JP2000174731A - Electric lamp line communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve transmission efficiency by using a transmission parameter corresponding to quality as the data transmission line of an electric lamp line in electric lamp communication. SOLUTION: In a transmission side, a transmission result based on a response from a reception side is stored in a transmission result storage part 10. The types of the transmission results are normal transmission, a transmission frame error, a response frame error and a non-response. Points are allocated to the transmission results. A transmission line state judgment part 11 reads the past transmission result from the transmission result storage part 10 and executes an operation for grasping the quality of a data transmission line from the points of the transmission results. A transmission control part 9 sets a transmission parameter such as information frame length in accordance with the quality of the data transmission line, which is obtained in the operation. Thus, the generation frequency of retransmission is reduced and transmission efficiency improves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power line communication apparatus for transmitting and receiving digital data using a power line.
In particular, the present invention relates to a power line communication device that sets a transmission parameter such as a frame length so as to obtain an optimum transmission efficiency with a change in a transmission error occurrence rate.

[0002]

2. Description of the Related Art In power line communication, an existing power line is used for data transmission, and it is not necessary to lay a new data transmission line.
Application to N and the like is being studied. However, in the power line,
Since a large number of home electric appliances are connected and noise generated from those appliances appears, the environment of the data transmission path is poor. Further, since a large number of home appliances are connected, the impedance is extremely low in a frequency region used for data transmission, and the data signal is greatly attenuated.

[0003] In order to perform data communication well even in such a bad noise environment, application of a spread spectrum modulation method or the like has been studied. However, occurrence of a data error is unavoidable. It is necessary to ensure the reliability of data. However, when the noise level of the power line is high, the occurrence of data errors is repeated, and data is retransmitted frequently, so that the data transmission efficiency is significantly reduced.

In order to reduce the number of data retransmissions in power line communication, for example, a system disclosed in Japanese Patent Laid-Open No. 4-322519 has been proposed. In this method, attention is paid to the fact that the high-level burst noise generated in the power line is synchronized with the cycle of the commercial AC power supply (50 Hz or 60 Hz), and the transmission start time of the retransmission data is determined based on the cycle of the AC power supply. In this way, burst noise is avoided without changing the data frame length, and the number of retransmissions is reduced.

[0005]

However, in recent years, the number of power supplies for home electric appliances that employ an inverter circuit has increased, and the occurrence of noise in a power line has changed. Noise generated from various devices equipped with an inverter circuit has a temporal characteristic synchronized with a power supply cycle, but is generated not continuously but in a burst manner. Moreover, since the average noise level is high, it is difficult to avoid noise by controlling the transmission start time as described above. Also, it is difficult to cope with a data error caused by attenuation of a data signal on a power line.

In view of the above, the present invention has been made in view of the above-mentioned conventional problems. In a data transmission procedure in which an information frame including data is transmitted from a transmitting side and a response frame is returned from a receiving side, a response from a receiving side is used. Based on the quality of the power line data transmission path, the information frame length transmitted according to this quality and the maximum number of continuous information frames that can be transmitted at one time without waiting for a response from the receiving side It is an object of the present invention to provide a power line communication device capable of changing transmission parameters such as the above and thereby reducing the number of retransmissions of data.

[0007]

To achieve the above object, a power line communication device according to the present invention comprises a communication unit for transmitting and receiving data through a power line, and an error detection unit for detecting an error in received data. A transmission result storing means for storing and storing a transmission result for each communication partner at the time of data transmission, and a transmission path state analyzing means for determining a quality of the power line as a data transmission path using the transmission result. Determining a transmission parameter including at least one of a frame length of transmission data and a maximum number of consecutive frames that can be transmitted at one time based on the quality of the data transmission path determined by the transmission path state analyzing means. Transmission parameter determination means, frame generation means for generating a frame of transmission data with reference to the transmission parameters, and adding an error detection code to the frame And Ri code generating adding means, and a no-response determination means for detecting that there is no response from the receiving side for the data transmission.

According to the present invention, a transmission parameter including at least one of a frame length of transmission data and a maximum number of consecutive frames that can be transmitted at one time is determined based on the quality of a data transmission path. The transmission data frame is generated and transmitted with reference to the transmission parameters.
For example, if the quality of the data transmission path is good, increase the frame length of the transmission data and increase the maximum number of continuous frames,
If the quality of the data transmission path is poor, the frame length of the transmission data is shortened and the maximum number of continuous frames is reduced, thereby improving the data transmission efficiency and reducing the number of retransmissions.

