcarrier, and
7-21 to the despreading unit 507-24.

Despreading sections 507-11 to 507-
Reference numeral 14 designates a received symbol as a spread code distributing section 50 to be described later.
Each of the spreading codes output from 8-1 is multiplied by one chip and output to the combining unit 509-1. Further, despreading sections 507-21 to 507-24 multiply the received symbols by one chip each with a spread code output from spread code distribution section 508-2, which will be described later, and synthesizer. 509-2.

Spreading code distribution section 508-1 spreads the spreading code into despreading sections 507-11 to 507-11 of each subcarrier.
The output is distributed to the chip 7-14 in chip units. The spreading code distribution unit 508-2 distributes the spreading code to the despreading units 507-21 to 507-24 of each subcarrier in chip units and outputs the result.

The synthesizing section 509-1 includes a despreading section 507-1.
1 to add-synthesize the received symbols output from despreading section 507-14 and output as a received symbol sequence. Also, combining section 509-2 adds and combines the received symbols output from despreading sections 507-21 to 507-24, and outputs the resultant as a received symbol sequence.

Next, the operation of the multicarrier communication apparatus will be described. The received signals are supplied to the multipliers 301-1 to 3
01-4, are multiplied by the respective subcarrier frequencies f1 to f4, are separated into respective subcarriers as received symbols through the LPFs 302-1 to 302-4, output to the PS converter 303, are subjected to parallel / serial conversion, and are obtained as serial data. The signal is a partial response decoding unit 5
04 is output.

In the partial response decoding unit 504, a serial signal in which ternary information of “+1”, “−1”, and “0” is added is converted into a serial signal in which binary information of “1” and “0” is added. Converted, offset removing unit 50
In 5-1, the serial signal carrying the two information of "1" and "0" is converted into a serial signal carrying the information of "+1" and "-1", and is subjected to serial / parallel conversion in the SP converter 506-1. Each of the subcarriers is distributed as a received symbol to despreading sections 507-11 to 507-14.

The serial signal is converted into "+2", "+1", "0" by the partial response decoding unit 504.
The serial signal carrying the ternary information "-1" and "-2" is converted into a serial signal carrying the ternary information "2", "1", and "0", and the offset removing unit 505-2 converts "2"
The serial signal carrying the ternary information of “1” and “0” is “+”
The signal is converted into a serial signal carrying ternary information of "2", "0", and "-2", and is subjected to serial / parallel conversion in the SP converter 506-2. It is distributed to the diffusion units 507-24.

The received symbols output from SP conversion section 506-1 are supplied to despreading sections 507-11 to 507-
After the multiplication by the code output from the spreading code distribution unit 508-1 at 14, the output is output to the combining unit 509-1, and the received symbols of each subcarrier are added and combined by the combining unit 509-1 to obtain A received symbol sequence is output.

The received symbols output from SP conversion section 506-2 are converted into despreading sections 507-21 to 507-507.
After being multiplied by the code output from the spreading code distribution unit 508-2 in 24, the multiplication result is output to the combining unit 509-2, and the received symbols of the subcarriers are added and combined in the combining unit 509-2, and are obtained. A received symbol sequence is output.

As described above, according to the multicarrier communication apparatus of the present embodiment, a signal to be transmitted is sequentially encoded,
By reducing the number of overlapping symbols of the same phase on the subcarrier, the peak voltage of the signal can be suppressed with a simple device configuration without deteriorating the transmission characteristics and increasing the size of the device.

Further, according to the multicarrier communication apparatus of the present embodiment, the above signal can be received and decoded.

(Embodiment 4) FIG. 6 is a diagram showing a configuration of a receiving portion of a multicarrier communication apparatus according to Embodiment 4 of the present invention. However, components having the same configuration as that of FIG. 3 or FIG. 5 are denoted by the same reference numerals as those of FIG. 3 or FIG. FIG. 6 shows an example in which the encoding of the partial response encoding system class 4 is used in the sequential encoding process. Note that the number of users is shown as two.

In FIG. 6, PS conversion section 303 performs parallel-to-serial conversion on the received symbols and outputs the obtained serial signal to multi-level maximum likelihood decoding section 604.

Multi-valued maximum likelihood decoding section 604 generates a candidate symbol sequence corresponding to the input number of multiplex users, performs partial response encoding on the candidate symbol sequence,
The obtained replica signal is compared with the received signal, and the obtained replica candidate symbol sequence having the smallest inter-signal distance is output as a hard-decision received symbol sequence. Further, M-ary maximum likelihood decoding section 604 uses the branch metric sequence corresponding to the candidate symbol sequence output as the hard decision received symbol sequence as offset symbol likelihood information to offset removing section 505-1 and offset removing section 505-2. Output.

