JP4938608B2 - Decoding device - Google Patents

Description

  The present invention relates to a decoding device for decoding transmission data.

For example, Patent Document 1 discloses a reception demapping apparatus that can support a plurality of modulation schemes.
JP2002-111754

  The present invention has been made from the above-described background, and an object thereof is to provide a decoding device that more reliably decodes transmission data.

  To achieve the above object, the decoding apparatus according to the present invention decodes the data from a transmission signal modulated by a modulation scheme in which data is assigned to signal points defined on a signal plane representing the phase and amplitude of the signal. The transmission signal includes a plurality of frames each including pattern data of a known pattern, transmission data to be transmitted, and error detection data used for error detection of the transmission data. , A signal point detecting means for detecting each of the signal points from the transmission signal, and an overlapping range detection for detecting an overlapping range of existing ranges on the signal plane of the signal points of the pattern data among the detected signal points And a demodulating means for demodulating the transmission signal, and when the signal point of the transmission data is within the set overlapping range, And a demodulating means for demodulating a plurality of data that can be represented by: when a plurality of data is demodulated from one signal point, an error of the transmission data each including any of these data is demodulated Error detection means for detecting using detection data, and selection means for selecting transmission data in which no error is detected as a result of the error detection.

  Preferably, it further includes an overlapping range storage unit that stores the overlapping range detected by the overlapping range detection unit, wherein the overlapping range detection unit weights the stored overlapping range, and the weighted An overlapping range of a new signal point existing range is detected using the overlapping range.

  Preferably, the overlapping range detecting means limits the overlapping range so as not to exceed a preset maximum value.

  According to the decoding device of the present invention, transmission data can be more reliably decoded.

[Background of the present invention]
In order to help understanding of the present invention, first, the background that led to the present invention will be described.

FIG. 1 is a diagram illustrating an example of signal point arrangement in a QPSK (Quadrature Phase Shift Keying) method.
As shown in FIG. 1, a transmitter for data communication of the QPSK system allocates transmission data on a signal plane representing the phase and amplitude of a signal and transmits data as indicated by P1 to P4 in FIG.
In addition, the receiver determines (demaps) the data transmitted by the transmitter in which region the signal point is defined by the threshold shown in FIG. Determine.
Specifically, the receiver determines that P1 in FIG. 1 is (0, 0), P2 is (0, 1), P3 is (1, 1), and P4 is (1, 0).

FIG. 2 is a diagram illustrating an example of signal point arrangement on the reception side when the S / N (Signal to Noise) of the transmission path is poor.
As shown in FIG. 2, when the S / N of the transmission path is bad, since some signal points have moved beyond the threshold value, the receiver erroneously determines the symbol value of the data.
Therefore, the receiver according to the present invention is improved so as to solve the above-described problem by changing the threshold according to the movement of the signal point and setting the gray zone at the boundary of each region.

[Outline of the Invention]
FIG. 3 shows an example of a gray zone in the QPSK system.
As shown in FIG. 3, for example, when P1 has moved to P1 ′ due to an error, the receiver can correctly determine the symbol value of P1 by changing the threshold value to A.
Here, when P1 moves due to an error, P2, P3, or P4 may also move due to an error.
Therefore, the receiver similarly changes the threshold value to B, C, and D.

When the threshold is changed as described above, for example, the signal point detected in the region a in FIG. 3 can be determined as (0, 0) or (0, 1) by the receiver.
Further, the signal point detected in the region b of FIG. 3 by the receiver can be determined as (0, 0) or (1, 0).
Further, the signal point detected in the region c of FIG. 3 by the receiver can be determined as (1, 0) or (1, 1).
Also, the signal point detected by the receiver in the region d in FIG. 3 can be determined as (0, 1) or (1, 1).
Further, the signal point detected in the area e of FIG. 3 by the receiver can be determined as any of (0, 0), (0, 1), (1, 1), and (1, 0).

As described above, regions a, b, c, d, and e in which one signal point can correspond to a plurality of data are hereinafter referred to as a gray zone.
The receiver according to the present invention calculates a gray zone from known data, demaps transmission data using the gray zone, demodulates the data into a plurality of data, and corrects data using an error detection function such as CRC. Configured to select.
Specifically, the receiver according to the present invention outputs both (0, 0) and (0, 1) determination values for signal points detected in the region a in FIG. The detection function is used to select the correct symbol value, for example (0, 0).
However, for example, the determination value of the signal point detected in the area e in FIG. 3 becomes four values (0, 0), (0, 1), (1, 1), and (1, 0). , The load of error detection function such as CRC increases.