In one embodiment, the apparatus further comprises coding means for performing error correction coding on transmission data, and decoding means for decoding received data subjected to error correction coding, wherein the transmission parameter determined by the parameter determination means is , At least one of the presence or absence of encoding in the encoding means, the type of code, and the encoding rate.

For example, if the quality of the data transmission path is good,
Without encoding, select the type of code with low redundancy, reduce the coding rate, if the quality of the data transmission path is poor, perform encoding, select the type of code with high redundancy, select the code Increase the conversion rate. As a result, it is possible to further improve the data transmission efficiency and further reduce the number of retransmissions.

In one embodiment, for each transmission, the type of transmission result stored in the transmission result storage means includes information indicating that the transmission data has been transmitted to the receiving side without error, and an error in the transmission data. Information indicating the existence or the extent of the error, information indicating the existence of an error in the response data from the receiving side, or the degree of the error, and the response from the receiving side to the data transmission Is information indicating that there was no.

The quality of the data transmission path can be accurately determined based on such a transmission result.

In one embodiment, a predetermined score is assigned to the type of the transmission result stored in the transmission result storage means, and the transmission path state analysis means includes:
An operation is performed using the score corresponding to the past transmission result stored in the transmission result storage means, and the quality of the data transmission path is determined based on the result of the operation.

By allocating each score to the type of transmission result in this way, it is possible to simplify the determination of the quality of the data transmission path.

In one embodiment, the calculation by the transmission path state analyzing means is a calculation for obtaining an average number of points per unit transmission from respective points corresponding to a plurality of past transmission results.

By referring to the history of the transmission results in the past, the quality of the data transmission path can be determined more reliably.

In one embodiment, the calculation by the transmission path state analysis means is a weighted average calculation weighted by the elapsed time since the transmission was performed. Weight is large.

As described above, the quality of the data transmission path can be determined more accurately by increasing the weight as the score corresponding to the temporally new transmission result.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing Embodiment 1 of a power line communication device according to the present invention. This power line communication device is also used as a transmission device and a reception device, and when operating as a transmission device, transmits an information frame,
When receiving a response frame from the receiving device and operating as a receiving device, the information frame from the transmitting device is received and the response frame is transmitted.

The general operation of the power line communication device of the present embodiment as a transmission device is as follows.

The frame forming unit 1 receives transmission data and forms an information frame including the transmission data. In addition, the frame configuration unit 1 has, for example,
A transmission parameter indicating the maximum number of continuous information frames that can be transmitted at one time without waiting for a response from the receiving side is input from the transmission control unit 9 and at least one information frame (one (Information frames or continuous information frames equal to or less than the maximum number of continuous information frames). The information frame configured by the frame configuration unit 1 is output to the error detection code addition unit 2.

The error detecting code adding section 2 calculates and finds an error detecting code for each information frame from the frame forming section 1 and incorporates this error detecting code into the information frame.
This information frame is output to modulation section 3.

The modulation section 3 modulates the information frame from the error detection code adding section 2 and outputs a modulated signal to the power line coupling section 4. The power line coupling unit 4 is connected to a power line (not shown), and superposes a modulated signal from the modulation unit 3 on the power line. Further, the modulation unit 3 outputs a timing signal to the no-response determination unit 5 when the modulation of one information frame is completed.

The power line coupling unit 4 extracts the modulated signal superimposed on the power line and outputs it to the demodulation unit 6. The demodulation unit 6 demodulates the modulated signal and reproduces a response frame from the receiving side. The error detection unit 7 receives the demodulated response frame, performs an operation for detecting an error in data included in the response frame, and outputs data indicating the presence or absence of a data error in the response frame to the reception content analysis unit 8. , And outputs the data of the response frame to the reception content analysis unit 8.

Upon receiving the timing signal from the modulation circuit 3, the no-response determining unit 5 determines whether there is a response frame from the receiving side to the transmission of the information frame for a certain period of time after the timing signal is input. 6 is determined based on the demodulated output. When it is determined that there is no response frame from the receiving side, the no-response determining unit 5 outputs data indicating that there is no response from the receiving side to the transmission control unit 9 and the transmission result storage unit 10.