FIG. 7 is a main block diagram showing a detailed configuration of multi-level maximum likelihood decoding section 604.

In FIG. 7, multi-level maximum likelihood decoding section 604
It comprises a data sequence generator 605, a sequential encoder 606, an adder / subtractor 607, a squarer 608, and a path selector 609.

The data sequence generator 605 generates a symbol sequence of n values (hereinafter, referred to as a “candidate symbol sequence”) corresponding to the input user number n and possibly transmitted, and sequentially encodes the sequence. And a path selection unit 609.

[0140] Successive coding section 606 performs partial response filtering on the candidate symbol sequence, and outputs the obtained replica signal to addition / subtraction section 607.

[0141] Addition / subtraction section 607 outputs an error signal obtained by subtracting the replica signal from the received signal to squaring section 608.

The squaring unit 608 squares the error signal, calculates a branch metric representing the distance between the signals, and outputs the result to the path selection unit 609.

The path selecting section 609 includes the data string generating section 60
The candidate symbol sequence corresponding to the replica signal sequence having the smallest path metric from the replica signals output from 5 is output as a hard-decision received symbol sequence. Further, path selecting section 609 outputs a branch metric sequence of the replica signal having the smallest path metric as received symbol likelihood information.

As described above, according to the multicarrier communication apparatus of the present embodiment, signals to be transmitted are sequentially encoded,
By reducing the number of overlapping symbols of the same phase on the subcarrier, it is possible to receive a signal in which the peak voltage of the signal is suppressed with a simple device configuration without deteriorating the transmission characteristics and without increasing the size of the device. And can be decoded with high accuracy.

The transmission symbol sequence S1 and the transmission symbol sequence S2 can multiplex transmission data of two communication partners.

Further, the transmission symbol sequence S1 and the transmission symbol sequence S2 can also multiplex two transmission data of one communication partner.

In the description of the present embodiment, an example is described in which two symbol sequences are multiplexed and communicated.
It is also possible to spread and multiplex two or more symbol sequences with a spreading code for communication.

(Embodiment 5) FIG. 8 is a diagram showing a configuration of a transmission section of a multicarrier communication apparatus according to Embodiment 5 of the present invention. FIG. 8 shows an example in which partial response coding method class 4 coding is used for the sequential coding process. Note that the number of users is shown as two.

In FIG. 8, spreading section 703-1 multiplies transmission symbol sequence S1 by spreading code P1 and outputs the result to offset adding section 704-1.

Spreading section 703-2 multiplies transmission symbol sequence S 2 by spreading code P 2, and adds offset adding section 704-4.
Output to 2.

The offset adding section 704-1 sets the two values of the serial data “+1” and “−1” to “1”,
The value is converted into two values “0” and output to the adder 705.

The offset adding section 704-2 converts the two values of the serial data “+1” and “−1” into “1”,
The value is converted into two values “0” and output to the adder 705.

The adder 705 includes an offset adding section 704
-1 and the serial data output from the offset adding unit 704-2 are added and output to the partial response encoding unit 706.

The partial response encoding unit 706 is
Encodes serial data to "+1", "-1", "0"
, And outputs it to the SP converter 707.

[0155] SP conversion section 707 performs serial-to-parallel conversion on the serial data, distributes the data to each subcarrier as a transmission symbol, and outputs the transmission symbols to multiplication sections 708-1 to 708-4.

The multiplication units 708-1 to 708-4 are
The transmission symbol is multiplied by each subcarrier frequency and output to addition section 709.

Addition section 709 adds the transmission symbols output from the multiplication section and transmits the result.

Next, the operation of the multicarrier communication apparatus will be described. The input transmission symbol sequence S1 is multiplied by spreading code P1 in spreading section 703-1 and output to offset adding section 704-1. The input transmission symbol sequence S2 is multiplied by the spreading code P2 in the spreading section 703-2 and output to the offset adding section 704-2.

The transmission symbols output from spreading section 703-1 and spreading section 703-2 are applied to offset adding section 704.
In the −1 and offset adding section 704-2, “+
The two values “1” and “−1” are converted into two values “1” and “0” and then added in the adder 705, output to the partial response encoding unit 706, and output to the partial response encoding unit Encoded at 706,
SP is converted from serial data represented by three values of "2", "1", and "0" to five values of "+2", "+1", "0", "-1", and "-2". Output to conversion section 707.

[0160] The serial data is subjected to serial / parallel conversion in SP conversion section 707 and distributed to each subcarrier.

