JP2003060724A - Multivalued modulating and demodulating device, multivalued modulation and demodulation communication system, modulation and demodulation program thereof and modulating and demodulating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a QAM(quadrature amplitude modulation) system capable of taking a multivalued number of about 2<(p+0.5)> (p is an optional integer). SOLUTION: An input data signal of (2p+1) lines is converted into signals of two (p+1) lines having a prescribed relation to be assigned to two phase planes. A QAM system that can take a multivalued number of about 2<(p+0.5)> is realized by performing time division multiplexing of the two phase planes and performing multivalued modulation of the two phase planes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilevel modulation / demodulation technique, and more particularly to a multilevel modulation / multilevel demodulation device, a multilevel modulation / demodulation communication system, a multilevel modulation / demodulation program, and a multilevel modulation / demodulation program and a multilevel modulation / demodulation program. Value modulation method.

[0002]

2. Description of the Related Art Multilevel modulation technology has been used in the past, especially in digital microwave communication, etc.
AM, 32QAM, 64QAM, 128QAM, 256
A 2 ⁿ QAM method (n is a natural number) such as QAM is often used. Conventionally, these modulation methods have been generally adopted because of the simplicity of the circuit, but in recent years, there has been a strong demand for effective use of frequency and effective use of transmission power. That is, it is required to secure the required data transmission capacity without waste while keeping the frequency band secured as a digital microwave communication line as narrow as possible. This is because, for example, since the required data transmission capacity cannot be realized by the 16QAM method, the 32QAM method is adopted, but the 32QAM method has a large margin of the data transmission capacity and wastefully occupies the frequency band. It is a request to improve the situation such as.

To meet such a demand, for example, there is a technique disclosed in "Multilevel modulation / demodulation communication method and system thereof" in JP-A-04-196945. According to this, a general configuration has been proposed in which one input data is assigned to two or more modulation symbols.

[0004]

However, this prior example only shows a general configuration, and does not disclose a specific configuration method for assigning an input signal sequence to a plurality of modulation symbols. Therefore, for example, a multi-valued number is 2
^{When it} is desired to take about ^{(p + 0.5)} (p is an arbitrary positive integer), it is not shown how it can be realized, and a method for freely setting a multivalued number is realized. Had difficulty.

A first object of the present invention is to provide a multilevel modulation / demodulation device, a multilevel modulation / demodulation communication system, a modulation / demodulation program therefor, and a modulation / demodulation method which can solve the above-mentioned drawbacks of the prior art and more flexibly set a modulation frequency. Is to provide.

A second object of the present invention is to solve the above-mentioned drawbacks of the prior art, to effectively use the frequency and to reduce the required signal-to-noise ratio to 2 ^(n-0.5) Q as compared with the 2 ⁿ QAM system.
To provide a multilevel modulation / demodulation device and a multilevel modulation / demodulation communication system capable of implementing AM, a modulation / demodulation program therefor, and a modulation / demodulation method.

[0007]

A multilevel modulator according to the present invention converts an input data signal of 2p + 1 columns into two signals of p + 1 columns and assigns each to a phase plane, and the two phase planes are combined. They are time-division-multiplexed as a set, multi-value modulated, and transmitted. At this time, by assigning a predetermined relationship to the allocation of the coordinates on the two phase planes forming a set, a configuration in which p + 0.5 bits are allocated to one modulation symbol is realized.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the present invention, p is an arbitrary positive integer,
In a multilevel modulation scheme in which an input signal of 2p + 1 columns is assigned to two modulation symbols, (3/2) × 2 ^p signal points are used in the first modulation symbol and the first modulation symbol is used in the second modulation symbol. Of (3/2) × 2 ^p signal points for 2 ^p signal points of the modulation symbols of
It is characterized in that 2 ^p signal points are used for the remaining 2 ^(p−1) signal points of the modulation symbol of ¹ . The modulation method of the present invention is based on the following expression when p is an arbitrary integer.