FIG. 4 is another gray zone example in the QPSK system.
As shown in FIG. 4, for example, when P1 has moved due to an error, the receiver
A circle is drawn with the center of P1 and the length of the moving distance (| P1-P1 ′ |) as the radius.
Similarly, the receiver draws a circle centered on P2, P3, and P4 and having a radius of movement distance (| P1-P1 ′ |) radius.
Here, an overlapping area of a plurality of circles is defined as a gray zone.
Specifically, areas a, b, c, and d in FIG. 4 are gray zones.
Comparing the area of the gray zone shown in FIGS. 3 and 4, since the area of the gray zone shown in FIG. 4 is smaller, the load on the error detection function such as CRC is reduced.

As described above, the receiver can set the gray zone as shown in FIG. 3 or FIG. 4, but sets the gray zone according to the moving distance (| P1-P1 ′ |) in which P1 has moved due to an error. Therefore, all areas on the maximum signal plane can be gray zones.
Therefore, the receiver avoids the above-described problem by setting a maximum value in the gray zone.

FIG. 5 is an example of a gray zone maximum value in the QPSK system.
FIG. 6 is another example of the gray zone maximum value in the QPSK system.
As shown in FIG. 5, the receiver sets the gray zone with 3L / 4, which is a distance 3/4 times the inter-code distance L between P1 and P2, as a maximum value.
As shown in FIG. 6, the receiver sets the gray zone with the distance L between the origin and P1 as the maximum value.
Comparing the gray zones shown in FIGS. 5 and 6, in FIG. 5, the determination values of the signal points detected in the region e are (0,0), (0,1), (1,1) and ( 1, 0).
On the other hand, in FIG. 6, since there is no region where the signal point is determined to be quaternary, an effect of reducing the load of an error detection function such as CRC occurs.

Embodiment of the present invention
Hereinafter, embodiments of the present invention will be described.

FIG. 7 is a diagram showing a configuration of the wireless communication system 1 according to the present invention.
FIG. 8 is a diagram showing a configuration of transmission data transmitted by the transmitter 2 shown in FIG.
As shown in FIG. 7, the wireless communication system 1 includes a transmitter 2, a receiver 3, and an antenna 10.
The transmitter 2 modulates the transmission data shown in FIG. 8 via the antenna 10 using a modulation scheme such as QAM or PSK, and transmits the modulated data as a transmission signal.
The receiver 3 receives the transmission signal transmitted from the transmitter 2 via the antenna 10 and decodes transmission data from the transmission signal.

As shown in FIG. 8, the transmission data includes a plurality of frames (frames # 1 to # 3).
Each frame includes a synchronization word of a known pattern (pattern data of a known pattern), transmission data to be transmitted, and an error detection code (error detection data) used for error detection of the transmission data. .

[Hardware configuration]
FIG. 9 is a diagram illustrating a hardware configuration of the receiver 3 illustrated in FIG. 7.
As shown in FIG. 9, the receiver 3 includes an antenna 10, a receiving circuit 30, an A / D converter 32, a DSP (Degital Signal Processor) 34, a DPRAM (Dual Port RAM) 36, a DSP 38, a memory 40 for the DSP 34 (ROM) And a memory 42 (including ROM and RAM) for the DSP 38.

The receiving circuit 30 receives the transmission signal transmitted from the transmitter 2 via the antenna 10.
Further, the receiving circuit 30 amplifies the received transmission signal, converts the frequency into an intermediate frequency (IF) band, and outputs only the IF frequency component to the A / D converter 32.

The A / D converter 32 converts the reception signal input from the reception circuit 30 into a digital reception signal and outputs the received signal to the DSP 34.
The DSP 34 executes a signal processing program stored in the memory 40, demodulates the received signal input from the A / D converter 32, and outputs demodulated data to the DPRAM 36.

The DPRAM 36 stores data input from the DSP 34.
The DSP 38 executes a data processing program stored in the memory 42, acquires data from the DPRAM 36, performs data error detection and data selection.
The DSP 38 outputs the selected data to an output terminal such as an external PC.
That is, the receiver 3 has a hardware component for executing a program by the DSP and decoding data from the received signal.

