JP2001102971A - Method and system for transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a system for transmission which can reduce errors of transmit data even in a propagation system where deterioration in S/N or a momentary break occurs periodically or intermittently. SOLUTION: On a transmission side, two successive pieces of data for learning are added to transmission data and they are modulated and transmitted. On a reception side, an equalizing process is performed by using learning circuits 5a and 5b and equalizing circuits 6a and 6b provided as to those two pieces of data for learning and data having a small error is employed by a selecting circuit 7 and demodulated by a demodulating circuit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission method on a propagation path in which S / N degradation or instantaneous interruption occurs periodically or intermittently, and more particularly to a transmission method and a transmission system capable of reducing transmission data errors. .

[0002]

2. Description of the Related Art A modulation method in a conventional transmission method will be described with reference to FIGS. FIG. 5 is a functional block diagram of a conventional modulation unit, and FIG. 6 is an explanatory diagram showing conventional transmission frame generation. As shown in FIG. 5, a conventional modulation unit receives a transmission data, and adds a learning data (PN pattern) to a frame generation circuit 1 ', and converts the generated frame into an arbitrary system (for example, 16QAM system). , And a modulation circuit 2 for outputting transmission data.

In FIG. 6, transmission data is continuously input as an input of a frame generation circuit 1 ', and learning data is inserted and output as an output of the frame generation circuit 1' before the transmission data.

[0004] A demodulation unit in a conventional transmission method will be described with reference to FIG. FIG. 7 is a functional block diagram of a conventional demodulation unit. As shown in FIG. 7, a conventional demodulation unit receives a modulated wave and performs detection, a detection circuit 3 that establishes synchronization, and a synchronization circuit 4 that outputs a frame synchronization signal. A learning circuit 5 that outputs the equalization parameter obtained by predicting the inverse characteristic of the propagation path by bringing the learning data in the detected detection signal closer to the learning data that would have been transmitted; It comprises an equalizing circuit 6 for correcting a phase of a signal using an equalization parameter, and a demodulating circuit 8 for demodulating a phase-corrected detection signal and outputting received data.

[0005] As shown in FIG. 8, as a propagation state in which the S / N deteriorates or intermittently or periodically occurs intermittently,
There is a case where rotor modulation occurs due to interference between a rotor blade of a helicopter and a transmitting / receiving antenna attached to the helicopter. FIG. 8 is an explanatory diagram illustrating a case where rotor modulation occurs.

When the rotor modulation occurs, as shown in FIG. 9 (b), the S / N deteriorates at a constant period. If the S / N ratio of the frame including the transmission data illustrated in FIG. 9A is deteriorated, an error occurs in the reception data as illustrated in FIG. 9C. When the deterioration of S / N overlaps with the portion of the learning data in the transmission frame, the anti-phase characteristic of the propagation path is incorrectly calculated. This means that a data error has occurred and one frame of data has been lost due to learning failure. FIG. 9 is an explanatory diagram showing a conventional reception result output example.

The transmission path equalization processing is disclosed in Japanese Patent Laid-Open Publication No. Hei 5-5595 published March 5, 1993.
No. 6, "Adaptive equalizer" (applicant: Fujitsu Limited, inventor: Takashi Kimoto et al.). The present invention adaptively equalizes not only linear distortion but also non-linear distortion by detecting characteristics of a transmission path and performing equalization using the result. Is accumulated and trained by a neural network to adapt to the actual environment.

[0008]

As described above, according to the conventional transmission method described above, in a propagation system in which the S / N is degraded or instantaneously interrupted periodically or intermittently, the transmission state of the learning data portion is poor. However, there is a problem that the entire data for one frame is erroneous.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a transmission method and a transmission system capable of reducing errors in transmission data even in a propagation system in which S / N degradation or instantaneous interruption occurs periodically or intermittently. The purpose is to provide.

[0010]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems of the prior art is a transmission method, comprising:
A plurality of different types of learning data are added to transmission data to generate and modulate a frame, and the demodulation side detects a modulated signal and transmits the detected signal using a plurality of types of learning data. Performing an equalization process for estimating a path, selecting an estimated detection signal having a small error in each equalization process, and demodulating the selected detection signal,
Even if there is an error in certain learning data, a detection signal that has been equalized using the learning data containing no error is selected and demodulated, so that errors in transmission data can be reduced.