If the error detection unit 7 does not detect an error in the data included in the response frame, the received content analysis unit 8 analyzes the content of the response frame and determines that the content of the response frame is an acknowledgment (hereinafter referred to as ACK). ) And a negative acknowledgment (hereinafter referred to as NAK) are output to the transmission control unit 9 and the transmission result storage unit 10.

The transmission result storage unit 10 stores data from the error detection unit 7 (indicating the presence or absence of an error in the data included in the response frame) and data from the reception content analysis unit 8 (response to a certain period or a certain number of transmissions). (Shows the contents of the frame) and data (shows no response) from the no-response determination unit 5. The transmission path state determination unit 11 uses the data in the transmission result storage unit 10 (indicating the presence or absence of an error in the data included in the response frame, the content of the response frame for a certain period or a certain number of transmissions, and no response). Then, the quality of the power line as a data transmission path is determined and output to the transmission control unit 9.

The transmission control unit 9 determines the information frame length and the maximum number of continuous information frames that can be transmitted continuously at one time without waiting for a response from the receiving side, based on the quality of the power line as a data transmission path. The transmission parameter to be indicated is determined, and the transmission parameter is output to the frame configuration unit 1. In addition, the transmission control unit 9 detects an error in the data included in the response frame by the error detection unit 7, determines that there is no response by the no-response determination unit 5, and determines whether the NAK of the response frame is When the data is extracted, retransmission of the transmission data is determined, and data indicating the result is output to the frame configuration unit 1. In response to this, the frame composing unit 1 determines retransmission of the transmission data, and composes an information frame including the transmission data that has been transmitted at least once based on the transmission parameter from the transmission control unit 9. The information frame is output to the modulator 3 and the transmission data is retransmitted.

The schematic operation of the power line communication device of the present embodiment as a receiving device is as follows.

The power line coupling unit 4 extracts the modulated signal superimposed on the power line and outputs the signal to the demodulation unit 6. The demodulation unit 6 demodulates the modulated signal, reproduces and outputs an information frame from the transmission side. The error detection unit 7 receives the demodulated information frame, performs an operation for detecting an error in data included in the information frame, and outputs data indicating the presence or absence of a data error in the information frame to the reception content analysis unit 8. The data is output to the transmission control unit 9 and the transmission result storage unit 10, and the data of the information frame is output to the reception content analysis unit 8.

If the error detector 7 does not detect an error in the data contained in the information frame, the received content analyzer 8 outputs the data of the information frame.

If the error detection unit 7 does not detect an error in the data included in the information frame, the transmission control unit 9 forms a response frame indicating ACK, and if the error in the data included in the information frame is detected. For example, a response frame indicating NAK is formed, and this response frame is output to the modulation unit 3.

The modulating section 3 modulates the response frame from the error detecting code adding section 2 and outputs a modulated signal to the power line coupling section 4.

FIG. 2 shows a connection state of two power line communication devices having the configuration shown in FIG. In FIG.
One power line communication device 100 operates as a transmitting side, and the other power line communication device 200 operates as a receiving side. In the power line communication device 100 on the transmission side, blocks necessary for transmitting an information frame and receiving a response frame from the reception device are described, and have the same configuration as the device of FIG. I have. Also, the power line communication device 1 on the receiving side
At 00, only the blocks necessary to receive the information frame from the transmitting device and transmit the response frame, that is, except for the no-response determining unit 5, the transmission result storage unit 10, and the transmission path state determining unit 11, Each block is described.

FIG. 3 shows a power line communication device 1 on the transmitting side.
FIG. 4 is a flowchart showing the operation of the power line communication device 200 on the receiving side. The operation of the power line communication device 100 on the transmission side and the operation of the power line communication device 200 on the reception side will be described in more detail with reference to these flowcharts.

First, the operation of the power line communication device 100 on the transmitting side will be described with reference to the flowchart shown in FIG. In the power line communication device 100 on the transmitting side, the frame composing unit 1 determines the presence or absence of transmission data (S1), and waits until transmission data is present (S1, Yes). When there is transmission data (S1, Yes), the frame forming unit 1
Determines whether the transmission of the transmission data is the first transmission or retransmission due to the occurrence of a transmission error based on the data from the transmission control unit 9 (S2). As described above, the transmission control unit 9 controls the error detection unit 7 to detect an error in the data included in the response frame, the non-response determination unit 5 to determine no response, the reception content analysis unit 8
Then, when the NAK of the response frame is extracted, retransmission of transmission data is determined. In response to this, the frame configuration unit 1 determines retransmission of the transmission data.