[Software configuration]
Hereinafter, software executed in the receiver 3 of the wireless communication system 1 will be described.
Note that the functions of the receiver 3 can be realized in terms of software and hardware, but these functions are realized by software (programs) executed by the DSP 34 and the DSP 38 shown in FIG. The case is taken as a specific example.

[Receiver 3]
FIG. 10 is a diagram showing a software configuration of the receiver 3 of the wireless communication system 1 shown in FIG.
As shown in FIG. 10, the receiver 3 includes a quadrature detection unit 300, a signal point detection unit 302, a synchronization unit 304, an equalization unit 50, a gray zone calculation unit 60, and a demapping unit 306, which are mainly executed by the DSP 34. The error detection unit 308 and the data selection unit 310 are mainly executed by the DSP 38.

Each software component of the receiver 3 shown in FIG. 10 is stored in the memory 40 and the memory 42, supplied to the receiver 3, and received on the OS installed in the receiver 3 as necessary. It is executed by specifically utilizing the hardware resources of the machine 3.
The receiver 3 decodes data using these components.

The quadrature detection unit 300 performs quadrature detection on the received signal input from the A / D converter 32 and separates it into I-phase component data and Q-phase component data, and the separated I-phase component data and Q-phase component Is output to the signal point detection unit 302 and the synchronization unit 304.
The synchronization unit 304 generates a synchronization signal from the I-phase component data and the Q-phase component data input from the quadrature detection unit 300, and outputs the generated synchronization signal to the signal point detection unit 302 and the equalization unit 50. To do.

Based on the synchronization signal input from the synchronization unit 304, the signal point detection unit 302 detects the signal point from the I-phase component data and the Q-phase component data input from the quadrature detection unit 300, and the equalization unit 50 is output.
Based on the synchronization signal input from the synchronization unit 304, the equalization unit 50 acquires frame data from the signal point input from the signal point detection unit 302 and detects the synchronization word.
Further, the equalization unit 50 sets an equalization coefficient from the detected synchronization word, and based on the set equalization coefficient, the frame data input from the signal point detection unit 302 and the signal point of the detected synchronization word are determined. to correct.
In addition, the equalization unit 50 outputs the corrected signal point of the frame data to the demapping unit 306.
Further, the equalization unit 50 outputs the corrected signal point of the synchronization word to the gray zone calculation unit 60.

The gray zone calculation unit 60 calculates a gray zone from the signal point of the synchronization word input from the equalization unit 50, and outputs the calculated gray zone to the demapping unit 306.
The demapping unit 306 demaps signal points of the frame data input from the equalization unit 50 based on the gray zone input from the gray zone calculation unit 60, performs symbol determination, and performs one or more frames Demodulate to data.
Further, the demapping unit 306 outputs the demodulated one or more frame data to the error detection unit 308 and the data selection unit 310.

The error detection unit 308 detects an error in one or a plurality of demodulated frame data input from the demapping unit 306 using an error detection code (FIG. 8), and outputs an error detection result to the data selection unit 310. Output.
Based on the error detection result input from the error detection unit 308, the data selection unit 310 selects correct frame data from one or more demodulated frame data input from the demapping unit 306, and selects the selected frame data. Is output to an output terminal such as an external PC.

[Equalization unit 50]
FIG. 11 is a diagram showing a configuration of the equalization unit 50 shown in FIG.
As shown in FIG. 11, the equalization unit 50 includes a frame detection unit 500, a synchronization word separation unit 502, an equalization coefficient determination unit 504, a data correction unit 506, and a synchronization word correction unit 508.
The frame detection unit 500 acquires frame data from the signal point input from the signal point detection unit 302 based on the synchronization signal input from the synchronization unit 304, and the detected frame data is synchronized with the synchronization word separation unit 502 and the data correction. The data is output to the unit 506.

The synchronization word separation unit 502 detects a synchronization word from the frame data input from the frame detection unit 500 based on the synchronization signal input from the synchronization unit 304, and detects the detected synchronization word as an equalization coefficient determination unit 504 and The data is output to the synchronization word correction unit 508.
The equalization coefficient determination unit 504 determines an equalization coefficient based on the synchronization word input from the synchronization word separation unit 502, and outputs the determined equalization coefficient to the data correction unit 506 and the synchronization word correction unit 508. .