2 ^{(2p + 1)} = (3/2) × 2 ^p × 2 ^p +2 ^p × 2 ^(p−1) Equation (1) The first term on the right side of this Equation (1) is (3/2) × 2 ^p QAM
By 2 ^p times and 2 ^p QAM 2 ^(p−1) times, the total number becomes equal to 2 ^{(2p + 1)} times. That is, for one modulation symbol, p +
Perform the operation to which 0.5 bits are allocated. From this, according to the present invention, it is possible to set the multilevel number to 2 ^{(n + 0.5)} in the QAM system.

FIG. 1 is a block diagram showing the configuration of a multilevel modulation apparatus 100 according to the first embodiment of the present invention. Referring to FIG. 1, a multilevel modulation device 100 according to the present embodiment.
Includes an input terminal 1, a first data conversion circuit 2, a second data conversion circuit 3, a parallel / serial conversion circuit 4, a multilevel modulator 5, and an output terminal 6.

The first data conversion circuit 2 and the second data conversion circuit 3 convert the input data signal 10 input to the input terminal 1. The first data conversion circuit 2 has p + indicating a value of (3/2) × 2 ^p types according to the value of the input signal 10.
The signal 21 of one column is output. Second data conversion circuit 3
Outputs the signal 31 in the p + 1 column according to the value of the input data signal 10 input to the input terminal 1. Here, when the first data conversion circuit outputs the predetermined 2 ^p types of values (these are referred to as a set A), the predetermined (3/2) × 2 ^p types are correspondingly output. Is output, and the first data conversion circuit outputs 2 ^(p-1) kinds of values other than the set A (these are referred to as a set B), a predetermined 2 ^p
Output the seed value.

The parallel-serial conversion circuit 4 includes the above-mentioned signals 21,
31 is input, time division multiplexing is performed, and a multiplexed signal 41 of the p + 1 column is output. The multi-level modulator 5 multi-level modulates the multiplexed signal 41 and outputs it to the output terminal 6.

FIG. 2 is a block diagram showing the configuration of a multilevel demodulator 200 according to the first embodiment of the present invention. Referring to FIG. 2, a multilevel demodulator 200 according to the present embodiment.
Includes an input terminal 11, a multilevel demodulator 12, a serial-parallel conversion circuit 13, a data inverse conversion circuit 14, and an output terminal 15.

The multi-level demodulator 12 demodulates the communication signal 111 input to the input terminal 11 and outputs a reception demodulated data sequence signal 121 of p + 1 sequence. The serial-parallel conversion circuit 13 has
The received demodulated data sequence signal 121 is time-division demultiplexed and demultiplexed, and the first demodulated data sequence signal 131 and the second demodulated data sequence signal 132 of p + 1 columns are output. The data inverse conversion circuit 14 includes a first demodulated data string signal 131 and a second demodulated data string signal 131.
And the demodulated data string signal 132 of 1 are input and the demodulated data signal 141 of 2p + 1 columns is output. Here, the data inverse conversion circuit 14 outputs (3 /
2) When a signal indicating 2 × 2 ^p types of values is received and the first demodulation data sequence signal 131 is a predetermined 2 ^p types of values (set A) as the second demodulation data sequence signal 132, Corresponding to this, a signal indicating a predetermined (3/2) × 2 ^p type value is received, and the first demodulated data sequence signal 131 receives 2 ^(p−1) type values (set ⁾ other than the set A. In the case of B), in response to this, a signal indicating a predetermined 2 ^p type value is received,
A predetermined demodulation data value is generated based on the value indicated by the first demodulated data string signal 131 and the value indicated by the second data string signal 132, and this is output as the demodulated data signal of 2p + 1 columns.

Next, the multilevel modulation device 100 of the present embodiment
The operation of the multilevel demodulator 200 will be described with reference to the drawings.