In the case of the initial transmission, the transmission control unit 9 determines, for example, the information frame length and the information frame length at once without waiting for a response from the receiving side based on the quality of the power line as the data transmission line from the transmission line state determining unit 11. A transmission parameter indicating the maximum number of continuous information frames that can be continuously transmitted is determined (S3). When determining the transmission parameters, if it is determined that the quality of the power line as a data transmission path is poor, the probability that the data transmission period on the power line and the noise generation period overlap is reduced to reduce the occurrence of information frame retransmission. In order to reduce the frequency, for example, a short information frame length is selected, and the maximum number of continuous information frames is set small.

In the case of retransmission of the information frame, the transmission control unit 9 refers to the transmission parameter used in the previous transmission of the information frame, and sets the information frame length shorter than the set value.
A small maximum number of continuous information frames is reset (S4).

The frame forming unit 1 incorporates transmission data into an information frame within a range not exceeding the information frame length determined by the transmission control unit 9. In addition, the frame forming unit 1 converts the information frame into a plurality of information frames as necessary based on the relationship between the transmission data length and the information frame length within a range not exceeding the maximum number of continuous information frames determined by the transmission control unit 9. It is divided (S5).

If the entire transmission data cannot be incorporated into each information frame that can be transmitted continuously at one time, the transmission data is divided into a plurality of parts, and the data part is once divided for each divided data part. In each information frame which can be continuously transmitted.

The error detecting code adding section 2 calculates and finds an error detecting code for each information frame from the frame composing section 1 and adds this error code to the information frame (S
6). As a code for error detection, for example, a CRC code is used.

The modulator 3 modulates the information frame to which the error detection code has been added (S7), and sends the modulated signal to the power line 300 via the power line coupler 4. As a modulation method used here, a method that is not easily affected by noise, distortion, or the like, which is a problem in power line communication, is preferable. For example, a spread spectrum modulation method is preferable.

The non-response determining unit 5 counts a predetermined time from a time point when a timing signal indicating the end of the output of the modulation signal from the modulation unit 3 is input by a timer circuit built in the non-response determining unit 5. Is determined based on the demodulation output of the demodulation unit 6 (S8). If there is no response frame (S8, Yes), the non-response determination unit 5
Records data indicating no response in the transmission result storage unit 10 (S10). Thereafter, the process proceeds to S14.

If there is a response frame (S8, No), the response frame is demodulated by the demodulation unit 6 (S8).
9).

The error detector 7 detects an error in the data contained in the demodulated response frame (S11). If a data error is detected (S11, Yes), the error detector 7 generates data indicating the transmission error of the response frame. It is recorded in the transmission result storage unit 10 (S13). Thereafter, the process proceeds to S14.

If no data error has been detected (S11, No), the received content analysis unit 8 analyzes the data of the response frame and determines whether the response from the receiving side is ACK or NA.
It is determined which of K is indicated (S12).

If the response from the receiving side is determined to be ACK (S12, Yes), it is possible to determine that the information frame transmitted from the transmitting side device 100 has reached the receiving side without error, so that the received content analysis unit 8 Records data indicating normal transmission of the information frame in the transmission result storage unit 10 (S1).
5). Thereafter, the process proceeds to S14.

If the response from the receiving side is determined to be NAK (S12, No), it can be determined that the information frame transmitted from the transmitting side device 100 has arrived at the receiving side by mistake, so that the information frame transmission error Is recorded in the transmission result storage unit 10 (S16). Thereafter, the process proceeds to S14.

As is apparent from the above description, in one transmission of the information frame, any one of the transmission results of no response, transmission error of the response frame, normal transmission of the information frame, and transmission error of the information frame is obtained. Transmission result storage unit 1
0 is stored. Each transmission result within a certain number of times or within a certain time before the transmission of this information frame is also stored in the transmission result storage unit 10 in a time series in the same procedure.

The transmission path state determination unit 11 performs an operation for estimating the quality of the data transmission path by using the current transmission result stored in the transmission result storage unit 10 and the past transmission result, The quality of the data transmission path obtained by this calculation is stored as the latest one (S14). Thereafter, the process returns to S1. The calculation for estimating the quality of the transmission path will be described later.