The data correction unit 506 corrects the frame data input from the frame detection unit 500 based on the equalization coefficient input from the equalization coefficient determination unit 504, and the corrected frame data is sent to the demapping unit 306. Output.
The synchronization word correction unit 508 corrects the synchronization word input from the synchronization word separation unit 502 based on the equalization coefficient input from the equalization coefficient determination unit 504, and the corrected synchronization word is input to the gray zone calculation unit 60. Output.

[Gray Zone Calculation Unit 60]
FIG. 12 is a diagram showing a configuration of the gray zone calculation unit 60 shown in FIG.
As shown in FIG. 12, the gray zone calculation unit 60 includes a movement detection unit 600, a data holding unit 602, a gray zone setting unit 604, and a gray zone restriction unit 606.

The movement detection unit 600 detects the movement distance of the signal point from the synchronization word input from the synchronization word correction unit 508 of the equalization unit 50, and outputs the detected movement distance to the gray zone setting unit 604.
The data holding unit 602 holds the gray zone input from the gray zone setting unit 604 and outputs the gray zone to the gray zone setting unit 604 when processing subsequent frame data.

The gray zone setting unit 604 sets the gray zone shown in FIG. 4 using the movement distance of the signal point input from the movement detection unit 600 and the gray zone of the previous frame data input from the data holding unit 602. The set gray zone is output to the data holding unit 602 and the gray zone limiting unit 606.
Specifically, the gray zone setting unit 604 sets a gray zone as follows.

For example, a case where the processing target frame is frame # 2 shown in FIG. 8 will be described as a specific example.
As indicated by the arrow with t in FIG. 8, the larger the frame number, the later the process is performed.
It is assumed that the signal point movement distance x2 of the synchronization word in frame # ₂ is input from the movement detection unit 600.
If the gray zone setting distance y ₁ calculated in frame # 1 shown in FIG. 8 is input from the data holding unit 602, the gray zone setting distance z is calculated as z = ax ₂ + by ₁ .
Here, a and b are coefficients for weighting, and satisfy a + b = 1 and a <b.

Further, for example, the case where the processing target frame is the frame # 3 shown in FIG. 8 will be described as a specific example.
From the movement detector 600 and the signal point distance traveled x ₃ of the sync word is input.
Also, assuming that the gray zone setting distance y ₂ calculated in frame # 2 and frame # 1 shown in FIG. 8 is input from the data holding unit 602, the gray zone setting distance z is calculated as z = ax ₃ + by _2. Is done.
Here, a and b are coefficients for weighting, and satisfy a + b = 1 and a <b.

That is, the gray zone setting unit 604 weights the gray zone setting distance in the previous frame data and the signal point movement distance of the synchronization word input from the movement detection unit 600, and adds them to calculate the gray zone setting distance. And set the gray zone.
In the above-described weighting coefficients a and b, by setting a << b, the gray zone does not change abruptly even if the transmission path state deteriorates instantaneously. Is stabilized.
The gray zone limiting unit 606 determines whether or not the gray zone input from the gray zone setting unit 604 exceeds the maximum value. If the gray zone does not exceed the maximum value, the gray zone input unit When it exceeds the value, the maximum value is output to the demapping unit 306.

The processing of the gray zone calculation unit 60 described above will be further described with reference to FIG.
FIG. 13 is a flowchart showing the processing (S10) of the gray zone calculation unit 60.
As shown in FIG. 13, in step 100 (S100), the movement detection unit 600 detects the movement distance of the signal point from the synchronization word input from the synchronization word correction unit 508 of the equalization unit 50, and detects the detected movement. The distance is output to the gray zone setting unit 604.

In step 102 (S102), the gray zone calculation unit 60 determines whether the data holding unit 602 holds a gray zone in the previous frame data.
When the data holding unit 602 holds the gray zone in the previous frame data, the gray zone calculating unit 60 proceeds to the process of S104, and otherwise, proceeds to the process of S106.

In step 104 (S104), the data holding unit 602 outputs the gray zone in the previous frame data to the gray zone setting unit 604.
In step 106 (S106), the gray zone setting unit 604 calculates a gray zone, and outputs the calculated gray zone to the data holding unit 602 and the gray zone restriction unit 606.