The symbols distributed to the subcarriers are multiplied by the subcarrier frequencies in multipliers 708-1 to 708-4, the symbols are added in adder 709, and the obtained transmission signal is transmitted. .

The transmission symbols distributed to the subcarriers include data of amplitude “0”, and the subcarriers to which the symbols of amplitude “0” are distributed have transmission power of “0”.

In class 4 partial response coding, since half of the symbols are statistically “0”, the amplitude of half of the symbols distributed to the subcarriers is also “0”, and The power of the transmission signal that combines and outputs the symbols also becomes １ ／.

FIG. 9 is a diagram showing a configuration of a receiving portion of a multicarrier communication apparatus according to Embodiment 5 of the present invention.

In FIG. 9, PS conversion section 303 performs parallel-to-serial conversion on the received symbol and outputs the obtained serial data to partial response decoding section 804.

The partial response decoding unit 804
A class 4 partial response decoding process is performed on a serial signal carrying quinary information of “+2”, “+1”, “0”, “−1”, and “−2” to obtain three values of “2”, “1”, and “0”. The information is converted into a serial signal carrying the information, and the offset is removed by the offset removing unit 805.
-1 and output to the offset removing unit 805-2.

The offset removing section 805-1 sets "2".
The serial signal carrying the ternary information of “1” and “0” is expressed as “+
The signal is converted into a serial signal carrying ternary information of "2", "0", and "-2", and output to the SP converter 806-1.

The offset removing unit 805-2 sets "2".
The serial signal carrying the ternary information of “1” and “0” is expressed as “+
The signal is converted into a serial signal carrying ternary information of "2", "0", and "-2", and output to the SP converter 806-2.

The SP conversion section 806-1 converts the serial signal from serial to parallel, distributes the received signal as a received symbol for each subcarrier, and matches the matched filter 807-11 to 807-11.
Output to the matched filter 807-14.

[0170] SP conversion section 806-2 converts the serial signal from serial to parallel, distributes it as received symbols for each subcarrier, and matches matched filters 807-21 to 807-21.
Output to the matched filter 807-24.

[0171] Matched filter 807-11 finds the correlation between the received symbol and the spreading code, makes a hard decision on the peak amplitude, despreads the received symbol, and outputs the obtained received symbol to PS conversion section 808-1. I do.

Similarly, a matched filter 807-12, a matched filter 807-13, and a matched filter 8
07-14 calculates the correlation between the received symbol and the spreading code, hard-decides the peak amplitude, and despreads the received symbol.
The obtained received symbols are output to PS conversion section 808-1.

The PS conversion section 808-1 outputs a received symbol sequence obtained by performing parallel-to-serial conversion on the received symbols output from the matched filters 807-11 to 807-14.

The PS conversion section 808-2 outputs a received symbol sequence obtained by performing parallel / serial conversion on the received symbols output from the matched filters 807-21 to 807-24.

Next, the operation of the multicarrier communication apparatus will be described.

The received signals are supplied to multiplication units 301-1 to 3
01-4, are multiplied by the respective subcarrier frequencies f1 to f4, are separated into respective subcarriers through the LPFs 302-1 to 302-4 as reception symbols, output to the PS converter 303, are subjected to parallel / serial conversion, and are obtained as serial data. The data is output to partial response decoding section 804.

The partial response decoding unit 804 converts the serial data into “+2”, “+1”, “0”, “−”.
The serial signal carrying the ternary information of "1" and "-2" is converted into the serial signal carrying the ternary information of "2", "1" and "0", and the offset removing unit 805-1 converts the signal of "2"
The serial signal carrying the ternary information of “1” and “0” is “+”
The signal is converted into a serial signal carrying ternary information of "2", "0", and "-2", and is subjected to serial-to-parallel conversion in the SP conversion unit 806-1. Filter 80
Distributed to 7-14.

The partial response decoding unit 804 converts the serial data into “+2”, “+1”, and “0”.
The serial signal carrying the ternary information "-1" and "-2" is converted into the serial signal carrying the ternary information "2", "1" and "0", and the offset removing unit 805-2 converts the signal "2".
The serial signal carrying the ternary information of “1” and “0” is “+”
The signal is converted into a serial signal carrying ternary information of "2", "0", and "-2", and is subjected to serial-to-parallel conversion in the SP converter 806-2. Filter 80
7-24 are distributed.

The received symbol output from SP conversion section 806-1 is despread by matched filter 807-11 to matched filter 807-14 by hard-deciding the peak amplitude of the correlation with the spreading code. The obtained received symbols are output to PS conversion section 808-1.