FIG. 3 is a block diagram of the multilevel modulation device 10 of this embodiment.
6 is a timing chart showing signal conversion inside each unit of 0. (1) of FIG. 3 shows the input data signal 10 of FIG. The horizontal axis of FIG. 3 is a time axis, and shows that the input data signal 10 changes at regular time intervals. 3 (2A) and (2B) show the signal 21 output from the first data conversion circuit 2 and the signal 31 output from the second data conversion circuit 3 in FIG. 1, respectively. (3) of FIG. 3 shows the multiplexed signal 41 output from the parallel-serial conversion circuit 4 of FIG. In FIG. 3 (3), (2A) and (2
The signal of (B) is time-division-multiplexed, and the signal of (2A) is output in the A period of (3) and the signal of (2B) is output in the B period of (3).

FIG. 4 shows the correspondence between the value of the input signal (binary signal) 10 in the 2p + 1 column and the value of the signal output to the output terminal 6 for p = 4 as an example. Referring to FIG. 4, 9 columns of input signals (9-bit configuration) from p = 4
I am trying.

Of the two modulation symbols, the first modulation symbol takes values from 1 to 24. Then, when the value of the first modulation symbol takes a value from 1 to 16,
The second modulation symbol has a value from 1 to 24,
When the modulation symbol of 1 has a value of 17 to 24, the second modulation symbol has a value of 1 to 16.

At this time, the types of signals that can be represented by two modulation symbols are 16 × 24 + 8 × 16 = 512.
Becomes Here, 16 in the first term, 16 × 24, indicates that the first modulation symbol takes a value from 1 to 16, and 24 is a value from the first symbol, from 1 to 16 respectively. , The second modulation symbol has a value from 1 to 24. Also, the second term 8 × 16
8 indicates that the first modulation symbol takes values from 17 to 24, and 16 indicates that the second modulation symbol is 1 for each of 17 to 24 of the first modulation symbol. It shows that it takes the value from 16 to 16. In this way, the correspondence between the input signal and the first and second modulation symbols can be uniquely determined, so the first and second data conversion circuits are ROM (Read Only Memory).
This can be easily realized by adopting a configuration such as storing a predetermined data table in a device or the like. It is needless to say that the present invention is valid for any positive integer p, and the present invention is not limited to the case of p = 4 with reference to FIG.

FIG. 5 is a signal diagram in which the first and second modulation symbols of the modulation signal output from the multilevel modulator 5 are expressed as a so-called constellation on the phase plane. Figure 5
Then, A1, B1 and A384, B384 indicate possible coordinates of the first symbol and the second symbol when the value of the input signal is between 1 and 384. That is, A1 indicates possible coordinates of the first symbol when the input signal value is 1, B1 indicates possible coordinates of the second symbol when the input signal value is 1, and A384 indicates an input signal value of 384. Coordinate of the first symbol in the case of, B38
4 shows possible coordinates of the second symbol when the value of the input signal is 384, and shows that both of the first and second symbols can take 24 coordinates in this value range (where the first The symbols are limited to 16 specific coordinates out of 24). The value of the input signal is 385 to 51.
In the range up to 2, the first symbol takes 8 coordinates out of the 24 coordinates that are not taken when the input value is 384 or less, and the second symbol takes only 16 coordinates. Indicates that there is no.

[Other Embodiments of the Present Invention] Since the present invention shows a construction method in a general form that can be implemented with an arbitrary positive integer p, for example, 6QAM, 12QA
It can be applied to many systems such as M, 24QAM, 48QAM and 96QAM.

FIG. 6 shows a concrete example in the case of configuring such another QAM system. FIG. 6 shows the multi-valued numbers of the first and second modulation symbols and the number of repetitions thereof. For example, if you want to communicate at a transmission rate of 150 [Mbps] but the frequency band is 35 [Msymbol / se
If there is only about c], it is 30.0 in 32QAM.
[Msymbol / sec] results in a large margin of bandwidth, but in 16QAM, 37.5 [Msymbo]
1 / sec], the bandwidth is insufficient. In such a case, if the 24QAM shown in FIG.
Since the modulation rate of 3.3 [Msymbol / sec] can be secured, it becomes possible to transmit the band efficiently.