In step 108 (S108), the gray zone restriction unit 606 determines whether or not the gray zone input from the gray zone setting unit 604 exceeds the maximum value.
When the gray zone input from the gray zone setting unit 604 exceeds the maximum value, the gray zone calculation unit 60 proceeds to the process of S120, and otherwise proceeds to the process of S110.

In step 110 (S110), the gray zone restriction unit 606 outputs the gray zone input from the gray zone setting unit 604 to the demapping unit 306.
In step 120 (S120), the gray zone restriction unit 606 outputs the maximum value of the gray zone to the demapping unit 306.

Next, the processing of the demapping unit 306 shown in FIG. 10 will be further described with reference to FIG.
FIG. 14 is a flowchart showing the process (S20) of the demapping unit 306.
As shown in FIG. 14, in step 200 (S200), the demapping unit 306 acquires the frame data input from the data correction unit 506 of the equalization unit 50.

In step 202 (S202), the demapping unit 306 acquires the gray zone input from the gray zone calculation unit 60.
In step 204 (S204), the demapping unit 306 determines whether there is a signal point in the gray zone.
When there is a signal point in the gray zone, the demapping unit 306 proceeds to the process of S206, and otherwise proceeds to the process of S210.

In step 206 (S206), the demapping unit 306 performs symbol determination based on the gray zone input from the gray zone calculation unit 60, and a plurality of frames demodulated as described later with reference to FIGS. Data is output to the error detection unit 308 and the data selection unit 310.
Specifically, the frame data is demodulated as follows.

FIG. 15 is a diagram illustrating an example of demodulating frame data, in which (a) illustrates frame data before demodulation, and (b) and (c) illustrate frame data after demodulation.
As shown in FIG. 15, the frame data (a) includes, for example, one signal point detected in the gray zone region a (FIG. 4).
Here, the demapping unit 306 performs symbol determination on the signal points detected in the gray zone region a (FIG. 4) as (0, 0) and (0, 1). b) and (c).

FIG. 16 is a diagram showing an example of demodulation of frame data, where (a) shows frame data before demodulation, and (b), (c), (d), and (e) show frame data after demodulation. Indicates.
As shown in FIG. 16, the frame data (a) includes, for example, signal points detected in the gray zone region a (FIG. 4) and signal points detected in the gray zone region d (FIG. 4) one by one. Including.
Here, the demapping unit 306 performs symbol determination on the signal points detected in the gray zone region a (FIG. 4) as (0, 0) and (0, 1), and performs the gray zone region d (FIG. 4). Since the signal point detected in 4) is subjected to symbol determination as (0, 1) and (1, 1), the demodulated frame data includes four (b), (c), (d) and (e). Become.

  In step 210 (S210; FIG. 14), the demapping unit 306 performs symbol determination based on the gray zone input from the gray zone calculation unit 60, and selects the demodulated single frame data from the error detection unit 308 and the data selection unit. Output to the unit 310.

Next, processing of the error detection unit 308 and the data selection unit 310 illustrated in FIG. 10 will be further described with reference to FIG.
FIG. 17 is a flowchart showing the processing (S30) of the error detection unit 308 and the data selection unit 310.
As shown in FIG. 17, in step 300 (S300), error detection section 308 and data selection section 310 acquire demodulated frame data obtained by the processing of demapping section 306 shown in FIGS.

In step 302 (S302), the error detection unit 308 determines whether or not a plurality of demodulated frame data is input from the demapping unit 306.
When a plurality of demodulated frame data is input from the demapping unit 306, the error detection unit 308 proceeds to the process of S304, and otherwise proceeds to the process of S320.

In step 304 (S304), the error detection unit 308 performs error detection on each demodulated frame data.
In step 306 (S306), error detection section 308 outputs the error detection result of each demodulated frame data to data selection section 310.

In step 308 (S308), the data selection unit 310 determines whether an error has been detected from all the demodulated frame data.
When an error is detected from all demodulated frame data, the data selection unit 310 proceeds to the process of S330, and otherwise proceeds to the process of S310.
In step 310 (S310), the data selection unit 310 selects demodulated frame data for which no error has been detected.