Further, the present invention provides a transmission system comprising:
A modulating unit that includes a frame generating unit that generates a frame by adding a plurality of types of learning data to transmission data; and a modulating unit that modulates the generated frame, and wherein the demodulating unit detects a modulated wave. Detecting means, synchronizing means for establishing synchronization and outputting a frame synchronization signal, provided in accordance with a plurality of types of learning data, and converting corresponding learning data of the detection signal into original learning data in accordance with the frame synchronization signal. Learning means for outputting an equalization parameter for approximation, and an equalization means provided corresponding to the learning means, for performing an equalization process of phase correction by an equalization parameter input from the corresponding learning means for the detected signal, A detection unit that receives the phase-corrected detection signal output from each equalization unit and selects a signal having few errors; and a demodulation unit that demodulates the signal selected by the selection unit. Cage, even if there is an error in a certain learning data, demodulated by selecting a detection signal equalization processing using the learning data including no error can be reduced errors in transmitted data.

[0012]

Embodiments of the present invention will be described with reference to the drawings. Note that the function realizing means described below may be any circuit or device as long as the function can be realized, and some or all of the functions may be realized by software. is there. Further, the function realizing means may be realized by a plurality of circuits, or the plurality of function realizing means may be realized by a single circuit.

In the transmission method according to the embodiment of the present invention, when a modulation side adds learning data to transmission data to generate a frame and modulates the transmission data, a plurality of different learning data types are used for the transmission data. In order to add data, the demodulation side detects the modulated signal, and performs an equalization process on the detected signal to estimate a transmission path using the plurality of learning data,
In each equalization process, an estimated detection signal having few errors is selected, and the selected detection signal is demodulated.

Thus, the demodulation side can perform the equalization process using a plurality of types of learning data. Therefore, even if the learning data has an error, the equalization is performed using the learning data containing no error. The processed detection signal can be selected and demodulated, and errors in transmission data can be reduced.

Further, in the transmission system according to the embodiment of the present invention, as a modulator, a frame generating means for generating a frame by adding a plurality of types of learning data to transmission data; A modulating means for modulating, as a demodulation unit, a detecting means for detecting a modulated wave, a synchronizing means for establishing synchronization and outputting a frame synchronizing signal,
A learning unit that is provided in accordance with a plurality of types of learning data and outputs an equalization parameter for bringing the corresponding learning data of the detection signal closer to the original learning data in accordance with the frame synchronization signal; Provided, an equalizing means for performing phase correction with an equalization parameter input from a learning means corresponding to the detected signal, and a phase-corrected detection signal output from each equalizing means, and a signal having few errors is input. There is provided a selecting means for selecting and a demodulating means for demodulating the signal selected by the selecting means.

Thus, the demodulation unit can perform an equalization process for correcting the phase of the detection signal using a plurality of types of learning data, so that even if there is an error in certain learning data, the error is not included. It is possible to select and demodulate a detection signal that has been equalized using the learning data, thereby reducing errors in transmission data.

In the modulation section, the frame generating means corresponds to the frame generating circuit 1 of FIG. 1, and the modulating means corresponds to the modulating circuit 2 of FIG. In the demodulation section, the detection means is provided in the detection circuit 3 of FIG. 3, and the synchronization means is provided in the synchronization circuit 4 of FIG.
The plurality of learning means are provided in the learning circuits 5a and 5b of FIG. 3, the plurality of equalization means are provided in the equalization circuits 6a and 6b of FIG. 3, the selection means is provided in the selection circuit 7 of FIG. Corresponding to the demodulation circuit 8.

Next, a modulator of the transmission system according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a functional block diagram of a modulation unit according to the embodiment of the present invention.
Parts having the same configuration as in FIG. 5 are described with the same reference numerals. As shown in FIG. 1, the modulation unit according to the present embodiment receives a transmission data, and adds two consecutive learning data (PN patterns) to the frame generation circuit 1 and converts the generated frame into an arbitrary format ( For example, the modulation circuit 2 performs modulation by the 16QAM method and outputs transmission data.