The received symbols output from SP conversion section 806-2 are despread by matched filter 807-21 to matched filter 807-24 making a hard decision on the peak amplitude of the correlation with the spreading code. The obtained received symbols are output to PS conversion section 808-2.

The received symbols despread in matched filters 807-11 to 807-14 are subjected to parallel-serial conversion in PS conversion section 808-1, and the resulting received symbol sequence is output.

The received symbols despread in matched filters 807-21 to 807-24 are subjected to parallel / serial conversion in PS conversion section 808-2, and the obtained received symbol sequence is output.

As described above, according to the multicarrier communication apparatus of the present embodiment, signals to be transmitted are sequentially encoded,
By reducing the number of overlapping symbols of the same phase on the subcarrier, the peak voltage of the signal can be suppressed with a simple device configuration without deteriorating the transmission characteristics and increasing the size of the device.

Further, according to the multicarrier communication apparatus of the present embodiment, the above signal can be received and decoded.

(Embodiment 6) FIG.10 is a diagram showing a configuration of a receiving portion of a multicarrier communication apparatus according to Embodiment 6 of the present invention. However, components having the same configuration as in FIG. 3 or FIG. 9 are denoted by the same reference numerals as in FIG. 3 or FIG. 9, and detailed description is omitted.

In FIG. 10, PS conversion section 303 performs parallel-to-serial conversion on the received symbol and outputs the obtained serial signal to multi-level maximum likelihood decoding section 904.

Multi-valued maximum likelihood decoding section 904 generates a candidate symbol string corresponding to the number of input multiplexed users, performs partial response coding on the generated candidate symbol string, and obtains the obtained replica signal and received signal. And outputs the replica candidate symbol sequence with the smallest inter-signal distance as a hard-decision received symbol sequence. Also, the multi-level maximum likelihood decoding unit 9
No. 04 outputs the branch metric sequence corresponding to the candidate symbol sequence output as the hard-decision received symbol sequence to the offset removing unit 805-1 and the offset removing unit 805-2 as received symbol likelihood information.

As described above, according to the multicarrier communication apparatus of the present embodiment, signals to be transmitted are sequentially encoded,
By reducing the number of overlapping symbols of the same phase on the subcarrier, it is possible to receive a signal in which the peak voltage of the signal is suppressed with a simple device configuration without deteriorating the transmission characteristics and without increasing the size of the device. And can be decoded with high accuracy.

In this embodiment, the case where the signal is BPSK-modulated has been described. However, the present invention is not limited to this.
And the like can be applied to multi-level modulation. In this case, it can be realized by replacing the device components with complex numbers.

The present invention is also applicable to multi-level modulation such as 16QAM, 64QAM and the like.

Further, for the sequential encoding, an encoding method that includes an amplitude of 0 in the output of pseudo ternary, duobinary, partial response, or the like may be used.

[0192]

As described above, according to the present invention,
The signal peak voltage can be suppressed with a simple device configuration without deteriorating the transmission characteristics and without increasing the size of the device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a multicarrier communication apparatus according to a first embodiment.

FIG. 2 is a diagram showing an example of a partial response class 4 encoding process in a sequential encoding unit according to the first embodiment;

FIG. 3 is a diagram showing a configuration of a receiving portion of the multicarrier communication apparatus according to Embodiment 2.

FIG. 4 is a diagram showing a configuration of a transmission section of a multicarrier communication apparatus according to Embodiment 3.

FIG. 5 is a diagram showing a configuration of a receiving portion of the multicarrier communication apparatus according to Embodiment 3.

FIG. 6 is a diagram showing a configuration of a receiving portion of the multicarrier communication apparatus according to Embodiment 4.

FIG. 7 is a main block diagram showing a detailed configuration of a multi-level maximum likelihood decoding unit of the multicarrier communication apparatus according to Embodiment 4.

FIG. 8 is a diagram showing a configuration of a transmission part of a multicarrier communication apparatus according to Embodiment 5.

FIG. 9 is a diagram showing a configuration of a receiving portion of the multicarrier communication apparatus according to Embodiment 5.

FIG. 10 is a diagram showing a configuration of a receiving portion of the multicarrier communication apparatus according to Embodiment 6.

FIG. 11 is a block diagram showing a configuration of a conventional multicarrier communication device.