In step 312 (S312), the data selection unit 310 determines whether one demodulated frame data is selected.
When one demodulated frame data is selected, the data selection unit 310 proceeds to the process of S314, and otherwise proceeds to the process of S330.
In step 314 (S314), the data selection unit 310 outputs the selected demodulated frame data to an output terminal such as an external PC.

In step 320 (S320), the error detection unit 308 performs error detection on the demodulated frame data.
In step 322 (S322), the error detection unit 308 outputs the error detection result to the data selection unit 310.
In step 324 (S324), the data selection unit 310 determines whether an error is detected from the demodulated frame data.
When an error is detected from the demodulated frame data, the data selection unit 310 proceeds to the process of S330, and otherwise proceeds to the process of S326.

In step 326 (S326), data selection section 310 selects demodulated frame data for which no error has been detected.
In step 330 (S330), the data selection unit 310 outputs an error message to an output terminal such as an external PC.

[Overall operation]
Next, the processing of the receiver 3 shown in FIG. 10 will be further described with reference to FIG.
FIG. 18 is a flowchart showing the processing (S40) of the receiver 3.
As shown in FIG. 18, in step 400 (S400), the quadrature detection unit 300 performs quadrature detection on the received signal input from the A / D converter 32 to obtain I-phase component data and Q-phase component data. The signal is output to the signal point detection unit 302 and the synchronization unit 304.

In step 402 (S402), the synchronization unit 304 generates a synchronization signal from the I-phase component data and the Q-phase component data input from the quadrature detection unit 300, and the generated synchronization signal is transmitted to the signal point detection unit 302 and the like. To the conversion unit 50.
In step 404 (S404), the signal point detection unit 302 determines the signal point from the I-phase component data and the Q-phase component data input from the quadrature detection unit 300 based on the synchronization signal input from the synchronization unit 304. Detection is performed and output to the equalization unit 50.

In step 406 (S406), the equalization unit 50 acquires frame data from the signal point input from the signal point detection unit 302 based on the synchronization signal input from the synchronization unit 304, detects the synchronization word, and the signal point. Perform the correction.
Further, the equalization unit 50 outputs the corrected signal point of the frame data to the demapping unit 306 and the corrected signal point of the synchronization word to the gray zone calculation unit 60.

In step 408 (S408), the receiver 3 proceeds to the process of S10, and the gray zone calculation unit 60 calculates a gray zone and outputs the calculated gray zone to the demapping unit 306.
In step 410 (S410), the receiver 3 proceeds to the process of S20, the demapping unit 306 performs the demapping process, and the error detection unit 308 and the data selection unit 310 perform the demodulated one or more frame data. Output for.

  In step 412 (S412), the receiver 3 proceeds to the process of S30, and the error detection unit 308 detects an error in the demodulated frame data, outputs the detected error detection result to the data selection unit 310, and the data selection unit 310 performs data selection based on the error detection result input from the error detection unit 308, and outputs the selected data to an output terminal such as an external PC.

19 to 22 are diagrams showing examples of maximum gray zone patterns other than the QPSK (Quadrature Phase Shift Keying) method described above.
FIG. 19 is a diagram showing an example of a maximum gray zone pattern in the 8PSK system, in which (a) shows the maximum gray zone with a certain angle from the threshold as the gray zone, and (b) shows each signal point as the center. The maximum gray zone is shown with the overlapping circles as the gray zone.
In FIG. 19 (a), the maximum gray zone is set between 2/3 of the intersymbol distance (distance from the nearest signal point among adjacent signal points) and the line connecting the origins. Has been.
However, 2/3 of the inter-code distance is merely an example, and may be set to other values such as 3/4 (the same applies to FIGS. 20 to 22 described later).
In FIG. 19B, the radius of the circle is set to 2/3 of the inter-symbol distance, but the radius of the circle defining the maximum gray zone can be set as appropriate (FIGS. 20 to 22 described later). The same applies to).