According to the above procedure, the quality of the latest transmission path can be ascertained in one transmission of an information frame. In the next and subsequent transmissions, the transmission control unit 9 transmits It is possible to select the optimum frame length and the maximum number of continuous information frames based on the latest quality of the transmission path.

Next, the operation of the power line communication device 200 on the receiving side will be described with reference to the flowchart shown in FIG. In the power line communication device 200 on the receiving side, the power line coupling unit 4
Determines whether there is a modulated signal on the power line 300 (S20), and waits until the signal is present (S20, Yes). If there is a modulated signal (S20, Yes), the demodulation unit 6 demodulates the modulated signal, reproduces an information frame from the transmission side (S21), and outputs this information frame to the error detection unit 7. I do.

The error detector 7 detects an error in the data contained in the information frame (S22). If a data error is detected (S22, Yes), the received content analysis unit 8
Discards the data of the information frame (S23b). At this time, the transmission control unit 9 receives data indicating a transmission error of the information frame from the error detection unit 7 and generates data indicating a NAK to be returned to the transmission side (S25).

If no data error is detected (S22, No), the received content analysis unit 8 outputs the data of the received information frame (S23a). Further, the transmission control unit 9 receives data indicating normal transmission of the information frame from the error detection unit 7 and generates data indicating ACK returned to the transmission side (S24).

The AC previously generated by the transmission control unit 9
The data indicating either K or NAK is output to the frame forming unit 1 and is incorporated into the response frame (S26), and the error detection code adding unit 2 adds an error detection code to the response frame (S26). S27). The response frame to which the error detection code is added is modulated by the modulation unit 3 and then transmitted to the power line 300 via the power line coupling unit 4 (S28).

Thus, the reception of the information frame and the response thereto have been completed, and the process returns to S20 to wait for the next reception.

Next, the calculation performed in the transmission path state determination unit 11 will be described. In the transmission result storage unit 10,
Each time at least one continuous information frame is transmitted once, a transmission result of one of a no-response, a transmission error of a response frame, a normal transmission of an information frame, and a transmission error of an information frame is stored. Alternatively, each transmission result within a fixed time is stored.

When these four types of transmission results are compared,
First, in the case of normal transmission of an information frame, both the information frame from the transmission side and the response frame from the reception side were transmitted without error, and the quality of the power line data transmission path is estimated to be the best. .

In the case of no response, it is considered that at least one of the information frame signal and the response frame signal has deteriorated in the data transmission path to such an extent that demodulation cannot be performed. Presumed to be bad.

Next, the transmission error of the information frame and the transmission error of the response frame are compared. An information frame transmission error occurs when an error is detected in the information frame on the receiving side and no error is detected in the response frame on the transmitting side. On the other hand, the transmission error of the response frame occurs when an error is detected in the response frame on the transmission side regardless of the error detection result of the information frame on the reception side. If there is an error in both, the transmission result may be a transmission error of the response frame. Therefore, it is estimated that the probability that the quality of the transmission path is in a good state is higher in the case of an information frame transmission error.

Since the quality of each transmission path estimated based on each transmission result is ranked as described above, each transmission path quality point is assigned to each transmission result.
For example, 4 points for normal transmission of an information frame,
At least three points are allocated for information frame transmission errors, two points for response frame transmission errors, and one point for no response.
Each time one information frame is transmitted, the point of the transmission result is stored in the transmission result storage unit 10. Then, the transmission control unit 9 calculates an average point per information frame transmission from points of each transmission result within a predetermined number of times or within a predetermined time in the past, and calculates the average point and the average point associated with a new transmission. , The quality of the current transmission path is determined. In the case of assigning each point to each transmission result described above, it can be seen that the larger the average point, the better the transmission path quality.

When the degree of transmission error, that is, the degree of data error in a frame, is obtained as a transmission result, points may be set more finely in accordance with the degree of transmission error.

Since the transmission result storage unit 10 stores each transmission result in time series, a large weight is applied to a point of a transmission result that is newer in time when calculating the average point. It is also possible to obtain a weighted average. For example, an operation such as multiplying the point for the latest transmission result by 1, multiplying the point for the previous transmission result by 0.9, and multiplying the point for the second previous transmission result by 0.8. After that, if the points of each transmission result for a certain number of times are totaled and a weighted average is calculated, it is possible to grasp the quality of the data transmission path more accurately. Particularly, in power line communication where the quality of the data transmission line changes rapidly, optimal transmission parameters according to the quality of the data transmission line, that is, the information frame length and the maximum number of continuous information frames, etc., are required to maintain the transmission efficiency. Since it is necessary to make settings and it is important to know the correct quality of the data transmission path at the present time, the above estimation of the quality of the data transmission path is effective.