The frame generation in the frame generation circuit 1 will be described with reference to FIG. FIG. 2 is an explanatory diagram showing transmission frame generation according to the embodiment of the present invention. As shown in FIG. 2, the input of the frame generation circuit 1 has transmission data continuous, and the output of the frame generation circuit 1 has two types of learning data inserted between the transmission data. , Two types of learning data (1) and (2) are inserted before the learning data.

A demodulation section according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a functional block diagram of the demodulation unit according to the embodiment of the present invention. The demodulation unit according to the embodiment of the present invention includes, as shown in FIG.
Synchronizing circuit 4, learning circuits 5a and 5b, and equalizing circuits 6a and
6b, a selection circuit 7, and a demodulation circuit 8.

Each part of the demodulation section according to the embodiment of the present invention will be specifically described. The detection circuit 3 receives the modulated wave, performs detection, and outputs the detection signal to the learning circuits 5a and 5b and the equalization circuit 6
a and 6b. The synchronization circuit 4 establishes synchronization and outputs a frame synchronization signal to the learning circuits 5a and 5b.

The learning circuit 5a makes the learning data (1) in the detected signal closer to the learning data (1) that would have been transmitted originally, thereby predicting the inverse characteristic of the propagation path, thereby obtaining an equalization parameter. Is output to the equalization circuit 6a.
The learning circuit 5b performs learning data (2) in the detected signal.
Is approximated to the learning data (2) that would have been transmitted, and the equalization parameter obtained by predicting the inverse characteristic of the propagation path is output to the equalization circuit 6b.

The equalization circuit 6a corrects the phase of the input detection signal using the equalization parameter input from the learning circuit 5a, and outputs it to the selection circuit 7. The equalization circuit 6b
The input detection signal is subjected to phase correction using the equalization parameter input from the learning circuit 5b, and is output to the selection circuit 7.

The selection circuit 7 includes an equalization circuit 6a and an equalization circuit 6
Each detection signal whose phase has been corrected in b is input, and a detection signal having few errors is selected and output to the demodulation circuit 8. The demodulation circuit 8 demodulates the detection signal selected by the selection circuit 7 and outputs received data.

As described above, in the demodulation unit according to the embodiment of the present invention, the detection signal is phase-corrected by using a plurality of types of learning data, and a detection signal having few errors among the phase-corrected detection signals. Select and demodulate it. In other words, even if an error occurs in a part of the learning data portion, the phase of the detection signal is corrected using the learning data in which no error has occurred, and the error-free detection signal is demodulated. Data errors can be reduced.

Next, the reception result output when the transmission method and the transmission system according to the embodiment of the present invention are used will be described with reference to FIG. FIG. 4 is an explanatory diagram showing a reception result output example according to the embodiment of the present invention. FIG. 4 shows data on a propagation path in which S / N degradation or instantaneous interruption occurs periodically or intermittently. When the transmission data of FIG. 4A undergoes periodic S / N deterioration due to the rotor modulation of FIG. 4B, FIG.
As shown in (1), in the learning data (1) system, when the learning data portion and the S / N degraded portion overlap, the antiphase characteristic of the propagation path is erroneously calculated, and one frame worth of data is obtained. (Data loss for one frame due to learning failure).

However, as shown in FIG. 4D, in the system of the learning data (2), since the anti-phase characteristic of the propagation path can be correctly calculated, data loss of one frame does not occur. Therefore, the learning data (1) and the learning data (2)
If either one of the two signals can be received, data loss for one frame does not occur, and a demodulation result as shown in FIG. 4E can be obtained by selective combining of both systems.

As described above, by outputting the received data of the system with few errors in the learning circuit, the S / S is periodically or intermittently output.
There is an effect that it is possible to prevent the reception data of one frame from being lost due to the propagation system in which the deterioration of N or the instantaneous interruption occurs.