As yet another embodiment, the multilevel modulation / demodulation apparatus of the present invention is provided with a control means, and a data conversion table for multilevel modulation and multilevel demodulation is stored in a RAM (R).
The data conversion table can be configured to be changeable by the control means, which is configured by an and access memory device, etc., and is stored in the RAM. By thus changing the data conversion tables of the modulator and the demodulator so as to correspond to each other, the relationship between the value of data to be transmitted and received and the code (coordinates on the constellation) of the communication signal can be arbitrarily changed. The confidentiality of transmitted / received data can be improved.

The multilevel modulation apparatus 300 shown in FIG. 7 is obtained by adding multilevel modulation control means 7 to the multilevel modulation apparatus 100 shown in FIG. Since the other parts are common to those in FIG. 1, the same reference numerals as those in FIG. The multilevel modulation control means 7 in FIG.
The first data conversion circuit 2 and the second data conversion circuit 3 are controlled to change the data conversion table.

The multilevel demodulator 400 of FIG. 8 is obtained by adding the multilevel demodulation control means 16 to the multilevel demodulator 200 of FIG. The other parts are common to those in FIG. 2, and are therefore given common reference numerals. Multilevel demodulation control means 16 of FIG.
Controls the data reverse conversion circuit 14 and changes the data reverse conversion table.

Further, the first data conversion circuit 2 and the second data conversion circuit 3 in FIG. 7 are constituted by the input / output devices of the multilevel modulation control means 7, and the data of the first and second data conversion circuits are formed. The conversion function may be configured to be performed by a computer included in the multilevel modulation control means 7. In this case, the data conversion processing is performed by the control program of the multilevel modulation control means 7.

FIG. 9 is a flow chart of a program to be executed by the computer of the multilevel modulation control means 7 in the case of such a configuration. The multi-level modulation control means 7 is S1
Input the input data signal with. Subsequently, in S2, first conversion data corresponding to the value of the input data signal is generated, and S
In step 3, the second converted data is generated. These conversion data can be easily generated by referring to the conversion table shown in FIG. 4, for example. In S4, the first and second conversion data are sequentially output to the parallel / serial conversion circuit 4. FIG. 9 shows a process of converting one input data. Needless to say, it is possible to control the sequential modulation signals to be transmitted by repeatedly executing the processing shown in this flowchart as the input data signals are sequentially supplied as shown in the timing chart of FIG.

Similarly, the data inverse conversion circuit 14 of FIG.
Is composed of an input / output device of the multilevel demodulation control means 16,
The data inverse conversion function of the data inverse conversion circuit may be configured to be performed by the computer included in the multi-level demodulation control means 16. In this case, the control program of the multi-level demodulation control means 16 is configured to perform the data inverse conversion process.

FIG. 10 is a flow chart of a program to be executed by the computer of the multilevel demodulation control means 16 in the case of such a configuration. Multilevel demodulation control means 16
Inputs the first demodulated data in S11 and the second demodulated data in S12. Subsequently, in S13, demodulated data values corresponding to the first and second demodulated data are generated. The inverse conversion data can be easily generated by, for example, creating an inverse conversion table of the conversion table shown in FIG. 4 and referring to it. In S14, the demodulated data value is output as the demodulated data signal of the 2p + 1 column. FIG. 10 shows a process of inputting and converting a set of demodulation data. It goes without saying that it is possible to control to sequentially output the demodulated data signal by repeatedly executing the processing shown in this flowchart as the demodulated data is sequentially supplied.