[Explanation of symbols]

 Reference Signs List 101 digital modulation section 102 sequential coding processing section 103, 104, 115, 116 delay device 105, 114, 416, 705 adder 106 SP conversion section 107 IFFT section 108 radio transmission section 109 antenna 110 radio reception section 111 FFT section 112, 303, 414, 808 PS conversion unit 113 Successive decoding processing unit 117 Digital demodulation unit 301, 419, 708 Multiplication unit 304 Maximum likelihood decoding unit 311, 605 Data sequence generation unit 312 Encoding unit 313, 607 Addition / subtraction unit 314, 608 Square Units 315, 609 Path selection unit 411 Duplicating unit 412, 507 Despreading unit 413 Code distribution unit 415, 704 Offset addition unit 417, 706 Partial response encoding unit 418, 506, 707, 806 SP conversion unit 420, 509 Synthesis unit 504 , 04 partial response decoding unit 505,805 offset removal unit 508 spread code distribution unit 606 sequentially coding section 604,904 multi-level maximum likelihood decoding section 703 spreading unit 709 adding unit 807 matched filter

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuru Uesugi 3-1, Tsunashimahigashi 4-chome, Kohoku-ku, Yokohama-shi, Kanagawa F-term (reference) 5K022 DD01 DD23 DD33 EE02 EE21 EE31

Claims (15)

[Claims] 1. A sequential coding means for performing a sequential coding including an output amplitude of each of an in-phase component and a quadrature component of a signal to be transmitted including 0 and outputting a coded signal, and performing a serial-parallel conversion on the coded signal. And a first serial-parallel conversion means for outputting the data. 2. The multi-carrier according to claim 1, wherein the successive encoding means sequentially encodes a signal to be transmitted using any one of pseudo ternary, duobinary, and partial response. Communication device. 3. The sequential encoding means delays a signal to be encoded by a predetermined time and subtracts a signal to be encoded with the delayed signal using a partial response encoding system class 4 to sequentially transmit a signal to be transmitted. The multicarrier communication apparatus according to claim 1, wherein encoding is performed. 4. A second serial-to-parallel conversion means for serial-to-parallel conversion of a signal to be transmitted, a spreading means for multiplying the serial-parallel-converted signal by a spreading code, and a second serial-to-parallel conversion to a signal multiplied by the spreading code. 4. A serial-to-parallel conversion means, wherein the sequential coding means sequentially codes the parallel-serial converted signal and outputs a coded signal. A multi-carrier communication device as described. 5. The multicarrier communication apparatus according to claim 4, wherein the spreading means distributes the spreading code to each subcarrier on a chip basis and multiplies the signal of each subcarrier. 6. A second parallel-serial conversion means for performing parallel-to-serial conversion on a coded signal transmitted by performing sequential coding including output amplitudes of 0 for each of the in-phase component and the quadrature component, and performing parallel-serial conversion. A multicarrier communication apparatus, comprising: a sequential decoding unit that performs a sequential decoding, which is an inverse process of the sequential coding, and outputs a decoded signal. 7. The multi-carrier according to claim 6, wherein the successive decoding means decodes a signal which has been subjected to successive coding including an output amplitude of each of the in-phase component and the quadrature component including 0. Communication device. 8. The multicarrier communication apparatus according to claim 6, wherein the successive decoding means adds the coded signal to a signal decoded in the past. 9. The method according to claim 6, wherein the successive decoding means adds a signal encoded by the partial response encoding method class 4 to a signal decoded in the past. A multi-carrier communication device according to claim 1. 10. A maximum likelihood decoding means subtracts a received signal by a replica signal obtained by sequentially encoding a transmitted candidate signal, squares an obtained error signal, and obtains the obtained signal. 8. The multicarrier communication apparatus according to claim 6, wherein a candidate signal having the smallest inter-signal distance information is selected and output. 11. A third serial / parallel converter for serial-to-parallel conversion of a signal output from either the sequential decoder or the maximum likelihood decoder, and a despreader for multiplying the serial / parallel converted signal by a spreading code. 11. The multicarrier communication apparatus according to claim 6, further comprising: means, and third parallel / serial conversion means for performing parallel / serial conversion on the signal multiplied by the spread code. 12. The multicarrier communication apparatus according to claim 11, wherein the despreading means distributes a spreading code to each subcarrier on a chip basis and multiplies the signal of each subcarrier. 13. A base station apparatus comprising the multicarrier communication apparatus according to claim 1. 14. A communication terminal device comprising the multi-carrier communication device according to claim 1. Description: 15. A sequential coding step of performing a sequential coding on a signal to be transmitted, including an output amplitude of each of an in-phase component and a quadrature component including 0, and outputting a coded signal; A first serial-to-parallel conversion step of transmitting the encoded signal, a second parallel-to-serial conversion step of receiving the transmitted encoded signal, and performing parallel-to-serial conversion; A serial decoding step of sequentially decoding a signal which has been subjected to sequential coding including 0 in the sequence and outputting a decoded signal.