As described above, according to the present embodiment, it is possible to accurately estimate the quality of the data transmission path from the past transmission results stored in the transmission result storage unit 10, and to obtain the optimum transmission parameters. That is, the frame length and the maximum number of continuous information frames can be determined. Thereby, even when the quality of the data transmission path is deteriorated, it is possible to reduce the frequency of occurrence of retransmission, suppress a decrease in the efficiency of data transmission, and when the quality of the data transmission path is good, By changing the transmission parameters, the transmission efficiency can be quickly improved.

In this embodiment, the quality of the data transmission path is obtained by averaging the points of each transmission result. However, an approximation function that approximates the temporal change of the points is obtained, and the integration operation of the function is performed. Alternatively, the quality of the data transmission path may be obtained by performing a differential operation or the like, and the effect of the present invention can be obtained by any other method that can reflect the quality of the data transmission path.

In the present embodiment, two power line communication devices are connected to a power line, and one device is a transmitting device and the other device is a receiving device. Since the receiving side device usually has the same function and configuration, the same operation is performed even if the transmitting side and the receiving side are switched, and the effect is not changed. Also, when three or more power line communication devices are connected to the power line, each power line communication device uses a past transmission result (transmission result) for every other power line communication device that is a communication partner. History) is stored in the transmission result storage unit 10, and the same effect is achieved by the transmission control unit 9 using the transmission result history of each communication partner.

(Embodiment 2) FIG. 5 is a block diagram showing Embodiment 2 of the power line communication device of the present invention. The power line communication device of the present embodiment is obtained by additionally inserting an error correction encoding unit 13 and an error correction decoding unit 12 into the device shown in FIG. In FIG. 5, the same reference numerals are given to portions that perform the same operations as in FIG. 1, and description thereof will be omitted.

In the power line communication device on the transmission side, the transmission control unit 9 determines whether or not to perform error coding based on the quality of the data transmission path from the transmission path state determination unit 11 as a transmission parameter. Correction encoding section 13
Give to.

When the error encoding is instructed by the transmission parameter, the error encoding unit 13 performs an error correction code process on the information frame from the detection code adding unit 2 and further determines that the error encoding is performed. The indicated data is included in the information frame, and the obtained information frame is output. Further, when it is instructed not to perform the error coding by the transmission parameter, the correction coding unit 13 does not perform the error correction coding process on the information frame from the detection code adding unit 2 and further does not perform the error coding. Is included in the information frame, and the information frame is output. The information frame output from the correction encoding unit 13 is
And then output to the power line coupling unit 4.

In the power line communication device on the receiving side, when the information frame is input from the power line coupling unit 4 via the demodulation unit 6, the error correction decoding unit 12 performs error correction code processing based on the data in the information frame. Is determined. When the error correction decoding unit 12 determines that the error correction code processing has been performed, the error correction decoding unit 12 performs error correction decoding processing on the information frame, and outputs the obtained information frame to the error detection unit 7. Output. When the error correction decoding unit 12 determines that the error correction code processing has not been performed, the error correction decoding unit 12 outputs the information frame to the error detection unit 7 without performing the error correction decoding processing on the information frame. .

In the power line communication device on the transmitting side,
The quality of the data transmission path is determined by the same processing as in the first embodiment. The transmission control unit 9 can determine not only the presence or absence of correction coding according to the quality of the data transmission path, but also the coding rate of error correction processing, the type of code, and the like as transmission parameters. The correction encoding unit 13
Based on the determined presence / absence of coding, the determined coding rate and code type, the information frame is not coded or not coded. An error correction code process is performed, and data indicating presence / absence of error coding, a coding rate, and a code type is included in an information frame, and the information frame is output to the modulation unit 3. In the power line communication device on the receiving side, when the received information frame is input, the error correction decoding unit 12 determines presence / absence of error correction coding, a coding rate, and a code type based on data in the information frame. When the error correction code processing is performed, the information frame is subjected to error correction decoding processing corresponding to the coding rate and the type of error correction coding, and the information frame obtained by this is output.