[0031]

As described above, according to the present invention, 2p +
After allocating 1 column of input data to 2 modulation symbols and then multiplexing the 2 modulation symbols on the time axis, a binary data sequence of p + 0.5 columns is transmitted by 1 system of modulation symbol sequence. Therefore, it is possible to set the multilevel number of the QAM method to about 2 ^{(p + 0.5)} . As a result, in the case where 2 ⁿ QAM has too much room in the frequency band but 2 ^(n-1) QAM exceeds the required frequency band, it is possible to provide an intermediate modulation method. As a result, not only the frequency can be used more effectively, but also 2 ^(n-0.5) QAM can be realized with a required signal-to-noise ratio smaller than that of 2 ⁿ QAM, and the effective use of power can be achieved. can get.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a multilevel modulation apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a multilevel demodulator according to the first embodiment of the present invention.

FIG. 3 is a timing chart showing signal conversion of each unit of the multilevel modulation apparatus according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a configuration example of a data conversion table of first and second data conversion circuits of the multilevel modulation apparatus according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing coordinates that can be taken on a constellation in the multilevel modulation signal according to the first embodiment of the present invention.

FIG. 6 is a QA when configuring another embodiment of the present invention.
It is a figure which shows the specific example of the parameter which comprises a M modulation system.

FIG. 7 is a block diagram showing a configuration of a multilevel modulation apparatus according to another embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a multilevel demodulator according to another embodiment of the present invention.

FIG. 9 is a flowchart of an example of a program to be executed by a computer included in a multilevel modulation control unit of a multilevel modulation apparatus according to another embodiment of the present invention.

FIG. 10 is a flowchart of an example of a program to be executed by a computer included in the multilevel demodulation control means of the multilevel demodulator according to another embodiment of the present invention.

[Explanation of symbols]

100 Multi-level modulator 1 input terminal 2 First data conversion circuit 3 Second data conversion circuit 4 parallel-serial conversion circuit 5 Multi-level modulator 6 output terminals 7 Multilevel modulation control means 11 input terminals 12 Multilevel demodulator 13 Series-parallel conversion circuit 14 Data inverse conversion circuit 16 Multilevel demodulation control means

Claims (9)