FIG. 20 is a diagram showing an example of a maximum gray zone pattern in the 16QAM system, where (a) shows the maximum gray zone with a certain distance from the threshold as the gray zone, and (b) shows each signal point as the center. The maximum gray zone is shown with the overlapping circles as the gray zone.
FIG. 21 is a diagram showing an example of a maximum gray zone pattern in the 16QAM (star) system, in which (a) shows a maximum gray zone with a certain distance or angle from the threshold as a gray zone, and (b) The maximum gray zone is shown in which the overlapping of circles around the signal point is the gray zone.
FIG. 22 is a diagram showing an example of a maximum gray zone pattern in the 32QAM system, in which (a) shows a maximum gray zone with a fixed distance or angle from the threshold as a gray zone, and (b) shows each signal point. The maximum gray zone is shown with the overlapping circles at the center as the gray zone.
As described above, the receiver according to the present invention can effectively decode transmission data by performing demapping using a gray zone from a signal transmitted by various modulation schemes.

It is a figure which shows the example of a signal point arrangement | positioning in a QPSK (Quadrature Phase Shift Keying) system. It is a figure which shows the example of a signal point arrangement | positioning at the receiving side in case S / N (Signal to Noise) of a transmission line is bad. It is an example of a gray zone in the QPSK system. It is another example of a gray zone in the QPSK system. It is an example of a gray zone maximum value in the QPSK system. It is another example of the gray zone maximum value in the QPSK system. It is a figure which shows the structure of the radio | wireless communications system 1 concerning this invention. It is a figure which shows the structure of the transmission data which the transmitter 2 shown in FIG. 7 transmits. It is a figure which illustrates the hardware constitutions of the receiver 3 shown in FIG. It is a figure which shows the software structure of the receiver 3 of the radio | wireless communications system 1 shown in FIG. It is a figure which shows the structure of the equalization part 50 shown in FIG. It is a figure which shows the structure of the gray zone calculation part 60 shown in FIG. It is a flowchart which shows the process (S10) of the gray zone calculation part 60. FIG. It is a flowchart which shows the process (S20) of the demapping part. It is a figure which shows the example of demodulation of frame data. It is a figure which shows the example of demodulation of frame data. It is a flowchart which shows the process (S30) of the error detection part 308 and the data selection part 310. FIG. It is a flowchart which shows the process (S40) of the receiver 3. It is a figure which shows the example of the maximum gray zone pattern in 8PSK system. It is a figure which shows the example of the maximum gray zone pattern in 16QAM system. It is a figure which shows the example of the maximum gray zone pattern in 16QAM (star) system. It is a figure which shows the example of the maximum gray zone pattern in 32QAM system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wireless communication system 10 ... Antenna 2 ... Transmitter 3 ... Receiver 30 ... Receiver circuit 300 ... Orthogonal detection part 302 ... Signal point detection part 304 ... Synchronization 306 ... Demapping unit 308 ... Error detection unit 310 ... Data selection unit 32 ... A / D converter 34 ... DSP
36 ... DPRAM
38 ... DSP
40 ... Memory 42 ... Memory 50 ... Equalization unit 500 ... Frame detection unit 502 ... Synchronization word separation unit 504 ... Equalization coefficient determination unit 506 ... Data correction unit 508 ..Synchronized word correction unit 60 ... Gray zone calculation unit 600 ... Movement detection unit 602 ... Data holding unit 604 ... Gray zone setting unit 606 ... Gray zone restriction unit

Claims (3)

A data decoding device that decodes the data from a transmission signal modulated by a modulation method in which data is assigned to signal points defined on a signal plane that represents the phase and amplitude of the signal, the transmission signal being known Including a plurality of frames each including pattern data of the pattern, transmission data to be transmitted, and error detection data used for error detection of the transmission data,
Signal point detecting means for detecting each of the signal points from the transmission signal;
Among the detected signal points, an overlapping range detecting means for detecting an overlapping range of existing ranges on the signal plane of the pattern data signal points;
Demodulating means for demodulating the transmission signal, and when a signal point of the transmission data is in the set overlapping range, demodulating means for demodulating a plurality of data that can be represented by the overlapping range;
Error detection means for detecting an error in the transmission data including any of these data when demodulated from a single signal point using the demodulated error detection data;
And a selection unit that selects transmission data in which no error is detected as a result of the error detection. Further comprising overlapping range storage means for storing the overlapping range detected by the overlapping range detection means,
The decoding apparatus according to claim 1, wherein the overlapping range detection unit weights the stored overlapping range and detects an overlapping range of a new signal point existing range using the weighted overlapping range. The decoding apparatus according to claim 1 or 2, wherein the overlapping range detection means limits the overlapping range so as not to exceed a preset maximum value.

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