Thus, for example, when the quality of the data transmission path is good, it is possible to select not to perform coding, to reduce the coding rate, or to use a coding method with less redundant bits. If the quality of the data transmission path is poor, improve the transmission efficiency by selecting coding, increasing the coding rate, or using a coding method with many redundant bits. It becomes possible.

Regarding the type of error correction code, the same effect can be obtained with any code such as a BCH code or Reed-Solomon code that can automatically correct error bits in the decoding process on the receiving side.

[0075]

As described above, according to the present invention, the transmission side stores the transmission result based on the response from the reception side for each data transmission, and uses the result to transmit the data. Know the quality of the road accurately. This makes it possible to select a transmission parameter such as an information frame length suitable for the quality of the data transmission path, thereby reducing the frequency of retransmissions and improving transmission efficiency.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a power line communication device according to a first embodiment of the present invention.

FIG. 2 is a power line communication device on the transmitting side, which extracts components necessary for the transmitting side in the apparatus of FIG. 1, and the receiving side which extracts components necessary for the receiving side in the apparatus of FIG. It is a block diagram showing a power line communication device.

FIG. 3 is a flowchart illustrating an operation of the power line communication device on the transmission side in FIG. 2;

FIG. 4 is a flowchart showing an operation of the power line communication device on the receiving side in FIG. 2;

FIG. 5 is a block diagram illustrating a power line communication device according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame structure part 2 Error detection code addition part 3 Modulation part 4 Light line coupling part 5 No response determination part 6 Demodulation part 7 Error detection part 8 Reception content analysis part 9 Transmission control part 10 Transmission result storage part 11 Transmission path state determination part REFERENCE SIGNS LIST 12 error correction decoding unit 13 error correction encoding unit 100 transmitting apparatus 200 receiving apparatus 300 power line

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Iwamoto, Inventor 1006 Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 5K014 AA01 DA01 DA03 EA00 FA03 FA11 FA13 HA00 5K046 AA03 BB05 PS39 PS44 PS49

Claims (6)

[Claims] 1. A communication means for transmitting and receiving data through a power line, an error detection means for detecting an error in received data, and a transmission result for storing and storing a transmission result for each communication partner when transmitting data. A storage unit, a transmission line state analysis unit that determines the quality of the power line as a data transmission line using the transmission result, and a transmission based on the quality of the data transmission line determined by the transmission line state analysis unit. Transmission parameter determining means for determining a transmission parameter including at least one of a data frame length and a maximum number of continuous frames that can be transmitted continuously at one time; and generating a frame of transmission data with reference to the transmission parameter. Frame generating means; error detecting code generating and adding means for adding an error detecting code to the frame; and a response from the receiving side to data transmission. Power line communication device being characterized in that a no-response determination means for detecting the absence. 2. An apparatus according to claim 1, further comprising: an encoding unit that performs error correction encoding on the transmission data; and a decoding unit that decodes the error correction encoded reception data. 2. The power line communication device according to claim 1, wherein the power line communication device includes at least one of the presence or absence of encoding in the encoding unit, the type of code, and the encoding rate. 3. For each transmission, the type of transmission result stored in the transmission result storage means includes information indicating that transmission data has been transmitted to the receiving side without error, and information indicating that an error exists in the transmission data. Or information indicating the extent of the error, and information indicating the presence of an error in the response data from the receiving side, or information indicating the extent of the error, and no response from the receiving side to the data transmission. 3. The power line communication device according to claim 1, wherein the power line communication device is information indicating the power line communication device. 4. A predetermined score is assigned to each type of transmission result stored in said transmission result storage means, and said transmission path state analysis means is stored in said transmission result storage means. The power line communication device according to claim 3, wherein an operation is performed using the score corresponding to a past transmission result, and the quality of the data transmission path is determined based on the result of the operation. 5. The calculation by the transmission path state analysis means is as follows:
5. The power line communication device according to claim 4, wherein the calculation is for calculating an average number of points per unit transmission from respective points corresponding to a plurality of past transmission results. 6. The calculation by the transmission path state analysis means includes:
5. The power line communication apparatus according to claim 4, wherein the weighted average calculation is weighted based on an elapsed time since the transmission is performed, and the score corresponding to the temporally new transmission result has a larger weight. .