[Claims] 1. Input of 2p + 1 columns (p is an arbitrary positive integer)
Multi-level modulation for multi-level modulation of force data signal and output of communication signal
In the device, First and second input and conversion of the input data signal
A data conversion circuit and the first and second data conversion circuits
Parallel-serial conversion circuit that time-division-multiplexes the output signal of the path, and
The output signal of the parallel-to-serial conversion circuit is multi-valued modulated and the communication signal is converted.
And a multi-value modulator for outputting, the first data conversion circuit
The path is (3/2) × 2 depending on the value of the input data signal. ^p
A second data conversion circuit for outputting a signal indicating a seed value
Is the first data conversion based on the input data signal
The circuit has predetermined 2^pSeed value (hereinafter, this 2^pSeed value
If a signal indicating “Set A” is output,
Specified (3/2) x 2^pOutputs a signal indicating the seed value,
If the first data conversion circuit is not included in the set A,
^(P-1)Seed value (hereinafter, this 2^(P-1)Seed value
If a signal indicating “Set B” is output,
Specified 2^pConfigured to output a signal indicating the seed value
A multilevel modulation device characterized in that 2. A communication signal is demodulated and 2p + 1 columns (p is an arbitrary number)
A multi-valued demodulation device that outputs a demodulated data signal of any positive integer
In the Demodulates the communication signal and outputs a received demodulated data string signal
And a multi-valued demodulator for
Separate the first demodulated data sequence signal and the second demodulated data sequence signal.
And a serial-to-parallel conversion circuit that outputs
Data sequence signal and the second data sequence signal are input, and 2p +
Data inversion circuit for outputting the demodulated data signal in one column
And the data inverse conversion circuit includes:
(3/2) x 2 as data string signal ^pA signal indicating the seed value
And receives the first demodulated data string signal as the first demodulated data string signal.
The demodulated data string signal has a predetermined value of 2^pSeed value (hereinafter, this
Two^pIf the seed value is "Set A"), the
Metta (3/2) x 2^pUpon receiving a signal indicating the seed value,
The demodulated data string signal of 1 is 2 other than that of the set A.^(P-1)
Seed value (hereinafter, this 2^(P-1)Seed value as "set B"
2) is set in advance if^pA signal that indicates the seed value
In response to the value indicated by the first demodulated data string signal and the
2p predetermined based on the value indicated by the second data string signal
It is configured to output the demodulated data signal of +1 column.
A multi-valued demodulator featuring. 3. A multilevel modulation / demodulation communication system, comprising the multilevel modulation apparatus according to claim 1 and the multilevel demodulation apparatus according to claim 2. 4. The multi-level modulation apparatus according to claim 1, further comprising multi-level modulation control means for controlling the first and second data conversion circuits, wherein the multi-level modulation control means comprises: A multilevel modulation device characterized in that the correspondence between the input data signal and the output value of the first and second data conversion circuits can be changed. 5. The multilevel demodulator according to claim 2, further comprising multilevel demodulation control means for controlling the data inverse conversion circuit, wherein the multilevel demodulation control means is an input of the data inverse conversion circuit. A multilevel modulation device, wherein correspondence between the first demodulated data sequence signal and the second demodulated data sequence signal and the output value can be changed. 6. A multilevel modulation / demodulation communication system comprising the multilevel modulation apparatus according to claim 4 and the multilevel demodulation apparatus according to claim 5. 7. By controlling a computer, 2
Many input data signals in the p + 1 column (p is an arbitrary positive integer)
In a multi-value modulation program that performs value modulation, the input data
Data signal into the first and second conversion data.
And execute the input data as the first conversion data.
(3/2) x 2 depending on the value of the signal ^pSeed value, before
As the second conversion data, it corresponds to the value of the input data signal.
Then, the first conversion data has a predetermined value of 2^pSeed value
(Hereafter, this 2^pWhen taking the value of the seed as "Set A")
In the case of (3/2) × 2^pSeed value, before
Note that the first conversion data is a predetermined 2 other than the set A.
^(P-1)Seed value (hereinafter, this 2^{(P-1 )}Seed value
If set to “Set B”, the predetermined 2^pSeed
A value is taken and the first conversion data and the second conversion data are
Data is sequentially output to the multilevel modulator.
Multilevel modulation program. 8. A communication signal is multi-valued demodulated by controlling a computer, and 2p + 1 columns (p is an arbitrary positive integer)
In the multilevel demodulation program for outputting the demodulated data signal of, the process of inputting the communication signal as the first and second demodulated data sequence signals and converting it into the demodulated data signal of the 2p + 1 sequence is performed. As the demodulated data sequence signal, a signal indicating a value of (3/2) × 2 ^p types is received, and as the second demodulated data sequence signal, the first demodulated data sequence signal has a predetermined value of 2 ^p types ( Hereinafter, when the value of this 2 ^p type is referred to as “set A”), a predetermined value (3/2) ×
When the first demodulated data string signal receives a signal indicating 2 ^p kinds of values, the 2 ^(p-1) kinds of values other than the set A (hereinafter, the 2 ^(p-1) kinds of values are referred to as “a set”. B)), a signal having a predetermined value of 2 ^p types is received, and based on the value shown by the first demodulated data string signal and the value shown by the second data string signal. Take a predetermined demodulation data value,
A multilevel demodulation program, wherein the demodulated data value is output as a demodulated data signal of 2p + 1 columns. 9. In a multilevel modulation / demodulation method in which an input signal of 2p + 1 columns (p is an arbitrary positive integer) is assigned to two modulation symbols, the first modulation symbol is (3/2) × 2 ^p signal points. When the first modulation symbol takes 2 ^p signal points that are predetermined (hereinafter, the 2 ^p points are referred to as “set A”), the second modulation symbol is Taking (3/2) × 2 ^p signal points defined corresponding to the input signal, the first
Modulation symbols of 2 ^(p-1) points other than the set A (hereinafter, the 2 ^(p-1) points are referred to as "set B")
2 ^p determined in advance corresponding to the input signal
A multilevel modulation method characterized by taking individual points.