A specific example of a propagation system in which the S / N is deteriorated or intermittently or intermittently or intermittently described is that the helicopter may be subjected to rotor modulation by a rotor blade. Considering the communication between helicopters and helicopters, if there is an altitude difference between the helicopters, the aerial is blocked by the rotor blades, so that periodic deterioration in S / N is observed (see FIGS. 8 and 9).

At this time, since the two learning data have a learning time longer than the deterioration time of the S / N, at least one of the two learning data has a learning time of S / N.
The system can be correctly estimated because it does not suffer from the deterioration of / N.

According to the transmission method and the transmission system according to the embodiment of the present invention, estimation is performed using error-free learning data in a propagation system in which S / N degradation or instantaneous interruption occurs periodically or intermittently. Since the selected transmission system is selected, there is an effect that data transmission can be stabilized.

[0032]

According to the present invention, on the modulation side, a plurality of different types of learning data are added to transmission data to generate and modulate a frame, and the demodulation side detects a modulated signal.
The detection signal is subjected to an equalization process of estimating a transmission path using a plurality of types of learning data, and an estimated detection signal having few errors in each of the equalization processes is selected. Since the transmission method uses signal demodulation, even if there is an error in certain learning data, it is possible to select and demodulate a detection signal that has been equalized using learning data that does not contain errors. There is an effect that can be reduced.

Further, according to the present invention, the modulating unit includes frame generating means for generating a frame by adding a plurality of types of learning data to transmission data, and modulating means for modulating the generated frame. A demodulation unit is provided according to a plurality of types of learning data, and a detection unit that detects a modulated wave, a synchronization unit that establishes synchronization and outputs a frame synchronization signal, and supports a detection signal according to the frame synchronization signal. Learning means for outputting an equalization parameter for bringing the learning data to be approximated to the original learning data, and phase correction by the equalization parameter input from the corresponding learning means, which is provided corresponding to the learning means. Equalization means for performing equalization processing of, and a selection means for inputting a phase-corrected detection signal output from each equalization means and selecting a signal having a small error,
Since the transmission system includes a demodulation unit that demodulates the signal selected by the selection unit, even if there is an error in certain learning data, a detection signal that has been equalized using learning data that does not include an error is selected. And demodulation can be performed, thereby reducing transmission data errors.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a modulation unit according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing transmission frame generation according to the embodiment of the present invention.

FIG. 3 is a functional block diagram of a demodulation unit according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a reception result output example according to the embodiment of the present invention.

FIG. 5 is a functional block diagram of a conventional modulation unit.

FIG. 6 is an explanatory diagram showing conventional transmission frame generation.

FIG. 7 is a functional block diagram of a conventional demodulation unit.

FIG. 8 is an explanatory diagram showing a case where rotor modulation occurs.

FIG. 9 is an explanatory diagram showing a conventional reception result output example.

[Explanation of symbols]

1, 1 '... frame generation circuit, 2 ... modulation circuit, 3 ...
Detection circuit 4, Synchronization circuit 5, Learning circuit 6, Equalization circuit 7, Selection circuit 8, Demodulation circuit

Claims (2)

[Claims] 1. A modulating side adds a plurality of different types of learning data to transmission data to generate and modulate a frame, and detects a modulated signal on a demodulating side. Performing an equalization process of estimating a transmission path using a plurality of types of learning data, selecting an estimated detection signal having few errors in each equalization process, and demodulating the selected detection signal. Characteristic transmission method. 2. A modulating unit comprising: frame generating means for generating a frame by adding a plurality of types of learning data to transmission data; and modulating means for modulating the generated frame. Detecting means for detecting a modulated wave, synchronizing means for establishing synchronization and outputting a frame synchronization signal, and corresponding learning of the detection signal provided in accordance with the plurality of types of learning data in accordance with the frame synchronization signal. Means for outputting an equalization parameter for bringing the data for use closer to the original learning data, and phase correction by the equalization parameter input from the corresponding learning means provided for the learning means. Equalization means for performing equalization processing, and a detection means that receives the phase-corrected detection signal output from each of the equalization means and selects a detection signal with less error,
And a demodulating means for demodulating the detection signal selected by the selecting means.